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{GI Slips for Librarians to paste on Catalogue Cards. 

N.B.—Take out carefully, leaving about quarter of an inch at 
the back, To do otherwise would, in some cases, release other 
leaves. 


MARTIN, H. NEWELL.—The Human Body. 
An Account of its Structure and Activities, and 
the conditions of its healthy working, by H. New- 
ell Martin, D. Sc., M. A., M.B., Professor of Biol- 
ogy in the Johns Hopkins University ; Fellow of 
University College, London; late Fellow of Christ's 
College, Cambridge. New York: Henry Holt & 
Co., 1881. Large 12mo, pp. xvi. 606, Appendix 
33. (American Science Series.) 


HUMAN BODY, THE.—An Account of its 
Structure and Activities, and the conditions of its 
healthy working, by H. Newell Martin, D, Sc., M- 
A., M. B., Professor of ee ke in the Johns Hop- 


kins University; Fellow o: istventy College, 
London; late Fellow of Christ's College, Cam- 
bridge. New York: Henry Holt & Co,, 1881, 
Large r2mo, pp, xvi, 606, Appendix 33. (Ameri- 
can Science Series.) 


ANATOMY.—The Human Body, An Account 
of its Structure and Activities, and the conditions 
of its healthy working, by H, Newell Martin, D, 
Sc., M. A., x B., Professor of Biology in the 
Johns Hopkins University; 3 Fellow of University 
College, London; late Fellow of Christ's College, 
Cambridge. New York: Henry Holt & Co., 1881, 
Large 12mo, pp. xvi. 606, Appendix 33. (Ameri- 
can Science Series.) 


PHYSIOLOGY.—The Human Body, An Ac- 
count of its Structure and Activities, and the con- 
ditions of its healthy working, by H, Newell Mar- 
tin, D. Sc., M. A., M. B., Professor of Biology in 
the Johns Hopkins University; ; Fellow of Univer- 
sity College, London ; late Fellow of Christ's Col- 
lege, Cambridge, New York: Henry Holt & 
Co., 1881. Large r2mo, pp. xvi. 606, Appendix 
33- (American Science Series.) 








AMERICAN SCIENCE SERTES 


FOR HIGH SCHOOLS AND COLLEGES. 


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By Anticon W. Waser, Pro- Ry A. 8. Packann, Jn, Pro- 
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zecey eS ee of the 
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By Samurt W. Jomxsox nud) 5, 
Wituns G Mixren, Profesiors | "+ The Human Body.* 


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HENRY HOLT & CO,, Ponimamns, NEW YORK. 





AMERICAN SCIENCE SERIES 


THE HUMAN BODY 





AN ACCOUNT OF ITS STRUCTURE AND ACTIVITIES 
AND THE CONDITIONS OF ITS HEALTRY WORKING 


i 


Wf. NEWELL MARTIN, D.Sc., M.A., MB. 
= 


Profesor of Biology in the Johns Hopkins University 
Fellow of University College, London » Late 
Fillow of Christ's Coltege, 


NEW YORK 
HENRY HOLT AND COMPANY 
881 











Copyright, 2, 


wr 
Hexny Hour & Co, 


~VGaonuna, 
PRONE, 
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PREFACE. 


Tx the following pages I have endeavored to give an 
account of the structure and activities of the Human Body, 
which, while intelligible to the general reader, shall be 
accurate, and sufficiently minute in details to meet the 
requirements of students who are not making Human 
Anatomy and Physiology subjects of special advanced study. 
Wherever it seemed to me really profitable, hygienic topica 
have also been discussed, though at first glance they may 
seem less fully treated of than in many School or College 
‘Text-books of Physiology. Whoever will take the trouble, 
however, to examine critically what passes for Hygiene in 
the majority of such cases, will I think find that, when 
correct, much of it is platitude or truism: since there is so 
much that is of importance and interest to be snid it seems 
hardly worth while to occupy space with insisting on the 
commonplace or obvious. 

It is hard to write a book, not designed for specialists, 
without running the risk of being accused of dogmatism, 
and some readers will, no doubt, be inclined to think that, in 
several instances, I hare treated as established facts matters 
which are still open to discussion. General readers and 
students are, however, only bewildered by the production of 
an array of observations and arguments on each side of every 
question, and, in the majority of casos, the chief responsi- 
bility under which the author of a text-book lies is to 
what seem to him the best supported views, and th 


discoveries of the future. 
Others will, I am inclined to think, raise the contrary 





Copyright, rat, 
ay 


Hexay Hour & © 


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TAISERR. 
13 Vandowater St, 3% 








iv PREFACE, 


objection, that too many disputed matters have been dis- 
cussed; this was deliberately done asthe result of an experi- 
ence in teaching Physiology which now extends over more 
than ten years. It would have been comparatively easy to 
slip over things still uncertain and subjects as yet unin- 
yestigated, and to represent our knowledge of the workings 
of the animal body as neatly rounded off at all its contours 
and complete in all its details—fofus, teres, et rotundus. 
But by so doing no adequate idea of the present state of 
physiological science would have been conveyed; in many 
direetions it is much farther travelled and more completely 
known than in others; and, as ever, exactly the most in- 
teresting points are those which lie on the boundary 
between what we know and what we hope to know. In 
gross Anatomy there are now but few points calling 
for a suspension of judgment; with respect to Micro- 
scopic Anatomy there are more; buta treatise on Physiology 
which would pass by, unmentioned, all things not known 
but sought, would convey an utterly unfaithful and untrue 
idea. Physiology has not finished its course; it is not cut 
and dried, and ready to be laid aside for reference like a 
specimen in an Herbarium, but is comparable rather to a 
living, growing plant, with some stout and useful branches 
well raised into the light, others but part grown, and 
many still represented by unfolded buds, ‘To the teacher, 
moreover, no pupil is more discouraging than the one who 
thinks there is nothing to learn; and the boy who has 
“finished” Latin and ‘‘ done” Geometry finds sometimes his 
counterpart in the lad who has“ gone through” Physiology. 
For this unfortunate state of mind many Text-books are, T 
believe, much to blame: difficulties are too often ignored, or 
opening vistas of knowledge resolutely kept ont of view: the 
forbidden regions may be, it is true, too rough for the young 
student to be gnided throngh, or as yet pathless for the 
pioneers of thought; but the opportunity to arouse the re- 
coptive mental attitude apt to be produced by the recogni- 
tion of the tact that much more still remain be learnt— 
to excite the exercise of the reasoning faculties upon dis- 
puted matters—and, in some of the better minds, to arouse 





PREFACE. v 


the longing to assist in adding to knowledge, is an inesti- 
mable advantage, not to be lightly thrown aside through 
the desire to make an elegantly symmetrical book. While 
I trust, therefore, that this volume contains all the more 
important facts at present known about the working of our 
Bodies, I as earnestly hope that it makes plain that very 
much is yet to be discovered. 

A work of the scope of the present volume is, of course, 
not the proper medium for the publication of novel facts; 
bat, while the ‘Human Body,” accordingly, professes to 
be merely a compilation, the introduction of constant ref- 
erences to authorities would have been out of place, I 
trust, however, that it will be found throughout imbued 
with the influence of my beloved master, Michael Foster; 
and on various hygienic topics I have to acknowledge a 
special indebtedness to the excellent series entitled Health 
Primers. 

The majority of the anatomical illustrations are from 
Henlo’s Anatomie des Menschen, and a few from Arendt’s 
Schulatias, the publishers of each furnishing electrotypes. 
A considerable number, mainly histological, are from 
Quain's Anatomy, and a fow figures are after Bernstein, 
Carpenter, Frey, Haeckel, Helmholtz, Huxloy, McKen- 
drick, and Wundt. About thirty, chiefly diagrammatic, 
‘were drawn specially for the work. 

Quantities are throughout expressed first on the metric 
system, their approximate equivalents in American weights 
and measures being added in brackets, 


H. Newent Marry. 


Barrimonsz, October, 1880. 








CONTENTS 


CHAPTER I. 


‘TUX GENERAL STRUCTURE AND COMPOSITION OF THE HUMAN 
noDY. 


Definitions Tismes and organs. Histology, Zoological posi 
tion of man, ‘The vertebrate plan of structure. The mam- 
malia, Chemical composition of the Body 

CHAPTER I. 


THE FUNDAMENTAL PITYAIOLOGICAL ACTIONS. 


‘The propertics of the living Body, Physiological properties. 
Celis, Cell growth, Cell division. Assimilation and repro- 
duction. Contractility. Irritability. Conductivity. Spon- 
tanelty. Protoplasm. ‘The fundamental I puysologica proper- 


CHAPTER IIL. 


THE DIFFERENTIATION OF THK TISSUES, AND THE Pirrsr 
OLOGICAL DIVISION OF EMPLOYMENTS, 


Development. ‘The physiological division of labor. Classifica 
thon of the tissues. Undifferentiated tissues Supporting 
tissues. Nutritive tissnes. Storage tissues, Irritable tissues, 
Co-ordinating and automatic tissues. Motor tissues, Condue- 
Hive tissies. Protective tiseurs Reproductive tissues, Or- 
gant Physiological mechanisms. Apntomical aystems The 
Body as a working whole. . set ? 


Paar 





CONTENTS. 


CHAPTER Iv, 


THE INTERNAL MEDIOM, 


‘The external medium. ‘The intornal medium, The blood. The 
Histology of blood. Blood crystals. Histology of 


38 


CHAPTER VY. 


THE CLOTTING OF THE BLOOD. 


‘The coagulation of blood. Causes of coagulation. Whipped 
blood. The buffy coat, Uses of coagulation. The fibrin 
factors Artificial clot. The fibrin ferment. Exciting causes 
of coagulation. Relation of blood-vessels to coagulation, 
Composition of the blood. Quantity of blood. Origin and fute 
of the blood corpuscles. Chemistry of lymph 


CHAPTER VI. 


THE 8KELETON 


Exoskeleton and endoskeletou. The bony skeleton. Segmenta 
Mon of the skeleton, Peculiarities of the human bony skele- 
POR ser se aver seklen ene eee 


CHAPTER VII. 


VHE STRUCTURE AND COMPOSITION OF BONE. JOINTS 


Gross structure of the bones, Microscopie structure of hone. 
Chemical composition of bone. Hygiene of the bony skeleton. 
Articulations, Joints. Hygiene of the joints... . 


CHAPTER VILL. 


CARTILAGE AND CONNECTIVE TISSUE. 


‘Temporary and permanent cartiluges, Varieties of cartilage 
‘The connective tissues, Elastic cartilage and fibro-cartilage, 





CONTENTS, 


Homologies of the supporting tissues Hygiene of the develop- 
ing skeleton, Adipose tissue. ...... eateries price 


CHAPTER IX. 
THE STRUCTORE OF THE MOTOR OnGANK 


Motion in animals and plants, Amobold cells. Ciliated cells. 
The muscles, Histology of striped muscle. Unstriped mus. 
cles Cardiac muscular tissue, ‘The chemistry of muscular 
tisme. Beef-tea and Liebig’s extract....0....0.4 


CHAPTER X. 


TRE PROPERTIES OF MUSCULAR TIBUE, 


Contractility. Irritability of muscle. A simple muscular cou 
traction, Tetanus, Causes influencing the degree of muscu- 
lar contraction, The measurement of muscular work, Mus- 
cular elasticity. Physiology of plain muscular tissue, Hy- 
gicne of the muscles, Exercise. 


CHAPTER XI. 


MOTION AND LOCOMOTION. 


‘Phe special physiology of muscles, Levers in the Body, ‘The 
erect posture, Walking. Running, Leaping............... 


CHAPTER Xt. 


THR ANATOMY OF THE NEKYOUS sysTEM. 


Nerve-tranks Plexuses. Nerve-centres. The cerebro-spinal 
centre and its membranes, The spinal cord, The spinal 
serves, The brain, The cranial nerves. Ganglia and com 
munications of the cranial nerves. Th mpathetic system. 
The sporadic ganglia, ‘The histology of nerre-fibres. The 
histology of nerve-cella. The structure of the spinal cord, 


ix 


mor 


100 


. 8 


. 4 





CONTENTS, 


CHAPTER XIE 


‘THR GENERAL PiYsrOLooY oF THE NERVOUS SYSTEM 


‘The properties of nerve tissues. The functions of nerve-centres 
and nervetrunks. Excitant and inhibitory nerves. The clas 
sificaton of nerve fibres. Intercentral nerve-fibres The 
stimuli of nerves, General and special nerve stimuli, Specifle 
merve energics. All nerve-fibres are fundamentally alike, 
The nature of a nervous impulse. The rate of transmission of 
anerrous impulse. Functions of the spinal nerve-roots, The 
intercommunication of nerve-centres. 


CHAPTER XLV. 
THE ANATOMY OF THE HEART AND BLOOD YRSSELS. 


General statement. Position of the heart, The membranes of 
the heart, The cavities of the heart, The heart as viewed 
from the outside. The interior of the heart. The valves of 
the heart. The arterial system. The capillaries. ‘The veins. 
‘The pulmonary circulat Tho course of the blood. ‘The 
portal circulation. Arterial and venous blood. The structure 


of arteries, capillaries, and veins, .. <.-....0sc¢c0eeeereaees . 201 


CHAPTER XY. 


THE WORKING OF THE IEART AND BLOOD-VESELS 


‘The beat of the heart. Thecardiacimpulse. Events inn carding 
period, Use of the papillary muscles, Sounds of the heart. 
Function of the auricles. The work done by the heart, The 
blood flow outside the heart. The circulation as seen with 
the microscope. Internal friction in the vessels. The conver- 
sion of an intermittent into a continuous flow... ..... 0.6. 0.6 


CHAPTER XVI 


ARTERIAL PRESSURE AND TUR PULSE. 


Weber's schema. Arterial pressure. Modifications of arterin! 
pressure, and how they may be produced, ‘The pulse. The 


210 





CONTENTS, 


rate of the blood-flow. Secondary causes of the circulation. 
Proofs of the circulation of the blood. 


CHAPTER XVII. 


THE REGULATION OF TITE HHART AXD BLOOD VESSELA BY 
THE NERVOUS SYSTEM. 


‘The need of co-ordination ia the vascular system, Tire \otrinsic 
nerves of the heart. Nerves showing the heart's beat, The 
cardio-inhibitory mechanism, The accelerator nerves of the 
heart, The nerves of the blood-vessels. The vaso-motor 
centre. Tuking cold. Vasodilator nerves. ... 


CHAPTER XVIUL 


THE SECRETORY TESUES AND O1GANS, 


Definition. Organs of secretion, Glands. Physical processes 


fn teeretion, Chernical processes in secretion. The mode of 


race 


netivity of secretory cells. cco es bel nervous Lan 
9 


upon sceretion. Summary 


CHAPTER XIX. 


THE (NOME AND EXPENDITURE OY TIM HoDY, 


‘The material daily Joases of the Body, The daily losics of the 
Body in energy. The conservation of energy. Potential and 
kinetlcenergy. ‘The energy of chemical aflinity, The relation 
Hotween matter lost by the Body daily and the energy spent by 
it, The conditions of oxidation in the living Body. The fuel 
of the Body. Oxidation by succosslve steps. The utilization 
‘of energy in the living Body. Summary... z 


CHAPTER XX. 


yoons, 


Foods as tissueformers. The food of plants, Non-oxidizable 
foods. Definition of foods Conditions which a food must 





xii CONTENTS. 


fulfill Alimentary principles. The composition of the more 
important foods. Cooking. Alcohol. The advantage of a 
mixed diet... ..s.0.020++ Ag 


CHAPTER XXL 
‘THE ALIMENTARY CANAL AND ITS APPENDAGES 
General arrangement. The teeth. The tongue. The salivary 
glands. ‘The fauces, The pharynx, The gullet, The 
stomach. ‘Tho histology of the gastric glands, The small 
intestine, The large intestine, ‘The liver. ‘The pancreas... 308 
CHAPTER XXII. 


THE LYMPUATIC SYSTEM AND THE DOCTLESS GLANDS. 


Distribution and stracture of lymph vessels, The thoracic duct, 


‘The serous cavities, ‘The lymphatic glands, The movement 
of thelymph. The spleen, The thymus, The thyroid body. 
‘The supra-renal capsul . 4 «- 820 


CHAPTER XXII. 
DIGESTION, 


The object of digestion. Uses of saliva. Deglutition, The 
gastric juice, Gastric digestion. The chyle. The pancreatic 
secretion, Tho bilo, ‘The intestinal secretions. Intestinal di 
gestion. Absorption from the intestines, The digestion of an 
ordinary meal. Dyspepsia. canes cia 


CHAPTER XXIV. 
THE RESPIRATORY MECIANTEM. 


Detinitions. Respiratory organs, The air-pasages and Jungs. 
‘The pleura. The respiratory movements. The structure of 
the thorax. The mechanism of inspiration. Expiration. 
Forced respiration. ‘The respiratory sounds, The capacity 
of the lungs. Hygiene of respiration. The aspiration of the 
thorax, Influence of respiratory movements upon the Bow of 
blood and lymph. . 





CONTENTS. 


CHAPTER XXYV. 


TRE CHEMISTRY OF RESPIRATION. 


Nature of the problems. Changes produced in air by being once 
breathed. Ventilation. Changes undergone by blood im the 
Jungs. ‘The blood gases. Cwuses of color of arterial and 
venous blood. Laws governing the absorption of gases by 
liquids, The absorption of oxygen by the blood. Conse 
quences of the way in which oxygen is held in the blood. 
The general oxygen interchanges of the blood. The earbon 
Aioxide of the blood Internal respiration. ......-» 


CHAPTER XXVI. 


THE NERVOUS FACTORS OF TIL RESPIMATORY MECHANISM. 
ASEIYXEA, 


The respiratory centre, Is the respiratory centre reflex? The 


stimulus of the respiratory centre. The couse of the respira 
tory rhythm. The influence of the pueumogastric nerves upon 
the respiratory centre. The expiratory centre, Asphyxla. 
Carbon monoxide comes Modified respiratory move- 
MENS... ee cee ee eee 


CHAPTER XXVII 
‘THE KIDNEYS AND THE SKIN. 


‘The general arrangement of the urinary organs. The structure 
of the kidneys. The renal secretion, The mechanism of the 
renal sceretion. The function of the renal epithelium. The 
skin. Epidermis and cutis vera, Hairs, Nails. Glands of 
the skin, Relation of nerves to sweat secretion, ziviios of 
tho skin, Bathing........ 


CHAPTER XXVIII. 


NUTRITION. 


‘The problems of animal nutrition. ‘The seat of the oxidations of 
the Body. Tissue-building and energy-yielding foods ‘The 
source of the energy spent in muscular work. Luxus con: 
sumption, The antecedents of urea, Proteid starvation and 





xiv CONTENTS 


over-feeding. The storage tissues. siete Diabetes. The 


history of fata. Dietetics... 00.60. e eee AB 


CHAPTER XXIX. 


THE PRODUCTION AND REGULATION O¥ THE HEAT OF THE 
BODY. 


Cold- and warm-blooded animals. The temperature of the Body. 
‘The sources of animal heat. Energy lost by the Body in 
twenty-four hours, The superiority of the Body as a machine 
for executing mochanical work. The maintenance of an 
average temperature, Local temperatures. Thermic nerves, 


CHAPTER XXX. 
SENSATION AND KENKE-ONGANS, 


‘The subjective functions of the nervous system. Common sen: 
sation unorgans of special sense. The peripheral reference 
of sensations, Differences between sensations, ‘The easential 
structure of a sense organ. The cause vf the modality of sensa- 
tions, The psycho-physical law. Perceptions. Sensory illu- 


CHAPTER XXXIL. 
‘THE KYB AS AN OPTICAL INSTUMENTT. 


‘The essential structure of an eye. The appendages of the eye, 
‘The lachrymal apparatus. The muscles of the eyeball. The 
anatomy of the eyeball. The structure of the retina, ‘The 
rofracting media of the eye. The properties of light. Accom. 
modation, Short sight and long si Hygiene of sight, 
Optical defects of the eye, 


CHAPTER XXXIL 
‘THE EYE AS A SENSONY APPARATUS, 
‘The excitation of the visual apparatus. Idjo-retinal light. ‘The 
parts of the retina on which light directly acts. The vision 


purple. Intensity of visual sensations, Duration of Iuminous 
sensations, ‘The localizing power of the retina, Color vision, 





CONTENTS. xv 


rage 
Color blindness, Fatigue of the retina and after-images. Con 
trasts, Hering’s theory of vision. Visual perceptions. Single 
vision with two eyes. ahatans 


CHAPTER XXXIIL 


TRE RAR AND MEANING. 


The externalear, The tympanum. The auditory ossicles. The 
joternal car. The organ of Corti. The loudness, pitch, and 
timbre of sounds. Sympathetic resonance. Functions of the 
tympanic membrane, of the auditory ossicles, of the cochlea, 
and of the vestitule. Auditory perceptions. Sac 


CHAPTER XXXIV. 


TOUCH, THE TEMPERATURE SENSE, THE MUSCULAR SENRE, 
COMMON SENEATION, SMELL, AND ‘TASTE. 


Nerve-cndings in the skin. The pressure sense. The localizing 
power of the skin. ‘The temperature sense, Modality of skin 
sensations. The muscular sense, Pain. Hunger and thirst. 
Smell. Taste........ Reerrees ie séantecee tone OOD 


CHAPTER XXXV 
‘THE FUNCTIONS OF TIE MAIN AND «PINAI CORD, 


‘The special physiology of uerve-centres, The spinsl cord as a 
centre. Reflex uctions. The least-resistance hypothesis, ‘The 
education of the spinal cord. The inhibition of reflexes. Psy- 
chieal activities of the cord. The cord as a conductor of 
nervous impulses. Functions of the brain in general. Func 
Yions of medalla oblongata. Functions of cerebellum, pons 
Varolii, and mid-brain, Sensations of equilibrium and fune- 
tions of semicircular canals, Functions of the fore-brain 
Hiygiene of the brain. fy tek SR PT 

CHAPTER XXXVI 


YOIOR AND SPEECH 


Anatomy of laryox. The vocal cords, Causes of the varying 
pitel of the volre. Range of the human voice, The produ 
tion of vowels, Consonants... 





CONTENTS. 


APPENDIX. 


REPRODUCTION AND DEVELOPMENT. 


Reproduction in general. Sexual and asexual reproduction. Male 
reproductive organs. ‘emale reproductive organs. Pubert: 
Ovulation. Menstruation. Hygiene of menstruntion. Impregua- 
tion. Pregnancy. The fotal appendages ‘The intra-uterine 
nutrition of the embryo, Parturition, Lactation. Feeding of 
infants, The stages of life. Death. 





THE HUMAN BODY. 


CHAPTER IL 


THE GENERAL STRUCTURE AND COMPOSITION 
OF THE HUMAN BODY. 


Definitions. The living human Body may be considered 
from either of two aspects. Its structure may be especial- 
ly examined, and the forms, connections and mode of 
growth of its parts be studied, as also the resemblances or 
differences in such respects, which appear when it is com- 
pared with other animal bodies, Or the living Body may 
be more especially studied as an organism presenting defi- 
nite properties und performing certain actions; and then its 
parts will be investiguted with a view to discovering what 
duty, if any, each fulfills. The former group of studies 
constitutes the acience of Anatomy, and in go far as it deals 
with the human Body alone, of Human Anatomy; while 
the latter, the science concerned with the uses—or in tech- 
nical language the functions —of each part is known as 
Physiology. Closely connected with physiology is the 
science of Hygiene, which is concerned with the conditions 
which are favorable to the healthy action of the’varions 
parts of the Body ; while the a ties and structure of the 
diseased body form the subject-matters of the sciences of 
Pathology wid Pathological Anatomy. 

Tissues and Organs, Histology. Examined merely 
from the outside, our Bodies present a considerable com- 
plexity of structure. We easily recognize distinct parts as 
head, neck, trank and limbs; and in these again emaller 





2 THE HUMAN BODY. 


constituent parts, as eyes, nose, ears, mouth; arm, fore- 
arm, hand; thigh, leg and foot, We can, with such 
on external examination, go even farther and recognize 
different materials as entering into the formation of the 
larger parts, Skin, hair, nails and teeth are obviously 
different substances; simple examination by pressure 
proves that internally there are harder and softer solid 
parts; while the blood that flows from a ent finger shows 
that liquid constituents also exist in the Body. The con- 
ception of complexity, which may be thus arrived at from 
external observation of the living, is greatly extended by 
dissection of the dead Body, which makes manifest that it 
consists of a great number of diverse parts or organs, which 
in turn are built up of a limited number of materials, the 
same material often entering into the composition of many 
different organs. These primary building materials are 
known as the ¢isswes, and that branch of anatomy which 
deals with the characters of the tissues and their arrange- 
ment in various organs is known as Histology; or, since it 
is mainly carried on with the aid of the microscope, as 
Microscopic Anatomy. If, with the poet, we compare the 
Body to a house, we may go on to liken the tissuos to the 
bricks, stone, mortar, wood, iron, glass and 90 on used in 
building; and then walls and floors, stairs and windows, 
formed by the combination of these, would answer to ana- 
tomical organs. 

Zoological Position of Man, External examination of 
the human Body shows also that it presents certain re- 
semblances to the bodies of many other animals: head 
and neck, trunk and limbs, and various minor parts enter- 
ing into them, are not at all peculiar to it, Closer study 
and the investigation of internal structure demonstrates 
further that these resemblances are in many cases not su- 
perficial only, but that our Bodies may be regarded aa built 
upon a plan common to them and the bodies of many 
other creatures: and it soon becomes further apparent 
that this resemblance is greater between the human Body 
and the bodies of ordinary four-footed beasts, than between 
it and the bodies of birds, reptiles or fishes. Hence, from 





THE PRIMATES. 8 


a zoological pomt of yiew, man’s Body marks him out as 
belonging to the group of Mammalia (see Zoology), which 
includes all animals in which the female suckles the young; 
and among mammals the anatomical resemblances are 
closer and tho differences less between man and certain 
apes than between man and the other mammals; so that 
zoologists still, with Linneus, include man with the mon- 
keys and apes in one subdivision of the Mammalia, known 
asthe Primates. That civilized man is mentally far superior 
to any other animal ia no valid objection to such a classifi- 
cation, for zoological groups are defined by anatomical and 
not by physiological characters ; and mental traits, since we 
know that their manifestation depends upon the structural 
integrity of certain organs, are essentially phenomena of 
function and therefore not available for purposes of xo- 
ological arrangement. 

Man however walks eroct with the head upward, while 
the great majority of Mammals go on all fours with the 
head forward and the back upward, and various apes 
adopt intermediate positions, so in considering. corre- 
aponding parts in such cases confusion is apt to arise 
unless a precise meaning be given to such terms as “an- 
torior” and “posterior.” To avoid this difficulty anato- 
mists give these words definite arbitrary significations in 
ull cases and these we shall use in future. Tho head end 
is always anterior whatever the natural position of the 
animal, and the opposite end posterior; the belly side is 
spoken of as ventral, and the opposite side as dorsal ; right 
and left of course present no difficulty. Moreover, that 
wnd of a limb nearer the trunk is spoken of as proximal 
with reference to the other or distal end. The words 
upper and lower may be conveniently used for the relative 
position of parts in the natural standing position of the 

‘The Vortobratoe Plan of Structure. Negl 
meyely appuront differencos as arise from th 
normal posture above pointed out, we find 
zoological clase, the Mammals, differs very widely in its 
broad structural plan from the groups including sea anem- 





, 
4 THE HUMAN BODY. 


ones, insects, or oysters, but agrees in many points with 
the groups of fishes, amphibians, reptiles, and 

‘These four are therefore placed with man and all other 
Mammals in one great division of the animal kingdom 
known as the Verfebrata. The main anatomical character of 
all vertebrate animals is the presence in the trank of the 
body of two cavities, a dorsal and a ventral, separated by a 
solid partition, and in the adults of nearly all vertebrate 
animals a hard axis, the vertebral column (backbone or spine), 
develops in this partition and forms a central support for 
the rest of the body (Fig. 2, ee). The dorsal cavity is con- 
tinued through the neck, when there is one, into the head, 
and there widens out. The bony axis is also continued 
through the neck and extends into the head in a modified 
form. The ventral cavity, on the other hand, is confined 
to the trunk. It contains the main organs connected with 
the blood-flow and is thus often called the hamat cavity. 

Upon the ventral side of the head is the mouth open- 
ing leading into a tube, the alimentary canal, f, which 
passes back through the neck and trunk and opens again 
on the outside at the posterior part of the latter. In its 
passage through the trunk region this canal lies in the 
ventral cavity. 

The Mammalia. In many vertebrate animals the ven- 
tral cavity is not subdivided, but in the Mammalia it is; a 
membranous transverse partition, the midriff or diaphragm 
(Fig. 1, 2), separating it into an anterior chest or thoracic 
cavity, and a posterior or abdominal cavity. The alimen- 
tary canal and whatever else passes from one of these cayi- 
ties to the other must therefore perforate the diaphragm. 

In the chest, besides part of the alimentary canal, lie 
important organs, the heart, h, and lungs, iw, the heart 
being on the yentral side of the alimentary canal. The 
abdominal cavity is mainly occupied by the alimentary 
canal and organs connected with it and concerned in the 
digestion of food, as the stomach, ma, the liver, le, the 
pancreas and the intestines. Among the other more prom- 
inent organs in it are the &idneys and the spleen. 

In the dorsal cavity lie soft white organs, the drain and 





THE MAMMALIAN TYPE. 5 


spinal cord, the former occupying its anterior enlargement 
im the head. Brain and spinal cord together form the 

inal nervous centre, but in addition to this there 
are found in the ventral cavity a number of small nerve cen- 


Pio. f The Hoty opened from the trout to show the contents of its ventral 


‘thos united together by connecting cords, and with thoir 
offshoots forming the sympathetic nervous system. 
"The walls of the three main cayitiesare lined by smooth, 


— 





THE HUMAN BODY, 


moist serous membranes. That lining the dorsal cavity 
is the arachnoid ; that lining the chest the plewra; that 


Tro, %.—Dingrammatio erat 
tudinal seotlor ot the vody. 
e neural tube, with Ite appr 
enlargement in the skull eavit 
St ae, the apinal cord: 
the brainy eq vertétire form 
Sng the solid partition between 
‘the dorsal nui 
&, the pleural, and ¢, the abot 
ftial divisions of the ventral 
Sepa 
by’ the diaphragm 
haaal, and, the month 
ber, Opening behind into 
barynx. from 


lining the abdomen the perito- 
neum ; the abdominal cavity is in 
consequence often culled the per- 
itoneal cavity. Externally the 
walls of these cavities are covered 
by the skin, which consists of two 
layers : an outer horny layer called 
the epidermis, which is constantly 
being shed on the surface and re- 
newed from below ; and a deeper 
layer, called the dermis and con- 
taining blood, which the epider- 
mis does not. Between the skin 
and the lining serous membranes 
are bones, muscles (the lean of 
meat), and a great number of 
other structures which we shall 
have to consider hereafter. All 
cavities inside the body, as the 
alimentary canal and the air pas- 
sages, which open directly or indi- 
rectly on the surface are lined by 
soft and moist prolongations of 
the skin known as mucons mem~ 
branes. In these the same two 


o, layers are found as in the skin, 


but the superficial bloodless one 
is called epithelium and the deep- 
er one the corium, 
Diagrammatically we may rep- 
resent the human Body in longi- 
tudinal section as in Fig. 2, where 
aa’ is the dorsal or neural cavity, 


; and & and ¢, respectively, the 


nm 
sch, f, the intestinal tube leads: 
Uurdugh the abdominal eavity Lo 
the peaterior opumning of the all 
amentary canal 


thoracic and abdominal subdivi- 
sions of the ventral cavity; @ rep- 
resents the diaphragm separating 





OROSS-SECTION OF THE BODY. 7 


them; ¢s is the vertebral column with its modified prolon- 
gation into the head beneath the anterior enlargement of 
the dorsal cavity; / is the alimentary canal opening in front 
through the nose, #, and mouth, o; / is the heart, 7 4 lung, 
# the sympathetic nervous system, and & a kidney. 

A transverse section through the chest is represented 
diagrammatically in Fig. 8, where x is the neural canal 
containing the spinal cord. In the thoracic cavity are seen 
the heart, 4, the lungs, 1, part of the alimentary canal, a, 
and the sympathetic nerve centres, sy; the dotted line on 
each side covering the inside of the chest wall and the 
outside of the lung represents the plewra, 


section across the Rod 

the spinal cord: the bi 
nerves i funge: tho dotted ines around. thea os 
plearee; r7, ribs; sf, the breastbono,” 


Sections through corresponding parts of any other Mam- 
mal would agree in all essential points with those repre- 
sented in Figs. 2 and 3. 

Tho Limbs. The limbs present no such arrangement of 
eayities on each side of a bony axis as is seen in the trunk, 
‘They have an axis formed at different parts of one or more 
bones (as seen at U and FR in Fig. 4, which represents 
# cross-section of the forearm near the elbow joint), but 
around this are closely packed soft parts, chiefly muscles, 
find the whole is enveloped in skin, ‘The only cavities in 
the limbs are branching tubes which are filled with liquids 

during life, either blood or a watery-looking fluid known as 
lymph. These tubes, the blood and Iymph vessels respec 





8 THE HUMAN BODY. 


tively, are not however characteristic of the limbs, for they 
are present in abundance in the dorsal and yentral cavities 


forearm a short distance below the elbow 
the radius and ulna: the epidermis, tod rate aod 


+, the latter Is continuous below wit 


les, which ee ae 


Chomicat Composition of the Body. In addition to the” 
study of the Body as composed of tissues and organs which 
are optically recognizable, we may consider it as composed 
of a number of different chemical substances. This branch 
of knowledge, which is still very incomplete, really presents 
two classes of problems. On the one hand we may limit 
ourselves to the examination of the chemical substances 
which exist in or may be derived from the dead Body, or, 
if such a thing were possible, from the living Body entirely 
at rest; such a study is essentially one of structure and 
may be called Chemical Anatomy. But aa long as the 
Body is alive it is the seat of constant chemical trans- 
formations in its material, and these are inseparably con- 
nected with its functions, the great majority of which are 
in the long-run dependent upon chemical changes. From 
this point of view, then, the chemical study of the Body 
presents physiological problems, and it is usual to include 
all the known facts as to the chemical composition and 
metamorphoses of living matter under the name of Physio~ 
logical Chemistry. Yor the present we may confine our- 
selyes to the more important substances derived from or 
known to exist in the Body, leaving questions concerning the 
chemical changes taking place within it for consideration 
along with those functions which are performed in connec- 
tion with them. 





CHEMISTRY OF THE BODY. 9 


Elements Composing the Body. Of the elements known 
to chemists only sixteen have been found to take part in 
the formation of the human Body. ‘These are carbon, hy- 
drogen, nitrogen, oxygen, sulphur, phosphorus, chlorine, 
fluorine, silicon, sodium, potassium, lithium, calcium, 
Magnesium, iron, and manganese. Copper and lead have 
sometimes been found in small quantities but are probably 
accidental and occasional. 

Uncombined Elements. Only a very small number of 
the above elements exist in the body uncombined. O-rygen 
is found in small quantity dissolved in the blood; but even 
there most of it is in a state of loose chemical combination. 
It is algo found in the cavities of the lungs and alimentary 
canal, bejng derived from the inspired air or swallowed 
with food and saliva; but while contained in these spaces 
it can hardly be said to form a part of the Body. Nitro- 
gen also exists uncombined in the Iungs and alimentary 
canal, and in small quantity in solution in the blood. Free 
Aydvogen has also beon found in the alimentary canal, be- 
ing there evolved by the fermentation of certain foods. 

Chomical Compounds. ‘The number of these which 
may be obtained from the Body is very great; but with re- 
gard to yery many of them we do not know that the form 
in which we extract them is really that in which the ele- 
ments they contain were united while in the living Body: 
since the methods of chemical analysis are such as always 
break down the more complex forms of living matter and 
leave us only its dédris for examination. We know in 
fact, tolerably accurately, what compounds enter the Body 
as food and what finally leave it as waste; but the inter- 
mediate conditions of the elements contained in these com- 
pounds during their sojourn inside the Body we know very 
little about; more especially their state of combination dur- 
ing that part of their stay when they do not exist dissolved 
in the bodily liquids, but form part of a solid living 
tissue, 


For present purposes the chemical compounds existing 
in or derived from the Body may be classified as organic 





10 THE HUMAN BODY. 


and inorganic, and the former be subdivided into those 
which contain nitrogen and those which do not. 

Witrogenous or Azotized Organic Compounds. These 
fall into several main groups: proteids, peplones, albu- 
minoids, crystalline substances, and coloring matters. 

Proteids are by far the most characteristic substances ob- 
tained from the Body, since they are only known as exist- 
ing in or derived from living things, either animals or 
plants. The type of this class of bodies may be found in 
the white of an egg, where it is stored up as food for 
the developing chick; from this typical form, which is 
called egy aliwmin, the proteids in general are often ealled 
aléuminous bodies. Each of them contains carbon, hydro- 
gen, oxygen, sulphur, and nitrogen united to form # very 
complex molecule, and although different members of the 
family differ from one another in minor points they all 
agree in their broad features and have a similar percentage 
composition, The latter in different examples appears to - 
vary within the following limits, but it is almost impossible 
to got any one of them pure for analysis: 


to 5A per cent, 


Sulphur... Mg : O8to 20“ 


Proteida are recognized by tho following characters: 1, 
Boiled, either in the solid state or in solution, with strong 
nitric acid they give a yellow liquid which becomes orange 
on neutralization with ammonia. This is the xantho-proteie 
test. 

2. Boiled with a solution containing submitrate and per- 
nitrate of merenry they give a pink precipitate, or, if in 
very small quantity, a pink-colored solution. This is 
known us Millon's fest. 

8. If a solution containing a proteid be acidulated with 
strong acetic acid und be boiled after the addition of an 
equal bulk of a saturated watery solution of sodium sul- 
phate, the proteid will be precipitated. 





PROTEIDS. PEPTONES. 1 


Among the more important proteids obtained from the © 
human Body are the following: 

Serum albumin. This exists in solution in the blood and 
is very like egg albumin in its properties. It is coagulated 
(like the white of an‘egz) when boiled, and then passes 
into the state of comgulated proteid which is, unlike the 
original serum albumin, insoluble in dilute acids or alka- 
lies or in water containing neutral salts in solution. All 
other proteids can by appropriate treatment be turned into 
coagulated proteid. 

Fibrin. This forms in blood when it ** clots,” either in- 
side or outside of the body. It is mado by the interaction 
of two other proteids known as fibrinogen and fibrinoplastin. 
Tt is insoluble in water. 

Myosin. This is derived from the muscles, in which it 
develops and solidifies after death, causing the “‘death- 
stiffening.” 

Globulin exists in the red globules of the blood and dis- 
solved in some other liquids of the body. In the blood 
corpuscles it is combined with a colored substance to form 
Aamoglobin, which is crystallizable. 

Casein is found in milk. It is insoluble in water but 
soluble in dilute acids and alkalies. Its solutions, unlike 
those of fibrin or myosin, do not coagulate spontaneously, 
or like that of seram albumin on boiling. In the milk it 
is hold in solution by the free alkali present; whon milk be- 
comes sour this is neutralized and the casein is precipitated 
a3 the ‘‘curd.” Cheese consists mainly of casein. 

Peptones. These are formed in the alimentary canal 
by the action of some of the digestive liquids upon the 
proteids swallowed as food. They contain the same elements 
as the proteids and give the xantho-proteic and Millon’s 
reactions, but are not precipitated by boiling with acetic 
acid and sodium sulphate. heir great distinctive charac- 
ter is however their diffusibility. The proteids proper will 
not dialyze (see Physics), but the peptones in solution puss 
readily through moist animal membranes. 

Albuminoids. These contain carbon, hydrogen, oxy- 
gen and nitrogen, but rarely any sulphur. Like the 





12 THE HUMAN BODY. 


proteids, the nearest chemical allies of which they seem 
to be, they are only known in or derived from living 
beings. Gelatin, obtained from bones and ligaments by 
boiling, is a typical albuminoid; as is chondrin, which is 
obtained similarly from gristle. Mucin, which gives their 
glairy tenacious character to the secretions of the mouth 
and nose, is another albuminoid. 

Crystalline Nitrogonous Substances. These are a 
heterogencons group, the great majority of them being 
materials which have done their work in the Body and are 
about to be got rid of. Nitrogen enters the Body in foods 
for the most part in the chemically complex form of some 
proteid. In the vital processes these proteids are broken 
down into simpler substances; their carbon being partly 
combined with oxygen and passed out through the lungs 
as carbon dioxide; their hydrogen is similarly in large part 
combined with oxygen and passed out as water; while their 
nitrogen, with some carbon and hydrogen and oxygen, is 
usually passed out in the form of a crystalline compound, 
containing what chemists call an “ammonium residue.” 


co 
Of these the most important is urea (Carbamide = N), 


which is eliminated through the kidneys, Urie acid is an- 
other nitrogenons waste product, and many others, such as 
kreatin and kreatinin, seem to be intermediate stages be- 
tween the proteids which enter the body and the urea and 
uric acid which leave it. 

In the bile or gull, two crystallizable nitrogen-contain- 
ing bodies, glycocholic and taurocholic acids, are found com- 
bined with soda. 

Nitrogonous Coloring Matters, These form an arti- 
ficial group whose constitution and origin is ill known. 
Among the most important are the following: 

_Homatin, derived from the red corpuscles of the blood 
in which a residue of it is combined with a proteid residue 
to form hemoglobin. 

Bilirubin aud bdiliverdin, which exist in the bile; the 
former predominating in the bile of mun wnd of carnivo- 





FATS, CARBOHYDRATES. 18 


rons animals and giving it a reddish yellow color, while 
biliverdin predominates in the bile of Herbivora which is 


green. 

Non-Nitrogenous Organic Compounds. ‘These may 
be conveniently grouped as hydrocarbons or fatty bodies; 
carbohydrates or amyloids ; aud certain non-azotized acids. 

Pats. The fats all contain carbon, hydrogen and oxygen, 
the oxygen being present in small proportion as compared 
with the hydrogen. Three fats occur in the body in large 
quantities, viz.: palmatin (CuH.O.), stearin (CorHs100,), 
and olein (CyH.0,). The two former when pure are 
solid at the temperature of the Body, but in it are mixed 
with olein (which is liquid) in such proportions as to be 
kept finid. The total quantity of fats in the Body is sub- 
ject to great variations, but its average quantity in a man 
weighing 75 kilograms (165 pounds) is wane 2.75 kilo- 
grams (6 pounds). 

Each of these fats when heated with a counutio alkali, in 
the presence of water, breaks up into a fatty acid (stearic, 
palmitic, or oleic as the case may be) and glycerine. The 
fatty acid unites with the alkali present to form a soap. 

Carbohydrates. ‘These also contain carbon, hydrogen 
and oxygen, but there is one atom of oxygen present for 
every two of hydrogon in tho molecule of each of them. 
Chemically they are related to starch. ‘The more impor- 
tant of them found in the Body are the following: 

Glycogen (C.H,.0,) found in large quantities in the 
liver, where it seems to be a reserve of material answering 
to the starch stored up by many plants. It exists in smaller 
quantities in the muscles. 

Glucose, or grape sugar (O,H,,0,), which exists in the 
liver in small quantities; also in the blood and lymph. 
Tt is largely derived from glycogen which is very readily 
converted into it. . 

Tnosit, or muscle sugar (0.1).0,4-2H,0), found in 
muscles, liver, spleen, kidneys, ete. 

Lactose, or sugar of milk (C,.H,,0,, ++ H,0), found in 
considerable quantity in milk. 

Organic Non-Nitrogonous Acids, Of these the most 





ote THE HUMAN BODY. 


important is carbonic dioxide (CO*), which is the form in 
which by far the greater part of the carbon taken into the 
Body ultimately leaves it. United with caleiam it is found 
in the bones and teeth in large proportion. 

Formic, Acetic, and Butyric acids also are found in the 
Body; stearic, palmitic, and oleie have been above men- 
tioned as obtainable from fats. Lactic acid is found in the 
stomach and develops in milk when it turns sour, A body 
of the same percentage composition, C;H.Os (sarcolac~ 
tic acid), is formed in muzcles when they work or die. 

Glycero-phosphoric acid (C5H,PO,) is obtained on the 
decomposition of Jecithin, a complex nitrogenous fat found 
in nervous tissue. 

Inorganic Constituents. Of the simpler substances en- 
tering into the structure of the body the following are the 
most important: 

Water ; in all the tissues in greater or less proportion 
and forming about two thirds of the weight of the whole 
Body, A man weighing 75 kilos (165 lbs.), if completely 
dried would therefore lose about 50 kilos (110 Tbs.) from the 
evaporation of water. Of the constituents of the Body the 
enamel of the teeth contains least water (about two per 
cent) and the saliva most (about 99.5 per cent); between 
these extremes are all intermediate steps—bones containing 
about 22 per cent, muscles 75, blood 79. 

Common salt—Sodium chioride—(NaC)) ; found in all 
the tissues and liqnids, and in many cases playing an 
important part in keeping other substances in solution in 
water. 

Potassium chioride(KCl); in the blood, muscles, nerves, 
and most liquide. 

Calcium phosphate (Ox.2PO,); in the bones and teeth in 
large quantity. In less proportion in all the other tissues. 

Besides the above, ammonium chloride, sodium and 
potassium phosphates, magnesium phosphate, sodium sul- 
phate, potassium sulphate and calcium fluoride have been 
obtained from the body. 

Uncombined Hydrochloric acid (HCl) is found in the 
stomach, 





CHAPTER II. 


THE FUNDAMENTAL PHYSIOLOGICAL 
ACTIONS, 


The Properties of the Living Body. When we turn 
from the structure and composition of the living Body to 
consider its powers and properties we meet with the same 
variety and complexity, the most superficial examination 
being sufficient to show that its parts are endowed with very 
different faculties. Light falling on the eye arouses in us 
@ sensation of sight but falling on the skin has no such 
effect; pinching the skin causes pain, but pinching a hair 
or a nail does not: when the ears are stopped, sounds 
arouse in us no sensation; we readily recognize, too, hard 
parts formed for support, joints to admit of movements, 
apertures to receive food and others to got rid of wastes, 
We thus perceive that different organs of our Bodies have 
very different endowments and serve for very distinct pur- 
poses; and here again the study of internal organs shows 
us that the vurieties of quality observed on the exterior are 
tnt slight indications of differences of property which per- 
yade the whole, being sometimes dependent on the specific 
characters of the tissues concerned and sometimes upon the 
manner in which these are combined to form various 
organs. Some tissues are solid, rigid and of constant 
shape, as those composing the bones and teeth; others, as 
the muscles, are soft and capable of changing their form; 
and still others are capable of working chemical changes 
by which such peculiar fluids as the bile or the saliva are 
produced. We find elsewhere a number of tissues com- 
bined to form a tube adapted to receive food and carry it 
through the Body for digestion, and again similar tissues 





16 THE HUMAN BODY. 


differently arranged to receive the air which we breathe-in, 
and expel after abstracting from it part of its oxygen and 
widing to it certain other things; and in the heart and 
blood-vessels we find almost the same tissues arranged to 
propel and carry the blood over the whole Body. The 
working of the Body offers clearly even a more complex 
subject of study than its structure. 

Physiological Properties. In common with inanimate 
objects the Body possesses many merely physical properties, 
as weight, rigidity, elasticity, color, and so on; but in ad- 
dition to these we find in it while alive many others 
which it ceases to manifest at death. Of these perhaps 
the power of executing spontaneous movements and of 
maintaining a high bodily temperature are the most 
marked. As long as the Body is alive it is warm and, 
since the surrounding air is nearly always cooler, must be 
losing heat all day long to neighboring objects; neverthe- 
Joss we are at the end of the day as warm as at the begin- 
ning, the temperature of the Body in health not varying 
much from 37.5° ©. (99° F.), so that clearly our Bodies 
must be making heat somehow all the time. After death this 
production of heat ceases and the Body cools down to the 
temperature in its neighborhood; but so closely do we 
associate with it the idea of warmth that the sensation 
experienced in touching a corpse produces so powerful 
an impression as commonly to be described as icy cold. 
The other great characteristic of the living Body is its 
power of executing movements; so long as life lasts it is 
never at rest; even in the deepost slumber the regular 
breathing, the tap of the heart against the chest-wall, and 
the beat of the pulse tell us that we are watching sleep and 
not death. If to this we add the possession of conscions- 
ness by the living Body, whether aroused by forces im- 
mediately acting upon sense-orguns or not, we might de- 
scribe it as a heat-producing, moving, conscious organism. 

The production of heat in the Body needs fuel of 
some kind as much as its production ii ire; and every 
time we move ourselves or external objects some of the 
Body is used up to supply the necessary working power, just 





Ww 


as some coals are burnt in the furnace of an engine for 
every bit of work it does; in the same way every thought 
that arises in us is accompanied with the destruction of 
some part of the Body. Hence these primary actions of 
keeping warm, moving, and being conscious necessitate 
many others for the supply of new materials to the tis- 
Suet concerned and for the removal of their wastes; still 
others are necessary to regulate the production and loss of 
heat in accordance with changes in the exterior tempera- 
ture, to bring the moving tissues into relation with the 
thinking, and so on. By such subsidiary arrangements 
the working of the whole Body becomes so complex that it 
woul fill many pages merely to enumerate what is known 
of the duties of its various parts. However, all the proper 
Physiological properties depend in ultimate analysis on a 
small number of faculties which are possessed by all living 
things, their great variety in the human Body depending 
upon special development and combination in different 
tissues and organs; and before attempting to study them in 
their most complex forms it is advantageous 
to examine them in their simplest and most 
generalized manifestations as exhibited by 
some of the lowest living things or by the 
simplest constituents of our own Bodies. 

Colls, Among the anatomical elements 
which the histologist mocts with as entering 
into the composition of the human Body 
are minute granular masses of a soft con- 
sistence, about 0.012 millimeter (gytyg of an 
inch) in diameter (Fig. 5, e). Imbedded in 
each lies a central portion, not granular 
and therefore different in appearance from 
the rest. These anatomical units are 
as cell, the granular substance being th 
call body and the imbedded clearer portion 
the cell nucleus. Inside the nuclous may often be distin- 


as the white blood poael ‘and ‘eioi ‘exhibits of itself 





18 THE HUMAN BODY. 


certain properties which are distinctive of all living things 
a5 compared with inanimate objects, 

Coll Growth. In the first place, each such cell can take 
np materials from its ontside and build them up into its 
own peculiar substance; and this does not oceur by the 
deposit of new layers of material like its own on the surface 
of the cell (as a crystal might increase in an evaporating 
solution of the same salt) but in an entirely different way, 
The cell takes up chemical elements, either free or com- 
bined in a manner different from that in which they exist 
in its own living eubstance, and works chemical changes 
in them by which they are made into part and parcel of 
itself. Moreover, the new material thus formed is not de- 
posited, at any rate necessarily or always, on the surface 
of the old, but is laid down in the substance of the already 
existing cell among its constituent molecules. The new- 
formed molecules therefore contribute to the growth of the 
cell not by superficial accretion, but by interstitial deposit 
or infussusception. 

Cell Division. The increase of size, which may be 
brought about in the above manner, is not indefinite, but 
is limited in two ways. Alongside of the formation and 
deposit of new material there occurs always in the living 
cell a breaking down and elimination of the old; and when 
this process equals the accumulation of new material, as it 
does in all the cells of the Body when they attain a certain 
size, growth of course ceases. In fact the work of the cell in- 
creases as its mass, and therefore as the cube of its diame- 


Fro, 6.—A white blood corpusclo dividing, ax observed at auccessive intervals 
of a few seconds with the microscope. 


ter; while the receptive powers, dependent primarily upon 
the superficial area, only increase as the square of the di- 
ameter. The breaking down in the cell increases when its 





ASSIMILATION. 19 


work does and so at last equals the reception and constrnc- 
tion. The second limitation to indefinite growth is con- 
nected with the power of the cell to give rise to new cells 
like itself. Under certain circumstances, which are not 
well known, the cell may become narrowed (Fig. 6) at one 
zone; the constriction deepens until the parts on each side 
of it are merely united by a narrow band which finally 
gives way and two cells are formed, euch like the parent 
but for its smaller size; or the cell may divide into two or 
more by flat surfaces of separation, or in 
a way intermediate between this mode 
and the last (Fig. 7). Insome cases new oO @e 
cells form in the interior of the old and 
are then set free from it. ‘The new cells 6O fo) 2) 
in these ways grow as the origi- Ba eatin 

nal cell did, and may in turn multiply in medeet oe dieision, 
the same manner. Very commonly the faci tne mean 
nucleus divides before the rest of the furrows in mctan 
cell, andits parts then form the nucle) of 22ne.ant finally. te 
the new cells. a ee 

Assimilation: Reproduction. These "™* 
two powers, that of working up into their 
own substance materials derived from outside, known as 
assimilation, and that of, in one way or another, giving rise 
to new beings like themselves, known as reproduction, are 
possessed by all kinds of living beings, whether animals or 
plants. ‘There is, however, this important difference be- 
tween the two: the power of assimilation is necessary for 
the maintenance of each individual cell, plant, or animal, 
sinee the already existing living material is constantly 
breaking down and being removed as long as life Insts, and 
the loss must be made good if each is to continue its exist- 
ence. The power of reproduction, on the other hand, is 
necessary only for the continuance of the or race, and 
need be, und often is, possessed y he indi- 
yiduals composing it. Wor! ‘ example, cannot 
reproduce their kind, that duty being left to the queen-bee 
and the drones of cach hive. 

The breaking down of already existing chemical com- 





THE HUMAN BODY. 


pounds into simpler ones, sometimes called disassimélation, 
is as invariable in living beings as the building up of new 
complex molecules referred to above. It is associated with 
the assumption of uncombined oxygen from the exterior, 
which is then combined directly or indirectly with 
other elements in the cell, as for example carbon, 
giving rise to carbon dioxide, or hydrogen producing 
water. In this way the molecule in which the carbon and 
hydrogen previously existed is broken down, and at the 
same time energy is liberated, which in all cases seems to 
take in part the form of heat just as when coal is burnt 
ina fire, but may be used in part for other purposes such as 
producing movements. ‘The carbon dioxide is usually got 
rid of by the same mechanism as that which serves to take 
up the oxygen, and these two processes constitute the 
function “of respiration which occurs in all living things. 
Assimilation and disassimilation, going on side by side and 
being to a certain extent correlative, are often spoken of 
together as the process of nufrition, a term which there- 
fore includes all the chemical transformations occurring in 
living matter, 

Contractility. Nutrition and (with the above-mentioned 
partial exception) reproduction characterize all living crea- 
tures; and both faculties are possessed by the simple 
nucleated cells already referred to as found in our blood. 
But these cells poscess also certain other properties which, 
although not so absolutely diagnostic, are yet very charac- 
teristic of living things. 

Examined carefully with a microscope in a fresh-drawn 
drop of blood, they exhibit changes of form independent 
of any pressure which might distort them or otherwise 
mechanically alter their shape. These changes may some- 
times show themselves as constrictions ultimately leading 
to the division of the cell; but more commonly(Fig. 12*) 
they have no such result, the cell simply altering its form 
by drawing in its substance at one point and thrusting it 
out at another, The portion thus protruded may in tarn 
be drawn in and a process be thrown out elsewhere ; or the 
rest of the cell may collect around id a fresh protru- 


Zz *P. 43, 





IRRITABILITY. 


sion be then made in the same side; and by repeating this 
‘manuuyre these cells may change their place and creep 
across the field of the microscope. Such changes of form 
from their close resemblance to those exhibited by the micro- 
scopic animal known as the Ameba (see Zoology) are called 
amueboid, and the faculty in the living cell upon which they 
depend is known in physiology as contractility. It must 
be borne in mind that physiological contractility in this 
sense is quite different from the so-called contractility of 
a stretched indian-rubber band, which merely tends to re- 
assume a form from which it has previously been forcibly 
removed. 

Irritability. Another property exhibited by these blood- 
cells is known as irritability. An Amoeba coming into 
contact with a solid particle calculated to serve it as food 
will throw around it processes of its substance, and grad- 
nally carry the foreign mass into its own body. The 
amount of energy expended by the animal under these 
circumstances is altogether disproportionate to the force of 
the external contact. It is not that the swallowed mass 
pushes in mechanically the surface of the Amoeba, or bur- 
rows into it, but the mere touch arouses in the animal an 
activity quite disproportionate to the exciting force, and 
comparable to that set free by a spark falling into gunpow- 
der or by a slight tap on a piece of gun-cotton. It is this 
disproportion between the excitant (known in Physiology as 
a stimulus) and the result, which is the essential character- 
istic of irrifadility when the term is used in a physiological 
connection. The granular cells of the blood can take 
foreign matters into themselves in exactly the same man- 
ner as an Amoba does; and in this and in other ways, as 
by contracting into rigid spheres under the influence of 
electrical shocks, they show that they also are endowed 
with irritability. 

Conductivity. Further, when an Amebaor one of these 
blood-cells comes into contact with a foreign body and 
proceeds to draw it into its own substance, the activity ex- 
cited ix not merely displayed by the parts dctually touched. 

_ Distant parts of the cell also co-operate, so that the influ- 





22 THE HUMAN BODY. 


ence of the stimulus is not local only, but in consequence 
of it a change is brought about in other parts, arousing 
them, ‘This property of transmitting disturbances is known 
as conductivity. 

Finally, the movements excited are not, as a rule, ran- 
dom. They are not irregular convulsions, but are adapted 
to attain a certain end, being so combined as to bring the 
external particle into the interior of the cell. This capa- 
city of all the parts to work together in definite strength 
and sequence, to fulfil some purpose, is known as co-ordi- 
nation. 

‘These Properties Characteristic but not 
These four faculties, irritability, conductivity, contractility, 
and ¢o-ordination, are possessed in a high degree by our 
Bodies us uwhole. If the inside of the nose be tickled with 
4& feather, a sneeze will be produced. Here the feather- 
touch (stimudws) has called forth moyements which are 
mechanically altogether disproportionate to the energy of 
the contact, so that the living body is clearly irritable. 
‘The movements, which are themselves a manifestation of 
contractility, are not exhibited at the point touched, but at 
more or less distant parts, among which those of abdomen, 
chest, and face are visible from the exterior; our Bodies 
therefore possess physiological conductivity. And finally 
these movements are not random, but combined so as to 
produce a violent current of air through the nose tending 
to remove the irritating object; and in this we have a 
manifestation of co-ordination. Speaking broadly, these 
properties are more manifest in animals than in plants, 
though they are by no means absolutely confined to the 
former. In the sensitive plant touching one leaflet will 
excite regular movements of the whole leaf, and many of 
the lower aquatic plants exhibit movements as active as 
those of animals, On the other hand, no one of these four 
faculties is absolutely distinctive of living things in the 
way that growth by intussusception and reproduction are. 
Irritability is but a name for unstable molecular equilibrium, 
and is as marked ‘in nitroglycerine as in any living cells; in 
the telephone the influence of the voice is conducted as a 





SPONTANEITY, 23 


molecular change along a wire, and produces results at a 
distance; and many inanimate machines afford examples of 
the co-ordination of movements for the attainment of 
definite ends. 

Spontansity. There is, however, one character belonging 
to many of the movements exhibited by ameboid cells, in 
which they appear at first sight to differ fundamentally 
from the movements of inanimate objects. This character 
is their apparent spontaneity or automaticity, The cells 
frequently change their form independently of any re- 
eognizable external cause, while a dead mass at rest and 
unacted on from outside remains at rest. This difference 
is, however, only apparent and depends not upon any faculty 
of spontaneous action peculiar to the living cell, but upon 
its nutritive powers. It can be proved that any system of 
material particles in equilibrium and at rest will forever 
remain so if not acted upon by an external force, Such a 
system can carry on, under certain conditions, a series of 
changes when once a start has been given; but it cannot 
initiate them itself. Each living cell in the long-run is but 
# complex aggregate of molecules, composed in their turn 
of chemical elements, and if we suppose this whole set of 
atoms at rest in equilibrium at any moment, no change can 
be started in the cell from inside; in other words, it will 
possess no real spontaneity, When, however, we consider 
the irritability of amaboid cells, or, expressed in mechanical 
terms, the unstable equilibrium of their particles, it be- 
comes obyious that a very slight external cause, such a8 
may entirely elude our observation, may serve to set going 
in them 4 very marked series of changes, just as pulling 
the trigger will fire off a gun. eq ilibriam of 
the cell has been disturbed, move 
its constituent molecules or of i will continue 
wntil all the molecules have agai 1 nto a stable 
state. But in living cells the 3 i 
commonly indefinitely postponed by 
particles, food i in one n or ‘another, from the exterior. 

ited by the rest 
ing state into which someof the lower animals, as the wheel 





od THE HUMAN BODY. 


animalcules, pass when dried slowly at a low temperature: 
the drying acting by checking the nutritive 
which would otherwise have prevented the reattainment 
of molecular equilibrinm. All signs of movement or other 
change disappear under these circumstances, but as soon 
we water again soaks into their substance and disturbs the 
existing condition, then the so-called “ spontaneous” moye- 
ments recommence. If, therefore, we use the term spon- 
taneity to express a power in a resting system of particles of 
initiating changes in itself, it is possessed neither by living 
nornot-living things, But if we simply employ it to desig- 
nate changes whose primary cause we do not recognize, and 
which cause was in many cases long antecedent to the 
changes which we sce, then the term is unobjectionable and 
convenient, as it serves to express briefly a phenomenon 
presented by many living things and finding its highest 
manifestation in many human actions. It then, how- 
evor, no longer designates a property peculiar to them. A 
steam-engine with its furnace lighted and water in its 
boiler may be set in motion by opening a valve, and the 
movements thus started will continue spontancously, in the 
above sense, until the coals or water are used up. The dif- 
ference between it and the living cell lies not in any spon- 
taneity.of the latter, but in its nutritive powers, which 
enable it to replace continually what answers to the coals 
and water of the engine. 

Protoplasm, Finding all those properties possessed by 
4 simple nucleated cell, we are naturally led to inquire upon 
what part of it do they depend? It is clear that if they are 
exhibited in the absence of any one it cannot be essen- 
tial to their manifestation. Now a study of the lower 
forms of life shows us that these powers are independent of 
the cell nucleus, since we find them all exhibited by cells in 
which the nucleus is wanting. Moreover, in many cases 
not only the nucleus but all granules are absent, and yet we 
find the remaining masz nutri productive, irritable, 
contractile, conductive, co-ordinative, and antomatic. We 
are thus driven to conclude that in the case of the granular 
blood-cella, these faculties are most probably endowments 





PROTOPLASM. 


of the transparent portions of the cell body, in which the 
granules lie imbedded. his, the really working part of the 
cell, is known as the cell protoplasm. ‘The réle of the 
nucleus and granules so often present is not yet well 
underatood; possibly the granules in many cases represent 
incompletely assimilated food. 

What the actual chemical constitution of protoplasm is 
we do not know, but it is one of great complexity, All 
methods of chemical analysis destroy it, and what we analyze 
is not protoplasm, which is always alive—which is a form 
of matter endowed with those properties which we call 
yital—bnt a mixture of the products of its decomposition 
when it ceases to live. Such amixture is often called dead 
protoplasm, but the phrase is objectionable as implying a 
contradiction. Wherever there is protoplasm there is life, 
and wherever we meet with life we find protoplasm, so that 
it has been called the ‘* physical basis of life.” The name 
protoplasm, too, is rather to be regarded as a general term 
for a number of closely allied substances agreeing with one 
another chemically in main points, as the proteids do, but 
differing in minor details, in consequence of which one cell 
differs slightly from another in faculty. On proximate 
analysis every mass of protoplasm is found to contain much 
water and acertain amount of mineral salts; the water 
being in part constitwent or entering into the structure of 
the molecules of protoplasm, and in part probably deposited 
in layers between them. Of organic constituents proto- 
plasm always yields one or more proteids, some fats, and 
some starchy or saccharine body. So that the original 

lasm is probably to be regarded as containing chemi- 
eal “residues” of proteids, fats, and cArbohydrates, com- 
bined with salts and water. 

The Fundamental Physiological Properties, All living 
animals possess in greater or less degree the properties con- 
sidered in this chapter; and since the science of physiology 
ig yirtually concerned with considering how these proper- 
ties are acquired, maintained, and manifested, and for 
what ends they are employed, we may call them the funda- 
mental physiological properties. 





CHAPTER III. 


THE DIFFERENTIATION OF THE TISSUES AND 
THE PHYSIOLOGICAL DIVISION OF EMPLOY- 
MENTS. 


Development. Every human Body commences its indi- 
vidual existence as a single nucleated cell. This cell, 
known as the ovwm, divides or segments and gives rise to 


= 
ae 5 
D z 


Fro. §—A, an ovum: B to E successive stages in its segmentation until the 
morula, F. % produced. , 


a mass consisting of a number of similar units and called 
the mulberry mass or the morula. At this period then, 
long before birth, there are no distinguishable tissues en- 
tering into the structure of the Body, nor are any organs 
recognizable. 

For a short time the morula increases in size by the 
growth and division of its cells, but very soon new pro- 
cesses occur which ultimately give rise to the complex 





DIVISION OF LABOR, at 


adult body with its many tissues and organs. Groups of 
cells ceasing to grow and multiply like their parents begin 
to grow in ways peculiar to themselves, and so come to 
‘differ both from the original cells of the morula and from 
the cells of other groups, and this unlikeness becoming 
more and more marked, a varied whole is finally built up 
from one originally alike in all its parts. Peculiar growth 
of this kind, forming a complex from a simple whole, is 
called development; and the process itself in this case iz 
known as the differentiation of the tissues, since by it they 
are, 80 to speak, separated or specialized from the general 
mass of mother-cells forming the mornla. 

As the differences in the form and structure of the con- 
stituent cells of the morula become marked, differences in 
property arise, and it becomes obvious that the whole cell 
aggregate is not destined to give rise to a collection of in- 
dependent living things, but to form a single human being, 
in whom each part, while maintaining its own life, shall 
haye duties to perform for the good of the whole. In other 
words, a single compound individual is to be built up by 
the union and co-operation of 1 number of simple ones 
represented by the various cells, each of which thenceforth, 
while primarily looking after its own interests and having 
its own peculiar faculties, has at the same time its activi- 
ties subordinated to the good of the entire community. 

The Physiological Division of Labor. The fundamen- 
tal physiological properties, originally exhibited by all the 
cells, become ultimately distributed between the different 
modified cells which form the tissues of the fully developed 
Body much in the same way us different employments are 
distributed in « civilized state; for the difference between 
the fully developed human Body and the collection of 
amesboid cells fromm which it started is essentially the same 
ae that between a number of wandering savages and a civi- 
lized nation. In the former, apart from differences de- 
pendent on sex, each individual has no one special ocen- 

ion different from that of the rest, but has all his own 
needs to look after: he must collect his own food and 
prepare it for eating, make his own clothes if he wears 





28 THE HUMAN BODY. 


any, provide his own shelter, and defend himself from wild 
beasts or his fellow-men. In the civilized country, on the 
other hand, we find agriculturists to raise food and cooks 
to prepare it, tailors to make clothes, and policemen and 
soldiers to provide protection. And just as we find that 
when distribution of employments in it is more minute 
the more advanced a nation is in civilization, so is an ani- 
mal higher or lower in the scale according to the degree in 
which it exhibits a division of physiological duties between 
its different tissues, 

From the subdivision of labor in advanced communities 
several important consequences arise. In the first place, 
each man devoting himself to one kind of work mainly and 
relying upon others for the supply of his other needs, every 
sort of work gets better done. The man who is constantly 
making bouts becomes more expert than one whose atten- 
tion is constantly distracted by other duties, and he will not 
only make more boots in a given time, but better ones; and 
so with the performance of all other kinds of work. In 
the second place, a necessity arises for a new sort of indus- 
try, in order to convey the produce of one individual in 
excess of the needs of himself and his family to those at a 
distance who may want it, and to convey back in return 
the excess of their produce which he needs. The carriage 
of food from the country to cities, and of city produce 
to country districts, and the occupation of shopkeeping, 
are instances of these new kinds of labor which arise in 
civilized communities. In addition there is developed a 
need for arrangements by which the work of individuals 
shall be regulated in proportion to the wants of the 
whole community, such as is in part effected by the agency 
of large employers of labor who regulate the activities of 
a number of individuals for the production of various 
articles in the different quantities required at different 
times. 

Exactly similar phenomena result from the subdivision 
of labor in the human Body. By the distribution of em- 
ployments between its different tissnes, each one specially 
doing one work for the general community and relying on 





i 


CLASSIFICATION OF TISSUES. 29 


the others for their aid in turn, each necessary work is 


- better performed. And a need arises for a distributive 
mechanism by which the excess products, if any, of various 
tissues shall be carried to others which require them, and 
fora regulative mechanism by which the activities of the 
various tissues shall be rendered proportionate to the needs 
‘of the whole Body at different times and under different 
circumstances, Accordingly, as we may classify the in- 
habitants of the United States into lawyers, doctors, clergy- 
mon, merchants, farmers, and s0 on, we may 

Classify the Tissues, by selecting the most distinctive 

ies of each of those entering into the construc- 
tion of the adult Body und arranging them into pliysio- 
logical groups; those of each group being characterized by 
some one prominent employment. No such classification, 
however, can be more than approximately accurate, since 
the same tissue has often more than one well-marked 
physiological property. ‘The following grrangement, how- 
ever, is practically convenient. 

1. Undifferentiated Tissuos. These are composed of 
calls which have developed along no one special line, but 
retain very much the form and properties of the cells form- 
ing the very young Body before different tissues were re- 
cognizable in it, The lymph corpuscles and the colorless 
corpuscles of the blood belong to this class. 

2. Supporting Tissues. Including cartilage (gristle), 
bone, and connective tissue. Of the latter there are several 
subsidiary varieties, the two more important being white 
fibrous connective tissue, composed mainly of colorless in- 
extensible fibres, and yellow fibrous tissue, composed mainly 
of yellow clastic fibres. All the supporting tissues are used 
in the Body for mechanical purposes: the bones and carti- 
ages form the hard framework by which softer tissues are 
supported and protected; and the connective tissues unite 
the various bones and cartilages, form investing mem- 
branes around different organs, and in the form of fine 
networks penetrate their substance and support their con- 
atituent cells. ‘The functions of these tissues being for the 
most part to passively resist strain or pressure, none of 





30 THE HUMAN BODY. 


thom hus any very marked physiological property; they are 
not, for example, irritable or contractile, and their mass is 
chiefly made up of an intercellular substance which has 
been formed by the uctively living cells sparsely scattered 
through them, as for instance in cartilage, Fig. 42,*where 
the cells are seen imbedded in cavities in a matrix which 
they have formed around them; and which matrix by its 
firmness and elasticity forms the functionally important 
part of the tissue. 

8. Nutritive Tissues. This is a large group, the mem- 
bers of which fall into three main divisions, viz.: 

Assimilative tissues, concerned in receiving and prepar- 
ing food materials, and including—(a) Secretory tissues, 
composed of cells which make the digestive liquids poured 
into alimentary canal, and bringing about chemical or other 
changes in the food. (0) Receptive tissues, represented 
by cells which line parts of the alimentary canal and take 
up the digested food, 

Eliminative or exeretory tissues, represented by cells 
in the kidnoys, skin, and elsewhere, whose main business 
it is to got rid of the waste products of the various parts of 
the Body. 

Respiratory tissues. These are concerned in the gas- 

ges between the Body and the surrounding 
patituted by the cells lining the lungs 
and by the colored corpu of the blood. 

As regards the nutritive tissues it requires especially to be 
borne in mind that although such a classification as is here 
given is useful, as helping to show the method pursued in 
the domestic economy of the Body, it is only imperfect 
and largely artificial. Every cell of the Body is in itself 
assimilutive, respiratory, and excretory, and the tissues 
in this cluss are only those concerned in the first and 
last. interchanges of material between it and the external 
world. They provide or get rid of substances for the 
whole Body, leaving the feeding and breathing and exere- 
tion of its individual tissues to be ultimately looked after 
by themselves, just us even the mandarin described by Robin- 
son Crasoe who found his dignity promoted by haying 


*P. 101. 





STORAGE TISSUES, 31 


servants to put the food into his mouth, had finally to 
swallow and digest it for himself. Moreover, there is no 
logical distinction between a secretory and an excretory 
cell; each of them is characterized by the formation of cer- 
tain substances which are poured out on a free surface on 
the exterior or interior of the Body. Many secretory cells 
too haye no concern with the digestion of food, as for 
example those which form the tears and sweat. 

4. Storage Tissues. The Body does not live from: hund 
to mouth: it has always in health a supply of food materiale 
accumulated in it beyond its immediate needs. This lies 
in part in the individual cells themselves, just as in « pros- 
perous community nearly every one will have some little 
pocket-money. But apart from this reserve there are cer- 
tain cells, a sort of capitalists, which store up considerable 
quantities of material and constitute what we will call the 
storage tissues. These are especially represented by the 
liver-cells and fat-cells, which contain in health a reserve 
fund for the rest of the Body, Since both of these, to- 
gether with secretory and excretory cells, are the seats of 
great chemical activity, they are all often called metadolic 
tissues. 

5. Irritable Tissues. ‘The maintenance, or at any rate 
tho best procperity, of a nation is not fully secured when a 
division of Inbor has taken place i in food-supply and food- 
distribution employments. It is extremely desirable that 
means shall be provided by which it may receive informa- 
tion of external changes which may affect it as a whole, 
such as the policy of foreign countries ; or which shall en- 
able the inhabitants of one part to know the needs of an- 
other, and direct their activity accordingly. Foreign min- 
isters and consuls and newspaper correspondents are em- 
ployed to place it in communication with other states and 
keep it informed as to its interests; and we find also orga- 
nizations, such as the meteorological department, to warn 
distant parts of approaching storms or other climatic 
changes which may seriously affect the pursuits carried on 
in them. In the human Bod ave & comparable class 
of *telligence-gaining tissues lying in the sense organs, 





32 THE HUMAN BODY. 


whose business it is to ascertain and communicate to the 
whole, external changes which oceur around it. Since 
the usefulness of these tissues depends upon the readiness 
with which slight causes excite them to activity, we may 
call them the irritable Hiasues. 

6, Co-ordinating and Automatic Tissues. Such infor- 
mation as that collected by ministers in foreign parta or by 
meteorological observers, is usually sent direct to some cen- 
tral office from which it is redistributed; this mere redis- 
tribution is, however, in many cases but a small part of the 
work carried on in such offices. Let us suppose informa- 
tion to be obtained that an Indian chief is collecting his 
men for an attack on some point. The news is probably 
first transmitted to Washington, and it becomes the duty 
of the executive officers there to employ certain of the con- 
stituent units of the society in such definite work as is 
needed for its protection, Troops have to be sent to the 
place threatened; perhaps recruits enlisted; food and 
clothes, weapons and ammunition must be provided for 
the army; and so on. In other words, the work of the 
various classes composing the society has to be organized 
for the common good; the mere spreading the news 
of the danger would alone be of little avail. So in the 
Body: the information forwarded to certain centres from 
the irritable tissues is used in such a way as to arouse to 
orderly activity other tissues whose services are required; we 
find thus in these centres a group of co-ordinating tissues, 
represented by nerve-cells and possibly by certain other con- 
stituents of the nerve centres. Certain nerve-cells are also 
automatic in the physiological sense already pointed out. 
The highest manifestation of this latter faculty, shown 
objectively by muscular movements, is subjectively known 
us the *‘ will,” a state of consciousness; and other mental 
phenomena, as sensations and emotions, are also associated 
with the activity of nerve-cells lying in the brain, How it 
is that any one state of prial cell should give rise to a 
particular state of conse is a matter quite beyond 
our powers of conception; but not really more so than how 
it is that every portion of matter attracts every other por- 





MOTOR TISSUES. 


tion according to the law of inverse squares. In the 
living Body, us elsewhere in the universe, we can study 
phenomena and make out their relations of sequence or 
co-existence; but why one phenomenon is accompanied by 
another, why in fact any cause produces an effect, is a 
matter quite beyond our reach in every case; whether it be 
4 sensation accompanying a molecular change in a nerve- 
cell, or the fall of a stone to the ground in obedience to the 
law of gravitation. 

J. Motor Tissues. ‘These have the contractility of the 
original protoplasmic masses highly developed. The more 
important are ciliated cells and muscular tissue. The for- 
mer line certain surfaces of the body, and possess on their 
free surfaces fino threads which are in constant movement. 
One finds such cells, for example (Fig. 47*) lining the in- 
side of the windpipe, where their threads or cilia serve, by 
their motion, to sweep any fluid formed there towards the 
throat, whore it can be coughed up and got rid of. Mus- 
cular tissue occurs in two main varieties. One kind is 
found in the muacles attached to the bones, and which are 
used in the ordinary voluntary movements of the body. 
Tt is composed of fibres which present cross-stripes when 
viewed under the microscope (Fig. 538+), and is hence 
known as sfriped or striated muscular tissue. Tho other 
kind of muscular tissue is found in the walls of the 
alimentary canal and some other hollow orgins, and con- 
sists of elongated cells (Fig. 55{)which present no cross 
striation. It is known as plain or unstriated musoular 
tissue, 

Tho-cells enumerated under the heading of “ undiffer- 
eutiated tissues” might also be included among the motor 
tissues, since they are capable of changing their form, 

8. Tho Conductive Tissues, ‘These are represented by 
the nerve fibres, slender threads formed by modification 
and fusion of cells, and having the conductivity of the 
ammboid cells of the morula highly developed; that is to 
say, they readily transmit molecular disturbances. When 
its equilibrium is upset at one end, a norve-fibre will 
transmit to its other a molecular movement known as a 


*P, 115. +P. 128, ¢P. 1k 








84 THE HUMAN BODY. 


“nervous impulse,” and so can excite in turn parts distant 
from the original exciting force. Nerve-fibres place, on 
the one hand, the irritable tissues in connection with the 
automatic, co-ordinating, and sensory; and on the other 
put the three latter in communication with the muscular, 
secretory, and other tissues. 

9. Protective Tissues. These consist of certain cells 
lining cavities inside the body and called epithelial cells, 
and cells covering the whole exterior of the Body and 
forming epidermis, hairs, and uails. The enamel which 
covers the teeth belongs also to this group. 

The class of protective tissues is, however, even more 
artificial than that of the nutritive tissues, and cannot be 
defined by positive characters. Many epithelial cells are 
secretory, excretory, or receptive; and ciliated cells haye 
already been included among the motor tissues, although 
from the fact that the movements of their cilia go on 
in separated cells and independently of recognizable oxter= 
nal stimuli, they might well have been put among the au- 
tomatic. The protective tissues may be best defined as 
including cells which line free surfaces, and whose func- 
tions are mainly mechanical or physical, 

10. The Reproductive Tissues, These are concerned 
in the production of new individuals, and in the haman 
Body are of two kinds, located in different sexes. The 
conjunction of the products of each sex is necessary for the 
origination of offspring, since the ovum, or female pro- 
duet which directly develops into the new human being, 
lies dormant until it has been fertilized or acted upon by 
the product of the male, 

The Combination of Tissues to Form Organs, ‘I'he va- 
rious tissues above enumerated forming the building mate- 
rials of the Body, anatomy is primarily concerned with 
their structure, and physiology with their properties. If 
this, however, were tho whole matter, the problems 
of anatomy and physiology would be much simpler 
than they actually are. The knowledge about the living 
Body obtained by studying only the forms and functions 





ORGANS. BH 


of the individual tissues would be comparable to that at- 
tained about u great factory by studying separately the 
boilers, pistons, levers, wheels, ete., found in it, and leay- 
ing out of account altogether the way in which these are 
combined to form various machines; for in the Body the 
varios tissues are for the most part associated to form 
organs, each organ answering to a complex machine like a 
steam-engine with its numerous constituent parts. And 
just as in different machines a cogged wheel may perform 
very different duties, dependent upon the way in which it 
is connected with other parts, so in the Body any one tis- 
sue, although its essential properties are everywhere the 
same, may by its activity snbserve very various uses accord 
ing to the manner in which it is combined with others. 
For example: A nerye-fibre uniting the eye with one part 
of the brain will, by means of its conductivity, when its 
end in the eye is excited by the irritable tissue attached to 
it on which light acta, cause changes in the sensory nerve- 
cells connected with its other end and so arouse a sight 
sensation; but an exactly similar nerve-fibre rnnning from 
the brain to the muscles will, also by virtne of its conduc- 
tivity, when its ending in. the brain is excited by a change 
in a nerve-cell connected with it, stir up the muscle to con- 
tract under the control of the will. ‘The different results 
depend on the different parts connected with the ends of 
the nerve-fibres in each case, and not on any difference in 
the properties of the nerve-fibres themselves. 

Tt becomes necessary then to study the arrangement and 
tuses of the tissues a3 combined to form various organs, and 
this ts frequently far more difficult than to make out the 
structure and properties of the individual tissnes, An or- 
dinary muscle, such ag one sees in the lean of meat, isa 
yery complex organ, containing not only contractile mus- 
cular tissue, but supporting and uniting connective tissue 
and conductive nerve-fibres, and in addition a complex 
commissariat arrangement, composed i turn of several 
tissues, concerned in the food. ply and waste removal of 
the whole muscle. The anatomical study of a muscle has 





86 THE HUMAN BODY. 


to take into account the arrangement of all these parts 
within it, and also its connections with other organs of the 
Body. The physiology of any muscle must take into ac- 
count the actions of all these parts working together and 
not merely the functions of the muscular fibres themselves, 
and has also to make out under what conditions the muscle 
is excited to activity by changes in other organs, and what 
changes in these it brings about when it works. 
Physiological Mechanisms. Even the study of organs 
added to that of the separate tissues does not exhaust the 
whole matter. In a factory we frequently find machines 
arranged so that two or more shall work together for the 
performance of some one work: a steam-engine and a loom 
may, for example, be connected and used together to weave 
carpets, Similarly in the Body several organs are often 
arranged to work together so as to attain some one end by 
their united actions. Such combinations are known as 
physiological apparatuses. The circulatory apparatus, for 
example, consists of various organs (each in turn composed 
of several tissues) known as heurt, arteries, capillaries, and 
veins. The Aeart forms a force-pump by which the blood 
is kept flowing through the whole mechanism, and the 
rest, known together as the diood-vessels, distribute the 
blood to the various organs and regulate the supply accord- 
ing to their needs. Again, in the visual apparatus we find 
the co-operation of (a) a set of optical instruments which 
bring the light proceeding from external objects to a focus 
upon () the refina, which contains highly irritable parts; 
these, changed by the light, stimulate (c) the optic nerve, 
which is conductive and transmits a disturbance which 
arouses finally (@) sensory parts in the brain. In the pro- 
duction of ordinary sight sensations all these parts are con- 
cerned and work together as a visual apparatus. So, too, 
we find a respiratory apparatus, consisting primarily of two 
hollow organs, the Zungs, which lie in the chest and com- 
municate by the windpipe with the back of the throat, 
from which air enters thom. But to complete the respi- 
ratory apparatus are many other organs, bones, muscles, 
nerves, and nerve-centres, which work together to renew 





ANATOMICAL SYSTEMS, 87 


the air in the lungs from time to time; and the act of 
breathing is the final result of the activity of the whole 


apparatas. 

Many similar instances, as the alimentary apparatus, the 
auditory apparatus, and so on, will readily be thought of. 
‘The study of the working of such complicated mechanisms 
forms a yery important part of physiology. 

Anatomical Systems. From the anatomical side the 
whole collection of bodily organs agreeing in stracture 
with one another is often spoken of as a system; all the 
muscles, for example, are grouped together as the muscular 
system, and all the bones as the osseous system, and 80 on, 
withont any reference to the different uses of different 
muscles or bones. ‘The term system is, however, often used 
as equivalent to “apparatus:” one reads indifferently of the 
“circulatory system” or the ‘circulatory apparatus.” Tt 
is better, however, to reserve the term system for a collec- 
tion of organs clussed together on account of similarity of 
structure; and ‘‘apparatus” for a collection of organs con- 
sidered together on account of their co-operation to execute 
one function. The former term will then have an anatomi- 
cal, the latter a physiological, significance. 

The Body asa Working Whole. Finally it must all 
through be borne in mind that not even the most complex 

can be considered altogether alone as 

living part. All are united to make one 
living Body, in which there is throughout a mutual inter- 
dependence, so that the whole forms one human being, in 
whom the circulatory, respiratory, digestive, sensory, and 
other apparatuses are constantly influencing one another, 
esol modifying the activities of ‘the rest. ‘This interaction 
is mainly brought about through the conductive and co- 
ordinating tissues of the 
parts of the Body in communi q i 
this another bond of union t blood, which 
by the circulatory apparatu f jasne to tissue 
and organ to organ, and so, i 
oné region to distant parts, enables cach organ to influence 
all the rest for good or ill. 





38 THE HUMAN BODY. 


Besides the blood another liquid, called lymph, exists in 
the Body, It is contained in vessels distinct from those 
which carry the blood, but emptying into the blood-vessels 
at certain points. 'This liquid being also in constant move- 
ment forms another agency by which products are carried 
from part to part, and the welfare or ill-fare of one member 
enabled to influence all. 





CHAPTER IV, 
THE INTERNAL MEDIUM. 


‘The External Medium. During the whole of life inter- 
changes of material go on between every living being and 
the external world; by these exchanges material particles 
that one time constitute parts of inanimate objects come 
at another to form part of a living being; and later on 
these same atoms, after having been a part of a living cell, 
are passed out from the Body in the form of lifeless com- 
pounds, As the foods and wastes of various living things 
differ more or less, so are more or less different environ- 
ments suited for their existence; and there is accordingly 
a relationship between the plants and animals living in 
auy one place and the conditions of air, earth, and water 
prevailing there. Even such simple unicellular animals as 
the ammba live only in water or mud containing in solu- 
tion certain gases and, in suspension, solid food particle: 
and they soon die if the water be changed either by essen- 
tially altering its gases or by taking out of it the solid food. 
So in yeast we find a unicellular plant which thrives and 
multiplies only in liquids of certain composition, and which 
in the absence of organic compounds of carbon in solution 
will not grow at all. Each of these simple living things, 
which corresponds to one only of the innumerable cells 
composing the full-gr 
the manifestati 


in a lignid containing only the 
solid organic py lk 3 and 
the amoba would die in such solutions as those in which 
yeast thrives best. 





40 THE HUMAN BODY. 


Tho Internal Medium. ‘The same close relationship 
between the living being and its environment, and the 
same cyclical interchange between the two which we find 
in the amaba and the yeast-cell, occur also in even the 
most complex living beings. When, however, an animal 
comes to be composed of many cells, some of which are 
placed far away from the surface of its body and so from 
immediate contact with the environment, there arises a new 
necd—a necessity for an internal medium or plasma which 
shall play the same part toward the individual cells as the 
surrounding air, water, and food to the whole animal. This 
internal medium kept in movement, and receiving at some 
regions of the bodily surfaces materials from the exterior, 
while losing other substances to the exterior at other sur- 
faces, thus forms a sort of middleman between the in- 
dividual tissues and the surrounding world, and stands in 
the same relationship to cach of the cells of the Body ag 
the water in which an amocha lives does to that animal or 
beer-wort does to a yeast-vell. We find accordingly the 
human Body pervaded by a liquid plasma, containing gases 
and food material in solution, and the presence of which is 
necessary for the maintenance of the life of the tissues. 
Any great change in this medinm will affect injuriously 
few or many of the groups of cells inthe Body, or may even 
eause their death; just as altering the media in which 
they live will kill an amovba or a yeast-cell, 

The Blood, In the human Body the internal medium is 
primarily furnished by the blood, which, as every one 
knows, is a red liquid, very widely distributed over the 
frame, since it flows from any part when the skin is cut 
through. There are in fact very few portions of the Body 
into which the blood is not carried. One of the exceptions 
is the epidermis, or outer layer of the skin: if a cut be 
made through it only, leaving the deeper skin-layers in- 
tact, no blood will flow from the wound. Haire and mails 
also contain no blood. In the interior of the Body the 
epithelial cells lining free surfaces, such as the inside of 
the alimentary canal, contain no blood, nor do the hard 
parts of the teeth, the cartilages, and the refracting media 





THE INTERNAL MEDIUM, a 


of the eye (seo Chap. XXXI.), but these interior parts are 
moistened with liquid of some kind, and unlike the epi- 
dermis are protected from rapid evaporation. All these 
bloodless parts together form a group of non-vasenlar tis- 
sues; they alone excepted, wounding any part of the Body 
will be followed by bleeding. 

In many of the lower animals there is no need that the 
liquid representing their blood should be renewed very 
rapidly in different parts. Their cells live slowly, and so 
require but little food and produce but little waste. In a 
sea anemone, for example, there is no special arrangement 
to keep the blood moving; it is just pushed about from 
part to part by the general movements of the body of the 
animal. But in higher animals, especially those with an 
elevated temperature, such an arrangement, or rather ab- 
sence of arrangement, as this would not suffice. In them 
the constituent cells live very fast, making much waste and 
using much food, and so alter the blood in their neigh- 
borhood very rapidly. Besides, we have seen that in com- 
plex unimals certain cells are set apart to” get food for the 
whole organism, and certain others to finally remove its 
wastes, and there must be a sure and rapid interchange of 
material between the feeding and excreting tissues and all 
the others, This can only be brought about by a rapid 
movement of the blood in a definite course, and this is ae- 
complished by shutting it up in a closod set of tubes, and 
placing somewhere a pump, which constantly takes in 
blood from one end of the system of tubes and forces it 
ont again into the other. Sent by this pump, the heart, 
through all parts of the Body and back to the heart 
again, the blood gets food from the receptive cells, takes it 
to the working cells, carries off the waste of these latter to 
the excreting cells ; and so the round goes on. 

The Lymph, The blood, however, lies everywhere in 
closed tubes formed by the vascular system, and does not 
come into direct contact with any cells of the Body except 
those which float in it and those which line the interior 
of the blood-vessels. At one part of its course, however, 
the yessels through which it passes have extremely thin 





42 THE HUMAN BODY. 


coats, and through the walls of these capillaries liquid 
transudes from the blood and bathes the various tissues. 
‘The transuded liquid is the Jymph, and it is this which 
forms the immediate nutrient plasma of the tissues except 
the few which the blood moistens directly. 

Dialysis. When two liquids containing different mat- 
ters in solution are separated from one another by a moist 
animal membrane, an interchange of material will take 

place under certain conditions. If A be a 
vessel (Fig. 9) completely divided vertically 
by sach » membrane, and a solution of com- 
mon salt in water be placed on the side 4. 
and a solution of sugar in water on the side 
c, it will be found after a time that some 
salt has got into ¢ and some sugar into é, al- 
though there are no visible pores in the parti- 
tion, Such an interchange is said to be due 
to dialysis or osmosis, and if the process were 
allowed to go on for some hours the same 
proportions of salt and sugar would be found in the solu- 
tions on each side of the dividing membrane. 

The Renewal of the Lymph. Osmotic processes play a 
great part in the nutritive processes of the Body. The 
lymph present in any organ gives up things to the cells there 
and gets things from them; and so, although it may have 
originally been tolerably like the liquid part of the blood, it 
e0on acquires a different chemical composition. Diffusion 
or dialysis then commences between the lymph outside and 
the blood inside the capillaries, and the latter gives up to 
the lymph new materials in place of those which it has loet 
and takes from it the waste. products it has received from 
the tissues. When this blood thus altered by exchanges 
with the lymph gets again to the neighborhood of the re- 
ceptive cells, having lost some food materiuls it is poorer 
in these than the richly supplied lymph around those cells, 
and takes up a supply by dialysis fi it. When it reaches 
the excretory organs it has p ked up a quantity 
of waste matters and loses these by dialysis to the lymph 
there present, which is specially poor in such matters, 





LYMPHATIOS. 43 


since the exeretory cells constantly deprive it of them. In 
consequence of the different wants and wastes of various 
cells, and of the same cells at different times, the lymph 
must vary considerably in composition in various organs of 
the Body, and the blood flowing through them will get or 
lose different things in different places. But renewing 
during its cirenit in one what it loses in another, its ayer 
age composition is kept pretty constant, and, through in- 
terchange with it, the average composition of the lymph 
also. 

The Lymphatic Vessels. The blood, on the whole, 
loses more liquid to the lymph throngh the capillary walls 
than it receives back the same way. This depends mainly 
on the fact that the pressure on the blood inside the ves- 
sels is greater than that on the lymph outside, and so a 
certain amount of filtration of liquid from within out 
oceurs through the vuscular wall in addition to the dialysis 
proper. ‘The excess is collected from the various organs of 
the Body into a set of lymphatic vessels which carry it 
directly back into some of the larger blood-vessels near 
whore these empty into the heart; and by this flow of lymph, 
under pressure from behind, it is renewed in various or- 
gans, fresh liquid filtering through the capillaries to take 
its place as fast us the old is carried off. 

The Lacteals. In the walls of the alimentary canal cer- 
tain food materials after passing throngh the receptive cells 
into the lymph are not transferred locally, like the rest, by 
dialysis into the blood, but are carrriod off bodily in the 
lymph-vessels and poured into the veins of a distant part 
of the Body. The lymphatic vessels concerned in this 
work, being frequently fillod with a w iquid during di- 
gestion, are called the m 2 

Summary. To sum up: the blood and lymph form the 
internal medium in which the tissues of the Bo ; the 
lymph is primarily derived from the blood and forma the 
immediate plasma for the majority of the living cells 
of the Body; and the exce: it is finally returned to the 
blood. The lymph mo at slowly, but is constantly 
renovated by the blood, which is kept in rapid movement, 





44 THE HUMAN BODY. 


and which, besides containing a store of new food matters 
for the lymph, carries off the wastes which the various cells 
have poured into the latter, and thus is also a sort of sewage 
stream into which the wastes of the whole Body are pri- 
marily collected. 

Microscopic Characters of Blood. If a finger be 
pricked, and the drop of blood flowing out be received on 
a glass slide, covered, protected from evaporation, and ex- 
amined with a microscope magnifying about 400 diameters, 
it will be seen to consist of innumerable solid bodies float- 
ing in aliquid. The solid bodies are the blood corpuscles, 
and the liquid is the dlood plasma or lignor sanguinis. 

The corpuscles are not all alike. While currents still 
exist in the freshly spread drop of blood, the great majority 
of them are readily carried to and fro; but a certain num- 
ber more commonly stick to the glass and remain in one 
place. The former are the red, the latter the pale or color- 
less blood corpuscles. 

Red Corpuscles. orm and Size. The red corpuscles as 
they float about frequently seem to vary in form, but by a 
little attention it can be made out that this appearance is 
due to their turning round as they float, and so presenting 
different aspects to view; just as a silver dollar presents a 
different outline according as it is looked at from the front 
or edgewise or in three-quarter profile. 

Sometimes the corpuscle (Fig. 10, B) appears circular; 
then it is seen in full face; sometimes linear (@), and 
slightly narrowed in the middle; sometimes oval, as the 
dollar when half-way between a full and a side view. 
‘Theso appearances show that each red corpuscle is a ciren- 
lar disk, slightly hollowed in the middle (or biconcave) and 
about four times as wide as it is thick. The average trans- 
verse diameter is 0.008 millimeter (qy¥y9 inch).—Oolor. 
Seen singly each red corpusele is of a pale yellow color; it 
is only when collected in masses that they appear red. 
The blood owes its red color to the great numbers of these 
bodies in its if it be spread out in a yery thin layer it, too, 
is yellow. The layer must, however, be very thin or the 
drop will still look red on account of the immense number 





BLOOD. 45 


of these corpuscles present; in a cubic millimeter (, inch) 
of blood there are about five millions of them.—Structure. 
Seen from the front the central part of each red corpuscle 
iu @ certain focus of the microscope appears dimmer or 
darker than the rest (Fig. 10, 2), except a narrow band 
near the outer rim. If the Jens of the microscope be raised, 
however, this previously dimmer central part becomes 
brighter, and the previously brighter part obscure (Z). 





This difference in appearance docs not indicate the presence 
of a central part or nucleus different from the rest, but is 
‘an optical phenomenon due to the shape of the corpuscle, 
in consequence of which it acts like a little biconcave lens 
(see Physics). Rays of light passing through near the 
centre of the corpuscle are refracted differently from those 
passing through elsewhere; and when the microscope is 
20 focused that the latter reach the eye, the former do nut, 


46 TRE HUMAN BODY, 


and vice versa; thus when the central parts look bright, 
those around them look obscure, and the contrary. 

There is no satisfactory evidence that these corpuscles 
have any enveloping sac or cell-wall. All the methods 
used to bring one into view under the microscope are such 
as would coagulate the outer layers of the substance com- 
posing the corpusele and so make an artificial envelope. 
So far as optical analysis goes, then, each corpuscle is ho- 
mogeneous throughout. By other means we can, however, 
show that at least two materials enter into the stracture 
of each red corpuscle. If the blood be diluted with several 
times its own bulk of water and be then examined with the 
microscope, it will be found that the red corpuscles are col- 
orless and the plasma colored. The dilution has caused 
the coloring matter to pass out of the corpuscles and dis- 
solve in the liquid. This coloring constituent of the cor- 
puscle is hemoglobin, and the colorless residue which it 
leaves behind and which swells up into a sphere in the di- 
Inted plasma is the stroma, In tho living corpuscle the 
two are intimately mingled throughout it, and so long as 
this is the case the blood is opaque; but when the coloring 
mattor dissolves in the plasma, then the blood becomes 
transparent, or, as it is called, Jaky. The difference may 
be very well seen by comparing « thin layer of fresh blood 
diluted with ten times its volume of ten-per-cent salt #0- 
lution with a similar layer of blood diluted with ten vol- 
umes of water. The watery mixture is a dark transparent 
red; the other, in which the coloring matter still lies in 
the corpuscles, is a brighter opaque red.—Consistency. 
Each red corpuscle is a soft jelly-like mass which can be 
readily crushed out of shape. Unless the pressure be euch 
as to rupture it, the corpuscle immediately reassumes its 
proper form when the exte force is removed. The cor- 
puscles are, then, highly elastic; they frequently can be seen 
much dragged ont of shape inside the vessels when the 
circulation of the blood is watched in a living animul 
(Chap. XV.), but immediately springing back to their nor- 
mal form when they get » chance. 

Blood-Crystals. Hemoglobin is, as above shown, readily 





BLOOD-ORYSTALS. ay 


soluble in water. In this it soon decomposes if kept in a 
‘warm room, breaking up into a proteid substance called 


globulin and a red-colored body, hematin. By keeping 
the hwmoglobin solution very cold, however, this decompo- 
sition can be greatly retarded, and at the same time the 
solubility of the hemoglobin in the water much diminished. 
Tu dilute alcohol hwmoglobin is still less soluble, and so if 
its ice-cold watery solution have one fourth of its yolame 
‘of cold alcohol added to it and the mixture be put in a re- 
frigerator for twenty-four hours, a part of the hmmoglobin 
will often crystallize out and sink to the bottom of the 
yossel, where it can be collected for examination. The 
hemoglobin of the rat is 

less soluble than that of 

man, and therefore crys- 

tallizes out especially 

easily; but these hemo- 

globin crystals, or, as 

they are often called, 

blood-crystals, can be 

obtained from haman 

blood. In 100 parts of 

dry butian. red’ blood. ope" “c7mAs oF Bamogibta 
corpuscles there are 90 of hemoglobin. The hemoglobin 
is the essential constituent of the red blood corpuscles, 
enabling them to pick up large quantities of oxygen in 
the lungs and carry it to all parts of the Body, (See Res- 
piration.) 

Hemoglobin contains a considerable quantity of iron, 
much more than any other proximate constituent of the 
Body. 

‘The Colorless Blood Corpuscles (Fig. 10, F, H, @). 
The rolorless, pale, or whi! rpuscles of the blood are far 
less numerous than the red; in health there is on the ave- 
rage about one white to three hundred red, but the pro- 
portion may vary considerably. Each is 
and consists of a soft mass of protoplasin enve 
definito cell-wall, but containing a nucleus. The granules 
in the protoplasm commonly hide the nucleus in a fresh 








48 THE HUMAN BODY, 


corpuscle, but dilute acetic acid dissolves most of them 
and brings the nucleus into view. ‘These pale corpuscles 
belong to the group of undifferentiated tissues and differ in 
no important recognizable character from the cells which 
make up the whole yery young human Body, nor indeed 
from such an unicellular animal as an Amaba. Like the 
latter, they have the power of slowly changing their form 
spontaneously, and so have not the definiteness of outline 
which belongs to the red corpuscles. At one moment 

(Fig. 12) a pale corpusele will be seen 

Qy:: a spheroidal mass; afew seconds 

Q pi: processes will be seen radiating 


from this, and soon after these pro- 
cesses may be retracted and others 
Gm out; and so the corpuscle goes 
G* changing its shape. These slow 
ameboid movements are greatly pro- 
cote tt arent moted by keeping the specimen of 
Seale Pos eta tow blood at the temperature of the Body 
Stange of tran forma dive to 8 whileunder examination. By thrust- 
ing out a process on one side, then 
drawing the rest of its body up to it, and then sending out 
a process again on the same side, the corpuacle can slowly 
change its place and creep across the field of the micro- 
scope. Inside the blood-vessels these corpuscles execute 
quite similar movements; and they sometimes bore right 
through the capillary walls and, getting ont into the lymph 
spaces, creep about among the other tissues. This emigra- 
tion is especially frequent in inflamed parts, and the pus 
or “ matter” which collects in abscesses is largely made up 
of white blood corpuscles which have in this way got out of 
the blood-vessels, The size of the white corpuscles is not 
so constant as that of the red; on the whole, however, they 
are larger, their average diameter being about 0.0127 milli- 
meter (g¢rx inch). The general properties of those cor- 
puscles hive already been described in Chap. II. 
Blood of Other Animals. In all animals with blood the 
pale corpuscles are pretty much alike, but the red corpus- 
cles, which with rare exceptions are found only in Verte- 





LYMPH. 49 


brates, vary considerably. Inall the class of the mammalia 
they are circular biconcave disks with the exception of the 
eamel tribe, in which they are oval. ‘They vary in diam- 
eter from .002 mm. (musk deer) to 011 mm, (elephant). In 
the dog they ure nearly the same size as those of man. In 
no mammals do the fally developed red corpuscles possess 
a nucleus. In all other vertebrate classes the red corpua- 
eles possess acentral nucleus, and are oval slightly biconvex 
disks except in a few fishes in which they are circular. 
‘They are largest of all in the amphibia. Those of the frog 
are 0.03 mm. ( y's inch ) long and .007 mm. broad. 

Histology of Lymph. Purelymph is a colorless watery- 
looking liquid; examined with a microscope it is seen to 
contain numerons pale corpuscles exactly like those of the 
blood, and no doubt largely consisting of pale blood cor- 
puscles which have emigrated. Tt contains none of the 
red corpuscles. The lymph flowing from the intestines 
durmg digestion is, as already mentioned, not colorless 
but white and milky. It is known as chyle and will be 
considered with the process of digestion. During fasting 
the lymph from the intestines is colorless like that from 
other parts of the Body, 





CHAPTER V. 
THE CLOTTING OF BLOOD. 


The Coagulation of tho Blood, When blood is first 
drawn from the living Body it is perfectly liquid, flowing 
in avy direction as readily as water. ‘This condition is, 
however, only temporary ; in a few minutes the blood be- 
comes viscid and sticky, and the viscidity becomes more 
and more marked until, after the lapse of five or six min- 
utes, the whole mass ects into a jelly which adheres to 
the veesel containing it so that this may be inverted without 
any blood whatever being spilled. This stage is known 
as that of gelatinization and is also not permanent. In 
4 few minutes the top of the jelly-like mass will be seen 
to be hollowed or ‘‘cupped” and in the concavity will be 
seen a small quantity of nearly colorless liquid, the blood 
serum. The jelly next shrinks so as to pull itself loose 
from the sides and bottom of the vessel containing it, and 
ag it shrinks, squeezes out more and more serum. Ulti- 
mately we get a solid elot, colored red, and smaller in size 
than the yessel in which the blood coagulated but retain- 
ing its form, floating in a quantity of pale yellow serwm. 
If, however, the blood be not allowed to coagulate in per- 
fect rest, a certain number of red corpuscles will be rubbed 
out of the clot into the serum and the latter will be more 
or less reddish. The longer the clot is kept the more serum 
will be obtained: if the first quantity exuded be decanted 
off and the clot put aside and protected from evaporation, 
it will in a short time be found to have shrank to a smaller 
size and to have pressed out more serum; and this goes on 
us long as it is kept, until putrefactive changes commence, 





CAUSES OF COAGULATION. o1 


Cause of Coagulation. If a drop of fresh-drawn blood 
be spread out and watched with a microscope magnifying 
600 or 700 diameters, it will be scen that the coagulation is 
due to the separation of very fine solid threads which ran 
in every direction through the plasma and form a close 
network entangling all the corpuscles. These threads are 
composed of a proteid substance known as fibrin. When 
they first form, the whole drop is much likea sponge soaked 
fall of water (represented by the serum) and having solid 
bodies (the corpuscles) in its cavities. After the fibrin 
threads have been formed they tend to shorten; hence 
when blood clots in mass in a vessel, the fibrinous network 
tends to shrink in every direction just as a network 
formed of stretched imdia-rubber bands would, and this 
shrinkage is greater the longer the clotted blood is kept. 
At first the threads stick too firmly to the bottom and sides 
of the vessel to be pulled away, and thus the first sign of 
the contraction of the fibrin is seen in the cupping of the 
surface of the gelutinized blood where the threads have no 
solid attachment, and there the contracting mass presses 
ont from ita meshes the first drops of serum. Finally the 
contraction of the fibrin overcomes its adhesion to the vessel 
and the clot pulls itself loose on all sides, pressing out 
more and more serum, in which it ultimately floats. The 
grat majority of the red corpuscles are held back in the 
meshes of the fibrin, but a good many pale corpuscles, by 
their ameboid movements, work their way out and get 
into the seram. 

Whipped Blood, The essential point in coagulation 
being the formation of fibrin in the plasma, and blood only 
forming 4 certain amount of fibrin, if this be removed as fast 
as it forms the remaining blood will not clot. ‘The fibrin 
may be separated by what is known as “whipping” the 
blood. For this purpose fresh-drawn blood is stirred up yig- 
oroualy with a bunch of twigs, and the sticky fibrin threads 
as they form adhere to these. If the twigs be withdrawn 
after a few minntes a quantity of stringy material will be 
found attached to them. This is at first colored red by 
adhering blood corpuscles: but by washing in water thesa 








52 THE HUMAN BODY. 


may be removed, and the pure fibrin thus obtained is per- 
fectly white and in the form of highly elastic threads. It 
is insoluble in water and in dilute acids, but swells up to a 
transparent jelly in the latter, The “whipped” or “defi- 
brinated blood” from which the fibrin has been in this way 
removed, looks just like ordinary blood, but has lost its 
power of cougulating spontaneously. 

‘The Buffy Coat. That the red corpuscles are not an 
essential part of the clot, but are merely mechanically 
canght up in it, seems clear from the microscopic ob- 
servation of the process of coagulation; and from the fact 
that perfectly formed fibrin can be obtained free from cor- 
puseles by whipping the blood and washing the threads 
which adhere to the twigs. Under certain conditions, 
moreover, one gets a naturally formed clot containing no 
red corpuscles in one part of it. The corpuscles of human 
blood are a little heavier, bulk for bulk, than the plasma 
in which they float; hence, when the blood is drawn and 
left at rest they sink slowly in it; and if for any reason the 
clotting takes place more slowly or the corpuscles sink 
more rapidly than usual, a colorless top stratum of plasma, 
with no red corpuscles in it, will be left before gelatiniza- 
tion ocenrs and stops the farther sinking of the corpuscles. 
The uppermost part of the clot formed under these cir- 
eumstances is colorless or pale yellow, and is known as the 
buffy coat; it is especially apt to be formed in the blood 
drawn from febrile patients, and was therefore a point to 
which p! ns paid much attention in the olden times 
when bloodletting was thought a panacea for all ills, In 
horse's blood the difference between the specific gravity of 
the puerta a that tor than in hu- 


















USES OF COAGULATION. 


which forms a bright red compound with the coloring mat- 
ter ofthe red corpuscles. If the clot be turned upside down 
‘and left for a short time, the previously dark bottom layer, 
now exposed to the air, will become bright; and the previ- 
ously bright top layer, now immersed in the serum, will 
become dark. 

‘Uses of Coagulation. The clotting of the blood is so 
important a process that its cause has been frequently in- 

; but as yet it is not perfectly understood. ‘The 
li cirenlating blood in the healthy blood-vessels does 
not clot; it contains no solid fibrin, but this forms in it, 
sooner or later, when the blood gets by any means out of the 
vessels or if the lining of these isinjured. In this way the 
mouths of the small vessels opened in « cut are clogged up, 
and the bleeding, which would otherwise go on indefinitely, 
is stopped. So, too, when a surgeon ties up an artery be- 
fore dividing it, and the tight ligature crushes or tears its 
delicate inner surface, the blood clots where this is injured, 
and from there a coagnlum is formed reaching up to the 
next highest branch of the vessel. This becomes more and 
more solid, and by the time the ligature is removed has 
formed a,firm plug in the cut end of the artery, which 
greatly diminishes the risk of bleeding, 

The Fibrin Factors. As regards the formation of 
fibrin the following points seem to be mado out with toler- 
able certainty. Fresh-drawn blood contains or develops 
two substances, fidrinoplastin and fibrinogen, which by 
their interaction form fibrin, under the influence of a third 
body called the jidrin ferment; moreover, fibrin is only 
formed if a certain proportion of neutral mineral salts, 
aah a ore found dissolved in the blood plasma, is present. 

serum does not clot of itself at ordinary tempera- 
tures: it contaims fibrinoplastin and fibrin ferment and 
the requisite quantity of sults, but not the fibrinogen; that 
which originally existed in the plasma having apparently 
heen used up with the proper proportion of fibrinoplastin 
‘to form fibrin, leaving over an excess of fibrinoplustin in 
solution in the serum. 

“9n the other hand, the liquids found in the cavities of 





y v7 
lie” 


a THE HUMAN BODY, 


the Body which are lined by serous membranes, commonly 
contain fibrinogen and the salts but no fibrinoplastin, and 
therefore they do not coagulate spontaneously. But if a 
little blood serum be added to one of these liquids, cougula- 
tion takes place. 

Artificial Clot. If serum be slightly diluted with water 
and kept ice-cold while a stream of carbon dioxide gus is 
passed through it for some hours, a white precipitate is 
thrown down which contains fibrifoplastin and the fibrin 
ferment. This precipitate after washing may be dissolved 
in cold water containing the merest trace of caustic potash. 
If the liquid moistening a serous cavity be treated in a 
similar way a precipitate is formed, containing fibrinogen 
instead of the fibrinoplastin, and but little of the ferment. 
If this precipitate be washed and dissolved wnd,the solution 
be added to the solution of the blood-serum” precipitate, 
no clot is formed; but if about one per cent of sodic car- 
bonate or other neutral salt be added to the mixture, then 
it clots. This shows the necessity of the salts, which is 
perhaps better proved in another way. If serum be put in 
a dialyzer (sce Physics) with distilled water on the other 
side of the membrane, all the salts will gradually pass out 
from the serum into the water: as the last portions of 
them pass out, the fibrinop! n and ferment, which are 
* colloids” (that is, bodies which will not dialyze), are pre- 
cipitated; they may be redissolved by the addition of a 
trace of caustic potash. Similarly the salts may be ro- 
moyed from the liquid obtained from a serous cavity, and 
the precipitated fibrinogen redissolved. If those solutions 
be now mixed no clot is formed; but if the salts which have 
been dialyzed out, or an equivalent portion of other neu- 
tral salts, be added to the mixture, it will clot. 

The Fibrin Ferment. ‘he activity of the ferment ir 
proved as follows: If scrum be diluted with a large bulk of 

~ water_and then carbon dioxide gas be passed through it, 
fibrinoplastin will be precipitated, with little or none of 
the ferment. If this fil in be dissolved and added 
to the liquid from a serous cavity it will not cause it to 
clot, or only very slowly, according as no fibrin ferment or 





FIBRIN FERMENT. - 55 


but a little is present. But if some of the ferment be 
added, then the mixture coagulates rapidly. The ferment 
may be obtained by adding a large quantity of strong al- 
cohol to some fresh blood serum. ‘The alcohol precipi- 
tates albumen, fibrinoplastin, and the ferment, The pre- 
cipitate is let stay under aleohol for some months, during 
which time the albumen and fibrinoplastin are altered so 
us to become insoluble in water, The aleohol is then de- 
canted off and the residue treated with water which dis- 
solves the ferment. This solution added to the above 
mixture containing fibrinoplastin, fibrinogen, and salts, 
will make it clot. 

Of these four bodies which play a part in the coagula- 
tion of the blood, the fibrinoplastin and fibrinogen. pri- 
marily determine the quantity of fibrin formed. The fer- 
ment seems to act on them in some way so as to make them 
interact, but it does not enter into the fibrin; it is not used 
up in the process, and the quantity of fibrin formed is thus 
independent of the quantity of the ferment present; but 
the more of it there is, the more quickly does the cougula- 
tion occur. The part the salts play is obscure: probably 
part of them are necessary constituents of the fibrin, since 
it leaves a large proportion of ash when burnt. But they 
seem to act in some other way when present in certain 
proportions, since too large a percentage of them stops 
eongulation as completely as their total absence, If fresh 
blood be mixed with an equal bulk of a saturated solution 
of magnesium sulphate (Epsom salts) or of common salt, 
it will not clot; but if this mixture be largely diluted with 
water, then clotting will take place. 

Exciting Causos of Coagulation, The above facts show 
clearly enough that the coagulation of the blood is a 
physico-chemical process, but still leave unexplained why 
it does not occur in circulating blood inside healthy blood- 
vessels. It is, in fact, much easier to point out what are 
not the proximate reasons of the coagulation of drawn 
blood than what are. 

Blood when removed from the Body and received in a 
‘vessel comes to rest, cools, and is exposed to the air, from 





56 THE HUMAN BODY, 


which it may receive or to which it may give off gaseous 
bodies. But it is eusy to prove that none of these three 
things is the cause of coagulation. Stirring the drawn 
blood and so keeping it in movement does not prevent but 
hastens its coagulation; and blood carefully imprisoned in 
a living blood-vessel, and so kept at reat, will not clot for a 
long time: not until the inner cout of the vessel begins to 
change from the want of fresh blood, Secondly, keeping the 
blood at the temperature of the Body hastens coagulation, 
and cooling retards it; blood received into an ice-cold vessel 
and kept surrounded with ice will clot more slowly than 
blood drawn and left exposed to ordinary temperatures. 
Finally, if the blood be collected over mercury from a 
blood-vessel, without having been exposed to the air even 
for an instant, it will still clot perfectly well. 

The formation of fibrin is then due to changes taking 
place in the blood itself when it is removed from the 
blood-vessels; clotting depends upon some rearrangement 
of the blood constituents, There is a good deal of reason 
to believe that what occurs is a breaking up of a number 
of the colorless corpuscles; that these then form fibrino- 
plastin and fibrin ferment, and, the fibrinogen and salts 
already existing in solution in the blood plasma, fibrin is 
formed. When fluids which contain no red corpuscles 
clot, as for instance vaccine lymph, the first threads of 
fibrin developed can be seen under the microscope to 
radiate from the pale corpuscles present. 

Relation of the Blood-Vessels to Coagulation. Asto the 
role of the vessels with respect to coagulation when the 
blood is flowing in them two views are held, between which 
the facts at present known do not permit a decisive judg- 
ment to be made. One theory is that the vessels actively 
prevent coagulation by constantly absorbing from the blood 
some substance, as for example the fibrin ferment, which 
may be supposed constantly to develop, and the presence 
of which is a necessary condition for the formation of 
fibrin. The other view is that the blood-vessels are passive 
and completely neutral. They simply do not excite those 
changes in the blood constituents which give rise to the 





COMPOSITION OF THE BLOOD, 57 


formation of fibrinoplastin or the ferment, while foreign 
bodies in contact with the blood do excite these changes 
and 30 cause coagulation. 

Whatever the part which the blood-vessels play, it is only 
exhibited when their inner surfaces are healthy and unin- 
jured. If this lining be ruptured or diseased the blood 
clots. Accordingly, after death, when post-mortem changes 
have affected the blood-vessels, the blood clots in them; 
‘but often very slowly, since the vessels only gradually alter. 
If the Body be left in one position after death, the clots 
formedin the heart have often a marked buffy coat, because 
the corpuscles have had a long time to sink in the plasma 
before coagulation occurred. In medico-legal eases it is 
thus sometimes possible to say what was the position of a 
corpse for some hours after death, although it has been 
subsequently moved. The lymph clots like the blood, but 
not so firmly; since it contains no red corpuscles, the clot 
formed is of course colorless, 

Composition of the Blood. The average specific gravity 
of human blood is 1055. It has an alkaline reaction, 
which becomes less marked as coagulation occurs. About 
one half of its mass consists of moist corpuscles and the 
romainder of plasma. Exposed in a vacuum, 100 volumes 
of blood yield abont 60 of gas consisting of a mixture of 
oxygen, carbon dioxide, and nitrogen. 

Chemistry ofthe Serum. The blood plasma cannot well 
be examined as to its chemical constituents, since it clots 
under manipulation. The serum is, however, essentially 
blood plasma minus fibrin, and from an analysis of it we 
can draw conclusions as to the plasma. In 100 parts of 
serum there are about 90 parts of water, 8.5 of proteids, and 
1.5 of fats, salts, and other less-known solid bodies. Of 
the proteids present the most abundant is serum albumin, 
which agrees with egg albumin in coagulating when heated: 
#0 that serom when boiled sets into an opaqne white mass, 
just as the white of an egg does. Chemically, serum albu- 
min differs from egg albumin in being coagulated by ether; 
and physiologically, in the fact that although present in 
such large quantities in the blood, it does not pass through 





58 THE HUMAN BODY. 


the kidneys, whereas egg albumin when injected into the 
blood-vessels of an animal is rapidly excreted by those 
organs. In health the fats are only present in the serum 
in small quantity except after a meal at which fatty sub- 
stances have been eaten; serum obtained from the blood of 
an animal soon after such « meal is often milky in appear- 
ance from the fats present, instead of being perfectly color- 
less or pale yellow, and transparent as it is after fasting, 
'The salts dissolved in the serum are mainly sodium chloride 
und carbonate; but small quantities of sodinm, calcium, 
and magnesium phosphates are also present. 

Chemistry of the Red Corpuscles. In thesein the fresh 
moist state there are in 100 parts, 56 of water and 44 of 
solids. Of the solids about one per cent is salts, chiefly 
potassium phosphate and chloride. The remaining organic 
solids contain, in 100 parts, 90 of hemoglobin and about 8 
of other proteids; the residue consists of less well-known 
bodies, 

Chemistry of the White Corpuscles. Those yield be- 
sides much water, several proteids, some fats, glycogen 
(see Chap, XXVIII), and salts; and smaller quantities of 
other bodies. The predominant salts, like those of the red 
corpuscles, are potassium phosphates, 

Variations in the Composition of the Blood. Hygienic 
Remarks, The above statements refer only to the average 
composition of the healthy blood, and to its better known 
constituents. From what was said in the last chapter it is 
clear that the blood flowing from any organ will have lost 
or gained, or gained some things and lost others, when 
compared with the blood which entered it. But the losses 
and gains in particular parts of the Body are in such small 
amount as, with the exception of the blood guses, to elude 
analysis for the most part: and the blood from all parts 
being mixed up in the heart, they balance one another and 
produce a tolerably constant average. In health, however, 
the specific gravity of the blood may vary from 1045 to 
1075; the red corpuscles also are present in greater propor- 
tion to the plasma after a meal than before it. Healthy 
sleep in proper amount also increases the proportion of red 





BLOOD CORPUSCLES. 59 


corpuscles, and want of it diminishes their number as may 
be recognized in the pallid aspect of a person who has lost 
several nights’ rest. Fresh air and plenty of it has the 
same effect. 

‘The proportion of these corpuscles has a great import- 
ance since, a8 we shall subsequently see, they serve to carry 
oxygen, which is necessary for the performance of its func- 
tions. all over the Body, Anqmia is a diseased condition 
characterized by pallor due to Geficiency of red blood cor- 
puscles, und accompanied by languor and listlessness. It is 
not unfrequent in young girls on the verge of womanhood, 
and in persons overworked and confined within doors. In 
such cases the best remedies are open-air exercise and good 
food. 

Practically the composition of the blood 
may be thus stated: It consists of (1) plasma, consisting 
mainly of water containing in solution seram albumin, 
sodium aalts, smaller amounts of those of other metals, and 
extractives of which the most constant are urea, hreatin, 
and grape sugar; (2) red corpuscles, containing rather more 
than half their weight of water, the remainder being main- 
ly hemoglobin, other proteids, and potash salts; (3) white 
corpuscles, consisting of water, various proteids, glycogen, 
and potash salts; (4) gases, partly dissolved in the plasma 
or combined with its sodinm salts, and (oxygen) partly 
combined with the hemoglobin of the red corpuscles. 

Quantity of Blood. The total amount of blood in the 
Body is diflcult of accurate determination, It is, how- 
ever, about yy of the whole weight of the Body, so the 
quantity in a man weighing 75 kilos (165 Ibs.) is about 5.8 
kilos (12.7 Ibs.). Of this at any given moment about ono 
fourth would be found in the heart and big blood-vessels: 
and equal quantities in the capillaries of the liver, and in 
those of the muscles which move the skeleton; while the 
remaining fourth is distributed among the remaining parts 
of the Body. 

The Origin and Fate of the Blood Corpuscles. Tho 
white blood corpuscles vary so rapidly and frequently in 
namber in the blood that they must be constantly in pro- 





THE HUMAN BODY. 


cess of alteration or removal, and formation; their number 

ly increased by taking food, even more than that of 
the red, so that their proportion to the red rises, from 1 
to 1000 during fasting, to 1 to 250 or 300 aftor ® meal. 
They no doubt multiply to a certain extent by division 
while circulating in the blood, bnt the majority come from 
the lymphatic glands and similar structures (see Chap. 
XXIL) found in many parts of the Body, which con- 
tain many cells like pale blood corpuscles, and often in 
process of division. From these organs the corpuscles en- 
ter the lymph-vessele and are carried on into the blood. 
From the capillary blood-vessels many again migrate, and 
it is probable that these emigrants take part frequently in 
the repair or regeneration of injured tissues. Being un- 
differentiated and specialized to no line of work they are 
ready to take up any that comes to hand, and may be com- 
pared to the young men in a community who have not yet 
selected an occupation and are on the lookout for an open- 
ing. On the other hand there seems little doubt that a 
great many white corpuscles give rise to red ones, and this 
is perhaps to be regarded as their special function. The 
corpuscles of nearly all invertebrate animals are colorless 
only, although the blood plasma of some contains hwmo- 
globin in solution, Amphioxus, the lowest undoubted 
vertebrate animal (see Zoology), ulso possesses only colorless 
corpuscles in its blood. But higher and more complex ani- 
mals necd more oxygen, and as blocd plasma dissolves 
very little of that gus, they develop in addition the hmmo- 
globin-containing corpuscles which pick it up in the gills 
or lungsand carry it to all parts of the Body, leaving it 
where wanted (see Chap. XXV.). Incold-! blooded vertebrates 
the red corpuscles are not nearly so many in proportion as 
in the warm-blooded, which use far more oxygen. The 
older view was that the mammalian red corpuscle repre- 
sented the nucleus of one of the white, in which hwmoglo- 
bin had beon formed and from about which the rest of the 
corpuscle had disappeared. This, however, does not seem 
to be the case; but the pale corpnscle developa or forms 
hemoglobin in its cell protoplasm, and flattens and as- 





61 


sumes the form of a red corpuscle,while its nuclens disap- 
pears. Occasional ttunsitional forms between the pale and 
the red corpuscle are seen in blood when examined with 
the microscope; and if blood be put fresh on # cold slide 
and examined in a cold room these transitional forms are 
more numerous, since at ordinary temperatures they very 
rapidly break down and fall to pieces when blood is drawn. 

How long an individual red corpuscle lasts is nob known, 
nor with certainty how or when it disappears. There is, 
however, some reason to believe that a great many are de- 
stroyed in the spleen (see Chap. XXIT.). 

Chemistry of Lymph. Lymph is « colorless fluid when 
pure, feebly alkaline, and with « specific gravity of about 
1045. It may be described as blood minus its red corpuscles 
und considerably dilated, but of course in various parts of 
the Body it will contain minute quantities of substances 
derived from neighboring tissues. It contains a considera- 
ble quantity of carbon dioxide gas which it gives up ina 
vacuum, but no oxygen, since any of that gas which passes 
into it by diffusion from the blood is immediately picked 
up by the living tissues among which it flows, 





CHAPTER VI. 
THE SKELETON. 


Exoskeloton and Endoskeleton. The skeleton of an 
animal includes all its hurd protecting or supporting parts, 
and is met with in two main forms in the animal kingdom. 
First as un exoskeleton developed in connection with either 
the superficial or deeper layer of the skin, and represented 
by the shell of a clam, the scales of fishes, the horny plates 
of a turtle, the bony plates of an armadillo, and the feathers 
of birds. In man the exoskeleton is but slightly developed, 
but it is represented by the hairs, nails, and teeth; for al- 
though the latter lie within the mouth, the study of devel- 
opment shows that they are developed from un offshoot of 
the skin which grows in and lines the mouth long before 
birth. Hard parts formed from structures deeper than 
the skin constitute the endoskeleton, which in man is highly 
developed and consists of a great many bones und cartilages 
or gristles, the bones forming the mass of the hard fram: 
work of the Body, while the cartilages finish it off at vari- 
ons parts, This framework is what is commonly meant by 
the skeleton, and it primarily supports the softer parts and 
is also arranged so us to surround cavities in which delicate 
organs, as the brain, heart, or spinal cord, may lie with 
safety. The skeleton thus formed, however, is completed 
und supplemented by another made of the connective tissue, 
which not only, in the sha tough bands or ligaments, 
ties the bones and cartilages together, but also in various 
forms pervades the whole Body as a sort of subsidiary 
skeleton running through all the soft organs, forming net~ 
works of fibres around other constituents; so that it 
makes, as it were, a microscopic skeleton for the individual 
modified cells of which the Body is so largely composed, 





a 
AXIAL SKELETON, 63 


and also forms partitions between the muscles, cases for 
snch organs ax the liver and kidneys, and sheaths around 
the blood-vessels. ‘The bony and cartilaginous framework 
with its ligaments might be called the skeleton of the 
organs of the Body, and this finer supporting meshwork the 
skeleton of the tissues. Besides forming a support in the 
substance of various organs, the connective tissue is also 
often laid down as a sort of packing material in the crevices 
between them; and so widely is it distributed everywhere 
from the skin ontside to the lining of the alimentary canal 
inside, that if some solvent could be employed which would 
corrode away all the rest and leave only this tissue, a very 
perfect model of the whole Body would be left; something 
like a ‘skeleton leaf,” but fur more minute in its tracery. 

The Bony Skeleton (Fig. 13). If the hard framework 
of the Body were joined together like the joints and beams of 
a house, the whole mass would be rigid; its parts could not 
move with relation to one another, and we would be un- 
able to raise 1 hand to the mouth or put one foot before 
another. To allow of mobility the bony skeleton is made 
of many separate pieces which are joined together, the 
points of union being called articulations, and at many 
places the bones entering into an articulation are movably 
hinged together, forming what are known as joints. The 
total number of bones in the Body is more than two 
hundred in the adult; and the number in children is still 
greater, for various bones which are distinct in the child 
(and remain distinct throughout life in many lower animals) 
grow together 90 as to form one bone in the full-grown 
man. The adult bony skeleton may be described as con- 
sisting of an axial skelelon found in the head, neck, and 
trunk; and an appendicular skeleton, consisting of the 
bones in the limbs and in the arches (w and s, Fig. 13) by 
which these are carried and attached to the trunk, 

Axial Skeleton, The axial skeloton consists primarily 
of the vertebral column or spine, a side view of which is 
represented in Fig. 14. The upper part of this column is 
composed of twenty-four separate bones, each of which isa 
vertebra, At the posterior part of the trank, beneath the 








Fi, 14.—The bony nnd cartilaginous Pia, 1—Side view of the 
skeleton. spinal column. 


Bo 


VERTEBRA. 65 


movable vertebre, comes the sacrum (S 1), made up of 
five vertebrw, which in the adult grow together to form 
one bone, and below the sacrum is the coceyx (Co 1-4), 
consisting of four very small tail vertebre, which in ad- 
vanced life als} unite to form one bone. 

On the top of the vertebral column is borne the skull, 
made up of two parts, viz., # great box above which in- 
closes the brain and is called the cranium, and a large 
number of bones on the ventral side of this which form the 
skeleton of the face. Attached by ligaments to the under 
side of the cranium is the Ayoid done, to which the root of 
the tongue is fixed, 

Of the twenty-four separate vertebre of the adult the 
seven nearest the skull (Fig. 14, €1-%) lie in the neck 
and are known as the cervical vertebra. These are fol- 
lowed by twelve others which have rids attached to them 
(see Fig. 13) and lie at the back of the chest; they are the 
dorsal vertebra (D 1-12). The ribs (Fig. 25 *)are slender 
curved bones. attached by their dorsal ends, called their 
Heads, to the dorsal vertebre and ranning thence round the 
sides of the chest. In the ventral median line of the lat- 
ter is the breast-bone or siernum (d, Fig 13). Exch rib 
near its sternal end ceases to be bony and is composed of 
carti 

These parts—skull, hyoid bone, vertebral column, ribs, 
and sternum—constitute the axial skeleton, and we have 
now to consider its parts more in detail. 

‘The Dorsal Vertebrw. If a single vertebra, say the 
eleventh from the skull, be examined carefully it will be 
found to consist of the following parts (Figs. 15 and 16): 

First a bony mass, @, rounded on the sides and flattened 
on each end where it is turned towards the vertebra above 
und below it. This stout bony cylinder is the ‘ dody” or 
tentrum of the vertebra, and the series of vertebral bodies 
(Pig. 14) forms in the truant that bony partition between 
the dorsal and ventral cavities of the body spoken of in 
Chapter I. To the dorsal side of the body is attached an 
arch—the neural arch, A, which with the back of the body 
incloses a space, Fv, the neural ring. In the tube formed 


*P. 78. 








66 THE HUMAN BovY. 


by the rings of the successive vertebrae lies the spinal cord. 
Projecting from the dorsal side of the neural arch is a long 
bony bar, Ps, the spinous process; and the projectionsof these 

from the various vertebra: can be felt through the 
skin all down the middle of the back. Henive the name of 
spinal column often given to the whole back-bone. 

Six other processes arise from the arch of the vertebra: two 
project forwards, i.e. towards the head; these, Pas, are the 
anterior articular processes and have « smooth surface, 
covered with cartilage on their dorsal sides. A pair of sim- 














Fro, 1% Pra, 
Fro. 15.—A dorsal vertebra seen from behind, Ke. the end turned from the 


Fip, 16,—Two dorsal vertebras viewed from the joft side, and tn thelr aataral 
relative postoak 0, the ural arch: 1 Pe ple 
nows 


5 fas, anterior ay progeent ‘ad, pouvoir articuler prossbes 
Ft, unnsrerse proceas: #7, fnost for articulation With the tubercle of n Hib: 
Pet, Fei, articular surfaces on the centrum for articulation with a rib, 





. 
ilar posterior articular processes, Pai, rans back from the 
neural arch, and these have smooth surfaces on their ven- 
tral aspects. In the natural position of the vertebra, the 
smooth surfaces of its anterior articular processes fit upon 
the posterior articular processes of the vertebra next in 
front, forming a joint, and the two processes are united 
by ligaments. Similarly its posterior articular processes 
form joints (Fig. 16) with the anterior articular processes 
of the vertebre next behind. 





SEGMENTATION OF SKELETON. ne 


The remaining processes are the /ransverse, Pt, which 
ran outwards and a little dorsally. Each of these has a 
smooth articular surface, #?, near its outer end. 

On the ‘* body” are seen two articular gurfaces on each 
side: one, Fes, at its anterior, the other, Fri, at its poste- 
rior end, and both close to the attachment of the neural 
arch. Each of these surfaces formed with corresponding 
areas on the yertebrie in front and behind a pit into which 
the end of a rib fitted and the rib attached in this way to 
the anterior part of the ‘ body” also fitted on, a little way 
from its dorsal end, to the articular surface at the end of 
the transverse process, 

‘The Segments of the Axial Skeleton. If a dorsal verte- 
bra, say the first (Fig. 17), be detached with the pair of ribs, 
Ov, belonging to it and the 8 
bit of the sternum, 8, to 
which these ribs are fixed 


ventrally, we would find a 
Cy 


bony partition formed by 
the body of the vertebra, 
lying between two arches 


which surround cavities, 


The dorsal cavity inclosed ¥ 


by the * body” and ‘neural 
arch” contained originally 
part of the spinal cord. The 


Fra, 17.— Diagrammatic peprmsantatl 
o€ a aagment of the wxial stpleton, 

m, Tibs articulating abore 
‘with the body aad transverse proceas of 


the vertebra: 5, the breast-bono. The 
ightar-shaded part betwnen 8 and C is 


other ring, made up by the Lighter baa ps 


body of the vertebra dor- 
sally, the sternum ventrally, and the ribs on the sides, sur- 
rounds the chest cavity with its contents, All of these 
» parts together form a typical segment of the axial skeleton, 
which, however, only, attains this completeness in the 
thoracic region of the trunk. In the skull it is greatly 
modified; and in the neck and the lower part of the trunk 
the ribs are either absent or very small, appearing only as 
processes of the vertebne; and the sternal portion is wanting 
altogether. 
Nevortheless we may regard the whole axial skeleton as 
made up of a series of such segments placed one in front of 











68 THE HUMAN BODY, 


the other, but having different portions of the complete 
segment much modified or rudimentary, or even altogether 
wanting in some regions. Purts which in this sort of way 
really correspond to one another though they differ in de- 
tail, which are so to speak different varieties of one thing. 
are said in anatomical language to be homologous to one an- 
other; and when they succeed one wnother in a row, as the 
trunk segments do, the homology 1s spoken of as serial. 

‘The Cervical Vertebre. In the cervical region of the 
vertebral column the bodies of the vertebre are smaller 
than in the dorsal, but the arches are larger; the spinous 
processes are short and often bifid and the transverse pro- 
cesses appear perforated by a canal, the vertebral foramen. 

The bony bar bounding 

__¢n this aperture on the ventral 

side, however, is in reality 

a very small rib which has 

grown into continuity with 

the body and trae transverse 

) process of the vertebra, al- 

4 though separate in very early 

verviral foramen Puanterorarte: life: the transverse process 

Herecyoe proper bounds the vertebral 

foramen dorsally. In this latter during life rans an artery, 
which ultimately enters the skull cavity, 

‘The Atlas and Axis, ‘The first and second cervical ver- 
tebre differ considerably fromthe rest. The first, or atlas 
(Fig. 19), which carries the head, has a very smull body, 
Aq, and a large neural ring. This ring is subdivided by a 
cord, or the ¢ransverse ligament, L, into a dorsal moiety iy 
which the spinal cord lies and a ventral into which the 
bony process D projects. This is the odontoid process, and 
arises from the front of the axis or second cervical vertebra 
(Fig. 20). Around this peg the atlas rotates when the head 
is turned from side to side, carrying the skull (which ar- 
ticulates with the large hollow eurfaces Fas) with it. 

The odohtoid process really represents a large piece of 
the body of the atlas which in early life separates from its 
own vertebra and grows on the axis. 


‘al 








SACRUM. 69 


‘Tho Lumbar Vortobrw (Fig. 21) are the largest of all 
the movable vertebre and have no ribs attached to them. 
Their spines are short and stout and lie in a more horizontal 


Hap Pas 


Te Ap 


Fro. 19 re 0. 


M9. 9.—The atlas. Fig. £2, body of atlas; D, eden 
cose; Fas, facet on front of atlas with vith which the abell artiealatser and it 
anterior irticular surface of axis; L, transverse ligament: vt, vertebral 
men, 


plane than those of the vertebre in front. The articular 
and transverse processes are also short and stout. 

The Sacrum, which is represented along with the last 
lumbar vertebra in Fig. 22, consists in the adult of a single 
bone; but cross-ridges on its ventral surface indicate the 


Fra, 21 —A lumbar vertebra mn from the left side, Pa spinous proces: 
Pus, anterior articular proces; Pus, posterior m1 process, 


limits of the five separate vertebre of which it-is composed 
in childhood. It is somewhat triangular in form, its base 
being directed upwards and articulating with the under 





id THE HUMAN BODY. 


surface of the body of the fifth lumbar vertebra. On its 
sides are large surfaces to which the arch bearing the lower 


Fio. 22.—Tho last lumbar vertebra and the sacrum seen from the ventral side. 
Pro, anterior sacral foramina, 


limbs is attached (see Fig. 13). Its ventral surface is con- 

cave and smooth and presents four pairs of anterior sacral 
Soramina, Fea, which communicate with 
the neural canal. Its dorsal surface, convex 
and roughened, has four similar pairs of pos- 
terior sacral foramina, 

The coceyx (Fig. 23) calls for no special 
remark. ‘The four bones which grow togeth- 
er, or ankylose, to form it represent only the 
bodies of vertebre, and even that imperfectly. 
It is in reality a short tail, although not visi- 
ble as such from the exterior. 

The Spinal Column asa Whole. The vertebral columu 





SPINE AS A WHOLE, vel 


is ina man of average height about twenty-eight inches 
long. Viewed from one side (Hig. 14) it presents four cur- 
vatures ; one with the convexity forwards in the cervical 
region is followed, in the dorsal, bya curve with its concay- 
ity towards the chest. In the lumbar region the curve has 
again its convexity turned ventrally, while in the sacral and 
eoccygeal regions the reverse is the case. ‘These curvatures 
give the whole column 4 good deal of springiness such as 
would be absent were it a straight rod, and this is farther 
secured by the presence of compressible elastic pads, the 
tufervertebral disks, made up of cartilage and connective 
tissue, which lie between the bodies of those vertebra 
which are not ankylosed together, and fill up completely 
the empty spaces left between the bodies of the vertebra in 
Fig. 14. By means of these pads, moreover, a certain 
amount of movement is allowed between each pair of ver- 
tebre ; and so the spinal column can be bent to consider- 
able extent in any direction ; while the movement between 
any two yertebrie is so limited that no sharp bend can take 
place at any one point, such as might tear or injure other- 
wise the spinal cord contained in the neural canal. The 
amount of movement permitted is greatest in the cervical 
region. 

In the case of the movable vertebrw, where the arch 
joins the body on each side, it is somewhat narrowed; this 
narrowed stalk being known as the pedicle (li, Fig. 16), 
while the broader remaining portion of the arch is its lam- 
ina. Between the pedicles of two contiguous vertebrae 
there are in this way left apertures, the intervertebral holes 
which form a series on cach side of the vertebral column, 
and one of which, Fi, is shown between the two dorsal 
yertebre in Fig. 16. Through these foramina nerves run 
out from the spinal cord to various regions of the Body. 
‘The sacral foramina, anterior and posterior, are the repro- 
sentatives of these apertures, but modified in arrangemont, 
on account of the fusion of the arches and bodies of the 
vertebrw between which they lie. 

Sternum. ‘The sternum or breast-bone (Fig. 24 and d, 
Fig. 13) is wider from side to side than dorso-ventrally. Tt 








mR THE HUMAN BODY, 


consists in the adult of three pieces, and seen from the yen 
tral side has somewhat the form of a dagger. The picce 
M nearest the head is called the handle or menubrivm, 
and presents anteriorily a notch, Jel, on each side, with 
which the collar-bone articulates (uv, Fig. 13); on each side 
are two other notches, Ze 1 and Je 2, to which the sternal 
ends of the first and second ribs are attached. The middle 
piece, C, of the sternum is called the Jody; it completes 
the notch for the second rib and has on 
its sides others, Ze 8-7, for the third, 
fonrth, fifth, sixth, and seventh ribs. 
The last piece of the sternum, P, is 
called the ensiform or xiphoid process; 
it is composed of cartilage, and has no 
ribs attached to it. 

‘The Ribs (Fig. 25). There aretwelve 
pairs of ribs, each being a slender curved. 
bone attached dorsally to the body and 
transverse process of a vertebra in the 
manner already mentioned, and con- 
tinued ventrally by a costal cartilage. 
In the case of the anterior seven pairs, 
the costal cartilages are attached diroct- 
ly to the sides of the breast-hone; the 
é next three cartilages are each attached 
3 to the cartilage of the preceding rib, 
Fro. %—The stemum While the cartilages of the tenth and 

Tania, C tote, twelfth ribs are quite unattached ven- 
aineld 5 i, trally, 0 these fe called the free or 
Je, 1-7, notches for the floating ribs. The convexity of each 
Ea naga curved rib is turned outwards so as to 
give roundness to the sides of the chest and increase its 
cavity, and each slopes downwards from its vertebral at- 
tachment, so that its sternal end is considerably lower than 
its dorsal. 

Tho Skull (Fig. 26) consists of twenty-two bones in 
the adult, of which eight, forming the cranium, are ar- 
ranged so as to inclose the brain-case and protect the 
uuditory orgun, while the remaining fourteen support 








THE SKULL. 73 


the face and surround the mouth, the nose, and the eye- 
sockets. 


Fro, £5.—Tho ribs of the loft side, with the dorwal and two lumbar vertebra, 
tho rib cartilages an 


Cranium. The cranium is a box with a thick floor and 
thinner walls and roof. Its floor or base represents in the 
head (as is depicted diagrammatically in Fig. 2) that par- 





THE HUMAN BODY. 


tition between the dorsal and ventral cavities which in the 
trunk is made up of the bodies of the yertebre. In very 
early life it presents in the middle line a series of four 
bones, the basi-occipital, basi-sphenoid, presphenoid, and 


four vertebre, and 
which inclogso the skull ¢ which may be likened to 
an enlarged neural canal) on the sides and top. In the 





CRANIAL BONES. 


Human Body, however, these bones very soon ankylose 
with others or with one another; although they remain 
distinct throughout life in the skulls of very many lower 
animals, On the base of the skull, besides many small 
apertures by which nerves and blood-vessels pass in or out, 
is 4 large aperture, the foramen magaum, through which 
the spinal cord pagses in to join the brain. 

‘The cranial bones are the following: 

1, The occipital bone (Fig. 26, 
O) unpaired and having in it the 
foramen magnum. It is made 
up by the fusion of the basi-oc- 
cipital (Fig. 27) with other flatter 
bones, 2. The frontal bone (Fig. 
26, 7), leo unpaired in the adult, 
but in the child each half is a sep- 
urate bone. 3. A pair of thin plate- 
like paristal bones (Pig. 26, Pr) 
which meet one another along the 
middle line in the top of the 
skull, and roof in a great part of 
the cranial cavity. 4. A puir of 
temporal bones (Fig. 26, T'), once 
on cach side of the skull beneath At the tower part of tha figure 
the parietal. On each temporal otal (hots ta parte 
bone is a large aperture leading 
into the ear cavity, the essential 
parts of the organs of hearing { 
being contained in these bones. 
5. The sphenoid bone, made up 
hy the union of the dasi-sphe- 
void and presphenoid (lying on the base of skull in front 
of the basi-oecipital) with one another and with flatter 
bones, is seen partly (Fig. 26, 8) on the sides of the cranium 
in front of the temporals. 6. The efhmoid, like the spho- 
noid, single in the adult, is really made up by the union of 
asingle median dasi-ethmoid with a pair of lateral bones. 
Tt closes the skull cavity in front, and lies between it and 
the top of the nasal chambers, being perforated by many 








76 THE HUMAN BODY, 


small holes through which the nerves of smell pass. A. 
little bit of it is seen on the inner side of the eye-socket at 
E in Fig. 26. * 

Facial Skeloton. ‘The majority of the face bones are in 
pairs ; two only being single and median. One of these is 
the lower jaw-bone or inferior maxilla (Pig. 26, Md); the 
other is the vomer, which forms part of the partition 
between the two nostrils. 

‘The paired face-bones are: 1. The maxilla, or upper jaw- 
bones (Jfr, Fig. 26), one on each side, carrying the upper 
row of teeth and forming « great part of the hard palate, 
which separates the mouth from the nose. 2, The pala- 
tine bones, completing the skeleton of the hard palate, and 
behind which the nose communicates by the posterior nares 
(Fig. 27) with the throat cavity, so that air can pass in or 
out in breathing. 3. The malar bones, or cheek-bones, 
(Z, Fig, 26), lying bencath and on the outside of the orbit 
on each side, 4. The nasal bones (N, Fig, 26), roofing in 
the nose. 5. The lachrymal bones (ZL, Fig. 26), very small 

_ and thin and lying between the nose and orbit. 6. The 
inferior turbinate bones lie inside the nose, one in each 
nostril chamber, 

Tho Hyoid. Besides the cranial and facial bones there 
is, as already pointed out, one other, the hyoid (Fig. 28), 
which really belongs to the skull, although it lies in the 
neck. It can be felt in front of the throat, just above 
“ Adam’s apple.” The hyoid bone is U-shaped, with its 

convexity turned ventrally, and consists 
of a body and two pairs of processes 
called cornua, Tho smaller cornua (Fig. 
28, 3) are attached to the skull, close to 
T in Fig. 26, by long ligaments. These 
vane Sheng ligaments in many animals are represent- 
icreat cornu; 8, ed by bones, 80 thut the hyoid, with them, 
forms a bony arch attached to the base 
of the skull much as the ribs are attached to the bodies of 
the vertebrae. In fishes, behind this hyoidean arch come 
several others which bear the gills; and in the very young 
Human Body these also are represented, though they almost 





SHOULDER GIRDLE, Ww 


entirely disappear long before birth. The hyoid, then, 
with its cornua and ligaments answers pretty much to a 
gill-arch, or really to parts of two gill-arches, since the 
great and small cornua belong to originally separate arches 
present at an early stage of development. It is a remnant 
of a structure which has no longer any use in the Human 
Body; but in the young frog tadpole parts answering to 
it carry gills and have clefts between them which extend 
into the throat just as infishes. The gills are lost after- 
wards and the clefts closed up when the frog gets its lungs 
and begins to breathe by them. In the embryonic human 
being these gill-clefts are also present and several more 
behind them, but the arches between them do not bear 
gills, and the clefts themselves are closed long before birth. 
As they have no use their presence is hard to account for; 
those who accept the doctrine of Evolution regard them as 
developmental reminiscences of an extremely remote ances- 
tor in which they were of functional importance somewhat 
#5 in the tadpole; of conrse this does not mean that men 
were developed from tadpoles. 

The Appendicular Skeleton. This consists of the 
shoulder girdle and the bones of the fore limbs, and the 
pelvic girdle and the bones of the posterior limbs, The two 
supporting girdles in their natural position with reference 
to the trunk skeloton are represented in Fig, 29. 

The Shoulder Girdle, or Pectoral Arch. This is made 
up on each side of the scapula or shoulder-blade, and the 
clavicle or collar-bone. 

The scapula (S, Fig. 29) is a flattish triangular bone 
which can readily be felt on the back of the thorax. It is 
not directly articulated to the axial skeleton, but lies im- 
bedded in the muscles and other parts outside the ribs on 
each side of the vertebral column. From its dorsal side 
arises a crest to which the outer end of the collar-bone is 
fixed, and on its outer edge is a shallow cup into which the 
top of the arm-bone fits; this hollow is known us the glenoid 


fossa, 
‘The collar-bone (CO, Fig. 29) is cylindrical and attached 











7 THE HUMAN BODY. 


at its inner end to the sternum as shown in the figure, fit- 
ting into the notch represented at Jel in Fig. 24. 

The Fore Limb. In the limb itself (Fig, 30) are thirty 
bones. The largest, a, lies in the upper arm, and is called 





Fra, £2.—The skeleton of the trunk and the limb arches seen from the front. 
C, clavicle; 8, scapula; Or, innominate bone attached to the side of the sseram 
dorsally and inecting it flow at the pubic symphyss in the ventral median 


the Awmerus. At the elbow the humerus is succeeded by 
two bones, the radius and ulna, and b, which lie side by 
side, the radius being on the thumb side. At the distal 
ends of these bones come eight small ones, closely packed 





PELVIC GIRDLE. 


and forming the wrist, or carpus. Then come five cylindri- 
cal bones which can be felt through the soft parts in the 
palm of the hand; one for the thumb, and one for each of 
the fingers. These are the metacarpal bones, and are dis- 
tinguished as first, second, third, and so on, the first being 
that of the thamb, In the thumb itself are two bones, and 
in each finger three, arranged in rows one after the other; 
these bones are all called phalanges. 

Tho Pelvic Girdle (Fig. 29). This consists of a large 
bone, the ox innominatum, Ov, on each side, which is 
firmly fixed dorsally to the sacrum and meets its fellow in 
the middle yentralline. In the child each 03 innominatum 
consists of three bones, viz., the ilium, the ischium, and 
pubis. Where these three bones meet and finally ankylose 
there is a deep socket, the acetabulum, into which the head 
of the thigh-bone fits (see Fig. 13). Between the pubicand 
ischial bones is the largest foramen in the whole skeleton, 
known as the doorlike or thyroid foramen. The pubic 
bone lies above and the ischial below it. ‘The ilinm forms 
the upper expanded portion of the os innominatum to 
which the line drawn from Ov in Fig. 29 points. 

Tho Hind Limb. In this there are thirty bones, asin the 
fore limb, bat not quite similarly arranged; there being one 
less at the ankle than in the wrist, and one at the knee 
not present at the elbow-joint. The thigh-bone or femur 
(a, Fig. 31) is the largest bone in the body and extends 
from the hip to the knee-joint, It presents above a large 
rounded ead which fits into the acetabulum and, below, it 
is also enlarged and presonts smooth surfaces which meet 
the bones of the leg. These latter are two in number, 
known as the fidia, ¢, or shin-bone, and fibula, d; the tibia 
being on the great-toe side. In front of the knee-joint is 
the knee-cap, or patella, b. 

At the distal end of the leg-bones comes the foot, con- 
sisting of ¢arsus, metatarsus, and phalanges. The tarsus, 
which answers to the carpus of the fore limb, is made up of 
seven irregular bones, the largest being the heel-bone, or 
caleaneum, i. The metatarsus consists of five bones lying 
#de by side, and each carries a toe at its distal end. In 








80 THE HUMAN BODY. 


the great toe (or hallux) there are two phalanges, in each 
of the others three, arranged as in the fingers, but smaller. 
Comparison of the Anterior and Posterior Limbs, It 








Fro. 1. S 
Fro. 30.—The bones of the arm, a, humerus; b, ulna: ¢ radius: d, the carpus: 
¢; the Ofth metacarpal; J. the three phalanges of the feh digit Gitte finger), 
@,.mhe ph inges of the pollex (thumb), 
0. 


—Bones of the log. a, femur; D, patella: ¢. Wibia: d. Mbulay A, caloa 
neum; ¢, remaining taraal bones: /, metatarsal bones; g, phalanges, 





is clear that the skeletons of the arm and leg correspond 
pretty closely to one another. Both are in fact quite alike 
in yery early life, and their differences at birth depend upon 


HOMOLOGIES OF THE LIMBS, BL 
their diverging in different ways as they develop from 


their primitive simplicity; as both may be regarded as 
modifications of the same original structure, they are ho- 


ca 
a 7 


keleton of the arm and leg. #7. the humerus; O¥, its articular 


Tro The 
head which fila into the pore fossa of the scapula; U. the ulna; R, tho 


ra 
hans ©, the olecranon; Pe, the femur; P, the patella, J*, the fbula; 7, the 


mologous. "The pelvic girdle clearly corresponds generally 
to the pectoral arch, the tibia and fibula to the radius and 











8 THE HUMAN BODY, 


ulna ; the five metatarsal bones to the five metacarpal, and 
the phalanges of the toes to those of the thumb and fingers, 
On the other hand, there is in the arm no separate bone 
at the elbow-joint corresponding to the patella at the knee, 


but the ulna bears above a bony process, the olecranon (O, 


Fig. 32), which at first is a sepurate bone and is the rep- 
resentative of the patella. There are in the carpns eight 
bones and in the tarsus but seven. The astragalus of the 
tarsus (Ta, Fig. 35) represents /wo bones which, however, 


ecg? 3—Diagram showing the relation of the pectoral arch to the axial skel- 


have grown together. The elbow-joint bends forwards and 
the knee-joint backwards, 

Comparing the limbs as a whole, greater differences come 
to light, differences which are 
mainly correlated with the 
different uses of the two 
limbs. ‘The arms, serving as 

@ prehensile organs, have all 
their parts as movable as is 
consistent with the requisite 

= maaior! ». Strength, while the lower 

sent of the pol rch to the ail limbs, having to bear the 
whole weight of the Body, 

require to have their parts mnch more firmly knit together. 

Accordingly we find the shoulder girdle, represented red in 

the diagram (Fig. 33), only directly attached to the axial 
skeleton by the union of the inner ends of the clavicles with 
the sternum, and cupable of considerable independent move- 
ment, as seen, for instance, in ‘* shrugging the shoulders.” 
The pelvic arch, on the contrary, is firmly and immovably 








HAND AND FOOT COMPARED. 88 


fixed to the sides of the sacrum. The socket of the scapula, 
into which the head of the humerus fits, is very shallow 
and allows a far greater range of movement than is per- 
mitted by the deeper socket on the pelvis, into which the 
head of the femur fits. Further, if we hold the right 
humerus tightly in the left hand and do not allow it to 
more, we can still move the forearm bones so aa to turn 
the palm of the hand either up or down: no such moyve- 
ment is possible between the tibia and fibula. Finally, in 
the foot the bones are much less moyable than in the 
hand, and are arranged so as make a springy arch (Fig. 35) 
which bears behind on the caleaneum, Ca, and in front on 
the distal ends of the tarsal bones, Os; and over the crown 
of the arch, at Za, is the surface with which the leg-bones 


wurace for bia onthe natragaias; G6: the suold banat “tH 7H artioalnn 
articulate and on which the weight of the Body bears in 
standing. 
The toes, too, ure far less movable than the fingors, and 
this difference is especially well marked between the great 
toe and the thumb, The latter can be made to meet each 
of the finger-tips and so the hand can seize and manipulate 
very small objects, while this power of opposing the first 
digit to the rest is nearly absent in the foot of civilized 
man. In children, however, who have never worn boots, 
and in savages, the great too is far more movable, though it 
never forms as complete a thumb as in many apes, which 
use their feet, as well as their hands, for prehension. By 
practice, however, our own toes can be made much more 








84 THE HUMAN BODY. - 


mobile than they usually are, so that the foot can to a 
certain extent replace the hand; as has been illustrated in 
the case of persons born without hands who have learned to 
write and paint with their toes. 

Peculiarities of the Human Skeleton. Those are largely 
connected with the division of labor between the fore and 
hind limbs referred to above, which is carried farther in 
man than in any other creature. Even the highest apes 
frequently use their fore limbs in locomotion and their 
hind limbs in prehension, and we find accordingly that 
anatomically they present less differentiation of hand and 
foot. The other more important characteristics of the 
human skeleton are correlated for the most part with the 
maintenance of the erect posture, which is more complete 
and habitual in man than in the animals most closely allied 
to him anatomically. These peculiarities, however, only 
appear fully in the adult. Tn the infant the head is pro- 
portionately larger, the curves of the vertebral column are 
nearly absent, and the posterior limbs are relatively very 
short. In all these points the infant approaches more 
closely to the ape, and they all combine to give the centre 
of gravity of the Body a comparatively very high position 
and to render the maintenance of the erect posture difficult 
and insecure. The subsequent great relative length of the 
posterior limbs, which grow digproportionately fast in 
childhood as compared with the anterior, makes progression 
on them more rapid by giving a longer stride and at the 
same time makes it almost impossible to go on ‘all fours’® 
except by crawling on the hands and knees. In other Pri- 
inates this disproportion between the anterior and posterior 
limbs does not occur to nearly the same extent. 

In man the skull is nearly balanced on the top of the 
vertebral column, the occipital condyles which articulate 
with the atlas being about its middle (Fig. 27*),so that but 
little effort is needed to keep the head ereet. In four-foot~ 
ed beasts, on the contrary, the skull is carried on the front 
end of the horizontal vertebral column and needs special 
ligaments to sustain it. For instance, in the ox and sheep 
there is » great elastic cord running from the cervical ver- 


*P. 7. 








CHARACTERISTICS OF WUMAN SKELETON. 85 


tebra to the back of the skull and helping to hold up the 
head. Even in the highest apes the skull does not balance 
on the top of the spinal column; the face part is much 
heayier than the back, while in man the face parts are rela- 
tively smaller and the cranium larger, so that the two 
nearly equipoise. To keep the head erect and look things 
straight in the face, ‘like a man,” is for the apes far more 
fatiguing, and so they cannot long maintain that position, 

The human spinal column, gradually widening from the 
neck to the sacrum, is well fitted to sustain the weight of 
the head, upper limbs, etc., carried by it, and its curvatures, 
which are peculiarly human, give it considerable elasticity 
combined with strength. The pelvis, to the sides of which 
the lower limbs are attached, is proportionately very broad 
in man, so that the balance can be more readily maintained 
during lateral bending of the trunk, The arched instep 
and broad sole of the human foot are also very character- 
istic. The majority of four-footed beasts, as horses, walk 
on the tips of their toes and fingers, and those animals, as 
bears and apes, which like man place the tarsus also on 
the ground, or are plantigrade in technical language, have 
a much less marked arch there, The vaulted human tar- 
sus, composed of a number of small bones, each of which 
can glide a little over its neighbors, but none of which can 
move much, is admirally calculated to break any jar which 
might be transmitted to the spinal column by the contact 
of the sole with the ground at each step. A well-arched 
instep is therefore justifiably considered a beauty ; it makes 
progression easier, and by its springiness gives elasticity to 
the step. In London flat-footed candidates for appoint- 
ment as policemen are rejected, as they cannot stand the 
fatigue of walking the daily “ beat,” 





CHAPTER VII. 


THE STRUCTURE AND COMPOSITION OF BONE. 
JOINTS. 


Gross Structure of the Bones. The bones of the Body 
have all a similar structure and composition, but on ac- 
count of differences in shape they are divided by anato- 
mists into the following groups: (1) Long bones, more 
or less cylindrical in form, like the bones of the thigh and 
arm, leg and forearm, metacarpus, metatarsus, fingers 
and toes. (2) Tabular bones, in the form of expanded 
plates, like the bones on the roof and sides of the skull, and 
the shoulder-blades. (3) Short bones ; rounded or angular 
in form and not much greater in one diameter than in 
another, like the bones of the tarsns and carpus, (4) Jr- 
regular bones, including all which do not get well into any 
of the preceding groups,and commonly lying in the middle 
line of the Body and divisible into two similar halves, as 
the vertebrw. Living bones have « bluish-white color and 
possess considerable elasticity, which is best seen in long 
slender bones such as the ribs, 

To get a general idea of the structure of a bone, we may se- 
lect the humerus. Externally in the fresh state it is covered 
by a dense white fibrous membrane very closely adherent to 
it and containing a good many small blood-vessels. 
‘This membrane is called the periosteum; on its under side 
new osseous tissue is formed while the bone is still growing, 
and all through life it is concerned in maintaining the nu- 
trition of the bone, which di it is stripped off. The 
periosteum covers the whole surface of the bone except its 
ends in the elbow and shoulder joints; the surfaces there 
which come in contact with other bones and glide over them 





STRUCTURE OF A BONE. 87 


in the movements of the joint have no periosteum, but are 
coyered by a thin layer of 
gristle, known as the articn- 
lar cartilage. Very early in 
the development of the Body 
the bone in fact was repre- 
sented entirely by cartilage; 
but afterwards nearly all this 
was replaced by osseous tis- 
suc, leaving only a thin carti- 
laginous layer at the ends. 

The bone itself, Fig. 36, 
consists of a central nearly 
cylindrical portion or shaft, 
extending between the dot- 
ted lines z und z in the fig- 
ure, and two enlarged artic- 
ular extremities. 

On the upper articular ex- 
tremity is the rounded sur- 
face, Cp, which enters into 
the shoulder-joint, fitting 
against the glenoid cavity of 
the scapula; and on the low- 
er are the similar surfaces, 

Cpl and Tr, which articulate 

with the radius and ulna re- 

spectively, Besides carry- 

ing the articular surfaces, 

each extremity presents sey- 

eval prominences. On the 

upper are those marked Tmj 

and Tm (the greater and 

smaller trochanters), which 

give attachment to muscles; 

and similar eminences, the 

external and internal con- eit? ie trom, Heat a coe 
dyles, Eland Em, ave seen *™* 

on the lower end. Besides these, several bony. ridges 








THE HUMAN BODY. 


and rough patches on the shaft indicate places to which 
muscles of the arm were fixed. 
Internal Structure. If the bone be divided longitudi- 


Fra. a7 —A lone 


bong; 6, medullary 





parts. If a thin transv 


nally, it will be seen that its shaft is hollow, 
the space being known as the medullary 
cavity, and in the fresh bone filled with 
marrow. Fig. 37 represents a longitudi- 
nal section of the femur, which in this re- 
spect is quite similar to the humerns. 
‘The marrow cavity does not reach into the 
articular extremities, but there the bone 
has a loose spongy texture, except a thin 
layer on the surface. In the shaft, on the 
other hand, the oviter compact layer is 
much the thickest, the spongy or cancel- 
lated bone forming only a thin stratam im- 
mediately around the medullary cavity. 
To the naked eye the canvellated bone 
appears made up of a trellis-work of thin 
bony plates which intersect in all direc- 
tions and surround cavities rather larger 
than the head of an ordinary pin; the 
compact bone, on the contrary, appears 
to haye no cavities in it until it is exam- 
ined with a magnifying glass. In the 
spaces of the spongy portion lies, during 
life, a substance known as the red marrow, 
which is quite different from the yellow 
fatty marrow lying in the central cavity 
of the shaft. 

Microscopic Structure of Bone. ‘The 
microscope shows that the compact bone 
vontains cavities and only differs from the 
spongy portion in the fact that these 


ca are much sinaller and the hard true bony 


plates surrounding them much more nu- 
merous in proportion than in the spongy 
section of the shaft of the hu- 





merus be examined (Fig. 38) with a microscope magnifying 





HISTOLOGY OF BONE. 89 


twenty diamoters, it will be seen that numerous openings 
exist all over the compact parts of the section and gradu- 
ally become larger as this passes into the cancellated part, 
next the medullary cavity. These openings are the cross- 
sections of tubes known as the Haversian canals, which 
ramify all through the bone, running mainly in the direc- 


Fig, —A, @ tranverse section of the ulna, natural sia; 


showing the modul- 
lary cavity. 'B, the more deeply shaded part of « magnified twenty diamoters. 


tion of its long axis. but united by numerous cross or ob- 
lique branches as seen in the longitudiual section (Pig. 39), 
The outermost ones open on the surface of the bone be- 
neath the periosteum, and in the living bone blood-vessela 
‘run from this through the Haversian canals and convey 








90 THE HUMAN BODY. 


materials for its growth and nourishment. The average 
diameter of the Haversian canals is 0.05 mm. (¢}y of an 
inch). 

Around each Haversian canal lies a set of plates, or 
lamella, of hard bony substance (see the transverse section 
Fig. 38), each canal with its lamelle forming an Haver- 
sian system: and the whole bone is made up of a number 
of such systems, with the addition of a few lamelle lying 
in the corners between them, and a certain number which 
run around the whole bone on its outer surface. In the 
spongy parts of the bone the Haversian canals are very 
large and the intervening lamell@ few in number. 

Between the Jamell lie small cavities, the Jacuna, each 
of which is lenticular in form, somewhat like the space which 
would be inclosed by two 
watch-glasses joined by their 
edges, From the lacune many 
extremely fine branching ca- 
nals, the canaliculi, radiate 
and penetrate the bony la- 
mella in all directions. The 
innermost canaliculi of each 

7 system open into the central 
geen tab: ‘hi lepton about, 3 Haveraie eanal; and those of 
Sa various lacuna intercommu- 
nicating, these fine tubes form a set of passages through 
which liquid which has transuded from the blood-vessels 
in the Haversian canals can ooze all through the bone, 
‘The lacune and canaliculi are well seen in Fig. 39. 

Tn the living bone a granular nucleated cell lies in ench 
lacuna. These cells, or bone corpuscles, are the remnants 
of those which built up the bone, the hard parts of the lat- 
ter being really an intercellular substance or skeleton 
formed around and by these cells, much in the same way 
as a calcareous skeleton is formed around each Foraminifer 
(see Zoology) by the activity of ite protoplasm. By the 
co-operation of all the bone corpuscles, and the union of 
their skeletons, the whole bone is built up. 

In other bones we find the same general arrangement of 





COMPOSITION OF BONE. 91 


the parts, an outer dense layer and an inner spongy por- 
tion. In the flat and irregular bones there is no medullary 
cavity, and the whole centre is filled up with cancellated 
tiseue with red marrow in its spaces. For example, in 
the thin bones roofing in the skull we find an outer 
and inner hard layer of compact bone known as the ouder 
and inner tables respectively, the inner especially being very 
dense. Between the two tables lies the spongy bone, 
red in color to the naked eye from the marrow within it, 
and called the dipfoé. The interior of the vertebra: also is 
entirely occupied by spongy bone. Everywhere, except 
where a bone joins some other part of the skeleton, it is 
covered with the periosteum 

Chemical Composition of Bone. Apart from the bone 
corpuscles and the soft contents of the Haversian canals 
and of the spaces of the cancellated bone, the bony sub- 
stance proper, as found in the lamellm, is composed of 
earthy and organic portions intimately combined, so that 
the smallest distinguishable portion of bone contains both. 
The earthy matters form about two thirds of the total 
weight of a dried bone, and may be removed by soaking 
the bone in dilute hydrochloric acid. The organic portion 
left after this treatment constitutes a flexible mass, retain- 
ing perfectly the form of the original bone. By long boil- 
ing, especially under pressure at a higher temperature 
than that at which water boils when exposed freely to the 
air, the organic portion of the bone is nearly entirely con~ 
verted into gelatine which dissolves in the hot water. Much 
of the gelatine of commerce is prepared in this manner by 
boiling the bones of slaughtered animals, and even well- 
picked bones may be used to form a good thick soup if 
boiled under pressure in a Papin’s digester; much nutri- 
tious matter being, in the common modes of domestic 
cooking, thrown away in the bones. 

‘The earthy salts of bone may be obtained free from or- 
ganic matter by calcining a bone in a clear fire, which burns 
away the organic matter. The residue forms a white very 
brittle mass, retaining perfectly the shape and structural 
details of the original bone. It consista mainly of normal 








92 THE HUMAN BODY. 


calcium phosphate, or bone earth (Cas, 2POs); but there is 
also present a considerable proportion of calcium carbonate 
(CaCO,) and smaller quantities of other salts. 

Hygiene of tho Bony Skeloton. In early life the bones 
are less rigid, from the fact that the earthy matters then 
present in them bear # less proportion to the softer organic 
parts. Hence the bones of an aged person are more brittle 
and easily broken than those of a child. The bones of a 
young child are in fact tolerably flexible and will be dis- 
torted by any continued strain; therefore children shonld 
never be kept sitting for hours, in school or elsewhere, on a 
bench which is so high that the feet are not supported. If 
this be insisted upon (for no child will continue it volunta- 
rily) the thigh-bones will almost certainly be bent over the 
edge of the seat by the weight of the legs and feet, and a 
permanent distortion may be produced. For the same 
reason it is important that a child be made to sit straight in 
writing, to avoid the risk of producing a lateral curvature 
of the spinal column. ‘The facility with which the bones 
may be moulded by prolonged pressure in early life is well 
seen in the distortion of the feet of Chinese ladies, pro- 
duced by keeping them in tight shoes; and in the extraor- 
dinury forms which some races of man produce in their 
skulls, by tying boards on the heads of the children, 

Throughout the whole of life, moreover, the bones re- 
main among the most casily modified parts of the Body; 
although judging from the fact that dead bones are the 
most permanent parts of fossil animals we might be in- 
clined to think otherwise. The living bone, however, is 
constantly undergoing changes under the influence of the 
protoplasmic cells imbedded in it, and in the living Body is 
constantly being absorbed and reconstructed. The e 
rience of physicians shows that any continued pressure, 
such us that of a tumor, will cause the absorption and dis- 
appearance of bone almost quicker than that of any other 
tissue; and the same is true of any other continued pres- 
sure. Moreover, daring life the bon ‘© eminently plas- 
fie; under abnormal pressures they are found to quickly 
assume abnormal shapes, being rbed and disappearing 

















ARTICULATIONS. bs 


at points where the pressure is most powerful, and increas- 
ing at other points; tight lueing may in this way produce a 
permanent distortion of the ribs. 

When a bone is fractured a surgeon should be called in 
a8 soon as possible, for once inflammation has been set up 
and the parts have become ewollen it is much more diffi- 
cult to place the broken ends of the bone together in their 
proper position than before this has oceurred. Once the 
bones are replaced they must be held in position by splints 
or bandages, or the muscles attached to them will soon dia- 
place them again. With rest, in young and healthy per- 
song eomplete union will commonly occur in three or four 
weeks; but in old persons the process of cure is slower and 
is apt to be imperfect. 

Articulations. The bones of the skeleton are joined to- 
gether in very varions ways; sometimes so as to admit of no 
movement at all between them; in other cases so as to per~ 
mit only a limited range or variety of movement; and else- 
where so as to allow of very free movement in many direc- 
tions. All kinds of unions between bones are called articn- 
lations. 

Of articulations permitting no movements, those which 
unite the majority of the cranial bones afford a good exam- 
ple. Except the lower jaw, and certain tiny bones inside the 
temporal bone belonging to ‘the organ of hearing, all 
the skull-bones are immovably joined together. This union 
in the case of most occurs by means of toothed edges which 
fit into one another and form jagged lines of union known 
assuétres. Some of these can be well seen in Fig.26* between 
the frontal and parietal bones (coronal suture) and between 
the parietal and occipital bones (dambdoidal suture); while 
another lies along the middle line in the top of the crown 
between the two parictal bones, and is known as the sagif- 
tai suture. In new-horn children where the sagittal meets 
the coronal and Jambdoidal sutures there are largo spaces 
not yet covered in by the neighboring bones, which subse- 
quently extend over them. These openings are known as 
fontanelles. At thom a pulsation can often be felt ayn- 
chronous with each beat of the heart, which, driving more 


*P. 7 








4 THE HUMAN BODY. 





blood into the brain, distends it and causes it to push out 
the skin where bone is absent. Another good example 
ofan articulation admitting of no movement, is that between 
the rough surface on the sides of the sacram and the in- 
nominate bone. 

We find good examples of the second class of articula- 
tions—those admitting of a slight amount of movement— 
in the vertebral column. Between every pair of vertebrie 
from the second cervical to the sacrum is an elastic pad, 
the intervertebral disk, which adheres by its surfaces to the 
bodies of the vertebrm between which it lies, and only per- 
mits so much movement between them as can be brought 
about by its own compression or stretching. When the 
back-bone is enrved to the right, for instance, each of the 
intervertebral disks is compressed on its right side and 
stretched a little on its left, and this combination of move- 
ments, each individually but slight, gives considerable 
flexibility to the spinal column as a whole. 

Joints, Articulations permitting of movement by the 
gliding of one bone over another, are known as joiriés and 
wll have the same fundamental structure, although the 
amount of movement permitted in different joints is very 
different. 

Hip-Joint, We may take this as a good example of a 
true joint permitting a great amount and variety of move- 
ment. On the os innominatum is the cavity of the aveta- 
bulum (Fig. 40), which is lined inside by a thin layer of 
articular cartilage which has an extremely smooth surface. 
The bony cup is also deepened a little by a cartilaginous 
rim. The proximal end of the femur consists of a nearly 
spherical smooth head, borne on a somewhat narrower neck, 
and fitting into the acttabulam. This head also is covered 

’ with articular cartilage; and it rolls in the acetabulum like 
« ball in a socket. To keep the bones together and limit 
the amount of movement, ligaments pass from one to the 
other. ‘These are composed of white fibrous connective 
tissue (Chap. VIIL) and are extremely pliable but quite 
inextensible and very strong and tough. One is the cap- 
sular ligament, which forms a sort of loose bag all round 











SYNOVIAL JOINTS, 95 


the joint, and another is the round ligament, which passes 
from the acetabulum to the head of the femur. Should 
the latter rotate above a certain extent in its socket, the 
round ligament and one side of the capsular ligament are 
put on the stretch, and any further movement which might 
dislocate the femur (that is remove the head from its 
socket) is checked. Covering the inside of the capsular 
ligament and the ontside of the round ligament is a layer 
of flat cells, which are continued in a modified form over 


Fig, 40,—Section through the hip-Jont, 


the articular cartilages and form the synovial membrane. 
This, which thus forms the lining of the joint, is always 
moistened in health by a small quantity of glairy synovial 
fluid, something like the white of a raw egg in consis- 
tency, and playing the part of the oil with which the con- 
tignous moving surfaces in & machine are moistened; it 
makes all run smoothly with very little friction. 

Tn the natural state of the parts, the head of the femur 
and the bottom and sides of the acetabulum lie in close 
contact, the two synovial membranes rubbing together, 








96 THE HUMAN BODY, 


‘This contact is not maintained by the ligaments, which aro 
too loose and serve only to check excessive movement, 
but by the numerous stont muscles which pass from the 
thigh to the trunk and bind the two firmly together, 
Moreover, the atmospheric pressure exerted on the surface 
of the Body and transmitted through the soft parts to the 
outside of the air-tight joint helps also to keep the parts in 
contact. If all the muscles and ligaments around the 
joint be cut away it is still found in the dead Body that 
the head of the femur will be kept in its socket by this 
pressure, and so firmly as to bear the weight of the whole 
limb without dislocation, just as the pressure of the air 
will enable a boy's “sucker” to lift a tolorably heavy stone. 

Ball-and-socket Joints. Such a joint as that at the hip 
is called a ball-and-socket joint and allows of more free 
movement than anyother. ‘Through movements occurring 
in it the thigh can be flared, or bent so that the knee ap- 
proaches the chest; or extended, that is moved in the oppo- 
site direction. It can be abducted, so that the knee moves 
outwards; and addueted, or moved back towards the other 
knee again. ‘The limb can also by movements at the hip- 
joint be ciroumducted, that is made to describe a cone of 
which the base is at the foot and the apex at thehip. Fi- 
nally rofation can occur in the joint, so that with knee and 
foot joints held rigid the toes can be turned in or out, to a 
certain extent, by a rolling around of the femur in its socket. 

At the junction of the humerus with the scapula is 
another ball-and-socket joint permitting all the above 
imovements to even a greater extent. This greater range 
of motion at the shoulder-joint depends mainly on the 
shallowness of the glenoid cavity as compared with the 
acetabulum and upon the absence of any ligament answor- 
ing to the round ligament of the hip-joint. Another ball- 
and-socket joint exists between the carpus and the meta- 
carpal bone of the thamb; and others with the same variety, 
but a much leas range, of movement between each of the 
remaining metacarpal bones and the proximal phalanx of 
the finger which articulates with it. 


Hingo-Joints, Anotlier form of synovial joint is known 














FORMS OF JOINTS. 


as ahingejoint, In it the articulating bony surfaces are 
of such shape as to permit of movement, to and fro, in one 
plane only, like a door on its hinges, The joints between 
the phalanges of the fingers are good examples of hinge- 
joints. If no movement be allowed where the finger joins 
the palm of the hand it will be found that each can be 
bent and straightened at its own two joints, but not moved 
in any other way. The knee is also a hinge-joint, as is the 
articulation between the lower jaw and the base of the 
skull which allows us to open and close our mouths. The 
latter is, however, not a perfect hinge-joint, since it per- 
mits of a small amount of lateral movement such as occurs 
in chewing, and also of a gliding movement by which the 
lower jaw can be thrast forward so as to protrnde the chin 
and bring the lower row of teeth outside the upper. 

Pivot-Joints. In this form one bone rotates around an- 
other which remains stationary. We have a good example 
of it between the first and second cervical vertebra, The 
first cervical yertebra or aflas (Fig. 19*) has a very small 
body and a very large arch, and its neural canal is subdi- 
vided by a tranavorse ligament (Z, Fig. 19) into a dorsal 
and  yentral portion; in the latter the spinal cord lies. 
The second vertebra or axis (Fig. 20) has arising from its 
body the stont bony peg, D, called the odontoid process. 
This projects into the ventral portion of the space sur- 
rounded by the atlas, and, kopt in place there by the trans+ 
verse ligament, forms a pivot around which the atlas, car 
tying the skull with it, rotates when we turn the head 
from side to side. The joints on each side between the 
atlas and the skull are hinge-joints and pormit only the 
movements of nodding and raising the head. When the 
head is leaned over to one side, the cervical part of the 
spinal column is bent, . 

Another kind of pivot-joint is seen in the forearm. If 
the limb be held straight out, with the palm up and the 
elbow resting on the table, so that the shoulder-joint be 
kept steady whilo the hand is rotated until its buck is 
turned upwards, it will be found that the radius has partly 
rolled round the ulna, When the palm is upwards and 


*P. 69. 











98 THE HUMAN BODY, 


the thumb outwards, the lower end of the radius can be 
felt on the outer side of the forearm just above the wrist, 
and if this be done while the hand is turned over, it will 
be easily discerned that during the movement this end of 
the radius, carrying the hand with it, travels around the 
lower end of the ulna go as to get to its inner side. The 
relative position of the bones when the palm is upwards 
is shown at A in Fig, 41, and when the palm is down at 
B. The former position is known as supination; the lat- 
ter as pronation. The elbow 
end of the humerus (Fig. 36*) 
bears a large articular surface: 
on the inner two thirds of this, 
Tr, the ulna fits, and the ridges 
and grooves of both bones inter- 
locking form a hinge-joint, al- 
lowing only of bending or 
straightening the forearm on 
the arm. The radius, fits on 
the rounded outer third, Cpl, 
and forms therea ball-and-socket 
joint at which the movement 
takes place when the hand is 
turned from the supine to the 
prone position; the ulna forming 
a fixed bar around which the 
lower end of the radius is moved. 





a 7 1 
Gliding Joints. These per- 

viet i ganation’ mit as a rule but little move- 
2, radias; U, ulna, ment: examples are found be- 


tween the closely packed bones of the tarsus (Fig. 35+) and 
carpus, which slide a little over one another when subjected 
to pressure, 

Hygiene of the Joints. When a bone is displaced or 
dislocated the ligaments around the joint are more or less 
torn and other soft parts injured. This soon leads to in- 
flammation and ewelling which make not only the recogni- 
tion of the injury but, after diagnosis, the replacement 
of the bone, or the reduction of the dislocation, difficult. 


*P. 87. +P. 83, 





DISLOUATIONS AND SPRAINS, 99 


Moreover the muscles attached to it constantly pull on the 
displaced bone and drag it still farther out of place; so that 
it is of great importance that a dislocation be reduced as 
soon as possible. In most cases this can only be attempted 
with safety by one who knows the form of the bones, and 
possesses sufficient anatomical knowledge to recognize the 
direction of the displacement. No injury to a joint should 
be neglected. Inflammation once started there is often diffi- 
cult to check and runs on, in a chronic way, until the syno- 
vial surfaces are destroyed, and the two bones perhaps 
grow together, rendering the joint permanently stiff. A 
sprained joint should get immediate and complete rest, for 
weeks if necessary, and if there be much swelling, or con- 
tinued pain, medical advice should be obtained. An im- 
properly cared-for sprain is the cause of many a useless 
ankle or knee, 














CHAPTER VIII. 


CARTILAGE AND CONNECTIVE TISSUE. 


‘Temporary and Permanent Cartilages. In exrly life 
® great many paris of the supporting framework of the 
Body, which afterwards become bone, consist of cartilage, 
Such for example is the case with all the vertebra, and 
with the bones of the limbs. In these cartilages subse- 
quently the process known as ossification takes place, by 
which a great portion of the original cartilaginous model is 
removed and replaced by true osseous tissue. Often, how- 
ever, some of the primitive cartilage is left throughout the 
whole of life at the ends of the bones in joints where it 
forms the articular cartilages; and in various other places 
still larger masses remain, such as the costal cartilages, 
those in the external ears forming their framework, others 
finishing the skeleton of the nose which is only incom- 
pletely bony, and many in internal parts of the Body, as the 
cartilage of ‘* Adam’s apple,” which can be felt in tho front 
of the neck, and a number of rings around the windpipe 
serving to keep it open, These persistent masses are known 
na tho permanent, the others as the temporary cartilages. 
Tn old age many so-called permanent cartilages become 
ealeified—that ix, hardened and made unyielding by deposits 
of lime salts in them—withont assuming the histological 
character of bone, and this calcification of the permanent 
cartilages ig one chief cause of the want of pliability and 
suppleness of the frame in advanced life, 

Hyalino Cartilage. In its purest form cartilage is Nexi- 
ble and elastic, of a pale bluish-white color when alive and 
soon in hirge masses, and cuts readily with a knife. In thin 
pieces it is quite transparent. Everywhere except in the 





CARTILAGE. 101 


Joints it is invested by a tough adherent membrane, the 
perichondrium, which resembles in structure and function 
the periosteum of the bones. When boiled for a long time 
in water euch cartilages yield a solution of chondrin, which 
differs from gelatin in minor points but agrees with it in 
the fact that its hot watery solutions “‘ set” or golatinize on 
cooling. When a thin slice of hyaline cartilage is examined 
with a microscope it is found (Fig. 42) to consist of gran- 
ular nucleated cells, often collected into groups of two, 
four, or more, scattered through a homogeneous or faintly 
granular ground substance or matrix. Essentially, cartilage 
resembles bone, being made up of protoplasmic cells and a 
proportionately large amount of non-protoplasmic intercel- 


Fro. 42. = cartilage. .a cell with several clot and about to divide 
4, eit wien ne Sed jh, rOUP of four cells such ax would ro- 


3 repetition of the di ‘division at" 
‘and conspicuous. 


from @ repetition of th ‘of tho matrix are 


lular substance, the cells being the more actively living 
part and the matrix their product. Examples of this hya- 
line variety (so called from its glassy transparent appear- 
anee) are found in all the temporary cartilages, and in the 
costal and articular among the permanent. 

They rarely contain blood-vessels except at those points 
whore a temporary cartilage is being removed and replaced 
by bone; then blood-vessels run in from the perichondrium 
and form loops in the matrix, around which it is absorbed 
and bony tissue deposited. In consequence of the usual 
absence of blood-vessels the nutritive processes and ex- 
changes of material must he small and slow in cartilage, as 








102 THE HUMAN BODY. 


might indeed be expected from the passive and merely 
mechanical réle which this tissue plays. 

Hyaline cartilage is the type, or most characteristically 
developed form, of a tissue found with modifiedtions else- 
where in the Body. One of its other modifications is the 
so-called cellular cartilage, which consists of the cells with 
hardly any matrix, only just enough to form a thin capsule 
around each. This form is that with which all the car- 
tilages commence, the hyaline variety being built up by the 
increase of the cell capsules and their fusion to form the 
matrix. It persists throughout life in the thin cartilaginous 
plate of a mouse’s external ear. Other varieties of cartilage 
are really mixtures of true cartilage and connective tissues, 
and will be considered after the latter. 

The Connective Tissues. ‘These complete theskeleton, 
marked out in its coarser features by the bones and car- 
tilages, and constitute the final group of the supporting 
tissues. They occur in all forms from broad membranes 
and stout cords to the finest threads, forming networks 
around the other ultimate histological elements of various 
organs. In addition to subsidiary forms, three main varie- 
ties of this tissue are readily distinguishable, viz., areolar, 
white fibrous, and yellow elastic. Each consists of fibres 
and cells, the fibres being of two kinds, mixed in nearly 
equal proportions in the areolar variety, while ono kind 
predominates in one and another in the second of the re- 
maining chief forms. 

Aroolar Connective Tissuo, This exists abundantly be- 
neath the skin, where it forms a loose flocculent layer, 
somewhat like raw cotton in appearance but not so white. 
It is on acconnt of its loose texture that the skin can every- 
where be moved, more or less, to and fro over the subja- 
cont parts to which it is united hy this tissue. Areolar 
tissue consists of innumerable bands and cords interlacing 
inall directions, and can be greatly distended by blowing air 
in at any point, from whence it travels widely through the 
intercommunicating meshes. In dropsy of the legs or feet 
the cavities of this tissue are distended with lymph. From 
beneath the skin the areolar tissue extends all through the 








OONNECTIVE TISSUES. 


Body between the muscles and around the blood-vessels and 
auerves; and still finer layers of it enter into these and other 
organs and unite their varions parts together. It consti- 
tates in fact a soft packing material which fills up the 
holes and corners of the Body, as for instance around the 
blood-vessels aud between the muscles in Fig. 4. 

Microscopic Structure of Areolar Tissue, When exam- 
ined with the microscope areolur tissue is seen to consist of 
nucleated cells imbedded in a ground substance which is 
permeated by fibres. The fibres everywhere form the pre- 
dominant feature of the tissue (the homogencous matrix 
and the cells being inconspicuous) and are of two very dif- 
ferent kinds. In a strict sense indeed the areolar tissue 
ought to be considered as a mixture of two tissues, one 
corresponding to each variety of fibres in it. It is charac- 
terized as a distinct individual by its loose texture and by 
the fact that the two forms of fibres are present in tolera- 
bly equal quantities. In many places a tissue containing 
the same histological elements as the areolar tissue is found 
in the form of dense membranes, as for example periosteum 
and perichondrium. 

White Fibrous Tissue. One of the vavicties of fibres 
pervading the matrix of areolar tissue exists almost un- 
mixed with the other kind in the cords or tendons which 
unite muscles to the bones. This form, known as (he white 
fibrous connective tissue, also exists fairly puro in the 
ligaments around most joints. Physically it is very flexi- 
ble but oxtremely tough and inextensible, so that it will 
readily bend in any direction but is very hard to break; 
whon frosh it has an opaque white color. 

White fibrous tissue (Fig. 43) consists of a matrix, con- 
taining cavities in which cells lic and pervaded by bundles 
of extremely fine fibres. These fibres lie in each bundle 
tolerably parallel to one another in a wavy course (Fig. 43) 
and never branch or unite. Their diameter varies from 
0.0005 to 0.001 millimeter (¢5355 to xyhye of an inch). 

Chemically this tissue is characterized by the fact that 
ita fibres swell up and become indistinguishable when 
treated with dilute acetic acid, and by tho fact that it 








Ws THE HUMAN BODY. 


yields in when boiled in water. The substance in it, 
and inthe bones, which is turned into gelatin by such 
treatment is known as collagen. Glue ix impure gelatin 
obtained from tendons and ligaments, and calf’s-foot 
jelly, s0 often recommended to invalids, is a purer form of 
the sume substance obtained by boiling the feet of calves, 
which contain the tendons of many muscles passing from 
the log to the foot, 





48.-White ftyrous connective tiene, highly magnified. The nucleated 
Jon, goon elcowse and appearing spindle-shaped, are seen herd and 
‘on the surface of the bundles of Blew, 
4, da Vellow elastic tise, magnified after ite bres have been torn 
apart 








Blastio Tissue. This is almost invariably mixed in some 
proportion in all specimens of white fibrous tissue, even 
tho purest, such as the tendons of muscles; but in certain 
placos it exists almost alone, as for example in the liga- 
ments (ligamenta sudjlave) between the arches of the 
vertobrw, and in the coats of the larger arteries. In quad- 
rupods it forms the great ligament already referred to (p. 
$4), which holps to sustain the head. This tissue, in 











CONNECTIVE-TISSUE CORPUSCLES. 105 


mass, is of a dull yellow color and extremely extensible and 
elastic; when purest nearly as much so as a piece of india- 
rabber, Sometimes it appears under the microscope to be 
made up of delicate membranes, but most often it is in the 
form of fibres (Fig. 43a) which are coarser than those of 
white fibrous tissue and frequently branch and unite. It 
is unaffected by acetic acid and does not yield gelatin when 
boiled. 

Connective-Tissue Corpuscles. The fibres of white fi- 
brons tissue, wherever it is found, are united into bundles 
by astructureless ground material known as the cement sub- 
stance, which also invests cach bundle, or skein as we may 
call it, with a delicate coating. In this ground sub- 
stance are numerous cavities, branched and flattened in 


Fis. 44.—Connective-tissue corpuscles, 


one diameter, and often intercommunicating by their 
branches. In these cavities lie nucleated masses of proto- 
plasm (Fig. 44), frequontly also branched, known as the 
connective-tissue corpuscles, These it is which build up 
the tissue, each cell in the course of development forming 
around it a quantity of intercellular substance, which sub- 
sequently becomes fibrillated in great part, the remainder 
forming the cement. The cells do not quite fill the cavi- 
ties in which they lie, and these opening into others by 
their offsets there is formed a set of minute tubes ramify- 
ing through the connective tissues; and (since these in 
turn permeate nearly all the Body) pervading all the organs. 
In these cell cavities and their branches the lymph flows 
before it enters definite lymphatic vessels, and they are ac~ 








106 THE HUMAN BODY, 


cordingly known as lymph canaliculi. In addition to the 
fixed branched connective-tissue corpuscles lying in the eavi- 
ties of the ground-substance there are often found other 
cells, when living connective tissue is examined by the micro- 
scope. These cells much resemble white blood corpuscles, 
and probably are such which have bored through the walls 
of the finer blood-vessels, They creep about along the 
canaliculi by means of their faculty of amaboid movement, 
and are known as the “wandering cells.” During in- 
flammation at any point their number in that region is 
greatly increased. 

Subsidiary Varicties of Connective Tissue. In various 
parts of the Body are connective-tissue structures which 
have not undergone the typical development, but have de- 
parted from it in one way or another. The cells having 
formed « non-fibrillated intercellular substance around 
them, development may go no farther and the mass remain 
permanently as the jelly-like connective tissue; or, as in 
the vitreous humor of the eye (Chap. XXXL), the cells 
having formed the soft matrix, may disappear and leave the 
latter only. In other cases the intercellular substance 
disappears and the cells branching, and joining by the ends 
of their branches, form a network themselves, nucleated or 
not at the points answering to the centre of each originally 
separate cell. This adenoid connective tissue is found 
widely distributed in the Body especially in connection 
with the lymphatic system, and forming a supporting 
framework for the propor nervous elements in the brain 
and spinal cord. In other cases the cells almost alone con- 
stitute the tissue, becoming flattened, closely fitted at their 
edges, and united by a very small amount of cement sub- 
stance, Membranes formed in this way lie beneath layers 
of epithelium in many places and are known as basement 
membranes, and the flattened cells which line jomts and the 
serons cavities seem really to be closely apposed flattened 
connective-tissue corpuscles. 

Elastic Cartilage, and Fibro-Cartilage. We may now 
return to cartilages and consider those forms which are 
made up of more or less true cartilage mixed with more or 





INTERARTICULAR OARTILAGES. 107 


Jess connective tissue of one kind or another. ‘The carti- 
Jages of the ear and nose and some others have their matrix 

by fine branching fibres of yellow clastic tissue, 
which form networks around the groups of cartilage cells, 
Such cartilages are pliable and tough and possess also con- 
siderable extensibility and elasticity. ‘They are known as 
elastic or, from their color, us yellow cartilages. Elsewhere, 
especially in the cartilages which lie between the bones in 
some joints, we find forms which have the matrix pervaded 
hy white fibrous tissue and known as fidro-cartilages. Tor 
example the articular cartilage on the end of the lower jaw 


Fin, 42.-Section through the Joint of the lower Jaw showing ita interartioular 


Bee vcaninge wih Lie ayucnial wavity on cock andserie 


does not come into direct contact with that coveringits socket. 
on the skull, but lying between the two in the joint (Fig. 45) 
is an inferarticular jibro-cartilage : jar cartilages exist 
in the knee-joint; and the intervertebral disks are also made 
up of this tisuc. Both elastic cartilage and fibro-cartilago 
offen shade off insensibly into pure elastic or pure white 
fibrous connective tissue, 

of the Supporting Tissues. Bone, cartilage, 
snd connective tissne all agree in broad structural charac- 
ters, and in the uses to which they are applied in the Body, 
In each of them the cells which have built up the tissue, 








108 THE HUMAN BODY. 


with rare exceptions, form an inconspicuous part of it in 
its fully developed state, the chief mass of at consisting 
of intercellular substance. In hyaline cartilages this latter 
is not fibrillated; but these cartilages pass insensibly in va- 
rious regions of the Body into elastic or fibro-cartilages, and 
these latter in turn into elastic or fibrous connective tissue. 
The lamella of bone, too, when peeled off a bone softened 
in acid and examined with a very high magnifying power, 
are seen to be pervaded by fine fibres. Structurally, there- 
fore, one van draw no hard and fast line between these tis- 
sues, The same ig true of their chemical composition; bone 
and white fibrous tissue contain a substance (collagen) 
which is converted into gelatin when boiled in water; and 
in old people many cartilages become hardened by the de- 
posit in their matrix of the same lime salts which give its 
hardness to bone. Further, the developmental history of 
all of them is much alike. In very early life each is repre- 
sented by cells only : these form an intermediate substance, 
and this subsequently may become fibrillated, or calcified. 
or both. Finally they all agree in manifesting in health no 
great, physiological activity, their use in the Body depend- 
ing upon the mechanical properties of their intercellular 
substance. 

‘The close alliance of all three is further shown by the 
frequency with which they replace one another. All the 
bones and cartilages of the adult are at first represented 
only by collections of connective tissue. Before or after 
birth this is in some cases substituted by bone directly (as 
in tho case of the collar-bone and the bones on the roof of 
the skull), while in other cases cartilage sapplants the con- 
nective tissue, to be afterwards in many places replaced by 
bone, while elsewhere it remains throughout life. 

Moreover in different adult animals we often find the 
same part bony in one, cartilaginous in a second, and com- 
posed of connective tissue in a third: so thut these tissues 
not only represent one another at different stages in the 
life of the sume animal but permanently throughout the 
whole life of different animals. Low in the animal scale 





HYGIENE OF GROWING SKELETON. 109 


‘we find them all represented merely by cells with strac- 
tureless intercellular substance: a little higher in the scale 
the latter becomes fibrillated and forms distinct connective 
tissue. Inthe highest Mollusks (see Zoology), as the cuttle- 
fishes, this is partly replaced by cartilage, and the same 
is true of the lowest fishes; while in some other fishes and 
the remaining Vertebrates, we find more or less bone ap- 
pearing in place of the original connective tissue or carti- 
I 


From the similarity of their modes of development and 
fundamental structure, the transitional forms which exist 
between them, and the frequency with which they replace 
one another, histologists class all three (bone, cartilage, and 
connective tissue) together as homologous tissues and re- 
gard them as differentiations of the same original strue- 
ture, 


‘Hygienic Remarks. Since in the new-born infant many 
parts which will ultimately become bone, consist only of car- 
tilage, the young child requires food which shall contain a 
large proportion of the lime salts which are used in building 
np bone. Nature provides this in the milk, which is rich in 
such salts (see Chap, XX. ), and no other food can thoroughly 
replace it. If the mother’s health be such as to render it 
unwise for her to nurse her infant, the best substitute, 
apart from a wet-nurse, will be cow's milk diluted with one 
fourth its volume of water. Arrowroot, corn-flour, and 
other starchy foods will not do alone, since they are all defi- 
cient in the required salts, and many infants | though given 
food abundant in quantity are really starved, sinco their food 
does not contain the substances requisite for their healthy 
development. 

At birth even those bones of a child which are most ozsi- 
fied are often not continuous masses of osscous tissue. In 
the humerus for example the shaft of the bone is well 
ossified and so is each end, but between the shafts and each 
of the articular extremities there still remains a cartilagi- 
nons layer, and at those points the bone increases in length, 
new cartilage being formed and replaced by it, The bone 








10 THE HUMAN BODY. " 


increases in thickness by new osseous tissue formed beneath 
the periosteum, ‘The same thing is true of the bones of the 
leg. On account of the largely cartilaginous and imperfectly 
knit state of its bones, it is cruel to encourage a young child 
to walk beyond its strength, and may lead to “ bow-legs” 
or other permanent distortions. Nevertheless here as else 
where in the animal body, moderate exercise promotes the 
growth of the tissues concerned, and it is nearly as bad to 
wheel a child about forever in a baby-carriage as to force 
it to walk beyond its strength. 

‘The best rae is to let a healthy child use ita limbs when 
it feels inclined, but not by praise or blame to incite it to 
efforts which are beyond its age, and so sacrifice its healthy 
growth to the vanity of parent or nurse. 

The final knitting together of the bony articular ends 
with the shaft of many bones takes place only compara- 
tively lute in life, and the age at which it oceurs varies 
much in differont bones, Generally speaking, a layer of 
cartilage remains between the shaft and the ends of the 
bone, until the latter has attained its fulladult length. ‘Do 
take a few examples: the lower articular extremity of the 
humerus only becomes continuous with the shaft by bony 
tissue in the sixteenth or seventeenth year of life. The 
upper articular extremity only joins the shaft by bony con- 
tinuity in the twentieth year. The upper end of the femur 
joins the shaft by bone from the seventeenth to the nine- 
teenth year, and the lower end during the twentieth. In 
the tibia the upper extremity and the shaft unite in the 
twenty-first your, and the lower end and the shaft in the 
eighteenth or nineteenth: while in the fibula the upper end 
joins the shaft in the twenty-fourth year, and the lower 
end in the twenty-first. The separate vertebre of the 
serum are only united to form one bone in the twenty-fifth 
yeur of life; and the iliam, ischium, and pubis unite to 
form the os innominafem about the sume period. Up to 
about twenty-five then the skeleton is not firmly “ knit,” 
and is incapable, without risk of injury, of bearing strains 
which it might afterwards meet with impunity. To let 





FAT-ORLLS, M1 


Inds of sixteen or seventeen row and take other exercise in 
plenty is one thing, and a good one; but to allow them to 
undergo the severe and prolonged strain of training for 
and rowing a race is quite another, and not devoid of 
risk. 

Adiposo Tissue. Fatty substances of several kinds ex- 
ist in considerable quantity in the human Body in health, 
some as minute droplets floating in the bodily liquids or 
imbedded in various cells, but most in special cells, nearly 
filled with fat, and collected into masses with supporting 
and nutritive parts, to form adipose tissue. In fact al- 
most in every spot where the widely distributed areo- 
lar tissue is found, there is adipose tissue in greater or 
Jess proportion along with it. Considerable quantities ex- 
ist for example in the subcutaneous areolar tissue, espe- 
cially in the fomale sex, giving the figure of the woman its 
general graceful roundness of contour when compared with 
that of the male. Large quantities commonly lie in the 
abdominal cavity around the kidneys; in the eye-sockets, 
forming a pad for the eyeballs; in 
the marrow of bones; around the 
joints, aud #0 on. 

Examined with the microscope 
(Fig. 46) adipose tissue is found to 
consist of small vesicles from 0.2 
mm. to 0.09 mm. (;}y to x4e inch) 
in diameter, clustered together into 
Tittle masses and bound tooneanother 
by connective tissue and blood-ves- yg sg Frat colle with 
sols which intertwine around them; supporting connective “Us 
in this way the little angular masses 
which are seen in beef suet are formed, each mass be- 
ing separated by a somewhat coarser partition of areo- 
lar from its neighbora The individual fat-cells are 
round or oval except when closely packed, when they 
become polygonal. Each consists of a delicate enye- 
lope containing oily matter, which in life is liquid 
at the temperature of the Body. Besides the oily mat- 
ter, a nucleus is commonly present in each fat-cell: 








and sometimes # thin layer of protoplasm forms a lin- 
ing to the cell-wall. ‘The oily matter consists of a mixture 
of palmatin, olein and stearin, which are compounds of 
palmitic, stearic and oleic acids with glycerine, three 
molecules of the acid being combined with one of glycerine, 
with the elimination of water; as for example: 


3 (Culln® | 0) + Of 0: = 8(OuHin®) t Or 4-8 H0, 
‘Stearic acid, Glycerine, ‘Stearin, ‘Water. 





CHAPTER IX. 
THE STRUCTURE OF THE MOTOR ORGANS. 


Motion in Animals and Plants. If one were asked to 
point out the most distinctive property of living animals,the 
answer would probably be, their power of executing spontane- 
ons movements. Animals as we commonly know them are 
rarely at rest, while trees and stones move only when acted 
upon by external forces, which are in most cases readily re~ 

Even at their quietest times some kind of mo- 
tion is observable in the higher animals. In ourown Bod- 
jes during the deepest sleep the breathing movements and 
the beat of the heart continue; their cessation is to an on- 
looker most obvious sign of death. Here however, as else- 
where in Biology, we find that precise boundaries do not 
exist; at any rate so far as animals and plants are concerned 
we cannot draw a hard and fast line between them with 
reference to the presence or absence of apparently sponta- 
neons motility. Many a flower closes in the evening to ex- 
pand again in the morning sun; and in many plants compara- 
tively rapid and extensive movements can be called forth by a 
slight touch, which in itself is quite insufficient to produce 
mechanically that amount of motion in the mass. The 
Venus’s flytrap (Dionwea muscipula) for example has fine 
hairs on its leaves, and when these are touched by an insect 
the leaf closes up so as to imprison the animal, which is 
subsequently digested and absorbed by the leaf. The higher 
plants it is true have not the power of locomotion, they 
cannot change their place as the higher animals can; but 
on the other hand some of the lower animals are perma- 
nently fixed to one spot; and among the lowest plants many 
are known which swim about uctively through the water in 








114 THE HUMAN BODY. 


which they live. The lowest animals and plants are in fact 
those which have undergone least differentiation in their 
development, and which therefore resemble each other in 
possessing, in a more or less manifest degree, all the fanda- 
mental physiological properties of that simple mass of pro- 
toplasm which formed the starting point of each individual. 
With the physiological division of labor which takes place 
in the higher forms we find that, speaking broadly, plants 
especially develop nutritive tissues, while animals are char- 
acterized by the high development of tissues with motor 
and irritable properties; so that the preponderance of these 
latter is very marked when a complex animal, like a dog 
or & man, is compared with a complex plant, like a pine 
ora hickory. The higher animal possesses in addition to 
greatly developed nutritive tissues (which differ only in 
detail from those of the plant, and constitute what are 
therefore often called oryans of vegetative life), well-devel- 
oped spontaneous, irritable and contractile tissues, found 
mainly in the nervous and muscular systems, and forming 
what have been called the organs of animal life. Sinoe 
these place the animal in close relationship with the sur- 
rounding universe, enabling slight external forees to excite 
it, and it in turn to act upon external objects, they are also 
often spoken of as organs of relation. In man they haye a 
higher development on the whole than in any other animal, 
and give him his leading place in the animate world, and 
his power of so largely controlling and directing natural 
forces for his own good, while the plant can only passively 
strive to endure and make the best of what happens to 
it; it has little or no influence in controlling the hap- 
pening. 

Amoboid Cells. The simplest motor tissues in the adult 
Human Body are the amoboid cells (Fig. 12) already de- 
scribed, which may be regarded as the slightly modified 
descendants of the undifferentiated cells which at one 
time made up the whole Body. In the adult they are not 
attached to other parts, so that their changes of form only 
affect themselves and produce no movements in tho rest of 
the Body. Hence with regard to the whole frame they 








OTELIATED CELLS. 5 


can hardly be called motor tissues, and so are placed in a 
group by themselves under the name of undifferentiated 
tissues. 

Ciliated Collis. As the growing Body develops from its 
primitive simplicity we find that the cells lining some of 
the tubes and cavities in its interior undergo a very re- 
markablechange, by which each cell differentiates itself into 
a nutritive, and a highly motile and spontaneous portion. 
Such cells are found for example lining the windpipe, and 
a number are represented in Fig. 47. Each has a conical 
form, the base of the cone being turned to the cavity of 
the air-tube, and contains an oval nucleus, witha nucleolus. 
On the broader free end are a number (about thirty on the 
average) of extremely fine processes called cilia. During 
life these are in constant rapid move- 


ment, lashing to and fro in the liquid 
which moistens the interior of-the 
passage; and as the cells are very 
closely packed, a bit of the inner sur- 


face of the windpipe examined with 
amicroscope, looks like a field of wheat 
or barley when the wind blows over 
it. Each cilium strikes with more 
foreo in one direction than in the opposite, and as this di- 
rection of more powerful stroke is the same for all the cilia 
on any one surface, the general result is that the liquid in 
which they move is driven one way. In the case of the 
windpipe for example it is driven up towards the throat, 
and the tenacious liquid or mucus which is thus swept 
along is finally coughed or ‘“hawked” up and got. rid of, 
instead of accumulating in the deeper air-passuges away 
down in the chest. 

‘These cells afford au extremely interesting example of the 
division of physiological employments. Each proceeds from 
acell which was primitively equally motile, automatic, and 
nutritive in all its parts. But in the fully developed state 
the nutritive duties have been especially assumed by the 
conical cell-body, while the automatic and contractile prop- 
erties have been condensed, so to speak, in that modified 


Fro. 47.—Ciliated cells, 








16 THE HUMAN BODY, 


portion of the primitive protoplasmic mass, which forms the 
cilia. These, being supplied with food by the rest of the 
cell, are raised ubove the vulgar cares of life and have the 
opportunity to devote their whole attention to the perform- 
ance of automatic movements; which are accordingly far 
more rapid and precise than those executed by the whole 
vell before any division of labor had occurred in it. 

‘That the movements depend upon the structure and com- 
position of the cells themselves, and not upon influences 
reaching them from the nervous or other tissues, is proved 
by the fact that they continue for a long time in isolated 
cells, removed and placed in a liquid, as blood serum, which 
does not alter their physical constitution. In cold-blooded 
animals, as turtles, whose constituent tissues frequently 
retain their individual vitality long after that bond of union 
has been destroyed which constitutes the life of the whole 
animal as distinct from the lives of its different tissues, the 
ciliated cells in the windpipe haye been found still at work 
three weeks after the general death of the animal. 

The Muscles. These are the main motor organs ; their 
general appearance is well known to every one in the lean 
of butcher’s meat. While amoeboid cells can only move 
themselves, and (at least in the Human Body) ciliated 
cells the layer of liquid with which they may happen to be 
in contact, the majority of the muscles, being fixed to the 
skeleton, can, by alterations in their form, bring about 
changes in the form and position of nearly all parts of the 
Body. With the skeleton and joints, they constitute pro- 
eminently the organs of motion and locomotion, and are 
governed by the nervous system which regulates their activ- 
ity. In fact skeleton, musclos, and nervous system are 
correlated parts: the degree of usefulness of any one of 
them largely depends upon the more or less complete do- 
velopment of the others. Man’s highly endowed senses and 
his powers of reflection and reason would be of little use to 
him, were his muscles less fitted to carry out the dictates of 
his will or his joints less numerous or mobile. All the 
muscles are under the control of the norvous system, but 
all are not governed by it with the co-operation of will or 





VARIETIES OF MUSCLE. 1v 


mess; some moving without our having any direct 
knowledge of the fact. his is especially the case with cer- 
tain muscles which are not fixed to the skeleton but sur- 
round cavities or tubes in the Body, as the blood-vessels and 
the alimentary canal, and by their movements control the 
passage of substances through them. 'The former group, or 
skeletal muscles, are also from their microscopic characters 
known as striped muscles, while the latter, or visceral mus- 
cles, are called unstriped or plain muscles. Tho skeletal 
muscles being generally more or less subject to the control 
of the will (as for example those moving the limbs) are 
frequently spoken of as voluntary, and the visceral muscles, 
which change their form independently of the will, as invol- 
. The heart-muscle forms a sort of intermediate 
link ; it is not directly attached to the skeleton, but forms 
a hollow bag which drives on the blood contained in it and 
that quite involuntarily; but in its microscopic structure it 
resembles the skeletal yoluntary muscles. The muscles of 
respiration might perhaps be cited as another intermediate 
group. They are striped skeletal muscles and, as we all 
know, are to a certain extent subject to the will; any one 
can draw a deep breath when he chooses, But in ordinary 
quiet breathing we are quite unconscious of their working, 
and even when attention is turned to them the power of 
control is limited; no one can voluntarily hold his breath 
Tong enough to enffocate himself. As we shall see hereafter, 
moreover, any one or all of the striped muscles of the Body 
may be thrown into activity independently of or even 
against the will, as, to cite no other instances, is seen in the 
**fidgets” of nervousness and the irrepressible trembling of 
extreme terror; so that the names voluntary and involun- 
tary are not good ones. The functional differences be- 
tween the two groups depend really more on the nervous 
connections of each, than upon any essential difference in 
the properties of the so-called voluntary or involuntary 
muscular tissues themselves. 
‘The Skeletal Muscles. In its simplest form a skeletal 
consists of a red soft central part, called the belly, which 
tapers at cach end and there passes into one or more dense 








118 THE HUMAN BODY. 


white cords which consist nearly entirely of white fibrous 
connective tissue, These terminal cords are called the 
tendons of the muscle and serve to attach it to parts of the 
bony or cartilaginous skeleton, In Fig. 48 is shown the 
biceps muscle of the arm, which lies in front of the Aumerns. 
Its fleshy belly, 24, is seen to divide above and end there 
in two tendons, one of which, BI, is fixed to the scapula, 
while the other joins the tendon of a neighboring muscle 
(the coraco-brachial) and is also fixed above to the shoulder- 
blade. Near the elbow-joint the muscle is continued into 
a single tendon, B’, which is fixed to the radius, but gives 
an offshoot, B’, to the connective-tissue membranes lying 
around the elbow-joint. 

‘The belly of every muscle possesses the power of shorten- 
ing forcibly under certain conditions. In so doing it pulls 
upon the tendons, which being composed of inextensible 
white fibrons tissue transmit the movement to the hard 
parts to which they are attached, just as a pull at one end 
of rope may be made to act upon distant objects to which 
the other end is tied, The tendons are merely passive 
cords and are sometimes very long, as for instance in the 
case of the muscles of the fingers, the bellies of many of 
which lie away in the forearm, 

If the tendons at each end of a muscle were fixed to the 
same bone the muscle would clearly be able to produce no 
movement, unless by bending or breaking the bone; the 
probable result in such a case would be that the muscle 
would be torn by its own efforts. In the Body, however, 
the two ends of a muscle are always attached to two differ- 
ent pieces of the skeleton, between which more or less 
movement is permitted, and so when the muscle pulls it 
alters the relative positions of the parts to which its ten- 
dons are fixed. In the great majority of cases a true joint 
lies between the bones on which the muscle can pull, and 
when the latter conéracts it produces movement at the 
joint. Many muscles even pass over two joints and can 
produce movement at cither, a3 the biceps of the arm 
which, fixed at one end to the scapula and at the other to 
the-radius, can move the bones at either the shoulder or 

















120 THE HUMAN BODY. 


elbow joints. Where a muscle passes over an articulation 
it is nearly always reduced to a narrow tendon; otherwise 
the bulky bellies lying around the joints would make them 
extremely clumsy and limit their mobility. 

Origin and Insertion of Muscles. Almost invariably 
that part of the skeleton to which one end of a muscle is 
fixed is more easily moved than the part on which it pulls 
by its other tendon. The less movable attachment of a 
muscle is called its origin, the more movable its insertion, 
Taking for example the biceps of the arm, we find that 
when the belly of the muscle contracts and pulls on its 
‘upper and lower tendons, it commonly moves only the fore- 
arm, bending the elbow-joint as shown in Fig. 49, The 





310, 4.—Tho biceps muscle and the arm-bones, to illusteate how, undler ont 
nary olrcumstances, {he elbow joint is flexed when the muscle contracts 
shoulder is so much more firm that it serves as a fixed 
point, and so that end is the origin of the muscle, and the 
forearm attachment, P, the insertion. It is clear, how- 
ever, that this distinction in the mobility of the points of 
fixation of the muscle is only relative for, by changing the 
conditions, the insertion may become the stationary and 
origin the moved point; as for instance in going up a 
rope “hand over hand.” In that case the radial end of 
the muscle is fixed and the shoulder is moved through 
space by its contraction. 

Different Forms of Muscles. Many muscles of the 
Body have the simple typical form of a belly tapering to a 








FORMS OF MUSCLE. wi 
single tendon at cach end us a, Fig. 50; but others divide 


at one end and are called fwo-headed or biceps muscles; 
while some are even three-headed or triceps muscles. On 
the other hand some muscles have no tendon at all at one 
end, the belly running right up to the point of attachment; 
and some have no tendon at either end. In many muscles 
a tendon runs along one side and the fibres of the belly are 
attached obliquely to it: such muscles (4, 
Fig. 50) are called penniform or feath @ 5% 
er-like; or a tendon runs obliquely down 
the middle of the muscle and has the 
fibres of the belly fixed obliquely on 
each side of it (c, Fig. 50), forming a 
bipenniform muscle: or even two ten- 
dons may run down the belly and so form 
a tripenniform muscle. In a few cases teed aie ee 
# tendon is found in the middle of the cnet < 
belly as well as at cach end of it; such pela aaa, 
muscles are called digaséric, A muscle palnterruptelly | along 
of this form (Fig. 51) is found in con- Spiel ihe nar 
nection with the lower jaw. It arises 
by a tendon attached to the base of the skull; from there 
its first belly rans downwards and forwards to the neck by 
the side of the hyoid bone, where it ends in a tendon 
which passes through a loop serving as a pulley. This is 
succeeded by a second belly directed upwards 
towards the chin, where it ends in a tendon 
inserted into the lower jaw. Running along 
the front of the belly from the pelvis to the 
chest is a long muscle on each side of the 
a Aa a middle line called the rectus abdominis : it 
is polygastric, consisting of four bellies sep- 

arated by short tendons. Many muscles moreover are 
not rounded but form wide ‘masses, as for example 
the muscle S¢ seen on the yentral side of the shoulder-blade 
in Fig. 48. 

Gross Structure of a Muscle. However the form of 
the ekeletal muscles and the arrangement of their tendons 
may vary, the casential structure of all is 


> 








122 THE HUMAN BODY, 


consists of a proper striped muscular tissue, which is its es- 
sential part, but which is supported by connective tissue, 
nourished by blood-vessels and lymphatics, and has its ac- 
tivity governed by nerves; so that a great variety of things 
go to form the complete organ, 

A loose sheath of areolar connective tissue, culled the 
perimysinm, envelops each muscle, and from this parti- 
tions run in and subdivide the belly into bundles or fasci- 
cult which run from tendon to tendon, or for the whole 
length of the muscle when it has no tendons. The coarse- 
ness or fineness of butcher's meat depends upon the size of 
these primary fasciculi, which differs in different muscles 
of the same animal. These larger fasciculi are subdivided 
by finer connective-tissue 
membranes into smaller 
ones (as shown in Fig. 52, 
which represents a few pri- 
mary fasciculi of a muscle 
and the secondary fasciculi 
into which these are di- 
vided), euch of which con- 
sists of a certain number of 
muscular filres bound to- 
gether by very fine con- 
nective tissue and envel- 
oped in a close network of microscopic blood - vessels. 
Where a muscle tapers the fibres in the fasciculi become 
less numerous, and when a tendon is formed disappear 
altogether, leaving little but the connective tissue. 

Histology of Muscle. For the present we need only 
concern ourselves with the muscular fibres. Each of these is 
from eight to thirty-five millimeters (} to 14 inch) long, 
but only from 0.034 to 0.055 mm. (;}5 to g}y inch) in 
diameter in its widest part, and tapering to a point at each 
end. Hence in long muscles with terminal tendons, no 
fibre rans the whole length of a fasciculus, which may be a 
foot or more long, but the fasciculus is made up of many 
successive fibres, the narrow end of euch fitting in between 
the ends of those which follow it. In short or penniform 


= 








Fro, tA aad ee Bit of smu ote 


Fatural size: B. the same ‘Shoe agit 
showing the second: ay faaciall 
the prinary are composed. 











— PLAIN MUSOULAR TISSUE, 133 


‘muscles, where the fascicali are short, the fibres may run 
the whole length of each of the latter. 

Examined carefully with a good microscope each fibre 

is seen to possess a yery thin homogeneous sheath or envel- 
ope, called the sarcolemma, within which lies the contrac- 
tile portion of the fibre, 6, which presents a striped appear- 
ance as if composed of darker and dimmer alternating 
bands (Fig. 53). During life this substance is very soft or 
semiflnid, but after death it rapidly solidi- 
fies and death-stiffening, or rigor mortis, ix 
produced. Besides the contractile sub- 
stance a number of oval nuclei, each sur- 
rounded by a little unmodified protoplasm, 
lie inside the sarcolemma, The latter is 
imperforate except at one point where the 
central portion (or axis cylinder, see Chap. 
XU) of a nerve-fibre penetrates it, and 
ends in an expansion or end plate which is 
in immediate contact with the striated sub- 
stance. 

The larger blood-vessels of a muscle run 
in the coarser partitions of the connective 
tissue, and the finer ones lie close around * 
each fibre but entirely outside its sarcolem- fix 
ma. Fr 

Structure of the Unstriped Muscles. 

Of these the muscular cout of the stomach 

(Pig. 54) is a good example. They have noo 

definite tendons but form expanded mem- Sy 

branes surrounding cavities, so that they have fen 

no definite origin or insertion. Like the “** 

skeletal muscles they consist of proper contractile elements, 
with accessory connective tissue, blood-yessels, and nerves. 
‘Their fibres, however, have a very different microscopic 
structure. They present no striation but are made up of 
elongated cells (Fig. 55), bound together by a small quan- 
tity of cementing material. Each cell is flattened in one 
plane und tapers off at cach end; in ita interior lies an 
elongated nucleus with one or two nucleoli, These cells 








1% THE HUMAN BODY. 





¥io. 64.—~The muscular coat of the stomach. 


have the power of shortening in the direction of their long’ 
axis, and so of diminishing the capacity of the cavities in 
the walls of which they lic. 

Cardiac Muscular Tissue. This con- 
sists of flattened branched cells which unite 
to form a network, in the interstices of 
which blood capillaries and nerve-fibres run. 
The cells present transverse striations, but 
not so distinct as those of the skeletal mus- 
cles, and are said to haye no sarcolemma. 

The Chemistry of Muscular Tissue. ‘The 
chemical structure of the living muscular 
fibro is unknown, since all the methods of 
chemical analysis at present discovered de- 
compose and kill it. It contains 75 per 
cent of water; and, among other inorganic 
constituents, phosphates and chlorides of 
potassium, sodium, and magnesium. When 
at rest a living muscle is feebly alkaline, but 
after hard work, or when dying, this reaction 
vie ee Ttniped is reversed through the formation of sarco- 

tmuscecelis, lactic acid (O,H,0,). Muscles contain emall 
quantities of grape sugar and glycogen, and of organio 


wo 





CHEMISTRY OF MUSOLE. 125 


crystalline compounds, expecially kreatin 
TNO) Asin the caso of all other physiologically ac- 
tive tissues, however, the main post mortem constituents of 
the musenlar fibres are proteid substances, and it is proba- 
ble that like protoplasm itself (p. 24) the essential con- 
tractile part of the tissue consists of a complex body con- 
taining proteid, carbohydrate and fatty residues; and that 
during muscular work this is broken up yielding proteids, 
earbon dioxide, sarcolactic acid, with probably other 
things; for this hypothetical substance, which has never 
t been isolated, the name tnogen has been proposed. 
¢ main proteid substance obtained from muscles is that 
known as myosin, which is prepared as follows. Perfectly 
fresh and still living muscles are cut ont from a frog which 
has just been killed by destruction of its brain and spinal 
cord, a proceeding which entirely deprives the animal of 
consciousness and the power of using its muscles, but 
leaves these latter unaltered and alive for some time. The 
excised muscles are thrown into a vessel cooled below 0° C. 
by a freezing mixture and so are frozen hard before any 
great chemical change has had time to occur inthem. The 
solidified muscles are then cut up into thin slices, the bits 
thrown on a cooled filter and let grudually warm up to the 
freezing point of water, with the addition of some ice-cold 
0.5 per cent solution of common salt. Gradually a small 
quantity of a tenacious liquid filters through which is at 
first alkaline to test-paper but soon sets into a jelly and 
becomes acid. The coagulation and the aci 
the breaking up of the muscle substance into the myosin 
and other bodies referred to above. At first the jelly ia 
‘t, but soon the myosin becomes opaque and 
shrinks just like blood fibrin, squeezing out « quantity of 
muscle sertwn, and remaining itself he muscle clot. 
Myosin thus prepared is insoluble in water and in saturated 
solution of common salt, but soluble m ten per cent 
watery solutions of the latter su » When boiled it 
ysturned into coagulal roteid (p.. 


soluble, being at the same time, however, converted into 








126 THE HUMAN BODY. 


another proteid, called syntonin, which was formerly con- 
sidered to be the original proteid yielded by the muscles. 
Syntonin is insoluble in water but soluble in dilute acids 
and alkalies and its solutions are not coagulated by 
boiling. 

Beef Tea and Liebig’s Extract. From the above stated 
facts it is clear that when a muscle is boiled in water its 
myosin is cougulated and left behind in the meat: even if 
cooking be commenced by soaking in cold water, the myosin 
still remains as it is insoluble in cold water. Beef tea as 
ordinarily made, then, contains little but the flavoring 
matters and salts of the meut and some gelatin, the former 
making it deceptively taste as if it were a strong solution 
of the whole meat, whereas it contains but little of the most 
nutritious proteid portions, which in an insipid shranken 
form are left when the liquid is strained off. Various pro- 
pozals have been made with the object of avoiding this 
and getting a really nutritive beef ten; as for example 
chopping the raw meat fine and soaking it in strong brine 
for some hours to dissolve out the myosin; or extracting it 
with dilute acids which turn the myosin into ayntonin and 
dissolve it, at the same time rendering it non-coagulable by 
heat when subsequently boiled. Such methods, however, 
make unpalatable compounds which inyalids, as a rule, will 
not take. Beef tea is a slight stimulant but hardly a food 
and cannot be relied upon to keep up a pationt’sstrength for 
any length of time. Liedig’s extract of meat is essentially 
avery strong beef tea; containing much of the flavoring 
substances of the meat, nearly all its salts and the crystal- 
line nitrogenous bodies, such as kreatin, which exist in 
mnuecle, but hardly any of its really nutritive parts. From 
its stimulating effects it is often useful to persons in feeble 
health, but other food should be given with it. Tt may 
also be used on account of its flavor to add to the “ stock” 
of soup and for similar purposes; but the erroncousness of 
the common belief that it is a highly nutritious food can- 
not be too strongly insisted upon. Under the name of 
liquid extracts of meat othersubstances have been prepared 








LIQUID EXTRACT OF MEAT. 127 


by subjecting meat to chemical processes in which it un- 
dergoes changes similar to those experienced in digestion: 
the myosin is thus rendered soluble in water and uncongu- 
lable by heat, and such extracts if properly prepared are 
highly nutritious. The flavor may be improved by adding 
a little of Liebig’s extract if desired. 








CHAPTER X. 


THE PROPERTIES OF MUSCULAR TISSUE. 


Contractility. The characteristic physiological property 
of muscular tissue, and that for which it is employed in the 
Body, is the faculty possessed by its fibres of shortening 
forcibly under certain circumstances. The direction in 
which this shortening occurs is always that of the long axis 
of the fibre, in both plain and striped muscles, and it is 
accompanied by an almost equivalent thickening in other 
diameters, so that when a muscle contracts it does not 
shrivel up or diminish its bulk in any appreciable way; it 
simply changes its form. When a muscle contracts it also 
becomes harder and more rigid, especially if it has to over- 
come any resistance. This and the change of form can be 
well felt by placing the fingers of one hand over the biceps 
muscle lying in front of the humerus of the other arm. 
When the muscle is contracted so as to bend the elbow it 
can be felt to swell out and harden as it shortens. Every 
schoolboy knows that when he appeals to another to ‘feel 
his muscle” he contracts the latter so as to make it thicker 
and apparently more massive as well as harder. In statues 
the prominences on the surface, indicating the muscles be- 
neath the skin, are made very conspicuous when violent 
effort is represented, so as to indicate that they are in vigor- 
ous action, Ina muscular fibre we find no longer the slow, 
irregular, and indefinite changes of form seen in the undif- 
ferentiated cells of early development; this is replaced 
by a precize, rapid, and definite change of form in one di- 
rection only. Muscular tissue represents a group of cells 
in the bodily community, which have taken up the one spe- 
cial duty of executing changes of form, and in proportion 





as they have fewer other things to do, they do that better. 
‘This contractility of the muscular fibres may be best con- 
ceived by considering each to possess two natural shapes; 
one, the state of rest, in which the fibres are long and nar- 
row; and the other the state of activity, in which they are 
shorter and thicker: under certain conditions the fibres 
tend to pass, with considerable force, from their resting to 
their active form, and in so doing they move parts attached 
to their tendons. When the state of activity passes off the 
fibres suffer themselves to be passively extended again by 
os force pulling ' upon them, and they so regain their rest- 
shape; and since in the living Body other parts are 
ai invariably put upon the stretch when any given 
le contracts, these by their elasticity serye to pull the 
latter back again to its primitive shape. No muscular 
fibre is known to have the power of actively expanding after 
it has contracted: in the active state it forcibly resists ex- 
tension, but once the contraction is over it suffers itself 
readily to be pulled out to its resting form. 
Irritability. With that modi i 
protoplasm of an amoeboid cell which 
cular fibre, with its great contractility, there goes » loss of 
other properties. All trace of spontaneity seems to disap- 
pear; muscles are not automatic like | 
ciliated cells; they remain at rest unless directly excited 
from without. The amount of external change required 
to excite the living muscular fibre at any mo 
ever, very small; in other words, 


contraction. In the living Hums 

or stimulus, acting upon a alma 
nervous impulse, a molecular ovement tr 
the nerve-fibres attached to it, 


acts upon the muscles, and accord 

of a part, as the face or a limb, will c: 

muscles. They may still be there, ini 

to work, but there are no means of sen 

them, and so they remain permanently Although a 








130 THE HUMAN BODY. 


nervous impulse is the natural physiological muscular 
stimulus it is not the only one known. If a muscle be 
exposed in a living animal and a slight but sudden tap be 
given to it, or a hot bar be suddenly brought near it, or an 
electric shock be sent through it, or a drop of glycerine or 
of solution of ammonia be placed on it, it will contract; so 
that in addition to the natural nervous stimulus, muscles 
ure irritable under the influence of mechanical, thermal, 
electrical,and chemical stimuli. One condition of the ef- 
ficacy of all of them is that they shall act with some sud- 
denness; a very slowly increased pressure, even if ultimately 
yery great, or a very slowly raised temperature, or a slowly 
increased electrical current passed through it, will not ex- 
cite the muscle; although far less pressure, warmth, or 
electricity, more rapidly applied would stimulate it power- 
fully. It may perhaps still be objected that it is not proved 
that any of these stimuli excite the muscular fibres, and 
that in all these cases it is possible that the muscle is only 
excited through its nerves. For the various stimuli named 
above also excite nerves (see Chap. XIII), and when we ap- 
ply them to the musele we muy really be acting first upon 
the fine nerve-endings there, and only indirectly and 
through the mediation of these upon the muscular fibres, 
‘That the muscular fibres have a proper irritability of 
their own, independently of their nerves, is, however, shown 
by the action of certain drugs—for example curari, a South 
American Indian arrow poison. When this substance is 
introduced into a wound, all the striped muscles are 
apparently poisoned, and the animal dies of suffocation 
because of the cessation of the breathing movements. But 
the poison does not really act on the muscles themselves: 
it kills the musele nerves, but leaves the muscle intact; and 
it kills the very endings of the muscle-nerves right down 
im the muscle fibres themselves. Now after its administra- 
tion we still find that the various non-physiological stimuli 
referred to above make the muscles contract just as 
powerfully as before the poisoning, so we must conclude that 
the muscles themselves are irritable in the absence of all 
nerve stimuli—or, what amounts to the same thing, when 


MUSCOLAR IRRITABILITY. 181 


all their nerve-fibres have been poisoned. The experiment 
also shows that the contractility of a muscle is a property 
helonging to itself, and that its contracting force is not 
something derived from the nerves attached to it. The 
nervestimulus simply acts like the electric shock or sudden 
blow and aronses the muscle to manifest a property which 
it already possesses, The older physiologists seeing that 
muscular paralysis followed when the nervous connection 
between a muscle and the brain was interrupted, concluded 
that the nerves gave the muscles the power of contracting. 
They believed that in the brain there was a great store of 
a mysterious thing called vital spirits, and that some of 
this was ejected from the brain along the nerve to the 
muscle, when the latter was to be set at work, and gave it 
its working power. We now know that such is not the 
ease, but that a muscle fibre is a collection of highly irrita- 
ble material which can have its equilibrium upset in a 
definite way, causing it to change its shape, under the influ- 
ence of slight disturbing forces, one of which is a ner- 
yous impulse ; and since in the Body no other kind of 
stimulus usually reaches the muscles, they remain at rest 
when their nervous connections are severed. But the 
amuseles paralyzed in this way can still, in the living Body, 
be made to contract by sending electrical shocks through 
them. Physiologically, then, muscle is a contractile ‘and 
irritable, but not automatic tissue. 

A Simple Muscular Contraction. Most of the details 
concerning the physiological properties of muscles have 
beon studied on those of cold-blooded animals. A froy’s 
muscle will retain all ita living properties for some time 
after removal from the body of the animal, and so can be 
experimented on with ease, while the muscles of a rabbit 
or cat soon dic under those circumstances. Enough has, 
however, been observed on the muscles of the higher ani- 
mals to show that in all essentials they agree with those of 
the frog or terrapin. 

When a single electric shock is sent through a muzele it 
Tapidly shortens and then, if a weight be hanging on it, 
tapidly lengthens again, The whole series of phenomena 





182 THE HUMAN BODY. 


from the moment of stimulation until the muscle regains 
its resting form is known asa *‘ simple muscular contraction” 
ora “twitch.” It occupies in the frog about one tenth of 
a second and is separable into three portions. First, there 
elaspes a time, after the stimulation and before the com- 
mencement of the shortening, which is known as the ** lost 
time” or the period of latent excitement. This lasts about 
one liundredth of a second, and represents the time during 
which molecular changes preparatory to the contraction are 
taking place in the muscle fibres, ‘Then follows the short- 
ening, at first slow, then rapid, then slower again up to a 
maximum, and occupying rather more than half of the re- 
maining time; the elongation oceupies the remainder of the 
time taken up in the contraction. In warm-blooded ani- 
mals, the duration of a simple muscular contraction is even 
less than one tenth of a second and all its stages are quick- 
ened, In any given animal, cold increases the time taken 
in a muscular contraction and also impairs the contractile 
power, as we find in our own limbs when “numbed” with 
cold. Moderate warmth on the other hand (up to near 
the point at which heat-rigor is produced) diminishes the 
duration of the contraction; so that the molecular changes 
in amuscular fibre are clearly eminently susceptible to slight 
changes in its environment. The contractility of a musele 
does not depend upon a vital force, entirely distinct from 
ordinary inanimate forces, bat upon an arrangement of its 
material elements, which is only maintained under cer- 
tain conditions and is eminently modifiable by the sur- 
roundings, 

Physiological Tetanus. It is obvious that the ordinary 
morements of the Body are not brought about by such tran- 
sient muscular contractions as those described in the last 
paragraph, Even a wink lasts longer than one tenth of a 
second. Onur movementsare, in fact, due to more prolonged 
contractions which may be described as consisting of several 
simple twitches fused together, and known as “ tetanic 
contractions”; it might be better to call them ‘compound 
contractions,” since the word tetanus has long been used 
by pathologists to signify a diseased state, such as occurs 








nine poisoning and hydrophobia, in which most of 
muscles of the Body are thrown into prolonged and 
powerful involuntary contractions. 

_ If, while a frog’s muscle is still shortening under the in- 
fluence of one electric shock, another stimulus be given it, 
‘it will contract again and the new contraction will be added 
on to that already existing, without any period of elongation 

ing between them. While the muscle is still con- 
tracting under the influence of the second stimulus a third 
electric shock will make it contract more, and so on, until 
the muscle is shortened as much as is possible to it for that 
strength of stimulus. If now the stimuli be repeated at 
the proper intervals, each new one will not produce any 
further shortening, but, each acting on the muscle before 
the effect of the lust has begun to pass off, the muscle will 
be kept in a state of permanent or * tetanic” contraction; 
and this can be maintained, by continuing the stimuli, until 
the organ begins to get exhausted or “fatigued” and it 
then commences to elongate in spite of the stimulation. 

When our muscles are stimulated in the Body, from the 
nerve-centres through the nerves, they receive from the lat- 
ter about 20 stimuli in a second, and so are thrown into 
tetanic contractions. In othe: 
most rapid movements of the’ 
exeente a simple muscular co: 
longer or a shorter tetanu: 
are executed, as in performing 
the result is obtained by r 
und alternately strengthening and weakening a little the 
tetanus of cach. 

‘Causes affecting the Bima of Museu a Contraction, 
ihe extent of shortening which ss 


asats stimulus can never cw 
much az rapidly r 
since in the latter 
simple contrictio 


0 With very power- 
fl repeated electrical stimuli a muscle can be made to 








134 THE HUMAN BODY. 


shorten to one third of its resting length, but in the Body 
the strongest effort of the will never produces a contrac- 
tion of that extent. Apart from the rate of stimulation, 
the strength of the stimulus has some influence, a greater 
stimulus causing a greater contraction, but very soon a 
point is reached after which increasing the stimulos pro- 
duces no increased contraction; the muscle has reached 
its limit. The amount of load carried by the muscle (or 
the resistance opposed to its shortening) has also an influ- 
ence, and that in a very remarkable way. Suppose we 
have u frog’s calf-muscle, carrying no weight, and find that 
with a stimulus of a certain strength it shortens two milli- 
meters (yy inch). ‘Then if we hang one gram (15.5 grains) 
on it and give it the same stimulus, it will be found to con- 
tract more, say four or five millimeters, and so on, up to 
the point when it carries eight or ten grams. After that 
an increased weight will, with the same stimulus, cause a 
less contraction. So that up to a certain limit, resistance 
to the shortening of the muscle makes it more able to 
shorten: the mere greater extension of the muscle due to 
the greater resistance opposed to its shortening, puts it into 
a state in which itis able to contract more powerfully. 
Fatigue diminishes the working power of a muscle and rest 
restores it, especially if the circulation of the blood be going 
on in it at the same time. A frog’s muscle cut out of the 
hody will, however, be considerably restored by a period of 
rest, even although no blood flows through it. 

The Measure of Muscular Work. The work done by 
a musele in a given contraction, when it lifts a weight verti- 
cally against gravity, is measured by the weight moved, mul- 
tiplied by the distance through which it is moved. In the 
above case when the muscle contracted carrying no load it 
did very little work, lifting only its own weight; when 
loaded with one gram and lifting it five millimeters it did 
five gram-millimeters of work, just as an engineer would 
say an engine had done so many kilogrammeters or foot- 
pounds, If loaded with ten grams and lifting it six 
millimeters it would do sixty gram-millimetera of work. 
Even after the weight becomes so great that it is lifted 





MUSCULAR WORK. 185 
less distance, the work done by the muscle goes 


ing, fur the bigger weight lifted more than com- 
for the leas distance through which it is raised. 
‘example, if the above muscle were loaded with fifty 
it would maybe lift that weight only 1.5 millime- 
‘ters, but it would then do seventy-five gram-millimeters 
‘of work, which is more than when it lifted ten grams six 
millimeters. A load is, however, at last reached with 
whieh the muscle does less work, the lift becoming very 
Tittle indeed, until at last the weight becomes so great that 
the muscle cannot lift it all and so docs no work when 
stimulated. Starting then from the time when the muscle 
carried no load and did no work, we pass with increasing 
weights, through phases in which it docs more and more 
work, until with one particular load it does the greatest 
amount possible to it with that stimulus: after (hat, with 
tmereasing loads leas work is done until finally a load is 
teached with which the muscle again does no work. What 
is true of one muscle i¥ of course true of all, and what ix 
‘true of work done against gravity is true of all muscular 
Work, so that there is one precize load with which a beast 
of burden or a man cin do the greatest possible amount of 
work inaday. With a lighter or heavier load the distance 
through which it can be moved will be more or less, but 
the actual work done always less. In the living Body, how- 
over, the working of the muscles depends so mach on other 
things, as the due action of tho circulatory and respiratory 
jae and the nervous energy or “ gi pon which 
stimulation of the muscles depends) of the individual 
man or beast, that the greatest amount of work obtainable 
¥s not a simple mechanical problem as it is with the excised 
muscle. é 
Influence of the Form of the Muscle on its Working 
Power, The amount of work that any muscle can do de- 
pends of course largely upon its physiological state; a 
healthy well-nourished muscle can do more than a dis- 
eased or starved one; but allowing for such variations the 
work which can be done by a muscle varies with its form. 
‘The thicker the muscles, that is the greater the number of 











136 THE HUMAN BODY 


fibres present in a section made across the long axes of the i 
fasciculi, the greater the load that can be lifted or the other 
resistance that can be overcome. On the other hand, the 
extent through which a muscle can move a weight in- 
creases with the length of its fasciculi, A muscle a foot in 
Jength can contract more than a muscle six inches long, and 
80 would move a bone throngh a greater distance, provided 
the resistance were not too great for its strength. But if 
the shorter muscle had double the thickness, then it could 
lift twice the weight that the longer muscle could. We 
find in the Body muscles constructed on both plans; some to 
have agreat range of movement, others to overcome great 
resistance, besides numerous intermediate forms which 
cannot be called either long and slender or short and thick: 
many short muscles for example are not specially thick, 
but are short merely because the parts on which they 
act lie near together. It must be borne in mind, too, that 
many apparently long muscles are really short stout ones— 
those namely in which a tendon-runs down the side or 
middle of the muscle, and has the fibres inserted obliqnely 
into it, The muscle (yastrocnemins) in the calf of the leg 
for instance (Fig. 50, 4) is really a short stout musele, for 
its working length depends on the length of its fasciculi 
and these are short and oblique, while its true cross-section 
is that at right angles to the fasciculi and is very large. The 
force with which a muscle can shorten is very great. A 
frog’s muscle of 1 square centimeter (0.39 inch) in section 
can just lift 2800 grams (98.5 ounces), anda human muscle 
of the same area more than twice as much, 

Muscular Elasticity, A clear distinction must be made 
between elasticity and contractility, Hlasticity 1s a physi- 
cal property of matter in virtue of which various bodies 
fend to assume or retain a certain shape, and when re- 
moved from it forcibly, to return to it. When a spiral 
steel spring is stretched it will, if let go, *contract” in a 
certain sense in virtue of its elasticity, but such a contrac- 
tion is clearly quite different from a muscular contraction. 
‘Lhe spring will only contract us a result of previous distor- 
tion; it cannot originate a change of form, while the mus- 


Al 


le can actively contract or change its shape when a stimulus 
sets upon it, and that without being previously stretched. 
Tk does not merely tend to return to a natural shape from 
which it has been removed, but it assumes a quite new 
natural shape, 80 that physiological contractility is a differ- 
ent thing from mere physical elasticity; the essential differ- 
ence being that the coiled spring ora stretched band 
only gives back mechanical work which has already been 
spent on it, while the muscle originates work independ- 
ently of any previous mechanical stretching. In addition 
to their contractility, however, muscles are highly elastic, 
Tf a fresh muscle be hung up and its length measured, 
and then a weight be hung upon it, it will stretch just like 
# piece of indian-rubber, and when the weight is removed, 
provided it has not been so great as to injure the muscle, 
the latter will return passively, without any stimulus or 
active contraction, to its original form. In the Body all 
the muscles are so attached that they are usually a little 
stretched beyond their natural resting length; so that when 
a limb is ampututed the muscles divided in the stump 
shrink away considerably. By this stretched state of the 
resting clastic muscles two things : ined. In the first 
place when the muscle contracts already tant, there 
is no ** slack” to be hauled in before j it pulla on the parts 
attached to its tendons: and, 
seen the working power of u 
"presence of some resistance to its 
always provided for from the first, 
insertion of the muscle so far apart as to be Sie on 
it when it begins to shorten. 

Physiology of Plain | feiss Tissue. What has hith- 
erto been said applies cially skeletal ea but 
in tho main it is true of the 
also are irritable and contractil 


Upon stimulation, al 
lapses before the 








138 THE HUMAN BODY. 


There seems in fact to be some connection between that ar- 
rangement of the contractile substance which shows itself 
under the microscope as striation and the power of rapid 
contraction, since we find that the heart, which 1s nota 
ekeletal or voluntary muscle but yet one that contracts rap- 
idly, agrees with these in having its fibres striated, 

Hygiene of the Muscles. The healthy working of the 
muzcles needs of course a healthy state of the Body gener- 
ally, 60 that they shall be supplied with proper materials 
for growth and repair and have their wastes rapidly and 
efficiently removed. In other words, good food and pure 
air are necessary for a vigorous muscular system, a fact 
which trainers recognize in insisting upon a strict dietary, 
and in supervising generally the mode of life of those who 
are to engage in athletic contests. The muscles should also 
not be exposed to any considerable continued pressure since 
this interferes with the flow of blood and lymph through 
them. 

As far as the muscles themselves are directly concerned, 
exercise is the necessary condition of their best develop- 
ment. A muscle which is permanently unused degencrates 
and is absorbed, little finally being” left but the connective 
tissne of the organ and a few muscle fibres filled with oil- 
drops. This is well scen in cuses of paralysis dependent 
on injury to the nerves.. In such cases the muscles at first 
may themselves be perfectly healthy, but lying unused for 
weeks thoy rapidly alter and,finally, when the nervous in- 
jury has been healed, the muscles ay be found incapa- 
ble of functional activity. The physician therefore is often 
careful to avoid this by exercising the paralyzed muscles 
daily by means of electrical shocks sent through the part. 
‘The same fact is illustrated by the feeble and wasted condi- 
tion of the muscles of a limb which has been kept for some 
time in splints. After the latter have been removed it 1 
only slowly, by judicions and persistent exercise, that the 
long idle muscles regain their former sizeand power. The 
great muscles of the ‘brawny arm” of the blacksmith or 
wrestler illustrate the reverse fact, the growth of the mus- 
cles by exercise. Exercise, however, must be judicious: re- 












4 MUSCULAR EXERCISE. 
continued until exhaustion it does harm; the period 
ir is not sufficient to allow replacement of the 
au work, and the muscles thus waste under too violent 
exercise as with too little. Rest should alternate with work, 
that regularly, if benetit is to be obtained. Moreover 
it exercise should never be suddenly undertaken by 
Pets nuecd to it, not only lest the muscles suffer but be- 
‘cause museular work greatly increases the work of the heart, 
not only because more blood has to be sent to the muscles 
erates, but they produce great quantities of carbon 
dioxide which must be carried off in the blood to the lungs 
for removal from the Body, and the heart must work harder 
to send the blood faster throngh the lungs and at the same 
time the breathing be bustened so as to renew the air in 
those organs faster. The least evil result of throwing too 
Yiolent work on the heart and lungs in this way, is repre- 
sented by being ‘out of breath,” which is advan 
insomuch as it may lead to a conention | of the exertion. But 
much more serious, and sometimes permanent, injuries of 
either the circulatory or respi ory organs may be caused 
by violent and prolonged efforts withont any previous train 
ing. No general rule can be laid down as to the amount 
of exercise to be taken; fora healthy man in business the 
minimum would perhaps “be represented by a daily walk of 
five miles, 

Varioties of Exercise. In walking and running the 
muscles chiefly employed are those of the lower limbs and 
trunk. ‘This is true also of rowing, which when good is 

much more by the legs than the arma: especially 
since the introduction of sliding seats. Hence any of these 
exercises alone is apt to leave the muscles of the chest and 
arms aie exercised. el no one exercise em- 


popularity. It should be that the 
legs especially need. stre 3 hile the upper limbs, in 
which delicacy of movement, as a rulo, is more desirable 
than power, do not require such constant exertion; and the 








140 THE HUMAN BODY. 


fact that gymnastic exercises are commonly carried on in- 
doors is a great drawback to their value. When the weather 
permits, out-of-door exercise is far better than that carried 
on in even the best ventilated and lighted gymnasium. 
For those who are so fortunate as to possess a garden there 
js no better exercise, at suitable seasons, than an hour's 
daily digging in it; since this calls into play nearly all the 
muscles of the Body: while of games, the modern one of, 
lawn tennis is perhaps the best from a hygienic view that 
has ever been introduced, since it not only demands great 
muscular agility in every part of the Body, but trains the 
hand to work with the eye in a way that walking, running, 
rowing and similar pursuits do not. For the same reasons 
baseball, cricket, und boxing are excellent. 

Exercise in Infancy and Childhood. Young children 
have not only to strengthen their muscles by exercise but 
also to learn to use them. Watch an infant trying to con- 
yey something to its mouth, and yon will see how little 
control it has over its muscles. On the other hand the 
healthy infant is never at rest when awake; it constantly 
throws its limbs around, grasps at all objects within its 
reach, coils itself about, and so gradually learns to exer- 
cise its powers. It is a good plan to leave every healthy 
child, more than a few months old, several times daily on 
a large bed or even on a rug or carpeted floor, with as little 
covering as is safe and that as loose as possible, and let it 
wriggle about as it pleases. In this way it will not only 
enjoy itself thoroughly, but gain strength and a knowledge 
of how to use its limbs. To keep a healthy child swathed 
ull day in tight and heavy clothes is cruelty. 

When a little later the infant commences to crawl, it is 
sufe to permit it as much as it wishes; but unwise to tempt 
it when disinclined. The bones and muscles are still foe- 
bleand may be injured by too much work. The same is 
trae of commencing walking. 

From four or five to twelve years of age almost any form 
of exercise should be permitted, or even encouraged. At 
this time, however, the epiphyses of many bones are not 
firmly united to their shafts and so anything tending to 








MUSCULAR EXEROISE. 


“throw too great a strain on the joints should be avoided. 
After that np to commencing manhood or maidenhood any 
kind of outdoor exercise for healthy persons is good, and 
girls are all the better for being allowed to join in their 
brothers’ sports. Half of the debility and general ill-health 
of so many of our women is dependent upon deficient: ex- 
orcise during childhood, and the day, which fortunately 
seems approaching, which will see dolls as unknown to, or 
‘as despised by, healthy girls as healthy boys, will see the be- 
ginning of a great improvement in the stamina of the 
female portion of our population. 

Exercise in Youth should be regulated largely by sex; 
not that women are to be shut up and made pale, delicate, 
and unfit to share the duties or participate fully in the 
pleasures of life; but the other calls on the strength of the 
adnlt woman render vigorous museular work often unad- 
visuble, especially under conditions where it is apt to br 
followed by a chill. 

A healthy boy or young man may do nearly anythin,, 
but until twenty-two or twenty-three very prolonged effort 
is unadvieable. The frame is still not firmly knit or as 
capable of endurance as it will subsequently become. 

Girls should be allowed to ride or play out-door games 
in moderation, and in any case should not be cribbed in 
tight stays or tight boots, A flannel dress and proper 
lawn-tennis shoes ure as necessary for the healthy and safe 
enjoyment of an afternoon at that game by a girl as they 
are for her brother in the base-ball field. Rowing is excel- 
lent for girls if there be any one to teach them todo it prop- 
erly, with the legs and back and not with the arms only, as 
women are so aptto row. Properly practiced it strengthens 
the back and improves the carriage. 

Exercise in Adult Life. Up to forty a man may carry 
on safely the exercises of youth, but after that sudden ef- 
forts should be avoided. A lad of twenty-one or so may, if 
trained, safely run a quarter-mile race, but to a man of 
forty-five it would be dangerous, for with the rigidity of 
the cartilages and blood-vessels which begins to show itself 
ubont that time appears a diminished power of meeting a 











12 THE HUMAN BODY. 


sudden violent demand. On the other hand the man of 
thirty would more safely than the lad of ninetcen or twenty 
undertake one of the long-distance walking mai¢hes which 
liaye lately been in vogue; the prolonged effort would be 
loss dangerous to him, though a six days’ match with its 
attendant loss of sleep cannot fail to be more or less dan- 
gerous to any one. Probably for one engaged in active 
husiness a walk of a couple of miles to it in the morning 
and back again in the afternoon is the best and most svail- 
ableexereise. ‘The habit which Americans have everywhere 
acquired, of never walking when they cun take « horse-car, 
is certainly detrimental to the general health; though the 
extremes of heat and cold to which we are subject often 
render it unavoidable. 

For women daring middle life the same rules apply: 
there should be some regular but not violent daily ex- 
ercise. 

In Old Age the needful amount of exercise is less, and it 
is still more important to avoid sudden or violent effort. 

Exercise for Invalids. This should be regulated under 
medical advice. Forfeeble persons gymnastic exercises are 
especially valuable, since from their variety they permit of 
selection according to the condition of the individual; and 
their amount can be conveniently controlled. 

Training. If any person attempts some unusual exer- 
cise he soon finds that he loses breath, gets perhaps a 
‘stitch in the side,” and feels his heart beating with un- 
wonted violence. If he perseveres he will probably faint— 
or vomit,as is frequently seen in imperfectly trained mon 
at the end of « hard boat-race, These phenomena are 
avoided by careful gradual preparation known as “ train- 
ing.” ‘The immediate cause of them lies in disturbances 
of the cirenlatory and respiratory organs, on which excessive 
work is thrown, and the further discussion of training must 
he postponed for the present, 











CHAPTER XI. 
MOTION AND LOCOMOTION. 


The Spocial Physiology of the Muscles. Having now 
considered separately the structure and properties in gen- 
eral of the skeleton, the joints,and the muscles, we may 
go on to consider how they all work together in the Body. 
The properties of « muscle for example are everywhere the 
same, but the uses of different muscles are very varied, by 
reason of the different parts with which they are connected. 
Some are muscles of respiration, others of deglutition; 
many are known as flezor's because they bend joints, others 
as exlensors.bocanse they straighten them, and soon, The 
determination of the exact use of any particular muscle is 
known as its special physiology, as distinguished from its 
general physiology, or properties as a muscle without refer- 
ence to its use as a muscle in a particular place. The uses 
of those muscles forming parts of the physiological mechan- 
isms concerned in breathing and swallowing will be studiod 
hereafter; for the present we may consider tle muscles 
which co-operate in maintaining postures of the Body; in 
producing movements of its parts with reference to one 
another; and in producing locomotion or movement of the 
whole Body with reference to its environment. 

Tn nearly all case the striped muscles carry out thoir 
functions with the co-operation of the skeleton, since nearly 
all are fixed to bones at each end and when they contract 
primarily move these, and only secondarily the soft parts 
attached to them. To this general rule there are, however, 
exceptions. The muscle for example which lifts the upper 
eyelid and opens the eye arises from bone at the back of 
the orbit, but is inserted, not into bone, but into the eyelid 


ke 








144 THE HUMAN BODY. 


directly ; and similarly other muscles arising at the back 
of the orbit are directly fixed to the eyeball in front and 
serve to rotute it on the pad of fat on which it lies. Many 
facial muscles again have no direct attachment whatever to 
bones, as for example the muscle (orbicularis oris) which 
surrounds the mouth-opening and by its contraction nar- 
rows it and purses out the lips; or the orbicularis palpe- 
brarum which similarly surrounds the eyes and when it 
contracts closes them. 

Levers in the Body. When the muscles serve to move 
bones the latter are in nearly all cases to be regarded as 
levers whose fulcra lie at the joint where the movement 
takes place. Examples of all the three forms of levers 
recognized in mechanics are found in the Human Body. 

Levers of the First Order. In this form (Fig. 56) the 
fulcrum or fixed point of support lies between the “ weight” 


P w 


wig iA lever of the firt orfer. fulcrum: P, power: W, resirtance or 
or resistance to be overcome, and the “power” or moving 
force, as shown in the diagram. The distance PF, from 
the power to the fulerum, is culled the “ power-arm;” the 
distance FW is the weight-arm. When power-arm and 
weight-arm are equal, as is the case in the beam of an ordi- 
nary pair of scales, no mechanical advantage is gained, nor 
is there any loss or gain in the distance through which the 
weight is moved. Yor every inch through which P is de- 
pressed, W will be raised an equal distance. When the 
power-arm is longer than the other, then a smaller force at 
P will raise a larger weight at W, the gain being propor- 
tionate to the difference in the lengths of the arms. For 
example if P¥ is twice as long as FW, then half a kilo- 
grom applied at P will balance a whole kilogram at W, and 


























MOTION AND LOCOMOTION. 145 


just more than half a kilogram would lift it; but for every 
centimeter through which P descended, W would only be 
lifted half a centimeter. On the other hand when the 
weight-arm in a lever is longer than the power-arm, there 
is loss in force but « gain in the distance through which 
the weight is moved. 

Examples of the first form of lever are not numerous in 
the Human Body. One is afforded in the nodding move- 
ments of the head, the fulcrum being the articulations 
between the skull and the atlas, When the chin is elevated 
the power is applied to the skull, behind the fulcrum, by 
small muscles passing from the vertebral column to the 
oecipnt; the resistance is the excess in the weight of the 
part of the head in front of the fulerum over that behind 
it, and is not great. To depress the chin as in nodding 
floes not necessarily call for any muscular effort, as the 
head will fall forward of itself if the muscles keeping it 
rect cease to work, as those of ns who have fallen asleep 
during a dull discourse on a hot day have learnt. If the chin 
however be depressed forcibly, as in the athletic feat of 
suspending one’s self by the chin, the muscles passing from 
the chest to the skull in front of the atlanto-occipital artic- 
ulation are called into play. Another example of the em- 
ployment of the first form of lever in the Body is afforded 
by the curtsey with which « lady salutes another. In 
curtseying the trunk is bent forward at the hip-joints, 
Which form the fulcrum; the weight is that of the trank 
acting as if all concentrated at its centre of gravity, which 
lies a little above the sucram and behind the hip-joints; 
and the power is afforded by muscles passing from the thighs 
to the front of the pelvis. 

Levers of the Second Order. In this form the weight 
or resistance is between the power and the fuleram. The 
power-arm /’/" is always Jonger than the weight-arm WY, 
and so a comparatively weak force can overcome a consid- 
erable resistance. But it is disadvantageous so far a8 re- 
gards rapidity and extent of movement, for it is obvious 
that when P is raised « certain distance W will be moved a less 
distance in the sume time, As an example of the employ- 

















M46 TRE HUMAN BODY. 


ment of such levers (Fig. 57) in the Body, we may take the 
act of standing on the toes. Here the foot represents the 
lever, the fulcrum is at the contact of its fore part with 


oA of the second onter. FF, tul power: W, weight. 
he nero Tndcate the direction ti which tho forces ast. ‘i 


the ground ; the weight is that of the Body acting down 
through the ankle-joints at Tu, Fig. 58; and the power is 
the great muscle of the calf acting by its tendon inserted 
into the heel-bone (Ca, Fig. 58). Another example is 
afforded by holding up the thigh when one foot is kept 
raised from the ground, as in hopping on the other. Here 
the fulcrum is at the hip-joint, the power is applied at the 





Fin. The skeleton of the foot from the outer side. Tir, su 
witch the jeg bones sriiewiate © a, tig caleannm into which Ws ertecimnde 
ARCO OF thee cate mance Ws tnaerved 5 6, Coe mactatareal bone ef the gt 


knee-cap by a great muscle (reefue femoris) inserted there 
and which arises from the pelvis: and the weight is that 
of the whole lower limb acting at its centre of gravity, 
which will lic somewhere in the thigh between the hip and 





LEVERS IN THE BODY. 


“knee joints, that is between the fulcrum and the point of 
application of the power. 
Levers of the Third Order. In these (Fig. 59) the 
pao is between the fulerum and the weight. In such 
the weight-arm is always longer than the power- 
arm, #0 the power works at a mechanical disadvantage, 
but swiftness and range of movement are gained. It is 
the lever most commonly used in the Human Body. For 
example, when the forearm is bent up towards the arm, 
the fulcrum is the elbow-joint, the power is applied at the 
insertion of the biceps muscle (Fig. 49*) into the radius 
(and of another muscle not represented in the figure, the 
brachialis anticus, into the ulna), and the weight is that 


Fro. 3—A lever of the third onder. ¥, fulorum ; P, power ; HV, weight, 


of the forearm and hand, with whatever may be contained 
in the latter, acting at the centre of gravity of the whole 
somewhere on the distal side of the point of application of 
the power. In the Body the power-arm is usually very 
short so as to guin specd und range of movement, the mus- 
cles being powerful enough to still do their work in spite 
of the mechanical disadvantage at which they are thus 
placed. The limbs are thus made much more shapely than 
would be the case were the power applied near or beyond 
the weight. 

Tt is of course only rarely that simple movements as 
those doscribed above take place. In the great majority 
of those executed several or many muscles co-operate. 

Tho Loss to the Muscles from the Direction of their 
Pull. It is worthy of note that, owing to the oblique direc- 


*P. 120, 








148 THE HUMAN BODY. 


tion in which the muscles are commonly inserted into the 
bones, much of their force is lost so far as producing move- 
ment is concerned. Suppose the log of wood in the dia- 
gram (Fig. 60) to be raised by pulling on the rope in the 
direction a; it is clear at first that the rope will act at a 
grout disadvantage; most of the pull transmitted by it will 
be exerted against the pivot on which the log hinges, and 
only a small fraction be available for elevating the latter, 
But the more the log is lifted, as for example into the 
position indicated by the dotted line, the more useful will 
be the direction of the pull, and the more of it will be spent 
on the log and the less lost unayailingly in merely increas- 
ing the pressure at the hinge. If we now consider the ac- 
tion of the biceps (Fig. 49) in flexing the elbow-joint, we 
see similarly that the straighter the joint is, the more of 





Fro. 60,—Diagram illustrating the disadvantage of an oblique pull. 


the pull of the muscle is wasted. Beginning with the arm 
straight, it works at a great disadvantage, but as the fore- 
arm is raised the conditions become more and more fayor- 
able to the musele. ‘Those who have practiced the gym- 
nastic feat of raising one’s self by bending the elbows when 
hanging by the hands from a horizontal bar, know practi- 
cally that if the elbow-joints are quite straight it is very 
hard to start; and that, on the other hand, if they are kept 
a little flexed at the beginning the effort needed is much 








POSTURES. 


‘Tess; fhe reason being of course the more advantageous 
direction of traction by the biceps in the latter case. 

‘Experiment proves that the power with which a muscle 
‘tan contract is greatest at the commencement of its short- 
ening, the very time at which, woe have just seen, it works 
at most mechanical disadvantage; in proportion as its force 
‘becomes less the conditions become more favorable to it. 
There is however, it is clear, nearly always a considerable 
toss of power in the working of the skeletal muscles, 
strength being sacrificed for variety, ease, rapidity, extent, 
and elegance of movement. 

Postures. The term posture is applied to those posi- 
tions of equilibrium of the Body which can be maintained 
for some time, such as standing, sitting, or lying, com- 
pared with leaping, running, or falling. In all postures 
the condition of stability is that the vertical line drawn 
through the centre of gravity of the Body shall fall within 
the basis of support afforded by objects with which it is in 
contact; and the security of the posture is proportionate to 
the extent of this base, for the wider it is, the less is the 
risk of the perpendicular through the centre of gravity fall- 
ing ontside of it on slight displacement. 

The Erect Posture. This is pre-eminently character- 
istic of man, his whole skeleton being modified with rofer- 
ence to it. Nevertheless the power of maintaining it is 
only slowly learnt in the first years after birth, and for 
along while it is unsafe. And though finally we learn to 
stand erect without conscious attention, the maintenance 
of that posture always requires the co-operation of many 
muscles, co-ordinated by the nervous system, The influ- 
pnee of the latter is shown by the fall which follows « 
severe blow on the head, which may nevertheless have frac: 
tured no bone and injured no mu 
the brain, as we say,“ stuns the man, and until its © 
have passed off he cannot stand upright. In standing 
with the arms straight by the sides and the feet together 
tho centre of gravity of the whole adult Body lies in the 
articulation between the sacrum and the last lumbar yerte- 
bra, and the perpendicular drawn from it will reach the 











100 THE HUMAN BODY, 


ground between the two feet, within the basis of support 
afforded by them. With the feet close together, however, 
the posture is not very stable, and in standing we com- 
monly make it more so by slightly separating them so ag to 
increase the base. The more one foot 
is in front of the other the more sway- 
ing back and forward will be compati 
ble with safety, and the greater the 
lateral distance separating them, the 
greater the lateral sway which is possi- 
ble without falling. Consequently we 
see that a man about to make great 
-moyements with the upper part of his 
Body, as in fencing or boxing, or a sol- 
dier preparing for the bayonet exercise, 
always commences by thrusting one 
foot forwards obliquely, 80 ns to increase 
his basis of support in both directions, 
‘The case with which we can stand is 
largely dependent upon the way in 
which the head is nearly balanced on 
the top of the vertebral column, so that 
but little mnscular effort is needed to 
keep it upright. In the same way the 
trunk ia almost balanced on the bip- 
joints: but not quite, its centre of gray- 
ity falling rather behind them; so that 
just as some muscular effort is needed 
to keep the head from falling forwards, 
Wo, ¢1.—Pingram s- some is needed to keep the trunk from 
lire ‘ick bask toppling backwards at the hips. Ina 
And Deion tie Sears similar manner other muscles are called 
eitivley Macy thensiee into play at other joints: as between the 
Figidand the Boayerest. vertebral column and the pelvis, and at 
the knees und ankles; and thus a certain rigidity, due to 
muscular effort, extends all along the erect Body: which 
on uccount of the flexibility of its joints could not other- 
wise be balanced on its feet as a statue can. Beginning 
(Fig. 61) at the ankle-joint, wo find it kept stiff in standing 





WALKING, WL 


by the combined and balanced contraction of the muscles 

from the heel to the thigh, and from the dorsum of 
the foot to the shin-bone (tibia). Others passing before 
and behind the knee-joint keep it from yielding; and so at 
the hip-joints: and others aguin lying in the walls of the 
abdomen and along the vertebral column, keep the latter 
rigid, and erect on the pelvis; and finally the sknll is kept 
in position by muscles passing from the sternum and yer- 
tebral column to it, in front of and behind the occipital 
condyles, 

Locomotion includes all movements of the whole Body 
in space, dependent on its own muscular efforts: such as 
eae running, leaping, and swimming. 

Tn walking the Body never entirely quits the 
een, the heel of the advanced foot touching the ground 
in each step before the toe of the rear foot leaves it. The 
advanced limb supports the Body, and the foot in the rear 
at the commencement of cach step, propels it, 

Suppose a man standing with his heels together to com- 
mence to walk, stepping out with the left foot; the whole 
Body is at first inclined forwards; the movement taking 
place mainly at the ankle-joints. By this means the cen- 
tre of gravity would be thrown in front of the base formed 
by the feet and a fall on the face result, were not simulta- 
heously the left foot slightly raised by bending the knee 
and then swung forwards, the toes just clear of the ground 
and, in good walking, the sole nearly parallel to it. When 
the step is completed the left knee is straightened and the 
sole placed on the ground, the heel touching it first and, 
the base of support thus widened from before back, 
# fall is prevented. Meanwhile the right leg is kept 
straight, but inclines forwards above with the trank when 
the latter advances, 


leaves the ground, m i he When’ the 
step of the loft le, th great | toe of the right 
alone is in contact he support. With this a push is 
given which en on over the left leg which is 
now kept rigid pt at the ankle-joint; and the right 
knee being bent that limb swings forwards, its foot just 








182 THE HUMAN BODY. 


clearing the ground as the left did before. The Body is 
meanwhile supported on the left foot alone, but when the 
right completes its step the knee of that leg is straightened 
and the foot thus placed, heel first, on the ground. Mean- 
while the left foot has been gradually leaving the ground, 
and its toes alone are at that moment upon it; from these 
a push is given, a8 before with the right foot, and the knee 
being bent so ag to raise the foot, the left leg swings for- 
wards at the hip-joint to make a fresh step. 

During each step the whole Body sways up and down 
and also from side to side, It is highest at the moment 
when the advancing trunk is vertically over the foot sup- 
porting it, and then sinks until the moment when the ad- 
vaneing foot touches the ground, when it is lowest. From 
this moment it rises as it swings forward on this foot, until 
at is vertically over it, and then sinks again until the other 
touches the ground; and soon, At the same time, as tts 
welght is alternately transferred from the right to the left 
foot and vice versa, there is a slight lateral sway, commonly 
more marked in women than in men, and which when ex- 
cessive produces an ugly “ waddling” gait. 

\ The length of each step is primarily dependent on the 
length of the legs; but can be controlled within wide lim- 
its by special muscular effort. In easy walking, little mus- 
eular work ig employed to carry the rear leg forwards after 
it has given its push. When its foot is raised from the 
ground it swings on like a pendulum; but in fast walking 
the muscles passing in front of the hip-joint, from the pel- 
vis to the limb, by their contraction foreibly carry the leg 
forwards. The easiest step, that in which there is most 
economy of labor, is that in which the limb is let swing 
freely, and since a short pendulum swings faster than a 
longer, the natural step of short-legged people is quicker 
than that of long-legged ones. 

Tn fast walking the advanced or supporting leg also 
aids in propulsion; the muscles passing in front of the 
ankle-joint contracting so as to pull the Body forwards 
over that foot and aid the pnsh from the rear foot. Hence 
the fatigue and pain in front of the shin which is felt in 





RUNNING AND LEAPING. 153 


prolonged very fast walking. From the fact that each 
foot reaches the ground heel first, but leaves it toe last, the 
length of each stride is increased by the length of the foot. 
. In,this mode of progression there is a mo- 
ment in each step when both feet are off the ground, the 
Body being unsupported inthe air. The toes alone come in 
contact with the ground in each step, and the knee-joint 
is not straight when the foot reaches the ground. When 
the rear foot is to leave the support, the knee is suddenly 
straightened, and at the same time the ankle-joint is ex- 
tended so as to push the toes forcibly on the ground and 
give the whole Body a powerful push forwards and upwards. 
immediately after this the knee is greatly flexed and the 
foot raised from the ground, and this occurs before the 
toes of the forward foot reach the latter. The swinging 
Teg in each step is violently pulled forwards and not suf- 
fered to swing naturally as in walking. By this the rapid- 
ity of the succession of steps is increased, and at the same 
tame the stride is made greater by the sort of one-legged 
Jeap that occurs through the jerk given by the straighten- 
ihg of the knee of the rear leg just before it leaves the 
ground. 

Leaping. In this mode of progression the Body is 
raised completely from the ground for a considerable 
period. In a powerful leap the ankles, knees, and hip- 
joints are all flexed as a preparatory measure, so that the 
Body w#sumes a crouching attitude. The heels, next, are 
raised from the gronnd and the Body balanced on the toes, 
The centre of gravity of the Body is then thrown forwards, 
and simultaneously the flexed joints are straightened, and 
by the resistance of the ground, the Body receives a propul- 
sion forwards; much ee the | same way a8 a ball rebounds 
from a wall. ‘The arn 


that direction; and i y 
ing either way and the arms are Kept by frase sides, 











CHAPTER XII. 
ANATOMY OF THE NERVOUS SYSTEM. 


Nerve-Trunks. In dissecting the Human Body numer- 
ous white cords are found which at first sight might be 
taken for tendons. That they are something elae however 
soon becomes clear, since a great many of them have no 
connection with muscles at all, and those which have usually 
enter somewhere into the belly of the muscle, instead of be- 
ing fixed to its ends as most tendons are, These cords are 
nerve-trunks: followed in one direction each (Fig. 62) will 
be found to break up into finer and finer branches, until 
the subdivisions become too small to be followed without 
the aid of a microscope. Traced the other way the trunk 
will in most cases be found to increase by the union of 
others with it, and ultimately to join a much larger mass 
of different structure, and from which other trunks also 
spring. ‘This mass is.a nerve-centve. ‘That end of a nerve 
attached to the centre is naturally its central, and the other 
its distal or peripheral end. Nerve-centres, then, give origin 
to nerve-trunks; these latter radiate all over the Body, 
usually branching and becoming smaller and smaller as 
they proceed from the centre; they finally become very 
small, and how they ultimately end is not in all cases cer- 
tain, but it is known that some have sense-organs at their 
terminations and others muscular fibres. The general ar- 
rangement of the Jarger nerve-trunks of the Body is shown 
in Fig. 62. Physically a nerve is not so tough or strong az 
# tendon of the same size; it may readily be split up into 
longitudinal strands, cach of which consists of a number 
of microscopic threads, the nervejibres, bound together by 
connective tissue, 





ANATOMY OF NERVOUS SYSTEM. 











Fie. #.—Dingrain iitustrating the ceneral arrangement of the merrous xystem, 
+ 





i 
= 





bi 3 


156 THE HUMAN BODY. 


Plexuses. Very frequently several neighboring nerve- 
trunks send off communicating branches to one another, 
each branch carrying fibres from one trunk to the other. 
Such networks are called plecuses (Fig. 65*),and through 
the interchanges taking place in them it often happens 
that the distal branches of a nerve-trunk contain fibres 
which it does not possess as it leaves the centre to which it 
is connected. 

Norve-Centres. The great majority of the nerves take 
their origin from the brain and spinal cord, which together 
form the great cerebro-spinal centre. Some, however, com- 
mence in rounded or oval masses which vary in size from that 
of the kernel of an almond down to microscopi¢ dimensions, 
and which are widely distributed in the Body. Each of 
these smaller scattered centres is called a ganglion, and the 
whole of them are arranged in three sets. A considerable 
number of the largest are united directly to one another by 
nerve-trunks, and also give off nerves to various orguns, 
especially to the blood-vesgels and the viscera in the thoracie 
and abdominal cavities. These ganglia and their branches 
form the sympathetic nervous system, as distinguished from 
the cerebro-spinal nervous system consisting of the brain 
and spinal cord and the nerves springing from them. Of 
the remaining ganglia some are connected with various 
cerebro-spinal tranks near their origin, while the rest, for 
the most part very small and connected with the peripheral 
branches of sympathetic or other nerves, are known as the 
sporadic ganglia. 

The Cerebro-Spinal Centre and its Membranes. Ly- 
ing in the skull is the brain and in the neural canal of the 
vertebral column the spinal cord or spinal marrow, the 
two being continuous through the foramen magnum of the 
occipital bone and forming the great cerebro-spinal nerve- 
centre. This centre is bilaterally symmetrical throughout 
except for slight differences on the surfaces of parts of the 
brain, which are often found in the higher races of mankind. 
Both brain and spinal cord are very soft and easily crushed; 
the connective tissue which pervades them being of the deli- 
cate retiform variety; accordingly both are placed in nearly 


*P. 102, 











MEMBRANES OF THE NERVE-CENTRES. WT 


completely closed bony cavities and 
are also enveloped by membranes 
which give them consistency and 
support. These membranes are 
three innumber. Externally is the 
dura mater, vory tough and strong 
and composed of white fibrous and 
elastic connective tissues. In the 
cranium this dura mater adheres 
by its outer surface to the inside of 
the skull, serving as the periosteum 
of its bones; this is not the case 
in the vertebral column, where the 
dura mater forms a loose sheath 
around the spinal cord and is only 
attached here and there to the sur- 
rounding bones, which have a sep- 
arate periosteum of theirown, The 
innermost membrane of the cerebro- 
spinal centre, lying in immediate 
contact with the proper nervous 
parts, is the pia mater, also made 
np of white fibrous tissue inter- 
woven with elastic fibres, but less 
closely than in the dura mater, so 
tts to form u less dense and tough 
membrane. The pia mater con- 
tains many blood-vessels which 
break up in it into small branches 
before entering the nervous mass 
beneath. Covering the outside of 
the pia mater is a layer of flat 
closely fitting cells, a similar layer 
lines the inside of the dura mator, 
and these two layers are described 
as the third membrane of the 
bro-spinal centre, called the arach- 
noid. In the space between the 
two layers of the arachnoid is von- 
tained a small quantity of watery 











Fup. 03.—The 


spinal cont 
aind wedufia oblongata. 
from the ventral, and #, fron 
the dorsal aspect ; © to Mf. 
ross ‘at different 
levels, 





be 








188 THE HUMAN BODY. 


cerebro-spinal liquid. Part of the surface of the brain is 
folded and the pia mater does not dip down and line the 
furrows between the folds but stretches across them: in the 
spaces thus left there is also contained someof the cerebro- 
spinal liquid. 

The Spingl Cord (Fig. 63) is nearly cylindrical in form, 
being however a little wider from side to side than dorso- 
ventrally, and tapering off at its posterior end, Its aver- 
age diameter is about 19 millimeters ($ inch) and its 
length 0.43 meter (17 inches). It weighs 42.5 grams 
(14 ounces). ‘There is no marked limit between the spinal 
cord and the brain, the one passing gradually into the 
other (Fig. 70"), but the cord is arbitrarily said to com- 
mence opposite the outer margin of the foramen magnum: 
from there it extends to the articulation between the first 
and second lumbar vertebra, where it narrows off to a 
slender filament, tho filwm terminale (cut off and repre- 
sented separately at B in Fig. 63), which rans back to the 
end of the neural canal behind the sacrum, In its course 
the cord presents two expansions, an upper, 10, the cer- 
vical enlargement, reaching from the third cervical to the 
first dorsal vertebra, and a lower or lwmdar enlargement, 
9, opposite the last dorsal vertebra. 

Running along the middle line on both the ventral and 
the dorsal aspects of the cord is a groove, and a cross-sec~ 
tion shows that these grooves are the surface indications of 
fissures which extend deeply into the cord (0, Fig. 64) and 
nearly divide it into right and left halves. 

Tho anterior fissure (1, Fig. 64) is wider and shallower 
than the posterior, 2. The transverse section, C, shows 
also that the substance of the cord is not alike throughout, 
but that its white superficial layers envelop a central gray 
substance arranged somewhat in the form of a capital H. 
Each half of the gray matter is crescent-shaped, and the 
erescents are turned back to back and united across the 
middle line by the gray commissure. The tips of cach 
crescent are called its horns or cornua, and the ventral, or 
anterior cornu, on each side is thicker and larger than the 
posterior. In the cervical and lumbar enlargements the 


*P. 169. 








SPINAL CORD. Bt 


proportion of white to gray matter is greater than else- 
where ; and as the cord approaches the medulla oblongata 
‘its central gray mass becomes irregular in form and begins 
to break up iito smaller portions. If lines be drawn on 
the transverse section of the cord from the tip of each horn 
of the gray matter to the nearest point of the eurface, the 
white substance in each half will be divided into three por- 


Fi, 61-—Thi cord , nerre- roots, A W} portion of the 
sian te seat daly mell prion ates 


tions: one between the anterior fissure and the anterior 
cornu, and called the anderior white column ; one between 
the posterior fissure and the posterior cornu, and called the 
posterior white column; while the remaining one lying ii in 
the hollow of the crescent and between the two horns is the 
lateral column. In addition to this a certain amount of 
white substance crosses the middle line at the bottom of 











160 THE HUMAN BODY. 


the anterior fissure: this forms the anterior white commis- 
steve. There is no posterior white commissure, the bottom 
of the posterior fissure being the only portion of the cord 
where the gray substance is uncovered by white. Running 
ulong the middle of the gray commissure, for the whole 
length of the cord, is a tiny channel, just visible to the 
unaided eye; it is known as the central canal (canalis cen- 
tralis). 

The Spinal Nerves, Thirty-one pairs of spinal nerve- 
trunks enter the neural canal of the vertebral column 
throngh the intervertebral foramina (p. 71). Exch di- 
vides in the foramen into a dorsal and ventral portion 
known respectively as the posterior and anterior roots of 
the nerve (6 and 5, Fig. 64), and these again subdivide into 
finer branches which are attached to the sides of the cord, 
the posterior root at the point where the posterior and late- 
ral white columns meet, and the anterior root at the junc- 
tion of the lateral and anterior columns. At the lines on 
which the roots are attached there are superficial furrows on 
the surface of the cord. On each posterior root is a spinal 
ganglion (6°, Fig, 64), placed just before it joins the an- 
terior root to make up the common nerye-trunk. Imme- 
diately after its formation by the mixture of fibres from 
both roots, the trank divides into a small posterior primary 
and a larger anterior primary branch (¥ % D, Fig. 64). 
‘The former branches of the spinal nerves go for the most 
part to the skin and muscles on the back, while the anterior 
primary branches form a series of plexuses from which the 
nerves for the sides and ventral region of the neck and 
trank, and for the limbs, arise. 

The various spinal nerves are named from the portions 
of the vertebral column through the intervertebral foramina 
of which they pass out; and aa a general rule each nerve is 
named from the vertebra in front of it. For example the 
nerve passing out between the fifth and sixth dorsal verte- 
bre is the “fifth dorsal” nerve, and that between the last 
dorsal and first lumbar yertebre, the ‘twelfth dorsal.” 
In the cervical region, however, this rule is not adhered to, 
‘The nerve passing out between the occipital bone and the 





THE SPINAL NERVES. 


atlas is culled the “ first cervical” nerve, that between the 
atlas and axis the second, and so on; that between seventh 
cervical and first dorsal yertebre being the “eighth cervi- 
eal” nerve. The thirty-one pairs of spinal nerves are then 
thus distributed: § cervical, 12 dorsal, 5 lumbar, 5 sacral, 
and Leoceygeal; the latter passing out between the sacram 
and eoceyx. Since the spinal cord ends opposite the upper 
lumbar yertebre while the sacral and coceygeal nerves pass 
out from the neural canal much farther back, it is clear 
that the roots of those nerves, on their way to unite in the 
foramina of exit and form nerve-trunks, must run obliquely 
backwards in the spinal canal for a considerable distance. 
One finds in fact the neural canal in the lumbar and sacral 
regions, behind the point where the spinal cord has tapered 
off, occupied by a great bunch of nerve-roots forming the 
so-called “ horse's tail” or cauda eguina, 

Distribution of the Spinal Nerves, It would be out 
of place here to go into detail as to the exact portions of 
the Body supplied by each spinal nerve, but the following 
general statements may be made, The anterior primary 
branches of the first four cervical nerves form on each side 
the cervical plexus (Fig. 65) from which branches are sup- 
plied to the muscles and integument of the neck: also to 
the outer ear and the back part of the scalp. The anterior 
primary branches of the remaining cervical nerves and the 
first dorsal form the brachial plerus, from which the upper 
limb is enpplied. ‘The roots of the tranks which form this 
plexus arise from the cervical enlargement of the spinal cord. 

From the fourth and fifth cervical nerves on each side, 
small branches arise and unite to make the phrenic nerve 
(4, Fig. 65) which rons down through tho chest and ends 
in the diaphragm. 

‘The anterior primary branches of the dorsal nerves, ex- 
cept part of the first which enters the brachial plexus, form 
no plexus, but each runs along the posterior border of arib 
and supplies branches to the cheat-walls, and the lower ones 
to those of the abdomen also. 

The anterior primary branches of the four anterior lam- 
bar nerves are united by branches to form the fembar 











162 THE HUMAN BODY. 


plexus. Yt supplies the lower part of the trunk, the but- 


tocks, the front of the thigh, and medial side of the leg. 
The sacral plerus is formed by the anterior primary 

branches of the fifth Inmbar and the first four sacral 

nerves, which unite into one great cord and so form the 





Fia, 65—The cervical and brachial plexuses of one sii of the Tody. 
sciatic nerve, which is the largest in the Body and, ranning 
down to the back of the thigh, ends in branches for the 
lower limb. ‘The roots of the tranks which form the sacral 
plexus arise from the lumbar enlargement of the cord. 


THE BRAIN. 163 


‘The Brain (Fig. 66) is far larger than the spinal cord 
and more complex in structure. Tt weighs on the average 
abont 1415 grams (50 ounces) in the adult male, and about 
165 grams (5.5 ounces) lessin the female, In its simpler 
forms the vertebrate brain consists of three masses, each 
with subsidiary parts, following one another in series from 
before back, and known as the fore-brain, mid-brain, and 
hind-brain respectively. In man the fore-brain, A, weighing 


c= Mlustrating the general rvlationships of the parts 
ti for brain el ra in: cerebellum 7 Ce po 


His obioagars ¢ B,C, and “B togethar eosstvuse tie hi tee ra? me 
about 1245 grams (44 ounce: 
rest put together and laps over | 
mainly of two huge convoluted “masse 
another by a deep median fissu own us the cerebral 
oe: Tht “prop ‘ize of these is 
Beneath each 
be, inconspicuous ir 
ral hemispheres, as in 
in on.each side are two 
“large gray masses, the corpora striata and optic thalami. 
The mid-brain forms a connecting isthmus between the 
two other divisions and presents on its dorsal side four 














164 THE HUMAN BODY, 


hemispherical eminences, the corpora qurdrigemina, On 
its ventral side it exhibits two semicylindrical pillars (seen 
under the nerve 7V in Fig. 70% and known as the crura 
corebri. ‘The hind-brain consists of three main parts: on 
its dorsal side is the cerebellum, #, Vig. 66, consisting of a 
right, a left,and 4 median lobe ; on the ventral side is the 
pons Varolii, C, Fig. 66, and behind the medulla oblongata, 
D, ¥ig. 66, which is continuous with the spinal cord. 

Tn nature the main divisions of the brain are not sepa- 
rated so much as has been represented in the diagram for 





Fra. (7.~'The brain from the left sidi the cerebral bern! fe 
the main bu of the fore brats COL the getebeliuray Mo the maedla’ cblom 
gata P, the pous Varolll *, the flasure of Sylviun 


the sake of clearness, but lie close together as represented 
in Fig. 67, only some folds of the membranes extending 
between them; and the mid-brain is entirely covered in on 
its dorsal aspect. Nearly everywhere the surface of the 
brain is folded, the folds, known as gyri or convolutions, 
being deeperand more numerous in the brain of man than 
in that of lower animals; and in the human species more 
marked in the higher than in the lower races. 

The brain like the spinal cord consists of gray and” 
white neryous matter but somewhut differently arranged, 
for while the brain, like the cord, contains gray matter in 


"P10. 


% 


ORREBRAL VENTRICLES. 165 


ite interior, a great part of its surface is also covered with 
it. By the external convolutions of the cerebellum and 
the cerebral hemispheres the surface over which this gray 
substance is spread is very much increased (sce Fig. 68), 
‘The Ventricles of the Brain. ‘The minute central 
canal of the spinal cord is continued into the brain and 
expands there at several points into chambers known as the 
ventricles. Bntering the medulla oblongata it approaches 
its upper surface and dilates into the fourth ventricle, 
which has a very thin roof, lapped over by the cerebellum. 
From the front of the fourth ventricle rans « narrow pas- 


Fio, &—A vertical sootion across the cerebral hemispheres, Cel? the corpus 
catioguon ; FL, tho anterior end of Che right Interal ventricle; Ube gray tass On 
Iw exterior ls Une corpus striatum, On the loft site the superficial gray matter 
covering the convolutions Is shaded. 


sage (iter a tortio ad guartum ventriculum) which enters 
another dilatation lying in the middle line near the under 
side of the fore-brain (just above the two small rounded 
masses seen between the nerves 7/ and FJ in Fig. 70) and 
known as the third ventricle. From theythird ventricle 
two apertures (the foramens of Monro) lead into the first 
and second, or lateral ventricles, one of which lies in each 











166 THE HUMAN BODY. 


of the cerebral hemispheres. The front ends of these two 
yentricles are scen in the vertical transverse section of the 
brain reyiresented in Fig. 68. 

The ventricles contain a small amount of cerebro-spinal 
liguid and are lined by epithelium which is ciliated in 
early life, 

Note, A frequent cause of apoplexy is a hemorrhage into 
one of the lateral ventricles; the outpoured blood aceu- 
mulating and pressing upon the cerebral hemispheres their 
functions are suppressed and unconsciousness produced. 
When a person is found in an apoplectic fit therefore the 
best thing to do is to leave him perfectly quiet until medi- 
cal aid is obtained: for any movement may start afresh, 
bleeding into the ventricle which had been stopped by clots 
formed in the mouths of the torn blood-vessels, . 

Sections of the Brain. Having got a general idea of 
the parts composing the brain, the best way to complete a 
knowledge of its anatomy is to study sections taken in 
various directions. Two such aro given in Figs. 68 and 69. 
Fig. 69 represents the right half of a vertical section of the 
brain, taken from before back in the middle line and viewed 
from the inner side. Above, the knife has passed between 
the two cerebral hemispheres, in the longitudinal fissure, 
without cutting either, and the convoluted inner surface of 
the right one is seen. The sickle-shaped mass lower down, 
Ce?’ to Cel’ represents the cut surface of a connecting band 
of white nervous tissue called the corpus callosum, which 
runs across the middle line from one cerebral hemisphere 
to the other and puts them in communication. Si, the 
septum lucidum, is a thin membrane which forms the inner 
wall of the lateral ventricle of the hemisphere. Between 
the two septa lucida on the sides (in the natural position 
of the parts) and the corpus callosum above is inclosed a 
narrow space known as the fifth ventricle. It is, however, 
quite different from the remaining cerebral ventricles, not 
being a continuation of the canalis centralis of the spinal 
cord. The space beneath the septum lucidum and the 
back part of the corpus callosum is the third ventricle, 
which, lying in the middle line, has been laid open in the 





MEDIAN SURFACE OF THE BRAIN. 167 


section. It is deep from above down but narrow from side 
to side. From its under side a prolongation runs down to 
H, the pituitary body ; behind, the agueduct of Sylvius, 
A, ia seon passing back from the third to the fourth ven- 
tricle, Vy. At FA is the aperture (foramen of Monro) 
leading into the right lateral ventricle. Crossing the third 
yentricle and putting the two halves of the fore-brain in 
direct communication are three emall commissures, Coa, 


ight lateral ven- 
hind ventricle, 





Com, and Cop, known respectively as the anterior, the 
median (or soft), and the posterior, The mass seen bound- 
ing a great part of the side of the third yentricle and 
united to its fellow by the soft commissure is the optic 
thalamus, Above the aqueduct is the small median body 
On, called the pineal gland, which contains no nervous * 
tissue, but has an interest as being, according to Descartes, 





168 THE HUMAN BODY. 


the seat of the soul. Behind it come the corpora quadri- 
gemina, Lq, and above the fourth ventricle the cerebellum, 
Obl, showing the primary and secondary fissures on its 
surface which give its section a branched appearance known 
us the arbor vite. Mo is the medulla oblongata, and P the 
pons Varolii. The canalis centralis of the spinal cord is 
represented leading back from the fourth ventricle. 

Fig. 68 represents a vertical transverse section of the 
brain taken through the fore part of the corpus callosum’ 
(Ccl") und altogether in front of the third ventricle. It 
shows the foldings of the cerebrum and its superficial layer 
of gray substance; the anterior ends of the lateral yentri- 
cles, Vi, with a gray mass, the corpus striatum lying be- 
neath and on the outer side of each. If the section had 
been taken a little farther back the optic thalami would 
have been found reaching the floor of cach ventricle. 

The Base of tho Brain and tho Cranial Nerves, 
‘Twelve pairs of nerves leave the skull by apertures in its 
base, and are known as the cranial nerves. Most of them 
spring from the under side of the brain, and so they are best 
studied in connection with the base of that organ, which is 
represented in Fig. 70. The first pair, or olfactory nerves, 
spring from the under sides of the olfactory lobes, J, and 
pass ont through the roof of the nose. They are the nerves 
of smell. The second pair, or optic nerves, IT, spring from 
the optic thalami and corpora quadrigemina and, under 
the name of the optic tracts, run down to the base of the 
brain where they appear passing around the crura cerebri 
4 represented in the figure. In the middle line the two 
optic tracts unite to form the optic commissure (seen in 
section at JT in Fig. 69) from which an optic nerve pro- 
ceeds to cach eyeball, Behind the optic commissure ix 
seen the conical stalk of the pifwitary body or hypophysix 
corebri (H in Fig. 69), and ‘still further back a pair of 
hemispherical masses, about the size of split peas, known as 
the corpora albicantia, 

All the remaining cranial nerves arise from the hind- 
brain. ‘The third pair (motores ocul?) arise from the front 
of the pons Varolii, and are distributed to most of the 





THE CRANIAL NERVES, 168 


muscles which move the eyeball and also to that which 
lifts the upper eyelid. The four-sided space bounded by 
the optic tracts and commissure in front and the third 
pair of nerves behind, and having on it the pituitary body 


Fra. 70. base 


~The base of 
Il tho rest, 


and the corpora albicantia, lies beneath the third ventricle, 

so that a probe pushed in there would enter that cavity. 
‘The fourth pair of nerves, JV (pathetici), arise from the 

front part of the roof of the fourth ventricle. From there, 














t 
170 THE HUMAN BODY. 


each curls around a crus cerebri (the cylindrical mass seen 
beneath it in the figure, running from the pons Varolii to 
enter the under surface of the cerebral hemispheres) and 
appears on the base of the brain. Each goes to one muscle 
of the eyeball. 

The fifth pair of nerves, V (¢rigeminales), resemble the 
spinal nerves in having two roots; one of these is much 
larger than the other and possesses a ganglion (the @asse- 
rian ganglion) like the posterior root of a spinal nerve. 
Beyond the ganglion the two roots form a common trunk 
which divides into three main branches, Of these, the 
ophthalmic 4s the smallest and is mainly distributed to the 
muscles and skin over the forehead and upper eyelid; but 
also gives branches to the mucous membrane lining the 
nose, and to the integument over it. The second division 
(superior maxillary nerve) of the trigeminal gives branches 
to the skin over the temple, to the cheek between the eye- 
brow and the angle of the mouth, and to the upper teeth; 
as well as to the mucous membrane of the nose, pharynx, 
soft palate and roof of the mouth. The third division 
(inferior maxillary) is the largest branch of the trigemi- 
nal; it receives some fibres from the larger root and all of 
the smaller. It.is distributed to the side of the head and 
the external ear, the lower lip and lower part of the face, 
the mucous membrane of the mouth and the anterior 
two thirds of the tongue, the lower teeth, the salivary 
glands, and the muscles which move the lower jaw in mas- 
tication, 

The sizth pair of cranial nerves (VJ, Fig. 70) or ad- 
ducentes arise from the posterior margin of the pons Va- 
ee and each is distributed to one muscle of the eyo- 

i 


The seventh pair (facial nerves), VII, appear also at 
the posterior margin of the pons, They are distributed 
to most of the muscles of the face and scalp. 

The eighth pair (auditory nerves) arise close to the 
facial. They are the nerves of hearing and are distributed 
entirely to the internal ear, 

The ninth pair (glossopharyngeals), IX, arising close to 





THE CRANIAL NERVES. m7 


the auditories, are distributed to the mucous membrane of 
the pharynx, the posterior part of the tongue, and the 
middle ear. 

The tenth pair (pnenmogastric nerves or vagi), X, avise 
from the sides of the medulla oblongata. Each gives 
branches to the pharynx, gullet and stomach, the larynx, 
windpipe and. lungs, and to the heart, The vagus runs 
farther through the Body than any other cranial nerve. 

The eleventh pair (spinal accessory nerves), XT, do not 
arise mainly from the brain but by a number of roots at- 
tached to the lateral columns of the cervical portion of the 
spinal cord, between the anterior and posterior roots of the 
proper cervical spinal nerves. Each, however, runs into 
the skull cavity alongside of the spinal cord and, getting a 
few filaments from the medulla oblongata, passes out along 
with the glossopharyngeal and pneumogustric nerves. Out- 
side the skull it divides into two branches, one of which 
joins the pneumogastric trunk, while the other is distrib- 
uted to muscles about the shoulder. 

The twelfth pair of cranial nerves (hypoglossi), XII, 
arise from the sides of the medulla oblongata; they are 
distributed mainly to the muscles of the tongue and the 
hyoid bone. 

Origins of the Cranial Nerves. The points re- 
ferred to above, at which the various cranial nerves appear 
on the surface of the brain, ure known as their superficial 
origins. From them the nerves can be traced for a less or 
greater way in the substance of the brain until each is fol- 
lowed to one or more masses of gray matter, which con- 
stitute its proper starting-point and are known as ils deep 
origin. The deep origins of all except the first and second 
and part of the eleventh lie in the inedulla oblongata. 

Tho Ganglia and Communications of the Cranial 
Nerves. Besides the Gasserian ganglion above referred 
to, many others are found in connection with the cranial 

us for example there ia one on each of the 

ivisions of the trigeminal, two are found on each 
pheumogastric and two in connection with the glosso- 
pharyngeal. At these ganglia and elsewhere, the various 




















1472 THE HUMAN BODY, 


nerves often receive branches from neighboring cranial or 
spinal nerves, so that very soon after it leaves the brain 
hardly any one remains free from fibres derived from other 
tranks except the olfactory, optic, and wuditory nerves, 
This often makes it difficult to say from where the nerves 
of a special part have come; for example, the nerve-fibres 
going to the submaxillary salivary gland from the trigemi- 
nal leave the brain first in the facial and only afterwards 
enter the fifth; and many of the fibres going apparently 
from the pnenmogastric to the heart come originally from 
the spinal accessory. 

The Sympathetic System. The ganglia which form 
the main centres of the sympathetic nervous system lie in 
two rows (s, Fig. 2, and sy, Fig. 3), one on either side of 
the bodies of the yertebre. Each ganglion is united by a 
nerve-trank with the one in front of it, and 80 two great 
chains are formed reaching from the base of the skull to 
the coccyx. In the trunk region these chains lie in the 
ventral cavity, their relative position in which is indicated 
by the dots sy in the diagrammatic transverse section re- 
presented on p. 7 in Fig. 3. The ganglia on these chains are 
forty-nine in number, viz., twenty-four pairs, and a single 
one in front of the coceyx in which both chains terminate. 
They are named from the regions of the vertebral column 
near which they lie; there being three cervical, twelve 
dorsal, four lumbar, and five sacral pairs. 

Bach sympathetic ganglion is united by communicating 
branches with the neighboring spinal nerves, and near the 
skull with various cranial nerves also; while from the gan- 
glia and their uniting cords arise numerous tranks, many 
of which, in the thoracic and abdominal cavities, form 
plexuses, from which in turn nerves are given off to the 
viscera. These"plexuses frequently possess numerous small 
ganglia of their own; two of the most important ure the 
cardiae plerus which lies on the dorsal side of the heart, 
and the solar plecus which lies in the abdominal cavity and 
supplies nerves to the stomach, liver, kidneys, and intes- 
tines. Many of the sympathetic nerves finally end in the 
walls of the blood-vessels of various organs. To the naked 





HISTOLOGY OF NERVES. 178 


eye they are commonly grayer in color than the cerebro- 
spinal nerves. 

The Sporadic Ganglia. These, for the most part very 
minute, nerve-centres are found scattered in nearly all 
parts of the Body. hey are especially ubundant in the 
neighborhood of secretory tissues and about blood-vessels, 
while a very important set is found in the heart. Nerves 
unite them with the cerebro-spinal and sympathetic cen- 
tres, and probably many of them belong properly to the 
sympathetic system. 

The Histology of Nerve-Fibres. ‘The microscope shows 
that in addition to connective tissue and other accessory 
parts, such as blood-vessels, the nervous organs contain tis- 
snes peculiar to themselves and known as nerve-fibres and 
nerve-cells. ‘The cells are found in the centres only; while 
the fibres, of which there are two main varieties known as 
the white and thegray, are found in both trunks and cen- 
tres; the white variety predominating in the cerebro-spinal 
nerves and in the white substance of the centres, and the 
gray in the sympathetic trunks and the gray portions of 
the central organs. 

Tf an ordinary cerebro-spinal nerve-trunk be examined 
it will be found to be enveloped in a loose sheath of areolar 
connective tissue, which forms a packing for it and unites 
it to neighboring parts. From this sheath, or perineurium, 
bands of connective tissue penetrate the nerve and divide 
it up into a number of smaller cords or funiculi, much 
as a muscle is subdivided into fasciculi; each funiculns 
has a sheath of its own called the neurilemma, composed 
of several concentric layers of a delicate membrane, with- 
in which the true nerve-fibres lie, These, which would be 
nearly all of the white kind, consist of extremely delicate 
threads, about 0.0125 millm. (x95 inch) in diameter, but 
frequently of a length which is in proportion very great. 
Each nerve-fibre in fact is continuous from a nerve-centre 
to the organ in which it ends, so that the fibres, e.g. which 
pass out through the sacral plexus and then ranon through 
the sciatic nerve and its branches to the skin of thestoes, are 
three to four feet long. If a perfectly fresh nerve-fibre 


Ss 4 








mM THE HUMAN BODY. 


be examined with the microscope it presents the appear- 
ance of a perfectly homogeneous glassy thread; but soon it 
acquires a characteristic double contour (Fig. 71) from the 
coagulation of a portion of its substance. By proper treat- 
ment with reagents three layers may be brought into view. 
Outside is a fine transparent envelope (1, Fig. 72) called 
the primitive sheath ; inside this is a fatty substance, 2, 


aap 


25 aK 
Ym. TL he. % 





Fra, 71.—White nerve-flhres roon after removal from the Hody and when they 
thelr double contour. 

10. iagram Illustrating the structure of a white or meutlated merve- 

sore” 3,4, peanluve shoatlt; 2°, moduliary swath 5 & ase y tnd 





forming the medullary sheath (the coagulation of which 
gives the fibre its double border), and in the centre is a 
core, the axis cylinder, 3, which is clearly the essential 
part of the fibre, since near its ending the primitive and 
medullary sheaths are frequently absent. At intervals of 
about one millimeter (J inch) along the fibre are found 
wuclei, Those are indications of the primitive cells which 
by their elongation, fusion and other modifications have 





HISTOLOGY OF NERVE-CELLS, 1% 


bnilt up the nerve-fibre, and around each there is a small 
amount of unmodified protoplasm. The medullary sheath 
is interrupted half way between each pair of nuclei at a 
point, called the #ode, which answers to the original bound- 
ary between the two cells. In the course of a nerve-trank 
its fibres rarely divide; when a branch is given off some 
fibres merely separate from the rest, much as a skein of silk 
might be separated out at one end into smaller We aphaned 
taining fewer threads, 

Gray Nerve-Fibres. Some of these are suiraly white 
fibres which near their peripheral ends have lost their me- 
dullary sheaths; but others have no medullary sheath 
throughout their whole course, consisting merely of an 
axis cylinder (often longitudinally striated) and primitive 
sheath, with nuclei. Such fibres are expecially abundant in 
the sympathetic tranks; and they alone are found in the 
olfactory nerve. In the communicating branches between 
the sympathetic ganglia and the spinal nerves both white 
and gray fibres are found; the former being probably 
cerebro-spinal fibres passing into the sympathetic system, 
while the gray fibres originate in the sympathetic system 
and pass into the spinal cord. Another class of gray nerve- 
fibres may be called nerwe-fibrils: they are extremely fine 
and result from the subdivision of axis cylinders, close to 
their final endings in many parts of the Body, after they 
have already lost both primitive and medullary sheaths. 
Many fine gray fibres exist in the nerve-centres. 

The Histology of Nerve-Cells. So far as our knowl- 
edge at present goes the only structures known with cer- 
tainty to be connected with the central ends of nerve-fibros 
are nerve-cells, and these latter may therefore be regarded 
asthe central organs of the nerve-fibres. However, many 
nerve-fibres have not yet been traced into continuity with 
nerve-cells, and possibly end in the centres in othor ways. 

At 1, Fig. 73, is shown a typical nerye-cell such as may 
be found in an anterior horn of the gray matter of the 
spinal cord. It consists of the eel? body, or cell protoplasm, 
in which is a large nucleus containing @ nneleolus, From 
the body of the cell arise several branches, the great ma- 


- 








jority of which subdivi 
gray substance of the spinal cord. One process of the cell, 
however, a, does not branch, but is continued into the an- 
terior root of a spinal nerve, acquiring a medullary and prim- 
itive sheath at 2, and becoming thus the axis cylinder of a 
nerve-fibre. Other nerve-cells (a3 shown at 2 and 4) do not 
possess the peculiar axis-cylinder process; all their branches 
either join the branches of other cella or enter a fine net- 





Fin. £3.—Ditterant forms ot nerve-cells. 1, » cell, one branch of which, a 
becomes the axis cylinder of a nerve-fibre ; 2 two cells united by & pF 
3, diagram of, duree cells united by ranches with one another, and each having 
‘Gu axiscylinder process ; 4 & multipolar cell without an axixeylinder process. 


work of gray nerve-fibrils. Most nerve-cells are larger 
than the majority of the other cells of the Body, their 
average diameter in the anterior horns of the gray sub- 
stance of the cord being 0.1 millimeter (gf, inch). In 
the posterior horns they are smaller, and in the brain 
many minute nerye-cells are found in addition to these 
larger ones, In ganglia the cells asa rule are more reg- 





MINUTE STRUCTURE OF SPINAL CORD. 1777 


ular in outline than those depicted in Fig. 73, and have 
fewer branches, most appearing indeed to have but two. 
Others have been described as possessing only one process 
eonnected with them, and some with none, but the ex- 
istence of these is doubtful, since in separating the cellsfor 
microscopic examination the delicate processes may readily 
‘be broken off and so escape detection. 

‘The Structure of Nerve-Centres. Theseconsist of white 
and gray nerve-fibres, of nerve-cells, and of connective 
tissne and blood-vessels arranged in different ways in the 
different centres. Ganglia are collections of nervo-cells 
and nerve-fibres, some of the latter being connected with 
the cells, while others seem merely to pass through the 
ganglion on their way to other parts, Tho whole mass 
is enveloped and supported by other tissnes. As an illus- 
tration of the structure of a more complex nerve-centre 
we may study the spinal cord, 

Histology of the Spinal Cord. If a thin transverse sec- 
tion of the spinal cord be examined with a microscope it 
will be found to oxhibit the following parts (Fig. 74). 
Enveloping the whole and adherent to the rest is the deli- 
cate layer of connective tissue forming the pia mater. 
This lines the anterior fissure, 1, and an offshoot from it 
fills up the posterior fissure, 2. Elsewhere fine bands of it 
run in and ramify through the cord, supporting the nerv- 
ous elements; some of the coarser of these are represented 
at 6, 7, and elsewhere in the figure, but from these still 
finer processes arise, as represented at @ and ¢ in Fig. 75, 
and surround the individual nerve fibres and cells. This 
ultimate finest connective tissue supporting the nervous 
tissues directly, belongs to the retiform variety (p. 106), 
and is called the neuroglia, In the white columns, the 
cord (Fig. 75) will be seen to be mainly made up of medul- 
lated nerye-fibres which run longitudinally and therefore 
appear in the transverse section as circles, with a dot in 
the centre, which is the axis cylinder. At 6 in Fig. 75 
these fibres are represented, the intermediate connective 
tissue being omitted, while at ¢ this latter alone is repre- 
sented in order to show more clearly its arrangement, At 











178 THE HUMAN BODY. 


the levels of the nerve-roots horizontal white fibres are 
found (9 and 10, Fig. 74, and a, Fig. 75) running into the 
gray matter, and others exist at the bottom of the anterior 
fissure, running from one side of the cord to the other, 
In the gray substance the same supporting network of con- 
nective tissue is found, but in it the majority of the nerve- 
fibres are non-medullated, and at certain points nerve-cells, 





Fro. M4.—A thin transverse section of half of the spinal cont magnified about 
10 diameters. wwerlor fen terior fesury ; 8 canalis centralis : 
8, ia mater enveloping the co ds of pi the card 
‘atid supporting its nerre elements ;'9,'a posterior roo! an ante: 
rior root 5 a, 6, 6 th €, groups of nerve-cells in 











such as are totally absent in the white substance, are found. 
One collection of these norve-cells is seen at ¢ in Fig. 74, 
and others are represented at a, d, f, and elsewhere. The 
nerve-fibres in the gray matter are for the most part 
branches of these cells (seo Pig. 73), and as they unite 
with one another freely they form a stracturally continuous 





HISTOLOGY OF SPINAL CORD, 179 


network through the whole gray substance, The fibres of 
the anterior roots of the spinal nerves enter the gray mat- 
ter and there become continnons with the unbranched pro- 
cess of a nerve-cell; the ending of the posterior root-fibres 
is not quite certain, but they appear to break up and join 
the gray network directly, without the intervention of a 
cell, In any case the fundamental fact remains that every 
nerve-fibre joining the spinal cord is directly or indirectly 
in continuity with the gray network and so with all the 


Tro. .—A eunall bit of the section represented In Fig. T more magnified. 
‘© bundle of Abres from an anterior root passing Le Apna 


pes 
Seriee os craaeo mee emrennee 
porting connective tisaun, d and ¢, Elsewhere the nerve-flbres alone any repre 
7 ¢ enveloping pia mater, 

other fibres of all the spinal nerves. From the sides of the 
gray substance fibres continually pass out into the white 
portion and become medaullated; some of these enter the 
gray network again at another level and so bring parts of 
the cord mto especially close union, while others pass on 
into the brain. At the top of the neck, moreover, the 
gray matter of the cord is continuous with that of the 
medulla oblongata and through it with the rest of the 
brain, so that nervous disturbunces can pass by anatomi- 
cally continuons paths from one to the other, 








CHAPTER XIII. 


THE GENERAL PHYSIOLOGY OF THE NERV- 
OUS SYSTEM, 


The Properties of the Nervous System. (General Con- 
siderations. 1 the finger of any one unexpectedly touches 
a very hot object, pain is felt and the hand is suddenly 
snatched away; that is to say, sensation is aroused and cer- 
tain muscles are caused to contract. If, however, the 
nerves passing from the arm to the spinal cord have been 
divided, or if they have been rendered incapable of activity 
by disease, no such results follow. Pain isnot then felt on 
touching the hot body nor docs any movement of the limb 
oceur; even more, under such circumstances the strongest 
effort of the will of the individual will be unable to cause 
any movement of hig hand. If, again, the nerves of the 
limb have uninjured connection with the spinal cord, but 
parts of the latter, highor up, between the brain and the 
point of junction of the nerves of the brachial plexus with 
the cord, are injured, then a sudden contact with the hot 
body will cause the arm to be snatched away, but no pain 
or other sensation due to the contact will be felt, nor can 
the will act upon the muscles of the arm. From the com- 
parison of what happens in such cases (which have been 
observed over and over again upon wounded or diseased 
persons) with what occurs in the natural condition of 
things, several important conclusions may be arrived at: 

1. The feeling of pain does not reside in the burnt part 
itself; although that may be perfectly normal, no sensa- 
tion will be aroused by any external force acting upon it, 
if the nervous cords uniting it with the centres be pre- 
viously divided. 


2. The hot body has originated some change which, pro- 





GENERAL PROPERTIES OF NERVES. 181 


pagated along the norve-trunks, has excited a condition of 
the nerve-centres which is accompanied by a sensation, in 
this particular case a painful one, This is clear frem the 
fuct that the loss of sensation immediately follows division 
of the nerves of the limb, but not the injury of any of its 
other parts; unless of such a character as to cut off the 
supply of blood, when of course the nerves soon die, with 
the rest. Even, however, some time after tying the vessels 
which carry blood to a limb one can observe in experiments 
upon the lower animals that sensibility is still retained if 
the nerves be not directly injured. 

3. When a nerve in the skin is eccited by a burn or other- 
wise it does not directly call forth muscular contractions; 
for if so, touching the hot body would cause the limb to be 
moved even when the nerve is divided high up in the arm, 
and as a matter of observation and experiment we find 
that no such result follows if the nerve-fibres have been 
cut in any part of their course from the burnt part to the 
spinal marrow. It is therefore through the nerve-centres 
that the change transmitted from the excited part of the 
skin is reflected or sent back, to act upon the muscles. 

4, The last deduction makes it probable that nerve-fibres 
must pass from the centre to muscles as well as from the 
skin to the centre. This is confirmed by the fact that if 
the nerves of the limb be divided the will is unable to act 
upon its muscles, showing that these are excited to con- 
tract throngh the nerves. That the nerve-fibres concerned 
in arousing sensation and muscular contractions are differ- 
ent, is shown also by cases of disease in which the sensi- 
bility of the limb is lost while the power of voluntarily 
moving it remains, and by other cases in which the reverse 
is seen, objects touching the hand being felt while it can- 
not be moved by the will. We conclude then that cer- 
tain nerve-fibres when stimulated convey something (a 
nervous impulse) to the centres, and that these when ex- 
cited may radiate impulses through other nerve-fibres to 
distant parts, the centre serving as a connecting link be- 
tween the fibres which carry impulses from without in, and 
those which convey them from within out. 








182 THE HUMAN BODY. 


5. Further we conclude ‘hat the spinal cord can act as 
an intermediary between the fibres carrying in nervous im- 
pulses and those carrying them out, but that sensations can- 
not be aroused by impulses reaching the spinal cord only, 
nor has the Will its seat there ; volition and consciousness are 
dependent upon states of the brain. This follows from the 
linconscioas movements of the limb which follow stimula- 
tion of its skin after such injury to the spinal cord as pre- 
vents the transmission of nervous impulses farther on 
(showing that the cord is a reflex centre), and from the 
absence, in such cases, of sensation in the part whose nerves 
have been injured, and the loss of the power of voluntarily 
causing its muscles to contract. 

6. Finally we conclude that the spinal cord in addition 
to being a centre for reflex actions serves also to transmit 
onwards nervous impulses to the brain; a fact which is con- 
firmed by the histological observation that in addition to 
the nerve-cells, which are the characteristic constituents of 
nerve-centres, it contains the simply conductive nerve- 
fibres, many of which pass on to the brain. In other 
words the spinal cord, besides containing fibres which enter 
it from, and pass from it to, peripheral parts contains 
many which unite it to other centres; and connect the 
yurious centres in it, as those for the arms and legs, to- 
gether. This is true not only of the spinal cord but of the 
brain (which contains many fibres uniting different centres 
in it),and probably of all nerve-centres, 

The Functions of Nerve-Centres and Norve-Trunks, 
From what has been stated in the previous paragraphs it is 
elear that we may distinctly separate the nerve-trunks from 
the nerve-centres. ‘The fibres serve simply to convey im- 
pulses either from without toa centre or in the opposite 
direction, while the centres conduct and do much more. 
Some, as the spinal cord,are merely reflex centres, and have 
nothing to do with states of consciousness. A man with 
his spinal cord cut or diseased in the dorsal region will 
kick violently if the soles of his feet be tickled, but will 
feel nothing of the tickling, and if he did not see his legs 
would not know that they were moving. Reflex centres 





FUNCTIONS OF NERVE-CENTRES. 183 


moreover do not act, a8 a rule, indifferently and casually, 
but rearrange the impulses reaching them, so as to pro- 
duce a protective or in some way advantageous result. In 
other words, these centres, acting in health, commonly eo- 
ordinate the incoming impulses and give rise to outward- 
going impulses which produce an apparently purposive 
result. ‘The burnt hand or the tickled foot, in the absence 
of all consciousness, are snatched away from the irritant, 
and food chewed in the mouth excites nerves there which 
act on a centre which causes certain cells in the salivary 
glands to form and pour into the month more saliva. In 
addition to the reflex centres we have others, placed in the 
brain, and which, when excited, cause in us various states 
of consciousness, as sensations, emotions, and the will; 
concerning these centres of consciousness, however, our 
physiological knowledge is still very incomplete and so they 
are still largely grouped by psychologists according to their 
individual fancy. The brain also contains a great many 
important reflex centres, as that for the muscles of swallow- 
ing, an act which goes on perfectly without our conscious- 
ness at ull. In fact if we pay attention to our swallowing 
we fail to perform it as well as if we let the nervo-muscular 
apparatus alone. ‘To complete the statement of the func- 
tions of the nerve-centres we must probably add two other 
groups. The firstof these is that of the automatic centres, 
which are centres excited not directly by nerye-fibres con- 
voying impulses to them, but in other ways. For exumple 
the breathing movements go on independently of our con- 
sciousness, being dependent on stimulation of a nerve-centre 
in the brain by the blood which flows through it (see Chap. 
XXVL};and the beat of the heart is also dependent (Chap. 
XYVIL) upon nerve-centres the excitant of which is un- 
known. The final group of nerve-contres is represented 
ly certain sporadic symputhetie and cerebro-spinal gunglia 
which are not known to be either reflex, automatic, or con- 
scious in function, They may be called relay and june- 
tion centres, since in them probably an impulse entering 
by one nerve-fibre excites a cell, which by its communi- 
cating branches arouses many others, and these send ont 








184 THE HUMAN BODY. 


impulses then by the many nerve-fibres connected with 
them. By such means a single nerve-fibre can act upon 
an extended region of the Body. In other cases it seems 
likely that a feeble neryous impulse reaching an irritable 
nerve-cell excites changes in this comparable to those pro- 
duced in a muscle when it is stimulated; and the cell by 
its discharge sends on reinforced nerve impulses along its 
other branches. 

Excitant and Inhibitory Nerves. The great majority 
of the nerve-fibres of the Body when they convey nervous 
impulses to a part arouse it to activity; they are ezcitané 
Jibres. There is, however, in the Body another very im- 
portant set which arrest the activity of parts and which 
are known as inhibitory nervesfibres. Some of these check 
the action of central nervous organs, and others the work 
of peripheral parts. For instance taking a pinch of enuff 
will make most persons sneeze; it excites centrally acting 
fibres in the nose, these excite a centre in the brain, 
and this in turn sends ont impulses by efferent fibres which 
cause Yarious muscles to contract. But if the skin of the 
upper lip be pinched immediately after taking the snuff, in 
most cases the reflex act of sneezing, which the Will alone 
could not prevent, will not take place. The afferent im- 
pulses conveyed from the skin of the lip have ‘‘ inhibited” 
what we may call the ‘‘sneezing centre;” and afford us 
therefore an example of inhibitory fibres checking a centre. 
On the other hand, the heart is a muscular organ which 
goes on beating steadily throughout life; but if the branches 
of the pneumogustrie nerve to it be excited, the beat 
of the heart will be stopped; it will cease towork and lie in a 
relaxed resting condition: in this we have an instance of an 
inhibitory nerve checking tho activity of a peripheral organ. 

Classification of Nerve-Fibres. Nearly all the nerve- 
fibres of the Body fall into one of two great groups corre- 
sponding to those which carry impulses to the centres 
and those which carry them out from the centres. 
The former are called afferent or centripetal fibres and the 
latter efferent or centrifugal. Since the impulses reaching 
tho centres through the afferent fibres generally cause sen- 











[ ra e 


CLASSIFICATION OF NERVE-FIBRES. 185 


sations they are often called sensory fibres; and as many of 
those which carry out impulses from the centres excite 
movements, they are frequently called motor fibres; but 
these last names are bad, since even excluding inhibi- 
tory nerves, many afferent fibres are not sensory and many 
efferent are not motor. 

We may distinguish as subdivisions of afferent fibres—the 
following groups, 1. Sensory fibres proper, the excitement 
of which is followed bya sensation when they are con- 
nected with their brain-centre, which sensation may or 
may not give rise to a voluntary movement. 2. Reflex 
Jibres, the excitation of which may be attended with con- 
sciousness but gives rise to involuntary efferent impulses, 
Thus for example light falling on the eye causes not only 
asensation but also a narrowing of the pupil, which is en- 
tirely independent of the control of the Will. No absolute 
line can, however, be drawn between these fibres and those 
of the last group: any sudden excitation, as an unexpected 
noise, will cause an involuntary movement, while the same 
sound if expected would cause a movement or not accord- 
ing as was willed. 3. Bzeito-motor fibres. The excitation 
of these when reaching a nerve-centre causes the stimula- 
tion of efferent fibres, but without the participation of 
consciousness, During fasting for instance bile accumu- 
lates in the gall-bladder and there remains until some 
semi-digested food passes from the stomach into the intes- 
tine. This is acid, and stimulates nerves in the mucons 
membrane lining the intestine, and these convey an im- 
pulse to a centre, which in consequence sends out impulses 
to the muscular coat of the gall-bladder causing it to con- 
tract and expel its contents into the intestine: but of all 
this wo are entirely unconscious. 4. Contro-inhibitory 
Sibres. Whether these exist as a distinct class is at present 
doubtful. It may be that they are only ordinary sensory 
or reflex fibres and that the inhibition is due only to tho in- 
terference of two impulses reaching a central organ at the 
same time and impeding or hindering the full production 
of the normal result of either. 

Tn efforent norve-fibres physiologists also distinguish 





186 THE HUMAN BODY. 





several groups. 1, Motor jibres, which are distributed to 
the muscles and govern their contractions, 2. Vaso-motor 
fibres, These are not logicully separable from other motor 
fibres; but they are distributed to the museles of the blood- 
vessels and by governing the blood-supply of various parts, 
indirectly produce such secondary results as entirely over- 
shadow their primary effect as merely producing muscular 
contractions. 3, Secretory fibres. hese are distributed 
to the cells of the Body which form various liquids used in it, 
as the saliva and the gustric juice, and arouse them to ac- 
tivity. ‘The salivary glands for instance may be made to 
form saliva by stimulating nerves going to them, and the 
same is true of the cells which form the sweat poured out 
upon the surface of the Body. 4. Trophic nerve-fibres. 
Under this head are included nerve-fibres which have been 
supposed to govern the nutrition of the various tissues, and 
a0 to control their healthy life, It is very doubtful, how- 
ever, if any such nerve-fibres exist, most of the facts cited 
to prove their existence being otherwise explicable. For 
instance shingles is a disease characterized by an eruption 
on the skin along the line of certain nerves which run be- 
tween the ribs; bat it may be dependent upon disease of 
the yaso-motor nerves which control the blood-supply of 
the part. In other cases diseases ascribed to injury of 
trophic nerves have been shown to be due to injury 
of the sensory nerves of the part, which having lost its 
feeling, is exposed to injuries from which it would other- 
wise have been protected. On the other hand it may be 
said that secretory nerves are trophic nerves in the true 
sense of the word, since when excited they cause the se- 
cretory cells to live in a special way (p. 269) and produce 
substances which when unacted upon by their nerves they 
donot form. But if we call secretory nerves trophic we 
must include also under that name all other efferent 
nerves; the nutritive processes going on in a muscular 
fibre when at work are different from those in the same 
fibre when at rest, and the same is true of all other cells 
the activity of which is governed by nerve-fibres, 5. Peri- 
Phorally-acting inhibitory nerves. 





NERVE STIMULL, 187 


Intercentral Nerve-Fibres. Those, which do not convey 
impulses to or from peripheral parts and nerve-centres, but 
connect one centre with another, form a final group in ad- 
dition to efferent and afferent nerve-fibres. Many of them 
connect the sporadic and sympathetic ganglia with ove 
another and with the cerebro-spinal centre, while others 
place different parts of this latter in direct communication; 
as for instance different parts of the spinal cord, the brain 
and the spinal cord, and the two halves of the brain. 
These fibres are of very great importance, but as yet their 
course is imperfectly known, 

General Tablo, We may physiologically classify nerve- 
fibres as in the following tabular form which is founded 
upon the facts above stated. 


Sensory. 
Reflex. 
Excito-motor. 
Tahibitory? 


Afferent. 


{ Motor. 
eee 
Efferent. | Bceretory. 


Nerve-fibres, 


‘Trophic t 
Inhibitory. 


| 
Pectpeh. 9 : 
| 


Tntercontral, | ey. 

Tho Stimuli of Nerve-Fibres. Norve-fibres, like mus- 
cular fibres, possess no automaticity; acted upon by certain 
external forces or stimuli they propagate a change, which is 
known as a nervous impulse, from the point acted upon to 
their ends; but they do not generate nervous impulses when 
left entirely to themselves. Normally, in the living Body 
the stimulus acts on a nerve-fibre at one of its ends, being 
either some change in a nerve-centro with which the fibre 
is connected (efferent nerves) or some change in an organ 
attached to the outer end of the nerve (afferent fibres). 
Experiment shows, however, that a nerve can be stimulated 
in any part of its course; that it is irritable all through its 








188 THE HUMAN BODY. 


extent. If, for example, the sciatic of a frog be exposed in 
the thigh and divided, it will be found that electric shocks 
applied at the point of division to the outer half of the 
nerve stimulate the motor fibres in it, and cause the mus- 
cular fibres of the leg to contract: and similarly such shocks 
applied to the eutend of the central half irritate the affe- 
rent fibres in it, as shown by the signs of feeling exhibited 
by the animal. In ourselves, too, we often have the oppor- 
tunity of observing that the sensory fibres can be stimulated 
in their course at some distance from their ends. A blow 
at the back of the elbow, at the point commonly known as 
the “funny bone” or the ‘crazy bone,” compresses the 
ninar nerve there against the subjacent bone, and starts 
nervous impulses which make themselves known by severe 
tingling pain referred to the little and ring fingers to which 
the nerve is distributed. This shows not only that the 
nerve-fibres can be irritated in their course as well as at 
their ends, but also that sensations do not directly tell us 
where a nerve-fibre has been excited. No matter where in 
its course the impulse has been started we unconsciously 
refer its origin to the peripheral end of the afferent nerve. 
General and Spocial Nerve Stimuli. Certain external 
forces excite all nerve-fibres, and in any part of their course. 
These are known as general nerve stimuli; others act only 
on the end organs of nerve-fibres, and often only on one 
kind of end orgun, and hence cannot be made to excite all 
nerves: these latter are commonly known as special nerve 
stimuli. Yn reality they are not properly nerve stimuli at 
all; but only things which so affect the irritable tissues at- 
tuched to the ends of certain nerve-fibres as to make these 
tissues in turn excite the nerves. For example light itself 
will not stimulate any nerve, not even the optic: but in the 
eye it effects changes (apparently of a chemical nature) 
by which substances of the nature of general nerve stimuli 
are produced and these stimulate the optic nerve-fibres. 
‘The ends of the nerves in the skin are not accessible to 
light nor are the proper end organs on which the light 
ucts there present, so light does not lead to the production 
of nervous impulses in them: but the optic nerve without 








NERVE STIMULI. 189 


its peenliar end organs would be just ss insensible to light 
as these are. Similarly the aérial vibrations which affect 
us as sounds, do not stimulate directly the fibres of the andi- 
tory nerve. They act on terminal organs in the ear, and 
these then stimulate the fibres of the nerve of hearing, just 
as they would any other nerve which happened to be con- 
nected with them. 

General Nerve Stimuli. Those known are (1) electric 
currents: an electric shock passed through any part of 
any nerve-fibre, powerfully excites it. A steady current 
passing through a nerve does not stimulate it, but any 
sudden change in this, whether an increase or a decrease, 
does. A very gradual change in the amount of electricity 
passing through « nerve ina unit of time will not stimu- 
late it. (2) Mechanical stimuli, Any sudden pressure 
or traction, as a blow or a pull, will stimulate a nerve- 
fibre. On the other hand steady pressure, or pressure very 
slowly increased from a minimam, will not excite the 
nerve. (3) Thermal stimuii. Any sudden heating or cool- 
ing of a nerve, as for instance bringing a hot wire close to 
it, will stimulate; slow changes of temperature will not, (4) 
Chemical stimuli. Many substances which alter the nerve- 
fibre chemically, stimulate before killing it; thus dipping 
the cut end of a nerve into strong solution of common salt 
will excite it, but very slow chemical change in a nerve 
fails to stimulate, 

Tn the case of all these general stimuli it will be seen 
that as one condition of their efficacy they must act with 
considerable snddenness. On the other hand too transient 
influences have no effect. An electric shock sont for only 
0.0015 of a second through a nerve does not stimulate 
it: apparently the inertia of the nerve molecules is too 
great to be overcome by so brief an action. So, also, too 
strong sulphuric acid and many other bodies kill nerves 
immediately, altering them so rapidly that they die without 
being stimulated. 

Special Nerve Stimuli, These as already explained 
act only on particular nerves, not because one nerve is es- 
sentially different from another, but because their influence 








190 THE HUMAN BODY. 


is excited through special end organs which are peculiar to 
some nerves, Those stimuli are—(1) Changes occurring in 
central organa, of whose nature we know next to nothing, 
ut which excite the efferent nerve-fibres connected with 
them. The remaining special etimuli act on afferent fibres 
through the sense-organs. They are—(2) Light,which by the 
intervention of organs in the eye excites the optic nerve. (2) 
Sound, which by the intervention of organs in the ear excites 
the auditory nerve. (3) Heat, which through end organs in 
the skin is able, by very slight changes, to excite certain 
nerve-fibres: such slight changes of temperature being 
efficient as would be quite incapable of acting a3 general 
nerve stimuli without the proper end organs. (4) Chemical 
agencies. ‘These when extremely feeble and incapable of 
acting as general stimuli, can uct us special stimuli through 
apecial end organs in the mouth and nose (as in taste and 
smell) and probably in other parts of the alimentary tract, 
where very feeble acids and alkalies seem able to excite 
certain nerves, and reflexly through them excite movements 
or stir up the cells concerned in making the digestive 
liquids; for example the contraction of the gall-bladder 
already referred to, (5) Mechanical stimuli when so feeble 
as to be inefficient as general stimuli. Pressure on the 
ekin of the forehead or the back of the hand, equal to .002 
gram (.03 grain) can be felt through the end organs of 
the sensory fibres there, but would be quite incapable of 
acting as a general stimulus in the absence of these. 

Tt will be noticed as regards the special stimuli of 
afferent nerves that many of them are merely leas degrees 
of generai stimuli; the end organs in akin, mouth,and nose 
are in fuct excited by the same things as the nervo-flbres, 
but are far more irritable. In the case of the higher 
senses, seeing and hearing, however, the end organs seem 
to differ entirely in property from nerve-fibres, being 
excited by sonorous and luminous vibrations which, so far 
as we know, will in no degree of intensity directly excite 
nerve-fibres. ‘To make an end organ for recognizing very 
slight pressures we may imagine all that would be needed 





SPECIFIC NERVE ENERGIES wm 


would be to expose directly a very delicate end branch of 
the axis cylinder, and this seems in fact to be the case in 
the nerves of the transparent exposed part of the eyeball, if 
not in many other parts of the external integument of the 
Body. But as axis cylinders are quite unirritable by light 
or sound 4 mere exposure of them would be useless in the 
eye or car, and in each case we find accordingly a very 
complex apparatus developed, whose function it is to 
eonvert these modes of motion which do not excite nerves 
into others which do. We might compare it to a 
cartridge, which contains not only “ irritable” gunpowder 
but highly “irritable” detonating powder, and the stimulus 
of the blow from the hammer which would not itself ignite 
the gunpowder, acting on the detonating powder (which 
represents an “‘end organ”), causes it to give off a spark 
which in turn excites the gunpowder, which answers to the 
nerve-fibre. 

Specific Nerve Energies. We have already seen that a 
nervous impulse propagated along a nerve-fibre will give 
rise to different results according aa different nerve-fibres 
are concerned. Traveling along one fibre it will arouse a 
vensation, along another a movement, along a third a se- 
eretion. In addition we may observe readily that these 
different results may be produced by the same physical 
force when it acts upon different nerves, Radiant energy, 
for example, falling into the eye causes a sensation of 
sight, but falling upon the skin one of heat, if any. The 
different results which follow the stimulation of different 
nerves do not then depend upon differences in the physical 
forces exciting them. This is still further shown by the 
fact that different physical forces acting upon the same 
nerve arouse the same kind of sensation. Light reaching 
the eye causes a sight sensation, but if the optic nerve be 
irritated by a blow on the eyeball a sensation of light is 
felt just as if actual light had stimulated the nerve ends, 
So too when the optic nerve is ent by the surgeon in ex- 
tirpating the eyeball, the patient experiences the sensation 
of a flash of light; and the same result follows if an electric 








194 THE HUMAN BODY. 


along the fibre. If the muscle were eut away from the end 
of the nerve we could still detect that a nervous impulse 
had trayeled from the point of stimulation to that where 
the fibres were divided, by tracking the negative variation. 
Now if we examine the part of the nerve on the central 
side of the stimulated point we find that a negative varia- 
~ tion (and hence we conclude a nervous impulse) travels that 
way too; it starts at the same moment as the efferent nega- 
tive variation and travels in the same way, but the impulse 
of which it is asign produces no more effect than the efferent 
impulse would after the muscle had been cut away; for it 
does not reach any muscular fibre, or sensory or reflex centre, 
which it can arouse to activity. (4) The following experi- 
ment is, however, more conclusive. If a rat’s tail be am- 
putated close to the body of the animal and be then trans- 
planted to the back and sewn into the skin there by its 
narrow end, it will grow in this new position, with the 
‘broad end, which was previously attached and nearcst the 
spinal cord, now free and farthest from it, The tail, in 
other words, will be upside down. After the wound has 
healed, the nerve-fibres in the tail, or some of them, attach 
themselyes to the cut nervo-fibres in the wound of the 
back to which it was transplanted, and the tail again be- 
comes sensitive if the end now free be pinched. Here one 
of two things must have occurred. Hither the afferent 
nerye-fibres in the tail which naturally carried impulses 
from its tip up, now carry them in the opposite direction 
from the broad end to the tip, or the efferent nerve-fibrox 
which carried motor impulses down the tail, now carry sen- 
sory impulses and transmit them to the sensory fibres in 
the back with which they have become continuous. If the 
first, which is the more probable hypothesis, be true, it 
is proved that afferent nerve-fibres can carry impulses in 
either direction: if the second be true it is still more clear 
that there is no special peculiarity in a sensory nervous 
impulse when compared with a motor, 
Afferent and efferent nerve-fibres then differ in no 
observable property, All are alike in faculty and their 
different names simply imply that they haye different ter- 





SIMILARITY OF ALL NERVE-FIBRES, 195 


minal organs. Just as all muscles are alike in general 
physiological properties, and differ in special function 
according to the parts on which they act, so are all nerve- 
fibres alike in general physiological properties, and differ 
in special function only because they are attached to spe- 
cial things. The special physiology of various nerves will 
hereafter be considered in connection with the working of 
various mechanisms in the Body. If it be true that the 
great subdivisions of afferent and efferent fibres have 
identical properties, it follows that this is a fortior® true 
of the minor subdivisions of each, and that auditory, gus- 
tatory, and optic nerve-fibres are all alike, and all identi- 
eal with motor and vaso-motor and secretory nerve-fibres; 
and that the nervous impulse is in all cases the same thing, 
varying in intensity in different cases and in the rate ut 
which others follow it in the same fibre, but the same in 
kind. ‘To put the case more definitely: Light outside the 
eye exists as ethereal vibrations, sound outside the ear as 
vibrations of the air (commonly). Each kind of vibration 
acts on a particular end organ in eye or ear which is 
adapted to be acted upon by it, and in tarn these end 
organs excite the optic and auditory nerve-fibres; these in 
consequence transmit impulses, which reaching different 
parts of the brain excite them; the excitement of one of 
these brain-centres is associated with sonorous and of the 
other with visual sensations. ‘The nervous impulse in the 
two cases is quite alike, at least as to quality; though it may 
differ in quantity and rhythm, and the resulting difference 
in quality of the sensations cannot depend on it, The 
quality differences in these cases must be products of the 
central nervous system. If we had a set of copper wires we 
might by sending precisely similar electric currents through 
thom produce very different results if different things were 
interposed in their course. In one case the current might 
be sent through water and decompose it, doing chemical 
work; in another through the coil of an electro-magnet 
and raise a weight; in a third through a thin platinum 
wire and develop light and heat, and so on; tho result 
depending on the terminal organs, us we may call them, 








196 THE HUMAN BODY, 


of each wire, Or on ihe other hand we might gen- 
erate the current in each wire differently, in one by a 
Daniell’s cell, in a second by a thermo-electric machine, 
in a third by the rotation of a magnet inside a coil, but the 
currents in the wires would be essentially the same, as the 
nervous impulses are ina nerve-fibre. No matter how 
they have been started and, provided their amount is the 
same, whether they produce similar or dissimilar results, 
depends only on whether they are connected with similar 
or dissimilar end organs. 

‘The Nature of a Nervous Impulse. Since between 
sense-organs and sensory centres, and these latter and the 
muscles, neryous impulses are the only means of communi- 
cation, itis through them that we arrive at our opinions 
concerning the external universe and through them that 
we are able to act upon it; their ultimate nature is there- 
fore u matter of great interest, but one abont which we 
unfortunately know very little. We cannot well ima- 
gine it anything but a mode of motion of the molecules of 
the nerve-fibres, but beyond this hypothesis we cannot go 
far. In many points the phenomena presented by nerve- 
fibres as transmitters of disturbances are like the phenom- 
ena of wires as transmitters of electricity, and when the 
phenomena of current electricity were first observed there 
‘was a great tendency, explaining one unknown by another, 
to consider nervous impulses merely as electrical currents. 
‘The increase of our knowledge concerning both nerves and 
electric currents, however, has made such an hypothesis 
almost if nob quite untenable. In the first place, nerve- 
fibres are extremely bad conductors of electricity, so bad 
that it is impossible to suppose them used in the Body for 
that purpose, and in the second place, merely physical con- 
tinuity of a nerve-fibre, such as would not interfere with 
the passage of an electric current, will not suffice for the 
transmission of a nervous impulee. For instance if a damp 
string be tied around a nerve, or if it be eut and its two moist 
ends placed in contact, no nervous impulse will be trans- 
mitted across the constricted or divided point, although 
an electrical current would pass readily. An electrical 





FUNCTIONS OF THE SPINAL ROOTS. 197 


shock may be used like many other stimuli to upset the 
equilibrium of the nerve molecules and start a nervous im- 
pulse, which then travels along the fibre, but is just as dif- 
ferent from the stimulus exciting it, as a muscular contrac- 
tion is from the stimulus which calls it forth, 

‘The nerves, however, have certain interesting electrical 
properties from the study of which we learn some little 
about-a nervous impulse. As already mentioned whenever 
a nervous impulse is started in a nerve an electrical change, 
known as the “ negative variation” or *‘ action current,” is 
started at the came time, from the same point, and travels 
along the nerve at the same rate, Hence we conclude that 
the new internal molecular arrangement in a nerve-fibre 
which constitutes ite active as compared with its resting 
state, is also one which changes the electrical properties of 
the fibre. It is an outward sign and the only known one 
of the internal change. Now it is found that the action 
current travels along the nerve (in the frog) at the rate of 28 
meters (92.00 feet) in a second and takes .0007 second to 
pass by a given point: accordingly at any one moment it 
extends over about 18 mm. (0.720 inch) of the nerve- 
fibre. Moreover, when first reaching a point it is very 
feeble, then rises to a maximum and gridually fades away 
again. Taking it as an indication of what is going on in 
the nerve, we may assume that the nervous impulse is a 
molecular change of a wavelike character, rising from a 
minimum toa maximum, then gradually ceasing, and about 
18 millimeters in length. 

The Rate of Transmission of a Nervous Impulse. 
This can be measured in several ways, and is far slower than 
that of electric currents. It agrees as above stated with 
that of the negative variation, being 28 meters (92.00 feet) 
per second in the motor nerves of a frog. In man it is 
somewhat quicker, being 33 meters (108.24 feet) per second, 
that is about 5 of the rate of the transmission of sound- 
waves in air at xero, 

Functions of the Spinal Nervo-Roots. The great ma- 
jority of the larger nerve-trunks of the Body contain both 
afferent and efferent nerve-fibres, If one be exposed in its 





“198 THE HUMAN BODY. 





course and divided in a living animal, it will be found that 
irritating its peripheral stump causes muscular contractions, 
and pinching its central stump causes signs of sensation, 
showing that the trunk contained both motor and sensory 
fibres. If the trunk be followed away from the centre, as 
it breaks up into smaller and smaller branches, it will be 
found that these too are mixed until very near their end- 
ings, where the very finest terminal branches close to the 
end organs, whether muscular fibres, secretory cells, or sen- 
sory apparatuses, contain only afferent or efferent fibres, 
If the nerve-trunk be one that arises from the spinal cord 
and be examined progressively back to its origin, it will 
still be found mixed, up to the point where its fibres sepa- 
rate to enter either an anterior or a posterior nerve-root. 
Each of these latter however is pure, all the efferent fibres 
of the spinal nervea leaving the cord by the anterior roots, 
and all the afferent entering it by the posterior. This of 
course could not be told from examination of the dead 
nerves since the best microscope fails to distinguish an 
afferent from an efferent fibre, but is readily proved by 
experiments first performed by Sir Charles Bell. If an 
anterior root be cut and its outer end stimulated, the mus- 
cles of the parts to which the trunk which it helps to form 
is distributed, will be made to contract, and the skin will 
be made to sweat also if the root happen to be one that 
contains secretory fibres for the sweat-glands. On the other 
hand, if the central end of the root (that part of it attached 
to the cord) be stimulated no result will follow, showing that 
the root contains no sensory, reflex, or excito-motor fibres. 
With the posterior roots the reverse is the case; if one of 
them be divided and its outer end stimulated, no observed 
result follows, showing the absence of all efferent fibres; 
but stimulation of its central end will cause either signs 
of feeling, or reflex actions, or both. We might compare » 
spinal nerve-trank to a rope made up of green and red 
threads with at one end all the greon threads collected into 
one skein and the red into another, which would represent 
the roots. At its farther end we may suppose the rope 
divided into finer cords, each of these also containing 





COMMUNICATION OF NERVE-CENTRES, 199 


red and green threads down to the very finest branches 
consisting of only a few threads and those all of one kind 
either red or green, one representing efferent, the other 
afferent fibres. 

Tho Cranial Nerves. Most of these are mixed also, but 
with one exception (the fifth pair, the small root of which 
is efferent and the large gangliated one afferent) they do not 
present distinct motor and sensory roots, like those of the 
spinal nerves, At their origin from the brain most of them 
are either purely afferent or efferent, and the mixed char- 
acter which their trunks exhibit is due to cross-branches 
with neighboring nerves, in which afferent and efferent 
fibres are interchanged. The olfactory, optic, and andi- 
tory nerves remain, however, purely afferent in all their 
course, and others though not quite pnre contain mainly 
efferent fibres (as the facial) or mainly afferent (as the 
gloaso-pharyngeal), 

‘Phe Intercommunication of Nerve-Centres. From the 
anatomical arrangement of the nervous system it is clear 
that it forms one continuous whole. No subdivision of it 
is isolated from the rest, but nerve-trunks proceeding from 
the centres in one direction bind them to various tissues 
and, proceeding in another, to other nerve-centres; which 
in turn are united with other tissues and other centres, 
Since the physiological character of a nerve-fibre is its con- 
ductivity—its power of propagating a disturbance when 
once its molecular equilibrium has been upset at any one 
point—it is obvious that through the nervous system any 
one part of the Body, supplied with nerves, may react on all 
other parts (with the exception of such as hairs and nails 
and cartilages, which are not known to possess nerves) and 
excite changes in them. Pre-eminently the nervous system 
forms « uniting anatomical and physiological bond through 
the agency of which unity and order are produced in the 
activities of different and distant parts. We may compare 
it to the Western Union Telegraph, the head office of 
which in New York would represent the brain and spinal 
cord; the more important central offices in other large 
cities, the sympathetic ganglia; and the minor offices in 








200 THE HUMAN BODY. 


country stations the sporadic ganglia; while the tele- 
graph-wires, directly or indirectly uniting all, would corre- 
spond tothe nerve-tranks. Just asinformation started along 
some outlying wire may be transmitted to a central office, 
and from it to others, and then, according to what happens 
to it in the centre, be stopped there, or spread in all diree- 
tiona, or in one or two only, 80 may a neryous disturbance 
reaching a centre by one nerye-trunk merely excite changes 
in it or be radiated from it through other trunks more 
or less widely over the Body and arouse various activi- 
ties in its other component tissues. In common life the 
very frequency of this uniting activity of the nervous sys- 
tem is such that we are apt to entirely overlook it. We 
do not wonder how the sight of pleasant food will make the 
mouth water and the hand reach out for it; it seems as we 
say “natural” and to need no explanation. But the eye 
itself can excite no desire, cause the secretion of no saliva, 
and the movement of no limb. The whole complex result 
depends on the fact that the eye is united by the optic 
nerve with the brain, and that again by other nerves with 
saliva-forming cells, and with muscular fibres of the arm; 
and through these a change excited by light falling into 
the eye is enabled to produce changes in far removed or- 
gans and excite desire, secretion and movement. In cases 
of disease thisaction exerted at a distance is more apt to ex- 
cite our attention: vomiting is a very common symptom of 
certain brain diseases and most people know that a disor- 
dered stomach will produce a headache; while the pain 
consequent upon the hip-disease of children is usually felt 
not at the hip-joint but at the knee. 








CHAPTER XIV. 


THE ANATOMY OF THE HEART AND BLOOD. 
VESSELS, 


General Statement. During life the blood is kept flow- 
ing with great rapidity through all parts of the Body (ex- 
cept the few non-vascular tissues already mentioned) in 
definite paths prescribed for it by the heart and blood- 
vessels. These paths, which under normal circumstances 
it never leaves, constitute a continuous 
set of closed tubes (Fig. 76) beginning 


at and ending again in the heart, and 

simple only close to that organ. Else- 

where it is greatly branched, the most 

numerous and finest branches (2 and a) 

being the capillaries. ‘The heart is es- 

sontially # bag with muscular walls and 

internally divided into four chambers 

(d, g, 0, f). Those at one end (d and e) 

receive blood from yessels opening into 

them and known ag the veins, From 

there the blood passes on to the remain- 

ing chambers (g and ) which have very 

powerful walls and, forcibly contract- 

ing, drive the bleod ont into vessels 

(@ and 4) which communicate with t 
them and are known as the arteries. graniiaatically ye pre- 
The big arteries divide into smaller; 

these into smaller again (Fig. 77) until the branches be- 
come too small to be traced by the unaided eye, and these 
smallest branches end in the capillaries, through which the 
blood flows and enters the commiencements of the veins; 








202 THE HUMAN BODY. 


and these convey it again to the heart. At certain point 
in the course of the blood-paths valves are placed, whiel 
prevent a back-flow. his alternating reception of bloo 
at one end by the heart and its ejection from the other g 





Fio. T7.—The arteries of the hand, showing the communications or annat« 


moses of different arteries and the fine termina) twigs given off from the large 
trunks; these twigs end in the capillaries which would only be visible if mag 
nifled. "X, the radéal artery on which the pulse is usually felt at the wrist ; 
the ulnar artery. 





on during life steadily about seventy times in a minute 
and so keep the liquid constantly in motion. 

The vascular system is completely closed except at tw! 
points where the lymph-vessels open into the veins (p. 329) 
there some lymph is poured in and mixed directly with th 
blood. Accordingly everything which leaves the blow 


POSITION OF THE HEART. 208 


must do so by oozing through the walls of the blood-vessels, 
and everything which enters it must do the same, except 
matters conveyed in by the lymph at the points above 
mentioned. This interchange through the walls of the 
vessels takes place only in the capillaries, which form a sort 
of irrigation system all through the Body. The heart, 
arteries, and yeins are all merely arrangements for keeping 
the capillaries full and renewing the blood within them. 
It is in the capillaries alone that the blood does its phy- 
siological work. 

‘Phe Position of the Heart. ‘The heart (4, Fig, 1) lits 
in the chest immediately above the diaphragm and oppo- 
site the lower two thirds of the breast-bone. It is conical 
in form with its dase or broader end turned upwards and 
projecting a little on the right of the sternum, while its 
narrow end or apex, turned downwards, projects to the left 
of that bone, where it may be felt beating between the 
cartilages of the fifth and sixth ribs, The position of the 
organ in the Body is therefore oblique with reference to its 
long axis. It does not, however, lie on the left side as is 
so commonly supposed but very nearly in the middle line, 
with the upper part inclined to the right, and the lower 
(which may be easier felt beating—hence the common 
belief) to the left. 

Tho Mombranes of tho Heart. The heart does not lie 
bare in the chest but is surrounded bya loose bag composed 
of connective tissne and called the pericardium. This bag, 
like the heart, is conical but turned the other way, ite broad 
part being lowest and attached to the upper surface of the 
diaphragm. Internally it is lined bya smooth serous mem- 
brane like that lining the abdominal cavity, and a similar 
layer (the visceral layer of the pericardium) covers the out- 
side of the heart itself, adhering closely to it: Each of the 
serous layers is covered by a stratum of flat cells, and in the 
space between them is found a small quantity of liquid 
which moistens the contiguous surfaces, and diminishes the 
friction which would otherwise occur during the movements 
of the heart. 

Internally the heart is also lined by a fibrous membrane, 





204 THE HUMAN BODY. 





covered with a single layer of flattencd cells, and called the 
endocardium. Between the endocardium and the viscerai 
layer of the pericardium the balk of the wall of the heart lies 
and is made up mainly of striped muscular tissue (differing 
somewhat from that of the skeletal muscles); but connective 
tissues, blood-vessels, nerve-cells, and nerve-fibres are also 
abundant in it. 

Note. Sometimes the pericardium becomes inflamed, 
this affection being known as pericarditis. It is extremely 
apt to occur in acute rheumatism, and great care should 
be taken never, even for a moment, except under medical 
advice, to expose a patient to cold during that disease, 
since any chill is then especially apt to set up pericarditis. 
In the earlier stages of pericardiac inflammation the rubbing 
surfaces on the outside of the heart and the inside of the 
pericardium become roughened, and their friction produces 
asound which can be recognized through the stethoscope. 
In later stages great quantities of liquid may accumulate in 
the pericardium so as to seriously impede the heart’s 
beat. 

‘The Cavities of the Heart. n opening the heart (see 
diagram, Fig. 78) it is 
found to be subdivided 
by a longitudinal parti- 
tion or septum into 
completely separated 
right und left halves, 

\ the partition running 

Ps from about the middle 
of the base to a point a 
little on the right of 
the apex. Each of the 
chambers on the sides 

abet Ratena eres. tee of the septum is again 

incompletely divided 
transversely, into a thinner basal portion into which veins 
open, known as the auricle, and a thicker apical por- 
tion from which arteries arise, called the ventricle. The 
heart thus consists of a right auricle and ventricle and a 











EXTERIOR OF THE HEART. 200 


left auricle and ventricle, each auricle communicating by 
an awriculo-ventricular orifice with the ventricle on its own 
side, and thore is no direct communication whatever through 
the septum between the opposite sides of the heart. ‘lo 
get from one side to the uther the blood must leave the 


cs Sei 
ad 





Fro, 9—The heart and the ern blond-resset attached to It, seen from the 
side towards the sternum, left cavities and the vessels connected with 
them are colored red the right Ata, lott Adz aud Aa, the right 
auricular appendages veatricle ; Fs, loft ventricle ; Aa, 

aorta; Ab, innominate artery mon carotid artery: Sai, lnft 

elavian artery : ie of the pulmonney arteey. and’ fit nnd ies 
branobes to the rig lunges: <;. superior wena cava: ade and a, the 
Hight and left anon ‘pd ind ps, the right and left pulmonary veins; 

‘and cra, Use right and lefe coronary arteries. 










heart and pass through a set of capillaries, as may readily 
be seen by tracing the course of the vessels in Fig. 76. 

‘The Heart as seen from its Exterior. When the heart 
is viewed from the side turned towards the sternum (Fig. 
79) the two auricles, Add and As, are seen to bo separated _ 

















206 THE HUMAN BODY. 


by a deep grooye from the ventricles, Vd and Vs. A more 
shallow furrow runs between the ventricles and indicates 
the position of the internal longitudinal septum. On the 





Fra. The heart viewed from Its dorsal aspect. Atd, right auricle ; ef, 
Inferior vena cava; az, azygos vein ; Vo, eee vein, ‘The remaining letterr 
of reference have ihe kame signification as in Fig, 7¥. 
dorsal aspect of the heart (Fig. 80) similar points may be 
noted, and on one or other of the two figures the great 
vessels opening into the cavities of the heart may be seen. 
The pulmonary artery, P, arises from the right ventricle, 





INTERIOR OF THE HEART, 207 


and very soon divides into the right and left pulmonary 
arteries, Pd and Ps, which break up into smaller branches 
and enter the corresponding lungs. Opening into the 
right auricle are two great veins (see also Fig. 78), cs and 
ei, known respectively as the upper and lower vena cava, 
or “hollow” veins; so called by the older anatomists be- 
cause they are frequently found empty after death. Into 
the back of the right auricle opens also another vein, 
Ve, called the coronary vein or sinus, which brings back 
blood that has circulated in the walls of the heart it- 
self, Springing from the left ventricle, and appearing 
from beneath the pulmonary artery when the heart is 
looked at from the ventral side, is a great artery, the 
aorta, Aa. Tt forms an arch over the base of the heart 
and then rans down behind it at the back of the chest. 
From the convexity of the arch of the aorta several great 
branches are given off, Ssi, Cs, Ad; but before that, close 
to the heart, the aorta gives off two coronary arteries, 
branches of which are seen at ord and ers lying in the 
groove over the partition between the ventricles, and which 
carry to the substance of the organ that blood which comes 
back through the coronary sinus. Into the left auricle 
open two right and two left pulmonary veins, ps and pd, 
which are formed by the union of smaller veins proceeding 
from the lungs. 
ingram Fig. 78 from which the branches of the 
ar the heart have been omitted for the sake 
¢ connection of the various vessels with the 
chambers of the heart can be better seen. Opening into 
the right auricle are the superior and inferior vene cave 
rocecding from the right ventricle the 
P. Opening into the left auricle are 
the right and pulmonary veins { pd and ps) and spring- 
ing from the left ventricle the aorta, A. 

Tho Interior of the Heart, The communication of 
each wuricle with its ventricle is also represented diagram- 
matically in Fig. 78, and the valves which are present at 
those points and at the origin of the pulmonary artery and 
that of the aorta. Internally the auricles are for the most 








208 THE HUMAN BODY. 


part smooth, but from each a hollow pouch, the aurienlar 
appendage, projects over the base of the corresponding ven- 
tricle as seen at Adx and As in Figs. 79 and 80. These 
pouches have somewhat the shape of a dog’s ear and have 
given their namo to the whole auricle. Their interior is 
roughened by muscular elevations, covered by endocardium, 
known as the fleshy columns (columna carnee). On the 
inside of the ventricles (Fig. 81) similar fleshy columns are 
very prominent. 

The Auriculo-Ventricular Valves. These are known 
as right and deft, or as the frieuspid and mitral valves re- 
spectively, The mitral valve (Fig, 81) consists of two flaps 
of the endocardium fixed by their bases to the margins of 
auriculo-ventricular aperture and with their edges hanging 
down into the ventricle when the heart is empty. These 
unattached edges are not however free, but have fixed to 
them a number of stout connective-tiseue cords, the corda 
tendinew, which are fixed below to museular elevations, the 
papillary muscles, Mpin and Mpl, on the interior of the 
ventricle. The cords are Jong enough to let the valve flaps 
rise into a horizontal position and s0 close the opening be- 
tween auricle and ventricle which lies between them, and 
passes up behind the opened aorta, Sp, represented in the 
figure. The tricuspid vale is like the mitral but with 
three flaps instead of two, 

Somilunar Valves, These are six in number: three at 
the mouth of the aorta, Fig. 81, and three, quite like them, 
at the mouth of the pulmonary artery. Each is a strong 
erescentic pouch fixed by its more curved border, and with 
its free edge turned away from the heart. When the 
valves are in action these free edges meet across the vessel 
and prevent blood from flowing back into the ventricle. 
In the middle of the free border of each valve is a little 
cartilaginous nodule, the corpus Aranéfi, and on each side of 
this the edge of the valve is very thin and when it meets 
its neighbor doubles up against it and so secures the closure, 

The Arterial System. All the arteries of the Body 
arise either direetly or indirectly from the aorta or pulmo- 
nary artery and the great majority of them from the for- 














THE ARTERIES, 209 


mer yessel. The pulmonary artery only carries blood to 
the lungs to undergo exchanges with the air in them, after 
it has circulated through the Body generally, 

After making its arch the aorta continues back through 





Jia. The loft ventricle and the commencement 


the aorta laid open 
dom. Mp seo the papillary muscles, thetr uj hie xs are pron pe corto 


rooendng 40 the eds ofthe tape of the mitral valve, The open: 
ing ints the wuricle {es betwera thess flaps of the aorta are 
seen ité three pouch-like semallunar valves, 


the chest, giving off many branches on its way. Piercing 
the diaphragm it enters the abdomen and after supplying 
the parts in and around that cavity with branches, it ends 














210 THE HUMAN BODY. 


opposite the last lumbar vertebra by dividing into the right 
and left common iliac arteries, which carry blood to the 
lower limbs. We have then to consider the branches of the 
arch of the aorta, and those of the descending aorta, which 
latter is for convenience described by anatomists as consist- 
ing of the thoracic aorta, extending from the end of the 
arch to the diaphragm, and the abdominal aorta, extending 
from the diaphragm to the final subdivision of the vessel. 

Branches of the Arch of the Aorta. From this arise 
first the coronary arteries (crd and ers, Figs. 79 and 80) 
which spring close to the heart, just above two of the 
pouches of the semilunar valve, and carry blood into the 
substance of that organ. The remaining branches of the 
arch are three in number, and all arise from its convexity. 
The first is the innominate artery (Ab, Fig. 19), which is 
very short, immediately breaking up into the right sudcla- 
vian artery, and the right common carotid, Then comes 
the left common carotid, Cs, and finally the left sudclavian, 
Ssi. 

Each subclavian artery rans out to the arm on its own 
side and after giving off a ver/ebral artery (which rans up 
the neck tothe head in the vertebral canal of the transverse 
processes of the cervical vertebra), crosses the arm-pit and 
takes there the name of the azillary ariery. This con- 
tinues down the arm as the brachial artery, which, giving 
off branches on its way, runs to the front of the arm, and 
just below the elbow-joint divides into the radialand ulnar 
arteries, the lower ends of which are seen at Rand U in 
Fig. 77.* These supply the forearm and end in the hand 
by uniting to form an arch, from which branches are given 
off to the fingers. 

‘The common carotid arteries pass ont of the chestinto the 
neck, along which they ascend on the sides of the windpipe. 
Opposite the angle of the lower jaw each divides into an 
internal and external carotid artery, right or left as the 
case may be, The latter ends mainly in branches for the 
face, scalp, and salivary glands, one great subdivision of it 
with a tortuous course, the femporal artery, being often seen 
thin persons on the side of the brow, The in- 


*P, 202 











THE CAPILLARIES. 211 


ternal carotid artery enters the skull through an aperture 
in its base and supplies the brain, which it will be remem- 
bered also gets blood through the vertebral arteries. 

Branches of the Thoracic Aorta. ‘These are numerous 
but small. Some, the frtercostal arteries, run out between 
the ribs and supply the chest-walls; others, the bronchial 
arteries, carry blood to the lungs for their nourishment, 
that carried to them by the pulmonary arteries being 
brought there for another purpose; and a few other small 
branches are given to other neighboring parts. 

Branches of the Abdominal Aorta. ‘These are both 
large and numerous, supplying not only the wall of the 
posterior part of the trunk, but the important organs in the 
abdominal cavity. The larger are—the ealiac axis which 
supplies stomach, spleen, liver, and pancreas; the superior 
mesenteric artery which supplies a great part of the intes- 
tine; the renal arteries, one for each kidney; and finally 
the inferior mesenteric artery which supplies the rest of 
the intestine. Besides these the abdominal aorta gives off 
yery many smaller branches. 

Arteries of the Lower Limbs. Each common iliac di- 
vides into an tnéernal and external iliae artery. The 
former mainly ends in branches to parts lying in the pelvis, 
but the latter passes into the thighs and there takes the 
name of the femoral artery. At first this lies on the ven- 
tral aspect of the limb, but lower down passes back round 
the femur, and above the knee-joint, where it is called the 
popliteal artery, Givides into the anterior and posterior 
tibial arteries which supply the leg and foot. 

Tho Capillarios, As the arteries are followed from the 
heart their branches become smaller and smaller, and finally 
cannot be traced without the aid of a microscope. Ulti- 
mately they pass into the capillaries, the walls of which 
are simpler than those of the arteries, and which form 
very close networks in nearly all parts of the Body; their 
immense nnmber compensating for their smaller size, The 
average diameter of a capillary vessel is .016 mm. (riyq 
inch) so that only two or three blood corpuscles can pass 
through it abreast, and in many parts they are so close 












212 THE HUMAN BODY. 


that a pin’s point could not be inserted between two of 
them. It is while flowing in these delicate tubes that the 
blood does its nutritive work, the arteries being merely 
supply-tubes for the capillaries. 

The Veins, ‘The first veins arise from the capillary net- 
works in various organs, and like the last arteries are very 
small, They goon increase in size by union and so form 





Fro. 82.—A small portion of the capillary network as seen In the web 
when magnified about 35 diameters a, a small artery feeding the on : 
1, small veins carrying blood buck from the latter. 

larger and larger tranks. These in many places lie near or 
alongside the main artery of the part, but there are many 
more large veins just beneath the skin than there are large 
jes. This is especially tho case in the limbs, the main 
Which aro superficial and can in many persons be 





THE VEINS. 218 


seen as faint blue lines through the skin. Fig. 83 repre- 
sents the arm at the front of the elbow-joint after the 
skin and subcutaneous areolar tissue and fat have been re- 





Fro, $8-The superficial ring in front of theelbow joint. B*, tendon of Bieepe 
morve: 2&4 Berean pine shia? 2 ea a “a 
VTS 
moved. ‘The brachial artery, #, colored red, is seen lying 
tolerably deep and accompanied by two small veins (ven@ 
comites) which communicate by cross-branches, The great 








214 THE HUMAN Bopy. 


median nerve, 1, branch of the brachial plexus which 
supplies several muscles of the forearm and hand, the skin 
over a great part of the palm, and the three inner fingers, 
is seen alongside the artery. The larger veins of the part 
are seen to form a more superficial network, joined here 
and there, as for instance at *, by branches from deeper 
parts. Several small nerve-branches which supply the skin 
(2, 3, 4) areseen among these veins. It is from the veszel, 
cep, called the cephalic vein, just above the point where it 
crosses the median nerve, that surgeons usually bleed a 
patient. 

A great part of the blood of the lower limb is brought 
back by the long saphenous vein, which can be seen running 
beneath the skin from the inner side of the ankle to the 
top of the thigh, All the blood which leaves the heart by 
the aorta, except that flowing through the coronary arte- 
ries, is finally collected into the superior and inferior vena 
cave (cs and ci, Figs, 79 and 80), and poured into the 
right auricle. The jugular veins which ran down the 
neck, carrying back the blood which went out along the 
carotid arteries, unite below with the arm-vein (subclavian) 
to form on each side an innominate vein (Asi and Ade, 
Fig. 79) and the innominates unite to form the superior 
eaya. The coronary-artery blood after flowing through the 
capillaries of the heart itself, also returns to this auricle by 
the coronary veins. 

The Pulmonary Circulation. Through this the blood 
gets back to the left side of the heart and so into the aorta 
again. The pulmonary artery, dividing into branches for 
each long, ends in the capillaries of those organs. From 
these it is collected by the pulmonary veins which carry it 
back to the left auricle, whence it passes to the left ventricle 
to recommence its flow through the Body generally. 

Tho Course of the Blood. From what has been said it 
is clear that the movement of the blood is a circulation. 
Starting from any one chamber of the heart it will in time 
return to it; but to do this it must pass throngh at least 
two sets of capillaries; one of these is connected with the 
aorta and the other with the pulmonary artery, and in its 

* 





PORTAL CIRCULATION, 215 


circuit the blood returns to the heart twice. Leaving the 
left side it returns to the right, and leaving the right it 
returns to the left: and there is no road for it from one side 
of the heart to the other except through « capillary network. 
Moreover it always leaves from a ventricle through an 
artery, and returns to an auricle through a vein. 

There is then really only one circulation; but it is not 
uncommon to speak of two, the flow from the left side of 
the heart to the right, throngh the Body generally, being 
called the systemic circulation, and from the right to the 
left, through the lungs, the pulmonary circulation. But 
since after completing either of these alone the blood is not 
again atthe point from which it started, but is separated 
from it by the septum of the heart, neither is a “ circulation” 
in the proper sense of the word. 

‘The Portal Circulation. A certain portion of the blood 
which leaves the left ventricle of the heart through the 
sorta has to pass through three sets of capillaries before it 
can again return there. This is the portion which goes 
through the stomach, spleen, pancreas, and intestines. 
After traversing the capillaries of those organs it is col- 
lected into the portal vein which enters the liver, and 
breaking vp in it into finer and finer branches like an 
artery, ends in the capillaries of that organ, forming the 
second set which this blood passes through om its course, 
From these it is collected by the hepatic veins which pour 
it into the inferior vena cava, which carrying it to the right 
auricle, it has still to pass through the pulmonary capillaries 
to get buck to the left side of the heart. The portal vein 
is the only one in the Human Body which thus like an 
artery feeds a capillary network, and the flow from the 
stomach and intestines through the liver to the vena caya 
is often spoken of as the portal circulation. 

Diagram of the Circulation. Since the two halves of 
the heart are actually completely separated from one 
another by an impervious partition, although placed in 
proximity in the Body, we may conveniently represent the 
course of the blood as in the accompanying diagram (Fig. 
84) in which the right and left halves of the heart are rep- 











216 THE HUMAN BODY. 


resented at different points in the vaseular system. Such 
an arrangement makes it clear that the heart is really two 
pumps working side by side, and each engaged in forcing 
the blood to the other. Starting from the left auricle, la, 
and following the flow we trace it through the left ventri- 
cle and along. the branches of the 
aorta into the systemic capillaries, sc; 
from thence it passes back through 
the systemic veins, ve. Reaching 
the right auricle, ra, it is sent into 
the right ventricle, rv, and thence 
through the pulmonary artery, pa, 
to the lung capillaries, po, from 
which the pulmonary veins, pu, ear- 
ry it to the left auricle, which drives 
it into the left ventricle, /v, and this 
again into the aorta, 

Arterial and Venous Blood, The 
blood when flowing in the pulmo- 
nary capillaries gives up carbon diox- 
ide to the air and receives oxygen 
from it; and since its coloring mat- 
ter (hemoglobin) forms a scarlet 
of, the compound with oxygen, it flows to 
‘eyatorns, abo} 
ing that it forms. a single the left auricle in the pulmonary 
Seer veins of a bright red color, ‘This 
Wich are topresented saps: color it maintains until it reaches 
the systemic capillaries, but in these 
it loses much oxygen to the surround- 
pel ing tissues and gains much carbon 

dioxide from them. But the blood 

coloring matter which has lost its 
oxygen has a dark purple-black color, and since this un- 
oxidized or “reduced” hemoglobin is now in excess, the 
blood returns to the heart by the venw cavw of a dark 
purple-red color. This color it keeps until it reaches the 
lungs, when the reduced hemoglobin becomes again oxi- 
dized. The bright red blood, rich in oxygen and poor in 
carbon dioxide, is known as ‘arterial blood” and the dark 














STRUCTURE OF THE BILOOD-VESSELS. 217 


red as ‘* venous blood:” and it must be borne in mind that 
the terms have this peculiar technical meaning, and that 
the pulmonary veins contain arterial blood and the pulmo- 
nary arteries, venous blood; the change from arterial to 
venous taking place in the systemic capillaries, and from 
venous to arterial in the pulmonary capillaries. The 
chambers of the heart and the great vessels containing ar- 
terial blood are shaded red in Figs. 79 and 80. 

‘The Structure of the Arteries. A large artery can by 
careful dissection be separated into three coats; an futernal, 
middle and outer. ‘The internal coat tears readily across 
the long axis of the artery and consists of an inner lining 
of flattened nucleated cells, and of a variable number of 
layers composed of membranes or networks of elastic tissue, 
outside this. The middle coat is made up of alternating 
layers of clastic fibres and plain muscular tissue; the for- 
mer running for the most part longitudinally and the latter 
across tho long axis of the vessel. The outer coat is the 
toughest and strongest of all and is mainly made up of 
white fibrons connective tissue but contains a considerable 
amount of elastic tissue also. It gradually shades off into 
4 loose areolar tissue which forms the sheath of the artery 
or the tunica adventitia, and packs it between surrounding 
parts. The smaller arteries haye all the elastic cloments 
less developed. ‘T'he internal coat is consequently thinner, 
and the middle coat is made up mainly of involuntary mus- 
cular fibres. As a result the large arterios are highly elas- 
tic, the aorta being physically much like a piece of indian- 
rubber tubing, while the smaller arteries are highly con- 
tractile, in the physiological sense of the word. 

Structure of the Capillaries. In the smaller arteries 
the outer and middle coats gradually disappear, and the 
elastic Inyers of the inner coat also go. Finally, in the 
eapillaries the lining epithelium alone is left, with a 
more or less developed layer of connective-tissue corpuscles 
around it, representing the remnant of the tunica adven- 
titia. These vessels are thus extremely well adapted to al- 
low of filtration or diffusion taking place through their 
thin walla, 








218 THE HUMAN BODY. 


Structuro of the Veins. In these the same three pri- 
mary coats a3 in the arteries may be found: the inner and 
middle coats are less developed while the outer one remains 
thick, and is made up almost entirely of white fibrous tissue. 
Hence venous walls are much thinner than those of the 
corresponding arteries, and the veins collapze when empty 
while the stouter arteries remain open, But.the tenacity 
and toughness of their outer coats give the veins great 
strength. 

Except the pulmonary artery and the aorta, which pos- 
sess the semilunar yalves at their cardiac orifices, the 
arteries possess no valves. Many veins on the contrary have 
such, formed by semilunar pouches of the inner coat, at- 
tached by one margin and having that turned towards the 
heart free. These valves, sometimes single, oftener in 
pairs, and sometimes three at one level, permit blood to 
flow only towards the heart, for a current in that direction 
(as in the upper diagram, Fig. 85) presses the valve close 

against the side of the vessel and 

————_—Sos meets with no obstruction from it. 
¢_ >= = Should any back-flow be attempted, 

However: the current closes up the 
and bars its own passage as 
2 a a indicated in the lower figure. 

‘These valves are most numerous 

—Diagram to iw in snperficial veins and those of 


he 
trate the mode of action of 
Mewvalves of the reina C. the rnuscular parts. They are alent 


soltcl ihe vost’ now in the venm cavm and the portal 

and pulmonary veins. Usually the 
Yein is a little dilated opposite a valve and hence in parts 
where the valves are numerous gets a knotted look. On 
compressing the forearm s0 as to stop the flow in its sul)- 
entaneous veins and canse their dilatation, the points at 
which valves are placed can be recognized by their swollen 
nppearance. ‘I'bey are most frequently found where two 
veins communicate. 

















CHAPTER XV. 


THE WORKING OF THE HEART AND BLOOD- 
VESSELS. 


The Beat of the Heart. It is possible by methods known 
to physiologists to open the chest of a living narcotized 
animal, such as a rabbit, and see its heart at work, alter- 
nately contracting and diminishing the cavities within it 
and relaxing and expanding them. It is then observed 
that each beat commences at the mouths of the great veins; 
from there runs over the rest of the auricles, and then 
over the ventricles; the auricles commencing to dilate the 
moment the ventricles commence to contract. Having 
finished their contraction, the ventricles also commence to 
dilate and so for some time neither they nor the auricles 
are contracting, but the whole heart expanding. ‘The con- 
traction of any part of the heart is known as its systole 
and the relaxation as its diastole, and since the two sides 
of the heart work synchronously, the wuricles together and 
the ventricles together, we may describe a whole cardiac 
period” or ** heart-beat”’ us made up successively of awricu- 
lar systole, ventricular systole, and pause. This cycle ik 
repeated about seventy times a minute; and if the whole 
ime occupied by it be subdivided into 100 parts, about 
9 of these will be oceupied by the auricular systole, about 
30 by the ventricular systole, and 61 by the pause: 
daring more than half of life, therefore, the muscles of 
the heart are at rest. In the pause the heart if taken be- 
tween the finger and thumb feels soft and flabby but dur- 
ing the systole it (especially in its ventricular portion) be- 
comes hard and rigid. 

Change of Form of the Heart, During its systole the 











220 THE HUMAN BODY. 


heart becomes shorter and rounder, mainly from a change 
in the shape of the ventricles. A cross-section of the heart 
at the base of these latter during diastole would be ellipti- 
cal in outline, with its long diameter from right to left: 
during the systole it is more circular, the long axis of the 
ellipse becoming shortened while the dorso-yentral diameter 
romains little altered. At the same time the Jength of the 
ventricles is lessened, the apex of the heart approaching 
the base and becoming blunter and rounder. 

‘Tho Cardiac Impulse. The human heart lies with its 
apex touching the chest-wall between the fifth and sixth 
ribs on the left side of the breast-bone. At every beat a 
sort of tap, known as the ‘‘curdiac impulse” or ‘apex 
heat,” may be felt by the finger at that point. There is, 
however, no actual “ tapping” since the heart's apex never 
leaves the chest-wall. During the diastole the soft yentri- 
cles yield to the chest-wall where they touch it, but dur- 
ing the systole they become hard and tense and push it out 
a little between the ribs, and so cause the apex beat. Since 
the heart becomes shorter during the ventricular systole it 
might be supposed that at that time the apex would move 
up a little in the chest. This however is not the case, the 
ascent of the apex towards the base of the ventricles being 
compensated for by a movement of the whole heart in the 
opposite direction. If water be pumped into an elastic 
tube, already tolerably full, this will be distended not only 
transversely but longitudinally, This is what happens in 
the aorta: when the left ventricle contracts and pumps blood 
forcibly into it, the elastic artery is elongated as well as 
widened, and this lengthening of that limb of its arch at- 
tached to the heart pushes the latter down towards the dia- 
phragm, and compensates for the upward movement of the 
apex due to the shortening of the ventricles. Hence if the 
exposed living heart be watched it appears as if during the 
systole the base of the heart moved towards the tip, rather 
than the reverse. 

Events occurring within the Heart during a Cardiac 
Period. Let us commence ut the end of the ventricular 
systole. At this moment the semilunar valves at the orifices 











PHENOMENA OF THE HEARTS BEAT. 221 


of the aorta and the pulmonary artery are closed, so that no 
blood can flow back from those vessels, The whole heart, 
however, is soft and distensible and yields readily to blood 
flowing into it from the pulmonary yeins and the yenw 
cay; this passes on through the open mitral and tricuspid 
valves and fills up the dilating ventricles, as well as the 
auricles. As the ventricles fill, back currents are set np 
along their walls and these carry up the flaps of the valves 
so that by the end of the pause they are nearly closed. At 
this moment the auricles contract, and since this contrac- 
tion commences at and narrows tho mouths of the veins 
opening into them, and at the same time the blood in 
those vessels opposes some resistance to a back-flow into 
them, while the still flabby and dilating ventricles oppose 
much less resistance, the general result is that the contract 
ing auricles send blood mainly into the ventricles, and 
hardly any back into the veins. At the same time the in- 
creased direct current into the ventricles produces d greater 
back current on the sides, which, as the auricles cease their 
contraction and the filled ventricles become tense and press 
on the blood inside them, completely close the auriculo- 
ventricular valves. That this increased filling of the yen- 
tricles, due to auricular contractions, will close the valves is 
seen easily in a sheep's heart. If the auricles be carefully 
eut away from this so a8 to expose the mitral and tricuspid 
valves, and water be then poured from a little height into 
the ventricles, it will be seen that as these cavities are filled 
the yalve-flaps are floated up and close the orifices. 

‘The auricular contraction now ceases and the ventricular 
commences, ‘The blood in each ventricle is imprisoned 
between the anriculo-ventricular valves behind and the 
semilunar valves in front. The former cannot yield on 
account of the cordm tendinew fixed to their edges: the 
semilanar valves, on the other hand, can open outwards from 
the ventricle and let the blood pass on, but they are kept 
tightly shut by the pressure of the blood on their other 
sides, just as the lock-gates of a canal are by the pressure of 
the water on them. Jn order toopen the canal-gutes water 
is let in or outof the lock until it stands at the same level 

















222 THE HUMAN BODY. 


on each side of them; but of course they might be forced 
open without this by applying sufficient power to overcome 
the higher water pressure on one side, It is in this latter 
way that the semilunar valves are opened. The contracting 
ventricle tightens its grip on the blood inside it and becomes 
rigid to the touch, As it squeezes Harder and harder, at 
last the pressure on the blood in it becomes greater than 
the pressure exerted on the other side of the valves by the 
blood in the arteries, the flaps are pushed open, and the 
blood begins to pass out: the ventricle continues its con- 
traction until it has obliterated its cavity and completely 
emptied itself. Then it commences to relax and blood 
immediately to flow back into it from the highly stretched 
arteries. This back current, however, catches the pockets 
of the semilunar valves, drives them back and closes the 
valve so a3 to form an impassable barrier; and so the blood 
which has been forced out of cither ventricle cannot flow 
directly back into it. 

Use of the Papillary Muscles, In order that the con- 
tructing ventricles may not force blood back into the 
auricles it is easential that the flaps of the mitral and 
tricuspid valves be maintained horizontally across the open- 
ings which they close, and be not pushed back into the 
auricles. At the commencement of the ventricular sys- 
tole this is provided for by the cordw tendinew, which are 
of such a length as to keep the edges of the flaps in appo- 
sition, a position which is farther secured by the fact that 
each set of corde tendince (Fig. 81*) radiating from a 
point in the ventricle, is not attached around the edges of 
one flap but on the contiguous edges of two flaps, and so 
tends to pull them together. But as the contracting ven- 
tricles shorten, the cords tendines, if directly fixed to 
their interior, would be slackened and the valve-flaps 
pushed up into the auricle. The little papillary muscles 
prevent this. Shortening as the ventricular systole proceeds, 
they keep the cords taut and the valyes closed. 

Sounds of the Heart. If the car be placed on the chest 
over the region of the heart daring life, two distingnish- 
able sounds will be heard during each cardiac cycle. They 

are known respectively as the first and second sounds of the 


~*P, 200, 








EVENTS tN A CARDIAO CYCLE. 223 


heart. The first is of lower pitch and lasts longer than the 
second and sharper sound: vocally their character may be 
tolerably imitated by the words 74d), diip. The cause of 
the second sound is the closure, or as one might say the 
*‘olicking up,” of the semilunar valves, since it occurs at 
the moment of their closure and ceases if they be hooked 
back in a living animal. The origin of the first sound is 
still uncertain: it takes place during the ventricular systole 
and is probably due to vibrations of the tense ventricular 
wall at that time. It is not due, as has been supposed, to 
the auriculo-ventricular valves, since it may still be heard 
in a beating heart empty of blood, and in which there could 
be no closure or tension of those valves. In various forms 
of heart disease these sounds are modified or cloaked by 
additional ‘* murmurs” which arise when the cardiac orifices 
are roughened or narrowed or dilated, or the valves ineffi- 
cient. By paying attention to the character of the new 
sound then heard, the exact period in the cardiac cycle at 
which it occurs, and the region of the chest-wall at which it 
is heard most distinctly, the physician can often get impor- 
tant information as to its cause. 

of the Evonts of a Cardiac Cycle. In the 
following table the phenomena of the heart’s beat are rep- 
resented with reference to the changes of form which are 
seen in an exposed working heart. Events in the same 
Yertical column occur simultaneously; on the same horizon- 
tal line, from left to right, successively. 





Auriqujar ys | ment ce en | Ventriottar 
its | cuit ye 


ceamsin ot 
see | Seat) em 





Contract Ditating and Dilating and! Dilating | Davin 
ona ‘filling. ‘ain and Alling. | and filing 
| Dilak fating seal ‘Contracting. | Contracting Dilating. | 7 | Ditating 


“and Alling. 
exnptying. 


Sa | ees | ES 


+1] Apox beat. 








224 THE HUMAN BODY. 





Punction of the Auricles. The ventricles haye to do 
the work of pumping the blood through the blood-vessels. | 
Accordingly their walls are far thicker and more muscular 
than those of the auricles; and the left ventricle, which has 
to force the blood over the Body generally, i stouter than 
the right, which has only to send blood around the com- 
paratively short pulmonarycircuit. The circulation of the 
blood is in fact maintained by the ventricles, and we 
have to inquire what is the use of the auricles. Not un- 
frequently the heart's action is described as if the auricles 
first filled with blood and then contracted and filled the 
yentricles; and then the latter contracted and drove the 

e blood into the arteries. From the acconnt given above, 
however, it will be seen that the events are not accurately 
so represented, but that during all the pause blood flows 
on through the auricles into the ventricles, which latter 
are already nearly full when the auricles contract; this con- 
traction merely completing their filling and finishing the 
closure of the auriculo-ventricular valves, The real use of 
the auricles is to afford a reservoir into which the veins may 
empty while the comparatively long-lasting ventricular 
contraction is taking place: they also largely control the 
amount of work done by the heart. 

If the heart consisted of the ventricles only, with valves 
at the points of entry and exitof the blood, the circulation 
could be maintained. During diastole the ventricle would 
fill from the veins, and daring systole empty into the ar- 
teries. But in order to accomplish this, during the systole 
the valves at the point of entry must be closed, or the ven- 
tricle would empty itself into the veins as well as into the 
arteries; and this closure would necessitate a great loss of 
time which might be utilized for feeding the pump. 
‘This is avoided by the auricles, which are really reser- 
yoirs at the end of the venous system collecting blood 
when the ventricular pump is at work. When the ven- 
tricles relax, the blood entering the auricles flows on 
into them: but previously, during the 3%’; of the cardiac 
cyele occupied by the ventricular systole, the auricles 
have accumulated blood, and when they at Jast con- 








FUNCTION OF THE AURICLES. 225 


tract they send on into the ventricles this accumulation. 
Even were the flow from the veins stopped during the 
auricular contraction this would be of comparatively little 
consequence, since that event oceupies so brief a time. 
But, although no doubt somewhat lessened, the emptying 
of the veins into the heart does not seem to be, in health, 
stopped while the auricle is contracting. For at that mo- 
ment the ventricle is relaxing and receives the blood from 
the auricles under a less pressure than it enters the latter 
from the veins. The heart in fact consists of a couple of 
** feed-pumps”—the auricles—and a couple of ‘foree- 
pumps”—the ventricles; and so wonderfully perfect is the 
mechanism that the snpply to the feed-pumps is never 
stopped. The auricles are never empty, being supplied all 
the time of their contraction, which is never so great as to 
obliterate their cavities; while the ventricles contain no 
blood at the end of their systole. 

The auricles also govern toa certain extent the amount 
of work done by the ventricles. These latter contract with 
more than sufficient force to completely drive out all the 
blood contained in them. If the auricles contract more 
powerfully and empty themselves more completely at any 
given timo, the ventricles will contain more blood at the 
commencement of their systole, and have pumped out more 
at its end. Now as we shall sce in Chapter XVIL, the 
contraction of the auricles is under the control of the 
nervous system; and through the auricles the whole work 
of the heart. In fact the ventricles represent the brute 
force concerned in maintaining the circulation, while 
\he auricles are part of a highly developed co-ordinating 
mechanism, by which the rate of the circulation is governed 
according to the needs of the whole Body at the time. 

The Work Done by the Heart, This can be calculated 
with approximate correctness. At each systole each yen- 
tricle sends out the same quantity of blood—abont 180 
grams (6.3 ounces); the pressure exerted by the blood 
in the aorta against the semilunar yalves and which the 
yentriclo has to overcome is about that which would be ex- 
erled on the same surface by 4 column of mercury 200 











226 THE HUMAN BObY. 


millimeters (8 inches) high. The left ventricle therefore 
drives out, seventy times in a minute, 180 grams (6.3 
ounces) of blood against this pressure. Since the specific 
gravity of mercury is 12.5 and that of blood may for prac- 
tical purposes be taken as 1, the work of each stroke of the 
ventricle is equivalent to raising 180 grams (6.3 ounces) 
of blood 200 x 12.5 = 2500 millim. (8.2 feet); or one 
gram 450 meters (one ounce 51.66 feet); or one kilo- 
gram 0.45 meters (one Ib. 3.23 feet). Work is measured 
by the amount of energy needed to raise a definite weight 
& given distance against gravity at the earth's surface, the 

t, called a kilogrammeter, being either that necessary to 
raise one kilogram one meter, or, culled a foot-pound, that 
necessary to raisé one pound one foot. Expressed thus the 
work of the left ventricle in one minute, when the heart’: 
rate is seventy strokes in that time, is 0.45 x 70 = 31.50 
kilogrammeters (3.23 X 70 = 226.1 foot-pounds); in one 
hour it is 1.50 x 60 = 1890 kilogrammeters (220.1 x 60 
= 15,566 foot pounds); and in twenty-four hours 1890 x 24 
= 45,360 kilogrammeters (325,584 foot-pounds). The pres- 
sure in the pulmonary artery against which the right ventricle 
works is about } of that in the aorta; hence this ventricle 
in twenty-four hours will do one third as much work as the 
jeft, or 15,120 kilogrammeters (108,528 foot pounds) and 
adding this to the amount done by the left, we get as the 
total work of the ventricles in a day the immense amount 
of 60,480 kilogrammeters (434,112 foot-pounds). If a man 
weighing 75 kilograms (165 Ibs.) climbed up a mountain 
806 meters (2644 feet) high his skeletal muscles would 
probably be greatly fatigued at the end of the ascent, and 
yet in lifting his Body that height they would only have 
performed the amount of work that the ventricles of the 
heart do daily without fatigue. 

‘The Flow of the Blood Outside the Heart. The blood 
leaves the heart intermittently and not in a regular stream, 
a quantity being forced out at each systole of the yentri- 
cles: before it reaches the capillaries, however, this rhythmic 
movement is transformed into a steady flow as may readily 
be seen by examining under the microscope thin traus- 





BLOOD-FLOW AS SEEN WITH THE MICROSCOPE. 227 


parent parts of various animals, as the web of a frog’s foot, 
4 mouse’s ear, or the tail of a small fish. In consequence 
of the steadiness with which the capillaries supply the veins 
the flow in these is also unaffected, directly, by each beat of 
the heart; if a vein be cut the blood wells out uniformly, 
while # cut artery spurts out not only with much moro 
force, but in jets which are much more powerful at regu- 
lar intervals corresponding with the systoles of the yen- 
tricles. 

Tho Circulation of the Blood as Seen in the Frog’s Wob. 
There is no more fascinating or instructive phenomenon 
than the circulation of the blood as seen with the micro- 
scope in the thin membrane between the toes of a frog’s 
hind limb, Upon focusing beneath the epidermis a net- 
work of minute arteries, veins and capillaries, with the blood 
flowing through them, comes into view (Fig. 82%). The 
arteries, a, are readily recognized by the fact that the flow in 
them is fastest and from larger to smaller branches. The 
latter are seen ending in capillaries, which form networks, 
the channels of which are all nearly equal in size, While 
im the veins arising from the capillary the flow is from 
smaller to larger trunks, and slower than in the arteries 
but faster than in the capillaries. 

‘The reason of the slower flow of the capillaries is that 
their united area 1s considerably greater than that of the 
arteries supplying them, 30 that the same quantity of blood 
flowing through them in a given time, has a wider channel 
to flow im and moves more slowly. The area of the veins 
is smaller than that of the capillaries but greater than 
that of the arteries, and hence the rate of movement in them 
is also. intermediate. Almost always when an artery 
divides, the urea of its branches is greater than that of the 
main trunk, and so the arterial current becomes slower and 
slower from the heart onwards. In the veins on the other 
hand, thearca of a trank formed by the union of two or 
more branches is less than that of the branches together, 
and the flow becomes quicker and quicker towards the 
heart. But even at the heart the united cross-sections 
of the yeins entering the auricles is greater than that of 


*P. 213. 


. 








228 THE HUMAN BODY. 


the arteries leaving the ventricles, so that, since as much 
blood returns to the heart in a given time as leaves it, the 
rate of the current in the pulmonary veins and the ven 
cave is leas than in the pulmonary artery and aorta, We 
may represent the vascular system as a double cone, widening 
from the ventricles to the capillaries and narrowing from 
the latter to the auricles. Just as water foreed in at a 
narrow end of this would flow quickest there and slowest 
at the widest part, go the blood flows quickest in the aorta 
and slowest in the capillaries, which form together a much 
wider channel. 

‘The Axial Current and the Inert Layer. If « small 
artery in the frog’s web be closely examined it will be seen 
that the rate of flow is not the same in all parts of it. In 
the centre isa very rapid current carrying along all the red 
corpuscles and known as the axial stream, while near the 
wall of the vessel the flow is much slower, as indicated by the 
rate at which the pale blood corpuscles are carried along in 
it. This isa purely physical phenomenon. If any liquid be 
forcibly driven through a fine tube which it wets, water 
for instance through a glass tube, the outermost layer of the 
liquid will remain motionless in contact with the tube; 
the next layer of molecules will move faster, the next 
faster still; and so on until a very rapid current is found 
in the centre. If solid bodies, as powdered scaling-wax, 
he suspended in the water, these will all be carried on 
in the central faster current or axial stream, just as the 
red corpuscles are in the artery. ‘The white corpuscles, on 
account of their power of executing independent ameboid 
movements and their consequent irregular form, get fre- 
quently pushed ont of the axial current, so that many of 
them are found in the inert layer. 

Internal Friction. It follows from the above-stated 
facts that there is no noticeable friction between the blood 
and the lining of the vessel through which it flows: since 
the outermost blood Jayer in contact with the wall of the 
vessel is almost motionless, But there is very great fric- 
tion between the different concentric layers of the liquid, 
since each of them is moving at a different rate from those 


THE CAPILLARY CIRCULATION. 229 


in contact with it on each side. This form of friction is 
known in hydro-dynamics as “ internal friction” and it is 
of great importance in the ciroulation of the blood. In- 
ternal friction increases very fast as the calibre of the 
tube throngh which the liquid flows diminishes: so that 
with the same rate of flow it is disproportionately much 
greater in a small tube than in a larger one. Hence a 
given quantity of liquid forced in @ minute through one 
large tube, would experience much less resistance from in- 
ternal friction than if sent in the same-time through four 
or five smaller tubes, the anited transverse sections of which 
were together equal to that of the single larger one. In 
the blood-vessels the increased total area, and consequently 
slower flow, in the smaller channels partly counteracts this 
inerease of internal friction, but only to a comparatively 
slight extent; so that the internal friction, and conse- 
quently the resistance to the blood-flow, is far greater in the 
capillaries than in the small arteries, and in the small ar- 
teries than in the large ones. Practically we may regard 
the arteries a3 tubes ending in a sponge: the united areas 
of all the channels in the latter might be considerably 
larger than that of the supplying tubes, but the friction to 
be overcome in the flow through them would be much 
greater. 

The Conversion of the Intermittent into a Continuous 
Flow. Since the heart sends blood into the aorta inter- 
mittently, we have still to inquire how it is that the flowin 
the capillaries is continuous, In the larger arteries it is 
not, since we can feel them dilating as the “pulse,” by ap- 
plying the finger over the radial artery at the wrist, or the 
temporal artery on the side of the brow. 

The first explanation which suggests itself is that since 
the capacity of the blood-vessels increases from the heart 
to the capillaries, an acceleration of the flow during the 
ventricular contraction which might be very manifest in 
the vessels near the heart would become less and leas obvi- 
ous in the more distant vessels. But if this were so, then 
when the blood was collected again from the wide capillary 
sponge into the great veins near the heart, which together 





ure very little bigger than the aorta, we ought to 
pulse, but we do not: the venons pulse which sometimes 
occurs having quite a different cause, being due to a back- 
flow from the auricles, or a checking of the on-flow into — 
them, during the cardiac systole, The rhythmic flow 
eaused by the heart is therefore not merely cloaked in the — 
small arteries and capillaries but abolished in them. . 
We can, however, readily contrive conditions outside the 
Body under which an intermittent supply is transformed 
into a continuons flow. Sup- 
pose we have two vessels, A 
and # (Fig. 86), containing 
_ Water and connected below in 
two ways; through the tube 
@ on which there is a pump 
provided with valves so that 
it can only drive liquid from 
A to B, and through 6, 
which may be left wide open 
or narrowed by the clamp e, 
at will. If the apparatus be 
left at rest the water will lie at the same level, d, in each 
vesssel. If now we work the pump, at each stroke a cer- 
tain amount of water will be conveyed from A to B, and 
as a result of the lowering of the level of liquid in 4 and 
its rise in B, there will be immediately a return flow from 
B to A throngh the tube 4 A, in these circumstances, 
would represent the venous system, from which the heart 
constantly takes blood to pump it into #, representing the 
arterial system; and 6 would represent the capillary vessels 
through which the return flow takes place: but, so far, we 
should have as intermittent a flow through the capillaries, 
6, as through the heart-pump, a. Now imagine 6 to be 
narrowed at one point so as to oppose tance to the 
back-flow, while the pump goes on working ste; 
sult will be an accumulation of water in B, anc 
level in A. But the more the difference 
vessels increases, the greater is the force 
water back through } to A, and more will 





CAUSE OF STEADY CAPILLARY BLOOD-FLOW. 231 


the greater difference of pressure, in a given time, until at 
last, when the water in B has reached a certain level, a’, 
and that in A has correspondingly fallen to @", the current 
through 6 will carry back in one minate just so much water 
as the pump sends the other way, and this back-flow will 
be nearly constant; it will not depend directly upon the 
strokes of the pump but upon the head of water acenmu- 
lated in B; which head of water will, it is true, be slightly 
increased at each stroke of the pump, but the increase will 
be very small compared with the whole driving force; and 
its influence will be inappreciable. We thus gain the idea 
that an incomplete impediment to the flow from the ar- 
teries to the veins (from #to A in the diagram), such as is 
afforded by internal friction in the capillaries, may bring 
about conditions which will lead to a steady flow through 
the latter vessels, 

But in the arterial system there can be no accumulation 
of blood at « higher level than that in the veins, such as is 
supposed in the above apparatus: and we must next con- 
sider if the “head of water” can be replaced by some other 
form of driving force. It is in fact replaced by the elas- 
ticity of the large arteries. Suppose an elastic bag in- 
stead of the vessel B connected with the pump, “a.” If 
there be no resistance to the back-flow the current through 
4 will be discontinuous, But if resistance be interposed, 
then the elastic bag will become distended, since the pamp 
sends in a given time more liquid into it than it passes 
back through 6. But the more it becomes distended the 
more will the bag squeeze the liquid inside and the faster 
will it send that back to A, until at last its squeeze is so pow- 
erful that in a minute or any other unit of time it sends 
buck into A as much as it receives, henceforth the 
twek-flow through 4 will be practically constant, being im- 
mediately dependent upon the elastic reaction of the bag; 
and only indirectly upon the action of the pump which 
keeps it distended. Such a state of things represents very 
closely the phenomena occurring in the blood-vessels, 
The highly elastic large arteries are kept stretched with 
blood by the heart; and the reaction of their elastic walls, 





ily squeezing on the blood in them, forces it co 

ously through the small arteries and capillaries, Y 
steady flow in the latter depends thus on two factors: first: 
the elasticity of the large arteries; and secondly the re- 
sistance to their emptying, dependent upon internal frietion 
in the small arteries and the capillaries, which calls into 
play the elasticity of the large vessels, Were the capillary 
resistance or the arterial elasticity absent the blood-flow in 
the capillaries would be rhythmic. 





CHAPTER XVI. 


ARTERIAL PRESSURE. THE PULSE. 


Weber’s Schema, It is clear from the statements made 
in the last chapter that itis the pressure exerted by the elas- 
tic arteries upon the blood inside them which keeps up the 
flow through the capillaries, the heart serving to keep the 
big arteries tightly filled and go to call the elastic reaction of 
their walls into play. The whole cireulation depends 
primarily of course upon the beat of the heart, but this 
only indirectly governs the capillary flow, and since the 
latter is the aim of the whole vascular apparatus it is of 
great importance to know all about arterial pressure; not 
only how great it is on the average but how it is altered in 
different vessels in various circumstances so as to make the 
flow through the capillaries of a given part the greater or 
Jess according to circumstances; for, as blushing and pallor 
of the face (which frequently oceur without any change in 
the skin elsewhere) prove, the quantity of blood flowing 
through a given part is not always the same, nor is it 
always increased or diminished in all parts of the Body at 
the same time. Most of what we know about arterial pres- 
eure has been ascertained by experiments made upon the 
lower animals, from which deductions are then made con- 
cerning what happens in man, since anatomy shows that the 
circulatory organs are arranged upon the same plan in all 
the mammalia. A great deal can, however, be learnt by 
studying the flow of liquids through ordinary clastic tubes. 
Suppose we have a set of such (Fig. 87) supplied at one 
point with a pump, ¢, possessing valves of entry and exit 
which open only in the direction indicated by the arrows, 
and that the whole system is slightly overfilled with liquid so 








that its elastic walls are slightly stretched. These will in. 
consequence press upon the liquid inside them and the 
umount of this pressure will be indicated by the gauges: 
s0 long as the pumpis at rest it will be the same everywhere 
(and therefore equal in the gauges on B and A), since 
liquid in a set of horizontal tubes communicating freely, 
as these do at D, always distributes itself so that the 
pressure upon it is everywhere the same, Let the pump 
¢ now contract once, and then dilate: during the contrac- 
tion it will empty itself into B and during the dilatation fill 
itself from A, Consequently the pressure in B, indicated 
by the gauge 2, will rise and that in A will fall. But very 
rapidly the liquid will redistribute itself from B to A 
through J, until it again exists everywhere under the same 





Fio, 87.—Dingram of Weber's Schema, 


pressure. Every time the pump works there will occur a 
similar serics of phenomena, and there will be a disturbance 
of equilibrium causing a wave to flow round the tubing; 
but there will be no steady maintenance of a pressure on 
the side B greater than that in A. Now let the upper 
tube D be closed ao that the liquid to get from B to A must 
flow through the narrow lower tubes D, which oppose con- 
siderable resistance to its passage on account of their fre- 
quent branchings and the great internal friction in them; 
then if the pump works frequently enough there will be 
produced and maintained in # a pressure considerably higher 
than that in A, which may even become negative. If, for 


i 


WEBER'S SCHEMA. 235 


example, the pump works 60 times a minute and at cach 
stroke takes 180 cubic centimeters of liquid (6 ounces) from 
A and drives it into B, the quantity sent in at the first 
stroke will not (on account of the resistance to its flow 
offered by the small branched tubes), have all got back into 
A before the next stroke takes place, sending 180 more 
cubic’ centimeters (6 oz.) into B. Consequently at each 
stroke # will become more and more distended and A more 
and more emptied, and the gauge x will indicate » much 
higher pressure than thaton A. As B is more stretched, 
however, it squeezes harder upon its contents, until at last 
a time comes when this squeeze is powerful enough to force 
through the small tubes just 180 cubic centimeters (6 oz.) in 
asocond. Then farther accumulation in B ceases, The 
pump sends into it 10,800 cubic centimeters (360 ounces) 
ina minute at one end and if squeezes ont exactly that 
amount in the same time from its other end; and so long 
us the pump works steadily the pressure in 8 will not rise, 
nor thatin A fall, any more. But under such circumstances 
the flow through the small tubes will be nearly constant 
since it depends upon the difference in pressure prevailing 
between B and A, and only indirectly upon the pump 
which serves simply to keep the pressure high in # and 
low in A. At each stroke of the pump it is true there will 
be a slight increase of pressure in B due to the fresh 180 
cub, cent. (6 oz.) forced into it, but this increase will be 
butasmall fraction of the total pressure and so have but an 
insignificant influence upon the rate of flow through the 
small connecting tubes. 

Arterial Pressure. The condition of things just de- 
acribed represents very closely the phenomena presented in 
the blood-vasculur system, in which the ventricles of the 
heart, with their auriculo-ventrieular and semilunar valves, 
represent the pump, the smallest arteries and the capil- 
laries the resistance at D, the large arteries the elastic 
tube #, and the veins the tube A. The ventricles con- 
stantly receiving blood through the auricles from the veins, 
send it into the arteries, which find a difficulty in emptying 
themselves through the capillaries, and so blood accumu- 








bd THE HUMAN BODY. 


Iates in them until the elastic resetion of the stretched ar- 
teries iz able to squeeze in a minute through the capillaries 
just 2 much blood as the left ventricle pamps into the 
sorta, and the right into the pulmonary artery, in the same 
time. Accordingly in a living animal s 

connected with an artery shows a much higher pressure 
than one connected with a vein, and this persistent differ- 
ence of pressure, only increased by u small fraction of the 
whole st exch heart-beat, keeps up a steady flow from the 
arteriea to the veins. The heart keeps the arteries stretched 
and the stretched arteries maintain the flow through the 
capillaries, and the constancy of the current in these de- 
penda on two factors: (1) the resistance experienced by the 
blood in ita flow from the ventricles to the yeins, and (2) 
the elasticity of the larger arteries which allows the blood 
to accumulate in them under a high pressure, in conse- 
quence of this resistance. 

The Arterial Preasure. This cannot be directly meas- 
ured with accuracy in man, but from measurements made 
on other animals it is calculated that in the human aorta 
ite avorage is equal to that of a column of mereury 200 
millimeters (8 inches) high. During the systole it rises 
about 5 millimeters (} inch) above this and during the pause 
falls the same amount below it. The pressure in the venm 
cay on the other hand is often negative, the blood being, 
to wee ordinary language, often “sucked” out of them into 
the heart, and it rarely rises above 5 millimeters ({ inch) of 
mercury except under conditions (such as powerful mus- 
cular effort accompanied by holding the breath) which 
foree blood on into the venw cave and, by impeding the 
pulmonary circulation, interfere with the emptying of the 
right auricle, Hence to maintain the flow from the aorta 
to the vena cava we have un average difference of pressure 
equal to 200 — 5 = 195 millimeters (7 inches) of mereury, 
rising to 205 — 5 = 200 mm. (8 inches) during the cardiac 
systole and falling to 195 — 190 mm. (7 inches) dur- 
ing the pause; but the slight alterations, only about gy of 
the wholo difference of sortie and vena cava pressures which 
maintain the blood-flow, are too slight to cause appreciable 














changes in the rate of the current in the capillaries. The 
pressure on the blood in the pulmonary artery is about } of 
that in the aorta, 

Since the blood flows from the aorta to its branches and 
from these to the capillaries and thence to the veins, and 
liquids in a set of continuous tubes flow from points of 
greater to those of less pressure, it is clear that the blood- 
pressure must constantly diminish from the aorta to the 
right auricle; and similarly from the pulmonary artery to 
the left auricle, At any point in fact the pressure is pro- 
portionate to the resistance in front, and since the farther 
the blood has gone the less of this, due to impediments at 
branchings and to internal friction, it has to overcome in 
finishing its round, the pressure on the blood always di- 
minishes as we follow it from the aorta to the ven» cave. 
Tn the larger arteries the fall of pressure is gradual and 
small, since the amount of resistance met with in the 
flow through them is but little. In the small arteries and 
capillaries the resistance passed by is (on account of the 
great internal friction due to their small calibre) very great, 
and consequently the full of pressure between the medium- 
sized arteries and the veins is rapid and considerable, 

Modifications of Arterial Pressure by Changes in the 
Rate of the Heart's Beat. A little consideration will make 
it clear that the pressure prevailing at any time in a given 
artery depends on two things—the rate at which the vessel 
is filled, #.¢, upon the amount of work done by the heart; and 
the ease or difficulty with which it is emptied, that is upon 
the resistance in front. Returning to the system of elus- 
tie tubes with a pump represented in Fig. 87, let us sup- 
pose the pamp to be driving as before 10,800 cub, cent. 
(360 oz.) per minute into the tubes # and that these latter 
are so distended that they drive out just that quantity in 
the same time. Under such conditions the pressure at any 
given point in B will remain constant, apart from the small 
variations dependent upon each stroke of the pump. 
Now, however, let the latter, while still sending in 180 cub. 
cent. (6 oz.) at each stroke, work 80 instead of 60 times a 
minute and so send in that time 180 x 80 = 14,400 eub. 





288 THE HUMAN BODY. 


cent, (480 oz.) instead of the former quantity. ‘This will 
lead to an accumulation in B, since its squeeze is only suf- 
ficient, against the resistance opposed to it, to send out 10,- 
800 cub, cent. (360 oz.) ina minute, B consequently will 
become more stretched and the pressure in it willrise. As 
this takes place, however, it will squeeze more powerfully 
on its contents until at last its distension is such that its 
elasticity is able to force out in « minute through the emall 
tubes D, 14,400 cub, cent. (4800z.). Thenceforth, so long 
as the pump beats with the sume force and at the same rate 
and the peripheral resistance remains the same, the mean 
jressure in B will neither rise nor fall—B sending into A 
in a minute as much as ¢ takes from it, and we would haye 
a steady condition of things with a higher mean pressure 
in B than before, 

On the other hand if the pump begins to work more 
slowly while the resistance remains the same, it is clear that 
the mean pressure in # will fall. If, for example, the pump 
works only forty times a minute and so sends in that time 
180 xX 40 = 7200 cub. cent. (240 oz.) into B, which is so 
stretched that it is squeezing out 10,800 cub, cent. (360 
oz.) in that time, it is clear that B will gradually empty 
itself and its walls become less stretched and the pressure 
in it fall, As this takes place, however, it will force loss 
liquid in a minute through the small tubes, until at last a 
pressure is reached at which the squeeze of 2 only sends 
out 7200 cub, cent, (240 oz.) in a minute; and then the 
fall of pressure will cease and a steady one will be main- 
tained, but lower than before. 

Applying the same reasoning to the vascular system we 
see that (when the peripheral resistance remains unaltered), 
if the heart’s force remains the same but its rate increases, 
urterial pressure will rise to a new level, while a slowing of 
the heart's beat will bring about a fall of pressure. 

Modifications of Arterial Pressure Dependent on 

in the Force of the Heart’s Beat. Returning 
again to Fig. 87; suppose that while the rate of the pump 
remains the same, its power alters so that each time it 
sends 200 cub, cent. (6.6 oz.) instead of 180 (6 oz.) and so in 





OHANGES IN ARTERIAL PRESSURE. 239 


a minute 12,000 cub. cent. (396 oz.) instead of 10,800 (360 
oz,)—the quantity which B is stretched enough to squeeze 
out inthat time. Water will in consequence accumulate in 
B until it becomes stretched enough to squeeze out 12,000 
eub. cent, (306 oz.) in a minute, and then a steady pressure 
at a new and higher level will be maintained. On the 
other hand if the pump, still beating sixty times a minute, 
works more feebly so as to send outonly 160 cub. cent. (5.6 
oz.) at each stroke, then B, squeezing out at first more 
than it receives in a given time, will gradually empty 
itself until it only presses hard enough upon its contents 
to force 160 X 60 = 9600 cub. cent. (836 oz.) out in a 
tainate. 

Similarly, if while the resistance in the small arteries 
and capillaries remains the same and also the heart's rate, 
the power of the stroke of the latter alters, so that at each 
beat it sends more blood out than previously, then arterial 
pressure will rise; while if the heart beats more feebly it 
will fall. 

Modifications of Arterial Prossuro by Changes in the 
Peripheral Resistance. Let the pump ¢ in Pig. 87 still 
work steadily sending 10,800 cub, cent. (360 oz.) per min- 
ute into B and the resistance increase, it is clear arterial 
pressure must rise, For B is only stretched enough to 
squeeze out in a minute the above quantity of liquid against 
the original resistance and cannot at first send out that 
quantity against the greater. Liquid will consequently ac- 
cumulate in it until at last it becomes stretched enough to 
send out 10,800 enb. cent.'(360 cubic oz.) in & minute 
through the small tubes, in spite of the greater resistance 
to be overcome. A new mean pressure at a higher level 
will then be established. If on the contrary the resistance 
diminishes while the pump’s work remains the same, then 
# will at first squeeze out in a minute more than it receives, 
until finally its elastic pressure is reduced to the point at 
which its receipts and Josses balance, and a new and lower 
mean pressure will be established in B. 

So in the vascular system increase of the peripheral re- 
sistance by narrowing of the emul! arteries will increase ar- 





240 THE HUMAN BODY. 





terial pressure in all parts nearer the heart, while dilatation 
of the small arteries will have the contrary effect. 

We find then that arterial pressure at any’ 
moment is dependent upon—(1) the rate of the heart’s beat; 
(2) the quantity of blood forced into the arteries at euch 
beat; (3) the calibre of the smaller yessele. All of these, 
and consequently the capillary circulation which depends 
upon arterial pressure, are under the control of the nervous 
system (see Chap. XVIL). 

The Pulse. When the left ventricle contracts it forces 

. a certain amount of blood into the aorta, which is already 
distended and on account of the resistance in front cannot 
empty itself so fast as the contracting ventricle fills it. As 
a consequence its elastic walls yield still more-—it enlarges 
both transversely and longitudinally and if exposed in a 
living animal can be seen and felt to pulsate, swelling out 
at each systole of the heart, and shrinking and getting rid 
of the excess during the pause, A similar phenomenon 
can be observed in all the other large arteries, for just as 
the contracting ventricle fills the aorta faster than it emp- 
ties (the whole period of tho diastole of the heart being 
required for emptying the aorta of the blood sent in 
during the systole) so the increased tension in the aorta 
immediately after the cardiac contraction, drives on some 
of its contents into its branches, and fills these faster than 
they are emptying and so causes a dilatation of them also, 
which only gradually disappears as the aortic tension falls 
before the next systole. Hence after each beat of the heart 
there is a sensible dilatation of all the larger arteries, known. 
as the pulse, which becomes less and less marked at points 
on the emaller branches farther from the heart, but which in 
health can readily be recognized on any artery large enough 
to be felt by the finger through the skin, ete. The radial 
urtery near the wrist, for example, will always be felt tense 
by the finger, since it is kept overfilled by the heart in the 
way already deseribed. But after each heart-beat it be- 
comes more rigid anid dilates a little, the increased disten- 
sion and rigidity gradually disappearing as the artery 
passes on the excess of blood before the next heart-beat. 


THE PULSE. 


‘The pulse is then a wave of increased pressure started by 
the ventricular systole, radiating from the semilunar valves 
over the arterial system, and gradually disappearing in 
the smaller branches. In the aorta the pulse is most marked, 
for the resistance there to the transmission onwards of the 
blood sent in by the heart is greatest, and the elastic tube 
m which it consequently accumulates is shortest, and so the 
increase of pressure and the dilatation caused are consider- 
able, The aorta, however, gradually squeezes out the ex- 
cess blood into its branches and so this becomes distributed 
over a wider area, and these branches having less resistance 
m front find less and less difficulty in passing it on; conse- 
quently the pulse-wave becomes less and Jess conspicuous 
and finally altogether disappears before the capillaries are 
reached, the excess of liquid in the whole arterial system 
after a ventricular systole being too small to sensibly raise 
ihe mean pressure once it has been widely distributed 
over the elastic vessels, which is the case by the time the 
wayo has reached the small branches which supply the ca- 
pillaries, 

The pulse-wave travels over the arterial system at the 
rate of about 9 meters (29.5 feet) in a second, commencing 
at the wrist 0.159 seconds, and in the posterior tibial artery 
at the ankle 0.193 seconds, after the ventricular systole. 
The blood itself does not of course travel as fast as the 
pulse-wave, for that quantity sent into the sortw at each 
heart-beat does not immediately rush on over the whole 
arterial system, but by raising the local pressure causes the 
vessel to squeeze out faster than before some of the blood it 
already contains, and this entering its branches raises the 
pressure in them and causes them to more quickly fill their 
branches and raise the pressure in them; the pulse-wave or 
wave of increased pressure is transmitted in this way much 
faster than any given portion of the blood. How the 
wave of increased pressure and the liquid travel at differ- 
ent rates may be made clearer perhaps by picturing what 
would happen if liquid were pumped into one end of an 
already full elastic tube, closed at the other end. “At the 
closed end of the tube a dilatation and increased tension 





242 THE HUMAN BoDY. 


would be felt immediately after each stroke of the pump, 
although the liquid pumped in at the other end would have 
remained about its point of entry; it would cause the pul- 
sation not by flowing along the tube itself, but by giving a 
push to the liquid already in it. If instead of absolutely 
closing the distal end of the tube one brought about a 
state of things more nearly resembling that found in the 
arteries by allowing it to empty itself against a resistance, 
say through a narrow opening, the phenomena observed 
would not be essentially altered; the increase of pressure 
would travel along the distended tube far faster than the 
liquid in it. 

‘The pulse being dependent on the heart’s systole, ‘* feel- 
ing the pulse” of course primarily gives a convenient means 
of counting the rate of beat of that organ. To the skilled 
touch however it may tell a great deal more, as for example 
whether it is a readily compressible or ‘soft pulse” show- 
ing a low arterial pressure, or tense and rigid (“a hard 
pulse”) indicative of high arterial pressure, and soon, In 
adults the normal pulse rate may vary from sixty-five to 
seventy-five. In the same individual it is faster when 
standing than when sitting, and when sitting than when 
lying down. Any exercise increases its rate temporarily 
and so does excitement; a sick person’s pulse should not 
therefore be felt when he is nervous or excited (as the 
physician knows when he tries first to get his patient calm 
and confident), as it is then difficult to draw correct 
conclusions from it. In children the pulse is quicker than 
in adults, and in old age slower than in middle life, + 

The Rate of the Blood-Flow. As the yaseular system 
becomes more capacious from the aorta to the capillaries 
the rate of flow in it becomes proportionately slower, and 
as the total area of the channels diminishes again from the 
capillaries to the ven cave, 80 does the rate of flow quicken 
again, just as a river current slackens where it spreads out, 
and flows faster where it is confined ne a narrow er ec oRAnnel 


make the water flow in a narrower channel and ¢0 with a 





SECONDARY AIDS TO THE CIRCULATION. 43. 


more rapid current, Actual measurements as to the rate 
of flow in the arteries cannot be made on man, but from 
experiments on lower animals it is calculated that in the 
human carotid the blood flows about 400 millimeters ( 16 
inches) in a second, In the capillaries the current travels 
only from 0.5 to 0.74 mm. (¢5 to gy Inch) in a second. 
The total time taken by a portion of blood in getting from 
the aorta through the carotid and its branches, and the 
capillaries, and then throngh veins to the right auricle, 
that is in going round the systemic circulation, is about 
23 seconds—of which time about one second is spent in 
the capillaries; each portion of blood on its course from 
the lust artery to the first vein passes through a length 
of capillary which on the average is 0.5 mm. (7, inch). 
The rate of flow im the great veins is about 100 mm, (4 
inches) in a second, but is subject to considerable yaria~ 
tions dependent on the respiratory and other movements 
of the Body (see below). 

Causes of the Circulation. While the heart’s 
beat is the great driving force of the circulation, certain 
other things help more or less—viz. gravity, compression of 
the veins, and aspiration of the thorax, All of thom are, 
however, quite subsidiary; experiment on the dead Body 
shows that the injection of whipped blood into the aorta 
under a less force than that exerted by the left ventricle 
during life, is more than sufficient to drive it round and 
back by the ven cave. Not unfrequently the statement 
is made in books that, probably, the systemic capillaries 
have an attractive force for arterial blood and the pulmonary 
capillaries for yenous blood, but there is not the slightest 
evidence of the correctness of such a supposition, nor any 
necessity for making it. 

The Influence of Gravity. Under ordinary cireum- 
stances this may be neglected, eince in parts of the Body 
below the level of the heart it will assist the flow in the 
arteries and impede it equally in the veins, while the reverse 
isthe case in the upper parts of the Body. In certuin cases, 
however, it is well to bear these points in mind. A part 
* congested” or gorged with blood should if possible be 





24 THE HUMAN BODY. 


raised go as to make the back-flow in its veins easier; and 
sometimes when the heart is acting feebly it may be able 
to drive blood along arteries in which gravity helps, but not 
otherwise. Accordingly in a tendency to fainting it is best 
to lie down, and make it easier for the heart to send blood 
up to the brain, bloodlessness of which is the cause of the 
loss of consciousness in a fainting-fit. In fact so long as 
the bfeathing continues the aspiration of the thorax will 
keep up the venous flow (see below), while, in the cireum- 
stances supposed, a slight diminution in the resistance op- 
posed to the arterial flow may be of importance. The head 
of a person who has fainted should accordingly never be 
raised until he has undoubtedly recovered, a fact rarely 
borne in mind by spectators who commonly rush at once to 
lift any one whom they see fall in the street or elsewhere. 

The Influence of Transient Compression of the Veins. 
The valves of the veins being so disposed as to permit only 
a flow towards the heart, when external pressure empties a 
vein it assists the circulation. Continuons pressure, as by 
a tight garter, is of course bad since it checks all subse- 
quent flow through the vessel, but intermittent prossure, 
such as exerted on many veins by muscles in the ordi- 
nary movements of the Body, acts as a pump to force on 
the blood in them. 

The valves of the veins have another use in diminishing 
the pressure on the lower part of those vessels in many 
regions. If, for instance, there were no valves in the long 
saphenous vein (p. 214) of the leg the weight of the whole 
column of blood in it, which in the erect position would be 
about a meter (39 inches) high, would press on the lower 
part of the vessel. But each set of valves in it carries the 
weight of the column of blood between it and the next set 
of valves above, and relieves parts below, and so the weight 
of the column of blood is distributed and does not all bear 
on any one point. 

Aspiration of the Thorax, Whenever » breath is drawn 
the pressure of the air on the vessels inside the chest is di- 
minished, while that on the other vessels of the Body is un- 
affected. In consequence blood tends to flow into the chest. 





PROOFS OF THE CIRCULATION. 245 


Tt cannot, however, flow back from the arteries on account 
of the semilunar valves of the aorta, but it readily is pressed, 
or in common language “sucked,” thus into the great 
veins close to the heart and into the right auricle of the 
latter. The details of this action must be omitted until 
the respiratory mechanism has been considered. All parts 
of the pulmonary cirenit being within the thorax, the 
respiratory movements do not influence it, except in so far 
as the distension or collapse of the lungs influences the 
calibre of their vessels. 

The considerable influence of the respiratory movements 
upon the venous circulation can be readily observed. In 
thin persons the jugular vein in the neck ean often be 
seen to empty rapidly and collapse during inspiration, and 
fill up faster than it empties during expiration, thus exhib- 
iting a sort of venous pulse. Every one, too, knows that 
by making a violent and prolonged expiration, as exhibited 
for example by a child with whooping-cough, the flow 
in all the veins of the head and neck may be checked, 
causing them to swell up and hinder the capillary cireuli- 
tion until the person becomes ** black in the face,” from the 
engorgement of the small vessels with the dark-colored ve- 
nous blood. 

In diseases of the tricuspid valve another form of venous 
pulse is often seon in the superficial veins of the neck, since 
at each contraction of the right ventricle some blood is 
driven back through the right auricle into the veins. 

Proofs of the Circulation of the Blood, The older 
physiologists believed that the movement of the blood was 
an ebb and flow, to and from each side of the heart, and out 
and in by both arteries and veins. They had no idea of 
circulation, but thought pure blood was formed in the lungs 
and impure in the liver, and that these partially mixed in 
the heart through minute pores supposed to exist in the 
septum. Servetus, who was burnt alive by Calvin in 1553, 
first showed that there was a continuous passage through 
the lungs from the pulmonary artery to the pulmonary 
veins, but the great Englishman Harvey first, in loctures 
delivered in the College of Physicians of London about 








246 THE HUMAN BODY. 


1616, demonstrated that the movement of the blood was a 
continuous circulation as we now know it, and so laid the 
foundation of modern Physiology. In his time, however, 
the capillary vessels had not been discovered, so that al- 
though he was quite certain that the blood got somehow 
from the final branches of the aorta to the radicles of the 
yenous system, he did not exactly know how. 

‘The proofs of the course of the circulation are at present 
quite conclusive and may be summed up as follows. (1) 
Blood injected into an artery in the dead Body will return 
by a vein; but injected into a vein will not pass back by an 
artery. (2) The anatomical arrangement of the valves of 
the heart and of the veins shows that the blood can only 
flow from the heart, through the arteries and back fo the 
heart by the veins. (3) A cut artery spurts from the end 
next the heart, a cat vein bleeds most. from the end 
farthest from the heart. (4) A portion of a vein when 
emptied fills only from the end farthest from the heart. 
‘This experiment can be made on the veins on the back 
of the hand of any thin person, especially if the vessels 
be first gorged by holding the hand in a dependent posi- 
tion for a few seconds. Select then a vein which runs 
for an inch or so without branching, place one finger on 
its distal end and then empty it up to its next branch 
(where valves usually exist) by compressing 1t from below 
up. The vessel will then be found to remain empty as 
long as the finger is kept on its lower end, but will fill 
immediately when it is removed; which proves that the 
valves prevent any filling of the vein from its heart end 
backwards. (5) If & bandage be placed around the arm, 
0 a8 to close the superficial veins but not tight enough to 
occlude the deeper-seated arteries, the veins on the distal 
side of the bandage will become gorged and those on its 
proximal side empty, showing again that the veins only 
receive blood from their ends turned towards the capilla- 
ries. (6) In the lower animals direct observation with the 
microscope shows the steady flow of blood from the arte- 
ries through the capillaries to the veins, but never in the 
opposite direction, 


CHAPTER XVII. 


THE REGULATION OF THE HEART AND BLOOD- 
VESSELS BY THE NERVOUS SYSTEM. 


The Need of Co-ordination. For the safe and harmo- 
nious working of the cireulatory appuratus it is obviously 
necessary that there be some mode of mutual interaction 
between the heart and the blood-vessels: if the heart beat 
and the arteries relaxed or contracted, each without any 
reference to the other, no orderly capillary flow could be 
maintained. To secure that, the work done by the heart and 
the resistance to the blood-flow offered in the vessels must 
at any given moment be correlated; so that.the heart shall 
not by too powerful action over-distend or perhaps burst 
the small arteries, nor the latter contract too much and so, 
by increasing the peripheral resistance, raise the aortic pres- 
sure to a great height and increase unduly the work to be 
done by the left ventricle in forcing open the semilunar 
valves. Aguin, the total amount of blood in the Body ix 
not sufficient to keep all its organs supplied with the 
amount needful for the full exercise of their activity at 
one time, and in the Body accordingly we never find all 
its parts hard at work at the same moment. If when one 
group of muscles was set at work and needed an oxtra 
blood-supply, this was attained merely by inereasing the 
heart’s activity and keeping up a faster blood-flow every- 
where through the Body, there wonld be a clear waste of 
force, much as if the chandeliers in a house were 80 ar- 
ranged that when a larger flame was wanted at one burner 
it could only be obtained by turning more gas on at all the 
rest at the same time; besides the big tap at the gas-meter 
regulating the general supply of the house, local taps at 





248 THE HUMAN BODY, 


each burner are required which regulate the gas-supply to 
each flame independently of the rest. A similar arrange- 
ment isfound in the Body. Certain nerves control the 
calibre of the arteries supplying different organs and, when 
the latter are set at work, allow their arteries to dilate and 
so increase the amount of blood flowing through them 
while the general circulation elsewhere remains practically 
unaffected. The resting parts at any moment thus get 
just enough blood to maintain their healthy nutrition and 
the working parts get more; and as certain organs come to 
rest and others are set in activity, the arteries of the one 
narrow and of the other dilate; in this way the distri- 
bution of the blood in the Body is undergoing constant 
changes, parts which at one time contain much blood at 
another haying but little. In addition, then, to nervous 
organs regulating the work of the heart and the arteries 
with reference to one another, we have to consider another 
set of vascular nerves which govern the local blood-supply 
of different regions of the Body. 

‘The Nervos of the Hoart, ‘The heart gets nerves from 
three sources, (1) From nerve-cells buried in its own sub- 
stance and known as its intrinsic ganglia, (2) From the 
tenth pair (pneumogastrics) of cranial nerves. (3) From 
the sympathetic nervous system. Tho intrinsic ganglia 
keep the heart beating, and the other two sets of nerves 
control the rate and force of the beat. 

Tho Intrinsic Heart-Nerves. The ganglia of the heart 
lie for the most part in the partition between the auricles 
andalong the line of junction of the auricles and yentricles ; 
a fow are found also in the upper parts of the latter. From 
some of them arise nerve-fibres which go to the muscles of 
the heart, while others are connected with the endings of 
the extrinsic nerves reaching the organ ; and probably all 
communicate by a network of nerve-fibres. 

The heart is an automatic organ: its beat, like the 
moyement of filaments of a ciliated cell, depends on its 
own structure and properties and not on anything outside 
itself. This is proved by the fact that ihe heart out out of 
an animal which has just becn decapitated, and entirely re- 








CAUSE OF THE HEART'S BEAT. 249 


moved from all the reat of the body, will go on beating for 
some time ; a time which is very short in the case of warm- 
blooded animals, the tissues of which die very soon when 
the blood-flow through them ceases, but which may extend 
to hours or even days in the excised heart of frog or 
turtle, if itbe kept from drying up. Still, whether the time 
of its continuance be shorter or longer, the fact that the 
heart-beat continues after complete excision of the organ 
proves that it is not dependent on stimuli reaching it from 
other parts of the Body, In the ciliated cell we had no 
differentiation into muscle and nerve—its contractile and 
automatic parts if separated at all were not optically distin- 
guishable and we could only speak of the cell as still retain- 
ing both of those primitive protoplasmic properties. But 
in the heart, where we find distinct muscles and nerves, the 
question naturally arises in which of them does the anto- 
matic power reside. We have already seen (Chap. X.) that 
muscles-elsewhere possess no automaticity : they only con- 
tract under the inflnence of a recognizable stimulus, and 
though the muscular fibres of the heart do differ somewhat 
from other muscular fibres in the Body, it is still a priori im- 
probable that they are automatic and we are accordingly led 
rather to suppose that the stimulus resides in the ganglion- 
cells of the heart, especially since we know that nerve-cells 
elsewhere are automatic. Experiment confirms this suppo- 
sition. Ifa frog's heart, removed from the body and still 
beating, be cut into several pieces with a sharp razor if will 
be found that, while bits of the auricles and the baee of the 
ventricle go on beating, the apical portions of the ventricle 
lie at rest—not because the muscle there is dead and has 
lost: its contractility, for these bits if excited by any ex- 
traneous muscular stimulus will still beat, but because 
that part of the heart possesses no automaticity. Now this 
is just the purt of the frog’s heart that has no ganglion-cells 
of its own, while the parts that go on beating are those 
which possess them ; hence we conclude that the stimulus 
originates in the nerye-cells of tho organ and is from them 
carried by its nerve-fibres to the muscles. Tho excitant of 
the nerve-cells being still unknown we call them automatic 








250 THE HUMAN BODY. 


in the restricted physiological sense of the word. ‘The 
primary cause of the heart's beat lying thus in itself, we have 
next to see how this beat is controlled from outside and ¢o- 
ordinated with the condition of the rest of the Body at any 
given moment. 

Nervos Slowing the Heart’s Beat. Each pneumogas- 
tric trunk sends several branches to the heart. Certain of 
these contain fibres which when excited slow, or even alto- 
gether stop, the beat of the heart and are hence known as 
the cardio-inhibitory fibres. 

If one pneumogastric trunk be divided as it runs down 
the neck and its peripheral, or lower, end be stimulated 
feebly the heart's beat becomes less frequent, while a more 
powerful stimulation will completely stop it for a few 
seconds, as if its muscles were suddenly paralyzed. If the 
experiment be performed upon a narcotized animal, the heart 
of which is at the same time exposed by opening the chest, 
it will beseen that during the stoppage the heart lies flabby 
and relaxed in diastole; the excitation of the nerve does 
‘uot stop the heart’s beat, as might perhaps be supposed, by 
keeping it in a state of permanent tetanic contraction, but 
it annals its contractions and throws it into a state of rest ; 
the nerve-fibres concerned are not excitant but inhibitory, 
stopping instead of calling forth the activity of the part on 
which they act. Whether their influence is exerted di- 
rectly on the muscular fibres of the heart or upon it) in- 
trinsic ganglia, abolishing their automatic activity and so 
eutting off the stimuli which normally radiate from them 
to the muscles, is not certainly known, but the latter view 
is probably the correct one. In any case the full inhibi- 
tory power usually lasts only a short time; even if the 
pnenmogustric stimulation be continued the heart will al- 
most always after a few seconds recover from its influence 
and commence to beat again, 

‘These cardio-inhibitory fibres originate in a collection of 
nerve-cells-in the medulla oblongata known as the cardio- 
inhibitory centre. This centre is automatic and always in 
a state of slight excitation, feebly stimulating the fibres 
proceeding from it and slightly slowing the heart’s beat. 


_ 





CARDIAU LNHIBITION. 


‘This is chown by the fact that if both pneumogastric nerves 
be cut in the neck the heart at once begins to beat a little 
faster than before; the brake, so to speak, has been taken 
off it. 

The Influence upon Arterial Pressure of Inhibiting 
tho Hoart. If the heart be entirely stopped arterial pres- 
snre will of course fall very rapidly, since the distended 
arterial system will go on emptying itself through the capil- 
laries into the veins, without receiving any fresh supply at 
its cardiac end. So tooif the heart be made to beat slower, 
but with the same force in each stroke, it follows from the 
facts pointed out in the last chapter (p. 238) that arterial 
pressure will fall to a new and lower level, at which the 
elastic arteries are only stretched enough to squeeze out in 
minute as much ag they receive, As a matter of fact, 
when the heart is made to beat slower by weak pnenmo- 
gastric stimulation each beat isusnally a little more power- 
ful than before. However, this extra force is not sufficient 
to compensate entirely for the slower rate and so the gen- 
eral arterial pressure falls. 

Use of tho Cardio-Inhibitory Mechanism. Although 
the canlio-inhibitory centre is automatic and always ina 
state of slight activity it is also greatly under the control of 
afferent nerve-fibres reaching it and which can arouse it toa 
much greater degree, and so reflexly control the heart's beat. 
If a frog be rendered insensible and its abdominal cavity 
opened, it will be found that one or two smart taps on the 
intestine will cause the heart to stop in diastole. If, how- 
ever, the pneumogastric nerves, or the spinal cord, or the 
anterior roots of the spinal nerves, or the communicating 
branches between the sympathetic nerves of the abdomen 
aud the spinal nerves, be cut previously, then striking the in- 
testine has no influence upon the heart; nor has it if the 
eardio-iuhibitory centre in the medulla oblongata be pre- 
viously destroyed. We thus get evidence that the mechani- 
cal stimulation of the intestinal nerves stops the heart re- 
fiexly through the pneumogastrics, the afferent impulses 
traveling from the sympathetic into the spinal nerves and 
passing then up the spinal cord to the cardio-inhibitory 








252 THE HUMAN BODY. 


centre, where they are reflected us efferent impulses down 
the pnenmogastric trunks to the heart. In man and other 
mammals similar arrangements exist, the afferent fibres pass- 
ing from the alimentary canal through the solar plexus (p.172) 
which lies behind the stomach. It is by exciting them and 
so reflexly stopping the heart, that men are sometimes killed 
by a severe blow on the abdomen or even occasionally by a 
large draught of very cold water, the sudden cold acting as 
a thermal stimulus, through the walls of the stomach, on the 
nerve-fibres outside. A hot and very thirsty person requir- 
ing « big drink should therefore not take too cold water— 
or if he does, swallow it only a mouthful at a time. 

The blood-vessels of the alimentary canal are very numer= 
ons and capacions and form one of the largest vascular tracts 
of the whole Body, and through the reflex mechanism above 
described we see how they may control the heart's beat, 
Probably if the heart is beating too frequently and keeping 
up too high a pressure in them, the sympathetic nerve- 
fibres in their coats are stimulated and then, reflexly, 
through the cardio-inhibitory centre slow the heart’s beat 
and lower the general arterial pressure ; and so we get one 
co-ordinating mechanism by which the heart and blood-vea- 
sels are made to work in unison. 

Some other afferent nerves are also known to be in con- 
nection with the cardio-inhibitory centre. For instance, 
some persons are made to faint bya strong emell, the olfac- 
tory nerves exciting the cardio-inhibitory centre and stop- 
ping or greatly slowing the heart. Deaths from the admin- 
istration of chloroform are also usually brought aboutin the 
same way, the vapor stimulating the sensory nerves of the 
air-passages which then excite powerfully the cardio-inhibi- 
tory centre and stop the heart. 

‘The Accelerator Nerves of the Heart. These originate 
in the spinal cord, from which they pass by communicating 
branches to the lowest cervical and upper dorsal sym- 
pathetic ganglia and thence to the heart. When stimu- 
lated they cause the heart to beat quicker, but under what 
conditions they are employed in the physiological working 
of the Body is not known. 











NERVES OF THE BLOOD. VESSELS. 253 





Tho Nerves ofthe Blood-Vessels, ‘The arteries,as already 
pointed out, possess a muscular coat composed of fibres 
arranged across them, so that their contraction will narrow 
the vessels. This coat is most prominent in the smaller 
vessels, those of the size which go to supply separate organs, 
but disappear again in the amallest branches which are about 
to divide into capillaries for the individual tissue elements 
ofan organ. These yuscular muscles are under the control 
of certain nerves called vaso-motor (p. 186) and these latter 
can thus govern the amount of blood reaching any organ at 
agiven time. The vaso-motor nerves of the arteries are, 
like those of the heart, intrinsic and extrinsic. The intrin- 
sic fibres originate from ganglion-cells in the coats of the 
arteries or lying alongside them, while the extrinsic origi- 
nate from cells in the cerebro-spinal centre, from which 
they commonly pass into the sympathetic system before 
they reach the vessels. The intrinsic ganglia, like those of 
the heart, are automatic and tend to keep the muscular 
coats of the arteries in a constant state of feeble contrac- 
tion so that, apart from their physical elasticity, the arteries 
always hold a certain grip on the blood. The contraction, 
however, is as a rule persistent and steady, or tonic, instead 
of rhythmic like that of the heart, although slow rhythmic 
contractions haye been seen to occur in some arteries, The 
difference probably depends rather on the kind of muscle 
concerned in each case than on the gunglion-colls, since 
plain muscular tissue, such as is found in the arteries, con- 
tracts so slowly and remains contracted so long when excited, 
that stimuli reaching it at intervals which would give a 
rhythmic beat in cardiac muscle, would keep the arterial per- 
manently contracted or tetanized. As in the heart, the 
activity of the arterial intrinsic nervous mechanism is 
under the control of extrinsic nerves, certain of which, the 
vaso-constrictors, answer to the accelerator nerves of the 
heart and increase the activity of the intrinsic ganglia, 
while others, corresponding to the cardio-inhibitory fibres, 
check the activity of the intrinsic vascular nerves, 

‘The Vaso-Motor Centre. The yaso-constrictor extrinsic 
arterial nerves are nearly always in a state of slight activity, 








264 THE HUMAN BODY, 


keeping the arteries more constricted than they would be 
under the influence of their intrinsic nervesalone. Accord- 
ingly if they are cut, or paralyzed, in any region of the Body 
its arteries dilate and it becomes flushed with blood. Those 
of the external ear, for example, run in the cervical sympa- 
thetic, from the lower part of the neck where they leave the 
spinal cord, until they reach the arterial branches for the 
ear and ran along the smaller twigs to it. If, therefore, 
the cervical sympathetic be divided on one side in an 
anwsthetized rabbit, the ear on that side becomes red and 
warm from the dilatation of its arteries and the extra 
amount of blood flowing through it. If, however, that end 
of the eut nerve still attached to the ear be excited electri- 
cally or otherwise, the ear arteries contract gradually until 
their passage is almost closed up, and the whole organ be- 
comes cold and very pale. Although these vaso-constrictor 
fibres are thus shown to pass through the cervical sympa- 
thetic, other experiments show that they really originate 
in a group of nerve-cells in the medulla oblongata, and 
from there run down the spinal cord to the lower part of 
the neck, where they pass out in the anterior roots of some 
spinal nerves and reach the sympathetic system. The same 
is true of nearly all extrinsic yaso-constrictor nerve-fibrea 
in the Body. Some few possibly-arise from centres in the 
spinal cord, but the great majority come primarily from 
the medulla oblongata, and the collection of nerve-cells 
there from which they spring is known as the vaso-motor 
centre; a better name would be the vaso-constrictor centre. 

Tho Control of tho Vaso-Motor Centre. The yaso- 
motor centre is automatic; that is to say it maintains o 
certain amount of activity of its own, independently of any 
stimuli reaching it through afferent norve-fibres. Never- 
theless, like nearly all automatic nerve-centres, it is under 
reflex control, so that its activity may be increased or les~ 
sened by afferent impulses conveyed to it. Nearly every sen- 
sory nerve of the Body is in connection with it; any stimu- 
lus giving rise to pain, for example, excites it, and so 
constricting the arteries, increases the peripheral resist- 
ance to the blood-flow and raises arterial pressure. On 





VASO-DILATOR NERVES. 255 


the other hand, certain fibres conveying impulses from tho 
heart inhibit the centre and dilate the arteries, lower 
blood-pressure, and diminish the resistance to be overcome 
by the heart. These fibres ran in branches of the pneumo- 
gastric, and are known as the depressor fibres, or in certain 
animals, for example the rabbit, where they are all collected 
into one branch, as the depressor nerve. If this nerve be 
divided and its cardiac end stimulated no effect is pro- 
duced, but if its central end (that still connected 
with the rest of the pneumogastric trunk and through it 
with the medulla oblongata) be stimulated, arterial pressure 
gradually falls; this result being dependent upon a dilata- 
tion of the small arteries, and consequent diminution of 
the peripheral resistance, following an inhibition of the 
yaso-motor centre brought about by the depressor nerve, 
‘Through the depressor nerve the heart can therefore influ- 
ence the calibre of the small arteries and, by lowering 
aortic pressure, diminish its own work if need be. 
Blushing. The depressor nerves control a great part of 
the vaso-motor centre, and so can bring about dilatation 
of a large number of arteries—their influence is called into 
play when general arterial pressure is to be lowered, but is 
useless for controlling local blood-supply. This is man- 
aged by other afferent nerves, each of which inhibits a 
small part only of the vaso-motor centre, governing the 
arteries of a limited tract of the Body; the dilatation of 
these increases the amount of blood flowing through the 
particular region to which they are distributed, but does 
not affect the total resistance to the blood-flow sufficiently 
to influence noticeably the general pressure in the arterial 
system. In blushing, for example, under the influence of 
an emotion, that part of the vaso-motor centre which sup- 
plies constrictor nerves to the arteries of the skin of the 
neck and face, is inhibited by nerve-fibres proceeding from 
the cerebrum to the medulla oblongata, and the face and 
neck consequently become full of blood and flush up. 
Quite similar phenomena occur under other conditions in 
many parts of the Body, although when not visible on the 
surface we do not usually call them blushes. The mucous 



































THE HUMAN BODY. 


membrane lining the empty stomach is pallid and its ar- 
teries contracted, but as soon as food enters the 
it becomes red and full of blood; the food stimulating 
afferent nerve-fibres there, which inhibit that part of the 
yaso-motor centre which governs the gastric arteries. 

Taking Cold. This common disease is not unfrequent- 
ly caused through undue reflex excitement of the vaso~ 
motor centre. Cold acting upon the skin stimulates, through 
the afferent nerves, the region of the vaso-motor centre goy- 
erning the skin arteries, and the latter become contracted, 
as shown by the pallor of the surface. This has a two-fold 
influence—in the first place, more blood is thrown into in- 
ternal parts, and in the second, contraction of the arte- 
ries over so much of the Body considerably raises the gen- 
eral blood-pressure. Consequently the vessels of internal 
parts become overgorged or “‘ congested,” a condition which 
readily passes into inflammation. Accordingly prolonged 
exposure to cold or wet is apt to be followed by catarrh or 
inflammation of more or less of the respiratory tract caus- 
ing bronchitis, or of the intestines causing diarrhma, In 
fact the common summer diarrhea is far more often due 
to a chill of the surface, causing intestinal catarrh, than to 
the fruits eaten in that season which are so often blamed 
for it. The best preventive is to wear, when exposed to 
great changes of temperature, a woolen or at least a cotton 
garment over the trank of the Body; linen is so good a 
conductor of heat that it permits any change in the exter- 
nal temperature to act almost at once upon the surface of 
the Body. After an unavoidable exposure to cold or wet 
the thing to be done is of course to maintainthe cutaneous 
circulation; for this purpose movement should be persisted 
in, or a thick dry outer covering put on, until warm and 
dry clothing can be obtained. 

For healthy persons « temporary exposure to cold, a8 a 
plunge in a bath, is good, since in them the sudden contrae- 
tion of the cutaneous arteries soon passes off and is sue- 
ceeded by a dilatation causing a warm healthy glow on the 
surface. If the bather remain too long in cold water, how- 
ever, this reaction pusses off and is succeeded by u more 








VASO-DILATOR NERVES. 257 


persistent chilliness of the surface, which may even last 
ull day. The bath should therefore be left before this 
oceurs, but no absolute time can be stated, as the reaction 
is more marked and lasts longer in strong persons, and in 
those used to cold bathing, than in others. 

‘Vaso-Dilator Nerves. We have already seen, in the case 
of the stomach, one method by which a locally increased 
blood-supply may be brought about in an organ while it is 
at work, Usually, however, in the Body this is managed 
in another way; by vaso-dilator nerves which inhibit or 
paralyze, not the yaso-motor centre, but the intrinsic nery- 
ous supply of the blood-vessels, The nerves of the skeletal 
muscles for example contain two sets of fibres: one motor 
proper and the other vaso-dilator. When the muscle con- 
tracts in a reflex action or under the influence of the will both 
sets of fibres are excited; so that when the organ is set at 
work its arteries are simultancously dilated and more blood 
flows through it, Quite a similar thing occurs in the sali- 
vary glands. Their cells, which form the saliva, are aroused 
to activity by special nerve-fibres; but the gland nerve also 
contains vaso-dilator fibres which simultaneously cause a 
dilatation of the gland artery, Through such arrange- 
ments the distribution of the blood in the Body at any 
moment is governed: so that working parts shall have 
abundance and other parts less, while at the same time the 
general arterial pressure remains the same on the average; 
since the expansion of a few small local branches but little 
influences the total peripheral resistance in the vascnlar sys- 
tem. Moreover, commonly when one set of organs is at 
work with its vessels dilated, others are at rest with their 
arteries comparatively contracted, and so a general average 
blood-pressure is maintained. Few persons, for example, 
feel inclined to do brain work after a heavy meal: for then 
a great part of the blood of the whole Body is led off into 
the dilated vessels of the digestive organs, and the brain 
gets asmaller supply. On the other hand, when the brain 
is at work its vessels are dilated and often the whole head 
fluehed: and so excitement or hard thought after a meal 
49 ‘ery apt to produce an attack of indigestion, by diverting 











258 THE HUMAN BODY. 


the blood from the abdominal organs where it ought to be 
at that time. Young persons, whose organs have a super- 
abundance of energy enabling them to work under unfayor- 
able conditions, are less apt to suffer in such ways than 
their elders. One sees boys running actively about after 
eating, when older people feel a desire to sit quiet and ru- 
minate—or even go to sleep. 





CHAPTER XVIII. 
THE SECRETORY TISSUES AND ORGANS. 


Definition. In a strict sense of the terms every pro- 
cess in which substances are separated from the blood, 
whether they be altered or unaltered, is “secretory” and 
every product of such a separation is a‘ secretion;” in this 
sense secretions would be separable into three classes, (1) 
Liquids or gases transuding on free surfaces of the Body, 
whether external or internal; (2) the liquids (lymph) 
moistening the various tissues of the Body directly, filling 
the interstices between them and not contained in definitely 
limited cavities ; (3) all the solid tissues of the Body since, 
after an early period of embryonic life, they are built up 
from materials derived from the blood. Secretions would 
thus come to include all constituents of the Body except 
the blood itself but, while it is well to bear in mind that 
the whole Body is in such a way derived from the blood, in 
practice the term secretion is given a narrower connota- 
tion, the solid tissues and the lymph being excluded; so that 
a secretion is a material (liquid or gaseous) derived from the 
blood and poured out on a free surface, whether that of the 
general exterior or that of an internal cavity. Such true 
secretions fall into two classes; one in which the product 
is of no further use in the Body and is merely separated 
for removal, as the urine; and one in which the product is 
intended to be used, for instance as a solvent in the diges- 
tion of food. The former group are sometimes distin- 
guished as excretions and the latter as secretions proper, but 
there is no real difference between them, the organs and pro- 
cesses concorned being fundamentally alike in each case. A 
better division is into ¢ransudata and secretions, a transuda- 











260 THE HUMAN BODY. 


tion being a product which contains nothing which did 
not previously exist in the blood, and then in such quantity 
as might be derivable from it by merely physical processes; 
while a secretion in addition to transudation elements con- 
tains a specific element, due to the special physiological 
activity of the secretory organ; being either something 
which does not exist in the blood at all or something which. 
existing in the blood in small quantity, exists in the seere- 
tion in such a high proportion that it must have been 
actively picked up and conveyed there by the seeretory 
tissues concerned. For instance, the gastric juice contains 
free hydrochloric acid which does not exist in the blood; 
and the urine contains so much urea that we must suppose 
its cells to have a peculiar power of removing that body 
from the liquids flowing near them. ‘This subdivision is 
also justifiable on histological grounds ; wherever there is 
a secreting surface it is covered with cells, but these where 
transudata are formed (as on the serous membranes) are 
mere flat scales, with little or no protoplasm remaining in 
them, while the cells which line a true secreting organ are 
cuboidal, spherical, or columnar, and still retain, with 
their high physiological activity, a good deal of their primi- 
tive protoplasm i in a but slightly modified state, 

Organs of Socrotion, The simplest form in which a 
secreting organ occurs (A, Fig. 88) is that of a fat membrane 
provided with a layer of celle, a, on one side (that on which 
the secretion is poured out) and with a network of capil- 
lary blood-vessels, ¢, on the other. The dividing mem- 
brane, 0, is known as the basement membrane and is usually 
made up of flat, closely fitting connective-tissue corpuscles; 
supporting it on its deep side is a layer of connective tissue, 
d, in which the blood-vessels and lymphatics are supported. 
Such simple forme of secreting surfaces are found on the 
serous membranes but are not common; in most cases an 
extended area is required to form the necessary amount of 
secretion, and if this were attained simply by spreading ont 
plane surfaces, these from their number and extent would 
be hard to pack conveniently in the Body. Accordingly in 
most cases, the greater area is attained by folding the 





ft 
Tro, —Forms of glands A, simple secreting eurtage; te aaa 
6, basement membrane; ¢. capillaries 5,0. mocret: 
Cored vabula ‘ela Rect mm af ind, in allot 8 ths 
‘com ibular is: ompouun Facumone, glaint 
capillaries vot earnest 4 


icemose glands c, lke main d ‘luce, The etter a take bas been used 
Sein for tho basement membrane above, and for uranches of duet below 





|. 








262 THE HUMAN BODY. 


secreting surface in various ways so that a large surface can 
be packed in a small bulk, just as a Chinese lantern when 
shut up occupies much less space than when extended, 
although its actual surface remains of the same extent. Tn 
a few cases the folding takes the form of protrusions into 
the cavity of the secreting organ as indicated at C, Fig. 88, 
and found on some synovial membranes; but much more 
commonly the surface extension is attained in another way, 
the basement membrane, covered by its epithelium, being 
pitted in or involuted as at B. Such a secreting organ is 
known as a gland. 

Forms of Glands. In some cases the surface involu- 
tions are uniform in diameter, or nearly so, throughout (B, 
Fig. 88). Such glands are known as ¢udular; examples 
are found in the lining coat of the stomach (Fig. 97*); also 
in the skin (Fig.120+), where they form the sweat-glands. 
Tn other cases the involution swells out at its deeper end and 
becomes more or less sacculated (2); such glands are racemose 
or acinous. The small glands which form the oily matter 
poured out on the hairs (Fig.119t) are of this type. In both 
kinds the lining cells near the deeper end are commonly 
different in character from the rest; and around that part 
of the gland the blood-yessels form a closer network. 
These deeper cells form the true secreting elements of the 
gland, and the passage, lined with different cells, leading 
from them to the surface, and serving merely to carry off 
the secretion, is known as the gland duct. When the duct 
is undivided the gland is simple; but when, as is more 
usual, it is branched and each branch has a true secreting 
part at its end, we get a compound gland, tubular (@) or 
racemose (/, H)as the case may be. In such cases the 
main duct, into which the rest open, is often of considera- 
ble length, so that the secretion is poured out at some dis- 
tance from the main mass of the gland. 

A fully formed gland, H, thus comes to be a complex 
structure, consisting primarily of a duct, ¢, ductules, dd, 
and secreting recesses, e. The ducts and ductules are 
lined with epitheliam which is merely protective and differs 
in character from the secreting epithelium which lines the 


*P, 819. +P. 418. tP, 416, 








PROCESSES CONCERNED IN SECRETION. 268 





1 parts, Surrounding each subdivision and bind- 
ing it to its neighbors is the gland stroma formed of con- 
nective tissue, a layer of which also commonly envelops 
the whole gland, as its capsu/e. Commonly on looking at 
the surface of a large gland it is seen to be separated by 
partitions of its stroma, coarser than the rest,into /obes, 
of which answers toa main division of the primary duct; 
and the lobes are often similarly divided into smaller parts 
or lobules. In the connective tissue between the lobes and 
lobules blood-vessels penetrate, to end in fine capillary 
vessels around the terminal recesses. They never pene- 
trate the basement membrane, Lymphatics and nerves 
take a similar course; but there is reason to believe the 
nerve-fibres penetrate the basement membrane and be- 
come directly united with the secreting cells, 

The Physical Processes in Secretion. From ihe struc- 
ture of a gland it is clear that all matter, derived from the 
blood and poured into its cavity, must pass not only through 
the walls of the capillary blood-vessels, but also, by filtra- 
tion or dialysis, through the basement membrane and the 
lining epithelium. By filtration is meant the passage of a 
fluid under pressure through the coarser mechanical pores 
of a membrane, as in the ordinary filtering processes of a 
chemical laboratory; and the higher the pressure on the 
liquid to be filtered the greater the amount which, other 
things being equal, will puss through in a given time. 
Since in the living Body the liquid pressure in the blood 
capillaries is nearly always higher than that outside them, 
filtration is apt to take place everywhere toa greater or less 
extent, and will be increased in amount in any region by 
circumstances raising blood-pressure there, and diminished 
by those lowering it. ‘To a certain extent also the nature 
of the liquid filtered has an influence. True solutions, as 
those of salt in water, pass through unchanged; but solu- 
tions containing substances such as boiled starch or raw 
egg albumen, which swell up greatly in water rather than 
truly dissolve, are altered by filtration; the filtrate contain- 
mg less of the imperfectly dissolved body than the unfil- 
tered liquid. The higher the pressure the greater the pro- 








264 THE HUMAN BODY. 


portion of such substances which gets through; and if 
the pressure is slight the water or other solvent may alone 
pass, leaving all the rest behind on the filter. Under 
moderate preasure the blood may thus lose by filtration 
such bodies only as water and salines; while an increase of 
arterial pressure may lead to the passage of albumen and 
fibrinogen. Under healthy conditions, for example, the urine 
contains no albumen, but anything increasing the capillary 
pressure in the kidneys will cause it to appear. 

or osmosis has already been considered (p. 42); by it sub- 
stances pass through the intermolecular pores of a mem- 

brane independently of the pressure on either side, and for 
its occurrence two liquids of different chemical constitution 
are required, one on each side of the membrane. At least 
if diffusion takes place, as is probable, between two exactly 
similar solutions, the amount and character of the sub- 
stances passing opposite ways in a given time are exactly 
equal, so that no change is produced by the dinlysis; which 
pructically amounts to the same thing as if none occurred. 
When a solution is placed on one side of a membrane allow- 
ing of dialysis and pure water on the other, itis found that 
for every molecule of the dissolved body that passes one 
way a definite amount of water, called the endosmotic 
equivalent of that body, passes in the opposite direction. 
Orystalline bodies as a rule (hemoglobin is an exception) 
have a low endosmotic equivalent or are readily dialyzablo; 
while colloids such as gum and proteids, have a very high 
one, 60 that to get, by dialysis, a small amount of albumen 
through a membrane, a practically infinite amount of water 
must pass the other way, Accordingly, if we find such 
bodies in a secretion we cannot suppose that they haye been 
derived from the blood by osmosis, 

The Chemical Processes of Secretion. As above point- 
ed out certain secretions, called transudata, seem to be pro- 
ducts of filtration and dialysis alone, containing only such 
substances as those which are found in the blood plasma, 
more or less altered in relative quantity by the ease or diffi- 
culty with which they severally passed through the layers 
met with on their way to the surface. But in many cases 


ey a 


a 


THE SPECIFIC ELEMENTS OF SECRETIONS. 265 





the composition of a secretion cannot be accounted for in 
this way; it contains some specific element, either a substance 
which docs not exist in the blood at all and must therefore 
have been added by the secreting membrane, or some 
body which, although existing in the blood, does so in such 
minute proportion compared with that in which it is found 
in the secretion, that some special activity of the secreting 
cells is indicated; some affinity in them for these bodies by 
which eer actively pick them up. 

Each living cell, we have seen, is the seat of constant 
chemical activity, taking up materials from the medium 
about it, transforming and utilizing them, and sooner or 
later restoring their elements, differently combined, to the 
medium aguin. By such means it builds up and maintains 
its living snbstance, and obtains energy to carry on its daily 
work. While this is true of all cells in the Body, we find 
certain groups in which chemical metabolism is the promi- 
nent fact; cells which are specialized for this purpose just 
as muscular fibre is for contraction or a nerve-fibre for con- 
duction, and certain of these prominently metabolic tissues, 
exist in the true glands and produce or collect the specific 
elements of their secretions. Their chemical processes are 
no doubt primarily directed to their own nutritive mainte- 
nance; they live primarily for themselves, but their nutritive 
processes are such that the bodies formed in them and sent 
into the secretion are such as to be useful to the rest of the 
cells of the community; or the bodies which they specially 
collect, and in a certain sense feed on, are those the re- 
moval of which from the blood is essential for the general 
‘good. Their individual nutritive peculiarities are utilized 
for the welfare of the whole Body. 

‘The Mode of Activity of Secretory Cells. If we con- 
sider the modes of activity of living cells in general, it be- 
comes clear that secretory eclls may produce the specific 
element of a secretion in either of two ways. They may, 
as a by-result of their living play of forces, produce chemi- 
eal changes in the surrounding medium; or they may build 
up certain substances in themsélves and then set them free 
as epecific elements, Yeast, for example, in a saccharine 








266 THE HUMAN BODY. 


solution causes the rearrangement into earbon dioxide, 
alcohol, glycerine and succinic acid, of many atoms of ear- 
bon, hydrogen and oxygen which previously existed as sugar; 
and which during the metamorphosis were probably not 
passed through the living cell. How the latter acts we do 
not know with certainty, but most likely by picking certain 
atoms out of the sugar molecule, and leaving the rest to 
fall down into simpler compounds. On the other hand, we 
find cells forming and storing up in themselves large quan- 
tities of substances, which they afterwards liberate; starch, 
for instance, being formed and laid by in many fruit- 
cells, and afterwards rendered soluble and passed out to 
nourish the young plant. 

Gland-cells might a priori give rise to the specific ele- 
ments of secretions in either of these ways and we have to 
seek in which manner they work. Do they simply act 
as ferments (however that is) upon the surrounding 
medium; or do they form the special bodies which charac- 
terize their secretion, first within their own substance, and 
then liberate them, either disintegrating themselves or 
not at the same time? At present there is alarge and an 
increasing mase of evidence in favor of the second view. 
There is, no doubt, some reason to believe that every living 
cell can act more or less as a ferment upon certain solu- 
tions should they come into contact with it. Not always, 
of course, as an alcoholic ferment, though even as regards 
that one fermentative power it seems very generally pos- 
sessed by vegetable cells, and there is some evidence that 
alcohol is normally produced in small amount (and presum- 
ably by the fermentation of sugar) under the influence of 
certain of the living tissues of the Human Body, As re- 
gards distinctively secretory cells, however, the evidence is 
all the other way, and in many cases we can see the specific 
element collecting in the gland-cells before it is set free in 
the secretion. For example, in the oil-glands of the skin 
(Chap. XX VIL.) we find the secreting cells, at first granular, 
nucleated and protoplasmic, gradually undergoing changes 
by which their protoplasm disappears and is replaced by 
oil-droplets, until finally the whole cell falls to bits and its 





THE ACTION OF GLAND-CELLS. 267 





detritus forms the secretion; the cells being replaced by new 
ones constantly formed within the gland. In such eases 
the secretion is the ultimate product of the cell life; the 
result of degenerative changes of old age occurring in it. 

In other cases, however, the liberation of the specific 
element is not attended with the destruction of the secret- 
ing cell; as an example we may take the pancreas, which | 
is a large gland lying in the abdomen and forming a secre- 
tion used in digestion. Among others, this secretion pos- 
sesses the power, under certain conditions, of dissolving 
proteids and converting them into dialyzable peptones 
(p. 11). ‘This it owes to a specific element known as éryp- 
sin, the formation of which within the gland-cells can be 
traced with the microscope. 

The pancreas, like the majority of the glands connected 
with the alimentary canal, hus an intermittent activity; 
determined by the presence or absence of food in varions 
parts of the digestive tract. If the organ be taken from a 
recently killed dog which has fasted thirty hours and, after 
proper preparation, be stained with carmine and examined 
microscopically, we get specimens of what we may call the 
“resting gland "—a gland which has not been secreting for 
some time, In these it will be seen that the cells lining the 
secreting recesses present two very distinct zones; an outer 
next the basement membrane which does not combine with 
the coloring mutter and is granular, and an inner which is 
not granular but picks up the carmine. The granules we 
shall find to be indications of the presence of a trypsin- 
yielding substance, formed in the cells. 

If another dog be kept fasting until he has # good appe- 
tite and be then allowed to eat as much meat as he will, he 
will commonly take so much that the stomach will only be 
emptied at the end of about twenty hours. This period 
may, so far as the pancreas is concerned, be divided into 
two. From the time the food enters the stomach and on 
for about ten hours, the gland secretes abundantly; after 
that the secretion dwindles, and by the end of the second 
ter hours has nearly ceased. We have, then, a time during 
which the pancreas is working hard, followed by a period 











sl 





268 THE HUMAN BODY. 


in which its activity is very little, but during which it is 
abundantly supplied with food materials. The pancreas 
taken from an animal at the end of the first period and 
prepared for microscopic examination will be found dif- 
ferent from that taken from a dog killed at the end of the 
second digestion period, and also from the resting gland. 
‘Towards the end of the period of uctive work, the gland-cells 
are diminished in size and the proportions of the granular 
and non-granular zones are quite altered. ‘The latter now 
occupies most of the cell, while the granular non-staining 
inner zone is greatly diminished. During the secretion 
there is, therefore, 1 growth of the non-granular and a de- 
struction of the granular zone; and the latter process rather 
exceeding the former, the whole secreting cell is diminished 
in size. During the second digestive period, when secre- 
tion is languid, exactly reverse process takes place. The 
cells increase in size so us to become larger than those of 
the resting gland; and this growth is almost entirely due 
to the granular zone which now occupies most of the cell. 

These facts suggest that during secretion the granular 
part of the cells is used up: but that, simultaneously, the 
deeper non-granular zone, being formed from materials 
yielded by the blood, gradually gives rise to the granular, 
During active secretion the breaking down of the lat- 
ter to yield the specific elements occurs faster than its re- 
generation; in a later period, however, when the secretion 
is ceasing, the whole cell grows and, especially, the granular 
zone is formed faster than it is disintegrated; hence the 
great increase of that part of the cell. If this be so, then 
we ought to find some relationship between the diges- 
tive activity of an infusion or extract of the gland and the 
size of the granular zones of the cells; and it bas been 
shown that such exists; the quantity of trypsin which can 
be obtained from a pancreas being proportionate to the 
size of that portion of its cells. 

‘The trypsin, however, does not exist in the cells ready 
formed, but only a body which yields it under certain cir- 
cumstances, and called zymogen. 

If a perfectly fresh pancreas be divided into halves and 








INFLUENCE OF NERVES ON SEORETION. 269 


one portion immediately minced and extracted with glyce- 
rine, while the other is laid aside for twenty-four hours in 
4 warm place and then similarly treated, it will be found 
that the first glycerine extract has no power of digesting 
proteids, while the second is very active. In other words 
the fresh gland does not contain trypsin, but only some- 
thing which yields it under some conditions; among 
others, on being kept. The inactive glycerine extract of 
the fresh gland is however rich in zymogen: for if a little 
acetic acid be added to it, trypsin is formed and the extract 
becomes powerfully digestive. 

We may then sum up the life of pancreas cell in this 
way. It grows by materials derived from the blood and 
first laid down in the non-granular zone. This latter, in 
the ordinary course of the cell-life, gives rise to the granu- 
lar zone; and in this is a store of zymogen produced by 
the nutritive metabolisms of the cell. When the gland 
secretes, the zymogen is converted into trypsin and set free 
in the secretion; but in the resting gland this transforma- 
tion does not occur. During secretory activity therefore 
the chemical processes taking place in the cell, are different 
from those at other periods; and we have next to consider 
how this change in the mode of life of the cells is brought 
about. 


Influence of the Nervous System upon Secretion. 
When the gland is active it is fuller of blood fl than when at 
rest: its arteries are dilated and its capillaries gorged so 
that it gets a brighter pink color; this extra blood-supply 
might be the primary cause of the altered metabolism. 
Aguin, the activity of the pancreas is under the influence 
of the nervous system, as evinced not only by the reflex 
secretion called forth when food enters the stomach, but 
also by the fact that electrical stimulation of the medulla 
oblongata will canse the gland to secrete. The nervous 
system may, however, only act through the nerves governing 
the calibre of the gland arteries, and so but indirectly on 
the secreting cells; while on the other hand, it is possible 
that nerve-fibres act directly upon the gland-cells and, con- 
trolling their nutritive processes, govern the production of 





210 THE HUMAN BODY. 


the trypsin. To decide between the relative importance of 
these possible agencies we must pass to the consideration of 
other glands; since the question can only be decided by 
experiment upon the lower animals, and the position of 
the pancreas and the difficulty of getting at its nerves with- 
ont such severe operations as upset the physiological condi- 
tion of the animal, furnish obstacles to its study which 
have not yet been overcome, 

Tn certain other glands, however, we find conclusive evi- 
dence of a direct action of nerve-fibres upon the secreting 
elements. If the sciatic nerve of a cat be stimulated elec- 
trically the balls of its feet will sweat. Under ordinary 
circumstances they become at the same time red and full 
of blood; but that this congestion is a factor of subsidiary 
importance as regards secretion is proved by the facts that 
stimulation of the nerve is still able to excite the gland- 
cells and cause sweating in a limb which has been ampu- 
tated ten or fifteen minutes (and in which therefore no cir- 
eulatory changes can occur) and also by the cold sweats, 
with a pallid skin, of phthisis and the death agony. It is, 
however, with reference to the submaxillary and parotid 
salivary glands that our information is most precise, 

When the mouth is empty and the jaws ab rest the sali- 
yary secretion is comparatively small: but a sapid substance 
placed on the tongue will cause a copious flow. The phe- 
nomenon is closely comparable to the production of a reflex 
muscular contraction. A stimulus acting upon an irritable 
tissne excites through it certain afferent nerve-fibres; these 
excite a nerve-centre, which in turn stimulates efferent 
fibres; going to a muscle in the one case, to a gland in the 
other. It will be useful to consider again for a moment 
what occurs in the case of the muscle, taking account only 
of the efferent fibres and the parts they act upon. 

When a muzele in the Body is made to contract reflexly, 
through its nerve, two events occur in it, One is the 
shortening of the muscular fibres; the other is the dilata- 
tion of the muscular arteries; every muscular nerve con- 
tains two sets of fibres, one motor and one vaso-dilator, 
and normally both act together. In this case. however, 








INFLUENCE OF NERVES ON SECRETION. 271 


‘it is clear that the activities of both, though correlated, are 
exentially independent. ‘The contraction is not due to the 

blood-flow for, not only can an excised muscle en- 
tirely deprived of blood, be made to contract by stimulating 
its nerves, but in an animal to which a small dose of curari 
—the arrow poison of certain South American Indians—has 
been given, stimulation of the nerve will cause the vascu- 
lar dilatation but no muscular contraction: the curari par- 
ulyzing the motor fibres, but, unless in large doses, leaving 
the yaso-dilators intact. The muscular fibres themselves 
are quite unacted upon by the poison, as evinced by their 
ready contraction when directly stimulated by an electric 


Now let us return to the salivary glands and see how far 
the facts are comparable. The main nerve of the submax- 
illary gland is known as the chorda tympani, If it be di- 
vided in a narcotized dog, and a tube placed in the gland- 
duct, no saliva will be found to flow. But on stimulating 
the peripheral end of the nerve (that end still connected 
with the gland) an abundant secretion takes place. At 
the same time there is a great dilatation of the arteries of 
the organ, much more blood than before flowing through 
it in a given time: the chorda obviously then contains vaso- 
dilator fibres. Now in this case it might very well be that 
the process was different from that in a muscle, It is con- 
ceivable that the secretion may be but a filtration due to 
imereaged pressure in the gland capillaries, consequent 
on dilatation of the arteries supplying them. If a greater 
filtration into the lymph spaces of the gland took place, this 
liquid might then merely ooze on through the secreting cells 
into the commencing ducts and, as it passed through, dis- 
solve out and carry on from the cells the specific organic 
elements of the secretion. Of these, in the submaxillary 
of the dog at least, mucin is the most important and 
abundant, That, however, the process is quite different, 
and that there are in the gland true secretory fibres in ad- 
dition to the vaso-dilator, just aa in the muscle there are 
true motor fibres, is proved by other experiments. 

If the flow of liquid from the excited gland were merely 








272 THE HUMAN BODY. 


the outcome of a filtration dependent on increased blood: 
pressure in it, then it is clear that the pressure of the 
secretion in the duct could never rise above the pressure in 
the blood-vesscls of the gland. Now it is found, not only 
that the gland can be made to secrete in a recently decapi- 
tated animal, in which of course there is no blood-pressure, 
but that, when the circulation is going on, the pressure of 
the secretion in the duct can rise far beyond that in the 
gland arteries. Obviously, then, the secretion is no ques- 
tion of mere filtration, since a liquid cannot filter against a 
higher pressure. Finally, the proof that the vascular dila- 
tation is quite a subsidiary phenomenon has been com- 
pleted by showing that we can produce all the increased 
blood-flow through the gland without getting any secretion 
—that just as in a muscle nerve we can, by eurari, paralyze 
the motor fibres and leave the vaso-dilators intact, so we 
can by atropin, the active principle of deadly night-shade, 
get similar phenomena in the gland. In an atropized 
animal stimulation of the chorda produces vascular dila- 
tation but not a drop of secretion. Bringing blood to 
the cells abundantly, will not make them drink; we must 
sock something more in the chorda than the vaso-dilator 
fibres—some proper secretory fibres; that the poison acts 
upon them and not upon the gland-cells, is shown, as in 
the muscle, by the fact that the cells still are capable of 
activity when stimulated otherwise than through the 
chorda tympani. For example, by stimulation of the sym- 
pathetic fibres going to the gland. 

So far then we seem to have good evidence of a direct 
action of nerve-fibres upon the gland-cells. But even that 
is not the whole matter, It is extremely probable, if not 
certain, that there are two sets of secretory fibres in the 
gland-nerves: a set which so acts upon the cells as to make 
them pass on more abundantly the transudation elements 
of the secretion (the water and mineral salts), and another, 
quite different, which governs the chemical transformations 
of the cells so.as to make them produce mucin from matters 
previously stored in them, in a comparable way to the pro- 
duction of trypsin from zymogen in the active pancreas, 





INFLUENCE OF NERVES ON SECRETION. 278 





‘These latter fibres may be called “ io,” since they 
directly control the cell metabolism: while the former may 
be called ‘transudatory” fibres. Some of the evidence 
which leads to this conclusion is a little complex, but it is 
worth while to consider it briefly. In the first place, on 
stimulation of the chorda of an unexhausted gland (that ia 
a gland not over-fatigued by previous work) the following 
points can be noted:— 

With increasing strength of the stimulus the quantity of 
the secretion, that is of the water poured out in a unit 
of time, increases; at the same time the mineral salts also 
increase, but more rapidly, so that their percentage in a 
rapidly formed secretion is greater than in a more slowly 
formed, up to a certain limit. The percentage of organic 
constituents of the secretion also increases up to a limit; 
but soon ceases to rise, or even falls again, while the water 
and salts still increase, This of course is readily intelligible; 
since the water and salts can be derived continually from 
the blood, while the specific elements, coming from the 
gland-cells, may be soon exhausted; and so far the experi- 
ment gives no evidence of the existence of distinct nerve- 
fibres for the aults and water, and for the specific elements: 
all vary together with the strength of the stimulus applied 
tothe nerve, But under slightly different circumstances 
their quantities do not run parallel. The proportion of 
specific elements in the secretion is largely dependent on 
whether the gland has been previously excited or not. 
Prior stimulation, not carried on of course to exhaustion, 
largely increases the percentage of organic matters in the 
secretion produced by a subsequent stimulation; but has no 
effect whatever on the quantity of water or salts. These 
ure governed entirely by the strength of the second stimu- 
lation. Here, then, we find that under similar circumstances 
the transudatory and specific elements of the secretion do 
not vary together; and are therefore probably dependent 
upon different exciting causes. And the facts might lead 
us to suspect that there are in the chorda, besides the vaso- 
dilator, two other sets of fibres: one governing the salts 
and water, and the other the specific clements of the seore- 








214 THE HUMAN BODY. 


tion. The evidence is, perhaps, not quite conclusive, but 
experiments upon the parotid gland of the dog put the 
matter beyond a doubt. 

The submaxillary gland receives fibres from the sympa- 
thetic system, as well as the chorda tympani from the 
cerebro-spinal. Excitation of the sympathetic fibres causes 
the gland to secrete, but the saliva poured out is differ- 
ent from that following chorda stimulation, which is 
in the dog abundant and comparatively poor in organic 
constituents, and accompanied by vascular dilatation: while 
the “sympathetic saliva,” as it is called, is leas abundant, 
very rich in mucin, and accompanied with constriction of 
the gland arteries. According to the above view we 
might suppose that the chorda contains many transuda- 
tory and few trophic fibres, and the sympathetic many 
trophic and few transudatory. It might, however, well be 
objected that the greater richness in organic bodies of the 
sympathetic saliva was really due to the small quantity of 
Dlood reaching the gland, when that nerve was stimulated. 
This might alter the nutritive phenomena of the cells and 
cause them to form mucin in unusual abundance, in which 
case the trophic influence of the nerve would be only in- 
direct, Experiments on the parotid preclude this explan- 
ation. That gland like the submaxillary gets nerve-fibres 
from two sources: a cerebral and asympathetic. The latter 
enter the gland along its artery, while the former, origin- 
ating from the glosso-pharyngeal, run in a roundabout 
course to the gland. aulation of the cerebral fibrés 
causes an abundant secretion, rich in water and salts, but 
with hardly any organic constituents. At the same time it 
produces dilatation of the gland arteries, Stimulation of the 
sympathetic causes contraction of the parotid gland arteries 
and no secretion at all. Nevertheless it canses great 
changes in the gland-cells, If it be first stimulated for a 
while and then the cerebral gland-nerve, the resulting 
secretion may be ten times as rich in organic bodies as that 
obtained without previous stimulation of the sympathetic; 
and a similar phenomenon is observed if the two nerves be 
stimulated simultancously. So that the sympathetic nerve, 











INFLUENCE OF NERVES ON SECRETION. 275 


unable of itself to cause a secretion, brings about 
great chemical changes in the gland-cells, It is a distinct 
trophic nerve. This conclusion is confirmed by histology. 
Sections of the gland after prolonged stimulation of the sym- 
pathetic show its cells to be quite altered in appearance, 
and in their tendency to combine with carmine, when com- 
pared cither with those of the resting gland or of the gland 
which has been made to secrete by stimulating its glosso- 
pharyngeal branch alone. 

We have still to meet the objection that the sympathetic 
fibres may be only indirectly trophic, governing the meta~ 
bolism of the cells through the blood-vessels. If this be 
80, cutting off or diminishing the blood-supply of the 
gland, in any way, ought to hare thesame result as stimula- 
tion of its sympathetic fibres. Experiment shows that 
such is not the case and reduces us to a direct trophic influ- 
ence of the nerve. When the arteries are closed und the 
cerebral gland-nerve stimulated, it is found that the per- 
centage of organic constituents in the secretion is as low 
as usual; it remains almost exactly the same whether the 
arteries are open or closed or have been previously open or 
closed. We must conclude that the peculiar influence of 
the sympathetic does not depend upon its vaso-constrictor 
fibres. 


‘These observations make it clear that the phenomena of 
secretion are dependent on very complex conditions, at least 
in the salivary glands and presumably in all others, 
Primarily dependent upon filtration and dialysis from the 
blood-vessels and the physiological character of the gland- 
cells, both of these factors are controlled by the nervous 
ee the secretory tissues being no more automatic than 

muscular; and the facts also give us important evidence 
of power of the nervous system to influence cell nutrition 
directly. 

Summary. By secretion is meant the separation of such 
substances from the blood as are poured out on free surfaces 
of the Body, whether external or internal. In its simplest 
form it is merely a physical process dependent on filtra- 
tion and dialysis; for example, the elimination of carbon 
dioxide from the surfaces of the lungs, and the watery 








276 THE HUMAN BODY. 


liquid poured out on the surfaces of the serous membranes. 
Such secretions are known as ¢ransudata and their amount 
is only indirectly controlled by the nervous system, through 
the influence of the latter upon the circulation of the blood. 
‘The cells lining such surfaces are not secretory tissues in 
any true sense of the word, being merely flat, inactive, thin 
scales protecting the surfaces. In other cases the lining 
cells are thicker, and actively concerned in the process; they 
are then usually spread over the recesses of a much folded 
membrane, so that the whole is rolled up into a compact 
organ called a gland, the secretion of which may contain 
only transudation elements (aa for example that of the 
lachrymal glands which form the tears) or may contain a 
specific element, formed in the gland by its cells, in addition 
to transudation elements, In either case the activity of 
the organ is directly influenced by the nervous system, 
usually in a reflex manner (¢.g. the watering of the eyes 
when the eyeball is touched and the saliva poured into the 
mouth when food is tasted) but may also be otherwise ex- 
cited, as for example the flow of tears under the influence 
of those changes of the central nervous system which are 
associated with sad emotions, or the watering of the mouth 
at the thought of dainty food. The nerves going to such 
glands, besides controlling their blood-vessels, act upon the 
gland-cells; one set governing the amount of transudation 
of water and salines which shall take place through them, 
and another (in the case of glands producing secretions 
with one or more specific elements) controlling the produc- 
tion of these, by starting new chemical processes in the cells 
by which a substance built up in them during rest is con- 
verted into the specific element, which is soluble in and 
carried off by the transudation elements. What the speci- 
fic element of gland shall be, or whether its secretion con- 
tain any, is dependent on the nature of its special cells; 
how much transudation and how much specific clement 
shall be secreted at any time is controlled by the nervous 
system; just as the contractility of a muscle depends on 
the endowments of muscular tissue, and whether it shall 
rest or contract—and if the latter how powerfully—upon 
its nerve. 


CHAPTER XIX. 


THE INCOME AND EXPENDITURE OF THE 
BODY. 


‘The Material Losses of the Body. All day long while 
life lasts each of us is losing something from his Body. 
‘The air breathed into the lungs becomes in them laden 
with carbon dioxide and water vapor, which are carried off 
with it when it is expired. The skin is as constantly giv- 
ing off moisture, the total quantity in twenty-four hours 
being a good deal, even when the amount passed out at any 
‘one time is 50 small as to be evaporated at once and go docs 
not collect as drops of visible perspiration. The kidneys 
again are constantly at work separating water and certain 
crystalline nitrogeneous bodies from the blood, along with 
some mineral salts. The product of kidney activity, how- 
ever, not being forthwith carried to the surface but to 
a reservoir, in which it accumulates and which is only 
emptied at intervals, the activity of those organs appears 
at first sight intermittent. If to these loases we add cer- 
tain other waste substances added to the undigested residue 
of the food passed out from the alimentary canal, and the 
loss of hairs and of dried cells from the surface of the skin, 
it is clear that the total amount of matter removed from 
the Body daily is considerable. The actual quantity varies 
with the individual, with the work done, and with the 
nature of the food eaten; but the following table gives 
approximately that of the more important daily material 
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THE DAILY LOSSES OF THE BODY. 279 


The living Body thus loses daily in round numbers 4 
kilograms of matter (8 Ibs.) and, since it is unable to 
create new matter, this loss must be compensated for from 
the exterior or the tissues would soon dwindle away alto- 
gether; or at least until they were so impaired that life 
camoto anend. After death the losses would be of a differ- 
ent kind, and their quantity much more dependent upon 
surrounding conditions; but except under very unusual 
circumstances the wasting away would still continue in the 
dead Body. Finally, the composition of the daily wastes 
of the living Body is tolerably constant; it doea not simply 
lose a quantity of matter weighing so much, but a certain 
amount of definite kinds of matter, carbon, nitrogen, oxygen, 
and so on; and these same substances must be restored to 
it from outside, in order that life may be continued. To 
give one asking for bread astone might, no doubt, if it were 
swallowed, compensate in weight for the matter he lost in 
twenty-four hours; but bread would be needed to keep 
him alive, In other words, the Body not only requires a 
supply of matter from outside, but a supply of certain 
definite kinds of matter. 

‘The Losses of the Body in Energy. The daily expendi- 
ture of matter by the living Body is not the only one: as 
continuously it loses in some form or another energy, or 
the power of doing work; often as mechanical work ox- 
pended in moving external objects, but even when at rest 
enorgy is constantly being lost to the Body in the form of 
heat, by radiation and conduction to surrounding objects, 
hy the evaporation of water from the Jungs and skin, and 
by removal in warm excretions. Unless the Body can 
make energy it must therefore receive a certain supply of 
it also from the exterior, or it would very soon cease to 
carry on any of its vital work; it would be unable to 
move and would cool down to the temperature of eurround- 
ing objects. The discoveries of this century having shown 
that energy is as indestructible and unereatable (see Phy- 
sics) as matter, we are led to look for the sources of the 
supply of it to the Body; and finding that the living Body 
daily receives it and dies when the supply is cut off, we no 








280 THE HUMAN BODY. 


longer suppose, with the older physiologists, that it works 
by means of a mysterious vital force existing in or created 
by it; but that getting energy from the outside it utilizes 
itforits purposes—for the performance of its nutritive and 
other living work—and then returns it to the exterior 
in what the physicists know as a degraded state; that is in 
a less utilizable condition. While energy like matter is in- 
destructible it is, unlike matter, transmutable; iron is always 
iron and gold always gold; neither can by any means which 
we possess be converted into any other form of matter; and 
so the Body, needing carbon, hydrogen, oxygen, and nitro- 
gen to build it and to cover its daily losses, must be sup- 
plied with those very substances. As regards energy this 
is not the case, While the total amount of it in the uni- 
verse is constant, its form is constantly subject to change— 
and that one in which it enters the Body need not be that 
in which it exists while in it, nor that in which it leaves it. 
Daily losing heat and mechanical work the Body does not 
need, could not in fact much utilize energy, supplied to it 
in these forms; but it does need energy of some form and 
in amount equivalent to that which it loses, 

The Conservation of Enorgy, The forms of energy 
known to us are not nearly so numerous as the kinds of 
matter. Still we all know several of them; such as light, 
heat, sound, electricity, and mechanical work; and most 
people nowadays know that some of these forms are inter- 
convertible, so that directly or indirectly we can turn one 
into another. In such changes it is found that a definite 
amount of one kind always disappears to give rise to a 
certain quantity of the other; or, in other words, that so 
much of the first form is equivalent to so much of the 
second. In a steam-engine, heat is produced in the fur- 
nace; when the engine is at work all of this energy does 
not leave it as heat; some goes as mechanical work, and the 

. more work the engine docs the greater is the difference bo- 
tween the heat generated in the furnace and that leaving 
the machine. If, however, we used the work for rubbing 
two rough surfaces together we could get the heat back 
again, and if (which of course is impossible in practice) 





THE GONSERVATION OF ENERGY. 281 


we could avoid all friction in the moving paris of the 
machine, the quantity thus restored would be exactly equal 
to the excess of the heat generated in the furnace over that 
leaving the engine. Having turned some of the heat into 
mechanical work we could thus turn the work back into 
heat again, and find it yield exactly the amount which 
seemed lost. Or we might use the engine to drive an elec 
tro-magnetic machine and so turn part of the heat liber- 
ated in its farnace first into mechanical work and this into 
electricity; and if we chose to use the latter with the 
proper apparatus, we could turn more or less of it into 
light, and so have a great part of the energy which first 
became conspicuous as heat in the engine furnace, now 
manifested in the form of light at some distant point. In 
fact, sturting with a given quantity of one kind of energy, 
we may by proper contrivances turn all or some of it into 
one or more other forms; and if we collected all the final 
forms and retransformed them into the first, we should 
have exactly the amountof it which had disappeared when 
the other kinds appeared. ‘This law, that energy can 
change its form but that its amount is invariable, that it 
cannot be created or destroyed but simply transmuted, is 
known as the /aw of the Conservation of Energy (sce Phy- 
sics), and, like the indestructibility of matter, lies at the 
basis of all scientific conceptions of the universe, whether 
concerned with animate or inanimate objects. 

Since all forms of energy are interconvertible it is con- 
venient in comparing amounts of different kinds to oxpress 
thein in terms of some one kind, by saying how much of 
that standard form the given amount of the kind spoken 
of would give rise to it were all converted into it. Since 
the most easily measured form of energy is mechanical 
work this is commonly taken as the standard form, and 
the quantities of others are expressed by saying how great 
a distance against the force of gravity at the earth's sur- 
face a given weight could be raised by the energy in ques- 
tion, if it were all spont in lifting the weight. ‘The units 
of mechanical work being the kilogrammoetor, or the foot- 
pound, the mechanical equivalent of any given kind of energy 








232 THE HUMAN BODY. 


isthe number of kilogrammeters or foot-pounds of work its 
unit quantity would perform, if converted into mechanical 
work and used to raise a weight. For example the unit 
quantity of heat is that necessary to raise one kilogram of 
water one degree centigrade in temperature; or sometimes, 
in books written in English, the quantity necessary to warm 
one pound of water one degree Fahrenheit. When there- 
fore we say that the mechanical equivalent of heat is 423 
kilogrammeters we mean that the quantity of heat which 
would raise one kilogram of water in temperature from 
4° ©. to 5° C. would, if all turned into mechanical work, 
be able to raise one kilogram 423 meters against the attrac- 
tion of the earth; and conversely that this amount of me- 
chanical work if turned into heat would warm a kilogram 
of water one degree centigrade. ‘The mechanical equiva- 
lent of heat, taking the Fahrenheit thermometric scale and 
using feet and pounds as measures, is 772 foot-pounds. 
Potential and Kinetic Energy. At times energy seems 
to be lost. Ordinarily we only observe it when it is doing 
work and producing some change in matter: but sometimes 
it is at rest, stored away and producing no changes that 
we recognize and thus seems to have been destroyed. 
Energy at work is known as kinetic energy; energy at rest, 
not producing changes in matter, is called potential energy. 
Suppose a stone pulled up by a string and left suspended 
in the air. We know a certain amount of energy was 
used to lift it; but while it hangs we haye neither heat nor 
light nor mechanical work to represent it. Still the energy 
is not lost; we know we have only to ent the string and 
the weight will fall, and striking something give rise to 
heat. Or we may wind up a spring and keep it so by a 
catch. In winding it up a certain amount of energy in 
the form of mechanical work was used to alter the form 
of the spring. Until the catch is removed this energy re- 
mains stored away as potential energy: but we know it is 
not lost. Once the spring is let loose again it may drive a 
clock or a watch, and in so doing will perform again just 
s0 much work as was spent in coiling it; and when the 
watch has ran down this energy will all have been turned 





POTENTIAL ENERGY OF CHEMICAL AFFINITY. %83 


into other forms—mainly heat developed in the friction of 
the parts of the watch against one another: but partly also 
in producing movements of the air, a portion of which we 
ean readily observe in the sound of its ticking. The law 
of the conservation of energy doos not say, then, that either 
the total potential or the total kinetio energy in the universe 
is constant in amount: but that the sum of the two is inva- 
riable, while constantly undergoing changes from kinetic 
to potential and vice versa: and from one form of kinetic 
to another. 

‘The Energy of Chemical Affinity. Between every two 
chemical atoms which are capable of entering into combi- 
nation there exists a certain amount of potential energy: 
when they unite this energy is liberated, usually in the form 
of heat, and once they have combined a certain amount of 
kinetic energy must be spent to pull them apart again; this 
being exactly the amount which was liberated when they 
united. The more stable the compound formed the more 
kinetic energy appears during its formation, and the more 
must be spent to break it up again. One may imagine the 
separated atoms as two balls pushed together by springs, 
the strength of the spring being proportionate to the de- 
gree of their chemical affinity. Once they are let loose 
and permitted to strike together the potential energy pre- 
viously represented by the compressed springs disappears, 
and in its place we have the kinetic energy, represented by 
the heat developed when the balls strike together, To 
pull them apart again, against the springs, to their original 
positions, just so much mechanical work must be spent as 
is the equivalent of that amount of heat which appeared 
when they struck; and thus kinetic energy will again be- 
come latent in breaking up the compound represented by 
the two in contact. Tho energy liberated in chemical com- 
bination is the most important source of that used in our 
machines: and also of that spent by the living Body. 

‘The Relation between the Matters Removed trom the 
Body daily and the Energy Spent by it. A working 
locomotive is, we know, constently losing matter to the 
exterior in the form of ashes and gaseous products of com- 








284 TRE HUMAN BODY. 


bustion, the Jatter being mainly carbon dioxide anc water 
vapor, The engine also expends energy, not only in the 
form of heat radiated to the air, but as mechanical work 
in drawing the cars against the resistance offered by fric- 
tion or sometimes, up an incline, by gravity. Now the en- 
gine-driver knows that there is a close relationship between 
the losses of matter and the expenditure of energy, so that 
he has to stoke his furnace more frequently and allow a 
greater draft of air through it in going up a gradient 
than when running on the level. The more work the en- 
gine does the more coals and air it needs to make up for 
its greater waste. If we seek the cause of this relation- 
ship between work and waste, the first answer naturally is 
that the engine is a machine the special object of which is 
to convert heat into mechanical work, and so the more 
work it has to do the more heat is required for conversion, 
and consequently the more coals must be burnt. This, 
however, opens the question of the source of the heat—of 
all that yast amount of kinetic energy which is liberated in 
the furnace; and to answer this we must consider in what 
forms matter and energy enter the farnace, since the 
onorgy liberated there must be carried in somehow from 
outside. For present purposes couls may be considered as 
consisting of carbon and hydrogen, both of which sub- 
stances tend to forcibly combine with oxygen at high tem- 
peratures, forming in the one case carbon dioxide and in 
the other water. The oxygen necessary to form these com- 
pounds being supplied by the air entering the furnace, all 
the potential energy of chemical affinity which existed be- 
tween the uncombined clements becomes kinetic, and is 
liberated as heat when the combination takes place. The 
energy utilized by the engine is therefore supplied to it in 
the form of potential energy, associated with the nneom- 
bined forms of matter whicu reach the furnace. Once the 
carbon and hydrogen have combined with oxygen they are 
no longer of any use as liberators of energy; and the com- 
pounds formed if retained in the furnace would only clog 
it and impede farther combustion; they are therefore got 
rid of as wastes through the smoke-stack. The engine, 








SOURCES OF ENERGY. 285 


in short, receives uncombined elements associated with 
potential energy; and loses combined clements (which have 
lost the energy previously associated with them) and kinetic 
energy: it so to speak separates the energy from the mat- 
ter with which it was connected and, utilizing it, gets rid 
of the exhausted matter. The amount of kinetic energy 
liberated during such chemical combinations is very great; 
a kilogram of carbon uniting with oxygen to form car- 
bon dioxide sets free 8080 units of heat, or calories. Dur- 
ing the combination of oxygen and hydrogen to form 
water even more energy is liberated, one kilogram of hydro- 
gen when completely burnt liberating more than thirty-four 
thousand of the same units. The mechanical equivalent 
of this can be calculated if. it is remembered that one heat 
unit = 423 kilogrammeters, 

Turning now to the living Body we find that its income 
and expenditure agree very closely with those of the steam- 
engine, It receives from the exterior substances capable 
of entering into chemical union; these combine in it and 
liberate energy; and it loses kinetic energy and the products 
of combination. From the outside it takes oxygen through 
the lungs, and oxidizable substances (in the form of foods) 
through the alimentary canal; these combine under the 
conditions prevailing in the living cells just as the carbon 
and oxygen, which will not unite at ordinary temperatures, 
combine under the conditions existing in the furnace of 
the engine; the energy liberated is employed in work of the 
Body, while the uscless products of combination are got 
rid of. ‘Lo explain, then, the fact that our Bodies go on 
working we have no need to invoke some special mysterious 
power resident in them and capable of creating energy, a 
wital force having no relation with other natural forces, 
such as the older physiologists used to imagine. The Body 
needs and gets a supply of energy from the exterior just as 
the steam-engine does, food and air being to one what coals 
and air are to the other; each is a machine in which energy 
is liberated by chemical combinations and then used for 
special work; the character of which depends upon the 
peculiarities of mechanism which utilizes it in each case, 








286 THE HUMAN RODY. 


and not upon any peculiarity in the energy utilized or in 
ite source. The Body is, however, a far more economical 
machine than any steam-engine; of all the energy liberated 
in the latter only a small fraction, about one eighth, is use- 
fully employed, while our Bodies can utilize for the perform- 
ance of muscular work alone one fifth of the whole energy 
supplied to them; leaving out of account altogether the 
nutritive and other work carried on in them, and the heat 
lost from them. 

The Conditions of Oxidation in the Living Body. Al- 
though the general principles upon which the Body and 
the steam-engine get their working power are the same, 
still in minor points very obvious differences are found 
between them. In the first place the coals of un engine 
are oxidized only at a very high temperature, one which 
would be instantly fatal to our Bodies which, although 
warm when compared with the bulk of inanimate objects, 
are very slow fires when compared with a furnace. Chem- 
istry and physics, however, teach us that this difference is 
quite unimportant so far as concerns the amonnt of energy 
liberated. If magnesium wire be ignited in the air it will 
become white-hot, flame, and leave at the end of a few 
seconds only a certain amount of incombustible rust or 
magnesia, which consists of the metal combined with 
oxygen. The heat and light evolved in the process repre- 
sent of course the energy which, in a potential form, was 
associated with the magnesium and oxygen before their 
combination. We can, however, oxidize the metal ina differ- 
ont way, attended with no evolution of light and no very per- 
coptible rise of temperature. If, for instance, we leave it in 
the air it will become gradually turned into magnesia with- 
out having ever been hot to the touch or luminous to the 
eye. ‘The process will, however, take days or weeks; and 
while in this slow oxidation just as much energy is liberated 
as in the former case it now all takes the form of heat; and 
instead of being liberated in a short time is spread over a 
much longer one, as the gradual chemical combination takes 
place. The slowly ox: ig Magnesium is, therefore, at no 
moment noticeably hot since it loses its heat to surrounding 





SOURCE OF BODILY RNERGY. 287 


objects az fast as it is generated. The oxidations occurring 
in our Bodies are of this slow kind. An ounce of arrow- 
soot oxidized in # fire, and in the Human Body, would 
liberate exactly as much energy in one case as the other, 
but the oxidation would take place in a few minutes and 
ata high temperature in the former, and slowly, at a lower 
temperature, in the latter. In the second place, the engine 
differs from the living Body in the fact that the oxidations 
in it all take place in a small area, the furnace, and so the 
temperature there becomes very high; while in our Bodies 
the oxidations take place all over, in each of the living 
cells; there is no one furnace or hearth where all the energy 
is liberated for the whole and transferred thence in one 
form or another to distant parts: and this is another reason 
why no one part of the Body attains a very high temperature, 

Tho Fuel of the Body. ‘This is clearly different from 
that of an ordinary engine: no one could live by eating 
coals, This difference again is subsidiary; a gas-engine 
requires different fael from an ordinary locomotive; and 
the Body requires a somewhat different one fromeither. It 
needs as foods, substances which can, in the first place, be 
absorbed from the alimentary canal and carried to the 
various tissues; and, in the second, can there be oxidized 
at a low temperature or, perhaps more probably, can be 
converted by the living cells into compounds which can be 
so oxidized. With some trivial exceptions, all substances 
which fulfill these conditions are complex chemical com- 
pounds, and to understand their utilization in the Body 
we must extend a little the statements above made as to the 
liberation of energy in chemical combinations, The general 
law may be stated thus—Hnergy is liberated whenever chemi- 
cal union takes place: and whenever more stable compounds 
are formed from less stable ones, in which the constituent 
atonis were less firmly held together. Of the liberation by 
simple combination we have already seen an instance in the 
oxidation of carbon in a furnace: but the union need not 
be an oxidation. Everyone knows how hot quicklime 
becomes when it is slaked; the water combining strongly 
with the lime, and energy being liberated in the form of 





288 THe HUMAN BODY. 





heat, during the process, Of the liberation of energy by 
the breaking down of a complex compound, in which the 
atoms are only feebly united, into simpler and stabler ones, 
we get an example in alcoholic fermentation. During that 
process grape sugar is broken down into more stable com- 
| pounds, mainly carbon dioxide and alcohol, while oxygen 
is at the same time taken up. To pull apart the carbon, 
hydrogen and oxygen of the sugar molecule requires a cer- 
tain expenditure of kinetic energy: but in the simultaneous 
formation of the new and stabler compounds a greater 
amount of energy is set free, and the difference appears as 
heat, so that the brewer has to cool his vats with ice. It 
is by processes like this latter, rather than by direct com- 
binations, that most of the kinetic energy of the Body is 
obtained; the complex proteids and fats and starches and 
sugar taken as food being broken down (usually with con- 
.  comitant oxidation) into simpler and more stable com- 
pounds, : 
Oxidation by Successive Steps. In the furnace of an 
engine the oxidation takes place completely at once. The 
carbon and hydrogen leaving it, if it is well managed, aro 
each in the state of their most stable oxygen compound. 
But this need not be so: we might first oxidize the carbon 
80 ag to form carbon monoxide, OO, and get a certain 
amount of heat; and then oxidize the carbon monoxide 
farther so as to form carbon dioxide, COs, and get more 
heat. If we add together the amounts of heat liberated in 
each stage, the sum will be exactly the quantity which would 
have been obtained if the carbon had been completely burnt 
to the state of carbon dioxide at first. Every one who has 
stndied chemistry will think of many similar cases. As 
the process is important physiologically we may take an- 
other example; say the oxidation of alcohol. This may be 
burnt completely and directly, giving rise to carbon dioxide 
and water— 


CHO +O = 200, + 3h0 


TAlcohol. 6 Oxygen. 2 Carbon dioxide, 3 water, 


But instead of this we can oxidize the alcohol by stages, 


il 




















OTILIZATION OF ENERGY IN:THE BODY. 289 


getting at each stage only a comparatively small amount of 
heat evolved. By combining it first with one atom of oxy- 
gon, we get aldehyde and water— 

CHO + 0 = GHO + HO 

Alcohol, 10xyyen, 1 Aldehyde. 1 Water. 
"Then we add an atom of oxygen to the aldehyde and get 
neetic acid (vinegar)— 

OHO + 0 = OHO: 
1 Aldehyde. 1 Oxygen. 1 Acetic acid. 

And finally we may oxidize the acetic acid so as to get car- 
bon dioxide and water— 


C:HiO: + O. = 200: + 210 


We get, in either case, from one molecule of alcohol, two of 
carbon dioxide and three of water; and six atoms of oxygen 
are tuken up. In each stage of the gradual oxidation a 


certain amount of heat is evolved; and the sum of these is 
exactly the amount which would have been evolved by 
burning the alcohol completely at once. 

The food taken into the Body is for the most part oxi- 
dized in this gradual manner; the products of imperfect 
combustion in one set of cells being carried off and more 
completely oxidized in another set, until the final pro- 
ducts, no longer capable of further oxidation in the Body, 
are carried to the lungs, or kidneys, or skin, and got rid of. 
A great object of physiology is to trace all intermediate 
compounds between the food which enters and the waste 
products which leave; to find out just how far chemical 
degradation is carried in each organ; and what substances 
are thus formed in various parts: but at present this part 
of the science is very imperfect. 

‘The Utilization of Energy in the Living Body. In the 
steam-engine energy is liberated as heat; some of the heat 
is used to evaporate water and expand the resulting steam; 
and then the steam to drive a piston. But in the living 
Body it is very probable (indeed almost certain) that a 
great part of the energy liberated by chemical transfor- 








200 THE HUMAN BODY. 


mations does not first take the form of heat; though some 
of it does. This, again, does not affect the general prin- 
ciple: the source of energy is essentially the same in both 
causes; it is merely the form which it takes that is dif- 
ferent. In a galvanic cell energy is liberated during the 
union of zine and sulphuric acid, and we may so arrange 
matters as to get this energy as heat; but on the other 
hand we may lead it off, as a so-called gulvanic current, 
and nse it to drive a magneto-electric machine before it 
has taken the form of heat at all. In fact, that heat may 
be used to do mechanical work we must reduce some of it 
to a lower temperature: an engine needs a condenser of 
some kind as well as a furnace; and, other things being 
equal, the cooler the condenser the greater the proportion 
of the whole heat liberated in the furnace which can be 
used to do work. Now in a muscle there is no condenser; 
its temperature is uniform throughout. So when it contracts 
and lifts a weight, the energy employed must. be liberated 
in some other form than heat—some form which the mnscu- 
lar fibre can use without a condenser. 

Summary. The living Body is continually losing mat- 
ter and expending energy. So long as we regard it as 
working by virtue of some vital force, the power of gener- 
ating which it has inherited, the waste is dificult to 
account for, since it is far more than we can imagine as due 
merely to wear and tear of the working parts, When, 
however, we consider the nature of the income of the Body, 
and of its expenditure, from a chemico-physical point of 
view, we get the clue to the puzzle. The Body docs not 
waste because it works but works because it wastes. The 
working power is obtained by chemical changes occurring 
in it, associated with the liberation of energy which the 
living cells utilize; and the products of these chemical 
changes, being no longer available as sources of energy, are 
passed out. The chemical changes concerned are mainly 
the breaking down of complex and unstable chemical com- 
pounds into simpler and more stable ones, with concomi- 
tant oxidation. Accordingly the material losses of the 








SOURCES OF ENERGY IN THE BODY. 291 


' Body are highly or completely oxidized, tolerably simple 
chemical compounds; and its material income is mainly 
uncombined oxygen, and oxidizable substances, the former 
obtained through the lungs, the latter through the alimen- 
tary canal. In energy, its income is the potential energy 
of uncombined or fecbly combined elements, which are 
capable of combining or forming more stable combinations; 
and its final expenditure, is kinetic energy almost entirely 
in the form of mechanical work and heat. Given oxygen, 
all oxidizable bodies will not serve to keep the Body alive 
and working, but only those which (1) are capable of ab- 
sorption from the alimentary canal and (2) those which are 
oxidizable at the temperature of the Body under the influ- 
ence of protoplasm. Just as carbon and oxygen will not 
unite in the farnace of an engine unless the “fire be 
lighted” by the application of a match but, when once 
started, the heat evolved at one point will serve to carry on 
the conditions of combination through the rest of the mass, 
so the oxidations of the Body only occur under special con- 
ditions; and these are transmitted from parent to offspring. 
Every new Human Being starts as a portion of protoplasm 
separated from a parent and affording the conditions for 
those chemical combinations which supply to living matter 
its working power: this serves, like the energy of the 
burning part of a fire, to start similar processes in other 
portions of matter. At present we know nothing in physi- 
ology answering to the match which lights a furnace; those 
manifestations of energy which we call life are handed 
down from generation to generation, as the sacred fire in 
the temple of Vesta from one watcher to another. Science 
may at some time teach us how to bring the chemical con- 
stituents of protoplasm into that combination in which 
they possess the faculty of starting oxidations under 
those conditions which characterize life; then we will have 
learnt how to strike the vital match. For the present 
we must be ent to study the properties of that form 
of matter which possesses living faculties; since there is no 
satisfactory Seek that it has ever been produced, within 














292 THE HUMAN BODY. 


our experience, apart from the influence of matter already 
living. How the vital spark first originated, how mole- 
cules of carbon, hydrogen, nitrogen and oxygen first united 
with water and salts to form protoplasm, we have no scien- 
tifie data to ground a positive opinion upon, and such as we 
may have must rest upon other grounds. 





CHAPTER XX. 
FOODS. 


Foods as Tissue Formers, Hitherto we have considered 
foods merely as sonrces of energy, but they are also re- 
quired to build up the substance of the Body. From birth 
to manhood we increase in bulk and weight, and that, not 
merely by accumulating water and such substances, but by 
forming more bone, more muscle, more brain, and so on, 
from materials which are not necessarily bone or muscle 
or nerve tissue. Alongside of the processes by which com- 
plex substances are broken down and oxidized and energy 
liberated, constructive processes take place by which new 
complex bodies are formed from simpler substances taken 
as food. A great part of the energy liberated in the Body is 
in fact utilized first for this purpose, since to construct com- 
plex unstable molecules, like those of protoplasm, from the 
simpler compounds taken into the Body, needs an expendi- 
ture of kinetic energy. Even after full growth, when the 
Body ceases to gain weight, the came synthetic processes go 
on; the living tissues are steadily broken down and con- 
stantly reconstructed, as we see illustrated by the condition 
of a man who has been starved for some time, and who loses 
not only his power of doing work and of maintaining his 
bodily temperature but also a great part of his living tissues. 
If aguin fed properly he soon makes new fat and new muscle 

“and regains his original mass. Another illustration of the 
continuance of constructive powers during the whole of life 
is afforded by the growth of the muscles when exercised 
properly. 

Since the tissues, on ultimate analysis, yield mainly car- 
bon, hydrogen, nitrogen and oxygen, it might be supposed 
@ priori that a supply of these elements in the uncombined 








204 THE HUMAN BODY. 


state would serve as muterial for the constructive forces of 
the Body to work with. Experience, however, teaches ux 
that this is not the case, but that the animal body requires, 
for the most part, highly complex compounds for the con- 
struction of new tissue elements. All the active tissues 
yield on analysis large quantities of proteids which, us 
pointed ont in Chapter I., enter always into the structure of 
protoplasm. Now, so far as we know at present, the animul 
body is unable to build up proteids from simpler com- 
pounds of nitrogen, although when given one variety of 
them it can convert that one into others, and combine them 
with other things to form protoplasm. Hence proteids are 
an essential article of diet, in order to replace that portion 
of the living cells which is daily broken down and elimi- 
nated in the form of urea and other waste substances. 
Even albuminoids (p. 11), although so nearly allied to pro- 
teids, will not serve to replace them entirely in a diet; a 
man fed abundantly on gelatin, fats, and starches, would 
starve as certainly, though not so quickly, as if he got no 
nitrogenous food at all; his tissue waste would not be made 
good, and he would at last be no more able to utilize the 
energy-yielding materials supplied to him, than a worn-out 
steam-engine could employ the heat of a fire in its furnace. 
So, too, the animal is unable to take the carbon for the 
construction of its tissues, from such simple compounds as 
carbon dioxide. Its constructive power is limited to the 
utilization of the carbon contained in more complex and 
less stable compounds, snch as proteids, fats, or sugars. 
The main bulk of all useful foods must therefore be 
made up of complex substances, and of these a part must 
be proteids, since the Body can utilize nitrogen for tissue 
formation only when supplied with it in that form. The 
bodies thus taken in are sooner or later broken down intue 
simpler and eliminated; some at once in order to yield 
energy, others only ufter haying first been built up into 
part of a living cell. The partial exceptions afforded by 
such losses to the Body as milk for enckling the young, 
or the albuminous and fatty bodies stored for the same 
purpose in the egg of a bird, are only apparent; the chemi- 


FOOD OF PLANTS. 295 


cal degradation is only postponed, taking place in the body 
of the offspring instead of that of the parent. In all cases 
animals are thus, essentially, proteid consumers or wasters, 
and breakers down of complex bodies; the carbon, hydro- 
gen and nitrogen which they take as foods in the form of 
complex unstable bodies, ultimately leaving them in the 
simpler compounds, carbon dioxide, water, and urea; 
which are incapable of either yielding energy or building 
tissne for any other animal and so of serving it as food. 
The question immediately suggests itself, How, since animals 
are constantly breaking up these complex bodies and can- 
not again build them, is the snpply kept up? For exam- 
ple,the supply of proteids, which cannot be made artificially 
by any process which we know, and yet are necessary foods 
for all animals, and daily destroyed by them. 

Tho Food of Plants. As regurds our own Bodies the 
question at the end of the last paragraph might perhaps be 
answered by saying that we get our proteids from the flesh 
of the other animals which we eat. But, then, wo have to 
account for the possession of them by those animals; since 
they cannot make them from urea and carbon dioxide and 
water any more than we can. The animals eaten get thom, 
in fact, from plants which are the great proteid formers of 
the world, so that the most carnivorous animal really de- 
pends for its most essential foods upon the vegetable king- 
dom; the fox that devours a hare in the long run lives on 
the proteids of the herbs that the hare had previously oaten, 
All animals are thus, in a certain sense, parasites; they 
only do half of their own nutritive work, just the final 
stages, leaving all the rest to the vegetable kingdom and 
using the products of its labor; and plants are able to meet 
this demand because they can live on the simple compounds 

. of carbon, hydrogen, and nitrogen climinated by animals, 
building up out of them new complex substances which 
animals can use as food. A green plant, supplied with am- 
monia salts, carbon dioxide, water, and some minerals, will 
grow and build up large quantities of proteids, fats, starches, 
and similar things; it will pull the stable compounds eli- 
minated by animals to pieces, and build them up into com- 








296 THE HUMAN BODY. 


plex unstable vodies, capable of yielding energy when again 
broken down. However, to do such work, to break up 
stable combinations and make from them less stable, needs 
asupply of kinetic energy, which disappears in the process 
being stored away as potential energy in the new compound; 
and we may ask whence it is that the plant gets the supply 
of energy which it thus utilizes for chemical construction, 
since its simple and highly oxidized foods can yield it none. 
Tt has been proved that for this purpose the green plant 
uses the energy of sunlight: those of its cells which contain 
the substance called chlorophyl (leaf green) have the power 
of utilizing energy in the form of light for the perform- 
ance of chemical work, just as a steam-engine can utilize 
heat for the performance of mechanical work. Exposed to 
light, and receiving carbon dioxide from the air, and water 
wnd ammonia (which is produced by the decomposition of 
urea) from the soil, the plant builds them up again, with 
the elimination of oxygen, into complex bodies like those 
which animals broke down, with fixation of oxygen. 
Some of the bodies thus formed it uses for its own growth 
and the formation of new protoplasm, just as an animal 
does; but in sunlight it forms more than it uses, and the 
excess stored up in its tissues is used by animals. In the 
long run, then, all the energy spent by our Bodies comes 
through millions of miles of space from the sun; but to 
seek the source of its supply there would take us far out of 
the domain of Physiology (see Astronomy). 
Non-Oxidizable Foods. Besides our oxidizable foods, it 
large number of necessary food materials are not oxidiza- 
ble, or at least are not oxidized in the Body, Typical in- 
stances are afforded by water and common galt. The use 
of these is in great part physical: the water, for instance, 
dissolves materials in the alimentary canal, and carries the 
solutions through the walls of the digestive tube into 
the blood and lymph vessels, so that they can be carried 
from part to part; and it permits interchanges to go on by 
diffusion. The salines also influence the solubility and 
chemieal interchanges of other things present-with them. 
Serum albumen, the chief proteid of the blood, for example, 








NON-OXIDIZABLE FOODS, 297 


is insoluble in pure water, but dissolves readily if a small 
quantity of neutral salts is present. Besides such uses the 
non-oxidizable foods have probably others, in what we may 
call machinery formation. In the salts which give their 
hardness to the bones and teeth, we haye an example of 
such an employment of them: and to a less extent the 
same may be true of other tissues. The Body, in fact, is 
not a mere store of potential energy but something more— 
it is a machine for the disposal of it in certain ways; and, 
wherever practicable, it 18 clearly advantageous to have the 
purely energy-expending parts made of non-oxidizable mat- 
ters, and so protected from change and the necessity of 
frequent renewal. The Body is a self-building and self- 
repairing machine, and the material for this building and 
repair must be supplied in the food, as well as the fuels, or 
oxidizable foods, which yield the energy the machine ex- 
pends; and while experience shows us, that even for ma- 
chinery construction, oxidizable matters are largely needed, 
nevertheless it isa gain to replace them by non-oxidizable 
substances when possible; just as if practicuble it would be 
advantageous to construct an engine ont of materials which 
would not rust, although other conditions determine the 
use of iron for the greater part of it. 

Definition of Foods. Foods may be defined as sub- 
stances which are taken into the alimentary canal, and 
which, when absorbed from it, serve either to supply material 
for the growth of the Body, or for the replacement of matter 
which has been removed from it, either after oxidation or 
without having been oxidized. Foods to replace matters 
which have been oxidized must be themselves oxidizable; 
they are force generators, but may be and generally are also 
tissue formers; dnd ure nearly always complex organic sub- 
stances derived from other animals or from plants. Foods 
to replace matters not oxidized in the Body are force regu- 
lators, and are for the most part tolerably simple inorganic 
compounds, Among the force regulators we must, how- 
eyer, include certain organic foods which, although oxidized 
in the Body and serving as liberators of energy, yet produce 
effects totully disproportionate to the energy they set free, 








208 THE HUMAN BODY. 


and for which effects they are taken. Inother words, their 
influence as stimuli in exciting certain tissues to liberate 
energy, or a3 inhibitory agents checking the activity of 
parts, is more marked than their direct action as force gen- 
erators. As examples, we may take condiments: mustard 
and pepper are not of much use as sources of energy, al- 
thongh they no doubt yield some; we take them for their 
stimulating effect on the mouth and other parts of the 
alimentary canal, by which they promote an increased flow 
of the digestive secretions or an increased appetite for 
food. Thein, again, the active principle of tea and coffee, is 
taken for its stimulating effect on the nervous system, rather 
than for the amount of energy which is yielded by its own 
oxidation, 

Conditions which a Food must Fulfill. (1) A food 
must contain the elements which it is to replace in the 
Body: but that aloneis not sufficient. ‘The elements leay- 
ing the Body being usually derived from the breaking down 
of complex substances in it, the food must contain them 
either in the form of such complex substances, or in forms 
which the Body can build up into them. Free nitrogen 
and hydrogen are no use as foods, since they are neither oxi- 
dizable under the conditions prevailing in the Body (and 
consequently cannot yield it energy), nor are they capable 
of construction by it into its tissues. (2) Food after it 
has been swallowed is still in a strict sense outside the 
Body; the alimentary canal is merely a tube running 
through it, and so long as food lies there it is not forming 
any part of the Body proper. Hence foods must be capa- 
ble of absorption from the alimentary canal; either directly, 
or after they have been changed by the processes of diges- 
tion. Carbon, for example, is no use as a food, not merely 
because the Body could not build it up into its own tissues, 
but because it cannot be absorbed from the alimentary 
canal. (3) Neither the substance itself nor any of the 
products of its transformation in the Body must be inju- 
tions to the structure or activity of any organ. If so it is 
a poison, not a food. 

Alimentary Principles, What in common language we 





ALIMENTARY PRINCIPLES, 209 


commonly call foods are, in nearly all cases, mixtures of 
several foodstuffs, with substances which are not foods at 
all. Bread, for example, contains water, salts, gluten (a 
proteid), some fats, much starch, and a little sugar; all true 
foodstuffs: but mixed with these is a quantity of cellulose 
(the chief chemical constituent of the walls which surround 
vegetable cells), and this is not a food since it is incapable 
of absorption from the alimentary canal, Chemical exami- 
nation of all the common articles of diet shows that the 
actual number of important foodstuffs is but small: they 
are repeated in various proportions in the different things 
we eat, mixed with small quantities of different flavoring 
substances, and so give us a pleasing variety in our meals; 
but the essential substances are much the same in the fare 
of the workman and in the ‘delicacies of the season.” 
‘These primary foodstuffs, which are found repeated in so 
many different foods, are known as “‘ alimentary principles;” 
and the physiological value of any article of diet depends 
on them far more than on the traces of flavoring matters 
which cause certain things to be especially sought after and 
so raise their market value. The alimentary principles 
may be conveniently classified into proteids, albuminoids, 
hydrocarbons, carbohydrates, and inorganic bodies. 

Proteid Alimentary Principles. Of the nitrogenous 
foodstuffs the most important are proteids: they form an 
essential part of all dicts, and are obtained both from 
animals and plants. ‘The most common and abundant are 
myosin and syntonin which exist in the lean of all meats; 
egg albumen; casein, found in milk and cheese; gluten and 
yegetable casein from various plants, 

Albuminoid Alimentary Principles. These also con- 
tain nitrogen, but cannot replace the proteids entirely as 
foods; though « man can get on with less proteids when he 
has some albuminoids in addition. The most important is 
gelatin, which is yielded by the white fibrous tissue of 
animals when cooked. On the whole the albuminoids are 
not foods of high value, and the calf's-foot jelly and such 
compounds, often given to invalids, have not nearly the 
uutritive value they are commonly supposed to possess, 











800 THE HUMAN BODY. 


Hydrocarbons (Futs and Oils). The most important 
are stearin, palmatin, margarin and olein, which exist in 
yarious proportions in animal fats and yegetable oila; the 
more fluid containing most olein. Butter consists chiefly of 
a fat known as butyrin. All are neutral compounds of gly- 
cerine and fatty acids and, speaking generally, any such sub- 
stance which is fusible at the temperature of the Body will 
serve as a food. The stearin of beef and mutton fats is 
not by itself fusible at the body temperature, but is mixed 
in those foods with so much olein as to be melted in the 
alimentary canal. Beeswax, on the other hand, is a fatty 
body which will not melt in the intestines and so passes on 
unabsorbed; although from its composition it would be 
useful as a food could it be digested. It is convenient to 
distinguish fats proper (the adipose tissue of animals 
consisting of fatty compounds inclosed in albuminous cell- 
walls) from oils, or fatty bodies which are not so surrounded, 

Carbohydrates, ‘These aro mainly of vegetable origin. 
‘The most important are starch, found in nearly all vege- 
table foods; dextrin; gums; grape sugar (into which starch 
is converted during digestion); and cane sugar. Sugar of 
milk and glycogen are alimentary principles of this group, 
derived from animals. All of them, like the fats, consist 
of carbon, hydrogen and oxygen; but the percentage of 
oxygen in them is much higher, there being one atom of 
oxygen for every two of hydrogen in their molecule. 

Inorganic Foods. Water; common salts; and the chlo- 
rides, phosphates, and sulphates of potassium, magnesium 
and calcium. More or Jess of these bodies, or the materials 
for their formation, exists in all ordinary articles of diet, 
«0 that we do not swallow them in a separate form. Phos- 
phates, for example, exist in nearly all animal and vegetable 
foods; while other foods, as casein, contain phosphorus 1 
combinations which in the Body yield it up to be oxidized 
to form phosphoric acid. ‘The same is true of sulphates, 
which are partially swallowed as such in yarious articles of 
diet, and are partly formed in the Body by the oxidation of 
the sulphur of various proteids. Calcium salts are abun- 
dant in bread, and are also found in many drinking waters. 





FLESH FOODS. 801 


Water and tablo salt form exceptions to the rule that in- 
organic bodies are eaten imperceptibly along with other 
things, since the Body loses more of each daily than is usu- 
ally eupplied in that way. It has, however, been main- 
tained that salt, as such, is an unnecessary luxury; and 
there seems some evidence that certain savage tribes live 
without more than they get in the meat and vegetables 
they eat. Such tribes are, however, said to suffer especially 
from intestinal parasites; and there is no doubt that to 
civilized man the absence of salt is a great deprivation. 

Mixed Foods. ‘These, as already pointed out, include 
nearly all common articles of diet; they contain more than 
one alimentary principle. Among them we find great 
differences; some being rich in proteids, others in starch, 
others in fats,and soon. The formation of ascientific die- 
tary depends on a knowledge of these characteristics. ‘The 
foods eaten by man are, however, 90 varied that we cannot 
do more than consider the most important. 

Plesh. This, whether derived from bird, beast, or fish, 
consists essentially of the same things—muscular fibres, 
tendons, fats, blood-veasels, and nerves. It contains several 
proteids and especially myosin; gelatin-yielding matters 
in the white fibrous tissue; stearin, palmatin, margarin, and 
olein among the fats; and a small amount of carbohydrates 
in the form of glycogen and grape sugar; also inosife, a 
kind of sugar found only in muscles. Flesh also contains 
much water and # considerable number of salines, the most 
important and abundant being potassium phosphate. Os- 
mazome is a crystalline nitrogenous body which gives much 
of its taste to flesh; and small quantities of various similar 
enbstances exist in different kinds of meat. There is also 
more or loss yollow elastic tissne in flesh; it is indigestible 
und useless as food. 

When meat is cooked its white fibrous tissue is turned 
into gelatin, and the whole mass becomes thus softer and 
more easily disintegrated bythe teeth. When boiled much 
of the proteid matters of the moat pass ont into the broth, 
and there in part coagulate and form the scum: this loss 
may be prevented in great part, if it is not intended to use 





et 
> 


eg er me ee St oe oo ee 
plato Ve etree thon foe = ee 
Rie tengo iw die we Ee oe ce the 
ein ne ree ome ehied a the 
Se Making sr comeing, sil tae wnlicd urte af 
mutertain apa Exeneed betes 
Ge sures ff wieh ie = few 
Vheos neta » Gege aman x egr bomen 
aed, 1 Chee 70M, annther pevtent, kanws se veel Also 
fate, wd & subatonce keen se loriviin (p. 14}, which is 
Miya wt nitig & omadersble yrsecity of phos 
sadael 
Mit, ‘This contains the proteid known ms cxecin; several 


nat 
rp 


7 

wyoarine, In the mille it ia disseminated in the form of 
wintle gotules witob, for the moxt part, float up to the top 
whan Ue mille Ww lat wtand and then form the cream, In 
(ia wach fat droplet i* earrounded by a pellicle of albumi- 
nin matter; by dhurning, those pellicles are broken up and 
tha fat deplete ran together to form the butter, Casein is 
jneoluble in water, aod in the roll it ia dimolved by the 
Whaling dalle prownt, Whon milk le kept ite sugar fer- 
tionte nnd givod Hine to lnatle weld, Which noutralizes the 
alkali and yprooipliatod the cavoin ax cerds. In choeso- 
Holling Hho camain le alintlarly prooipitated by the addition 
wl ai aot aud (Hie whey boli promed out) it constitutes 
tho Hani Walk oF Ue ehoow, 

Vewetabsin Pooda, Of (hoe wheat affords the best. In 
JOD parte It Mantwine 180 of protoids, S68 of starch, 46 of 
HOKU (A OAPRARYerate), 40 af grape sugar, 19 of fats, 
uit WO Wl velluhown, Che remainder being water and salts 
‘WW JINN Gof Ween Fk Waadwly gatetvn, which whem mois 
waved With Weak Reaann a foananiouts mass, and this it is to 
WWD WheAtO Rival Gees ite superiority, Whem the 
ARAN Ue Worth, weaind 6 a > i& aed pondanes a fermen 
WAV DY WANA, starr vale tangs. carter uscd gas 
W Yves Dei ees ongoumannd tn ter traces deg 





VEGETABLE FOODS. 308 


and expanded during baking, forms cavities in it and causes 
it to “‘rise” and make “light bread,” which is not only 
more pleasant to eat but more digestible than heavy. Other 
cereals may contain « larger percentage of starch but none 
have so much glaten as wheat; when bread is made from 
them the cubon dioxide gas escupes 80 readily from the leas 
tenacious dough that it does not expand the mass properly. 
Corn contains in 1000 parts, 79 of proteids, 637 of starch, and 
from 50 to 87 of fats; much more than any other kind of 
grain. Rice is poor in proteids (56 parts in 1000) but very 
rich in starch (823 partsin 1000). Peas and deans are rich 
in proteids (from 220 to 260 parts in 1000), and contain about 
half their weight of starch. Potatoes area poor food. They 
contain a great deal of water and cellulose, and only about 
13 parts of proteids and 154 of starch in 1000, Other fresh 
vegetables, as carrots, turnips and cabbages, are valuable 
mainly for the salts they contain; their weight is mainly due 
to water, and they contain but little starch, proteids, 
or fats. Fruits, like most fresh vegetables, are mainly valu- 
able for their saline constituents, the other foodstuffs in them 
being only present in small proportion. Some form of 
fresh vegetables is, however, a necessary article of diet; as 
shown by the scurvy which used to prevail among sailors 
before fresh vegetables or lime-juice were supplied to them. 

The Cooking of Vegetables. Thisis of more importance 
even than the cooking of flesh, since in most the main ali- 
mentary principle is starch, and raw starch is difficult of 
digestion, In plants starch is nearly always stored up in 
the form of solid granules, which consist of alternating 
layers of starch cellulose and starch granulose. The diges- 
tive flaids turn the starch into grape sugar which is soluble 
and can bo absorbed from the alimentary canal, while starch 
itself cannot. Now these fluids act very slowly and imper- 
fectly on raw starch, and then only on the granulose; but 
when boiled, the starch granules swell up, and are more 
readily converted into grape sugar; and the starch cellulose 
isso altered that it too undergoes thatchange. When starch 
is roasted it is turned into a substance known as soluble 
starch which is readily dissolved in the alimentary canal: 














. 





B0L THE HUMAN BODY. 


There is therefore a scientific foundation for the common 
belief that the crust of a loaf is more digestible than the 
crumb, and toast than ordinary bread. 

Alcohol, ‘There are perhaps no common articles of 
diet concerning which more contradictory statements have 
been made than alcoholic drinks. This depends upon their 
peculiar position: according to quantity or circumstances 
aleohol may be & poison or a food; and as a food it may be 
regarded cither as a force regulator or a foree generator. 
There is no doubt that alcohol in certain doses may be prop- 
perly called a food. If not more than two ounces (which 
would be contained in about four ounces of whiskey or two 
quarts of lager beer) are taken in the twenty-four hours, it 
is completely oxidized in the Body and excreted as water 
and carbon dioxide. In this oxidation energy is of course 
liberated and can be utilized. Commonly, however, aleo- 
hol is not taken for this purpose but, as a force regulator, 
for its influence on the nervous system or digestive organs, 
and it is in this capacity that it becomes dangerous. For 
not only may it be taken in quantities so great that it is 
not all oxidized in the Body but is passed through it us uleo- 
hol, or even that it acta as a narcotic poison instead of a 
stimulant, but when taken in what is called moderation 
there cun be no doubt that the constant “whipping up” of 
the flagging organs, if continued, must be dangerous to 
their integrity. Hence the daily use of alcohol merely m 
auch quantities as to produce slight exhilaration or to facili- 
tate work is by no means safe; though in disease when the 
system wants rousing to make some special effort, the phy- 
sician cannot dispense with it or some other similarly act- 
img substance. In fact, asa force generator alcohol may be 
advantageously replaced by other foods in nearly all cases; 
and there is no evidence that it helps in the constraction 
of the working tissnes, though its excessive use often leads 
to an abnormal accumulation of fat. Its proper use 18 as 
a “whip,” and one has no more right to use it to the 
healthy Body than the lash to overdrive a willing horse. 
The physician is the proper person to determine whether it 


fs wanted under any given circumstances. 


ALCOHOL. 305 


If alcohol is to be used as a daily article of diet it should 
be borne in mind that when concentrated it coagulates the 
proteids of the cells of the stomach with which it comes in 
contact, in the same sort of way, though of course to a 
much leas degree, as it shrivels and dries up an animal pre- 
served in it. Dilute alcoholic drinks, such as claret and beer, 
are therefore far less baneful than whiskey or brandy, and 
these are worst of all in the almost undiluted form of most. 
* mixed drinks.” Por the same reason alcohol is far more 
injurious on an empty stomach than after a meal. When 
the stomach is fall it is diluted, is more slowly absorbed, 
and, moreover, is largely used up in coagulating the proteids 
of the food instead of those of the lining membrane of the 
stomach. ‘The old “three bottle” men who drank their 
port-wine after a heavy dinner, got off far more safely than 
the modern tippler who is taking ‘‘nips” all day long, 
although the latter may imbibe a smaller quantity of aleo- 
hol in the twenty-four hours. By far the best way, how- 
ever, is to avoid alcohol altogether in health. If the facts 
lead us to conclude, against the extremists, that it 1s toa 
certain extent a food, it is nevertheless a dangerous one; 
even in what we may call ‘physiological " quantities, or 
such amounts as can be totally oxidized in the Body. 

Tho Advantage of a Mixed Diet. The necessary quan- 
tity of daily food depends upon that of the material daily 
lost from the Body, and this varies both in kind and 
amount with the energy expended and the organs most 
used. In children a certain excess beyond this 1s required 
to furnish materials for growth. ° Althongh it is impossible 
to Tay down with perfect aceuracy how much daily food any 
individnal requires, still the average quantity may be de- 
rived from the table of daily losses given on page 278, 
which shows that a healthy man nocds daily in assimilable 
forms about 274 grams (4220 grains) of carbon and 19 
grams (292 grains) of nitrogen. The daily Joss of hydrogen 
which is very great (352 grame or 5428 grains), 13 nearly all 
that contained in water which has been drunk and, so to 
speak, merely filtered through the Body, after having 
assisted in the solution and transference through it of other 








306 THE HUMAN BODY 


substances. About 300 grams (4620 grains) of water 
(containing 33.3 grams (513 grains) of hydrogen are, how- 
ever, formed in the Body by oxidation, and the hydrogen for 
this purpose must be supplied in the form of some oxidiza- 
ble foodstufl, whether proteid, fat, or carbohydrate. The 
oxygen wanted is mainly received from the air through the 
lungs, but some is taken in the food. 

Since proteid foods contain carbon, nitrogen and hydro- 
gen, life may be kept up on them alone, with the necessary 
salts, water and oxygen; but such a form of feeding would 
be anything but economical, Ordinary proteids contain in 
100 parts (p. 10) about 5% of carbon and 15 of nitrogen, so 
a man fed on them alone would get about 34 parte of carbon 
for every 1 of nitrogen. His daily Josses are not in this 
ratio, but about that of 274 grams (4220 grains) of carbon 
to 20 grams (308 grains) of nitrogen, or as 13.7 to 1; and 
+o to get enough carbon from proteids far more than the 
necessary amount of nitrogen must be taken. Of dry 
proteids 627 grams (8116 grains) would yield the necessary 
carbon, but would contain 79 grams (1217 grains) of 
nitrogen; or four times more than is necessary to cover the 
daily losses of that element from the Body. Fed on a 
purely proteid dict a man would, therefore, have to digest a 
vast quantity to get enough carbon, and in eating and 
absorbing it, as well as in getting rid of the extra nitrogen 
which is useless to him, a great deal of unnecessary labor 
would be thrown upon the various organs of his Body. 
Similarly, if « man were to live on bread alone he would 
burden his organs with much useless work. For bread 
contains but little nitrogen in proportion to its carbon, and 
80, to get enough of the former, far more carbon than was 
utilized would have to be caten, digested, and eliminated 
daily. 

Accordingly, wo find that mankind in genoral employ 1 
mixed diet when they can get it, using richly proteid sub- 
stances to supply the nitrogen needed, but deriving the 
carbon mainly from non-nitrogenous foods of the fatty or 
carbohydrate groups, and so avoiding excess of either. For 
instance, loan beef contains about } of its weight of dry 








‘ ADVANTAGE OF A MIXED DIET. 807 


tee. 
proteid, which contains 15 per cent of nitrogen. Conse. 
quently the 133 grams (2048 grain) 9f proteid which 
would be found in 532 grams (1 Ib. 3 oz.) of lean meat 
would supply all the nitrogen needed to compensate for a 
day's losses. But the proteid contains 52 per cent of 
carbon, so the amount of it in the above weight of fatless 
meat would be 69 grams (1062 grains) of carbon, leaving 
205 grams (3157 grains) to be got either from fats or car- 
bohydrates. The necessary amount would be contained 
in about 256 grams (3942 grains) of ordinary fats or 460 
grams (7084 grains) of starch; hence either of these, with 
the above quantity of lean meat, would form a far better 
dict, both for the purse and the system, than the meat alone. 
As already pointed out, nearly all common foods contain 
several foodstuffs. Ordinary butcher’s meat, for example, 
contains nearly half its weight of fat; and bread, besides 
proteids, contains starch, fats, and sugar. In none of them, 
however, are the foodstuffs mixed in the physiologically 
best proportions, and the practice of employing several of 
them at each meal or different ones at different meals 
during the day, is thus not only agreeable to the palate but 
in a high degree advantageous to the Body. The strict 
vegetarians who do not employ even such substances as 
eggs, cheese, and milk, but confine themselves to a purely 
vegetable diet (such as is always poor in proteids), daily take 
far more carbon than they require, and are to be congratu- 
lated on their excellent digestions which are able to stand 
the strain. Those who use eggs, cheese, ote., can of course 
get on very well, simce such substances are extremely rich 
in proteids, and supply the nitrogen needed without the 
necessity of swallowing the vast bulk of food which must 
be eaten in order to get it from plants directly. 








CHAPTER XXI 


THE ALIMENTARY CANAL AND ITS APPEN- 
DAGES. 


General Arrangement, The alimentary canal is essen- 
tially an involuted portion of the skin, specially set apart 
for absorption, and forming a tube which rans through 
the Body (Fig. 2); it communicates with the exterior at 
three points (the nose, the mouth, and the anal aperture). 
at which this modified skin, or mucous membrane, 18 con- 
tinuons with the general outer integument. Supporting 
the lining absorptive membrane are other layers which 
strengthen the tube, and are also in part muscular and, 
by their contractions, serve to pass materials along it from 
one end to the other. In the walls of the canal are 
numerous blood and lymphatic vessels which carry off the 
matters absorbed from its cavity; and there also exist in 
connection with it numerous glands, whose function it is ta 
pour into it various sceretions which exert a solvent influ- 
ence on such foodstuffs as would otherwise escape absorp- 
tion. Some of these glands are minute and imbedded jn 
the walls of the alimentary tube itself, but others (such 
as the salivary glands) are larger and lie away from the 
main channel, into which their products are carried by ducts 
of various lengths. 

The alimentary tube is not uniform but presents several 
dilatations on its course; nor isit straight, since, being much 
longer than the Body, it is packed away by being coiled up 
in the abdominal cavity. 

Subdivisions of the Alimentary Canal. The mouth 
opening leads into a chamber containing the teeth and 
tongue, the mouth chamber or buccal cavity. This is suc- 





MOUTH CAVITY. 


308 


ceeded by the pharynx or throat cavity, which narrows at 
the top of the neck into the gullet or esophagus; this rans 
down through the thorax and, pussing through the dia- 
phragm, dilates in the upper part of the abdominal cavity 


into the stomach. Beyond 
the stomach the channel again 
narrows to form a long and 
greatly coiled tube, the smal 
tniestine, which terminates by 
opening into the large intes- 
tine, much shorter although 
wider than the small, and ter- 
minating by an opening on 
the exterior. 

The Mouth Cavity (Fig. 
89) is bounded in front and 
on the sides by the lips and 
checks, below by the tongue, 
&, and above by the palate; 
which latter consists of an an- 
terior part, 7, supported by 
boue and called the hard pal- 
ate, and a posterior, f, con- 
taining no bone, and called 
the soft palate. The two can 

ily be distinguished by 
applying the tipof the tongue 
to the roof of the mouth and 
dmwing it backwards. 
hard palate forms the parti- 
tion between the mouth and 
nose. The soft palate arches 
down over the back of the 
mouth, banging like  onr- 


Tho Tian 


10, F9.—The mouth, nose atid 
sypie wit the cousnaogmsens ‘the 
eulled and Larynx, as 


le to the Ja ‘of theme, 
vertebral 


. the 
‘ante base of the eeull 
the tere sar ‘of the crani 
‘tabinate bones of the clit: 


OeFidl oP tne lett moetel chamber 


tain between it and the pharynx, as can be seen by holding 
the month open in front of » looking-glass. From the 
middle of its free border a coniesl process, the nvada, hangs 


down. 


The Teeth. Immediately within the cheeks and lips are 











310 THE HUMAN BODY. 


two semicircles, formed by the borders of the upper and 
lower jaw-bones, which are covered by the gums, except at 
intervals along their edges where they contain sockets in 
which the tecth are implanted. During life two sets of 
teeth are developed; the first or milk set appears soon after 
birth and is shed during childhood, when the second 
or permanent set appears. 

The teeth differ in minor points from one another, but 
in all three parts are distinguishable; one, seen in the 
mouth and called the crown of the tooth; a second, im- 
bedded in the jaw-bone and called the root or fang; and 
between the two, embraced by the edge of the gum, is a 
narrowed portion, the neck or cerviz, From differences in 
their forms and uses the teeth are divided into incisors, 
canines, bicuspids, and molars, arranged in a definite order 
in each jaw. Beginning at the middle line we meet in 
each half of each jaw with, successively, two incisors, one 
canine, and two molars in the milk-set; making twenty 
altogether in the two jaws. Tho teeth of the permanent 
set are thirty-two in number, eight in each half of each 
jaw, viz.—beginning at the middle line—two incisors, one 
canine, two bicuspids, and three molars. The bicuspids, or 
premolars, of the permanent set replace the milk molars, 
while the permanent molars are new teeth added on as the 
jaw grows, and not substituting any of the milk teeth. 
The hindmost permanent molars are often called the wis- 
dom teeth. 

Characters of Individual Teeth. The incisors (Fig. 
90) are adapted for cutting the food. Their crowns are 
chisel-shaped and have sharp horizontal cutting edges, 
which become worn away by use eo that they are beveled 
off behind in the upper row, and in the opposite direction 
in the lower. Each has a single long fang. The canines 
(Fig. 91) are somewhat larger than the incisors. Their 
crowns are thick and somewhat conical, having a central 
point or evsp on the cutting edge. In dogs, cats, and 
other carnivora the canines are very large and adapted for 
seizing and holding prey. The dicuspids or premolars 
(Fig. 92) are rather shorter than the canines and their 





=: 


THE TEETH. 811 


crowns are somewhat cuboidal. Each has two cusps, an 
outer towards the cheek, and an inner on the side turned 
towards the interior of the mouth. The fang is compressed 
laterally, and has usually a groove partially subdividing it 


incisor tooth. 
‘canine oF eye tooth. 
bicuspid 190th ween from Ite outer wide; the inner cusp is, accord: 


into two. At its tip the soparation is often complete. 
The molar teeth or grinders (Pig. 93) have large crowns 
with broad surfaces, on which are four or five projecting 
tubercles, which roughen them and make them better adapt- 
ed to crush the food. Buch has usually several fangs. The 
milk teeth ouly differ in subsidiary points from those of 
the same names in the permanent set. 

The Structure of a Tooth. If a tooth be broken open 
a cavity extending through both crown and fang will be 
found in it. This is filled during life with a soft vascular 
pulp, and hence is known as the “pulp cavity” (c, Fig. 
94). The hard parts of the tooth disposed around the pulp 
cavity consist of three different tissues. Of these one im- 
mediately surrounds the cavity and makes up most of the 
bulk of the tooth; it is dentine (2, Fig. 94); covering the 
dentine on the crown is the enamel (1, Fig. 94) and, on the 
fang, the cement (3, Fig. 94). 

The pulp cavity opens below by a narrow aperture at the 
tip of the fang, or at the tip of each if the tooth has more 
than one. The pulp consists mainly of connective tissue, 
but its surface next the dentine is covered by a layer of 








812 THE HUMAN BODY. 


columnar cells, Through the opening on the fang blood- 
vessels and nerves enter the pulp. 
‘The dentine yields on chemical analysis the same mate- 





Fro, 4.—Section through m premolar tooth of the eat stilt imbedded An tts 
focket, 1, enamel; 2 dentine; 4, cement; 4, the gum, §,the bone of ihe lower 
Jaw ; 6, the pulp cavity. 

rials us bone but is comewhat harder, earthy matters con- 
stituting 72 per cent of it as against 66 per cent in bone, 
Under the microscope it is recognized by the fine dendinal 





THE TONGUE. 815 


tubules which, radiating from the pulp eavity, perforate it 
throughout, finally ending in minute branches which open 
into irregular cavities, the inéerglobular spaces, which lie 
just beneath the enamel or cement, At their widest ends, 
close to the pulp cavity, the dentinal tubules are only 
about 0.005 millimeter (p¢55 of an inch) in diameter. 
‘The cement is much like bone in structure and composition, 
possessing lacunw and canaliculi but rarely any Haversian 
canals, It is thickest at the tip of the fang and thins 
away towards the cervix. namel is the hardest tissue in 
the Body, yielding on analysis only from two per cent to 
three per cent of orgunic matter, the rest being mainly 
calcium phosphate and carbonate. Its histological ele- 
ments are minate hexagonal prisms, closely packed, and set 
on vertically to the surface of the subjacent dentine. It is 
thickest over the free end of the crown, until worn away by 
use. Covering the enamel in unworn teeth is # thin struc~ 
tureless horny layer, the enamel cuticle. 
The Tongue (Fig. 95) is a muscular organ covered with 
4 mucous membrane, extremely mobile, and endowed not 
only with a delicate tactile sensibility but with the ter- 
minal organs of the special sense of taste; it is attached 
by its root to the hyoid bone. Its upper surface is covered 
small eminences or papillae, much like those more 
developed on the tongue of a cat, where they are 
elt. On the human tongue there are three kinds 
of papille, the eircumvallate, the fungiform, and the fili- 
form. The cireumvallate papillw, 1 and 2, the largest 
and least numerous, are from seven to twelve in number 
and lie near the root of the tongue arranged in the form of 
a V with its open angle turned forwards, ach is an ele- 
vation of the mucous membrane, covered by epithelium, 
and surrounded by a trench. On the sides of the papilla, 
imbedded in the epithelium, are small oval bodies (Fig. 155) 
richly supplied with nerves and supposed to be concerned 
in the sense of taste, and hence called the taste buds 
(Chap. XXXIV.) The fungiform papilla, 3, wre rounded 
elevations attached by somewhat narrower stalks, and found 
all over the middle and fore part of the upper surface of 








314 THE HUMAN BODY. 


the tongue. They are easily recognized on the living 
tongue by their bright red color. The filiform papilla, 
most numerous and smallest, are scattered all over the dor- 





Fro. 2.—The apper surface of the tongue. t, 2.¢ 
eiform papillae; 4, Oiform papilla; 6, mucous gla 
whottie, 





ralinte papttine; fn 
+ 7, tonsils; & part of epl 


sum of the tongue except near its base. Bach is a conical 
eminence covered by a thick horny layer of epithelium. 
Tt is these papillae which are so highly developed on the 


tongues of Carnivora, and serve them to scrape bones clean 





THE SALIVARY GLANDS. B15 


of even such tough structures as ligaments. Tamed tigers 
have been known to draw blood by licking the hand of their 
master. 

Note, In health the surface of the tongue is moist, 
covered by little “fur,” and in childhood of a red color. 
In adult life the natural color of the tongue is less red, ex- 
cept around the edges and tip; a bright red glistening 
tongue being, then, usually a symptom of disease. When 
the digestive organs are deranged the tongue is commonly 
covered with a thick yellowish coat, composed of a little 
mucus, a few cells of epithelium shed from the surface, and 
numerous microscopic organisms known as bacteria; and 
there is frequently a ‘bad taste” in the mouth, The 
whole alimentary mucous membrane is in close physio- 
logical relationship; and anything disordering the sto- 
mach is likely to produce a *‘furred tongue.” 

The Salivary Glands. The saliva, which is poured into 
the mouth and which, mixed with the secretion of minute 
glands imbedded in its lining membrane, moistens it, is 
secreted by three pairs of glands, the parotid, the submaxil- 
Jary and the sublingual, The parotid glands lie in front 
of the ear behind the ramus of the lower jaw; cach sends 
its secretion into the mouth by a tube known a3 Stenon’s 
duct, which crosses the check and opens opposite the second 
upper molar tooth. In the disease known as mumps the 
parotid glands are inflamed and enlarged. The submaxillary 
glands lie between the halves of the lower jaw-bone, near 
its angles, and their ducts open beneath the tongue near the 
middle line. The sublingual glands lie beneath the floor 
of the mouth, covered by its mucous membrane, between 

+ the back part of the tongue and the lower jaw-bone. Each 
has many ducts (8 to 20), some of which join the submaxil- 
lary duct, while the reat open separately in the floor of the 
mouth. 

The Fauces is the name given to the aperture which can 
be seen at the back of the mouth (Fig. 89), leading from it 
into the pharynx below the soft palate. It is bounded 
above by the soft palate and nyula, below by the root of the 
tongue, and on the sides by muscular elevations, covered by 


ia 





B16 THE HUMAN BODY. 


mucous membrane, which reach from the soft palate to the 
tongue. These clevations are the pillars of the fances. 
Each bifurcates below, and in the hollow between its divi- 
sions lies a tonsil (7, Fig 95), asoft rounded body about the 
size of an almond, and containing numerous minute glands 
which form mucus. 

Note. The tonsils not unfrequently become enlarged 
during « cold or sore throat, and then pressing on the 
Eustachian tube (Chap. XXXIII.), which leads from the 
pharynx to the middle ear, keep it closed and produce tem- 
porary deafness. Sometimes the enlargement is permanent 
and causes much annoyance. The tonsils can, however, be 
readily removed without danger, and this is the treatment 
usually adopted in such cases. 

The Pharynx or Throat Cavity (Fig. 89). ‘This por- 
tion of the alimentary canal may be desoribed as a conical 
bag with its broud end turned upwards towards the base of 
the skull, and its narrow end downwards and passing inte 
the gullet. Its front is imperfect, presenting apertures 
which lead into the nose, the mouth, and (through the 
larynx and windpipe) into the lungs. Exeept when fool 
is being swallowed the soft pulate hangs down between tho 
mouth and pharynx; during deglutition it is raised into a 
horizontal position and separates an upper or respiratory 
portion of the pharynx from the rest. ‘Through this 
upper part, therefore, air alono passes, entering it from the 
posterior ends of the two nostril chambers; while through th 
lower portion both food and air pass, one on its way to the 
gullet, 0, Fig. 89, the other through the larynx, d, to the 
windpipe, ¢; when a morsel of food “ gocs the wrong 
way” it takes the latter course, Opening into the upper 
portion of the pharynx on each side is an Eustachian tube, 
g: so that the apertures leading out of it are seven in num- 
bor; the two posterior nares, the two Eustachian tubes, the 
fuuces, the opening of the larynx, and that of the gul- 
let. At the f the tongue, over the opening of the 
larynx, is a plate of cartilage, the epiglottis, e, which can be 
seen if the mouth is widely opened and the back of the 
tongue pressed down by some such thing as the handle of 





THE STOMACH 


aspoon. During swallowing the epiglottis is pressed down 
like a lid over the air-tube and helps to keep food or saliva 
from entering it. In structure the pharynx consists essen- 
tially of a bag of connective tissue lined by mucous mem- 
brane, and having muscles in its walls which, by their con- 
tractions, drive the food on. 

Tho CEsophagus or Gullet is a tube commencing at the 
lower termination of the pharynx and which, passing on 
through the neck and chest, ends in the stomach below the 
diaphragm. In the neck it lies close behind the windpipe. 
Tt consists of three coats—a mucous membrane within; next, 
a submucons coat of areolar connective tissue; and, outside, 
@ muscular coat made up of two layers, an inner with trans- 
verse and an outer with longitudinally arranged fibres. In 
and beneath its mucous membrane are numerous small 
glands whose ducts open into the tube. 

The Stomach (Fig. 96) is a somewhat conical bag placed 
transversely in the upper part of the abdominal cavity. Its 
larger end is turned to 
the left and lies close 
beneath the diaphragm; 
opening into its upper 
border, through the ear- 
diac orifice at a, is the 
gullet, d. The narrower 
right end is continuous 
atc with the small intes- 
tine; the communication 
between the two is the 
pyloric orifice. The py- (0s Gully or ponent oF Ose etna wee 
lorie end of the stomach Bim bite mandi 6 oe Pes te 
lies lower in the abdomen {ame ts? iP tne icone carratane 
than the cardiac, and is 
separated from the diaphragm by the liver (see Fig. 1) 
‘The concave border between the two orifices is known as 
the small curvature, and the convex as the great curvature, 
of the stomuch. From the latter hangs down a fold of 
peritoneum (ne, Fig. 1) known as the great omentum. Tt 
is spread over the rest of the abdominal contents like an 





a 





‘THE HUMAN BODY, 


apron, After middle life much fat frequently accumulates 
in the omentum, so that it is largely responsible for the 
* fair round belly with good capon lin’d.” The protrusion 
} to the left side of the cardiac orifice, Fig. 96, is the fun- 
dus or great cul de sac. The size of the stomach varies 
greatly with the amount of food in it; just after a mode- 
rate meal it is about ten inches long, by five wide at its 
broadest part. 

Structure of the Stomach. This organ has four coats, 
known successively from without in as the serous, the mus- 
cular, the submucous, and the mucous, The serous coat is 
formed by a reflexion of the peritoneum, a double fold of 
which slings the stomach; after separating to envelop it the 
two layers again unite and, hanging down beyond it, form 
thegreat omentum. The muscular coat (Fig.54*) consists of 
unstriped musenJar tissue arranged in three layers: an outer, 
longitudinal, most developed about the curvatures; a cireu- 
lar, evenly spread over the whole organ, except around the 
pyloric orifice where it forms a thick ring; and an inner, 
oblique and very incomplete, radiating from the cardiac 
orifice. The sudmucous coat is made up of lax areolar 
tissue and binds loosely the mucous coat to the muscular, 
‘The mucous coat is a moist pink membrane which is 
inelastic, and large enough to line the stomach evenly when 
it is fully distended. Accordingly, when the organ is 
empty and shrunk, this coat is thrown into folds. During 
digestion the arteries supplying the stomach become dilated 
and, its capillaries being gorged, its mucous membrane is 
then much redder than when the organ is empty. 

The blood-vessels of the stomach run to it between the 
folds of peritoneum which sling it. After giving off a 
few branches to the outer layers, most of the arteries 
break up into small branches in the submucous coat, from 
which twigs proceed to supply the close capillary network 
of the mucous membrane. The pnreumogastrie nerves 
(p. 171) end in the stomach, and it also gets branches from 
the sympathetic system. 

Histology of the Gastric Mucous Mambrane. Exami- 
nution of the inner surface of the stomach with a hand 


= *P. 1a, 





ill 


STRUCTURE OF STOMACH. 319 


Tens shows it to be covered with minute shallow pits. Into 
these open the mouths of minute tubes, the gastric glands, 
which are closely packed side by side in the mucous 
membrane; there being between them only a small amount 
of connective tissue, a close network of lymph-channels, 
and capillary blood-vessels. The whole surface of the 
mucous membrane is lined by a single layer of columnar 
epithelium cells (Fig. 97). These dip down and line the 
tubniar glands, being in some (especially those about the 
pyloric end of the stomach) but little modified in appear- 
ance (c, Fig. 97). In others the epithelial cells become 
shorter and cuboidal, and 
have beneath them (a and d, 
Fig.97) a second incomplete 
layer of much larger oval 
cells, d. The glands of this 
second kind are the most 
numerous, and have been 
called peptic glands from 
the idea that they alone 
formed pepsin, the essential 
digestive ingredient of the 
gastric juice; this is how- 
ever by no means certain. 
The peptic glands frequently branch at their deeper 
ends, 

The Pylorus. If the stomach be opened it is seen that 
the mucous membrane projects ina fold around the pyloric 
orifice and narrows it. This is due to a thick ring of the 
circular muscular layer there developed, and forming a 
sphincter muscle around the orifice, which in life, by its 
contraction, keeps the passage to the small intestines closed 
except when portions of food are to be passed on from 
the stomach to succeeding divisions of the alimentary 
canal. 

Note. The cardiac end of the stomach lying immediately 
beneath the diaphragm, which has the heart on its upper 
side, o¥er-distension of the stomach, due to indigestion or 
flatulence, may impede the action of the thoracic organs, and 














B26 THE HUMAN BODY. 


cause feelings of oppression in the chest, or palpitation of 
the heart. ‘ 

‘The Small Intestine, commencing at the pylorus, ends, 
after many windings, in the large. It is about six meters 
{twenty feet) long, and about five centimeters (two inches) 
wide at its gastric end, narrowing to about two thirds of 
that width at its lower portion. Externally there are no 
lines of subdivision on the small intestine, but anatomists 
arbitrarily describe it as consisting of three parts; the first 
twelve inches being the duodenum, the succeeding two fifths 
of the remainder the jejunum, and the rest the tleum, 

Like the stomach, the small intestine possesses four coats: 
a serous, a muscular, a submucons, and a mucous. The 
serous coat is formed by a duplicature of the peritoneum, 
but presenta nothing answering to the great omentum; this 
double fold, slinging the intestine as the small omentum 
slings the stomach, is called the mesentery. The muscular 
coal is composed of plain muscular tissue arranged in two 
strata, an outer longitudinal, and an inner transverse or 
circular. The submucous coat is like that of the stomach; 
consisting of loose areolar tissue, binding together the mu- 
cous and muscular coats, and forming a bed in which the 
blood and lymphatic vessels (which reach the intestine in 
the fold of the mesentery) break up into minute branches 
before entering the mucous membrane. 

‘The Mucous Coat of the Small Intestine, Thisis pink, 
soft, and extremely vascular, It does not present tempo- 
rary or effaceable folds like those of the stomach, but is, 
throughont a great portion of its length, raised up into per- 
manent transverse folds in the form of crescentic ridges. 
each of which runs transversely for a greater or less way 
round the tube (Fig. 98). These folds are the valeule 
conniventes, They are first found about two inches from 
the pylorus, and are most thickly set and largest in the 
upper half of the jejunum, in the lower half of which they 
become gradually less conspicuous; and they finally disappear 
altogether about the middle of the ileum. ‘The folds 
serve greatly to increase the surface of the mucous mem- 
brane both for absorption and secretion, and they also de- 








SMALL INTESTINE. 821 


lay the food somewhat in its passage, since it must collect in 
the hollows between them, and so be longer exposed to the 
action of the digestive liquids. Examined closely with the 
eye or, better, with a hand lens, the mucous membrane of 
the small intestine is seen to be not smooth but shaggy, be- 
ing covered everywhere (both over the valyulw conniventes 
and between them) with closely packed minute processes, 
standing up somewhat like the “pile” on velvet, and known 
as the villi. Each villus is from 0.5 to 0.7 millimeters 
(2p to zy inch) long; some are conical and rounded, but 
the majority are compressed at the base in one diameter 
(Fig. 99). In structure a villus is somewhat complex. 
Covering it isa single layer of columnar epithelial cells, be- 
neath which the villus may be regarded as made up of a 


Fp, {8A portion of the small intestine opened to show the taloular conni- 
ventes. 


framework of connective tissue supporting the more essen- 
tial constituents. Near the surface is an incomplete layer 
of plain muscular tissue, continuous below with a muscular 
layer found on the deep side of the mucous membrane. In 
the centre is an offshoot of the lymphatic system; some- 
times in the form of a single vessel with a closed dilated 
ond, and sometimes as a network formed by two main ves- 
sels with cross-branches. During digestion these lym- 
phaties aro filled with a milky white liquid absorbed from 
the intestines and they are accordingly called the Jacteals, 
They communicate with larger branches in the submucous 
coat which end in trunks that pass out in the mesentery to 
join the main lymphatic system, Finally, in each villus, 











» 
332 THE HUMAN BODY. 

outside the lncteals and kencath the muscular layer, is a close. 
network of blood-veasela, 

Opening on the surface of the small intestine, between 
the bases of the villi, are small glands, the crypts of Lieber- 
kithn. Each is a simple unbranched tube lined by a layer 
of columnar cells similar to that which covers the villi and 
the surface of the mucous membrane between them, In 





0.—Villl of the small 
the laces 


id 4, 
fol tn the righthand fgut 
Lin jection. 





‘The eplth um covering the villl, 
comin 


structure they greatly resemble the mucous glands of the 
stomach (¢, Fig. 97). In the duodenum are found other 
minute glands, the glands of Brunner. They lie in the 
submucous coat and send their ducts through the mucots 
membrane to open on its inner side. 

‘The Large Intestine, forming the final portion of the 
alimentary canal, is about 1.5 meters (5 feet) long, and 
varies in diameter from about 6 to 4 centimeters (24 to 14 
inches), Anatomists describe it as consisting of the cacum 
with the vermiform appendiz, the colon, and the rectum. 
The small intestine does not open into the commencement 
of the large but into its side, some distance from its closed 





ail 


THE LIVER. 


upper end, and the cecum is that part of the large intes- 
tine which extends beyond the communication. From it 
projects the vermiform appendiz, a narrow tube not thicker 
than a cedar pencil, and about 10 centimeters (4 inches) 
long. ‘The colon commences on the right side of the 
abdominal cayity where the small intestine communicates 
with the large, rans up for some way on that side (ascend- 
ing colon), then crosses the middle line (transverse colon) 
below the stomach, and turns down (descending colon) 
on the left side and there makes an S-shaped bend known 
as the sigmoid flexure; from this the rectum, the termi- 
nal straight portion of the intestine, proceeds to the anal 
opening, by which the slimentary canal communicates 
with the exterior. In structure the large intestine presents 
the same coats as the small. The external stratum of the 
muscular coat is nob, however, developed uniformly around 
it, except on the rectum, but oceura in three bands separated 
by intervals in which it is wanting. These bands being 
shorter than the reat of the tube cause it to be puckered, or 
sacculated, between them. ‘The mucous coat possesses no 
villi or valrule conniventes, but is usually thrown into 
offaceable folds, like those of the stomach but smaller. It 
contains numerous closely set glands much like the erypts 
of Lieberkihn of the small intestine. 

Tho Moo-Colic Valve. Where tho small intestine joins 
the large there is a valve, formed by two flaps of the mucous 
membrane sloping down into the ‘colon, and so disposed as 
to allow matters to pass readily from the ileum into the 
large intestine but not the other way. 

‘The Liver. Besides tho secretions formed by the glands 
imbedded in its walls, the small intestine receives those of 
two other large glands, the liver and panereas, which lie 
in the abdominal cavity. The ducts of both open by a 
eommon aperture into the duodenum about 10 centimeters 
(4 inches) from the pylorus. 

The fiver is tho largest gland in the Body, woighing from 
1400 to 1700 grams (50 to 64 ounces). It is situated in the 
upper part of the abdominal cavity (/e, i’, Pig. 1), rather 
more on the right than on tho left side and immodiately below 





B24 THE HUMAN BODY, 


the diaphragm, into the concavity of which its upper sur- 
face fits; it reaches across the middle line above the pyloric 
end of the stomach. It is of dark reddish-brown color, 
and of a soft friable texture. A deep fissure incompletely 
divides the organ intoright and left lobes, of which the right 
is much the larger; on its under surface (Fig. 100) shallower 
grooves mark off several minor lobes. Its upper surface 
is smooth and convex. The vessels carrying blood to the 
liver are the portal vein, Vp, and the hepatic artery; both 
enter it ata fissure (the portal fissure) on its under side, and 
there also a duct passes out from each half of the organ. 


ve’ Vp op Vb Ly 

sii ree ea nfrire Dok, comanen lea? De 
pyle wood Dh, bepatic ducts Vf, gall-blad: 
‘The ducts unite to form the hepatic duct, Dh, which moots wt 
an acute angle, the cystic duct, De, proceeding from the 
gall-bladder, Vf, a pear-shaped sac in which the bile, or gall, 
formed by the liver, accumulates when food ia not being di- 
gested in th testine. The common bile-duet, Deh, formed 
by the uni the hepatic and cystic ducts, opens into 
the duodenum. The blood which entors the liver by the 
portal vein and hepatic artery passes out by the hepatic 
veins, Vh, which leave the posterior border of the organ 





HISTOLOGY OF LIVER, B25 


¢lose to the vertebral column, and there open into the infe- 
rior vena cava, Vr, just before it passes up through the 
diaphragm. 

The Structure of the Liver. On closely examining 
the surface of the liver, it will be seen to be marked out 
into small angular areas from one to two millimeters (gy 
to yy inch) in diameter. These are the outer sides of the 
superficial layer of a vast number of minute polygonal 
masses, or lobules, of which the liver is built up; similar 
areas are seen on the surface of any section made through 
the organ. Each lobule (Fig. 101) consists of a number of 


Fro, 101.—A lobule of the liver, magnified, sho ~~ cells radiatety 
arranged wround the ceatrat intralobular vein, and reapillaries Inter 
luced with them, 


hepatic celle supported by a close network of capillaries; 
and is separated from neighboring lobules by connective 
tissue, larger blood-vessels, and branches of the hepatic 
duct. The hepatic ceils are the proper tissue elements of 
tho liver, all the rest being subsidiary arrangements for 
their nutrition and protection. Each is polygonal, nucle- 
ated and very granular, and has a diameter of about .025 
millimeter (y@;5 of an inch). In each lobule they are ar- 
ranged in rows or strings, which intercommunicate and 
form a network, in the meshes of which the blood capilla- 








826 THE HUMAN BODY. 


riesran. Oovering the surface of the liver is a layer of the 
peritoneum, beneath which is a dense connective-tissue 
layer, forming the capsule of Glisson. At the portal fissure 
offsets from this capsule run in, and line canals, the portal 
eanals, which are tunneled through the organs. These, 
becoming smaller and smaller as they branch, finally be- 
come indistinguishable close to the ultimate lobules. From 
their walls and from the external capsule, connective-tissue 
partitions radiate in all directions through the organ and 
support its other parts. In each portal canal lie three ves- 
sels—a branch of the portal yein, a branch of the hepatic 











Tro, 12—A mma! portion of the liver, injected. 
diameters ‘The blood-reasels are represented w! 
lobular vein, rvertying the Intralobular veins, wi 
tho capillaries of tbe fobulen, 


at magnified about twenty 
the large veseel {9 @ sub 
in ture are derived from 






artery, and a branch of the hepatic duct; the division of 
the portal vein being much the largest of the three. These 
vessels break up as the portal canals do, and all end in 
minute branches around the lobules. The blood carried in 
by the portal vein (which has already circulated through 
the capillaries of the-stomach, spleen, intestines and pan- 
ereas) is thus conveyed to a fine vascular inferlobular 
plexus around the liver lobules, from which it flows on 
through the capillaries (lobular plexus) of the lobules them- 
selves, These (Fig. 101) unite in the centre of the lobule 








HEPATIO CIRCULATION. 827 


to form a small infralodular vein, which carries the blood 
out and pours it into one of the branches of origin of the 





Vio, imho stomach. pancreas, Uver, and ih a wl ‘of the rest, 
the mesent 









01 
(lett coronary) of tine stomach’; 3 hopatie artery; 
mesenteric artery 1 6, superior mesenteric veln ; 7, splenic vel 


hepatic yein, called the sudlodular vein. Each of the latter 
has many lobules emptying blood into it, and if dissected out 





928 THE HUMAN BODY. 


with them (Fig. 102) would look something like a branch 
of a tree with apples attached to it by short stalks, repre- 
sented by the intralobular veins. The blood is finally car- 
ried, as above pointed out, by the hepatic veins into the 
inferior vena cava. The hepatic artery, a branch of the 
eceliac axis (p. 211), ends mainly in Glisson’s capsule and 
the walls of the blood-vessels and bile-ducts, but some of 
its blood reaches the lobular plexuses; it all finally leaves 
the liver by the hepatic veins, 

The bile-ducts can be readily traced to the periphery of 
the lobules, and there probably communicate with a minute 
network of commencing bile-ducts ramifying in the lobule 
between the hepatic cells composing it. 

The Pancreas or Sweetbread. ‘This is an elongated 
soft organ of a pinkish yellow color, lying along the great 
curvature of the stomach. Its right end is larger, and 
is embraced by the duodenum (Fig. 103), which there 
makes a curve to the left. A duct traverses the gland and 
joins the common bile-duct close to its intestinal opening. 
‘The pancreas forms a watery-looking secretion which is of 
great importance in digestion. 





CHAPTER XXII. 


THE LYMPHATIC SYSTEM AND THE DUCT- 
LESS GLANDS. 


The Lymphatics or Absorbonts form close networks in 
nearly all parts of the Body. Most organs, as has been 
pointed out (p. 62), possess a sort of internal skeleton made 
up of connective tissue, which consists mainly of bundles of 
fibres, united together and covered in by a ‘‘ cement” sub- 
stance. In this substance are fonnd numerous cavities, 
usually branched, and communicating with one another by 
their branches. They frequently contain connectivo-tissue 
corpuseles, which, however, do not completely fill them; 
and they thus, with their branches, form a set of intercom- 
municating channels known as tho “‘serous canaliculi;” 
these are filled with lymph and constitute the origin of 
lymphatic vessels in many organs. Elsewhere the com- 
mencing ly1 phatics seem to be merely interstices (lacuna) 
between the constituent tissnes of an organ; this is espe- 
cially the case in glands. Such spaces differ from the se- 
rons canaliculi in being lined by a definite epithelium. 

Structure of Lymph-Vessels. The serous canaliculi and 
lymph-spaces open into better defined channels, lined with 
a single layer of wavy-edged flattened epithelial celle. 
‘These form networks in most parts of the Body and are 
known as the lymph capillaries. They are usually wider 
than blood capillaries, From the capillary networks 
larger vessels arise which in structure resemble veins, and 
have similar, but more numerous, valves. 

The Thoracic Duct. All the lymphatics end finally in 
two main trunks which open into the venous system on each 
side of the neck, at the point of junction of the jugular and 





330 THE HUMAN BODY. 





subclavian. The trunk on the right side is much smaller 
than the other and is known as the “right lymphatie duct,” 
Tt collects lymph from the right side of the thorax, from 
the right side of the head and neck, and the right arm. 
The lymph from all the rest of the Body is collected into 
the thoracic duct. It commences at the upper part of the 
abdominal cavity in a dilated reservoir (the receptaculum 
chyli), into which the lacteals from the intestines, and the 
lymphatics of the rest of the lower part of the Body, open. 
From thence the thoracic duct, receiving tributaries on its 
course, rans up the thorax alongside of the aorta and, pass~ 
ing on into the neck, ends on the left side at the point 
already indicated; receiving on its way the main stems 
from the left arm and the left side of the head and neck. 
The thoracic duct, thus, brings back much more lymph 
than the right lymphatic duct, 

‘The Serous Cavities. ‘These are great dependencies of 
the lymphatic system and may be regarded as large laounms, 
Each of them (peritoneal, pleural, arachnoidal and peri- 
cardiac) is lined by a definite epithelioid layer of close-fit- 
ting, hexagonal cells. At certain points, however, openings 
or stomata oceur, surrounded by a ring of smaller cells, and 
leading into tubes which open into subjacent lymphatic 
yeesels. The liquid moistening these cavities is, then, really 
lymph. : 

‘The Lymphatic Glands. These are roundish masses in- 
terposed, at various points, on the course of the lymph-ves- 
sels. They are especially numerous in the mesentery, groin, 
and neck. In the latter position they often inflame and 
give rise to abscesses, especially in scrofulous persons; and 
still more often enlarge, harden, and become more or less 
tender, so as to attract attention tothem. In common jur- 
lance it is then frequently said that the person’s ‘‘ kernels 
have come down,” or that he has “‘ waxing kernels.” Each 
lymphatic gland is enveloped in a connective-tissue capsule, 
and is pervaded by a connective-tissue framework. In the 
meshes of this lie numerous lymph corpuscles, which appear 
to multiply there by division. ‘‘ Afferent” lymphatic vea- 
sels open into the periphery of the so-called gland, and ef- 


x 


MOVEMENT OF THE LYMPH. 831 


forent vessels arise in its centre. Henco, the lymph in its 
flow traverses the cellular gland substance, and in its 
course picks up extra corpuscles which it carries on to the 
blood. In the gland there isa close network of blood capil- 
laries. It is clear that these organs are not glands at all, in 
the proper sense of the word. They are sometimes called 
lymphatic ganglia; but that suggests a false connection with 
nerve-centres. 

The Movement ofthe Lymph. This is no doubt some- 
what irregular in the commencing vessels, but, on the whole, 
sets on to the larger trunks and through them tothe veins. 
Tn many animals (as the frog) at points where the lymphatics 
communicate with the veins, there are found regularly 
contractile “lymph-hearts” which beat with a rhythm inde- 
pendent of that of the blood-heart, and pump the lymph 
intoa vein. In the Human Body, however, there are no 
euch hearts, and the flow of the lymph is dependent on less 
definite arrangements. It seems to be maintained mainly 
by three things. (1) The pressure on the blood plasma in 
the capillaries is greater than that in the great veins of the 
neck; hence any plasma filtered through the capillary walls 
will be under a pressure which will tend to make it flow to 
the venous termination of the thoracic or the right lym- 
phatie duct. (2) On account of the numerous valves in 
the lymphatic vessels (which all only allow the lymph to 
flow past them to larger vessels) any movement compress- 
ing a lymph-vess¢l will cause an onward flow of its contents, 
The influence thus exerted is very important. If a tube be 
put in a large lymph-vessel, say at the top of the leg of an 
animal, it will be seen that the lymph only flows out very 
slowly when the animal is quiet; but as soon as it moves 
its leg the flow is greatly accolerated. (8) During each 
inspiration the pressure on the thoracic duct is less than 
that in the lymphatics in parts of the Body ontside the 
thorax (see Chap. XXTV.). Accordingly, atthat time, lymph 
is pressed, or, in common phrase, is * sucked,” into the 
thoracic duct. During the succeeding expiration the pres- 
sure on the thoracic duct becomes greater again, and some 
of its contents are pressed ont; bnton account of the valves 








332 THE HUMAN BODY. 


they can only go forwards, that is, towards the ending of 
the duct in the veins of the neck. 

During digestion, moreover, the contraction of the villi 
will press on the lymph or chyle; and in certain parts of the 
Body gravity, of course, aids the flow, though it will impede 
it in others, 


The Spleen. There are in the Body several organs of 
such considerable size, and of so great constancy in a large 
number of vertebrate animals, thut they would @ priori 
appear to be of considerable functional importance. What 
their use may be is still, however, unknown or uncertain. 
They are commonly spoken of collectively, along with the 
lymphatic ganglia, as the ductless glands; but they are not 
glands in the proper sense of the word. The spleen is the 
largest of them. It is a red organ situated at the left end 
of the stomach and abont 170 grams (6 oz.) in weight. 
Its size is however very variable; it enlarges during diges- 
tion and shrinks again after it until the next meal. In 
malarial diseases it also becomes enlarged, frequently toa 
very great extent, and then constitutes the so-called *agne- 
cake.” In structure, the spleen consists of a connective- 
tissne ewpsude, rich in elastic fibres, and giving off processes 
which ramify through the organ and form a framework for 
its pulp. The latter contains numerous blood corpuscles; 
and many bodies which seem to be red corpuscles in pro- 
cess of decay or destruction. Hence the spleen has been 
supposed to be a sort of graveyard for their bodies—a place 
where they are broken up and their materials utilized when 
they have run their life eyele. Others, however, consider 
that in the spleen new red blood corpuscles are pro- 
duced from colorless; and others, again, that the main 
function of the organ is the formation of substances which 
are carried off to the stomach and pancreas, to be there 
finally elaborated into digestive ferments. The arteries 
of the spleen open directly into the pulp cavities, from 
which the veins arise, On their walls are rounded whitish 
nodules about the size of a millet-seed, and known as the 





THYMUS AND THYROID. - 833 


Malpighian corpuscles. They resemble tiny lymphatic 
glands in structure. 

Tho Thymus is an organ which only exists in childhood. 
At birth it is found lying around the windpipe, in the upper 

of the chest cavity and the lower part of the neck. It 
increases in size until the end of the second year, and then 
begins to dwindle away, It is grayish pink in color, of a 
soft texture, and, in microscopic structure, resembles some- 
what a lymphatic gland. Hence its function has been sup- 
posed to be the formation of new lymph corpuscles. The 
“‘sweetbread” of butchers is sometimes the pancreas and 
sometimes the thymus of young animals—neck and belly 
sweetbread. 

The Thyroid Body and the Suprarenal Capsules. 
The former of these structures lies in the neck on the sides 
of and below ‘* Adam’s apple.” It is dark red-brown in 
color, and sometimes becomes very much enlarged, as in the 
disease known as goifre. This enlargement appears to be 
often due to drinking water containing magnesian limestone 
in solution, In England, for instance, it is known as ‘‘ Der- 
byshire neck” from being especially frequent in parts of that 
county, where the hills are mainly composed of magnesian 
limestone rocks; and the same geological formation is 
found in those districts of Switzerland where crefinism 
(one of the symptoms of which is an enlarged thyroid 
body) prevails. 

The suprarenal bodies lie one over the top of each kid- 
ney. Their use, like that of the thyroid, is quite pro- 
blematical. In what is known as Addison’s disease (in 
which the skin becomes of a bronze color) it is said that 
these bodies are altered; but it is very improbable that the 
change in them is the actual cause, rather than another 
symptom, of the disease, 














CHAPTER XI. 
DIGESTION. 





The Object of Digestion. Of the various foodstuffs 
ewallowed, some are wlready in solution and ready to dialyze 
at once into the lymphatics and blood-vessels of the alimen- 
tary canal; others, such as a lump of sugar, though not 
dissolved when put into the mouth, are readily soluble in 
the liquids found in the alimentary canal, and need no fur- 
ther digestion. In the case of many most important food- 
stuifs, however, special chemical changes have to be wrought, 
either with the object of converting insoluble bodies into 
soluble, or non-dialyzable into dialyzable, or both. The 
different secretions poured into the alimentary tube act in 
various ways upon different foodstuffs, and at last get them 
into a state in which they can pass into the circulating 
medium and be carried to ull parts of the Body, 

The Saliva. ‘The first solvent that the food meets with 
is the saliva, which, as found in the mouth, is « mixture of 
pure saliva, formed in parotid, submaxillary, and sublingual 
glands, with the mucus secreted by small glands of the oral 
mucousmembrane. This mized saliva is a colorless, cloudy, 
feebly alkaline liquid, “‘ropy” from the mucin present in 
it, and usually containing air-bubbles. Pure saliva, as ob- 
tained by putting a fine tube in the duct of one of the sali- 
vary glands, is less tenacious and contains no imprisoned 
air. 

‘The uses of the saliva are for the most part physical and 
mechanical. It keeps the mouth moist and allows us to 
speak with comfort; most youug orators know the distress 
occasioned by the suppression of the salivary secretion 
nervousness, and the imperfect efficacy under such 













ae 


USES OF SALIVA. 335 


circumstances of the traditional glass of water placed be- 
side public speakers. ‘The saliva, also, enables us to swallow 
dry food; euch a thing us @ cracker when chewed would 
give rise merely to a heap of dust, impossible to swallow, 
were not the month cavity kept moist. This fact used to 
be taken advantage of in the East Indian rice ordeal for 
the detection of criminals. The guilty person, believing 
firmly that he cannot swallow the parched rice given him 
and sure of detection, is apt to have his salivary glands 
paralyzed by fear, and so does actually become unable to 
swallow the rice; while in those with clear consciences the 
nervous system, acting normally, excites the usual reflex 
secretion, and the dry food causes no difficulty of degluti- 
tion. The saliva, also, dissolves such bodies as salt and 
sugar, when taken into the mouth in a solid form, and 
enables us to taste them; undissolved substances are not 
tasted, a fact which any one can verify for himself by 
wiping his tongue dry and placing a fragment of sugar 
upon it. No sweetness will be felt until a little moisture 
has exuded and dissolved part of the sugar. 

Tn addition to such actions the saliva, however, exerts a 
chemical one on an important foodstuff. Starch (although 
it ewells up greatly in hot water) is insoluble, and could 
not be absorbed from the alimentary canal. The saliva 
contains a gpecific element, ptyalin, which has the power 
of turning starch into the readily soluble and dialyzable 
grape sugar. In effecting this change the ptyalin is not 
altered; at least a very small amount of it can cause the 
conversion of a vast amount of starch, and it does not seem 
to have its activity impaired in the process, being still ready 
at the end of it to act upon more. The starch is made to 
combine with the elements of a molecule of water, and the 
ptyalin remains behind as it was— 

CHO’ + HO = CHO 
Starch, Water, Grape sugar. 

Substances acting in this way, producing chemical 
changes without being themselves noticeably altered, aro 
found in many of the digvstive sceretions, and are called 








338 THE HUMAN BODY. 


pharynx, any food which has once entered it must be swal- 
lowed: the isthmus of the fauces forms a sort of Rubicon; 
food that has passed it must continue its course to the 
stomach although the swallower learnt immediately that he 
was taking poison. The third stage of deglutition is that in 
which the food is passing along the gullet, and is compara- 
tively slow. Even liquid substances do not fallor flow down 
this tube, but have their passage controlled by its muscular 
coats, which grip the successive portions swallowed and pass 
themon. Hence the possibility of performing the apparently 
wonderful feat of drinking « glass of water while standing 
upon the head, often exhibited by jugglers: people forget- 
ting that one sees the same thing done every day by horses, 
and other animals, which drink with the pharyngeal end of 
the gullet lower than the stomach. ‘The movements of the 
esophagus are of the kind known as vermicular or peri- 
staltic., Its circular fibres (p. 317) contract behind the morsel 
and narrow the passage there; and the constriction then 
travels along to the stomach, pushing the food in front of 
it. Simultancously the longitudinal fibres, at the point 
where the food-mass is at any moment and immediately in 
front of that, contracting, shorten and widen the passagu. 

The Gastric Juice. The food having entered the sto- 
mach is exposed to the action of the gustric juice, which isa 
thin, colorless, or pale yellow liquid, of a strongly acid re- 
action. It contains as specific elements sree hydrochloric 
acid (about .02 per cent), and an enzyme called pepsin 
which, in acid liquids, has the power of converting the or- 
dinary non-dialyzable proteids which we eat, into the closely 
allied but dialyzable bodies called peptones. It also dis- 
solves solid proteids, changing them too into peptones. 
Dilute acids will by themselves produce the same changes 
in the course of severul days, but in the presence of pepsin 
and at the temperature of the Body the conversion is far 
more rapid. In neutral or alkaline media the pepsin is 
inactive; and cold check sits activity. Boiling destroys it. 
In addition to pepsin, gastric juice contains another enzyme 
which has the power of coagulating the casein of milk, as 
illustrated by the use of “rennet,” prepared from the mu- 





DIGESTION IN THE STOMACH. 839 


cous membrane of the calf’s digestive stomach, in cheese- 
making. The acid of the natural gastric juice might itself, 
it is true, coagulate the casein, but neutralized gastric 
juice still possesses this power; and, since pure solutions of 
pepsin do not, it must be due tosome third body, which has, 
however, not yet been isolated. The curdled condition of 
the milk regurgitated so often by infants is, therefore, not 
any sign of a disordered state of the stomach, as nurses 
commonly suppose. It is natural and proper for milk to 
undergo this change, before the pepsin and acid of the 
gastric juice convert its casein into peptone. 

Gastric Digestion. ‘The process of swallowing is con- 
tinuous, but in the stomach the onward progress of the 
food is stayed for some time. The pyloric sphincter, re- 
maining contracted, closes the aperture leading into the 
intestine, and the irregularly disposed muscular layers of 
the stomach keep its semi-liquid contents in constant 
movement, maintaining a sort of churning by which all 
portions are brought into contact with the mucous mem- 
brane and thoroughly mixed with the secretion of its glands, 
The gelatin-yielding connective tissue of meats is dissolved 
away, and the proteid-containing fibres, left loose, are dis- 
solved and turned into peptones. The albwminous walls 
of the fat-cells are dissolved and their oily contents set 
free; but the gastric juice does not act upon the latter. 
Certain mineral sults (as phosphate of lime, of which there 
is always some in bread) which are insoluble in water but 
soluble in dilute acids, are also dissolved in the stomach. 
On the other hand the gastrie juice has itself no action 
upon starch, and since ptyalin does not act at all, or only 
imperfectly, in an acid medium, the activity of the saliva 
in converting starch is stayed inthe stomach. By the solu- 
tion of the white fibrous connective tissue, that disintegra- 
tion of animal foods commenced by the teeth, is carried 
much farther in the stomach, and the food-mass, mixed 
with much gastric secretion, becomes reduced to the con- 
sistency of a thick soup, usually of a grayish color. In 
this state it is called chyme. This contains, after an ordi- 
nary meal, a considerable quantity of peptones which are 











340 THE HUMAN BODY. 


in great part gradually dialyzed into the blood and lympha- 
tic vessels of the gastric mucous membrane, and carried off, 
along with other dissolved dialyzable bodies, such as salts 
and sugar. After the food has remained in the stomach 
some time (one and a half to two hours) the chyme begins 
to be passed on into the intestine in successive portions. 
The pyloric sphincter relaxes at intervals, and the reat: 
of the stomach, contracting at the same moment, injects a 
quantity of chyme into the duodenum ; this is repeated 
frequently, the larger undigested fragments being at first 
unable to pass the orifice. At the end of about three or 
four hours after a meal the stomach is again quite emptied, 
the pyloric sphincter finally relaxing to a greater extent 
and allowing any larger indigestible masses, which the gas- 
tric juice cannot break down, to be squeezed into the intes- 
tine. 

'The Chyle. When the chyme passes into the duodenum 
it finds preparation made for it. The pancreas is in reflex 
connection with the stomach, and its nerves cause it to 
commence secreting 80 800n as food enters the latter; hence 
a quantity of its secretion is already accumulated in the 
intestine when food enters. The gall-bladder is distended 
with bile, seereted since the last meal; this passing down 
the hepatic duct has been turned back up the cystic duct 
(De, Fig. 100*)on account of the closure of the common 
bile-duct. The acid chyme, stimulating nerve-endings in 
the duodenal mucous membrane, causes reflex contrac- 
tion of the muscular coat of the gall-bladder, and a relaxa- 
tion of the orifice of the common bile-duct; and so a gush 
of bile is poured out on the chyme. From this time on, 
both liver and pancreas continue secreting actively for 
some hours, and pour their products into the intestine, 
‘The glands of Brunner and the crypts of Lieberkiihn are 
also set at work, but concerning their physiology we know 
very little. All of these secretions are alkaline, and they 
suffice very soon to more than neutralize the acidity of the 
gastric juice, and so to convert the acid chyme into alka- 
line chyle, which, after an ordinary meal, will contain a 
great variety of things: mucus derived from the alimen- 


*P. 824. 





PANOREATIG DIGESTION. ‘Bal 


tary canal; ptyalin from the saliva; pepsin from the sto- 
mach; water, partly swallowed and partly derived from the 
salivary and other secretions; the peculiar constituents of 
the bile and pancreatic juice and of the intestinal secretions; 
some undigested proteids; unchanged starch; oils from the 
fats caten; peptones formed in the stomach but not yet 
absorbed; possibly salines and sugar which have also escaped 
absorption in the stomach; and indigestible substances 
taken with the food. 

The Pancreatic Secretion is clear, watery, alkaline, and 
much like saliva in appearance. The Germans call the 
pancreas the ‘abdominal salivary gland.” In digestive 
properties, however, the pancreatic secretion is far more 
important than the saliva, acting not only on starch but, 
also, on proteids and fats. Onstarch it acts like the saliva, 
but more energetically. It produces changes in proteids 
similar to those effected in the stomach, but by the agency 
of a different ferment, ¢rypsin; which differs from pepsin in 


acting only in an alkaline instead of an acid medium. On 
fats it has a double action. ‘Yo a certain extent it breaks 
them up, with hydration, into free fatty acids and glycerine; 
for example— 


(Cul rat 0. +31.0 = 3(OHT Lo) OF | os 
1Stearin ++ SWater « B8tearicacid -+ 1 Glycerine, 


The fatty acid then combines with some of the alkali pres- 
ent to make a soap, which being soluble in water is capable 
of absorption. Glycerine, also, is soluble in water and dialy- 
zuble. The greater part of the fats are not, however, 80 
broken up, but are simply mechanically separated into little 
droplets, which remain suspended in the chyle and give it a 
whitish color, just as the cream-drops are suspended in 
milk, or the olive-oil in mayonnaise sance. This is effected 
by the help of a quantity of albamin which exists dissolved 
in the pancreatic secretion. In the stomach, the animal 
fats eaten have lost their cell-walls, and have become melted 
by the temperature to which they are exposed. Hence 
om their oily part floats free in the chymo when it enters the 








342 THE HUMAN BODY. 


duodenum. If oil be shaken up with water, the two can- 
not be got to mix; immediately the shaking ceases the oil 
floats up tothe top; but if some raw egg be added, a creamy 
mixture is readily formed, in which the oi] remains for a 
long time evenly suspended in the watery menstraum. 
The reason of this is that each oil-droplet becomes sur- 
rounded by a delicate pellicle of albumen, and is thus pre- 
vented from fusing with its neighbors to make large drops, 
which would soon float to the top. Such a mixture is called 
an emulsion, and the albumin of the pancreatic secretion 
emulsifies the oils in the chyle, which becomes white (for the 
same reason as milk is that color) because the innumerable 
tiny oil-drops floating in it reflect all the light which falls 
on its surface. 

The pancreatic secretion thus converts starch into grape 
sugar, dissolves proteids (if necessary) and converts them 
into peptones, emulsifies fats, and, to a certain extent, breaks 
them up into glycerine and fatty acids, which latter are 
saponified by the alkalies present. 

Tho Bilo, Human bile when quite fresh is a golden 
brown liquid; it becomes green when kept. As formed in 
the liver it contains hardly any mucin, but if it makes any 
stay in the gall-bladder it acquires a great deal from the 
lining membrane of that sic, and becomes very “‘ ropy.” 
It is alkaline in reaction and, besides coloring matters, min- 
eral salts, and water, contains the sodium salts of two nitro- 
genized acids, faurocholic and glychocholic, the former pre- 
dominating in human bile. 

Pottenkofer’s Bile Test. If a small fragment of cane 
sugar be added to some bile, and then a large quantity of 
strong sulphuric acid, a brilliant purple color is developed, 
by certain products of the decomposition of its acids; the 
physician can in this way, in disease, detect their presence 
in the urine or other secretions of the Body. Gmelin's 
Bile Test. The dile-coloring matters, treated with yellow 
nitric acid, go through a series of oxidations, accompanied 
with changes of color from yellow-brown to green, then to 
blue, violet, purple, red, and dirty yellow, in succession. 

Bil has no digestive action upon starch or proteids, It 





DIGESTIVE ACTION OF BILE. B48 


does not break up fats, but to a limited extent emulsifies 
them, though far less perfectly than the pancreatic secre- 
tion. It is even doubtful if this action is exerted in the 
intestines at all. In many animals, as in man, the bile and 
pancreatic ducts open together into the duodenum, so that, 
on killing them during digestion and finding emulsified 
fats in the chyle, it is impossible to say whether or no the 
bile had a share inthe process. In the rabbit, however, the 
pancreatic duct opens into the intestine abouta foot farther 
from the stomach than the bile-duct, and it is found that 
if a rabbit be killed after being fed with oil, no milky chyle 
is found down to the point where the pancreatic duct opens. 
In this animal, therefore, the bile alone does not emulsify 
fats, and, since the bile is pretty much the same in it and 
other mammals, it probably does not emulsify fats in them 
either. From the inertness of bile with respect to most 
foodstuffs it has been doubted if it is of any digestive use 
at all, and whether it should not be regarded merely as an 
excretion, poured into the alimentary canal to be got rid of, 
But there are many reasons against such a yiew. In the 
first place, the entry of the bile into the upper end of the 
small intestine where it hus to traverse a course of more 
than twenty feet before getting out of the Body, instead of 

3 being sent into the rectum close to the final opening of 
the alimentary canal, makes it probable that it has some 
function to fulfill in the intestine, Moreover, a great part 
of the bile poured into the intestines is again absorbed from 
them, only a small part being finally excreted; and this also 
seems to show that part of it at least, 1s secreted for some 
other purpose than mere elimination from the Body. One 
use is, no doubt, to assist, by its alkalinity, in overcoming the 
acidity of the chyme, and so to allow the trypsin of the 
ae meoretion to net upon proteids. Constipation as, 


muscular coats of the intestines; and it is 

der similar circumstances putrefactive decom- 
positions are extremely apt to occur in the intestinal eon- 
tents, Apart from such secondary actions, however, the 








Bad THE HUMAN BODY. 


bile probably has some influence in promoting the absorp- 
tion of fats. If one end of a capillary glass tube, moistened 
with water, be dipped in oil, the latter will not ascend in it, 
or but ashort way; but if the tabe be moistened with bile, 
instead of water, the oil will ascend higher in it. So, too, 
oil passes through a plug of porous clay kept moist with bile, 
under a much lower pressure than through one wet with 
water. Hence bile, by soaking the epithelial cells lining the 
intestine, may facilitate the passage into the villi of oily sub- 
stances. At any rate, experiment shows that if the bile be 
prevented from entering the intestine of a dog, the animal 
eats an enormous amount of food compared with that 
amount which it needed previously; and that of this food 
a great proportion of the fatty parts passes out of the ali- 
mentary canal unabsorbed. There is no doubt, therefore, 
that the bile somehow aids in the absorption of fats, but 
exactly how is uncertain. Its possible action in exciting 
the muscles of the villi to contract will be referred to pres- 
ently. Bile precipitates from solution, not only pepsin, but 
any peptones contained in the chyme which enters the in- 
testine from the stomach. 

The Intestinal Secretions or Succus Entericus. This 
consists of the secretions of the glands of Brunner and the 
crypts of Licberkiihn. It is difficult to obtain pure; in- 
deed the product of Brunner’s glands has never been ob- 
tained unmixed. That of the crypts of Lieberkihn is 
watery and alkaline, and poured out more abundantly dur- 
ing digestion than at other times, It has no special action 
on starches, most proteids, or on fats; but is said to dissolve 
blood fibrin and convert it into peptone, and to change cane 
into grape sugar, a transformation the object of which is 
not very clear, since cane sugar is itself readily soluble and 
diffasible. 

Intestinal Digestion. Having considered separately the 
actions of the secretions with which the food meets in the 
small intestine we may now consider their combined effect. 

‘The neutralization of the chyme, followed by its conver- 
sion into alkaline chyle, will prevent any farther action of 
the pepsin on proteids, but will allow the ptyalin of the 





INTESTINAL DIGESTION, 845 


saliva (the activity of which was stopped by the acidity of 
the gastric juice) to recommence its action upon starch. 
Moreover, in the stomach there is produced, alongside of the 
true peptones, a body called parapeptone, which agrees very 
closely with syntonin (p. 126) in its properties, and this 
passes into the duodenum in the chyme. As soon as the 
bile meets the chyme it precipitates the parapeptone, and 
this carries down with it any peptones which, having es- 
caped absorption in the stomach, may be present; it also 
precipitates the pepsin. In consequence, one commonly 
finds, during digestion, a sticky granular precipitate over 
the villi, and in the folds between the valvule conniventes 
of the duodenum, This is soon redissolved by the pancre- 
atic secretion, which also changes into peptones the pro- 
teids (usually a considerable proportion of those eaten at a 
meal) which have passed through the stomach unchanged, 
or in the form of parapeptones. The conversion of starch 
into grape sugar will go on rapidly under the influeuce of 
the pancreatie secretion. Tuts will be split up and saponi- 
fied to a certain extent, but a far larger proportion will be 
emulsified and give the chyle a whitish appearance, Cane 
sugar, which may have escaped absorption in the stomach, 
will be converted into grape sugar and absorbed, along with 
any salines which may, also, have hitherto escaped. Elastic 
tissue from animal substances eaten, cellulose from plants, 
and mucin from the secretions of the alimentary tract, will 
all remain unchanged. 

Absorption from the Small Intestine. Thechymeleay- 
ing the stomach is a semi-liquid mass which, being mixed 
in the duodenum with considerable quantities of pancreatie 
secretion and bile, is still further dilated. henceforth it 
gots the intestinal secretion added to it but, the absorption 
more than counterbalancing the addition of liquid, the food- 
mass becomes more and more solid as it approaches the 
ileo-colic valye. At the same time it becomes poorer in 
nutritive constituents, these being gradually removed from 
it in its progress; most dialyze through the epithelium into 
the subjacent blood and lymphatic vessels, and are carried 
off. Those passing into the blood capillaries are taken by 





346 THE HUMAN BODY, 


the portal vein to the liver; while those entering the lacteals 
are carried into the left jugular vein by the thoracic duet. 
As to which foodstuffs go one road and which the other, 
there is still much doubt; sugars probably go by the portal 
system, while the fats, mainly, if not entirely, go 

the lacteals, How the fats are absorbed is not clear, 
since oils will not dialyze through membranes, such as that 
lining the intestine, moistened with watery liquids. Most 
of them, however, certainly get into the lacteals as oils and 
not as soluble soaps; for one finds these vessels, in a digest- 
inganimal, filled with a beautifully white milky chyle; while 
at other periods their contents are watery and colorless like 
the lymph elsewhere in the Body. The little fat-drops of 
the emulsion formed in the intestine, go through the epi- 
thelial cells and not between them, for during digestion 
one finds these cells loaded with oil-droplets. Now the 
free ends of these cells are striated and probably devoid of 
any definite cell-wall, and it is possible that the intestinal 
movements sqneeze oil-drops into them, which the cell then 
passes on to its deeper end and, thence, out into the sub- 
jacent lymph-spaces, which communicate with the central 
lacteal of a villus. Possibly, too, these cells are ameboid 
and can thrust out processes from their free ends and 
actively pick up the oil-drops. In the villus there are all 
the anatomical arrangements for a mechanism which shall 
actively suck up substances into it. Each is more or less 
elastic, and, moreover, its capillary network when filled with 
blood will distend it. If therefore the muscular stratum 
(p. 821) contracts and compresses it, emptying its lacteals 
into the vessels lying deeper in the intestinal wall, the villas 


its lacteals from the deeper ves- 

sels, on ace alves i ¢ latter, and, accordingly, 
would tend te its materials from the intestines; 
water, after having been 


i ends of t the cells and between 
them; and by) repetitio { the process it is possible that 
considerable quantities of liquid, with suspended ofl-drops, 





DIGESTION IN THE LARGE INTESTINE, 47% 


might be carried into the villus independently of any pro- 
cess of dialysis, The bile moistening the surface of the 
villas may facilitate the passage of oil, as it does through a 
paper filter or a plate of plaster-of-Paris, and it is also said 
to stimulate the contractions of the villi; if so, its efficacy 
in promoting the absorption of fats will be explained, in 
spite of its chemical inertness with respect to those bodies. 

Digestion in the Largo Intestine. The contractions of 
the small intestine drive on its continually diminishing 
contents, until they reach the ileo-colic valve, through which 
they are ultimately pressed. As a rule, when the muss 
enters the large intestine its nutritive portions haye been 
almost entirely absorbed, and it consists merely of some 
water, with the indigestible portion of the food and of the 
secretions of the alimentary canal. It contains cellulose, 
clastic tissue, mucin, and somewhat altered bile pigments; 
commonly some fat if a large quantity has been eaten; and 
some starch, if raw vegetables have formed part of the diet. 
In its progress through the large intestine it loses moro 
water, and the digestion of starch and the absorption of 
fata is continued. Finally the residue, with some excretory 
matters added to it in the large intestine, collects in the 
sigmoid flexure of the colon and in the rectum, and is 
finally sent out of the Body from the latter. 

‘The Digestion of an Ordinary Meal. We may best sum 
up the facts stated in this chapter by considering the diges- 
tion of a common meal; say a breakfast consisting of bread 
and butter, beefsteak, potatoes and mi Many of these 
substances contain several alimentary principles, and, since 
these are digested in different ways and in different parts 
of the alimentary tract, the first thing to be done is to con- 
sider what are the proximate constituents of each. We 
then separate the materials of the breakfast as in the fol- 
lowing table— 





swig aamy30 
te seas eg ibe 
‘wan ¥ 
a 
een 
meg fs" 


oq 
pow WLyngp 














“yeAwAiNy 30 
| “sonn 
awn pout 











ava 
eaeauma00g OUxTENMORT 























DIGESTION OF A MEAL. 349 


From such « meal we may first separate the elastin, cel- 
lulose, and calcium eulphate, as indigestible and passed out 
of the Body in the same state and in the same quantity as 
they entered it, Then come the salines which need no 
special digestion, and, either taken in solution or dis- 
solved in the saliva or gastric jnice, are absorbed from the 
mouth, stomach and intestines without further change. 
Cane and grape sugars experience the same fate, except 
that any cane sugar reaching the intestines before absorp- 
tion, is liable to be changed into grape sugar by the sucens 
entericus. Calcium phosphate will be dissolved by the 
free acid in the stomach, yielding calcium chloride, which 
will be absorbed there or in the intestine, Starch will be 
partially converted into grape sugar during mastication and 
deglutition, and the sugar will be absorbed from the sto- 
mach, A great part of the starch will, however, be passed 
on into the intestine unchanged, since the action of the 
saliva is suspended in the stomach; and its conversion will 
be completed by the pancreatic secretion, and by the ptyalin 
of the saliva, which will recommence its activity when the 
chyle becomes alkaline. The various proteids will be par- 
tially dissolved in the stomach and converted into peptones, 
which will in part be absorbed there; the residue, with the 
undigested proteids, will be passed on to the intestines, 
There the bile will precipitate the peptones and parapep- 
tones and, with the pancreatic secretion, render the chyme 
alkaline, and so stop theactivity of the gastric pepsin. The 
pancreatic secretion will, however, redissolve the precipi- 
tated peptone, and the unchanged proteids and parapeptone, 
and turn the latter into peptones; these will be absorbed as 
they pass along the small intestine; a amall quantity perhaps 
passing into the large intestine, to be taken up there. 
‘The fats will remain unchanged until they enter the small 
intestine, except that the proteid cell-walls of the fats of 
the beefsteak will bo dissolved away. In tho small intes- 
tine these bodies will be partially saponified, but most will 
be emulsified and takon up into the lucteals in that condi- 
tion. Gelatin, from the white fibrous tissue of the beef- 








350 THE HUMAN BODY. 


steak, will undergo changes in the stomach and intestine 
and be dissolved and absorbed. 

‘The substances leaving the alimentary canal after such a 
meal would be, primarily, the indigestible cellulose and 
elastin, together with some water. But there might be in 
addition some unabsorbed fats, starch, and salts, To this 
would be added, in the alimentary canal, mucin, some of 
the ferments of the digestive secretions, some slightly 
altered bile pigments, and other bodies excreted by the 
large intestine. rs 

Dyspepsia is the common name of a number of diseased 
conditions attended with loss of appetite or troublesome 
digestion. Being usually unattended with acute pain, and 
if it kills at all doing so very slowly, it is pre-eminently 
suited for treatment by domestic quackery. In reality, 
however, the immediate cause of the symptoms, and the 
treatment called for, may vary widely; and its detection 
and the choice of the proper remedial agents often call for 
more than ordinary medicul skill. A few of the more com- 
mon forms of dyspepsia may ho mentioned here, with their 
proximate causes, not in order to enable people to under- 
take the rash experiment of dosing themselves, but to show 
how wide a chance there is for any unskilled treatment to 
miss its end, and do more harm than good. 

Appetite is primarily due to a condition of the mucous 
membrane of the stomach which, in health, comes on after 
a short fast, and stimulates its sensory nerves; and loss of 
appetite may be due to either of several causes. The sto~ 
mach may be apathetic and lack its normal sensibility, so 
that the empty condition does not act, as it normally does, 
asa sufficient excitant. When food is taken it is a further 
stimulus and may be enough; in such eases “appetite 
comes with eating.” A bitter before a meal is useful as an 
appetizer to patients of this sort. On the other hand, the 
stomach may be too sensitive, and a voracious appetite be 
felt before a meal, which is replaced by nausea, or even 
yomiting, as soon as a few mouthfuls have been swallowed; 
the extra stimulus of the food then over-stimulates the too 
irritable stomach, just as a draught of mustard and warm 








INDIGESTION. 851 


water will a healthy one. The proper treatment in such 
cases is a soothing one. When food is taken it ought to 
stimulate the sensory gastric nerves, 80 as to excite the reflex 
centres for the secretory nerves, and for the dilatation of 
the blood-vessels, of the organ; if it does not, the gastric 
juice will be imperfectly secreted. In such cases one may 
stimulate the secretory nerves by weak alkalies (p. 336), as 
Apollinaris water or a little carbonate of soda, before meals; 
or give drugs, as strychnine, which increase the irritability 
of reflex nerve-centres. The vascular dilatation may be 
helped by warm drinks, and this is probably the rationale 
of the glass of hot water after eating which has recently 
been in vogue; the usual cup of hot coffee after dinner (the 
desirability of which is proved by the consensus of civilized 
mankind) is a more agreeable form of the same aid to 
digestion. In states of general debility, when the stomach 
is too feeble to secrete under any stimulation, the adminis- 
tration of weak acids and artificially prepared pepsin is 
needed, 80 a3 to supply gastric juice from outside, until the 
improved digestion strengthens the stomach up to the 
point of being able to do its own work, 

Enough has probably been said to show that dyspepsia 
is not a disease, but a symptom accompanying many patho- 
logical conditions, requiring special knowledge for their 
treatment. From its nature—depriving the Body of its 
proper nourishment—it tends to intensify itself, and so 
should never be neglected; a stitch in time saves nine, 





CHAPTER XXIV. 
THE RESPIRATORY MECHANISM. 


Definitions. The blood as it flows from the right yen- 
tricle of the heart, through the lungs, to the left auricle, 
loses carbon dioxide and gains oxygen. In the systemic 
circulation exactly the reverse changes take place, oxygen 
leaving the blood to supply the living tissues and carbon 
dioxide, generated in them, passing back into the blood 
capillaries. The oxygen loss and carbon dioxide gain are 
associated with « change in the color of the blood from 
bright scarlet to purple red, or from arterial to venous; and 
the opposiie changes in the lungs restore to the dark blood 
its bright tint. ‘The whole set of processes through which 
blood becomes venous in the systemic circulation and 
arterial in the pulmonary—in other words the processes 
concerned in the gaseous reception, distribution and elimi- 
nation of the Body—constitute the function of respiration; 
so much of this as is concerned in the interchanges between 
the blood and air being known as eternal respiration; 
while the interchanges occurring in the systemic capillaries, 
and the processes in general by which oxygen is fixed and 
carbon dioxide formed by the living tissues, are known as 
internal respiration. When the term respiration is used 
alone, without any limiting adjective, the external respira- 
tion only, is commonly meant. 

Respiratory O: ns, ‘The blood being kept poor in 

bon dioxide by the action of the liy- 
ing tissues, a certain amount of gaseous interchange will 
nearly ulways take place when it comes into close proximity 
to the surrounding medium; whether this be the atmos- 
phere itself or water containing air in solution, When an 





~ RESPIRATORY ORGANS. 853 


animal is small there are often no special organs for its ex- 
ternal respiration, its general surface being sufficient (espe- 
cially in aquatic animals with a moist skin) to permit of all 
the gaseous exchange that is necessary. In the simplest 
creatures, indeed, there is even no blood, the cell or cells 
composing them taking up for themselves from their en- 
vironment the oxygen which they need, and passing out 
into it their carbon dioxide waste; in other words, there ix 
no differentiation of the external and internal respirations, 
When, however, an animal is larger many of its cells are so 
far from a free surface that they cannot transact this give- 
and-take with the surrounding medium directly, and the 
blood, or some liquid representing it in this respect, serves 
as a middleman between the living tissues and the external 
oxygen; and then one usually finds special respiratory or- 
gans developed, into which the blood is brought to replace 
its oxygen logs and get rid of its excess of carbon dioxide. 
Tn aquatic animals such organs take commonly the form 
of gills; these are protrusions of the body over which a 
conatant current of water, containing oxygen in solu- 
tion, is kept up; and in which blood capillaries form a 
close network immediately beneath the anrface. In air- 
breathing animals a different arrangement is usually found. 
In some, as frogs, it is true, the skin is kept moist and 
serves a8 an important respiratory organ, large quanti- 
ties of venous blood being sent to it for aération. Bat for 
the occurrence’ of the necessary gaseous diffusion, the skin 
must be kept very moist, and this, in a terrestrial animal, 
necessitates a great amount of secretion by the cutaneous 
glands to compensate for evaporation; and accordingly in 
land animals the air is usually carried into the body by 
tubes with narrow external orifices, and so the drying up of 
the breathing surfaces is greatly diminished; just as water 
in a bottle with a narrow neck will disappear much more 
slowly than the same amount exposed in an open dish. In 
insects (as bees, butterflics, and beetles) the air is carried 
by tubes which split up into extremely fine branches and 
ramify all ths. 1gh the body, even down to the individual 
tissue elements, which thus carry on their gnscaus exchanges 








354 THE HUMAN BODY. = 


without the intervention of the blood. But in the great 
muajority.of air-breuthing animals the arrangement is dif- 
ferent; the air-tubes leading from the exterior of the body 
do not subdivide into branches which ramify all through it, 
but open into one or more large sacs to which the yenous 
blood is brought, and in whose walls it flows through 
a close capillary network, Such respiratory sacs are called 
fungs, and it. is a highly developed form of them which is 
employed in the Human Body, 

‘The Air-Passages and Lungs. In our own Bodies some 
small amount of respiration is carried on in the alimentary 
canal, the air swallowed with 
food or saliva undergoing gas- 
cous exchanges with the blood 
in the gastric and intestinal mu- 
cous membranes, The amount 
of oxygen thus obtained by the 
blood is however very trivial, as 
is that absorbed through the 
skin, covered as it is by its dry 
horny non-vascular epidermis. 
All the really essential gaseous 
interchanges between the Body 
and the atmosphere take place 
in the lungs, two large sacs (2, 
Fig. 1) lying in the thoracic 
cayity, one on each side of the 
heart, To these sacs the air is 

Fro. 104.—The lungs and air-par conveyed through a series of 
RE ae Me passages. Entering the pharynx 


tissue han been disectedt away to 2 H 
stow theramificationsot tho bron. through the nostrils or mouth, 


ov incrng: b tmebea: it passes out of this by the open- 
seen entering the root ofits ing leading into the larynx, or 

yoice-box (a, Fig. 104), lying in 
the upper part of the neck (tho communication of the two 
is seen in Fig. 89); from tho larynx passes back the 
trachea or windpipe, b,which, after entering the chest cavity, 
divides into the right and left brouchi, d. Each bronchus 
divides up into smaller and smaller branches, called bron- 




















STRUCTURE OF THE LUNGS. ‘B55 


chial tubes, within the Jung on its own side; and the smallest 
bronchial tubes end in sacculated dilatations, the alveoli of 
the lungs, the sacculations (Fig. 106) being the air-cells: 
the word “cell” being here used. ’ 
in its primitive sense of a small 
cavity, and not in its later tech~ 
nical signification of a morpho- 
logical unit of the Body, On 
the walls of the air-cells the 
pulmonary capillaries ramify, 
and it is in them that the inter- 
changes of the external respira- y,, 195 4 gmat bronchial tube, 
tion take place. a, dividing § Pay ranch: 
Structure of the Trachea inci alls apd end tn the sxceu- 
and Bronchi. The windpipe ™ 
may readily be felt in the middle line of the neck, a little 
below Adam’s apple, as 4 rigid cylindrical mass, Tt con- 
sists fundamentally of a fibrous tube in which cartilages 
are imbedded, so as to keep it from collapsing; and is lined 
internally by a mucous membrane covered by several layers 
of epithelium cells, of which the superficial is ciliated (Fig. 
47), The cartilages imbedded in its walls are imperfect 
rings, each somewhat the shape of a horseshoe and, tho 
deficient part of each ring being turned backwards, it comes 
to pass that the deeper or dorsal side of the windpipe has 
no hard parts in it, Against this side the gullet lies, and 
the absence there of the cartilages no doubt facilitates swal- 
lowing. The bronchi resemble the windpipe in structure, 
Tho Structure of the Lungs, These consist of the 
bronchial tubes and their terminal dilatations; numerous 
blood-vessels, nerves and lymphatics; and an abundance of 
connective tissue, rich in elastic fibres, binding all together. 
The bronchial tubes ramify in atree-like manner (Pig. 104), 
Tn structure the larger ones resemble the trachea, except 
that the cartilage rings are not regularly arranged so as to 
have their open parts all turned one way, As the tubes 
become smaller their constituents thin away; the cartilages 
become less frequent and finally disappear; the epithelium 
is reduced to a single layer of cells which, though still cili« 








356 THE HUMAN BODY. 


ated, are much shorter than the columnar superficial cell 
layer of the larger tubes. The terminal alveoli (a, a, Fig. 
106,) and the air-cells, 6, which open into them, haye walls 
composed mainly of elastic tissue and lined by a single 
layer of flat, non-ciliated epi- 
thelium,immediately beneath 
which is a very close network 
of capillary blood ~ vessels. 
The air entering by the bron- 
chial tube is thus only sepa- 
rated from the blood by the 
thin capillary wall and the 
thin epithelinm, both of 
which are moist, and well 
adapted to permit gaseous 
diffusion. 

Tho Ploura, Each lung 
is covered, except at one 





Fro, 100.—Twroalveolt of tho Iung 
Righty b, b the air-cell 

Sctlow frotrasions et the jalvoolus, 
opening tata Htxcentral cavity 6, ter” 


point, by an elastic serous 
membrane which adheres 
tightly to it and is called the 


hes of & bronchial tube. 


pleura; that point at which 
the pleura is wanting iscalled the roofof the lung and is 
on its inner side; it is there that its bronchus, blood-vessels 
and nerves enter it. At the root of the lung the pleura 
turns back and lines the inside of the chest cavity, as rep- 
resented by the dotted line in the diagram Fig. 1. The 
part of the pleura attached to each lung is its wtsceral, and 
that attached to the chest-wall its parietal layer. Each 
pleura thus forms aclosed sac surrounding a plenral cavity, 
in which, during health, there are found a few drops of 
lymph, keeping its surfaces moist. This lessens friction 
between the two layers during the movements of the chest- 
wallsand the lungs; for although, to insure distinctness, 
the visceral and parietal layers of the pleura are represented 
in the diagram as not in contact, that is not the natural 
condition of things; the lungs are in life distended so that 
the visceral pleura rubs against the parictal, and the pleural 
cavity is practically obliterated. This is brought about by 





WAY THE LUNGS DO NOT COLLAPSE. BAT 


the pressure of the atmosphere on the inside of the Inngs, 
through the air-passages, The lungs are extremely elastic 
and distensible, and when the chest cavity is perforated 
each shrivels up just as an mdian-rubber bladder does when 
its neck is opened; the reason being that then the air 
presses on the ontside of each with as much force as it does 
on the inside. hese two pressures neutralizing one an- 
other, there is nothing to overcome the tendency of the 
Inngs to collapse, So long as the chest-walls are whole, 
however, the lungs remain distended. ‘The plenral sac is 
air-tight and contains no air, and the pressure of the air 
around the Body is borne by the rigid walls of the chest 
and prevented from reaching the lungs; consequently no 
atmospheric pressure is exerted on their outsides. On their 
interior, however, the atmosphere presses with its full 
weight, equal (see Physics) to about 90 centigrams on # 
square centimeter (14.5 Ibs. on the square inch), and this 
is far more than sufficient to distend the 

Jungs go as to make them completely fill 

all the parts of the thoracic cavity not 

occupied by other organs. Suppose A, 

(Big. 107) to be a bottle closed air-tight 

by a cork through which two tubes pass, 

one of which, }, leads into an elastic bag, 

d, and the other, ¢, provided with a stop- 

cock, opens freely below into the bottle, 

If the stop-oock, ¢, is open the air will | Fro. 107—Diagram 
enter the bottle and press there on the Re 
outside of the bag, as well as on its in- nes 
side through 4. The bag will therefore 

collapse, as the Iungs do when the chest cavity is opened. 
But if some air be sacked out of ¢ the pressure of that remain- 
ing in the bottle will diminish, while that inside the bag 
will be the same, and the bay will thus be blown up, because 
the atmospheric pressure on its interior will not be balanced 
by that on its exterior. At last, whon all the air is sucked 
out of the bottle and the stop-cock on ¢ closed, the bag, if 
sufficiently distensible, will be expanded until it completely 
fills the bottle and presses against its inside, and the state 











358 THE HUMAN BODY. 


of things will then answer to that naturally found in the 
chest. If the bottle were now increased in size without 
letting air into it, the bag would expand still more, so as to 
fill it, and in so doing would receive air from outside 
through 4; and if the bottle then returned to its original 
size, its walls would preas on the bag and cause it to shrink 
and expel some of its air through 6. Exactly the same 
must of course happen, under similar cireumstances, in the 
chest, the windpipe answering to the tabe 4 through which 
air enters or leaves the elastic sac. 

The Respiratory Movements. ‘The air taken into the 
Tangs soon becomes laden in them with carbon dioxide, and 
at the same time loses much of its oxygen; these inter- 
changes taking place mainly in the deep recesses of the 
alveoli, far from the exterior, and only communicating with 
it through a long tract of narrow tubes. The alveolar air, 
thus become unfit: to any longer convert venous blood into 
arterial, could only very slowly be renewed by gaseous dif- 
fusion with the outer air through the long air-passages— 
not nearly fast enough for the requirements of the Body, as 
any one readily experiences throngh the sensation of suffo- 
cation which follows holding the breath for a very short 
time. Consequently, added on to the breathing lungs is a 
respiratory mechanism, by which the air within them is 
periodically mixed with fresh air taken from the outside, 
and also the air in the alveoli is stirred up 80 a8 to bring 
fresh layers of it in contact with the walls of the air-cells. 
This mixing is bronght about by the breathing movements, 
consisting of regularly alternating tnsptrations, during 
which the chest cavity is enlarged and fresh air enters the 
lungs, and expirations, in which the cavity is diminished 
an expelled from the lungs. When the chest is enlarged 
the air the lungs contain immediately distends them so as 
to fill the larger space; in so doing it become rarefied and 
Jess dense than the external air; and since gases flow from 
points of greater to those of loss pressure, some outside air 
at once flows in by tho air-passages and enters the lungs. 
Ih expiration the reverse takes place. The chest cavity, 
diminishing, presses on the lungs and makes the air inside 











MOVEMENTS OF THE THORAX. 359 


them denser than the external air, and so come passes out 
until an equilibrium of pressure is restored. The chest, in 
fact, acts very much like a bellows. When the bellows are 
opened air enters in con- 
sequence of the rarefaction 
of that in the interior, 
which is expanding to fill 
the larger space; and when 
the bellows are closed 

again it is expelled, To ee Se at Tenah en te Coe 
make the bellows quite ‘*!¥ emarees 

like the lungs we must, however, as in Fig 108, have only 
one opening in them, that of the nozzle, for both the entry 
and exit of the air; and this opening should lead, not 
directly into the bellows cavity, but into an clastic bag 
lying in it, and tied to the inner end of the nozzle-pipe. 
‘This sac would represent the lungs and the space between 
its outside, and the inside of the bellows, the pleural cavi- 
thes. 

We have next to see how the expansion and contraction 
of the chest cavity are brought about. 

Tho Structure of the Thorax. The thoracic cavity has 
a conical form determined by the shape of its skeleton (Fig. 
109), its narrower end being turned upwards, Dorsally, 
ventrally, and on the sides, it is supported by the rigid 
framework afforded by the dorsal vertebra, the breast-bone, 
and the ribs. Between and over these lie muscles, and the 
whole is covered in, air-tight, by the skin externally, and the 
parietal layers of the pleure inside. Above, its aperture is 
closed by muscles and by various organs passing between 
the thorax and the neck; and below it is bounded by the 
diaphragm, which forms « movable bottom to the, other- 
wise, tolerably rigid box. In inspiration this box is in- 
creased in all its diameters—dorso-ventrally, laterally, and 
from above down. 

The Vertical Enlargement of the Thorax. This is 
brought about by the contraction of the diaphragm which 
(Figs. 1 and 110) is a thin sheet-like muscle, with a fibrous 
membrane, serving as atendon, in its contre. In rest, the 











360 THE HUMAN BODY. 


diaphragm is dome-shaped, its concavity being turned 
towards the abdomen. From the tendon on the crown of 
the dome striped muscular fibres radiate, downwards and 
outwards, to all sides; and are fixed by their inferior ends 
to the lower ribs, the breast-bone, and the vertebral column. 
Tn expiration the lower lateral portions of the diaphragm 
lie close against the chest-walls, no lang intervening between 
them. In inspiration the muscular fibres, shortening, flat- 





aria 1005 The Ceeepae ot the thorax a, 9, vertebeal calumny b firat rib; ¢ 
ten the dome and so enlarge the thoracic cavity at the ex- 
pense of the abdominal; and at the same time its lateral 
portions are pulled away from the chest-walls, leaving a 
space into which the lower ends of the lungs expand. The 
contraction of the diaphragm thus increases greatly thesize 
of the thorax chamber by adding to its lowest and widest 

part. 
‘The Dorso-Ventral Enlargement of the Thorax. The 
ribs on the whole slope downwards (/, Fig. 25) from the 
bral column to the breast-bone, the slope being most 











THE ENLARGEMENT OF THE THORAX. 361 


marked in the lower ones. During inspiration the breast- 
bone and the sternal ends of the ribs attached to it are 








‘Fis. 110.The diaphragm seen from below, 


raised, and so the distance between the sternum and the 
vertebral column is increased. ‘That this must be so will 
readily be seen by examining the diagram Fig. 111, where 
ab represents the vertebral column, 
e and d two ribs, and sf the ster- 
num. The continuous lines repre- 
sent the natural position of the ribs 
at rest in expiration, and the dotted 
lines the position in inspiration. It 
is clear that when their lower ends 
are raised, so as to make the bars lie 
in a more horizontal plane, the ster- 
num is pushed away from the spine, 
und so the chest cavity is increased 
dorso- ventrally. The inspiratory 
elevation of the riba ia mainlydue to 
the action of the scalene and exter- 
nal intercostal muscles, ‘The scalene muscles, three on each 
side, arise from the cervical vertebre and are inserted into 

















362 THE HUMAN BODY. 


the upper ribs. The external intercostals (Fig. 112, A) lie 
between the ribs and extend from the vertebral column to the 
costal cartilages; their fibres slope downwards and forwards. 
During an inspiration the sealenes contract and fix the 
upper ribs firmly; then the external intercostals shorten 
and each raises the rib below it. The muscle, in fact, 
tends to pull together the pair of ribs between which it 
lies, but as the upper one of these is held tight by the 





Fro, 118. Porsions of four ribs of a dog with the muscles hetween them. a. a. 

Neutral eas of the ribs, Jolning at othe rib cartilages, b, which are ficod to 

fnous portions, dof the aternuin, 4, external lutercostal muscle, cas 

o4, Where the internal intercostal, £. isseen, Between 

rhal intercostal muscle has been dissected away, so 
hich was covered by It. 






ing between the rib e 
the maddie two ribs 
‘as to display the intern 





scalenes and other muscles above, the result is that the lower 
rib is pulled up, and not the upper down. In this way the 
lower ribs are raised much more than the upper, for the 
whole external intercostal muscles on one side may be re- 
garded as one great muscle with many bellies, each belly 
separated from the next by a tendon, represented by the 
rib, When the whole muscular sheet is fixed above and 





MECHANISM OF EXPIRATION. 363 


contracts, it is clear that its lower end will be raised more 
than any intermediate point, since there is a greater length 
of contractile tissue above it. The elevation of the ribs 
tends to diminish the vertical diameter of the chest; this is 
more than compensated for by the simultaneous descent of 
the diaphragm. 

The Lateral Enlargement of the Chest is mainly due 
to the diaphragm, which, when it contracts, adds to the 
lowest and widest part of the conical chest cavity. Some 
small widening is, however, brought about by a rotation of 
some of the middle ribs which, as they are raised, roll round 
a little at their vertebral articulations and twist their car- 
tilages. ach rib is curved and, if the bones be examined 
in their natural position in a skeleton, it will be seen that 
the most curved part lies below the level of a straight line 
drawn from the vertebral to the sternal attachment of the 
bone. By the rotation of the rib, during inspiration, this 
carved part is raised and turned out, and the chest widened. 
The mechanism can be understood by clasping the hands 
opposite the lower end of the sternum and a few inches in 
front of it, with the elbows bent and pointing downwards, 
Each arm will then answer, in an exaggerated way, to a 
curved rib, and the clasped hands to the breast-bone. If 
the hands be simply raised a few inches by movement at the 
shoulder-joints only, they will be separated farther from the 
front of the Body, and rib elevation and the consequent 
dorso-ventral enlargement of the cavity surrounded will be 
represented, But if, simultaneously, the arms be rotated at 
the shoulder-joints so as to raise the elbows and turn them 
out a little, it will be seen that the space snrrounded by the 
two arms is considerably increased from side to side, as the 

is in inspiration by the similar elevation of the 
most curved part or *‘ angle” of the middle riba. 

Expiration. To produce an inspiration requires con- 
siderable muscular effort, The ribs and sternum have to 
be raised; the elastic rib cartilages bent and somewhat 
twisted; the abdominal viscera pushed down; and the ab- 
dominal wall pushed out to make room for them. In ex- 
piration, on the contrary, but little, if any, muscular effort 








364 THE HUMAN BODY. 


is needed. As soon as the muscles which have raised the 
ribs and sternum relax, these tend to return to their natural 
unconstrained position, and the rib cartilages, also, to wn- 
twist themselves and bring the ribs back to their position 
of rest; the elastic abdominal wall presses the contained 
viscera against the under side of the diaphragm, and pushes 
that up again as soon as its muscular fibres cease contract 
ing. By these means the chest cavity is restored to its 
original capacity and the air sent out of the lungs, rather 
by the elasticity of the parts which were stretched in inspir- 
ation, than by any special expiratory muscles. 

tion. When avery deep breath is drawn 
or expelled, or when there is some impediment to the entry 
or exit of the air, a great many muscles take part in pro- 
ducing the respiratory movements, and expiration then be- 
comes, in part, an actively muscular act. ‘The main expira- 
tory muscles are the inéernal intercostals which lie beneath 
the external between each pair of ribs (Fig. 112, 2), and 
have an opposite direction, their fibres running upwards 
and forwards. In forced expiration the lower ribs are fixed 
or pulled down by muscles ranning in the abdominal wall 
from the pelvis to them and to the breast-bone. ‘The in- 
ternal intercostals then contracting, pull down the upper 
ribs and the sternum, and 50 diminish the thoracic cavity 
dorso-ventrally. At the same time, the contracted abdomi- 
nal muscles press the walls of that cavity against the viscera 
within it, and pushing these up forcibly against the din- 
phragm make it very convex towards the chest, and so 
diminish the latter in its vertical diameter. In very violent 
expiration many other muscles may co-operate, tending to 
fix points on which those muscles which can directly dimin- 
ish the thoracic cavity, pull. In violent inspiration, also, 
many extra muscles are called into play. The neck is held 
rigid to give the scalenes a firm attachment; the shoulder- 
joint is held fixed and museles going from it to the chest- 
wall, and commonly serving to move the arm, are then 
used to elevate the ribs; the head is held firmon the verte- 
bral column by the muscles going between the two, and 
then other muscles, which pass from the collar-bone and 











ail 


CAPACITY OF THE LUNGS, 865 


sternum to the skull, are used to pull up the former. The 
muscles which are thus called into play in labored but not 
in quiet breathing are called extraordinary muscles of res- 
piration. 

‘Phe Respiratory Sounds. The entry and exit of air 
are accompanied by respiratory sounds or murmurs, 
which can be heard on applying the ear to the chest wall. 
‘The character of these sounds is different and characteristic 
over the trachea, the larger bronchial tubes, and portions 
of lung from which large bronchial tubes are absent. ‘They 
are yariously modified in pulmonary affections and hence 
the value of auscultation of the lungs in assisting the phy- 
sician to form a diagnosis. 

The Capacity of the Lungs, Since the chest cavity 
never even approximately collapses, the lungs are never 
completely emptied of air: the space they have to occupy 
is larger in inspiration than during expiration but is always 
considerable, so that after a forced expiration they still con- 
tain a large amount of air which can only be expelled from 
them by opening the pleural cavities; then they entirely 
collapse, just as the bag in Fig. 107 would if the bottle in- 
closing it were broken. ‘The capacity of the chest, and 
therefore of the lungs, varies much in different individuals, 
but in a man of medium height there remains in the lungs 
after the most violent possible expiration, about 1640 cub, 
cent, (L00 cub. inches) of air, called the residual air. 
After an ordmary expiration there will be in addition to 
this about as much more supplemental air; the residual and 
supplemental together forming the stationary air, which 
remains in tho chest during quiet breathing. In an ordi- 
nary inspiration 600 cub. cent, (30 cub. inches) of tidal air 
are taken in, and about the same amount is expelled in nat- 
ural expiration, By a forced inspiration about 1600 cub, 
cent. (98 cub. inches) of complemental air can be added to 
the tidal air. After a forced inspiration therefore the chest 
will contain 1640 + 1640 +- 500 + 1600 = 5380 cubic centi- 
meters (328 cubic inches) of air, The amount which can 
be taken in by the most violent possible inspiration after 
the strongest possible expiration, that is, the supplemental, 








366 THE Hi MAN BODY, 


tidal and complemental air together, is known as the vital 
capacity. For « healthy man 1.7 meters (5 feet 8 inches) 
high it is about 3700 cub. vent. (225 cub. inches) 
and increases 60 cub. cent. for each additional centime- 
ter of stature; or about 9 cubic inches for each inch of 
height. 

The Quantity of Air Breathed Daily. Knowing the 
quantity of air taken in at each breath and expelled again 
(after more or less thorough mixture with the stationary 
air) we have only to know, in addition, the rate at which the 
breathing movements occur, to be able to caleulate how 
much air passes through the lungs in twenty-four hours. 
The average number of respirations in a minute is found 
by counting on persons sitting quietly, and not knowing 
that their breathing rate ia under observation, to be fifteen 
inaminute. In each of these half a liter (30 eubic inches) 
of air is concerned; therefore 0.5 x 15 x 60 x 24 = 10,800 
liters (374 cubic feet) is the quantity of air breathed under 
ordinary circumstances by each person in a day. 

Hygienic Remarks. Since the diaphragm when it con- 
tracts pushes down the abdominal viscera beneath it, these 
haye to make room for themselves by pushing out the soft 
front of the abdomen which, accordingly. protrudes when 
the diaphragm descends. Hence breathing by the din- 
phragm, being indicated on the exterior by movements of 
the abdomen, is often called ‘abdominal respiration,” as 
distinguished from breathing by the ribs, called * costal” 
or “chest breathing.” In both sexes the diaphragmatic 
breathing is the most important, but, as a rule, men and 
children use the ribs less than adult women. Since both 
abdomen and chest alternately expand and contract in 
healthy breathing anything which impedes their free move+ 
ment is to be avoided; and the tight lacing which used to 
be thought elegant a few yeurs back, and is still indulged 
in by some who think a distorted form beautiful, seriously 
impedes one of the most important functions of the Body, 
leading, if nothing worse, to shortness of breath and an in- 
capacity for muscular exertion. In extreme cases of tight 
lacing some organs are often dircetly injured, weals of 








| 





ASPIRATION OF THE THORAX. B67 


fibrous tissue being, for example, not unfrequently found 
developed on the liver, from the pressure of the lower ribs 
forced against it by a tight corset. 

The Aspiration of the Thorax, Asalready pointed out, 
in consequence of the rigid framework which supports its 
walls, the external air cannot press directly upon the con- 
tents of the thoracic cavity. It still, however, presses on 
them indirectly, through the lungs. Acting on the interior 
of these with a pressure equal to that exerted on the same 
area by a column of mercury 760 mm. (30 inches) high, it 
distends them, and pushes them against the inside of the 
chest-walls, the heart, the great thoracic blood-vessels, the 
thoracic duct, and the other contents of the cavity. The 
pressure thus exerted is not equal to that of the external 
air, since some of the total air-pressure on the inside of the 
lungs is used up in overcoming their elasticity, and it is only 
the residue which pushes them against the things outside 
them. In expiration this residue is about equal to that ex- 
erted bya colamn of mereury 754 mm. (} inch less than be- 
fore) high. On most parts of the Body the atmospheric 
pressure can, however, act with full force. Pressing on a 
limb it pashes the skin aguinst the soft parts beneath, and 
these against the blood and lymph vessels among them; 
and the yielding abdominal walls do not, like the rigid 
thoracic walls, carry the atmospheric pressure themselves 
but transmit it to the contents of the cavity. It thus 
comes to piss that the blood and lymph in most parts of 
the Body are under a higher atmospheric pressure than in 
the chest, and consequently these liquids tend to flow into 
the thorax, nutil the extra distension of the vessels in which 
they there accumulate compensates for the less external 
pressure to which those vessels are exposed. An equili- 
brium would thus very soon be brought about were it not 
for the respiratory movements, in consequence of which the 
intra-thoracic pressure is alternately increased and dimin- 
ished, and the thorax comes to act asasort of suction-pump 
on the contents of the vessels of the Body outside it; 
thus the respiratory movements come to influence the cir- 
culation of the blood and the flow of the lymph. 





868 THE HUMAN BODY. 


Influence of the Respiratory Movements upon the 
Circulation. Suppose the chest in a condition of natural 
expiration and the external pressure on the blood in the 
blood-vessels within it, and in the heart, to have come, in 
the manner pointed out in the last paragraph, into equili- 
brium with the atmospheric pressure on the blood-yessels of 
the neck and abdomen. If an inspiration now occurs, the 
chest cavity being enlarged the pressure on all of its con- 
tents will be diminished. In consequence, air enters the 
lungs from the windpipe, and blood enters the ven cayw 
and the right auricle of the heart. Not only the lungs, 
then, but the right side of the heart, and the intra-thoracie 
portions of the systemic veins leading to it, are expanded 
during an inspiration; but the lungs being much the most 
distensible take far the greatest. part in filling up the in- 
creased space. The left side of the heart is not much in- 
fluenced as it is filled from the pulmonary yeins; and the 
whole vessels of the lesser circulation lying within the 
chest, and being all affected in the same way at the same 
time, the blood-flow in them is not influenced by the aspi- 
ration of the thorax. Distension of the Inngs seems, how- 
ever, fo diminish the capacity of their vessels, and 90 to a 
certain extent the flow is influenced; as the lungs expand 
blood is forced out of their vessels into the left auricle, and 
when they again contract their vessels fill up from the right 
yentricle. The pressure on the thoracic aorta being dimin- 
ished in inspiration, blood tends to flow back into it from 
the abdominal portion of the vessel, but cannot enter the 
heart on account of the semilunar valves; and the back-flow 
does not in any ease equal the onflow due to the beat of the 

t in the aorta is but a slight 

e general result of all this is 

iderably assisted. When the 

‘in the thorax again 

rises, aii | to be led from the cavity. 

The aorta thu lost during inspiration; the 

pressure on it is 

its abdominal portion. 





EFFECT OF RESPIRATION ON BLOOD-FLOW, 369 


vented any regurgitation into the heart, there is neither 
gain nor loss so far as it is concerned. With the systemic 
mtrathoracic veins, however, this is not the case; the extra 
blood entering them has already in great part gone on be- 
yond the tricuspid valye, and cannot flow back during ex- 
piration; and the pressure in the auricle being constantly 
kept low by its emptying into the ventricle, the increased 
pressure on the vense cava tends as much to send the blood 
on into the heart, as back into the extra-thoracic veins. 
Moreover, whatever blood tends to take the latter course 
cannot do it effectually since, although the vena cava 
themselves contain no valves, the more distant veins which 
open into them do. Consequently, whatever extra blood 
has, to use the common phrase, been “sucked” into the 
intra-thoracic yen cave in inspiration and has not been 
sent already on into the right ventricle before expiration 
oceurs, 1s, on account of the venous valves, imprisoned in 
the cave under an increased pressure during expiration; 
and this tends to muke it flow faster into the auricle during 
the diastole of the latter. How much the alternating res- 
piratory movements assist the venous ‘flow is shown by the 
dilation of the veins of the head and neck which occurs 
when a person 1s holding his breath; and the blackness for 
the face, from distension of the veins and stagnation of the 
capillary flow, which occurs during a prolonged fit of cough- 
ing, which is # series of expiratory efforts without any in- 
spirations, 

In still another way the aspiration of the thorax assists 
the heart. The heart and lungs are both extensible, thongh 
in different degrees, and cach is stretched in the chest 
somewhat beyond its natural size; the one by the atmos- 
pheric pressure directly, the other by that pressure in- 
directly, exerted through the blood exposed to it in the 
extra-thoracic veins. Supposing, therefore, the heart sud- 
denly to shrink it would leave more space in the chest to be 
filled by the lungs, and these, accordingly, at each cardiae 
systole expand a little to fill the extra room, just as they do 
when the space around them is otherwise enlarged during 











870 THE HUMAN BODY. 


an inspiration. The olasticity of the Inngs, however, 
causes them to resist this distension and oppose the cardiac 
systole. The matter may be made clear by an arrangement 
like that in Fig, 113. 4 is an air-tight vessel with a tubo, 
¢, provided with a stop-cock, leading from it; 6 is a highly 
distensible elastic bag in free communication through d 
with the exterior; and ¢, representing 
the heart, is a less extensible sac, from 
which a tube leads and dips under 
water in the vessel B. If air be 
pumped out through ¢ both bags will 
dilate, 4 filling with air, and ¢ with 
water driven up by atmospheric pres- 
sure. Ultimately, if sufficiently ex- 
tensible, they would fill the whole 
space, the thinner walled, 6, oceupy- 
ing most of it, If then the stop-cock 
be closed, things will remain in equi- 
io. 118 Diagram fue librium, each bag striving to collapse 
Bting the induenoootas and go exerting a pull on the other, 
ciroulation of the for if Oshrinkscmust expand and wice 
versa. If ¢ suddenly shrink, as the 
heart does in its systole, } will dilate; but as soon as the 
systole of ¢ ceases, } will shrink again and pull ¢ out to 
its previous size. In the same way, after the cardiac sys- 
tole, when the heart-walls relax, the lungs pull them out 
again and dilate the organ. The contracting heart thus 
expends some of its work in overcoming the elasticity of the 
lungs, which opposes. their expansion to fill the space left 
by the smaller heart; but during the diastole of the heart 
this work is utilized to pull out its walls again, and draw 
blood into it. Since the normal heart has muscular power, 
and to spare, for its systole, this arrangement, by which 
some of the work then spent is stored away to assist the 
diastole, which cannot be directly performed by cardiac 
muscles, is of service to it on the whole. It is a physio- 
logical though not a mechanical advantage; no work power 
is gained, but what there is, is better distributed. 








INFLUENCE OF RESPIRATION ON LYMPH-PLOW. 371 


Influence of the Respiration on the Lymph-Flow. 
Durmg inspiration, when intra-thoracie pressure is lowered, 
lymph is pressed into the thoracic duct from the abdomi- 
nal lymphatics. In expiration, when thoracic pressure rises 
again, the extra lymph cannot flow back on account of the 
valves in the lymphatic vessels, and i+ ‘s consequently 
driven on to the cervical ending of the thoracic det. The 
breathing movements thus pump the lymph on. 





CHAPTER XXV. 


THE CHEMISTRY OF RESPIRATION, 


Nature of the Problems. The study of the respira~ 
tory process from 4 chemical standpoint has for its object 
to discover, first, what are, in kind and extent, the inter- 
changes between the air in the lungs and the blood in pul- 
monary capillaries; and, in the second place, the nature 
and amount of the corresponding gaseous changes between 
the various living tissues and the blood in the systemic 
capillaries, These processes are the reverse of one another 
and in the long run balance, the blood losing as much car- 
bon dioxide gas in the pulmonary circulation as it gains in 
the systemic, and gaining as much oxygen in the former 
as it loses in the latter. ‘lo thoroughly comprehend the 
matter it is, moreover, necessary to know the physical and 
chemical conditions of these gases in the lungs, In the 
blood, and in the tissues generally; for only so can we 
understand how it is that in different localities of the Body 
such exactly contrary processes occur. So far as the prob- 
lems connected with the external respiration are concerned 
our knowledge is tolerably complete; but as regards the 
internal respiration, taking place all through the Body, 
much has yet to be learnt; for example, we know that a 
musele at work gives more carbon dioxide to the blood than 
one at rest and takes more oxygen from it, but exactly how 
much of the one it gives and of the other it takes is only 
known approximately; as are also the conditions under 
which this greater interchange during the activity of the 
muscular tissue is effected: and concerning nearly all the 
other tissues we know even less than about muscle, In fact, 
as regards the Body as a whole, it is comparatively easy tg 





CHANGES PRODUCED IN AIR ONCE BREATHED. 373 


find how great its gaseous interchanges with the air are 
during work and rest, waking and sleeping, while fasting 
or digesting, and so on; but when it comes to be decided 
what organs are concerned in each case in producing the 
greater or less exchange, and how much of the whole is due 
to each of them, the question is one far more difficult to 
settle and still very far from completely answered. 

‘The Changes produced in Air by being once Breathed. 
These are fourfold—changes in its temperature, in its 
moisture, in its chemical composition, and its volume. 

The air taken into the lungs is nearly always cooler than 
that expired, which has a temperature of about 36° 0. 
(97° F.). The temperature of a room is usually about 21° 0. 
(70°F). The warmer the inspired air the leas, of course, the 
heat which ig lost to the Body in the breathing process; its 
average amount is calculated as abont equal to 3.5 calories 
in twenty-four hours; a calorie (see Physics) being as mach 
heat as will raise the temperature of one kilogram (2.2 Ibs) 
of water one degree centigrade (1.8° #,), 

The inspired air always contains more or less water vapor, 
but is rarely saturated; that is, rarely contains so much but 
it can take up more without showing it as mist; the warmer 
air is, the more water vapor it requires to suturate it. The 
expired air is nearly saturated for the temperature at which 
it loaves the Body, as ig readily shown by the water deposited 
when it is slightly cooled, as when a mirror is breathed 
upon; or by the clouds seen issuing from the nostrils on a 
frosty day, these being due to the fact that the air, as soon 
as it is cooled, cannot hold all the water vapor which it took 
up when warmed in the Body. Air, therefore,when breathed 
once, gains water vapor and carries it off from the lange; 
the actual amount being subject to variation with the tem- 
perature and saturation of the inspired air: the cooler and 
drier this is, the more water will it gain when breathed. 
On un average the amount thus carried off in twenty-four 
hours is about 255 grams (9 ounces). To evaporate this 
water in the lungs an amount of heat is required, which 
disappears for this purpose in the Body, to appear again 
outside it when the water vapor condenses (see Physics), 





ive 3 THE HUMAN BODY. 


‘The amount of heat taken uff in this way during the day is 
about 7.2 calories, The total daily loss of heat from the 
Body through the lungs is therefore 10.7 calories, 3.5 in 
warming the inspired air and 7.2 in evaporating water. 

‘The most important changes brought about in the 
breathed air are those in its chemical composition. Pure 
air when completely dried consist in 100 parts of— 


By Volume, By Weight. 
20.8 23 
7 


Ordinary atmospheric air contains in addition 4 volumes 
of carbon dioxide in 10,000, or 0.04 in 100, aquantity which, 
for practical purposes, may be neglected. When breathed 
once, such air gains rather more than 4 volumes in 100 of 
carbon dioxide, and loses rather more than 5 of oxygen. 
More accurately, 100 volumes of expired air when dried con- 


154 


‘The expired air also contains volatile organic substances 
in quantities too minute for chemical analysis, bat readily 
detected by the nose upon coming into a close room in 
which a number of persons have been collected. 

Since 10,800 liters (346 cubic feet) of air are breathed in 
twenty-four hours and lose 5.4 per cent of oxygen, the 
total quantity of this gas taken up in the lungs daily is 
10,800 x 5.4% 100 = 583.2 liters (20.4 cubic feet), One 
liter of oxygen me mred at 0°0 (32° FP.) and under a pressure 

ighs 1.43 grams (see Chemistry), 
taken up by the lungs daily is 

ms. Or, using inches and grains as 
cl f oxygen at the above tem~ 
almost exactly 16 grains, so 

the lungs daily weigh 20.4 





VENTILATION. 375 


being 4.3 per cent of the volume of the air breathed- 
daily, is—10,800 x 4.3 + 100 = 464.4 liters (16.25 cubic 

feet) measured at the normal temperature and pressure. 

This volume weighs 910 grams, or 14,105 grains. 

If the expired air be measured as it leaves the Body its 
bulk will be found greater than that of the inspired air, 
since it not only has water yapor added to it, but is 
expanded in consequence of its higher temperature. If, 
however, it be dried and reduced to the same temperature 
as the inspired air its volame will be found diminished, 
since it has lost 5.4 volumes per cent of oxygen and 
gained only 4.3 of carbon dioxide, In round numbers, 100 
volumes of dry inspired air at zero, give 99 volumes of dry 
expired air measured at the same temperature and pres- 
sure. 

Ventilation. Since at every breath some oxygen is taken 
from the air and some carbon dioxide given to it, were the 
atmosphere around a living man not renewed he would, at 
last, be unable to get from the air the oxygen he required; 
he would die of oxygen starvation or be suffocated, as such a 
mode of death is called, as surely, though not quite eo fast, 
as if he were put under the receiver of an air-pump and ull 
the air around him removed. Hence the necessity of ven- 
tilation to supply fresh air in place of that breathed, and 
clearly the amount of fresh air requisite must be deter- 
mined by the number of persons collected in a room; the 
supply which would be ample for one person would be in- 
sufficient for two, Moreover fires, gas, and lamps, all use 
up the oxygen of the air and give carbon dioxide to it, and 
hence calculation must be made for them in arranging for 
the ventilation of a building in which they are to be em- 
ployed. 

In order that air be unwholesome to breathe, it is by 
no moans necessary that it have lost so much of its oxygen 
as to make it difficult for the Body to get what it wants of 
that gas. The evil results of insufficient air-supply are 
rarely, if ever, due to that cause even in the worst ventilated 
rooms for, as we shall see in the next paragraph, the blood 
can take what oxygen it wants from air containing compara 











376 THE HUMAN BODY. 


tively little of that gas. ‘The headache and drowsiness 
which come on from sitting in a badly ventilated room, and 
the want of energy and general ill-health which result from 
permanently living in such, are dependent on a slow poison~ 
ing of the Body by the reabsorption of the things elimi- 
nated from the lungs in previous respirations. What these 
are is not accurately known; they doubtless belong to those 
yolatile bodies mentioned above, as curried off in minute 
quantities in each breath; since observation shows that the 
air becomes injurious long before the amount of carbon 
dioxide in it is sufficient to do any harm. Breathing air 
containing one or two per cent of that gas produced 
by ordinary chemical methods does no particular injury, 
bat breathing air containing one per cent of it produced 
by respiration is decidedly injurious, because of the other 
things sent ont of the lungs at the same time. Carbon 
dioxide itself, at least in any such percentage as is com- 
monly found in a room, is not poisonous, as used to be 
believed, but, since it is tolerably easily estimated in air, 
while the actually injurious substances evolved in breath- 
ing are not, the purity or foulness of the air in a room is 
usually determined by finding the percentage of carbon 
dioxide in it; but it must be borne in mind that to mean 
much this must have been produced by breathing; other- 
wise the amount of it present is no guide to the quantity of 
really important injurious substances present. Of course 
when a great deal of carbon dioxide is present the air is 
irrespirable: as for example sometimes at the bottom of 
wells or brewing-vata. 

Tn one minute as we have seen (p. 366) .5 x 15 = 7.5 
liters (0.254 enbic feet) of airare breathed and vitiated with 
carbon dioxide to the extent of rather more than four per 
cent; this, mixed with three times its yolume of external 
air, would give thirty liters (a little over one eubic foot) 
Vitiated to the extent of one per cent, and such air is no 
longer respirable for any length of time with safety. The 
result of breathing it for an evening is headache and gen- 
eral malaise; of breathing it for weeks or months a lowered 
tone of the whole Body—less power of work, physical dr 





VENTILATION, 


mental, and Tess power of resisting disease; the ill effecta 
may not show themselves at once, and may accordingly be 
overlooked, or considered scientific fancies, by the careless; 
but they are there ready to manifest themselves neverthe- 
less. In order to have air to breathe in a fairly pure 
state every man should have for his own allowance at least 
23,000 liters of space to begin with (about 800 cubic fect) 
and the arrangements for ventilation should, at the very 
least, renew this at the rate of 30 liters (one cubic foot) 
per minute. The nose is, however, the best guide, and it 
ig found that at least five times this supply of fresh air is 
necessary to keep free from any odor the room inhabited by 
one adult, In the more recently constructed hospitals, as 
a result of experience, twice the above minimum cubic space 
is allowed for each bed in a ward, and the replacement of 
the old air at a far more rapid rate, is also provided for. 

Ventilation does not necessarily mean draughts of cold 
air, as is too often supposed. In warming by indirect radia- 
tion it may readily be secured by fixing, in addition to the 
registers from which the new warmed air reaches the room, 
corresponding openings at the opposite side, by which the old 
air may pass off to make room for the fresh, An open fire 
in a room will always keep up a current of air through it, 
and is one of the healthiest, though not the most economi- 
eal, methods of warming an apartment. 

Stoves in a room, unless constantly supplied with fresh air 
from without, dry its air to an unwholesome extent. If no 
appliance for providing this supply exists in a room, it can 
usually be got, without a draught, by fixing a board about 
four inches wide under the lower sash and shutting the 
window down on it. Fresh air then comes in by the open- 
ing between the two sashes and in a current directed 
upwards, which gradually diffuses itself over the room with- 
out being felt as a draught at any one point. In the 
method of heating by direct radiation, the apparatus em- 
ployed provides of itself no means of drawing frosh air into 
a room, as the draught up the chimney of an open fireplace 
or of a stove does; and therefore special inlet and ontlet 
openings are very necessary. Since fow doors and windows, 











378 THE HUMAN BODY. 


fortunately, fit quite tight, fresh air gets even ito closed 
rooms, in tolerable abundance for one or two inhabitants, 
if there be outlets for the air already in them. 

Changes by the Blood in the Lungs. These 
are the exact reverse of those exhibited by the breathed air - 
—what the air gains the biood loses, and vice versa. Con- 
sequently, the blood loses heat, and water, and carbon 
dioxide in the pulmonary capillaries; and gains oxygen. 
These gains and losses are accompanied by a change of color 
from the dark purple which the blood exhibits in the pul- 
monary artery, to the bright scarlet it possesses in the pul- 
monary veins. 

‘The dependence of this color change upon the access of 
fresh air to the lungs while the blood is lowing through them, 
can be readily demonstrated. If a rabbit he rendered 
unconscious by chloroform, and its chest be opened, after a 
pair of bellows has been connected with its windpipe, it is 
seen that, so long as the bellows are worked to keep up 
artificial respiration, the blood in the right side of the heart 
(as scen through the thin auricle) and that in the pulmo- 
nary artery, is durk colored, while that in the pulmonary 
veins and the left auricle is bright red. Let, however, the 
artificial respiration be stopped for a few seconds and, 
consequently, the renewal of the air in the lungs (since an 
animal cannot breathe for itself when its chest is opened), 
and yery soon the blood returns to the left auricle as dark 
as it left the right. In a very short time symptoms of 
suffocation show themselves and the animal dies, unless 
the bellows be again set at work. 

Tho Blood Gases, If fresh blood be rapidly exposed to 
as complete a vacuum as can be obtained it gives off certain 
gases, known as the gases of the blood. These are the same 
in kind, but differ in proportion, in yenons and arterial 
blood; there being more carbon dioxide and less oxygen 
obtainable from the yenous blood going to the lungs by the 
pulmonary artery, than from the arterial blood coming back 
to the heart by the pulmonary veins, The gases given off 
by venous and arterial blood, measured under the normal 

mesure and at the normal temperature (see Physics), 


ai 


THE BLOOD GASES. 879 


amount toabout?2 volumes for every 100 volumes of blood, 
and in the two cases are a3 follows— 


Oxygen. .-... 

Carbon dioxide. 

Nitrogen. ... 
It is important to bear in mind that while arterial blood 
contains some carbon dioxide that can be removed by the 
air-pump, venous blood also contains some oxygen, remova- 
ble in the same way; 80 that the difference between the 
two is only one of degree. When an animal is killed by 
Fiffocation, however, the last trace of oxygen which can be 
yielded up in a vacuum, disappears from the blood before 
the heart ceases to beat. All the blood of such an animal 
is what might be called suffocation blood; and has a far 
darker color than ordinary venous bluod. 

‘The Cause of the Bright Color of Arterial Blood. The 
color of the blood depends on its red corpuscles, since pure 
blood plasma or blood serum is colorless, or at most a very 
faint straw yellow. Hence the color change which the blood 
experiences in circulating through the lungs must be due 
to some change in its red corpuscles. Now, minute solid 
bodies suspended in a liquid reflect more light when they 
are more dense, other things being equal; and the first 
thing that suggests itself as the cause of the change in 
color of the blood is that. its red corpuscles have shrunk in 
the pulmonary circulation, and ao reflect more light and 
give the blood a brighter look. This idea gains some 
support from the fact that, as seen under the microscope, 
the red blood corpuscles of some animals, as the frog, do 
expand somewhat when exposed to carbon dioxide gas and 
shrink up alittle in oxygen. But that this is not the chief 
cause of the color change is readily proved. By diluting 
blood with water the coloring matter of the red corpuscles 
can be made to pass out of them and go into solution in the 
plasma (p. 46) and it is found that such a solution, in which 
there can be no question as to the reflecting powers of 
colored solid bodies suspended in it, is brighter red when 
supplied with oxygen thau when deprived of that gas. 








880 THE HUMAN BODY. 


This suggests that the coloring matter or hemoglobin of 
the red corpuscles combines with oxygen to form a scarlet 
compound, and when deprived of that gas has a darker and 
more purple color; and further experiments confirm this. 
Hemoglobin combined with oxygen is known as oryhamo- 
globin and it is on its predominance that the color of 
arterial blood depends. Hemoglobin uncombined with oxy- 
gen is reduced hemoglobin; it predominates in venous blood, 
and is alone found in the blood of suffocated mammal. 

Tho Laws Governing the Absorption of Gases by a 

In order to understand the condition of the gases 
in the blood liquid it is necessary to recall the general laws 
in accordance with which liquids absorb gases. They are 
as follows:— 

1. A given volume of a liquid at a definite temperature 
if it absorbs any of a gas to which it is exposed, and yet does 
not combine chemically with it, takes up a definite volume 
of the gas. If the gas be compressed the liquid will still, 
at the same temperature, take up the same volume as before, 
but now it takes up a greater weight; and a weight exactly 
as much greater as the pressure is greater, since one volume 
of a gas under any pressure contains exactly twice as much 
of the gas by weight as the same volume under half the 
pressure, and soon. A liter ora quart of water, for example, 
exposed to the air will dissolve a certain amount of oxygen. 
If the air (and therefore the oxygen in it) be compressed to 
one fourth its bulk then the water will dissolve exactly the 
same Yolume of oxygen as before, but this volume of the 
compressed gas will contain exactly four times as much 
oxygen as did the same volume of the gus under the origi- 
nal pressure; and if now the pressure be again diminished 
the oxygen will be given off exactly in proportion as its 
pressure on the surface of the water decreases. Finally, 
when a complete vacnum is formed above the surface of the 
water it will be found that the latter has given off all its 
dissolved oxygen. This law, that the quantity of a gas dis- 
solved by a liquid varies directly as the pressure of that 





on the surface of the liquid is known as Dalton’s law (see 
Phaynxics). 





THE ABSORPTION OF GASES BY LIQUIDS 481 


2. The amount of a gas dissolved by aliquid depends, not 
on the total pressure exerted by all the gases pressing on 
its surface, but on the fraction of the total pressure which 
us exerted by the particular gas in question. For example, 
the total atmospheric pressure is equal to that of a column 
of mercury 760 mm. (30 inches) high. But 100 volumes 
‘of air contain approximately 80 volumes of nitrogen and 
20 of oxygen: therefore } of the total pressure is due to 
oxygen and ¢ to nitrogen: and the amount of oxygen 
absorbed by water is just the same as if all the nitrogen 
were removed from the air and its total pressure there- 
fore reduced to 4 of 760 mm. (30 inches) of mercury; that 
is to 152 mm, (6 inches) of mercury pressure, It is only 
the fraction of the total preasure exerted by the oxygen 
itself which affects the quantity absorbed by water at any 
given temperature, So, too, of all the atmospheric pressure 
+ is due to nitrogen, and all the oxygen might be removed 
from the air without affecting the quantity of nitrogen 
which would be absorbed from it by a given volume of 
water. ‘he atmosphoric pressure would then be ¢ of 760 
mm. of mercury, or 608 mm. (24 inches), but it would all 
be due to nitrogen gas—and be exactly equal to the fraction 
of the total pressure due to that gas before the oxygen was 
vemoyed from the air. Whon several gases are mixed to- 
gethor the fraction of the total pressure exerted by each 
one is known as the partial pressure of that gas; and it is 
this partial pressure which determines the amount of each 
individual gas dissolved by aliquid. If a liquid exposed 
to the air for some time had taken up all the oxygen and 
nitrogen it could at the partial pressures of those gases in 
the air, and were then put in an atmosphere in which the 
oxygen had all been replaced by nitrogen, it would now 
give off all its oxygen since, although the total gaseous 
pressure on it was the same, no part of it was any longer 
due to oxygen; aud at the same time it would take up 
more nitrogen, since the whole gaseous pressure on its sur- 
face was now due to that gus while before only ¢ of the 
total wasexerted by it. If, on the contrary, the liquid were 
exposed to pure hydrogen under a pressure of one attmos- 





THE HUMAN BODY, 
a. 


here it would give off ull its previously dissolved oxygen 
mT nitrogen, since none of the pressure on its surface would 
now be due to those guses; and would take up as much 
hydrogen as corresponded to a pressureof that gas equal to 
760 mm, of mereury (30 inches). 

3. A liquid may be such as to combine chemically with 
agas. ‘Then the amount of the gas absorbed is indepen- 
dent of the partial pressure of the gas on the surface of the 
liquid. The quantity absorbed will depend upon how much 
the liquid can combine with. ° Or, a liquid may partly be 
composed of things which simply dissolve a gas and partly 
of things which chemically combine with it. Then the 
amount of the gas taken up under a given partial pressure 
will depend on two things; a certain portion, that merely 
dissolved, will vary with the pressure of the gas in question; 
bunt another portion, that chemically combined, will remain 
the same under different pressures. The amount of this 
second portion depends only on the amount of the sub- 
stance in the liquid which ean chemically combine with it, 
and is totally independent of the partial pressure of the 


gas, 

4. Bodies are known which chemically combine with 
certain gases when the partial pressure of these is consider~ 
able; but the compounds thus formed are broken up, and 
the gas liberated, when its partial pressure on the surface 
of the liquid falls below a certain limit, 

5. A membrane, moistened by a liquid in which a gas is 
soluble, does not essentially alter the laws of absorption, by 
a liquid on one side of it, of a gas present on its other side, 
whether the absorption be due to mere solution or to 


en by the Blood. Applying 
facts stated in the preceding 
ind that the blood contains (1) 
n, and (2) hamoglobin, 

partial pressures of 


the same thing, fresh 





ABSORPTION OF OXYGEN BY THE BLOOD. 383 


much water, that is about 3 volumes of the gas for every 
100 of the liquid. This quantity obeys Dalton’s law. 

If instead of blood serum fresh whipped blood be em- 
ployed, the quantity of oxygen taken up is much greater; 
this extra quantity must therefore be taken up by the red 
corpuscles (in possessing which whipped blood alone differs 
from blood seram) and it does not obey Dalton’s law. It 
the partial pressure of oxygen on the surface of the 
whipped blood be doubled, only as much more oxygen will 
be taken up as corresponds to that dissolved in the plasma; 
and if the partial pressure of oxygen on its surface be re- 
duced to one half only a very small amount of oxygen (+ 
of that dissolved by the seram) will be given off. All the 
much larger quantity taken up by the red corpuscles will 
be unaffected and must therefore be chemically combined 
with something in them. Since 90 per cent of their dry 
weight is made up by hemoglobin, and this body when pre- 
pared pure is found capable of combining with oxygen, there 
isno doubt that it isthe hwmoglobin in the circulating blood 
which carries around nearly all the oxygen found in it. 
The red corpuscles are s0 many little packages in which 
oxygen is stowed away. 

The compound formed between oxygen and hemoglobin 
is, however, a very feeble one; the two easily separate, and 
always do so when the oxygen pressure in the liquid or gas 
to which the oxyhemoglobin is exposed falls below 25 mil- 
limeters of mereury. Hence, in an air-pump, the blood only 
gives off some of its small portion of merely dissolved oxy- 
gen, until the pressure falls to about } of an atmosphere, 
that is to 742 = 125 mm. (5 inches) of mercury, of which 
total pressure one fifth (25 millimeters or 1 inch) is due to 
the oxygen present. As soon as this limit is reached the 
hawmoglobin gives up its oxygen. 

Consequences of the Peculiar Way in which the 
‘Oxygen of the Blood is Held. The first, and most im- 
portant, is that the blood can take up far more oxygen in 
the lungs than would otherwise be possible. Since blood 
serum oxposed to pure oxygen takes up only 3 volumes for 
100, blood exposed to the air would take up } only of that 








384 THE HUMAN BODY, 


amount at ordinary temperatures, and still less at the tem~ 
perature of the Body, were it not for its hemoglobin. In 
the lungs even less would be taken up, since the air in the 
air-cells of those organs is poorer in oxygen than the 
external air; and consequently the partial pressure of 
that gas in it is lower, The tidal air taken in at each 
breath serves merely to renew directly the air in the big 
bronchi; the deeper one examined the pulmgnary air the 
less oxygen and more carbon dioxide would be found, 
till, in the layers farthest from the exterior and only re~ 
newed by diffusion with the air of the large bronchi, it is 
estimated that the oxygen only exists in such quantity that 
its partial pressure is equal to 130 millimeters of mercury, 
instead of 152 asin ordinary air. In the second place, on 
account of the way in which hemoglobin combines with 
oxygen, the quantity of that gas taken up by the blood is 
independent of such variations of its partial pressure in the 
atmosphere as we are subjected to in daily life, At the top 
of a high mountain, for example, the atmospheric pressure 
is greatly diminishod, but still we can breathe freely and got 
all the oxygen we want. So long as the partial pressure of 
that gas remains above 25 millimeters (1 inch) of mercury, 
the amount of it taken up by the blood will depend on how 
much hemoglobin there is in that liquid and not on how 
much oxygen there is in the air, So, too, breathing pure 
oxygen under a pressure of one atmosphere, or air com~ 
pressed to 4 or ¢ its bulk, does not increase the quantity of 
that gas taken up by the blood, apart from the very small 
extra quantity which would be dissolved by the plasma, 
All the widespread statements found as to the exhilaration” 
and excitement caused by breathing pure oxygen are, a8 a 
matter of fact, erroneous, being founded on early experi- 
ments made with impure gas, and corrected by many com- 
petent observers since. 

The General Oxygen Interchanges inthe Blood. Wo 
may now try to depict what happens to the blood oxygen 
in a complete circulation. Suppose we have a quantity of 
arterial blood in the aorta, This, fresh from the lungs, will 
have its hemoglobin almost fully combined with oxygen 











4 


THE BLOOD GASES, 885 


aud in the state of oxyhwmoglobin. In the blood plasma 
some more oxygen will be dissolyed and so. much as answers 
to a pressure of that gus equal to 130 mm. (5.2 inches) of 
mercury, which is the partial pressive of oxygen in the 
pulmonary air-cells. This tension of the gas in the plasma 
will be more than sufficient to keep the hemoglobin from 
giving off its oxygen. Suppose the blood now enters the 
capillaries of a muscle. In the liquid moistening this organ 
the oxygen tension is almost nil, since the tissue elements 
are steadily taking the gas up from the lymph around them. 
Consequently, through the capillary walls, the plasma will 
give off oxygen until the tension of that gus im it falls below 
25 millimeters of mercury. Immediately some of the oxy- 
hwmoglobin is decomposed, and the oxygen liberated is dis- 
solved in the plasma, and from there again passed on to the 
lymph outside; and so the tension in the plasma is once 
more lowered and more oxyhwmoglobin decomposed. ‘This 
goes on 80 long as the blood is in the capillaries of the 
muscle, or at any rate so long as the muscular fibres keep 
on taking oxygen from the lymph bathing them; if they 
cease to do so of course the tension of that gas in the lymph 
will 800m come to equal that in the plasma: the latter will 
therefore cease to yield oxygen to the former; and so main- 
tain its tension (by the oxygen received from the last de- 
composed oxyhwmoglobin) at a point which will preven’ 
the liberation of any more oxygen from such red corpuscles 
as have not yet given all theirs up. The blood will now go 
on as onlinary venous blood into the veins of the muscle 
and 80 buck to the lungs, It will consiat of (1) plasma 
with oxygen dissolved in it at a tension of about 25 milli- 
meters (1 inch)*of mercury. (2) A number of red cor- 
puscles containing reduced hemoglobin. (3) A number of 
red corpuscles containing oxyhwmoglobin. Or perhaps all 
of the red corpuscles will contain some redaced and some 
oxidized hemoglobin. ‘The relative paoportion of reduced 
and unreduced hemoglobin will depend on how active the 
muscle was; if it worked while the blood flowed through it 
it will have used up more oxygen, and the blood leaving it 
will conseqnoutly be more venous, than if it rested. ‘This’ 





THE HUMAN BOpY. 


— a ee 
monsry capillanes Here, the partis] preaeare of 

ju thee ir calle being 130 anon. (0-2 inchoe}-and flee 
blood plasms mach lex, oxygen will be taken up by the 
latter, and the tenson of that gas in the plasma tend to be 
raised above the limit st wlich hemeglobin combines with 
it. Hence, as fast as the plasma gets oxygen these red Gor~ 
puscles which contain any reduced hemoglobin rob it, and 
#0 its oxygen tension ix kept down below that in the air- 
cells until all the hemoglobin is suticfed. Then the 
exygen tension of the plasms rises to that of the gas in the 
sir-cells; no more oxygen is sheorbed, and the bleod retarns 
to the left auricle of the beart in the same condition, 
far as oxygen is concerned, as when we commenced to fol- 
low it. 


laws apply to this as to the blood oxygen. The gas 
partly merely dissolved and partly in s loose chemical cam~ 
bination much like that of oxygen with hemoglobim, but 
the body with which it combines in this way exists in the 
plasma snd not in the red corpuscles; what it may be ia. 
not certainly known. Besides this, some more carbon 
dioxide is stably combined and ix only given off on the 
addition of a stronger acid. The partial presure of carbon 
dioxide in the pulmonary air-cells is about 40mm. (1.6 
inches) of mercury. Therefore the tension of that gas in 
the pulmonary capillaries must be more than this. On 
the other hand its tension in arterial blood must be less 
than that in the lymph around the tissues; otherwise it 
could not enter the blood in the systemic circulation, which 
it does, as proved by the fact that 100 vols ef venous blood 





INTERNAL RESPIRATION. 887 


in a given time bears no constant ratio to the amount of 
oxygen taken up by it simultaneously. his is certainly 
true of muscle, for experiment shows that muscular work, 
while it continues, leads to an elimination of carbon dioxide 
containing more oxygen than the total oxygen taken up 
from the lungs in the same time. The balance is of course 
made up in subsequent periods of rest, when more free 
oxygen is taken up than is eliminated in combination 
during the same time. Moreover, a frog’s muscle excised 
from the body and put in an atmosphere containing no 
oxygen and made there to coutract, will evolve with each 
contraction considerable quantities of carbon dioxide— 
although from the conditions of the experiment it can 
receive from outside no uncombined oxygen, and other 
experiments show that it contains none, Hence the living 
muscular fibre must contain a substance which is decom- 
posed during activity and yields carbon dioxide as one pro- 
duct of decomposition; and this quite independent of any 
simultanoons direct oxidation. 

2, What is true of muscle is probably true of most of 
the tissucs, During rest they take up oxygen and fix it 
in the form of complex compounds, bodies which, like gun- 
powder, are readily decomposed into simpler, and in such 
decompositions liberate energy which is nsed by the work- 

me. One product of the decomposition is the 

ighly oxidized carbon dioxide, ond is eliminated; 

other | products are less oxidized, and possibly are not elimi- 

nated but built up again, with fresh oxygen taken from the 

blood and fresh carbon from the food, into the decomposa- 
ble substanc 

8, During the day a man gives off from his lungs more 

in carbon dioxide, than he takes up by the same 
he air. During the night the reverse is the 
ever, has nothing to do with the alternating 

and darkness, as it has in the case of a 

in the light evolves more oxygen than 

in the dark the contrary. It depends, 

fact that during the day more muscular effort 

mn at night, and the meals are then taken 





388 THE HUMAN BODY. 





and digested. The activity of the muscles and the digestive 
glands is dependent on processes which give rise to a large 
production of carbon dioxide and, daring the night, when 
both are at rest, more oxygen is taken up than is contained 
in the carbon dioxide eliminated. If a man works and 
takes his meals at night, and sleeps in the day, the usual 
ratios of his gaseous exchanges with the exteriorare entirely 
reversed. 

4, The amount of work that a man’s organs do, is not 
dependent on the amount of oxygen supplied to them, but 
the amount of oxygen used by him depends on how much 
he uses his organs. The quantity of oxygen supplied must 
of course always be, at least, that required to prevent saffoca- 
tion; but an excess above this limit will not make the tissnes 
work. Just as a man must haye a certain amount of food 
to keep him alive, so he must have a certain amount of 
oxygen; but as extra food will not make his tissues or him 
(who is physiologically the sum of all his tissues) work, 
apart from some stimulus to exertion, so it is with oxygen. 
Highly arterialized blood, or an abnormal amount of blood, 
flowing through an organ will not arouse it to activity; 
the working organ, muscle (p. 257) or gland (p. 269), for ex- 
ample, usually gets more blood to supply its extra needs— 
just as a healthy man who works will have a better appo- 
tite than an idle one; but as taking more food by an idle 
man will not of itself make him more energetic, so neither 
will sending more arterial blood through an organ excite 
it to activity. 

5. The preceding statement is confirmed by experiments 
which show that an animal uses no more oxygen in an hour 
when made to breathe that gas in a pure stute, than when 
allowed to breathe ordinary air. In other words, the 
amount of oxygen an animal uses (provided it geta the 
minimum necessary for health) is dependent only on how 
much it uses its tissues. These (the rest in most cases sub- 
ject to a certain amount of control from the neryous) de- 
termine their own activity, and this, in turn, how much 
oxygen shall be used in the systemic circulation and re- 


INTERNAL RESPIRATION. 389 


stored in the pulmonary. In other words, the physiological « 
work of an animal, which in turn is largely dependent upon 

how external forces act upon it, determines how much 

oxygen it uses daily; and not the supply of oxygen how 

much its tissue activity shall be, unless the supply sinks 

below the starvation limit. 








CHAPTER XXVI. 


THE NERVOUS FACTORS OF THE RESPIRA- 
TORY MECHANISM. ASPHYXTA. 


The Respiratory Centre. ‘he respiratory movements 
are to a certain extent under the control of the will; we 
can breathe faster or slower, shallower or more deeply, as 
we wish, and can also “ hold the breath” for some time—but 
the voluntary control thus exerted is limited in extent; 
no one can commit suicide by holding his breath, In 
ordinary quiet breathing the movements are quite inyolun- 
tary; they go on perfectly without the least attention on 
our part, and, not only in sleep, but during the unconscions- 
ness of fainting or of an apoplectic fit. The natural breath- 
ing movements are therefore either reflex or automatic. 

The muscles concerned in producing the changes in the 
chest which lead to the entry or exit of air are of the 
ordinary striped kind; and these, as we have seen, only con- 
tract in the Body under the influence of the nerves going 
to them; the nerves of the diaphragm are the two phrenic 
nerves (p. 161), one for each side of it; the external inter- 
costal muscles are supplied by certain branches of the dor- 
sal spinal nerves, called the intercostal nerves. If the 
phrenic nerves be cut the diaphragm coases its contractions, 
and a similar paralysis of the external intercostals follows 
section of the intercostal nerves. 

Since the inspiratory muscles only act when stimulated, 
by nervous impulzes reaching them, we have next to seek 
where these impulses originate; and experiment shows that 
it is in the meduila oblongata. All the brain of a cat ora 
rabbit in front of the medulla can be removed, and it will 
still goon breathing; and children are sometimes born with 


ai 


THE RESPIRATORY CENTRE, 891 


the medulla oblongata only, the rest of the brain being un- 

_ developed, and yet they breathe perfectly well. If, on the 
other hand, the spinal cord be divided immediately below 
the medulla of an animal all breathing movements of 
the chest cease at once. We conclude, therefore, that the 
nervous impulses calling forth contractions of the respira- 
tory muscles aris¢é in the medulla oblongata, and travel 
down the spinal cord and thence out along the phrenic and 
intercostal nerves. This is confirmed by the fact that if 
the spinal cord be cut across below the origin of the fourth 
pair of cervical spinal nerves (from which the phrenics 
mainly arise) but above the first dorsal spinal nerves, 
the respiratory movements of the diaphragm continue but 
those of the intercostal muscles cease; this phenomenon 
has sometimes been observed in men stabbed in the back, so 
as to divide the spinal cord in the region indicated, Finally, 
that the nervous impulses exciting the inspiratory muscles 
originate in the medulla, is proved by the fact that if a 
emall portion of that organ, the eo-called vital point, be 
destroyed, all the respiratory movements coase at once and 
forever, although all the rest of the brain and spinal cord 
may be left uninjured. This partof the medulla is known 
as the respiratory contre. 

In the above statements, for the anke of simplicity, atten- 
tion has been chiefly confined to the diaphragm and the 
intercostal muscles; but-what is said of them is true of the 
respiratory innervation of all other breathing muscles, 
whether expiratory or inspiratory, normal or extraordinary; 
in all cases the impulse giving rise to a respiratory move- 
ment starts from the centre placed in the medulla oblon- 
gata. 

Is the Respiratory Contre Roflex? Since this centre 
goes on working independently of the will we have next to 
inquire is it a reflex centre or not; are the efferent dis- 
charges it sends along the respiratory nerves due to afferent 
impulses reaching it by centripetal nerve-fibres; or does it 
originate efferent nervous impulses independently of excita- 
tion through afferent nerves? 

We know, in the first place, that the respiratory centre is: 








392 THE HUMAN BODY, 


largely under reflex control; a dash of cold wate: on the 
ekin, the irritation of the nasal mucous membrane by 
snuff, or of the larynx by a foreign body, will each cause a 
modification in the respiratory movements—a long indrawn 
breath, a sneeze, or a cough. But, although thus subject 
to influences reaching it by afferent nerves, the respiratory 
centre seems essentially independent of such. In many 
animals, as rabbits, (and in some men,) marked breathing 
movements take place in the nostrils, which dilate during 
inspiration; and when the spinal cord of a rabbit is eut close 
to the medulla, thus cutting off all afferent nervous im- 
pulses to the respiratory centre except such as may reach 
it through cranial nerves, the respiratory movements of the 
nostrils still continue until death. The movements of the 
ribs and diaphragm of course cease, and so the animal 
dies very soon unless artificial respiration be maintained. 
Moreover, if after cutting the spinal cord as above described, 
all afferent cranial nerves be divided, so as to cut off the 


respiratory centre from all possible afferent nervous im- 
pulses, the regular breathing movements of the nostrils 
continue. It is, therefore, obvious that the activity of the 
respiratory contre, however much it may be capable of 
modification through sensory nerves, is essentially inde- 
pendent of them; in other words the normal respiratory 
movements are not refle: 


ves the respiratory centre 

is the greater or le: osity of the blood flowing through 
ite is bh o in oxygen and comparatively 
in ide the re spiratory centre acts but feebly, 

ah ‘If, on the other hand, this 

‘tory movements are more 

extraordinary muscles of 


aération of the blood, is 
eathing iseupnoa. Ifthe 
up forced ie 





STIMULATION OF THE RESPIRATORY CENTRE. 393 


centre, and the animal therefore remains without breathing 
at all for some time; this condition is apnwa, though phy- 
sicians by the word apnaa commonly mean merely extreme 
dyspnea. If an animal be made apneic and the artificial 
respiration stopped, its blood, during the cessation of the 
respiratory movements, gradually losing oxygen and recety- 
ing carbon dioxide, passes into the state of ordinary blood 
and again stimulates the respiratory centre, and the breath- 
ing movements then recommence. 

How it is that highly venous blood causes great excita- 
tion of the respiratory centre, and highly arterial cessation 
of its activity, isnot certainly known; but we may make the 
following provisional hypothesis. The chemical changes 
occurring in the respiratory centre give rise to a substance 
or substances which stimulate its nerve-cells, When the 
blood is richly supplied with oxygen this substance is oxi- 
dized and removed as fast as it is formed, and so the centre 
is not excited. When the blood, on the other hand, is un- 
usually poor in oxygen, this stimulating body accumulates 
and the respiratory discharges become more powerful. 
Under normal circumstances the blood oxygen is not kept 
quite up to the point of entirely removing this exciting 
substance, and the centre is stimulated so far as to pro 
duce the natural breathing movements but not the more 
forced ones of dyspnaa. ‘That the stimulating cause, what- 
ever it is, acts upon the respiratory centre and not upon the 
various organs of the Body and through their sensory 
nerves, in turn, upon the medulla, is proved not only by the 
facts above cited showing that the respiratory centre con- 
tinues to act when all afferent nerves are cut off from it, 
but also by experiments which show that the circulation of 

through the body of an animal, while at the 

its respiratory centre is supplied with arterial 

s not produce dyspnma; while sending venous 
the medulla and arterial to all the rest of the Body 


Rhythmic? Every 
tion and a pause; and then follows the inspiration of the 








38 THE HUMAN BODY. 


Bextact. In natural quiet bresthing there is no execntial 
difference between the expiration and the pause. The in- 
spiration is the only active part (p. 363); the expiration and 
the pause sre dependent on muscular inactivity and, there 
fore, on the cessation of the discharge of nervous impulses 
from the respiratory centre. Bat then, we may ask, if in 
secordance with the hypothesis made in the last paragraph, 
the respirstory centre is constantly being excited, why is it 
not always discharging? why does it only snd out nervous 
impulses at intervals? This question, which is easentially the 
same as that why the heart beats rhythmically, belongs to 
the higher regions of Physiology and can only st present be 
hypothetically answered. Let us consider, for s moment, 
ordinary mechanical circumstances under which s steady 
supply is turned inte an intermittent discharge. Suppose 
a tube closed water-tight below by a hinged plate, which is 
keptehut bya «pring, If asteady stream of water is poured 
into the tube from above, the water will rise until ite weight 
is able to overcome the pressure of the spring, and the 
plate will then be forted down and some water flow out, 
The spring will then press the plate up again, and the water 
accumulate until its weight again forces open the bottom of 
the tube, and there is another outrush; and so om By 
opposing a certain resistance to the exit we could this 
turn a steady inflow into s rhythmic outilow. Or, take the 
case of a tube with one end immersed in water and s steady 
stream of air sent into its otherend. The air will emergo 
from the immersed end, not in a steady current, but ins 
series of bubbles. Its pressure in the tube must rise 
until it is able to overcome the cohesive force of the water, 
and then a bubble bursts forth; after this the sirhas again 
to get up the requisite pressure in the tube before another 
| bubble is ejected; and so the continuous supply is trans 
| formed into an intermittent delivery. Physiologists sup. 
} pose something of the same kind to occurin the respire 
j tory centre. Its nerve-cells are always, under usnal 
| circumstances, being excited; but, to discharge a nervous 
| impulse along the efferent respiratory nerves, they have to 
overcome a certain resistance. The nervous impulses have 


il 














CAUSE OF THE RESPIRATORY RHYTHM, 395 


to accumulate, or “gain a head,” before they travel out 
from the centre, and, after their discharge, time is required 
to attain once more the necessary level of irruption before a 
fresh innervation is sent to the muscles. This method of 
accounting for the respiratory rhythm is known as the 
“resistance theory.” 1f not altogether satisfactory it is at 
least far preferable to the older mode of considering the 
question solved by assuming a rhythmic character or prop- 
erty of the respiratory centre. It gives a definite hypothe- 
sis, which accords with what is known of general natural 
laws outside of the Body, and the truth or falsity of which 
can be tested by experiment: and so serves very well to 
show how scientific differs from pre-scientific, or medimval, 
physiology. The latter was content with observing things 
in the Body and considered it explained a phenomenon 
when it gave it yame. Now we call a phenomenon ex- 
plained, when we have found to what general category 
of natural laws it can be reduced as a special example; 
and this reducing a special case to a particular manifesta- 
tion of some one or more general properties of matter 
already known is, of course, all that we ever mean whin we 
say we explain anything. We explain the fall of an apple 
and the rise of the tides by referring them to tho class of 
general results of the Law of Gravitation; but the why of 
the law of gravitation we do not know at all; it is merely a 
fact which we have found out. So with regard to Physi- 
ology; we are working scientifically when we try to reduce 
the activities of the living Body to special instances of 
mechanical, physical, or chemical laws otherwise known to 
us, and unscientifically when we lose sight of that aim, 
Certain vital phenomena, as those of blood-pressure, we can 
thus explain, as much as we can explain anything; others, as 
the rhythm of the respiratory movements, we can provision- 
ally explain, although not yet certain that our explann- 
tion is the right one; and still others, as the phenomena of 
consciousness, we cannot explain at all, and possibly never 
will, by referring them to general properties of matter, 
since they may be properties only of that particular kind of 











396 THE HUMAN BODY. 


matter ealled protoplasm, and perhaps only of some yarie- 
ties of it. 

The Relation of the Pneumogastric Nerves to the Res- 
piratory Centre. We haye next to consider if any pheno- 
mena presented by the living Body give support to the 
resistance theory of the respiratory rhythm. A very im- 





portant collateral prop to it is given by the relation of the — 


phenmogastric nerves to the rate and force of the respira~ 
torymoyements. ‘These nerves give branches to the larynx, 
the windpipe, and the lungs, in addition to numerous other 
parts, and might therefore be suspected to have something 
to do with breathing. That they are not concerned in in- 
fluencing the respiratory muscles directly is shown by the 
fact that all of these muscles (except certain small ones in 
the larynx) contract as usual in breathing after both 
pneumogastrie nerves have been divided. Still, the section 
of both nerves has a considerable influence on the respira- 
tory movements; they become slower and deeper. We may 
understand this by supposing that the resistance to the dis- 
charges of the respiratory centre is liable to variation. Tt 
may be increased, and then the discharges will be fewer and 
larger; or diminished, and then they will be more frequent 
bat each one less powerful. If the spring, in the MMustne 
tion used in the preceding paragraph, be made stronger, 
while the inflow of water to the tube remaine the same, the 
outflows will be less frequent bat each one greater; and vice 
versa. The effect of section of the pneumogastric trank 
may, therefore, be explained if we suppose that, normally, it 
carries up, from its lung branches, nervous impulses whicl: 
diminish the resistance to the discharges of the respiratory 
centre; when the nerves are cut these helping impulses are 
lost to the centre, and its impulses must gather more head 
before they break out, but will be greater when they do. 
This view is confirmed by the fact that stimulation of the 
central ends of the divided pneumogastrics, if weak, brings 
back the respirations to their normal rate and force; if 
stronger makes them more rapid and shallower; and when 
strongor still, abolishes the respiratory rhythm altogether, 
with the inspiratory muscles in a steady state of feeble con- 


THE EXPIRATORY CENTRE. 3907 


traction. That is to say, the resistance to the discharges of 
the centre being entirely taken away (which is equivalent 
to the total removal of the spring in our example), the cen- 
tre sends out uninterrupted and non-rhythmie stimuli to 
the inspiratory muscles. 

‘The pneumogastric nerve gives two branches to the larynx; 
known respectively as the superior and inferior (recurrent) 
Jeryngeal nerves; the action of these on the respiratory 
centre is opposite to that of the fibres from the Jungs 
coming up in the main ymeumogastric trunk, If the 
superior laryngeal branch be divided and its central end 
stimulated, the respirations become less frequent but each 
one more powerful; hence this nerve is supposed to increase 
the resistance to the discharges of the respiratory centre. 
‘The same, but to a less degree, is true of the inferior laryn- 
geal branch. 

The Expiratory Centre. Hitherto we have considered 
breathing as due to the rhythmically alternating activity 
and rest of an inspiratory contre—and such is the case in 
normsl quiet breathing, in which the expirations are pus- 
sive. But in dyspnea expiration is a muscular act, and 
so there must be a section of the respiratory centre control 

ng the expiratory muscles. ‘This part of the respiratory 
however, is less irritable than the inspiratory part, 

i nee when the blood is in a normal state of aération 
never gets stimulated up to thedischarging point, Indysp- 
no the stimulus becomes sufficient to cause it also to 
discharge, but only after the more irritable inspiratory 
contre, hence the expiration follows the inspiration. This 
alternation of activity is, moreover, promoted by the fact 
that the pneumogastric nerve-fibres coming up from the 
long of two kinds. The predominant sort are those 
eferred to, which diminish the resistance to dis- 

‘ge of the inspiratory centre, and perhaps also increase 

the resistance to the expiratory discharge. This set is ex- 
cited when the lungs diminish in bulk, as in expiration; 
and when the whole nerve is stimulated electrically they 
usually get the better of the other get, which carry up to 
the medulla impulses which increase the resistance to in= 








398 THE HUMAN BODY. 
spiratory discharges and diminish that to expiratory, and 
are stimulated when the lungs expand. Hence, every ex- 
pansion of the lungs (inspiration) tends to promote an 
expiration, and every collapse of the lungs (expiration) tends, 
to produce an inspiration; and so, through the pneumo 
gastric nerves, the respiratory mechanism is largely self- 
regulating. 


































Asphyxie. Asphyxia is death from suffocation, or want 
of oxygen by the tissues. It may be brought about in 
various ways; as by strangulation, which prevents the entry 
of air into the lungs; or by exposure in an atmosphere con- 
taining no oxygen; or by putting an animal in @ vacuum; 
or by making it breathe air containing a gas which has a 
stronger affinity for hemoglobin than oxygen has, and 
which, therefore, turns the oxygen out of the red corpuscles 
and takes its place. The gases which do the latter are 
very interesting since they serve to prove conclusively that 
the Body can only live by the oxygen carried round by the 
hwmoglobin of the red corpuscles; that amount dissolved 
in the blood plasma being insufficient for its needs. Of 
such gases carbon monoxide is the most important and best 
studied; in the favorite French mode of committing suicide 
by stopping up all the ventilation holes of a room and 
burning charcoal in it, it is poisoning by carbon monoxide 
which causes death, 
The Relations of Carbon Monoxide to 

If aérated whipped blood, or « solution of oxyhemoglobin, 
be exposed to a gaseous mixture containing carbon mon- 
oxide, the liquid will absorb the latter gas and give off 
oxygen. The amount of carbon monoxide taken up will 
(apart from a small amount dissolved in the plasma) be inde- 
pendent of the partial pressure of that gas in the gaseons 
, mixture to which the blood is expozed; the quantity absorbed 
depends on the quantity of hwmoglobin in the liquid, 
and is replaced by an equal volume of oxygen liberated, 
This equivalence of volume, of itself, proves that the phe 
nomenon is due to the chemical replacement of oxygen 
in some compound, by the carbon monoxide; for if the 
carbon monoxide were merely dissolved in the liquid in 


a 





CARBON-MONOXIDE HEMOGLOBIN, 399 


proportion to its partial pressure on the surface, it would 
turn out no oxygen; the quantity of dissolved gases held 
by a liquid being dependent only on the partial pressure of 
each individual gas on its surface, and unaffected by / 
that of all others. During the taking up of carbon ] 
monoxide the blood changes color in a way that can be 
recognized by a practiced eye; it becomes cherry red instead 
of scarlet. This shows that some new chemical compound 
has been formed in it; examination with the spectroscope 
confirms this, and shows the color change to be due to the 
formation of carbon-monoxide hemoglobin which has a 
different color from oxyhwmoglobin. A dilute solution 
of reduced hemoglobin absorbs all the rays of light in one 
region about the green of the solar spectrum (see Physica), 
and go produces therea dark band; a thin layer of the blood 
of an asphyxiated animal does the same. Dilute solution 
of oxyhwmoglobin absorbs the rays in two narrow regions 
of the solar spectrum ab the confines of the yellow 
and green, and arterial blood does the same. Dilute 
solution of carbon-monoxide hamoglobin, or blood which 
has been exposed to this gas, also absorbs the light in two 
narrow bands of the solar spectram; but these are nearer 
the blue end of the spectrum than the absorption bands 
of oxyhemoglobin. Pure blood serum saturated with oxy- 
gen gas or with carbon monoxide does not specially absorb 
any part of the spectrum; therefore the absorptions when 
hwmoglobin is present, must be due to chemical compounds 
of those gases with that body. 

Since carbon-monoxide-hemoglobin hasa bright red color, 
we find in the Bodies of persons poisoned by that gas, the 
blood all through the Body cherry red; the tissues being 
unable to take carbon monoxide from hamoglobin in the sys- 
temic circulation, Hence the curious fact that, while death 
is really due to asphyxia, the blood is almost the color of 
arterial blood, inatead of very dark purple, as in ordinary 
cases of death by suffocation. Exporiments with animals 
show that in poisoning by carbon monoxide persistent ex= 
posure of the blood to oxygen, by means of artificial respi- 
ration, will cause the poisonous gas to be slowly replaced 



























THE HUMAN BODY. 


again by oxygen; hence if the heart has not yet quite 

stopped beating, artificial respiration, ve up 

should be employed for the restoration of persons 

by carbon monoxide, 

The Phenomena of Asphyxia. As soon as the 

in the blood falls below the normal amount the 

becomes hurried and deeper, and the extraordinary muscles 

of respiration are called into activity. The dyspnma be 

comes more and more marked, and this is especially the 

case with the expirations which, almost or quite passively 

performed in natural breathing, become violently muscular. 

At last nearly all the nruscles in the Body are set at work; 

the rhythmic character of the respiratory acts is Jost, and 

general convulsions occur, but, on the whole, the contrac: 

tions of the expiratory muscles are more violent than those 

of the inspiratory. Thus undue want of oxygen at first 

merely brings about an increased activity of the 

centre, and especially of its expiratory division which isnot 

excited in normal breathing. ‘Then it stimulates other por- 

tions (the conrulsive centre) of the medulla oblongata also, 

and gives rise to violent aud irregalar muscular spasms. 
wo due to excitation of nerve-centres 

eo) be enpposed, to 


and (2) that they etill 
undivided) all the 


requent, at last cease, 











ASPHYXIA. 401 


and the animal appears dead. If, however, its chest be 
opened the heart will be found gorged with extremely dark 
yenous blood and making its last few slow feeble pulsations. 
So long as it beats artificial respiration can restore the ani- 
mal, but once the heart has finally stopped restoration is 
impossible, There are thus three distinguishable 

in death from asphyxia. (1) The stage of dyspnaa. (2) 
‘The stage of convulsions, (3) Thestage of exhaustion; the 
convulsions having ceased but there being from time to 
time an inspiration. The end of the third stage ocenrs in 
a mammal about five minutes after the oxygen supply has 
been totally cut off. If the asphyxia be due to deficiency, 
and not absolute want, of oxygen of course all the stages 
take, longer. 

Circulatory Changes in Asphyxia. During death by 
suffocation characteristic changes occur in the working of 
the heart and blood-vessels. The heart at first beats 
quicker, but very soon, before the end of the dyspnaic stage, 
more slowly, though, at first, more powerfully. ‘This slowing 
is due to the fact that the unusual want of oxygen leads to 
stimulation of the cardio-inhibitory centre in the medulla 
(p. 250) and this, throngh the pneumogastric nerves, slows 
the heart’s beat, Soon, however, the want of oxygen affects 
the heart itself and it begins to beat more feebly, and also 
more slowly, from exhaustion, until its final stoppage. 
During the second and third stages the heart and the venw 
eave become greatly overfilled with blood, because the 
violent muscular contractions facilitate the flow of blood 
to the heart, while its beats become too feeble to send it 
ont again. The overfilling is most marked on the right 
side of the heart which receives the venous blood from the 
Body generally. 

During the first and second stages of asphyxia arterial 
pressure rises ina marked degree. ‘This is due to excitation 
of the vaso-motor centre (p. 254) by the venous blood, and 
the consequent constriction of the muscular coats of the 
arteries and increase of the peripheral resistance. Tn the 
third stage the blood-pressure falls very rapidly, because 
the feebly acting heart then fails to keep the arteries” 














402 THE HUMAN BODY, 


tense, even although their diminished calibre greatly slows 
the rate at which they empty themselves into the capilla- 
ries. 

Another medullary centre unduly excited during asphyxia 
is that from which proceed the nerve-fibres governing 
those muscular fibres of the eye which enlarge the pupil. 
During suffocation, therefore, the pupils become widely 
dilated. At the same time all reflex irritability is lost, and 
touching the eyeball causes no wink; the reflex centres all 
over the Body being rendered, through want of oxygen, in- 
capable of activity. The same is true of the higher nerve- 
centres; unconsciousness comes on during the convulsive 
stage, which, horrible a3 it looks, is unattended with suffer- 
ing. 

Modified Rospiratory Movements. <Sighing is a deep 
long-drawn inspiration followed by a shorter but correspond- 
ingly large expiration. Yawning is similar, but the air is 
mainly taken in by the mouth instead of the nose, and the 
lower jaw is drawn down in acharacteristic manner. ie 
cough depends upon a sudden contraction of the diaphragm, 
while the aperture of the larynx closes; the entering air, 
drawn throngh the narrowing opening, causes the peculiar 
sound. Coughing consists of a full inspiration followed by 
a violentand rapid expiration, during the firet part of which 
the laryngeal opening is kept closed; being afterwards sud- 
denly opened, the air issues forth with a rush, tending to 
carry out with it anything lodged in the windpipe or larynx. 
Sneezing is much like coughing, except that, while in a 
cough the isthmus of the fances is held open and the air 
mainly passes out through the mouth, in sneezing the 
fauces are closed and the blast is driven through the 
nostrils. It is commonly excited by irritation of the nasal 
mucous membrane, but in many persons a sudden bright 
light falling into the eye will produce a sneeze. Laughing 
consists of a series of short expirations following a single 
inspiration; the larynx is open all the time, and the yooal 
cords (Chap.XX XVI.) are set in vibration. Crying is, phy- 
siologically, much like laughing and, us we all know, one 
often passes into the other, The accompanying contrac. 














MODIFIED RESPIRATORY MOVEMENTS. 408 


tions of the face muscles giving expression to the counten- 
ance are, however, different in the two. 

All these modified respiratory acts are essentially reflex, 
but, with the exception of hiccough, they are to a certain 
extent, like natural breathing, under the control of the 
will. Most of them, too, can be imitated more or leas 
perfectly by voluntary muscular movements; though a 
good stage sneeze or cough is rare, 





CHAPTER XXVIL 
THE KIDNEYS AND SKIN. 


General Arrangement of the Urinary Organs. These 
consist of (1) the kidneys, the glands which secrete the 
urine; (2) the wrefers or ducts of the kidneys, which carry 
their secretion to (3) the urinary bladder, ® reservoir in 
which it accumulates and from which it is expelled from 
time to time through (4) an exit tube, the urethra. The 
general arrangement of these parts, as seen from behind, is 
shown in the figure opposite. The kidneys, R, lie in the 
dorsal part of the lumbar region of the abdominal cavity, 
one on each side of the middle line. Each is a solid mass, 
with a convex outer and  concaye inner border, and its 

rm ittle larger than the lower. From the 
a renal artery, Ar, enters the inner 

ey, to break up within it into finer 

ending in capillaries. ‘Che blood is 

0 into the renal veins, Vr, one of whieh 

nd opens into the inferior vena cava, 


f the liquid in the ureter, 
re pressed together and — 





¥i9, 114—The renal of 
; NF & snferioe Ten Potaletet stone regen ¥ rig nena el 








406 THE HUMAN BODY. 


it is closed. TUenally the bladder, which has a thick coat 
of unatriped muscular tissue lined by a mucous membrane, 
is relaxed, and the urine flows readily into it from the 
ureters. The commencement of the urethra being kept 
closed by elastic tissue around it (which can yoluntarily be 
reinforced by muscles which compress the tube) the urine 
accumulates in the bladder. When this latter contracts and 
presses on its contents, the ureters are closed in the way 
above indicated, the elastic fibres closing the urethral exit 
from the bladder are overcome, and the liquid foreed 
out. 

Naked Eye Structure of the Kidneys. These organs 
have externally a red-brown color, which can be seen 
through the transparent capsule of peritoneum which en- 
velops them. When a section is carried through a kidney 
from its outer to its inner border (Fig. 115) it is seem that 
a deep fissure, the Ailus, leads into the latter. In the Atlus 
the ureter widens out to form the pelvis, which breaks up 
again into a number of smaller divisions, the cups or ealices. 
The ent surface of the kidney proper is seen to consist of 
two distinct parts; an outer or cortical portion, and an 
inner or medullary. The medullary portion is less red and 
more glistening to the eye, is finely striated in a radial 
direction, and does not consist of one continuous mass but 
of a number of conical portions, the pyramids of Matpighi, 
2’, each of which is separated from its neighbors by an in- 
ward prolongation,*, of the cortical substance. This, how- 
ever, does not reach to the inner end of the pyramid, 
which projects, as the papilla, into a calyx of the ureter. 
At its outer end each pyramid separates into smaller por 
tions, the pyramids of Ferrein, 2’, separated by thin layers 
of cortex and gradually spreading everywhere into the lat- 
ter. The cortical substance is redder and more granulaf 
looking and less shiny than the medullary, and forms every- 
where the outer layer of the organ next ite capsule, besides 
dipping in between the pyramids in the way described. 

The renal artery divides in the hilus into branches (6) 
which run into the kidney between the pyramids, giving off 
a few twigs to the latter and ending finally in a much 


aN a 


HISTOLOGY OF THE KIDNEYS 


richer vascular network in the cortex. ©The’ branches of 
the renal vein have « similar course. 


Tho Minute Structure of the Kidney. Tho kidneys 
are compound tubular glands, composed essentially of 


rout the right kidney tropa furouter, 
atnid ot Mal ne 


byramise 
earns 


ieroscopic uriniferous tubules, lined by epithe- 

tubule commences at a small opening on 
papi id from thence has a very complex course to its 
other extremity, Usuully about twenty open, side es side, 
on one ares There they have a di 











THE RENAL SECRETION. 


409 


into the renal vein. Most of the blood flowing through the 
kidney thus goes through two sets of capillaries; one in the 


capsules, and a second formed 
by the breaking up of the 
efferent vein of the latter. 
‘The capillary network in the 
pyramids is much less close 
than that in the cortex, which 
gives reason to suspect that 
most of the secretory work of 
the kidneys is done in the cap- 
sules and convoluted tubules. 
‘The pyramidal blood flows 
only through one set of eapil- 
laries, there being no glome- 
rali in the kidney medulla. 
‘The Renal Secretion. The 
amount of this carried off 
from the Body in 24 hours is 
subject to considerable varia- 
tion, being especially dimin- 
ished by anything which pro- 





Fro, 114—The termination of a 
uriniferous tubule, with sie 
ton. 9. the glomerulus or 

). the eon’ ending 


of the tu ates tg i 
fhe at snipe uy 


eae re ata 
inthe giomers. =e 






motes perspiration, and increased by ee cold to 


the surface, which diminish the skin excretion. 


ts average 


daily quantity varies from 1200 to 1750 eub. cent. (40 


to 60 fluid ounces). 


‘The urine is a clear amber-colored 
liquid, of a slightly acid reaction; 


its specific gravity is 


about 1040, being higher when the total quantity excreted 
is small than when it is greater, since the amount of solids 
dissolved in it remains nearly the sume in health; the 
changes in its bulk being dependent mainly on changes 
in the amount of water separated from the blood by the 


kidneys, 


Normal urine consists, in 1000 parta, of about 960 water 


and 40 solids, 


‘The latter are muinly crystalline nitro- 


genous bodies (urea and uric acid), but small quantities of 
pigments and of non-nitrogenous organic bodies are also 


present, and a considerable quantity of mineral salts. 


‘The 


following table gives approximately, in the first column, the 














SOURCES OF UREA, ail 


merely by dialysis or filtration; and others (the specific ele- 
ments of the secretion), especially urea, which are selected 
or made by a special activity of the renal gland-cells. The 
total quantity of the twenty-four hours’ urine thus depends 
Jargely on the pressure in the renal arteries, since the 
higher this is the greater will the amount of filtered liquid 
be. Under ordinary pressures such substances as albumen 
will not filter, but they do under higher; accordingly in 
healthy conditions none of the albumen of the blood plasma 
passes into the urine, but if the pressure in the capillaries of 
the glomeruli is considerably raised it does; its presence in 
the urine being the most prominent symptom of that danger- 
ous class of maladies grouped together under the name of 
Bright's disease, Filtration in the glomeruli is largely pro- 
moted by the fact that the calibre of the efferent vessel of each 
is rather less than that of the afferent; and thus the pressure 
in the thin-walled vessels of the vascular tuft is raised. 

Tho Rélo of the Renal Epithelium. Water and slines 
bemg passed ont mainly through the glomeruli, we have 
now to consider what part the secreting cells of the kidney 
play; and especially as regards urea, the most important 
constituent of the urine. Urea representa the final state 
in which the proteids taken into the Body from the alimen- 
tary canul (or at least their nitrogen) leave, after having 
yielded up, by chemical changes, a certain amount of energy. 
In this process the proteids are oxidized and broken down 
into carbon dioxide and water and urea; and the kidneys 
get rid of the latter, 

Since the life and activity of every tissue is accompanied 
by a breaking down of proteids (though not necessarily at 
once into urea, as many intermediate stages may, and doubt- 
less do, occur in different tissues), there is no donbt that the 
main chemical degradation of albuminous compounds takes 
place outside the kidneys. Whether the final steps by 
which urea is formed oceur in those organs or ¢lsewhere is 
not yet certainly known. According to ono view the urea is 
carried to the kidney in the blood of the renal artery, and 
there merely picked up and passed on by the excreting cells; 
while, according to another, not urea, but the ponul- 

















THE EPIDERMIS, 413 


The rolls of material which are peeled off the skin in the 
“shampooing” of the Turkish bath, or by rubbing with a 
rough towel after an ordinary warm bath, are the dead 
outer scales of the horny stratum of the epidermis, 





Fro. 117.—A section through the epidermis. somewhat diagrammatic, highly 
magnified. Bolow is seen a the dermis, with itwartery. f, and veins, 
pie @, the horny: rer of aay ‘the rete micowum ot Mal) 

favors a, the laver of columnar epideruic calls In immediate contact with the 
deraaly; hy the ductof a sweatgland, 


In dark races the color of the skin depends mainly on 
minute pigment granules lying in the deeper cells of the 
Malpighian layer. 








from the subjacent 

corium. Fine nerve-fibres ran into it and end there 
among the cells, in various ways 

‘The Corium, Cutis Vera, or True Skin, Fig. 118, cos- 

fists fundamentally of a close feltwork of elastic and white 

fibrons tisne, which, becoming wider mesbed below, passes 








710. 118 —A weetton through the sein poetic a a: porey 





A is meshes: 
eae ran 
grudially into the subcutaneous areolar tissue G38) 
which attaches the skin loosely to parts peta 

tanning it is the cudis vera which is turned inte teaeay a 
white fibrous tissue forming an insoluble and tough com- 
pound with the tannin of the oak-bark employed. ‘Wherever 
there are hairs, bundles of plain muscular tissue are found 
in the corium; it contains ulso a close capillary network 


HAIRS. 415 


and numerous lymphatics and nerves. In shaving, so 
long as the razor keeps in the epidermis there is no bleed- 
ing; but a deeper cut shows at once the vascularity of the 
true skin. 

The outer surface of the corium is almost everywhere 
raised into minute elevations, called the papilla, on which 
the epidermis is moulded, 50 that its deep side presents pits 
corresponding to the projections of the dermis, In Fig. 117 
isa papilla of the corivm containing a knot of blood-vessels, 
supplied by the small artery, f, and having the blood carried 

from them by the two little veins, gg. Other papille 
contain no capillary loops but special organs connected 


On the palmar surface of the hand the dermic 
= are especially well developed (as they are in most 
ore the sense of touch is aeute) and are frequently 
or branched at the tip. On the front of the 
are arranged in rows; the epidermis fills up the 
‘een the papille of the same row, but dips down 
ijacent rows, and thus are produced the epidermic 
on the palms. In many places the corium is 
as opposite the finger-joints and’ on the palm. 
such furrows are commonly less marked, but 
ver the whole skin. ‘The epidermis closoly 


tion. of subcutaneous fat and of other soft parts 
skin, which, not shrinking itself at the same 

mes thrown into folds. 
Each hair is a long filament of epidermis devel- 
the top of a special dermic papilla, seated at the 
lepreasion reaching down from the skin into the 
neath and called the hair follicle. The portion of 
in the skin is called its root; this is succeeded 
h, inan uncut hair, tapers off to a point. The 
| by a single layer of overlapping scales form- 
; the projecting edges of these scales 
wards the top of the hair. Beneath the hair 
cuticle comes the cortex, made up of greatly elongated colle 








416 THE HUMAN BODY. 


united to form fibres; and in the centre of the shaft there 
is found, in many hairs, a medulla, made up of more or less 
rounded cells. ‘The color of hair is mainly dependent upon 
pigment granules lying between the fibres of the cortex 
All hairs contain some air cavities, especially in the medulla. 
They are very abundant in white hairs and cause the white 
ness by reflecting all the incidentlight, just asa liquid beaten 
into fine foam looks white because of the light reflected 
from the walls of all the little air cavities in it. In dark 
hairs the air cavities are few. 

‘The hair follicle (Fig. 119) is a narrow pit of the dermis, 
projecting down into the subcutancous areolar tissue, and 
lined by an involution of the epidermis. At the bottom of the 
follicle is a papilla and the 
epidermis, turning up over 
this, becomes continuohs 
with the hair, On the 
papilla epidermie cells 
multiply rapidly so long as 
the hair is growing, and 
the whole hair is there 
made up of roundish cells, 

—Parts of two hairs imbedded As these get pushed up by 
eee gine tee taliies beetke fresh ones formed Decl 

sticur} ¢ themurcies hth +H.em, the outermost layer 

halr, become flattened and form 
the hair cuticle; several succeeding layers elongate and 
form the cortex; while, in hairs with a medulla, the middle 
cells retain pretty much their original form and size, 
Pulled apart by the elongating cortical cells, these central 
ones then form the medulla with its air cavities. The 
innermost layer of the epidermis, lining the follicle, has its 
cells projecting, with overlapping edges turned down- 
wards, Accordingly these interlock with the npward 
directed edges of the cells of the hair cuticle; consequently 
when a hair is pulled out the epidermic lining of the follicle 
is usnally brought with it. So long as the dermio papilla 
is left intact a new hair will be formed, but not otherwise, 
Slender bundles of unstriped muscle (c, Fig, 119) ron from 








ail 


417 


the dermis to the side of the hair follicles, The Jatter are 
obliquely implanted in the skin so that the hairs lie down 
on the surface of the Body, and the museles are so fixed that, 
when they shorten, they erect the hair and cause it to 
bristle, as may be seen in an angry cat, or sometimes in a 
greatly terrified man. Opening into each hair follicle are 
usually a couple of sebaceous glands (p. 418). Hairs are 
found on all regions of the skin except the palms of the 
hands and the soles of the feet; the back of the last phalanx 
of the fingers and toes, the upper eyelids, and one or two 
other regions. 

Nails. Each nail is apart of the epidermis, with its horny 
stratum greatly developed. The buck part of the nail fits 
behind into a furrow of the dermis and is called its root. 
The visible part consists of a body, fixed to the dermis 
beneath (which forms the bed of the nail), and of a free edge. 
Near the root is a little area whiter than the rest of the 
nail and called the funula, The whiteness is due in part 
to the nail being really more opaque there and partly to the 
fact that its bed, which seen through the nail causes its 
pink color, is in this region leas vascular, 

The portion of the corium on which the nail is formed 
is called its mafriz. Behind, this forms a furrow lodging 
the root, and it is by new cells added on there that the nail 
grows in length. The part of the matrix lying beneath the 
body of the nail, and called its ded, is highly vascular and 
raised up into papilla which, except in the region of the 
Junula, are arranged in longitudinal rows, slightly diverging 
as they run towards the tip of the finger or toe. It is by 
new cells formed on its bed and added to its under surface 
that the nail grows in thickness, as it is pushed forward by 
the new growth in length at its root. The free end of a 
nail is therefore its thickest part. If a nail is “cast” in 
consequence of an injury, or torn off, anew one is produced, 
provided the matrix is left. 

The Glands of the Skin are of two kinds, the sudori- 
parous or sweat glands, and the sebaceous or oil glands. 
‘The former belong to the tubular, the latter to the race- 
mose type. The sweat-glands, Fig. 120, lie in the subeu- 








418 THR HUMAN BODY. 


taneous tissue, where they form little globular masses com- 
posed of a coiled tube. From the coil a duct (sometimes 
double) leads to the surface, being 
usually spirally coiled as it passes 
through the epidermis, The secret- 
ing part of the gland consists of a 
connective-tissue tube, continuous 
along the duct with the dermis; 
within this is a basement membranes 
and the final secretory lining consists 
of several layers of gland-cells A 
close capillary network intertwines 
with the coils of the gland. Sweat- 
glands are found on all regions of the 
skin, but more closely set in some 
places, as the palms of the hands and 
the brow, than elsewhere. There are 
altogether about twoand a half millions 
ene A feet of them opening on the surface of the 
fucle: ge Malpighian Body, 
ficistgegsres: ‘The sebaceous glands nearly always 
tancousfatareseeabelow open into hair follicles, and are found 
wherever there are hairs. Euch con- 
sists of a duct opening near the mouth of a hair follicle and 
branching at its other end: the final branches lead into globu- 
lar secreting saccules, which, like the ducts, are lined with 
epithelium. In the saccules the substance of the celle 
becomes charged with oil-drops, the protoplasm disappearing; 
and finally the whole cell falls to pieces, its detritus constitut- 
ing the secretion. New cellsare, meanwhile, formed to take 
the place of those destroyed. Usually two glands are con- 
nected with each hair follicle, but there may be three or 
only one. A pair of sebaceous glands are represented on 
the sides of each of the hair follicles in Fig. 119. 

The Skin Secretions. The skin besides forming a pro- 
tective covering and serving a8  sense-organ (Chap. 
XXXIV.) also plays an important part in regulating the 
temperature of the Body, and, as an excretory organ, in 
carrying off certain waste products from it, 








PERSPIRATION, 419 


The sweat poured out by the sadoriparons glands is a 
transparent colorless liquid, with a peculiar odor, varying 
in different races, and in the samo individual in different 
regions of the Body. Its quantity in twenty-four hours is 
subject to great variations, but usually lies between 700 and 
2000 grams (10,850 and 31,000 grains). The amount is in- 
fluenced mainly by the surrounding temperature, being 
greater when this is high; but it-is also increased by other 
things tending to raise the temperature of the Body, ns 
muscular exercise. The sweat may or may not evaporate 
as fast as it is secreted; in the former case it is known as 
insensible, in the latter as sensible perspiration, By far 
the most passes off in the insensible form, drops of sweat 
only accumulating when the secretion is very profuse, or the 
surrounding atmosphere so humid that it does not readily 
take up more moisture. The perspiration is acid, and in 
1000 parts contains 990 of water to 10 of solids. Among 
the latter are found urea (1.5 in 1000), fatty acids, sodium 
chloride, and other salts, In disenzed conditions of the 
kidneys the urea may be greatly increased, the skin supple- 
menting to a certain extent deficiencies of those organs. 

Tho Nervous and Circulatory Factors in tho Swoat 
Secretion. It used to be believed that an increased flow uf 
blood through the skin would suffice of itself to cause in- 
creased perspiration; but against this view are the facts 
that, in terror for example, there may be profuse sweating 
with a cold pallid skin; and that in many febrile states the 
skin may be hot and its vessels full of blood, and yot there 
may be no sweating. 

Recent experiments show that the secretory activity of 
the sweat-glands is under the direct control of nerve-fibres, 
and is only indirectly dependent on the blood-supply in 
their neighborhood. Stimulating the sciatic nerve of the 
freshly amputated leg of a cat will cause the balls of its 
feet to sweat, although there is no blood flowing throngh 
the limb. On the other hand, if the sciatic nerve be cut, 
so as to paralyze it, in # living animal, the skin arteries di- 
late and the foot gets more blood and becomes warmer; 
but it does not sweat, The sweat-fidres originate in certain 





THE HUMAN BODY. 





sweat-centres in the spinal cord, which may either be di- 
rectly excited by blood of a higher temperature than usual 
flowing through them or, reflexly, by warmth acting on the 
exterior of the Body and stimulating the sensory nerves 
there. Both of these agencies commonly algo excite the 
vaso-dilator nerves of the sweating part, and so the increased 
blood-supply goes along with the secretion; but the two 
phenomena are fundamentally independent. 

‘The Sebaceous Secretion. This is oily, semifinid, and of 
aspecial odor. It contains about 50 per cent of fats (olein 
and palmatin). It lubricates the hairs and usually renders 
them glossy, even in persons who use none of the various 
compounds gold as ‘‘hair-oil.” No doubt, too, it gets 
spread more or less over the skin and makes the enticle leas 
permeable by water. Water poured on a healthy skin does 
not wet it readily but runs off it, as ‘off a duck’s back” 
thongh to a less marked degree. 

Hygiene of the Skin, ‘The sebaceous secretion, and 
the solid residue left by evaporating sweat, constantly 
form a solid film over the skin, which must tend to choke 
up the mouths of the sweat-glands (the so-called * pores” of 
the skin) and impede their activity. Hence the value to 
health of keeping the skin clean: a daily bath should be 
taken by every one. Women cannot well wash their hair 
daily as it takes so long to dry, but a man should immerse 
his head when he takes his bath. As a general rule, soup 
should only be used occasionally; it is quite unnecessary for 
cleanliness, except on exposed parts of the Body, if frequent 
bathing is a habit and the skin be well rubbed afterwards 
until dry. Soap nearly always contains an excess of alkali 
which in itself injures some skins, and, besides, is apt to com- 
bine chemically with the sebaceous secretion and carry it 
too freely away. Persona whose skin will not stand soap 
can find a good substitute, for washing the hands and face, 
in a little cornmeal. No doubt many folk go about in 
yery good health with very little washing; contact with 
the clothes and other external objects keeps its excretions 
from accumulating on the skin to any very great extent. 
But apart from the duty of personal cleanliness imposed on 


[a a 


BATHING. 421 


man as a social animal in daily intercourse with others, 
the mere fact that the healthy Body can manage to get 
along under unfavorable conditions is no reason for expos- 
ing it to them. A clogged skin throws more work on the 
lungs and kidneys than their fair share, and the evil con- 
sequences may be experienced any day when something else 
throws another extra strain on them. 

Animals, a considerable portion of whose skin has been 
yarnished, die within afew hours. This used to be thought 
due to poisoning by retained ingredients of the sweat. 
But the real cause of death seems to be an excessive radia- 
tion of heat from the surface of the body, which the vital 
oxidative processes cannot keep up with, so the bodily tem- 
perature falls until it reaches a fatal point, about 20° O. 
(68° F',) for rabbits, If the animal be packed in raw cotton 
or kept in an atmosphere at a temperature of 30° C. (86° F.) 
it will not die from the varnishing. 

The general subject of bathing may be con- 
sidered hore, One objoct of it is that above mentioned, to 
cleanse the skin; but it is also useful to strengthen and 
invigorate the whole frame. For strong healthy persons 
cold bath is the best, except in extremely severe weather, 
when the temperature of the water should be raised to 15° 
©. (about 60° F.), at which it still feels quite cold to the 
surface. The first effect of acold bath is to contract all 
the skin-vessels and make the surface pallid. This is soon 
followed by a reaction, in which the skin becomes red and 
congested, and a glow of warmth is felt in it. The proper 
time to come out is while this reaction lasts, and after 
emersion it should be promoted by a good rub. If the 
stay in the cold water be too prolonged the state of reaction 
passes off, the skin again becomes pallid, and the person 
probably feels cold, uncomfortable, and depressed all day. 
‘Then bathing is injurious instead of beneficial; it lowers 
instead of stimulating the activities of the Body. How 
long a stay in the cold water may be made with benefit, 
depends greatly on the individual; a vigorous man can bear 
it and set up a healthy reaction after much longer immer- 
sion than a fecble one; moreover, being used to cold bathing 









renders # longer stay safe, and, of course, the tem} 
of the water has a great influence: water called cold” 
may vary within very wide limits of temperature, as indi- 
eated by the thermometer; and the colder it is the shorter 
is the time which it is wise to remain in it. Persons who 
jn the comparatively warm water of Narragansett dur- 
ing the summer months stay with benefit and pleasure 
in the sea, have to content themselves with a single plunge 
on parts of the coast where the water is colder. The 
nature of the water has some influence; the salts contained 
in sea-water stimulate the skin-nerves and promote the 
afterglow. Many persons who cannot stand a simple cold 
fresh-water bath take one with benefit when some salines are 
previously dissolved in the water. The best for this purpose 
are probably those sold in the shops under the name of 
* sea-salts,”” 

It is perfectly safe to bathe when warm, provided the 
skin is not perspiring profusely, the notion commonly pire- 
valent to the contrary notwithstanding. On the other 
hand, no one should enter a cold bath when feeling chilly, 
or in a depressed vital condition. It is not wise to take a 
bath immediately after a meal, since the afterglow tends to 
draw away too much blood from the digestive organs, which 
are then activelyat work. Tho bost time fora long bath ig 
about three hours after breakfast; but for an ordinary daily 
dip, lasting but a short time, there is no better period than 
on rising and while still warm from bed. 

‘Tho shower-bath abstracts less heat from the skin than 
an ordinary cold bath and, at the sime time, gives it a 
greater stimulus: hence it has certain advantages. 

Persons in feeble health may diminish the shock to the 
system by raising the temperature of the water they bathe 
in up to any point at which it still feels cool to the skin. 
Bathing in water which feels warm is not advisable: it tends 
generally to diminish the vital activity of the Body. Henee 
warm baths should only be taken occasionally and for 
special purposes, 


= ail 


THE HUMAN BODY. 









CHAPTER XXVIII. 
NUTRITION. 


‘The Problems of Animal Nutrition. We have in pre- 
ceding chapters traced certain materials, consisting of foods 
more or less changed by digestion, into the Body from the 
alimentary canal, and oxygen into it from the lungs. We 
have also detected the elements thus taken into the Body 
in their passage out of it again by lungs, kidneys and skin; 
and found that for the most part their chemical state was 
different from that in which they entered; the difference 
being expressible in general terms by saying that more 
oxidized forms of matter leave the Body than enter it. 
Wo have now to consider what happens to each food d 
the journey through the Body: is it changed at all? is it 
oxidized? if so where? what products does its oxidation 
give rise to? Is the oxidation direct and complete at once 
or doos it ocour in successive steps? Has the food been 
used first to make part of a living tissue and is this then 
oxidized; or has it been oxidized without forming part of a 
living tissue? if so,where? in the blood stream or ontside 
of it? Finally, if the chemical changes undergone in 
the Body are such as to liberate energy, how has this energy 
been utilized? to maintain the temperature of the Body or 
to give rise to muscular work, or for other purposes? This 
is a long string of questions, the answers to many of which 
Physiology has still to seek. 

The Seat of the Oxidations of the Body. According 
to older views oxidation mainly took place in the blood 
while flowing through the lungs. Those organs were con- 
sidered a sort of furnace in which heat was liberated by 
blood oxidation, and then distributed by the circulation. 












au 





THE HUMAN BODY. 


But if this were so the lungs ought to be the hottest 
of the Body, and the blood leaving them by the pulmonary 
veins much hotter than that brought to them by the pulmo- 
nary artery after it had been cooled by warming all the tis- 
sues; and neither of these things is true. A small amount 
of heat is liberated when hemoglobin combines with oxygen 
in the pulmonary capillaries, but the affinities thus satisfied 
are 50 feeble that the energy liberated is trivial in amount 
when compared with that set free when this oxygen subse- 
quently forms stabler compounds elsewhere. It isnow, more- 
over, tolerably certain that hardly any of this latter class of 
oxidations oceurs in the living circulating blood at all; its 
cells do, no doubt, use up some oxygen and set free some car- 
bon dioxide; but not enongh to be detected by ordinary 
methods of analysis. The percentage of oxygen liberated in a 
vacuum by two specimens of the blood of an animal, taken 
one from an artery near the heart, and the other froma distant 
one, are practically the same; showing that during the time 
occupied in flowing two or three feet through an artery the 
blood uses up no appreciable quantity of its own oxygen; 
while in the short time occupied in its brief capillary transi 

it loses so much oxygen as to become yenons, The differ- 
ence isexplained by the fact that the blood gives off oxygen 
gas through the thin capillary walls to the surrounding 
tissues; and in them the oxidation takes place. As we 
have already seen, a freshly excised muscle deprived of 
blood can still be made to contract; and for some consider- 
able time if it be the muscle of a cold-blooded animal. 
During its contraction it evolves large amounts of carbon 
dioxide, although the resting fresh muscle contains hardly 
any of that gas. Here we have direct evidence of oxidation 
taking place in a living tissne and in connection with its 
functional activity; and what is true of a muscle is prob- 
ably true of all tissues; the oxidations which supply them 
with energy take place within the living cells themselves. 
The statement frequently made that the oxygen im the eir- 
culating blood exists as ozone, rests on no sufficient basis; 
decomposing hemoglobin does seem to form ozone when 
exposed to the air, but fresh blood yields no sign of it. 










=| 


SYNTHESES IN THE BODY. 425 


Experiments made by adding various combustible sub- 
stances, as sugar, to fresh blood, also fail to prove the oc- 
currence of any oxidation of such bodies in that liquid. 

Tissue-Building and Energy-Yiolding Foods. The 
Human Body, like that of other animals, is, on the whole, 
chemically destructive; it takes in highly complex sub- 
stances as food, and eliminates their elements in much 
simpler compounds, which can again be built up to their 
original condition by plants. Nevertheless the Body has 
certain constructive powers; it, atleast, builds np protoplasm 
from proteids and other substances received from the 
exterior; and there is reason to believe it does a good deal 
more of the same kind of work, though never an amount 
equaling its chemical destructions, Given one single pro- 
teid in its food, say egg albumen, the Body can do very 
well; making seram albumen and fibrin factors out of it 
for the blood, myosin for the muscles, and so on: in such 
cases the original proteid must have been taken more or 
less to pieces, remodeled, and built up again by the living 
tissues; and it is extremely doubtful if anything different 
occurs in other cases, when the proteid eaten happens to be 
one found in the Body. In fact, during digestion the pro- 
teids are broken down somewhat, and turned into peptones; 
in this state they enter the blood and must again be built 
up into proteids, either there or in the solid tissues. 

‘The constructive powers of the Body used to be rather 
too much ignored. Foods were divided into assimilable and 
combustible, the former serving directly to renew the organs 
or tissues as they were used up, or to supply materials for 
growth; these were mainly proteids and fats; no special 
chemical synthesis was thus supposed to take place, the 
living cells being nourished by the reception from outside of 
molecules similar to those they had lost. Fat-cells grew 
by picking up fatty molecules, like their contents, received 
from the food; and protoplasmic tissues by the reception 
of ready-made proteid molecules, needing no farther 
manufacture in the cell, The combustible foods, on the 
other hand, were the carbohydrates and some fats: these, 
according to the hypothesis, were incapable of being made 











426 THE HUMAN BODY. 


into parts of a living tissue, and were simply burnt at once 
in order to maintain the bodily warmth. It been 
proved, however, that more fat might accumulate in the 
body of an animal than was taken in its food, this excess 
was accounted for by supposing it was due to excess of com- 
bustible foods, converted into fats and stored away as oil- 
droplets in varions cells; but not actually built up inte true 
living adipose tissue. Licbig, somewhat similarly, classed 
all foods into plastic, concerned in making new tissues, and 
respiratory, directly oxidized before they ever constituted 
a tissue. The plastic foods were the proteids, but these 
also indirectly gave rise to the energy expended in museu- 
lar work, and to some heat: the proteid museular fibre 
being broken first into a highly nitrogenous part (urea, or 
some body well on the road to become urea) and a non- 
nitrogenized richly hydrocarbonous part; and this latter 
was then oxidized and gave rise to heat. Several facts may 
be urged against this view—(1) Men in tropical climates 
live mainly on non-proteid foods, yet their chief needs are 
not heat production, but tissue formation and muscular 
work: according to Licbig’s view their diet should be 
mainly nitrogenous. (2) Carnivorous animals live on a 
diet very rich in proteida, nevertheless develop plenty of 
animal heat, and that without doing the excessive museu- 
lar work which, on Liebig’s theory, must first be gone 
through in order to break up the proteids, with the produc- 
tion of a non-azotized part which could then be oxidized for 
heat-production. (3) Great muscular work can be done on 
a diet poor in proteids; beasts of burden are for the most 
part herbivorous. (4) Further, we know exactly how much 
energy can be liberated by the oxidation of proteids to that 
stage which oceurs in the Body; and it is perfectly possible 
to estimate pretty accurately the amount of urea and uric 
ucid exereted in a given time; from their sum the amount 
of proteid oxidized and the amount of energy liberated in 
that oxidation can be calculated; if this be done it is found 
that, nearly always, the muscular work done during the 
same period represents far more energy expended than could 
bo yielded by the proteids broken down, 


SOURCE OF MUSCULAR WORK. 427 


The Source of the Energy Expended in Muscular 
Work. This question, which was postponed in the chap- 
ters dealing with the muscular tissues, on account of its 
importance demands here a discussion. It may be put thus: 
—Does a muscle-fibre work by the oxidation of its proteids, 
i.e. by breaking them down into compounds which are 
then removed from it and conveyed ont of the Body? or 
does it work by the energy liberated by the oxidation of 
carbon and hydrogen compounds only? The problem may 
be attacked in two ways; first, by examining the excretions 
of a man, or other animal, during work and rest; second, 
by examining directly the chemical changes produced in a 
muscle when it contracts. Both methods point to the same 
conclusion, viz, that proteid oxidation is not the source of 
the mechanical energy expended by the Body. 

One gram (15.5 grains) of pure albumen when completely 
burnt liberates, a8 heat, an amount of energy eqnal to 2117 
kilogrammeters (15,270 foot-pounds). But in the Body 
proteids are not fully oxidized; part of their carbon is, to 
form carbon dioxide, and part of the hydrogen, to form 
water; but some carbon and hydrogen pass out, combined 
with nitrogen and oxygen, in the incompletely oxidized 
state of urea, Therefore all of the energy theoretically ob- 
tainable is not derived from proteids in the Body: from 
the above full amount for each gram of proteid we must 
take the quantity carried off in the urea, which will be the 
amount liberated when that urea is completely oxidized. 
Each gram (15.5 grains) of proteid oxidized in the Body gives 
kof agram (5.14 grains) of urea; and since one gram of 
urea liberates, on oxidation, energy amounting to 934 kilo- 
grammeters (6740 foot-pounds) each gram of proteid 
oxidized, so far as is possible in the Body, yields during the 
proccess 2117— 244 = 1805.7 kilogrammeters (13,037 foot- 
pounds) of energy. Knowing that urea carries off practi- 
cally all the nitrogen of proteids broken up in the Body, and 
contains 46.6 per cent of nitrogen, while proteids contain 
16 per cent, it is easy to find that each gram of urea repre- 
sonts the decomposition of abont 2.80 grams of proteid and, 
therefore, the liberation of 5060.00 kilogrammeters (36,533.0 











428 THE HUMAN BODY. 


foot-pounds) of energy. If, therefore, we know how much 
urea 4 man excretes during a given time, and how much 
mechanical work he does during the same time, we can 
readily discover if the latter could possibly have been done 
by the energy set free by proteid decomposition, Let us 
take a special case. Fick and Wislecenus, two German 
observers, climbed the Faulhorn mountain, which is 1956 
meters (about 6416 feet) high. Fick weighed 66 kilograms 
and, therefore, in lifting his Body alone, did during the 
ascent 129,096 kilogrammeters (932,073 foot-pounds) of 
work. Wislecenus, who weighed 76 kilograms, did similarly 
148,656 kilogrameters (1,073,296 foot-pounds) of work. 
But during the ascent, and for five hours afterwards, Fick 
secreted urine containing urea answering only to 37.17 
grams of proteid, and Wislecenus urea answering to 37 
grams. Since each gram of proteid broken up in the Body 
liberates 1805.7 kilogrammeters (13,037 foot-pounds) of 
energy, the amount that Fick could possibly haye obtained 
from such a source is 1805.7 x 37.17 = 67,117 kilogram- 
meters (484,584 foot-pounds), and Wislecenns 1805.7 X 37 
= 66,810 kilogrammeters. If to the muscular work done 
in actually raising their bodies, we add that done simul- 
taneously by the heart and the respiratory muscles, and in 
such movements of the limbs as were not actually concerned 
in liting their weight, we should have, at least, to double 
the above total muscular work done; and the amount of 
energy liberated meanwhile by proteid oxidation, becomes 
utterly inadequate for its execution. Tt is thus clear that 
musenlar work is not wholly done at the expense of the 
oxidation of muscle proteid, and it is very probable that 
none is so done under ordinary circumstances, for the nrea 
excretion during rest is about as great as that during 
work, if the diet remain the same; if the work is very 
violent, asin long-distance walking matches, the urea quan- 
tity is sometimes temporarily raised but this increase, 
which no doubt represents an abnormal wear and tear of 
musele-fibre, is probably independent of the liberation of 
energy in the form in which a muscle can use it, more 
likely taking the form of heat; and is, moreover, compen- 


URKA AND MUSCULAR WORK. 429 


suted for afterwards bya diminished urea excretion. Thus, 
hourly, before the ascent Fick and Wislecenus each ex- 
ereted on the average about 4 grams (62 grains) of urea; 
during the ascent between 7 and 8 grams (108-124 grains); 
but during the snbsequent 16 hours, when any urea formed 
in the work would certainly have reached the urine, only 
an average of about 3 grams (46.5 grains) per hour. 

It may still be objected, however, that a good deal of the 
muscle work may be done by the energy of oxidized muscle 
proteid; that the amount of this oxidation occurring in a 
muscle during rest or ordinary work is pretty constant and 
simply takes different forms in the two cases, much as a 
steam-ongine with its furnance in fall blast will burn as 
much coal when working as when resting, but in the former 
case lose all the energy generated in the form of heat, and 
in the latter partly as mechanical work. Thus the want of 
increase in urea during muscular activity would be explained, 
while still a good deal of utilizable energy might come from 
proteid degradation. But if this were so, then the work- 
ing Body should eliminate no more carbon dioxide than the 
resting; the amount of chemical changes in its muscles 
being by hypothesis the same, the carbon dioxide eliminated 
should not be increased. Experiment, however, shows 
that it is, and that to a very large extent, even when the 
work done is quite moderate and falls within the limits 


which could be performed by the normal proteid degrada- 


tion of the Body. Quite easy work doubles the carbon 
dioxide excreted in twenty-four hours, and in a short period 
of very hard work it may rise to five times the amount 
eliminated during rest, Since the urea is notincreased, or but 
very slightly increased, at the same time,this carbon dioxide 
cannot be due to increased proteid metamorphosis; and 
it therefore indicates that a muscle works by the oxidation 
of carbonaceous non-nitrogenous compounds. Since all 
the carbon compounds oxidized in the Body contain hydro- 
gen this clement is also no doubt oxidized during muscu- 
lar work; but its estimation is difficult and has not been 
attempted, because the Body contains so much water ready 
* formed that a large quantity is always ready for increased 








™~ 





430 THE HUMAN Bopy. 


evaporation from the lungs and skin, whenever the respira- 
tions are quickened, as they are by exercise. It, thus, is very 
difficult to say how much of the extra water eliminated 
from the Body during work is due merely to this cause and 
how much to increased hydrogen oxidation. 

The conclusion we are led to is, then, thatamuscle works 
by the oxidation mainly, if not entirely, of carbon and 
hydrogen; much as a steam-engine does: the proteid con- 
stituents of the muscle answer roughly to the metallic parts 
of the engine, to the machinery using the energy liberated 
by the oxidations, but in itself only suffering wear and tear 
bearing no direct proportion to the work done; as an engine 
may rust, so muscle proteid may and does oxidize, but not 
to supply the organ with energy for nse. This conclusion, 
arrived at by a study of the excretions of the whole Body, is 
confirmed by the results obtained by the chemical study of 
asingle muscle. A fresh frog’s muscle (which agrees in all 
essential points with a man’s) contains practically no car~ 


bon dioxide, yet, made to w in & vacuum, gives off that 
gus, and more the more Some carbon dioxide is 
therefore formed in the work muscle. If the musele, 
after onleatiangi as ag mgd as it be thrown into death 

; and if taken per- 
feotly fresh an rtis without contracting 
it gives off. carb mount exactly equal to. 


‘The muscle must, 
arbon-dioxide-yield- 
is associated with 


a worked muscle 
he total carbohy- 





CHEMISTRY OF WORKING MUSCLE. 431 


the oxygen a muscle uses in contracting is not taken up by 
it at the time it is used, since a muscle containing no oxy- 
gen will still contract and evolve carbon dioxide in a vacuum. 
Itis probable that the chemical phenomena occurring in con- 
traction and rigor are essentially the same; the death stiffen- 
ing results when they occur to an extreme degree. Pro- 
visionally one may explain the facts as follows—A muscle in 
the Body takes up from the blood, oxygen, proteids, and 
non-nitrogenous (carbohydrate or fatty) substances. These 
it builds up into a highly complex and very unstable com- 
pound, comparable, for example, to nitro-glycerine. When 
the muscle is stimulated this falls down into simpler sub- 
stances in which stronger affinities are satisfied; among 
these ure carbon dioxide and sarcolactic acid and a proteid 
(myosin). The energy liberated is thus independent of 
any simultaneous taking up of oxygen; the amount possible 
depends only on how much of the decomposable body exists 
in the muscle. Under natural conditions the carbon 
dioxide is carried off in the blood and perhaps the sarco- 
lactic acid also, the latter to be elsewhere oxidized farther 
to form water and more carbon dioxide. The myosin 
remains in the muscle-fibre and is combined with more 
oxygen, and compounds of carbon and hydrogen taken from 
the blood, and built up into the unstable‘ energy-yielding 
body again; none of it, under ordinary circumstances, 
leaves the muscle. If, however, the blood-supply be defi- 
cient, the myosin clots (p. 125) before this restitution takes 
place and it cannot then be rebuilt; and in excessive work 
the same thing partially occurs, the decomposition oceur- 
ring faster than the recomposition; the clotted myosin is 
then broken up into simpler bodies and yields a certain 
increase of the urea excreted. In rigor mortis all the myosin 
passes into the clotted state and causes the rigidity. A 
working muscle takes up more oxygen from the blood than a 
resting one, as is shown by a comparison of the gases of its 
venous blood in the two cases; this oxygen assumption is 
not necessarily proportionate to the carbon-dioxide elimina- 
tion at the same time; for the latter depends on the break- 
ing down of a body already accumulated in the muscle dur- 





432 THE ‘HUMAN BODY. 


ing rest, and this breaking down may occur faster than the 
eeeareae We are thus enabled, also, to understand 
how, during exercise, the carbon dioxide evolved from the 
Inngs may contain more oxygen than that taken yp at the 
same time; for it is largely oxygen previously stored dur- 
ing rest, that then appears in the carbon dioxide of the ex- 
ees air. 
any Foods Respiratory in Liebig’s Sonse of the 
= “we find, then, that Liebig’s classification of foods 
cannot be accepted in an absolute sense. There is nodoulit 
that the substance broken down in muscular contraction is 
proper living muscular tissue; and if this (its proteid con- 
stituent being retained) be reconstructed from foods con- 
taining no nitrogen (whether carbohydrates or fats) then 
the term plastic or tissue-forming cannot be restricted to 
the proteids of the dict. We must rather conclude that 
any alimentary principle containing carbon may be used to 
replace the oxidized carbon, and any containing hydrogen 
to replace the oxidized hydrogen, of a tissue; and so even 
non-proteid foods may be plastic. A certain proportion of 
the foods digested may perhaps be oxidized to yield energy, 
before they ever form part of a tissue; and so correspond 
pretty much to Liehig's respiratory foods; but no hard and 
fast. line can bé drawn, making all proteid foods plastic 
and all oxidizable non-proteid foods respiratory. 

Luxus Consumption. Not only, as above pointed out, may 
non-nitrogenous foods be plastic, but it is certain that if 
any foods are oxidized at once before being organized into 
a tissue, proteids are under certain circumstances; namely, 
when they are contained in excess in a diet. Tf an animal 
be starved it is found that its non-nitrogenous tissues go 
first; an insufficiently fed animal loges its fat first, and if it 
ultimately dics of starvation, is found to have lost 97 per cent 
of its adipose tissue and only about 30 per cent of its 
proteid-rich muscular tissue, und almost none of its brain 
and spinal cord; all of course reckoned by their dry weight. 
It is thus clear that the proteids of the tissues resist oxida- 
tion much better than fat does, But, on the other hand, if 
a well-fed animal be given a very rich proteid diet all the 





SOURCES OF UREA. 433 


nitrogen of its food reappears in its urine, and that when 
it is laying up fat; so that then we get a state of things in 
which proteids are broken up more easily than fats. ‘This 
indicates that proteid in the Body may exist under two 
conditions; one, when it forms part of a living tissue and is 
protected to a great extent from oxidation, and another, in 
which it is oxidized with readiness and is presumably in 
different condition from the first, and not yet built up into 
part of aliving cell. he use of proteids for direct oxidation 
is known as /uzus consumption; how far it oceurs under 
ordinary cireumstances will be considered presently. The 
main point now to be borne in mind is that while all organic 
non-nitrogenons foods cannot be called respiratory, neither 
can proteids under all circumstances be called plastic, in 
Liebig’s sense. 

‘The Antecedents of Urea. In the long run the pro- 
genitors of the ureavxcreted from the Body are the proteids 
taken in the food; but it remains still to be considered 
what intermediate steps these take before excretion in the 
urine; and whether area itself ix finally formed in the kid- 
neys or merely separated by them from the blood. 

Tn seeking antecedents of urea one natarally turns first 
to the muscles, which form by far the largest mass of pro- 
teid tissues in the Body. Analysis shows that they always 
contain kreatin, a body intermediate chemically between 
proteids and urea, The quantity of this in muscles is pric 
tically unaffected by work, and is from 0.2 to 0.4 per cent. 
‘Since it is readily soluble and dialyzable, and therefore fit- 
ted to pass rapidly out of the muscles into the blood stream, 
it isa fair conclusion that a good deal of it is formed in 
the muscles daily and carried off from them. Kreatin, 
too, exists in the brain, and probably there, and elsewhere 
in the nervous system, is produced by chemical degrada- 
tion of protoplasm; the spleen ulso contains a good deal of 
kreatin, and so do many glands. This substance would 
therefore seem to be constantly produced in considerable 
quantities by the protoplasmic tissnes generally; and since 
it belongs to a group of nitrogenous compounds which the 
Body is unable to utilize for reconstruction into proteids, 





434 THE HUMAN BODY. 


it must be carried off somehow. The urine, 
tains very little kreatin, or its immediate derivative, 
tinin, and what it does contain mainly 
feeding, since it varies with the diet and vanishes 
starvation; so it is probable that this substance is con- 
yerted into urea and excreted in that form. This conver- 
sion must occur elsewhere than in the muscles, which con- 
tain no urea; also, very little, if any, exists in the brain. 
Where the kreatin is finally changed into urea is dotbt= 
fal. It may be in the kidneys by the renal 
or it may be elsewhere, and the urea produced be merely 
picked up from the blood and passed out by the 
cells; or both may occur; histologically the disti 
secretory epitheliums of the convoluted parts of the tubules 
and of Henle’s loops, differ so much as to suggest an en- 
tirely different function for them. 
On the whole, the evidence seems to show that urea is 
merely separated and not produced in the kidneys; a 
this is more probable, since in the degradation of kreatin to 
liberated and this might very well be 
utilized i in some organ; while if the process took place in 


ins urea, and renal. 
I-vein blood, which shows that 


hen pent of proteid 
ly increased and 





LUXUS CONSUMPTION. 435 


and before we can well suppose the proteids eaten to have 
been built up into tissnes, and thesein turn broken down; in 
fact there need be, and usually is, ander such cireamstances 
no sign of any special activity of any group of tissues, such 
as one would expect to see if the urea always came from the 
breaking down of formed histological elements, This urea 
is thus indicative of a utilization of proteids for other than 
plastic purposes; and the same fact is indicated by the 
storage of carbon and elimination of all the nitrogen of the 
food (p. 444) when a diet very rich in proteid alimentary 
principles is taken. This Jeceus consumption may be com- 
pared to the paying out of gold by a merchant instead of 
greenbacks when he has an abundance of both. Only the 
gold can be used for certain purposes, as settling foreign 
debts, but any quantity above that needed for such a pur- 
pose is harder to store than the paper money and not so 
convenient to handle; so it is paid out in preference to 
the paper money, which is really somewhat less valuable, as 
available at par only for the settlement of domestic debts. 
In artificial pancreatic digestions, when long carried on, 
two bodies, called leucin and tyrosin, are produced from 
proteids. It is found that when lencin is given to an 
animal in its food it reappears in the urine as urea; so 
the Body can turn leucin into that substance. Hence a 
possible source of some of the luxus-consumption urea is 
Jeucin produced during intestinal digestion; and this is 
very likely turned into urea in the liver. At any rate 
the liver, to which the portal vein might carry all leucin 
thus formed, contains urea, which no other gland does; and 
when the liver is greatly altered, as in phosphorus poison- 
and the disease known as acute yellow atrophy, urea 
ntirely disappears from the urine. This latter fact 
) point to a final production of urea in the liver, what- 
ever its immediate antecedents may be; whether muscle 
kreatin, or intestinal leucin, or excess of peptones in the 
diet. The latter might perhaps be broken up there into a 
nitrogenous part (urea) and a non-nitrogenous part; and we 
shall find that a non-nitrogenous substance (glycogen) is 
stored in the liver. 








436 THE HUMAN BODY. 


Protoid Starvation and Overfeeding. When an ani- 
mal is fed on food deficient in proteids, or containing none 
of them at all, its urea excretion fulls very rapidly during 
the first day or two, but then much more slowly until 
death: there is thus indicated a double source of urea, a part 
resulting from tissue wear and tear, and always present; and 
4 part resulting from the breaking down of proteids not 
bailt up into tissue, and ceasing when the amount of this 
proteid in the Body (in the blood for example) falls below 
a certain limit as a result of the starvation. As the 
nitrogen-starved Body wastes, its bulk of proteid tissues 
is slowly reduced and the urea resulting from their degrad- 
ation diminishes also. How well proteid built up into a 
tissue resists removal is shown by the facts already men- 
tioned (p. 432) as to the relative losses of the proteid-rich 
and proteid-poor tissues in starvation. 

On the other hand, if an animal be taken while starying 
and losing weight and have a amall amount of flesh given 
it, it will continue to lose weight, and more urea thay 
before will appear in the urine; increased proteid diet in- 
creases the proteid metamorphosis, and the animal still 
loses, though less rapidly than itdid. A little more proteid 
still increases proteid metamorphosis in the body, and 
the urea elimination, and so on for some time; but each 
increment of proteid in the food increases the nitrogenous 
metamorphosis somewhat less than the last did, until, 
finally, a point is reached at which the nitrogen egesta and 
ingesta balance: in a dog this occurs when it gets daily 
#s its weight of meat, and no other solid food. More food 
if then given is at first stored up and the animal increases in 
weight; but very soon the greater wear and tear of the 
larger mass of tissnes shows itself as increased urea ex- 
oretion; in the egesta and ingesta balance, and the ani- 
mal comes to a new weight equilibrium at the higher level. 
More meat now causes a repetition of the phenomenon: at 
first increase of tissue, and nitrogen storage; and then a 
cessation of the gain in weight, and an excretion in twenty- 
four hours of all the nitrogen taken. And so on, until the 
animal refuses to eat any more, 











STORAGE TISSUES. 437 


‘These facts seem, very clearly, to show that proteids can- 
not be built up quickly into tissues. Meat given to the 
starving animal has its proteids, at first, used up mainly in 
lnxus consumption—while a little is stored as tissue, though 
at first not enough to counterbalance the daily tissue waste. 
When a good deal more proteid is given than answers to 
the nitrogen excretion during starvation, the animal builds 

» np as much into living tissues as it breaks down in the vital 
processes of these, therest going in /uarus consumption; itthus 
neither gains nor loses. More proteid does not all appear in 
the urine at once: some is used to build up new tissue, but 
only slowly; then, after some days, the increased metabolism 
of the increased flesh balances the excess of nitrogen in the 
diet, and equilibrium is again attained. But, all through, it 
seems clear that the tissue formation is slow and gradual; 
and so it becomes additionally probable that the increased 
urea excretion soon after a meal is not due to rapidly in- 
creased tissne formation and degradation, but to a more 
direct proteid oxidation, 

‘The Storage Tissues. Every healthy cell of the Body 
contains at any moment some little excess of material laid 
by in itself, above what is required for its immediate neces- 
F ‘The capacity of contracting, and the concomitant 
© olution of carbon dioxide, exhibited by an excised muscle 
in a vacuum, seem to show that even oxygen, of which 

warm-blooded animals have bat a small reserve, may be 

stored up in the living tissues in such forms that they can 
ilize it, even when the air-pump fails to extract any from 
them. Butin addition to the supplies for immediate spend- 
ing, contained in all the cells, we find special food reserves 
in the Body, on which any of the tissues can call at need. 
These, especially the oxygen and proteid reserves, are found 
¢ the blood. Special oxygen storage is, however, 


red unnecessary by the fact that the Body can, 
very unusual circumstances, get more from 

the air at time, so the quantity of this substance laid 
by is only small; hence death from asphyxia follows very 
rapidly when the air-passages are stopped, while, on account 
of the reserves laid up, death from other forms of starva= 





438 THE HUMAN BODY, 


tion is a much slower occurrence, Proteids, also, we have 
learnt from the study of muscle, are probably but little con- 
cerned in energy-production in the tissues. 

broadly, the work of the Body is carried on by the oxidation 
of carbon and hydrogen, and we find in the Body, in corre- 
spondence with this fact, two great storehouses of fatty and 
carbohydrate foods, which serve to supply the materials for 
the performance of work and the maintenance of the bodily . 
temperature in the intervals between meals, and during 
longer periods of starvation. One such store, that of car- 
bohydrate material, is found in the liver-cells; the other, 
or fatty reserve, is found in the adipose tissue. That such 
substances are trae reserves, not for any special local purpose 
but for the use of the Body generally, is shown by the way 
they disappear in starvation; the liver reserve in afew days, 
and the fat somewhat later and more slowly, but very largely 
before any of the other tissues have been seriously affected. 
By using these accumulated matters the Body can work 
and keep warm during several days of more or less deficient 
feeding; and the fatter an animal is at the beginning of a 


tissues. 
before tl 
ir muscular and nervous 
ished in mass. During the 
y needed to keep the heart and 
, and to maintain the tempers 
2 tained from the oxida 
the animal started. 





GLYCOGEN. 489 


meals this substance is then doled out gradually, and sent 
round the Body in the blood. If a liver be cut up two or 
three hours after removal from the body of a healthy well- 
fed animal, and thoroughly extracted with water, it will 
yield up much grape sugar. If, on the other hand, a per- 
fectly fresh liver be heated rapidly to the temperature of 
boiling water, and then pounded up and extracted, it will 
yield a milky solution, containing little grape sugar but 
much glycogen; a substance which chemically has the same 
empirical formula as starch (CsHioQs), and in other ways 
is closely allied to that body. ‘The salivary and pancreatic 
secretions rapidly convert it into sugar, as they do starch, 
the elements of a molecule of water being taken up at the 
same time— 
Cds + Ho = OsHLivOe 


The same Soe is fase ort by ferments 
present in the blood and liver, and hence the first thing to 
be done in preparing glycogen is to heat the organ at once 
to a temperature high enough to destroy these ferments. 
Pure glycogen is a white amorphous inodorous powder, 
readily soluble in water, forming an opalescent milky solu- 
tion; insoluble in alcohol, and giving with iodine a red 
coloration which disappears on heating and reappears on 
cooling again. 
About four per cent of glycogen can be obtained from 
the liver of a well-nourished animal (dog or rabbit). This 
* for the human liver, which weighs about 1500 grams (53 oz.), 
would give about 60 grams (2.1 o2.) of glycogen at any one 
moment. The quantity actually formed daily is, however, 
much in excess of that, since glycogen is constantly being 
removed from the liver and carried elsewhere, while a fresh 
supply is formed in the organ. Its quantity is subject, also, 
to considerable fluctuations; being greatest about two hours 
after a good meal, and falling from that time until the next 
digestion period commences, when it begins to rise until it 
reattains its maximum. When a warm-blooded animal 
is starved the glycogen entirely disappears from its liver in 
the course of four or five days. Glycogen is, thus, clearly 








440 THE HUMAN BODY. 


being constantly used up, and its maintenance in normal 
quantity depends on food. 

The Source and Destination of Liver Glycogen. All 
foods are not equally efficacious in keeping up the stock of 
glycogen in the liver; fats by themselves are useless; pro- 
teids by themselves give a little; but by far the most is 
formed on a diet rich in starch and sugar; so it would seem 
that glycogen is mainly formed from carbohydrate materials 
absorbed from the alimentary canal and carried to the 
hepatic cells by the portal vein. These materials are 
mainly glucose, since the starch eaten is changed into that 
substance before absorption. This view of the matter is 
supported by several facts. (1) Grape sugar if it exist 
in the blood in abovea certain small percentage passes out 
by the kidneys and appears in the urine, constituting the 
characteristic symptom of the disease called diabetes. In 
health, however, even after a meal very rich in carbohy= 
drates, no sugar appears in the urine; so that the lntge 
quantity of it absorbed from the alimentary canal, within a 
brief time under such circumstances, must be stopped 
somewhere before it reaches the general blood current. (2) 
Glucose injected into one of the general veins of an animal, 
if in any quantity, soon appears in the urine; but the same 
amount injected into the portal vein, or one of its radicles, 
causes no diabetes, but an accumulation of glycogen in 
the liver. We may therefore conclude that the grape sugar 
absorbed from the alimentary canal is taken by the portal 
vein to the liver; there stayed and converted into glycogen; 
which is then more slowly passed on into the hepatic 
veing during the intervals between meals, ‘Thus in spite 
of the intervals which elapse between meals the carbo- 
drate content of the blood is kept pretty constant: dur- 
¢ digestion it is not suffered to rise very high, nor dur 
g ordinary periods of fasting to fall very much below the 
average. 

In what form glycogen leaves the liver is not certain; 
it might be dissolved out and carried off as such, or 
previously turned again into glucose and sent on in that 
form; since the blood and the liver both seem to contain 








GLYCOGEN. 


ferments capable of changing glycogen into glucose the 
latter view is the more probable. Analyses of porial 
and hepatic bloods, made with the view of determining 
whether more sugar was carried out of the liver during 
fasting than into it, are conflicting. ‘The main fact, how- 
ever, remaina that somehow this carbohydrate reserve in 
the liver is steadily carried off to be used elsewhere: and 
animal glycogen thus answers pretty much to vegetable 
starch, which, made in the green leaves, is dissolved and 
carried away by the sap currents to distant and not green 
parts (as the grains of corn or tubers of a potato, which 
cannot make starch for themselves) and in them is again 
laid down in the form of solid starch grains, which are 
subsequently dissolved and used for the growth of the ger- 
minating seed or potato. Reasons have already been given 
(p. 423) for believing that the carbohydrate leaving the 
liver is not oxidized in the blood, but first after it has passed 
out of that into a living tissue. Among these the muscles.at 
Teast seem to get some, since a frosh muscle always contains 
glycogen, and even in normal amount when an animal is 
starved for some time; the muscle-fibres then, so to speak, 
calling on the balance with their banker (the liver) so long 
ag there is any. When a muscle contracts this glycogen 
disappears and some glucose appears, but not an amount 
equivalent to the glycogen used up; so that the working 
musele would appear, probably for its repair after each con- 
traction (see p. 431), to utilize this substance. 

How it is that the glycogen, which is so rapidly con- 
verted into grape sugar by the liver ferment after death, 
escapes such rapid conversion during life has not been 
satisfactorily answered. ‘Two possible reasons readily sug- 
gest themselves; the liver ferment may be only produced 
by dying hepatic cells; or the glycogen in the living cell 
may not exist free, but combined with other portions of the 
cell substance so as to be protected; while, after death, 
post-mortem changes may rapidly liberate it in a condition 
to be acted upon by the ferment. 

Diabetes. The study of this disease throws some light 
upon the history of glycogen. Two distinot varieties of it 








42 THE HUMAN BODY. 


are known; one in which sugar appears in the urine only 
when the patient takes carbohydrate foods; the other in 
which it is still exereted when he takes no such foods, and 
must therefore form sugar in his Body from substances not at 
all chemically allied to it. The most probable source of the 
sugar in the latter case is proteids; since some glycogen is 
found in the livers of animals fed on proteids only, while fate 
alone give none of it. In some complex way the proteid mole- 
cule would appear to split up in the liver intoa highly nitro- 
genized part (urea or an antecedent of urea) and # non- 
azotized part, glycogen. On this view the more severe form 
of diabetes would be due to an increased activity of a normal 
proteid-decomposing function of the hepatic cells; and 
sometimes the urea and sugar in the urine of diabetics 
rise and fall together, thus seeming to indicate a com- 
munity of origin. Diabetes dependent on carbohydrate 
food might be produced in several ways. The liver-cells 
might cease to stop the sugar and, letting it all pass on into 
the general circulation, suffer it to rise to such a percentage 
in the blood after a meal, that it attained the proportion in 
which the kidneys pass it out; or the tissues might cease to 
use their natural amount of sugar, and this, sent on steadily 
out of the liver, at last rise in the blood to the point of ex- 
erection. Or the liver might transform (into glucose) and 
pass on its glycogen faster than the other tissues used it, 
and so diabetes might arise; but this would only be tem- 
porary, lasting until the liver stock was used up by the 
rapid conversion. Artificially we can, in fact, produce 
diabetes in several of these ways; curari poisoning, for ex- 
ample, paralyzing the motor nerves, makes the skeletal 
muscles lie completely at rest, and so diminishes the glyeo- 
gen consumption of the Body and produces diabetes, Car- 
bon monoxide poisoning produces diabetes also, presumably 
by checking bodily oxidation. Finally, pricking a certain 
spot in the medulla oblongate causes a temporary diabetes, 

This may be due to the fact that the operation injures 
that part of the vaso-motor centre which controls the mus- 
cular coat of the hepatic artery: this artery, then dilating, 
carries so much blood through the liver that an excess of 


FATS, 


glycogen is turned into glucosein agiven time, and carried off 
by the hepatic yeins. If the splanchnic nerves be cut the 
whole arteries of the abdominal viscera dilate and no diabetes 
follows, because 30 many vessels being dilated a great par- 
of the blood of the Body accumulates in them, and there is 
no noticeably increased flow through the liver. Others, 
however, maintain that the “‘pigdre” diabetes (as that due 
to pricking the medulla is called) is due to irritation of 
trophic nerve-fibres originating there, and governing the 
rate at which the liver-cells produce glycogen or convert it 
into glucose. This latter view, though perhaps the less 
commonly accepted, is probably the more correct, The 
hepatic cells do not merely hold back glucose carried 
through the liver so that it is there to be washed out by a 
greater blood-flow, but they feed on glucose and proteids 
and make glycogen; and this is later conyerted into glucose 
and carried off. Glycogen is thus comparable to the zymo- 
gen of the pancreas and other glands (Chap. XVIIL); and 
the transformation of such bodios into the specific clement 
of a secretion we have already seen to be directly under the 
contro] of the nervous system, and almost entirely or quite 
independent of the blood-flow. 

‘The History of Fats. While glycogen forms a reserve 
store of material that is subject to rapid alterations, deter- 
mined by meal-times, the fats are much more stable; *their 
periods of fluctuation are regulated by days, weeks, or 
months of good or bad nutrition, and during starvation they 
are not so readily, or at least so rapidly, culled upon as the 
hepatic glycogen. If we carry on the simile by which we 
compared the reserve in each cell to pocket-money (p. 31), 
the glycogen would answer somewhat to a balance on the 
right side with a man’s banker; while the fat would 
represent aasets or securities not go rapidly realizable; as 
capital in business, or the cargoes afloat in the argosies of 
Antonio, the ‘ Merchant of Venice.” Fat, in fact, is 
slowly laid down in fat-cells and surrounded in these by a 
cell-wall, and, being itself insoluble in blood plasma or 
lymph, it must undergo chemical changes, which no doubt 














= 3 





444 THE HUMAN BODY. 


require some time, before it can be taken into the blood 
and carried off to other parts. 

When adipose tissue is developing it is seen that undif- 
ferentiuted cells in the connective tissues (especially areolar) 
show minute oil-drops in their protoplasms. These increase 
in size and, ultimately, fuse together and form one 
vil-droplet, while most of the original protoplasm dis- 
appears. 

The oily matter would thus seem due to a chemical 
metamorphosis of the cell protoplasm, during which it gives 
rise to a non-azotized fatty residue which remains 
and a highly nitrogenous part which is carried off. In 
many parts of the Body protoplasmic masses are subject to 
a similar but less complete metamorphosis; fatty degenera- 
tion of the heart, for example, is a more or less extensive 
replacement of the proper substance of its musoular fibres 
by fat-droplets; and the cream of milk and the oily matter 
of the sebaceous secretion are due to a similar fatty 
degeneration in gland-cells. Moreover, careful feeding ex 
periments undoubtedly show that fat can come from pro- 
teids; when an animal is very richly supplied with these 
all the nitrogen taken in them 1 Teappears in its 
but all the carbon does not; it is in part stored in the Body: 
and, since such feeding produces but little glycogen, this 
carb can only be stored as fat. 

While there is, then, no doubt that some fat may have a 
proteid origin, it is not certain that all has such. During 
digestion a great deal of fat is ordinarily absorbed, in # 
chomically unchanged state, from the alimentary canal; it 
is merely emulsified and carried off in minute drops by the 
chyle to be poured into the blood: and this fat might be 
directly deposited, as such, in adipose tissue. ‘There are, 
however, good reasons for supposing that all the fat in the 
Body is manufactured. The fat of aman, of adog, and ofa 
cut varies in the proportions of palmatin, stearin, margarin, 
and olein in it; and varies in just the same way if all be fed on 
the sume kind of food, which could not be the case if the 
fat caten were simply deposited unchanged. Moreover, if 
an animal be fed on a diet containing one kind of fat only, 





ORIGIN OF FATS. 


say olein, but a very slightly increased percentage of that 
particular fatty substance is found in its adipose tissue, 
which goes to show that if fats come from fats eaten, these 
latter are first pulled to bits by the living cells and built up 
again into the forms normal to the animal; so that, even with 
fatty food, the fats stored up seem to be in most part 
manufactured in the Body. 

In still another way itis proved that fats can be constructed 
in the Body. In animals fed for slaughter, the total fat 
stored up in them during the process is greatly in excess 
of that taken with their food during the same time. For ex- 
ample, a fattening pig may store up nearly five hundred 
parts of fat for every hundred in its food, and this fat 
must be made from proteids or carbohydrates, Whether it 
can come from the latter is still perhaps an open question; 
for, while all fattening foods are rich in starch or similar 
bodies, there are considerable chemical difficulties in sup- 
posing an origin of fats from such; and it is on the whole 
more probable that they simply act by sparing from tse 
fats simultaneously formed or stored in the body, and 
which would have otherwise been called upon. They make 
glycogen, and this shelters the fats. Licbig, indeed, in a very 
celebrated discussion, maintained that fats were formed 
trom carbohydrates, He showed that « cow gave out more 
butter in its milk than it received fats in its food; and 
Huber, the blind naturalist, showed that bees still made 
wax (a fatty body) for a time when fed on pure sugar; and 
indefinitely when fed on honey. Consequently, for a long 
time, an origin of fats from carbohydrates wag supposed to 
be proved; but their possible origin from proteids (a possi- 
bility now shown to be a certainty) was neglected, and the 
validity of the above proofs of their carbohydrate origin is 
thusupset, The cow may have made its butter from proteida; 
the bees, fed on sugar, their wax for a time from proteids 
in their bodies already; and, indefinitely, when fed on honey, 
from the protoids in that substance. Moreover, animals 
(ducks) fed on abundant rice, which contains much carbo- 
hydrate but very little proteid or fat, remain lean; while if 
some fat be added they lay up fut, 








446 THE HUMAN BODY. 


Persons who fatten cattle for the butcher find that the 
foods useful for the purpose all contain proteids, carboby- 
drates, and fats, and that rapid fattening is only obtained 
with foods containing a good deal of fat; as oileake, milk, 
or Indian corn. ‘Taking all the facts into account we shall 
probably not be wrong in concluding that nearly all the 
bodily fat is manufactured either from fats or proteids; 
from fats easier than from anything else, but when much 
proteid is eaten some iz made from it also. Carbohydrates 
alone do not fatten; the animal body cannot make its pal- 
matin, etc.,outof them. Nevertheless they are, indirectly, 
important fattening foods when given with others, since, 
being oxidized instead of it, they protect the fat formed. 

Dietetics, That ‘‘one man’s meat may be another 
man’s poison” is a familiar saying, and one that, no doubt, 
expresses a certain amount of truth; but the difference 
probably depends on the varying digestive powers of indi- 
viduals rather than on peculiarities in their laws of cell 
nutrition: all need pretty much the same amount of pro- 
teids, fats, and carbohydrates for each kilogram of body 
weight; but all cannot digest the same varieties of them 
equally well: while many foods have peculiar, almost 
poisonous, effects on some persons. A good many people 
are made ill by mutton, which the majority digest better 
than beef. 

The proper dict, too, will necessarily vary, at least as to 
amount,with the work done; whether it should vary in kind 
with the nature of the work is not so certain. Provided a 
man gots enough proteids to balance those lost in the wear and 
tear of his tissues, it probably matters little whether he gots 
for oxidation and the liberation of energy either fats or car- 
bohydrates, or even excess of proteids themselves; any one of 
the three will allow him to work either his brain or his muscles, 
and to maintain his temperature. Proteids, however, are 
wasteful foods for mere energy-yielding purposes: in the first 
place, they are more costly than the others; secondly, they 
are incompletely oxidized in the Body; and, thirdly, it is 
probably more laborious to the system to get rid of urea than 
of the carbon dioxide and water, which alone are yielded by 





DIETETIOS. a7 


the oxidation of fats and carbohydrates. Between fats and 
carbohydrates similar considerations lead to a use of the latter 
when practicable: starch 1s more easily utilized in the Body 
than fats, as shown by the manner in which it protects the 
latter from oxidation; and a given weight of starch fully 
oxidized in the Body will liberate one and a half times as much 
energy as the same amount of butter, while it costs consider- 
ably less than half the money. Probably, too, starch is 
more easily digested than fata; at least by many people: 
children especially are apt to be fond of starchy or sac- 
charine foods and to loathe fats; and the appetite in such 
cases is a good guide. As a race, too, the American people 
differ markedly from the English in their love of sweet 
foods of all kinds; whether this is correlated with their 
characteristic activity, calling for some food that ean be 
rapidly used, is an interesting question, to which, however, 
it would be rash to give at present an affirmative answer. 
It is clear, therefore, that no general rules for every one’s 
diet can be laid down; but still on broad principles the 
best diet would be that which contained just the amount of 
proteid necessary for tissue repair, and so much carbo- 
hydrates as could be well digested, the balance needed, if 
any, being made up by fats, Such a food would be the 
cheapest; that is the supplying of it would call for less of 
the time and energy of the nation using it, and leave more 
work to spare for other pursuits than food production— 
for all the arts which make life agreeable and worth living, 
and which elevate civilized man above the merely material 
life of the savage whose time ts devoted to catching and eat- 
ing. We have high authority for saying that man does 
not live by bread alone; in other words his highest develop- 
ment 1s impossible when he is totally absorbed in ‘* keeping 
body and soul together,” and the more labor that can be 
spared from getting enough food the better chance has he, 
if he use his leisure rightly, of becoming a more worthy 
man. While there is, thus, a theoretically best diet, it is 
neverthelesa impossible to say what that is for each indi- 
vidual; but what the general experience is may be approxi- 
mately gathered by taking an average of the dictaries of a 





number of public institutions in which the health of many 
people ix maintained as economically as possible. Such an 
examination made by Moleschott, gives us as its result adiet 


People in easy circumstances take as a rule more proteids 
and fats and less amyloids; and this selection, when a 
choice is possible, probably indicates that such a diet is the 
better one: the proteids in the above table seem especially 
deficient. 





CHAPTER XXIX. 


THE PRODUCTION AND REGULATION OF THE 
HEAT OF THE BODY. 


Cold- and Warm-Blooded Animals. All animals, so 
long as they are alive, are the seat of chemical changes by 
which heat is liberated; hence all tend to besomewhat warmer 
than their ordinary surroundings, though the difference may 
not be noticeable unless the heat production is considerable. 
A frog or a fish is a little hotter than the air or water in 
which it lives, but not much; the little heat that it pro- 
daces is lost, by radiation or conduction, almost at once. 
Hence such animals have no proper temperaturo of their 
own; on a warm day they are warm, on a cold day cold, 
and are accordingly known as changeable-temperatured 

thermous) or,in ordinary language, “‘ cold-blooded” 
animals, Man and other mammals, aswell as birds, on the 
contrary, are the seat of very active chemical changes by 
which mach heat is produced, and s0 maintain a tolerably 
uniform temperature of their own, much us a fire docs 
whether it be burning in a warm ora cold room; the heat 
production at any given time balancing the loss a nor- 
mal body temperature is maintained, and usually one con- 


live; ete animals are therefore known as animals of con- 
stant temperature (homo-thermous), or more commonly 
“warm-blooded” animals, ‘The latter name, however, does 
not properly express the facts; a lizard basking in the sun 
summer's day may be nearly as hot as a man 

i8; but on the cold day tho lizard becomes cold, 

while the average temperature of the healthy Human Body 








450 THE HUMAN BODY, 


is, within a degree, the same in winter or summer; within 
the arctic circle or on the equator, 

Moderate warmth accelerates protoplasmic activity; com- 
pare a frog dormant in the winter with the same animal 
active in the warm months: what is trae of the whole 
frog is true of each of its living cells. Its muscles contract 
more rapidly when warmed, and the white corpuscles of its 
blood when heated up to the temperature of the Human 
Body are seen (with the microscope) to exhibit much more 
active amm@boid movements than they do at the tempera- 
tnre of frog’s blood. In summer a frog or other eold- 
blooded animal uses much more oxygen and evolves much 
more carbon dioxide than in winter, as shown not only by 
direct measurements of its gaseous exchanges, but by the 
fact that in winter a frog can live a long time after its 
lungs have been removed (being able to breathe sufficiently 
through its moist skin), while in warm weather it dies of 
asphyxia very soon after the same loss. The warmer 
weather puts its tissues in a more active state; and so the 
amount of work the animal dovs, and therefore the amount 
of oxygen it needs, depend to a great extent upon the tem- 
perature of the medium in which it is living. With the 
warm-blooded animal the reverse is the case. It always 
keeps up ita temperature to that at which its tissues live 
best, and accordingly in cold weather uses more oxygen and 
sets free more carbon dioxide because it needs a more active 
internal combustion to compensate for ite greater loss of 
heat to the exterior. In fact the living tissues of a min 
may be compared to hothouse plants, living in an artifiel- 
ally maintained temperature; but they differ from the 
plunts in the fact that they themselves are the seats of the 
combustions by which the temperature is kept up. Sinee, 
within wide limits, the Human Body retains the eame tem- 
perature no matter whether it be in cold or warm surround- 
ings, it isclear that it must possess an accurate arrangement 
for heat regulation; either by controlling the production of 
heat in it, or the loss of heat from it, or both. 

The Temperature of the Body. ‘The parts of the Body 
are all either in contact with one another directly or, if 


hell a =) 


SOURCES OF BODILY HEAT. 451 


not, at least indirectly through the blood, which, flowing 
from part to part, carries heat from warmer to colder 
regions. Thus, although at one time one group of muscles 
may especially work, liberating hest, and at other times 
another, or the muscles may be at rest and the glands the 
seat of active oxidation, the temperature of the whole Body 
is kept pretty much the same. * The skin, however, which 
is in direct contact with external bodies, usually colder than. 
itself, is cooler than the internal organs; its temperature in 
health is from 36° to 37° O. (96.8-98.5° F.), being warmer 
in more protected parts, as the hollow of the armpit. In 
internal organs, as the liver and brain, the temperature is 
higher; about 42° 0. (107° F.) in health. In the lungs, 
though there is a certain quantity of heat liberated when 
oxygen combines with hemoglobin, this is more than 
counterbalanced by loss of the heat carried out by the ex- 
pired air, and that used up in evaporating the water carried 
ont in the breath; so blood returned to the heart by the 
pulmonary veins is slightly colder than that carried from 
the right side of the heart to the lungs. 

Tho Sourcos of Animal Heat. These are two-fold; 
direct and indirect. Heat is directly produced wherever 
oxidation is taking place; so that all the living tissnes at 
rest produce heat as the result of the chemical changes sup- 
plying them with energy for the maintenance of their 
vitality; and whenever an organ is active and its chemical 
metamorphoses are increased it becomes hotter: a secreting 
gland or a contracting muscle is warmer than a resting one. 
Indirectly, heat is developed by the transformation of other 
forms of energy; mainly mechanical work, but, to a less 
extent, also of electricity. All movements of parts of the 
Body which do not move it in space or move external objects, 
are transformed into heat within it; and the energy they 
represent is Jost in that form. Every cardiac contraction 
sets the blood in movement, and this motion is for the most 
part turned into heat within the Body by friction within 
the blood-vessels. The same transformation of energy occurs 
with respect to the movements of the alimentary canal, ex- 
cept in so far as they expel matters from the Body; and 








452 THE HUMAN BODY. 


every muscle in eontracting has part of the mechanical 
energy expended by it turned into heat by friction against 
neighboring parts. Similarly the movements of cilia and 
of ameboid cells are for the most part converted in the 
Body into heat. The muscles and nerves are also the seats 
of manifestations of electricity, which, though small in 
amount, for the most partdo not leave the Body in that 
form but are first converted into heat. A certain amount 
of heat is also carried into the Body with hot foods and 
drinks. 

The Energy Lost by the Body in Twenty-four Hours. 
Practically speaking, the Body only loses energy in two 
forms; as heat and mechanical work: by applying condue- 
tors to different parts of its surface small amounts of elec- 
tricity can be carried off, but the amount is quite trivial in 
comparison with the total daily energy expenditure. Dur- 
ing complete rest, that is when no more work ix done than 
that necessary for the maintenance of life, nearly all the 
loss takes the form of heat. The absolute amount of thia 
will vary with the surrounding temperature and other con- 
ditions, but « crage a man loses, during a day of 
rest, 2700 cal that is enough to raise 2700 kilograms 

f 0 er from 0° to 1° ©. (from 32° to 33.8° F.); 
» this amount of heat would boil 27 kilos 

‘This does not quite represent 

y in that time: since a small 

sal work in moving the clothes 

movements, and even by the 

systole pushes ont the 

‘ings in contact with it. 

much more energy; 





BODILY ENERGY LOST PER DAY, 453 


Day of Beat, Day of Work. 


fone ee, ee 
Rest hire SleepShra’ HestShra WorkShra SleepShre 
Heatanierouler-t smd = see 2400.6 am, 


arma (TSS aia) ems (HE ) 


ies) produced. . 


The mechanical work done on the working day, repre- 
sented in addition an expenditure of energy of 213,344 
kilogrammeters, which is equal to 502 calories. Of the ex- 
cess heat in the working day, part is directly produced by 
the increased chemical changes in the quicker working heart 
and respiratory muscles, and the other muscles set at work; 
while part is indirectly due to heat arising from increased 
friction in the blood-vessels as the blood is driven faster 
around them, and to friction of the various muscles used. 
‘The average cardiac work in twenty-four hours is about 
60,000 kilogrammeters; that of the respiratory muscles 
about 14,000 ; and since nearly all of both is turned finally 
into heat within the Body, we have 74,000 kilogrammeters 
of energy answering to about 174 calories (6786 Fab.-lb. 
units) indirectly produced in the resting Body daily from 
these sources, 

Of 100 parts of heat lost from the resting Body, about 
73 ave carried off in radiation or conduction from the skin. 
14.5 are carried off in evaporation from the skin. 

we 4 “ “ « Tongs, 
Oe ee “ expired air. 
Lar eas ** in the excretions. 


In a day of average work, of every 100 parts of energy lost 
in any form from the Body— 
1-2 go as heat in the excreta, 
‘3-4 in heating the expired air. 
20-30 in evaporating water from the lungs and skin. 
60-75 in heav radiated or conducted from the surfaces and 
in external mechanical work, 


‘The Superiority of the Body as a Working Machine. 
During eight hours of work, we find (table at top of page) 
the Body loses 2169.6 calories of energy us heat; and can do 





it ing organ is the skin: under ordi- 
ces nearly 90 per cent ofthe total bea givin 


‘wear more in cold and less in 
s being, of course, not to 


ch the rate at which the heat 





TEMPERATURE.REGULATION IN TUE BODY. 455 


quickened respirations, too, increase the evaporation of water 
in the lungs and, thus, the loss of heat. 

3. Warmth directly dilates the skin-vessels and cold con- 
tracts them. In a warm room the vessels on the surface 
dilate as shown by its redness, while in a cold atmosphere 
they contract and the skin becomes pale. But the more 
blood that flows through the skin the greater will be the 
heat lost from the surface—and vice versa, 

4. Heat induces sweating and cold checks it; the heat 
appears to act, partly, reflexly in exciting the sweat-centres 
from which the secretory nerves for the sudoriparous glands 
arise, and, partly, directly on those centres, which are thrown 
into activity, at least in health, as soon as the temperature of 
the blood is raised. In fever of course we may have a high 
temperature with a dry non-sweating skin. The more sweat 
there is poured ont, the more heat is used up in evaporating 
it and the more the Body is cooled. 

5. Our sensations induce us to add to or diminish the 
heat in the Body according to circumstances; as by cold or 
warm baths, and iced or hot drinks. 

As regards temperature-regulation by modifying the rate 
of heat production in the Body the following points may be 
noted; on the whole such regulation is far less important 
than that brought about by changes in the rate of loss, since 
the necessary vital work of the Body always necessitates 
the continuance of oxidative processes which liberate a tol- 
erably large quantity of heat, The Body cannot therefore 
be cooled by diminishing such oxidations ; nor on the other 
hand can it be safely warmed by largely i increasing them. 
Still, within certain limits, the heat ete may be con- 
trolled in several ways— 

1. Cold mereases hunger; and increased ingestion of food 
increases bodily oxidation as shown by the greater amount 
of carbon di excreted in the hours succeeding a meal. 
‘This increase is probably due to the activity into which the 
digestive organs are thrown. 

2. Cold inclines to voluntary exercise; warmth to muscu- 
lar idleness; and the more the muscles are worked the more 
heat is prodnced in the Body. 





456 THE HUMAN BODY. 


%. Cold tends to produce involuntary muscular move- 
ments, and so increused heat production; as chattering 
of the teeth and shivering. 

4. Cold applied to the skin increases the bodily chemical 
metamorphoses and so heat production. At least the tem- 
perature in the armpit rises at first on entering acold bath, 
though the heat carried off from the surface soon overbalances 
its increased production. The phenomenon may, however, 
be explained in another way, the rise being attributed to a 
sudden diminution of loss from more exposed parts of the 
skin, dependent on contraction of the cutaneous arteries, 
In some cases, however, the temporary rise is accom 
by an increased exeretion of carbon dioxide, which would 
indicate that the surface cooling does really increase the 
oxidations of the Body. 

5. Certain drugs, a8 salicylic acid, and perhaps quinine, 
diminish the heat production of the Body. Their mode of 
action is still obscure. 

On the whole, however, the direct heat-regulating me- 
chanisms of the Human Body itself are not very efficient, 
especially as protections against excessive cooling. Man 
needs to supplement them by the use of clothing, fuel, and 
exercise. 

Local Temperatures. Although, by the means above 
described, a wonderfully uniform bodily temperature is 
maintained, and by the circulating blood all parts are kept 
at nearly the same warmth, variations in both respects do 
occur. The arrangements for equalization are not by any 
means fully efficient. External parts, as the skin, the lungs 
(which are really external in the sense of being in contact 
with the air), the mouth, and the nose chambers, are always 
cooler than internal; and even all parts of the skin have 
not the same temperature, such hollows as the armpit being 
warmer than more exposed regions. On the other hand, 
a secreting gland or a working muscle becomes warmer, for 
the time, than the rest of the Body, because more heat is 
liberated in it than is carried off by the blood flowing 
through. In such organs the venons blood leaving is warmer 
than the arterial coming to them; while the reverse is the 


ull 








THERMIO NERVES. 457 


case with parts, like the skin, in which the blood is cooled, 
An organ colder than the blood is of course warmed by 
‘an increase in its circulation, as seen in the local rise of tem- 
perature in the skin of the face in blushing. 

'Thermic Nerves. All nerves, such as motor or secre- 
tory, which can throw working tissues into activity are in 
a-certain sense thermic nerves: since they excite increased 
oxidation and heat production in the parts under their con- 
trol. A true, purely thermic nerve would be one which 
increased the heat production in a tissue without otherwise 
throwing it into activity; and whether such exist is still 
undecided. Certain phenomena of disease, however, seem 
to render their existence probable. If we return for a 
moment to our former comparison of the working Body to 
a steam-engine, such nerves might be regarded as agencies 
increasing its rate of rusting without setting it at work. 
‘The oxidation of the iron would develop some heat, but by 
processes useless to the steam-engine, although such are, 
in moderation, essential to living cells; the vitality of 
these even when at rest, seems to necessitate a constant, 
if small, breaking down of its substance. In an ammboid 
cell no doubt such processes occur quite independently of 
the nervous system; but in more differentiated tissues they 
may be controlled by it, Just as a muscle does not nor- 
mally contract unless excited through its nerve, although 
a white blood corpuscle does, so may the natural nutritive 
processes of the muscle-fibre in its resting condition be de- 
pendent on the nerves going to it. If these be abnormally 
excited the muscle will break down its protoplasm faster 
than it constructs it, and consequently waste; at the 
same time the increased chemical degradation of its sub- 
stance will elevate its temperature. Febrile conditions, in 
which many tissues waste, without any unusual manifesta- 
tion of their normal physiological activity, would thus be 
readily accounted for as due to superexcitation of the 
thermic nerves. Moreover, it is found that lesions or sec- 
tions of the spinal cord are followed by a rise in the tem- 
perature of those parts of the Body supplied with nerves 
arising below the diseased or divided portion. Now 





4358 THE HUMAN BODY. 

division of the spinal cord in two ways tends to lower the 
temperature of parts below the injury: in the first 

the muscles are paralyzed and soa great source of heat is 
ent off; and in the second, the vaso-motor nerves traveling 
down from the medullary centre are eut, and hence the 
skin arteries behind the section dilate and carry more blood 
to the surface to be cooled, To explain the rise of tem- 
perature it has therefore been concluded that there are 
true thermic centres in the spinal cord, which centres, like 
others in that organ (Chap, XXXV.), are held in check or 
inhibited by brain-centres; when the controlling influence 
of the latter is removed the former may excite excessive oxida 
tions in the tissues to which they are distributed, and so 
produce the rise of temperature. The proof, however, is 
not complete; for the raised temperature may, after all, be 
due merely to an excessive supply of blood, warmed else- 
where in the Body, to the dilated skin-veasela, 

Clothing. ‘To man, as social animal, endowed with 
moral feelings, clothing has certain uses in the interests 
of morality; but for euch purposes the amount necessary is 
not great ¢ find in many tribes living in warm climates, 
Except in Geypel Tegions, however, clothing has in addi- 

I ‘ical use in regulating the bodily 
While the majority of other warm-blooded 
their own, formed of hairs or feathers, 
dy his capillary coating is merely rudi- 
plogical importance; and so 

artificial garments, which 

to utilize also for purposes of 

+, we must confine ourselves to 

t of view. In civilized 

corer most of his Body 

ion is what is the best 

‘ourse, with the climatic 

Tn warm regions, 

low free radiation or 

cold it should ie 





CLOTHING. 459 


of the Body be exposed so that currents of air can freely 
traverse it much more heat will be carried off (under 
those usual conditions in which the air is cooler than the 
kin) than if a stationary layer of air be maintained in con- 
tact with the surface. As every one knows, a “draught” 
cools much faster than air of the same temperature not in 
motion. All clothing, therefore, tends to keep up the 
temperature of the Body by checking the renewal of the 
layer of air in contact with it. Apart from this, however, 
clothes fall into two great groups; those which are good, and 
those which are bad, conductors of heat. The former allow 
changes in the external temperature to cool or heat rapidly 
the air stratum in actual contact with the Body, while the 
latter only permit these changes to act more slowly. Of 
the materials used for clothes, linen is a good conductor; 
calico not quite so good; and silk, wool, and fur are bad 
conductors. 

Whenever the surface of the Body is suddenly chilled 
the skin-vestels are contracted and those of internal 
parts reflexly dilated; hence internal organs tend to 
become congested, a condition which readily passes into the 
‘diseased state known as inflammation. When hot, therefore, 
the most unadvisable thing to do, is to sit in a dranght, 
throw off the clothing, or in other ways to strive to get sud- 
denly cooled. Moreoyer, while in the American summer it 
is tolerably safe to wear good-conducting garments, and few 
people take cold then, this is by no means safe in the 
spring or autumn, when the temperature of the air is apt 
to vary considerably within the course of w day. A person 
going out, clad only for a warm morning, may have to re- 
turnin a vory much colder evening; and if his clothes be not 
such as to prevent a sudden surface chill, will get off lightly 
if he only “take” one of the colds so prevalent at those 
seasons. Inthe great majority of cases, no doubt, he suffers 
nothing worse, but many persons, especially of the female 
sex, often acquire far more serious diseases. When sudden 
changes of temperature are at all probable, even if the pro- 
yailing weather be warm, the trunk of the Body should 
be always protected by some tolerably close-fitting garment 





460 THE HUMAN BODY. 


of non-conducting material. Those whose skins are irri- 
tated by anything but linen should wear immediately ont- 
side the under-garments a jacket of silken or woolen 
material. In midwinter comparatively few people take 
cold, because all then wear thick and nonconducting cloth- 
ing of some kind. 





CHAPTER XXX. 
SENSATION AND SENSE-ORGANS. 


The Subjective Punctions of the Nervous System. 
Changes in many parts of our Bodies are accompanied or 
followed by those states of consciousness which we call sen- 
sations. All such sensitive parts are in connection, direct 
or indirect, with the brain, by certain afferent nerve-fibres 
called sensory. Since all feeling is lost in any region of the 
Body when this connecting path is severed, it is clear that 


all sensations, whatever their primary exciting cause, are 
finally dependent on conditions of the central nervous sys- 
tem. Hitherto we have studied this as its activities aro 
revealed through movements which it excites or prevents; 
we haye seen it, directly or reflexly, cause muscles to con- 
tract, glands to secrete, or the pulsations of the heart to 
cease; we have viewed it objectively, as a motion-reguluting 
apparatus, Now we have to turn to another side and con- 
sider it (or parts of it) as influencing the states of conscious- 
ness of its possessor: this study of the subjective activities 
of the nervous system is one of much greater difficulty. 
It may be objected that considerations concerning states 
f feeling have no proper place in a treatise on Anatomy 
and Physiology; that, since we cannot form the beginning 
of a conception how a certain state of the nervous system 
ising the feeling redness, another the fecling blueness, and 
rd the emotion anger, all examination of mental phe- 
should be excluded from the scienoes dealing with 
the stracture and properties of living things. But, although 
we cannot imagine how a nervous state (newrosis) gives rise 
to a conscious state (psychosis), we do know this, that dis- 
tinct phenomena of consciousness never come under our 








462 THE HUMAN BODY. 


observation apart from s nervous system, and so are pre- 
sumably, in some way, endowments of it; we are, 

justified in calling them properties of the nervous system; 
and their examination, especially with respect to what 
nerve-parts are concerued with different mental states, and 
what changes in the former are associated with given phe- 
nomena in the latter, forms properly a part of 

Whether masses of protoplasm, before the differentiation of 
definite nerve-tissues, possess some ill-defined sort of con- 
sciousness, as they posséss an indefinite contractility before 
they have been modified into muscular fibres, may for the 
present be left undecided: though those who seat the doc. 
trine of eyolution will be inclined to assent to the i 

While, however, the Physiologist has a right to be heard 
on questions relating to our mental faculties, it is never- 
theless true that many laws of thought have been esta- 
blished, concerning which our present knowledge of the 
luws of the nervous system gives us no cluo; the seience of 
Psychology has thus a well-founded claim to an independent 
existence. But, in go fur as its results are confined merely 
to the successions and connections of mental states, aa estab- 
lished by observation, they are merely descriptions, and not 
explanations in a sciéntific sense: we know that so many 
mental phenomena have necessary material antecedents and 
concomitants in nervous changes, that we are justified ix 
believing that all have such, and in continuing to seek for 
them. We do not know at all how an electric current seal 
round a bar of soft iron makes it magnetic; we only know 
that the one change is uccompanied by the other; but we 
say we have explained the magnetism of a piece of iron if 
we have found an electric current circulating around it, 
Similarly, we do not know how 4 nervous change causes & 
mental state, but we have not explained the mental state 
until we have found the nervous state associated with it 
and how that nervous state was produced. 

As yet it is only with respect to some of the simplest 
wtates of consciousness that we know much of the necessary 
physiological antecedents, and among these our sensations 
ure the best investigated, As regards such mental pheno- 


a 


SENSATION AND ORGANS OF SPECIAL SENSE. 463 


mena us the Association of Ideas, and Memory, physio- 
logy can give us some light; but so far as others, such aa the 
Willand the Emotions, are concerned, it has at present little 
to offer. The phenomena of Sensation, therefore, occupy 
at present a much larger portion of physiological works 
than all other mental facts put together. 

Common Sensation and Organs of Special Senso. A 
sensory nerve is one which, when stimulated, arouses, or 
may arouse, a sensation in its possessor, The stimulant is 
in all cases some form of motion, molar (¢.g. mechanical 
pressure) or molecular (as ethereal vibrations or chemical 
changes). Since all our nerves lie within our Bodies as 
circumscribed by the skin, and are excited within them, one 
might, @ priori be inclined to suppose that the cause of all 
sensations would appear to be within our Bodies themselves; 
that the thing fel? would be a modified portion of the fesler. 
‘This is the case with regard to many sensations; a head- 
ache, toothache, or earache gives us no idea of any external 
object; it merely suggests to euch of us a particular 
state of a sensitive portion of myself. As regards many 
sensations, however, this is not 80; they suggest to ux ex- 
ternal causes, to properties of which and not to states of our 
Bodies, weaseribe them; and so they lead us to the conception 
of an external universe. A knife laid on the skin produces 
changes in it which lead us to think not of a state of our 
skin, but of states of some object outside the skin; we 
believe we feela cold heavy hard thing in contact with it. 
Nevertheless we have no sensory nerves going into the knife 
and informing as directly of its condition; what we really 
feel are the modifications of our Body produced by it, 
although we irresistibly think of them as properties of the 
knife—of some object that is no part of our Body, and not as 
states of the latter itself. Let now the knife cut throngh 
the skin; we feel no more knife, but experience pain, 
which we think of as a condition of ourselves. We do not 
say the knife is painful, but that our finger is, and yet we 
have, go far us sensation goes, as much reason to call the 
knife painful as cold. Applied one way it produced local 
changes arousing a sensation of cold, and in another local 








QUALITIES OF SENSATIONS. 465 


skin with & given sensation, and whenever afterwards the 
nerve-flbres coming from the finger are stimulated, no mat- 
ter where, we ascribe the origin of the sensation to some- 
thing aeting on the finger-tip. 

The Differences between Sensations. In both groups 
of sensations, those derived through orguns of special 
sense and those due to organs of common sensation, we dis- 
tinguish kinds which are absolutely distinet for our con- 
sciousness, and not comparable mentally. We can never 
get confused between a sight, a sound, and a touch, nor be- 
tween pain, hunger, and nausea; nor can we compare them 
with one another; each is sué generis. The fundamental 
difference which thus separates one sensation from another 
is its modality. Sensations of the same modality may differ; 
but they shade imperceptibly into one another, and are com- 
parable between themselves in two ways, First, as regards 
quality; while a high and a low pitched note are both 
auditory sensations, they are nevertheless different aud yet 
intelligibly comparable; and so are blue and red objects. 
In the second place, sensations of the same modality aro 
distinguishable and comparable as to amount or intensity: 
we readily recognize and compare a loud and a weak sound 
of the same pitch; a bright and feeble light of the same 
color; an acute and a slight pain of the same general char- 
acter, Our sensations thus differ in the three aspects of 
modality, quality within the same modality, and intensity. 
Certain sensations also differ in what is known as the 
*‘local sign,” a difference by which we tell a touch on one 
part of the skin from a similar touch on another; or an ob- 
ject exciting one part of the eye from an object like it, but 
in a different location in space and exciting another part of 
the visual surface. 

As regards modality, we commonly distinguish five 
senses, those of sight, sound, touch, taste, and amell; it is 
doubtful whether temperature should not be added. The 
varieties of common sensation are alsoseveral; for example, 
pain, hunger, satiety, thirst, nansea, malaise, bion-étre (fecl- 
ing “ good”), fatigue. The mtscular sense stands on the 
intermediate line between special and common sensations; 





movement by external objects, on the other, In fact, we 
cannot draw a sharp line between the special senses and 
common sensations; all the Body, we conclude from ob- 
servations on the lower animals, is, at an early stage of its 
development, sensitive; very soon its cells separate them- 
selves into an outer layer oxposed to the action of external 
forces and an inner layer protected from them: and some 
of the former cells become especially sensitive. From them, 
as development proceeds, some are separated and bedied! Los 


‘others to slight che par testo 
7 8 chemical cl (in 
and others (in the skin) to variations 
nature, 

are thus modifications of one common 





STRUCTURE OF SENSE-ORGANS. 467 


end organs in the eye, others end organs in the ear, and so 
on; while others, less changed, remain in the skin as organs 
of touch and temperature; and so, from a general exterior 
surface responding equally readily to many external natural 
forces, we get a surface modified so that its yarions parts 
respond with different degrees of readiness to different ¢x- 
ternal forces; and these modified parts constitute the essen- 
tial portions of our organs of special sense. Every sense 
organ thus comes to have a special relationship to some one 
natural force or form of energy—is a specially irritable 
mechanism by which such a force is enabled to excite sen- 
sory nerves; and is, moreover, commonly supplemented by 
arrangements which, in the ordinary circumstances of life, 
prevent other forces from stimulating the nerves connected 
with it, Not all natural forces have sense-organs with ref- 
erence to them developed in the Human Body; for exam- 
ple, we have no organ standing to electrical changes in the 
same relation that the eye does to light or the ear to 
sound. 

‘The Essential Structure of a Sense-Organ. In every 
sense-orgun the fundamental part is thus one or more end 
organs, which are highly irritable tissues (p. 31), 8 con- 
structed and so placed aa to be normally acted on by some 
one of the modes of motion met with in the external world. 
A sensory apparatus requires in addition at least a brain-cen- 
tre, and a sensory nerve-fibre connecting this with the ter- 
minal apparatus; but one commonly finds accessory parts 
added. In the eye, ¢.g., we have arrangements for bringing 
to a focus the light rays which are to act on the end 
organs of the nervo-fibres; and in the ear are found similar 
subsidiary parts, to conduct sonorous vibrations to the end 
apparatus of the auditory nerve. 

Secing and hearing are the two most specialized senses; 
the stimuli usually arousing them are peculiar and quite 
distinct from the gronp of general nerve stimuli (see p. 188), 
while those most frequently, or naturally, acting upon our 
other sense-organs are not so peculiar; they are forces which 
act as general nerve stimuli when directly applied to nerve- 
fibres, The end organs, however, as already pointed out 





408 THE HUMAN BODY, 


(p. 190), 90 increase the sensitiveness of the parts contain- 
ing them that degrees of change in the exciting forces, 
which would be totally unable to stimulate nerve-fibres 


themselves are appreciated. These terminal apparatuses 
are therefore as truly mechanisms enabling changes, which 
would not otherwise stimulate nerves, to excite them, as 
are the end organs in the eye or ear. 

‘The Causo of the Modality of our Sensations, Secing 
that the external forces usually exeiting our different sen- 
sations differ, and that the sensations do also, we might at 
first be inclined to believe that the latter difference de- 
pended on the former: that brightness differed from loud- 
ness because light was different from sound. In other 
words, we are apt to think that each sensation derives its 
specific character from some property of its external physi- 
cal antecedent, and that our eensations answer in some way 
to, and represent more or less accurately, properties of the 
form: of energy arousing them. It is, however, quite easy 

ve have no sufficient logical warrant for ench 

ht falling into the eye causes a sensation of 

feeling belonging to the visual group or 

since usually nothing else excites such 

entering the healthy eye always does, 

that the physical agent light is somo- 

ion of luminosity. But, as we have 

matter how we stimulate the optic 

; close the eyes and press 

a sensation of touch is 

e skin; but the pressure 

nd stimulates the optic nervo- 

luminous pateh seen 

osition as a bright body must 

that part of the expan- 

rn oma Br en, the same kind of 

, & visual rod fat the spi different 
paste an light, we 
f modality i ae r sen 





WHY OUR SENSATIONS DIFFER. 469 


giving rise to visual sensations. But then,since light and 

pressure, electricity and cutting, all cause visual sensations, 

we have no valid reason for supposing that light, more than 
either of the others, is really in any way like our sensation. 
of light: or that sight-feeling differs from sound-feeling 
because objectively light differs from sound. The eye is an 
organ specially set apart to be excited by light, and accord- 
ingly so fixed as to have its nerve-fibres far more often ex- 

cited by that form of force than by any other; but the fact 
that light sensations can be otherwise aroused shows plainly 

that their kind or character has nothing directly to do with 
any property of light. Just as by pinching or heating or 
galvanizing a motor nerve we can make the muscles attached 
to it contract, and the contraction has nothing in common 
with the excitant, 20 the visual sensation, as such, is inde- 
pendent of the stimulus arousing it and, of itself, tells 
us nothing concerning the kind of stimulus which has 
operated. 

Differences in kind between external forces being thus 
eliminated as possible causes of the modalities of our sen- 
sations, we next naturally fall back upon differences in the 
sense-organs themselves. They do undoubtedly differ both 
in gross and microscopic structure, and the fact that pres- 
sure on the closed eye arouses a touch-feeling where the 
skin is compressed, and a sight-feeling where the optic nerve 
is, might well be due to the fact that a peripheral touch- 
organ was different from a peripheral sight-organ, and the 
same force might therefore produce totally different effects 
on them and so cause different kinds of feelings. However, 
here also closer examination shows that we must seek far- 
ther. Sensation is not produced in a sense-organ, but far 
away from it in the brain; the organ is merely an apparatus 
for generating nervous impulses. If the optic nerves be 
divided, no matter how perfect the oyeballs, no amount of 
light will arouse visual sensations; if the spinal cord be cut 
in the middle of the back no pressure on the feet will cause 
a tactile or other feeling; though the skin, and its nerves 
and the lower half of the spinal cord be all intact. In all 
cases we find that if the nerve-paths between a sense-organ 





in sense-organs. 
might be that something in the sense-organ caused one sen- 
sation to differ from another. Each organ mightexcite the 
brain in » different way and lpia | 
so our sensations differ because our sense-organs did. Sucha 
view is, however, negatived by observations which show that 
perfectly characteristic sensations can be felt in the absence 
of the sense-organs through which they are normally ex- 
cited. Persons whose eyeballs have been removed by the 
surgeon, or completely destroyed by disease, have frequently 
afterwards definiteand unmistakable visual sensations, quite 
as characteristic as those which they had while still possess 
ing the visual end organs, The tactile sensations felt in 
amputated limbs, referred to above, afford another example 
of the sume fact. The persons still feel things touching their 
legs or lying between their long-lost toes; and the sen- 
sations are distinctly ¢actile and not in any way less different 
from visual or anditory sensations than are the 
ings following stimulation of those parts of the skin 
are still possessed. It is, then, clear that the modality — 
sensations is to be sought deeper than in properties of the 
end organs of the nerves of each sense. 
Properties of external forces and properties of me 
ral nerve-organs being excluded as causes of differences in 
kind of sensation, we come next to the sensory nerve-fibres 
themselves, Is it because optic nerye-fibres are different 
from auditory nerve-fibres that luminons sensations are 
different from sonorous? This question must be answered 
in the negative, for we have already (p. 193) seen reason to 
believe that all nerve-fibres are alike in essent 
and that their propertios are everywhere the same; that all 
they do is to transmit “nervous impulses” when excited, 
and that, no matter what the oxe’ itant, these impulses are 
molecular movements, always alike in kind, though they 
may differ in amount and in rate of succession. Since, 










WHY OUR SENSATIONS DIFFER. an 


then, all that the optic nerve does is to send nervous impulses 
to the brain, and all that the auditory and gustatory and 
touch and olfactory nerve-fibres do is the same, and these 
impulses are all alike in kind, we cannot explain the differ- 
ence in quality of visual and other sensations by any dif- 
ferences in property of the nerve-trunks concerned, any more 
than we could attempt to explain the facts that, in one case, 
an electric current sent through a thin platinum wire heats 
it, and, in another, sent through a solution of a salt decom- 
poses it, by assuming that the different results depend on 
differences in the conducting copper wires, which may be 
absolutely the same in the two cases, 

We are thus driven to conclude that our sensations 
primarily differ because different central nerve-organs in 
the brain are concerned in their production. That just as 
an efferent nerve-fibre will, when stimulated, cause a secre- 
tion if it go to a gland-cell, and a contraction of it to go 
to amusele-fibre, 80 an optic nerve-fibre, carrying impulses to 
one brain apparatus and exciting it, will cause a visual 
sensation, and a gustatory nerve-fibre, connected with 
another brain-centre, a taste sensation. In other words, 
our kinds of sensation depend fundamentally on the proper- 
ties of our own cerebral nervous system. For each special 
sense we have a neryous apparatus with its peripheral 
terminal organs, nerve-fibres, and brain-centres; and the 
excitement of this apparatus, no matter in what way, causes 
a sensation of a given modality, determined by the proper- 
ties of its central portion. Usually the apparatus is excited 
by one particular force acting first on its peripheral organs, 
but it may be aroused by stimulating its nerve-fibres 
directly or, as in certain diseased states (delirium), or under 
the action of certain drugs, by direct excitation of the centres, 
The sensations of dreams, frequently so vivid, and halluci- 
nations, are also probably in many cases due to direct 
excitation of the central organs of sensory apparatuses, 
though no doubt also often due to peripheral stimulation, 
But no matter how or where the apparatus is excited, pro- 
vided « sensation is produced it is always of the modality 
of that sense apparatus. 








gra] 
modality, {his character oan be AschTBad naly Er tea Sepa 
ties (so that we may bore ee 
of whose optic nerve was in 
the outer end of his anditory, and the inner end Bini 
anditory with the outer end of his optic, might hear a pic- 
ture and see a symphony), yet, perhaps, differences in the 
rhythm or intensity of afferent nervous impulses may cause 
differences in modality in less differentiated senses, Thus 
contact with a cold soft object may be felt as heat, 
thought to be due to the approach of a warm body; and 
from such cases we must perhaps conclude that touch and 
temperature depend on excitations in different ways of one 
and the same brain-centre; impulses of a certain rhythm 
producing a sensation of heat, and those of another (deter 
mined by the different heat and touch end organs) causing 
a tactile sensation, If this be so, however, heat and touch 
would be but extreme varieties of one kind of sensation, 
and comparable to yellow and blue. Again, a heavy pres 
sure, gradually increased, arouses sensations which pass im- 
perceptibly from touch to pain, and the result may be due 
to the fact that regular and orderly afferent im 
determined through tactile rerve-endings, excite the centre 
in one way; while irregular, disorderly, and violent, excited 
when the nerve-trunks beneath the skin are directly stimn- 
lated, may cause a different sensation; much as the same 
musical notes combined in one order cause pleasure but in 
another are disagreeable, causing a sort of pain, although 
the same brain-centres are stimulated in the two eases. 
The pain from a heavy weight may, however, be merely dno 
to the fact that it excites the nerves very powerfally and 
gives rise to impulses which radiate farther in the brain than 
those causing touch senzations, and so excite new centres, 
the modality of which is a pain sensation. 

However differences in nervous rhythm may account for 
minor differences in sensation, it remains clear that the 
characters of our sensations are creations of our own organ- 


= 


FECHNER'S LAW. 


ism; they depend on properties of our Bodies and not on 
properties of external things, except in so fur as these may 
or may not be adapted to arouse our different sensory 
apparatuses to activity. From the kind of the sensation we 
cannot, therefore, argue as to the nature of the excitant: we 
have no more warrant for supposing that light is like our 
sensation of light than that the knife that cuts ua is like 
our sensation of pain. All that we know with certainty is 
states of our own consciousness, and although from these we 
form working hypotheses as to an external universe, yet, 
granting it, we have no means of acquiring any real knowl- 
edge as to the properties of things about us. What we 
want to know, however, for the practical purposes of life 
is, not what things are, but how to use them for our advan- 
tage, or to prevent them from acting to our disadvantage; 
and our senses enable us to do this sufficiently well. 

The Psycho-Physical Law. Although our sensations are, 
in modality or kind, independent of the force exciting them, 
they are not so in degree or intensity, at least within cer- 
tain limits. Wecannot measure the amount of a sensation 
and express it in foot-pounds or calories, but we can get a 
sort of unit by determining how small a difference in sen- 

oncan be perceived. Supposing thissmallest perceptible 

ice to be constant within the range of the same sense, 

(which is not proved,) it is found that it is produced by dif- 
ferent amounts of stimuli, measured objectively as forces; 
and that there exists in some cases a relation between the two 
which can be expressed in numbers. ihe increase of stim- 
ulus necessary to produce the smallest perceptible change in 
a sensation is proportional to the strength of the stimulus 
already acting; for example, the heavier a pressure already 
‘on the skin the more must it be increased ordimin- 

order that the increase or diminution may be felt. 
Expressed in another way the facts may be put thus: sup- 
pose threo degrees of stimulation to bear to one another ob- 
jectively the ratios 10, 100, 1000, then their subjective ef- 
fects, or the amounts of sensation aroused by them, will be 
respectively as 1, 2, 3; in other words, the sensation in- 





an THE HUMAN BODY. 


ereases proportionately to the if 

stimulus. Examples of this, which is known as “ 

or “Fechner’s psychophysical law” will be hereafter 
pointed ont, and are readily observable in daily life; we 
have, for example, « luminous sensation of certain intensity 
when a lighted candle is brought intoa darkroom; this sen- 
sation is not doubled when a second candle is brought in; 
and is hardly affected at all by a third. The law is only 
true, however (and then but approximately), for sensations 
of medium intensity; it is applicable, for example, to light 
sensutions of all degrees between those aroused by the light 
of a candle and ordinary clear daylight: but it is not trie 
for luminosities so feeble as only to be seen at all with diffi- 
culty, or 8o bright as to be dazzling. 

Besides their variations in intensity, dependent on yaria- 
tions in the strength of the stimulus, our sensations also 
vary with the irritability of the sensory apparatus itself; 
which is not constant from time to time or from person to 
person. In the above statements the condition of the sense- 
orgun and its nervous connections is presumed to remain 
the came throughout. 

Perceptions. In every sensation we have to carefully 
distinguish between the pure sensation and certain rer 

nded upon it; we have to distinguish between whut 
al and what we think we feel; and very often 
ieve we do feel when we do not. 


leads us to ascribe certain sensations, those aroused 
organs of special sense, to extornal objects—that outer 
¢ pares which leads us to form ideas 


stimulation and ba et 
1 representation 
quite certain that we ean feel 





PERCEPTIONS. 4u5 


nothing but states of ourselves, but, as already pointed 
out, we have no hesitation in saying we feel a hard ora 
cold, a rough or smooth body. When we look at a distant 
object we usually make no demur to saying that we perceive 
it, What we really feel is, however, the change produced by 
it in our eyes. There are no partsof our Bodies reaching 
to a tree or a housea mile off—and yet we seem to feel all 
the while that we are looking at the tree or the house and 
fecling them, and not merely experiencing modifications of 
our own eyes or brains. When reading we feel that what 
we really sce is the book; and yet the existence of the book 
isa judgment founded on a state of our Body, which alone 
is what we truly feel. 

We have the same experience in other cases, for example 
with regard to touch. 

Hairs are quite insensible, but are imbedded in the sen- 
sitive skin, which is excited when they are moved. But if 
the tip of a hair be touched by some external object we be- 
lieve we feel the contact at its insensible end, and not in 
the sensitive skin at its root. So, the hard purts of tho 
teeth are insensible; yet when we rub them together we refer 
the seat of the sensation aroused to the points where they 
touch dne another, and not to the sensitive parts around 
the sockets where the sensory nerve impulse is really started. 

Still more, we may refer tactile sensations, not merely to 
the distal ends of insensible bodies implanted in the skin, 
but to the far ends of things which are not parts of our 
Bodies at all; for instance, the distant end of a rod held 
between the finger and a table. We then believe we feel 
touch or pressure in two places; one where the rod touches 
our finger, and the other where it comes in contact with 
the table. We have, simultaneously, sensations at two 
places separated by the length of the rod. If we hold the rod 
immovably on the table we feel only its end next the fin- 
ger. If we conld fix it immovably on the finger while the 
other end was movable on the table, we would lose the sen- 
sation at the finger and only believe we felt the pressure 
where the rod touched the table. When a tooth is touched 
with a rod we only feel the contact at its end, unless it ix 





476 THE HUMAN BODY, 


loose in its socket; and then we get two sensations on 
touching its free end with a foreign body. 

This irresistible mental tendency to refer certain of our 
states of feeling to causes outside of our Bodies, and either 
in contact with them or separated from them by a certain 
space, is known as the phenomenon of the extrinsic refer- 
ence of owr sensations. 

‘The discussion of its origin belongs properly to Psychol- 
ogy, and it will suffice here to point out that it seems largely 
to depend on the fact that the sensations extrinsically referred 
can be modified by movements of our Bodies. Hunger, 
thirst, and toothache all remain the same whether we turn 
to the right or left, or move away from the place we are 
standing in. But a sound is altered. We find that in a 
certain position of the head it is heard more by the right 
ear than the left; but on turning round the reverse is the 
case; and half way round the loudness in each ear is the 
same. Hence we are led, by mental laws outside of the 
physiological domain, to suspect that its cause is not in our 
Body, but outside of it; and depends not on a condition of 
the Body but on something else. And this is confirmed 
when going in one direction we find the sound increased, 
and in the other that it is diminished. ‘This implies that 
we have a knowledge of our movements, and this we gain 
through the muscular sense. Tt constitutes the reactive side 
of our sensory life, associated with the changes we produce 
in external things; and is correlated and contrasted with 
the passive side, in which other things produce sensations 
by acting upon us. 

As regards our common sensations we find something of 
the same kind. ‘The more readily they can be modified by 
movement the more definitely do we localize them in space, 
though in this case within the Body instead of ontside it. 
Hunger and nausea can be altered by pressure on the pit 
of the stomach; thirst by moistening the throat with water; 
the desire for oxygen (respiration-hunger) by movements of 
the chest; and so we more or less definitely ascribe these 
sensations to conditions of those parts of the Body, Other 
meral sensations, as depression, anxiety, and 60 on, are not 


_ 












SENSORY ILLUSIONS, 


modifiable by any particular movement, and 0 appear to 
us rather head states, pure and simple, than bodily 
sensations. 

Sensory Tlusions. ‘I must believe my own eyes” and 
‘we can’t always believe our senses” are two 
sions frequently heard, and.cach expressing a truth. No 
doubt a sensation in itself is an absolute incontrovertible 
fact: if I feel redness or hotness I do feel it and that is an 
end of the matter: but if I go beyond the fact of my having 
a certain sensation and conclude from it as to properties 
of something else—if I forma judgment from my sensation 
—I may be totally wrong; and in s0 far be unable to 
believe my eyes or skin, Such judgments are almost 
inextricably woven up with many of our sensations, and so 
closely that we cannot readily separate the two; not even 
when we know that the judgnient is erroneous. 

For example, the moon when rising or setting, appears 
bigger than when high in the heayens—we seem to feel 
directly that it arouses more sensation, and yet we know 
certainly that itdoes not. With a body of a given brightness 
the amount of change produced in the end organs of the 
eye will depend on the size of the image formed in the 
eye, proyided the same part of its sensory surface is acted: 

Now the size of this image depends on the distance 
of the object; it is smaller the farther off it is and bigger 
the nearer, and measurements show that the area of the 
sensitive surface affected by the image of the rising moon 
is no bigger than that affected by it when overhead. Why 
then do we, even after we know this, see it bigger? ‘The 
reason is that when the moon is near the horizon we imagine, 
unconsciously and irresistibly, that it is farther off; even 
astronomers who know perfectly that it is not, cannot help 
forming this unconscious and erroneous judgment—and to 

the moon appears in consequence larger when near the 
horizon, just as it does to loss well-informed mortals. Tn fact 
we have a conception of the sky over which the moon tray- 
els, not as a half sphere but as somewhat flattened, and 
hence when the moon is at the horizon we unconsciously 
judge that it is farther off than when overhead. But any 








478 THe HUMAN BODY. 


body which excites the same extent of the 

of the eye at a great distance that another does at xt 
be larger than the latter; and so we conclude that the moon 
gt the horizon is larger than the moon in the zenith, and 
are ready to declare that we see it so, 

So, again, a small bit of light gray paper on a white sheet 
looks gray: but placed on a large bright green surface it 
looks purple; and on a bright red surface looks blue-green. 
As the same bit of gray paper is shifted from one to the 
other we see it change its color: it arouses in us different 
feelings, or feelings which we interpret differently, although 
objectively the light reflected from it remains the game. 
Similarly a medium-sized man alongside of a very tall one 
appears short, but when walking with a very short one, tall. 

Such erroneous perceptions as these are known as sensory 
Meet and we ought to be constantly on guard against 
them. 





CHAPTER XXXI. 
THE EYE AS AN OPTICAL INSTRUMENT. 


The Essential Structure of an Eye. Every visual organ 
consists primarily of a nervous expansion, provided with 
end organs by means of which light is enabled to excite 
nervous impulses, and exposed to the access of objective 
light; such an expansion is called a retina. By itself, 
however, 4 retina would give no visual sensations referable 
to distinctly limited external objects; it would enable its 
possessor to tell light from darkness, more light from less 
light, and (at Jeast in its highly developed forms) light of 
one color from light of another color; but that would be all, 
Were our eyes merely retinus we could only tell a printed 
page froma blank one by tho fact that, being partly covered 
with black letters, (which reflect leas light,) it would excite 
our visual organ less powerfully than the spotless white 
page would. In order that distinet objects and not merely 
degrees of luminosity may be seen, some arrangement is 
needed which shall bring all light entering the eye from 
one point of a luminous surface to n focus again on one 
point of the sensitive surface. If A and # (Fig, 121) be 
two red spots on a black surface, X, and rr be a retina, 
then rays of light diverging from A would fall equally on 
all parts of the retina and excite it all a little; so with rays 
starting from B. The sensation aroused, supposing the 
retina in connection with the rest of the nervous visual 
apparatus, would be one of a certain amount of red light 
reaching the eye: the red spots, as definite objects, would 
be indistinguishuble. If, however, a convex glass lens 
L (Fig. 122) be put in front of the retina, it will cause to 
converge again to a single point all the rays from A falling 








THE BYEBLIDS 481 


‘apparatuses, as, for example, some controlling the light- 
converging power of the modia, and others regulating the 
size of the aperture (pupil) by which light enters, Out- 
side the ball lie muscles which bring about its movements, 
and other purts serving to protect it. 

Each orbit is a pyramidal cavity occupied by connective 
tissue, muscles, blood-yessels and nerves, and in great part by 
fat, which forms a soft cushion on which the back of the 
eyeball lies and rolls during its movements, The contents 
of the orbit being for the most part incompressible, the eye 
cannot be drawn into its socket. It simply rotates there, 
as the head of the femur does in the acetabulam. When 
the blood-vessels are gorged, however, the eyeballs may be 
cansed to protrude (as in strangulation), and when the ves- 
sels empty it recedes somewhat, as is commonly seen after 
death, The front of the eye is exposed for the purpose of 
allowing light to reach it, bat can be covered up by the 
eyelids, which are folds of integument, movable by muscles 
and strengthened by plates of fibro-cartilage. At the edge 
of each eyelid the skin which covers its outside is turned 
in, and becomes continuous with a mucous membrane, the 
conjunctiva, which lines the inside of each lid, and also 
covers all the front of the eyeball as a closely adherent 
layer. 

‘The upper eyelid is larger and more mobile than the 
lower, and when the eye is closed covers all its transparent 
part. It has a special muscle to raise it, the levator palpe- 
bra superioris. "The eyes are closed by a flat circular mus- 
cle, the orbiewlaris palpebrarum, which, lying on and around 
the lids, immediately beneath the skin, surrounds the aper- 
ture between them. At their outer and inner anglos (ean- 
thi) the eyelids are united, and the apparent size of the eye 
depends upon the interval between the canthi, the eyeball 
itself being nearly of the same size in all persons, Near 
the inner canthus the line of the edge of each eyelid 
changes its direction and beeomes more horizontal. At 
this point is fonnd asmull eminence, the lachrymal papilla, 
on cach lid. For most of their extert the inner surfaces 
of the eyelids are in contact with the outside of the eye- 





. 
THE HUMAN BODY. 


ball but, near their inner ends, a red vertical fold of c 
junctiva, the semilunar fold ( plica semilunaris) int 
This is remnant of the third eyelid, or 
membrane, found largely developed in many animals, as 
birds, in which it can be drawn all over the exposed part 
of the eyeball, Quite in the inner corner is a reddish ele- 
vation, the caruncula lackrymalis, caused by a collection of 
sebaceous glands imbedded in the sermilunar fold, it 
along the edge of cach eyelid are from twenty to thirty 
minute compound sebaceous glands, called the Meibomian 
follicles. Their secretion is sometimes abnormally abun- 
dant, and then appears as a yellowish matter along the 
edges of the eyelids, which often dries in the night and 
causes the lids to be glued together in the morning, The 
eyelashes are short curved haira, arranged in one or two 
rows along each lid where the skin joins the conjunctiva. 

The Lachrymal Apparatus consists of the tear-gland in 
each orbit, the ducts which carry its sceretion to the upper 
eyelid, and the canals by which this, unless when excessive, 
is carried off from the front of the eye without running 
down over the face. The /achrymal or tear gland, about 
the size of an almond, lies in the upper and outer part of 
the orbit, near the front end. It is a compound racemore 
gland, from which twelve or fourteen ducts run and 
in a row at the outer corner of the upper eyelid. The se- 
cretion th /polired out is spread evenly over the 

the movements of winking, and keeps it 
si it is drained off by two lachrymal canals, one 

of which opens by a smal! 





MUSOIES OF THE EYEBALI. . 483 


such quantity as to be drained off into the nose, from 
which they flow into the pharynx and are swallowed, 
When the lachrymal ducts are stopped up, however, their 
continual presence makes itsclf unpleasantly felt, and may 
need the aid of a surgeon to clear the passage. In weeping 
the secretion is increased, and then not only more of it en- 
tors the nose, but some flows down the cheeks, The fre- 
quent swallowing movements of a erying child, sometimes 
spoken of as ‘‘gulping down his passion,” are due to the 
need of swallowing the extra tears which reach the pharynx. 








Fro. ish—The ereballs and thelr muscles ea seen when the root of the orbit 
has been removed and the fat in the eavity hax been partly cleared away, On 
{he right side the superior rectus muscle has been eut away. a, external Teo: 


The Muscles of the Eye (Fig. 123). The eyeball is 
spheroidal in form and attached behind to the optic nerve, n, 
somewhatas a cherry might be toa thick stalk. On its outside 
are inserted the tendons of six muscles, four s¢raight and two 
oblique. The straight muscles lie, one (superior rectus), 5, 
above, one (inferior rectus) below, one (external reciws), a, 
outside, and one (inéernal rectus), #, inside the eyeball. Each 
arises behind from the bony margin of the foramen through 
which the optic nerve enters the orbit. In the figure, 


= 


THE HUMAN 


which represents the orbits opened 

rectus of the right side has been ret 

oblique or pulley (trochlear) muscle, t, arises. b 

the straight muscles and forms 

4, Which passes through a fibro-cartilaginons 

pulley, placed at the notch in the frontal hone, 

bounds superiorly the front end of the orbit. ‘The tendon 
then turns back and is inserted ints Ce aaebeliaeeeae 
the upper and outer recti muscles. The i 

muscle does not arise, like the rest, at the backof the 

but near its front at the inner side, close to the ean 
sac. It passes thence outwards and backwards beneath the 
eyeball to be inserted into its outer and posterior part. 

‘The inner, upper, and lower straight muscles, the inferior 
oblique, and the elevator of the upper lid are supplied by 
branches of the third cranial nerve (see p. 168). ‘The sixth 
cranial nerve gocs to the outer rectus; and the fourth to 
the superior oblique. 

‘The eye may be moved from side to side; up or down; 
obliquely, that is neither truly vertically nor horizontally, 
but partly both; or, finally, it may be rotated on its antero- 
posterior axis, The oblique movements are always accom- 

light amount of rotation, When the glance is 
the loft external rectus and the right in- 

wice versa; when up, both superior recti; 

he inferior. The superior oblique muscle 

e front of the eye downwards and 

n amount of rotation; the inferior 

Tn oblique movements two of 

an upper or lower with an inner 

ie one of the oblique algo always 

rotation rarely, if ever, occur 


ts of the eyes by which 

ly towards the same point 
ment of all its nervo-muson- 
rdination is deficient the 
eternal squind would be 
tus of that eye, for then, 





ANATOMY OF BYEBALL. 


when the eyeball had been turned ont by the external rec- 
tus, it would not be brought back again to its median 
position. A left infernal squint would be caused, similarly, 
by paralysis of the left external rectue; and probably by 
disease of the sixth cranial nerve or its brain-centres. 
Dropping of the upper eyelid (ptosis) indicates paralysis of 


Tro, 1— The. ards a eae fs hortzomtal section froma beferebest. 2, sulerotia 


8; Jumetion of c Reni gene é posterior 


its elevator muscle (p. £81), and is often a serious eymptom, 
as pointing to disease of the brain-parts from which it is 
innervated. 

The Globo of the Eye is on the whole spheroidal, but 
consists of segments of two spheres (see Fig. 124), a portion 
of asphere of smaller radius forming its anterior transpareut 
part and being set on to the front of its posterior segment, 
which is part of a larger sphere. From before back it 





486 THE HUMAN BODY. 


measures about 22.5 millimeters (,% inch), and from side 
to side about 26 millimeters (linch). Except when looking 
at near objects, the antero-posterior axes of the eyeballs are 
nearly parallel, but the optic nerves diverge considerably 
(Fig. 123); each joins itseyeball, not at idiseentie bat about 
2.6 mm. (ys inch) on the nasal side of the posterior end of 
its antero-posterior axis. In general terms the eyeball may 
be described as consisting of three coats and three refract- 
ing media. 

The outer coat, 1 and 3, Pig. 124, consista of the sclerotic 
and the cornea, the latter being transparent and situated in 
front; the former is opaque and white and covers the back 
and sides of the globe and part of the front, where itis seen 
between the eyelids as the whife of the eye. Both are 
tough and strong, being composed of dense aonnective tis- 
sue, The white of the eye and the cornea are also covered 
over by a thin layer of the conjunctiva, 4and 5. Behind 
the proper connective-tissne layer, 3, of the cornea is a thin 
structureless membrane, 6, lined inside by a single layer of 
epithelial cells; it is called the membrane of Descemet, or 
posterior elastic layer. 

‘The second coat consists of the choroid, 9, 10, the ciliary 
processes, 11, 13, and the fris, 14, The choroid consists 

sels supported by loose connective tisene 
us corpuscles, Which in its inner layers are 
n or black pigment granules, 

eyeball, where it begins to dimin- 
oroid is thrown into plaits, the ciliary 
yond these it continues as the ris, 

d part of the eye which is seen 

r he centre of it this a circular 

md coat does not, like the 

the ball. In the iris are 

bres; a circular around the 

it when they contract; 

"to the outer margin of 

e the pupil. The 

r of lighter or darker 

eye, and more or less 





HISTOLOGY OF RETINA. 487 


abundant according as the eye is black, brown, or gray. In 
blue eyes the pigment is confined to the deeper layers and 
modified in tint by light absorption in the anterior color- 
less strata through which the light passes. 

‘The third coat of the eye, the retina, 15, is its essential 
portion, being the part in which the light produces those 
changes that give rise to impulses in the optic nerve, It 
is a still less complete enyelope than the second tunic, ex- 
tending forwards only as far as the commencement of the 
ciliary processes, at least in its typicalform. It is extremely 
soft and delicate and, when fresh, transparent. Usually 
when an eye is opened it looks colorless; but by taking 
proper precautions the natural purple color of some of its 
outer layers can be seen. Its most external layer, more- 
over, is composed of black pigment cells. On its inner 
surface two parts, different from the rest, can be seen in a 
fresh eye. One is the point of entry of the optic nerve, 
16, the fibres of which, penetrating the sclerotic and 
choroid, spread ont in the retina. At this place the retina 
is whiter than elsewhere and presents an elevation, the 
optic mound. The other peculiar region is the yellow spot 
(macula Iutea), 18, which lies nearly at the posterior end of 
the axis of the eyeball and therefore ontside the optic mound; 
im its centre the retina is thinner than elsewhere and so a 
pit( fovea contralis), 18,18 formed. This appears black, the 
thinned retina there allowing the choroid to be seen through 
it more clearly than elsewhere. In Fig. 125 is represented 
the left retina as seen from the front, the elliptical darker 
patch abont the centre being the yellow spot, and the 
white cirele on one side, the optic monnd. The vossels of 
the retina arise from an artery (17, Fig. 124) which runs 
in with the optic nerve and from which branches diverge 
as shown in Fig. 125, 

The Microscopic Structure of the Retina. A simplified 
stratum, continuous with the proper retina, wnd formed of 
a layer of nucleated columnar cells is continued over the 
ciliary processes; elsewhere the membrane has a very com. 
plex structure and a section taken, except at the yellow 
spot or the optic mound, shows ten layers, partly sensory 





a cexinning (Fig 126) on the inner side we find, first, the 
internal limiting membrane, 1, a thin structureless layer, 


Next comes the nerve-fibre layer, 2, formed by radiating 
fibres of the optic nerve; third, the nerve-cell layer, 3; 


rotina as it would be seen If the front part of the eyeball 
inreous humor were removed. 


ppp 


process running to the inner 
ter running to, 6, the outer 


Stbre layer, %, or outer 
‘and thin fibres on each 
with a nucleolus. Next 
brane, 8, perforated by 
nd cones, 9, of the ninth 
Ontside of all, ext 

In addition, cer- 





HISTOLOGY OF RETINA. 489 


tain fibres run vertically through the retina from the inner 
to the outer limiting membrane; they are known as the 
radial fibres of Miller aud give off lateral branches, which 
are especially numerous in the molecular layers. 


~ a 
Fro. 12%.— A section through the retina from {ts anterlor or inner 


ion surface, 
ith the id memly ano, lo it outer. tact with the 
ternal ll 


‘granular iat wolewular 
iting metnbrane; 9, rod and cane 

On account of the way in which the supporting and essen- 
tial parts are interwoven in the retina it is not easy to track 





the latter through it. We shall find, however 
XXXI1.). that light first acts upon the rod and cone 
traversing all the thickness of inner strata of the retina to 
reach this, before it can start those changes which result in 
visual sensations; and it is theretore probable that the rods 
and cones arc in direct continuity with the optic nerve- 
fibres, The limiting membranes, with the fibres of Miller 
and their branches, are undoubtedly accessory. 

Each rod and cone consists of an ower and an fnner 
segment, The outer segments of both tend to split up trans-_ 
versely into disks and are very similar, except that those of 
the rods are longer than those of the cones and do nottaper 
as the latter do. The inner segments of the cones aro 
swollen, while those of the rods are narrow and nearly ey- 
lindrical. Over most of the retina the rods are longer and 
much more numerous than the cones, but near the ciliary 
processes they cease before the cones do, and in the yellow 
spot elongated cones alone are found. Tu this region the 
whole retina is niuch modified; at its margin all the layers 
are thickened but especially the nerve-cell layer, which is 

i en thick, while elsewhere the cells are found 
in but one or two strata. All the fibres also are oblique, 
reaching in to become continuous with the cones of the 


0 the depression is produced. ‘Lhe fovea is 
nost acute vision; whon we look at an object 
urn our eyes 60 that the light proceeding from 





THE REFRACTING MEDIA OF THE EYE. 491 


30, and a posterior, 31 (Fig. 124). Chemically, the aque- 
ous humor consists of water holding im solution 4 small 
amount of solid matters, mainly common salt. 

The crystalline lens (28, 26, 27) is colorless, transparent, 
and biconvex, with its anterior surface less curved than 
the posterior. It is surrounded bya capsule, and the inner 
edge of the iris lies incontact with it in front. In consist- 
ence it is soft, but its central layers are rather more dense 
thun the outer, 

‘The vitreons humor is a soft jelly, enveloped in a thin 
capsule, the Ayaloid membrane. In front, this membrane 
splits into two layers, one of which, 22, passes on to be 
fixed to the lens n little in front of its edge. This layer is 
known as the suspensory ligament of the lens; its line of at- 
tachment around that organ is not straight but sinuous 
as represented by the curved line between 28 and 26 in Fig. 
124. The space between the two layers into which the 
hyaloid splits is the canal of Petit. The vitreous humor 
consists mainly of water and contains some salts, a little 
albumin, and some mucin. It is divided up, by delicate 
membranes, into compartments in which its more liquid 
portions are imprisoned. 

The Ciliary Muscle. Ruuning around the eyeball 
where the cornea joins the sclerotic is a little vein called 
the canal of Schklemm; it is seen in section at 8 in Fig. 124, 
Lying on the inner side of this canal, just where the iris 
and the ciliary processes meet, there is some plain muscular 
tissue, imbedded mainly in the middle coat of the eyeball 
and forming the ciliary muscle, which consists of a radial 
and a circular portion. ‘The radial part is much the larger, 
and arises in front from the inner surface of the sclerotic; the 
fibres pass back, spreading ont as they go, and are inserted 
into the front of the choroid opposite the ciliary processes. 
‘The circular part of the muscle lies around the outer rim of 
the iris. The contraction of the ciliary muscle tends to pull 
forward (radial fibres) and press inward (circular fibres) the 
front part of the choroid, to which the back part of the sus- 
pensory ligament of the lens isclosely attached. In this way 
the tension exerted on the lens by its ligament is diminished, 





= _ 
THE HUMAN BODY, 


Tho Properties of Light. Before proceeding to the 
study of the eye as an optical instrument, it is necessary to 
recall briefly certain properties of light. 

Light is considered as a form of movement of the 
of an hypothetical medium, orether, the vibrations in 
plies at right angles to the line of propagation of the 
light. When a stone is thrown into a pond a series of 
circular waves travel from that point in a horizontal direc- 
tion over the water, while the particles of water themselves 
move up and down, and cause the surface inequalities 
which we see a3 the waves. Somewhat similarly, a 
spread out from a luminous point, but in the same medinm 
travel equally in all directions so that the point is surrounded 
by shells of spherical waves, instead of rings of cireular 
waves traveling in one plane only, as those on the surface 
of the water. Starting from a Inminous point 
would travel in all directions along the radii of a sphere of 
which the point is the centre; the light propagated along 
one such radius is called a ray, and in each ray the ethereal 
particles swing from side to side in @ plano perpendiewlar 
to the direction of the ray. Taking a particle on any 
it would swing aside a certain distance from it, then back 
to it aguin, and across for a certain distance on the other 
ide; and then back to its original position on the line of 
the ray. Such a movement is an oscillation, and takes a 

i n lights of certain kinds tho periods of oxcilla- 


s 5 owing in the same time no matter 
at or small. Light composed of 

of oscillation are all equal ix 

ple light, while light made of a 


eadily emitted from a point, 

+ along a ray, we come to particles 
say at their greatest dis- 

rest; just as in'the concentrio 
rowing in a stone we would 





PROPERTIES OF LIGHT: 493 


along any radius meet, at intervals, with water raised most 
above its horizontal plane as the crest of a wave, or depressed 
most below it as the hollow of a wave. The distance along 
the ray from crest to crest is called a wave-length and is 
always the same in any given simple light; but differs in 
different-colored lights; the briefer the time of an oscillation 
the less the wave-length. 

When light falls on « polished surface separating two 
transparent media, as air and glass, part of it is reflected 
or turned back into the first medium; part goes on into 
the second medium, and is commonly deviated from its 
original course or refracted. ‘The original ray falling in the 
surface is the incident ray. 

Let A B (Fig. 127) be the 
surface of separation; ax the 
incident ray; and CD the 
perpendicular or normal to 
the surface at the point of 
incidence: az 0 will then be 
the angle of incidence. Then 
the reflected ray makes an 
angle of refléction with the 
normal which is equal to 
the angle of incidence; and 
the reflected ray lies in ito baeeran! ae Sree 
the same plane a3 the inci- surfscs At the polmt of incidence. i 
dent ray and the normal to fret wie flagrant | 
the surface ut 2 The re- 
fracted ray lies also in the a Oa 
same plane as the normal and ©* “tt He angle a= 0. 
the incident ray, but does not continue in its original direc- 
tion, #/; if the mediam below 4 # be denser than that 
above it, the refracted ray is bent in the direction zd 
nearer the normal, and making with it an angle of refrac- 
tion, Dxd, smaller than the angle of incidence, ax @. If, 
on the contrary, the second medinm be less dense than the 
first, the refracted ray eg is bont away from the normal, 
and makes an angle of refraction, Dxg, greater than the 
angle of incidence, he ratio of the sine of the angle of 





494 THE HUMAN BODY. 


incidence to that of the angle of refraction is always the 
same for the same two media with light of the same wave- 
length. When the first medium is air the ratio of the sine 
of the angle of refraction to that of the angle of incidence 
is called the refractive index of the second medium. The 
greater this refractive index the more is the refracted ray 
deviated from its original course. Rays which fall perpen- 
dicularly on the surface of separation of two media pass on 
without refraction. 

‘The shorter the oscillation periods of light-rays the more 
they are deviated by refraction. Hence mixed light when 


Fro. 128.—Diagram illustrating the dispersion of mbved tight by a prem. 


sent through a prism is spread out, and decomposed into 
its simple constituents. For let a # (Fig. 128) be a may of 
H composed of a set of short and a set of long 
When it falls on the surface A B of 

n which enters will be refracted 

but the short waves more than the 

rmer will take the direction x y, and 

On emerging from the prism 

od, but now from the nor- 


e ray zy, made up of shorter 
eviated, as in the direction yr, and 





REFRACTION BY LENSES. 495 


the long waves leas, in the directions r. If a screen were 
put at SS, we would receive on it at separate points, v and 
r, the two simple lights which were mixed together in the 
compound incident raya. Such a separation of light-rays 
is called dispersion. 

Ordinary white light, such as that of the sun, is com- 
posed of ethereal vibrations of all possible lengths. Henee 
when such light is sent through a prism it gives a contin- 
uous band of light-rays, known as the solar spectrum, 
reaching from the least refracted to the most refracted and 
shortest. The exceptions to this statement due to Frauen- 
hofer’s lines (see Physics) are uneszential for our present 
purpose. All of the simple lights into which the compound 
solar light is thus separated do not, however, excite in us 
visual sensations when they fall into the eye, but only cer- 
tain middle ones. If solar light were used with the prism, 
Fig. 125, certain least refracted rays between r and S would 
not be seen, nor the most refracted between v and S; while 
between » and ¢ would stretch a luminons band exciting in 
us the series of colors red (due to the least refracted visible 
rays), snecessively throngh orange, yellow, green, bright 
blue, and indigo, to violet, which latter is the sensation 
aroused by the most refrangible visible rays. The still 
shorter waves beyond the violet, are known mainly by their 
chemical effects and make up whut are called the actinic 
rays; the longer invisible waves, beyond the red, exert a 
powerful heating influence and compose the fiermal or dark 
heat rays, The eye, as an organ for making known to us 
the existence of ethereal vibrations, has, therefore, only a 
limited range. 

Refraction of Light by Lenses. In the eye the refract- 
ing media have the form of lenses thicker in the centre 
than towards the periphery; and we may here confine our- 
selves therefore to such converging lenses. Lf simple light 
from # point A, Fig. 122, fall on such a lens its rays, 
emerging on the other side, will take new directions after 
refraction and meet anew ata point, a, after which they again 
diverge. If a screen, rr, be held at a it will therefore 
receive an image of the luminous point 4. For every con- 





THE HUMAN BODY. 


verging lens there is such a point behind it at which the 

rays from a given point in front of it meet: the point of 

ing is called the conjugate focus of the point from 

which the rays start. If instead of a Inminous point a 

luminous object be placed in front of the lens an image of 

the object will be formed at a certain distance behind it, for 

all rays proceeding from one point of the object will meet 

in the conjugate focus of that point behind. The image 
1s inverted, as can be readily seen from Fig. 129. All rays 

from the point A of the object 

meet at the point @ of the 

image; those from B at }, and 

those from intermediate points 

at intermediate positions. If 

the single lens were replaced 

ry ste Forman oa mr ege s by several combined so as to 

form an optical system the 

general result would be the same, provided the system 

were thicker in the centre than at its periphery, 

‘The Camora Obscura, as used by photographers, is an 

instrament which seryes to illustrate the formation of 

aang by converging systems of lenses. It consists of a 


round re those images are only well 
, which are at such a distance in 


he glass behind the lens: objects 
nfused and indistinet images; 

) between the lenses and the 
‘focusing the instra- 

For near objects the 

the surface on which the 

for distant nearer. The 

en from Fig. 130. If the 

lel rays ac and } d, pro- 

t object, to a foons at z, 





REFRACTION IN THE EYE, 497 


then the diverging rays fc and fd, proceeding from a nearer 
point, will be harder to bend round, 90 to speak, and will 
not meet until a point y, farther behind the system than 
zis, The more divergent the rays, or what amounts to the 
same thing, the nearer the points they proceed from, the 
farther behind the refracting system will y be. 


Fr. 192.—Dingram fflustrating the need of “focusing” in an optical instru 


The eye is such a system, made up of the four refracting 
media, cornea, aqueous humor, lens, and vitreous humor. 
‘These four media are, however, reduced to three prac- 
tically, by the fact that the indices of ‘refraction of the 
cornea and aqueous humor are the same, so that they act 
together as one converging lens. The surfaces at which 
refraction ocours are—(1) that between the air and ihe 
cornea, (2) that between the aqueous homor and the front 
of the lens, (3) that between the vitreous humor and the 
back of thelens, The refractive indices of thove media are 
—the air, 1; the aqueous humor, 1.3379; the lens (average), 
1.4545; the vitreous humor, 1.3379. From the laws of the 
refraction of light it therefore follows that (Fig. 131) the 
rays cd will at the corneal surface be refracted towards the 
normals WV, V,and take the coursede. At the front of 
Jenses they will again be refracted towards the normals to 
that surface and take the course ¢ f; at the buck of the lens, 
passing from a more refracting to a less refracting medium, 
they will be bent from the normals .V’’ and take the course 
fg. Wf the retina be there, these parallel rays will therefore 
be brought to a focus on it. In the resting condition of 
the natural eye that is what happens to parallel rays entering 
it: and, since distant objects send into the eye rays which 
are practically parallel, such objects are seen distinctly 





498 THE HUMAN BODY. 


without any effort; all rays emanating from a point of the 
object meet again in one point on the retina, 
Accommodation, Points on near objectssend into the eye 
diverging rays: these therefore would not come toa focus on 
the retina but behind it, and would not be sen distinctly, 
did not some change occur in the eye; sinee we can see them 
«quite plainly if we choose (unless they be very near indeed), 
there must exist some means by which the eye is adapted 
or accommodated for looking at objects at different distances. 
That some change does occur one can, also, readily prove 


Fro, 181. —Diagram illustrating the surfaces at which light ts refracted in the 
eyo, 


by observing that we cannot see distinctly, at the same 
moment, both near and distant objects. For example 
standing at a window hind a lace curtain, we can if we 
eads of the lace or the houses across 

look at the one we only see the 

after looking at the more distant 

re experience a distinet sense 

n, that something in the eye is 

‘The resting eye, suited for dis- 

tinctly seeing r ght conceivably be accom- 
modated for near vision in several ways. The refracting 





ACCOMMODATION. 490 


indides of its media might be increased; that of course does 
not happen; the physical properties of the media are the 
same in both cases: or the distance of the retina from 
the refracting surfaces might be increased, for example by 
compression of the eyeball by the muscles around it; how- 
ever, experiment shows that changes of accommodation can 
be brought about in the fresh excised eyes of animals, in 
which no such compression is possible; we are thus reduced 
to the third explanation, that the refracting surfaces, or 
some of them, become more curved, and so bring more 
diverging rays sooner to a focus; since a lens of smaller 
curvature is more converging than one of greater curvature 
composed of the same material. Observation shows that 
this is what actually happens: the corneal surface remains 
unchanged when a near object is looked at 
after a distant one, but the anterior sur- 
face of the lens becomes considerably more 
convex and the posterior slightly so. As 
already pointed out when light meets the 
separating surface of two media some is 
reflected and some refracted (p. 493). If, 
therefore, a person be taken into a dark 
room and a candle held on one side of his 
eye, while he looks at a distant object an 
observer can see three images of its flame 
in his pupil, due to that part of the light 
reflected from the surfaces between the media. One (a, 
Fig. 152) is erect and bright, reflected from the convex 
mirror formed by the cornea; the next, d, is dimmer and also 
erect; it comes from the front of the lens. The third, ¢, 
is dim and inverted, being reflected from the concave mirror 
(see Physics) formed by the back of the lens. If now the 
observed eye looks at a near object in the same line as the 
distant point previously looked at, it is seen that the image 
due to corneal reflection remains unchanged; that due to 
light from the front of the lens becomes smaller and brighter, 
indicating (see Physics) a greater convoxity of the reflecting 
surface; the image from the back of the lens also becomes very 
slightly smaller, indicating a feebly increased curvature, 





500 THE HUMAN BODY. 


Accommodation is brought about mainly by the ciliary 

muscle. In the resting eye it is relaxed and the suspensory 

ligament of the lens is taut, and, pulling on its edge, drags 

it out laterally # little and flattens its sarfaces, especially 

the anterior, since the ligament is attached a little in front 

of the edge. To see a nearer object the ciliary muscle is 

contracted, and according to the degree of its contraction 

slackens the suspensory ligament (p. 491), and then the 

elastic lens, relieved from the lateral drag, bulges ont a 
little in the centre, 

Short Sight and Long Sight. In the eye the range of 

accommodation is very great, allowing the rays from points 

infinitely distant up to those 

from points about eight inches 

in front of the eye to be 

brought toa focus on the re- 

tins, In the normal eye par- 

allel rays meet on the retina 

when the ciliary muscle is 

completely relaxed (A, Fig. 

133). Such eyes are emme- 

tropic. In other eyes the eye- 

ball 1s too long from before 

back; in the resting state par- 

raropio (8) allel rays meet in front of the 

and pps 8 (0) 4 retina( 8). Persons with such 

rence distant objects diatanoety without 


the resting state, parallel rays are 
ind the retins (0). To see even 
, such persons must therefore use 
pps tus to increase the converging 
1 objects ane near they cannot, 
divergent rays proceeding 
igh. ‘To get distinct rotinal 
erefore need converging. (ee 

are called Aypermetropic, or 





HYGIENE OF THE BYR. 501 


Hygienic Remarks. Since muscular effort is needed by 
the normal eye to see near objects, it is clear why the pro- 
longed contemplation of such is more fatiguing than look- 
ing at more distant things. If the eye be hypermetropic still 
more is this apt to be the case, for then the ciliary muscle 
has no rest when the eye is used, and to read a book at a 
distance such that enough light is reflected from it into the 
eye in order to enable the letters to be seen at all, requires 
an extraordinary effort of accommodation. Such persons 
complain that they can read well enough for a time, but 
soon fail to be able to see distinctly. This kind of weak 
sight should always lead to examination of the eyes by an 
oculist, to see if glasses are needed; otherwise severe neu- 
ralgic pains about the eyes are apt to come on, and the 
overstrained organ may be permanently injured. Old per- 
sons are apt to have such eyes; but young childen frequently 
also possess them, and if so should at once be provided 
with spectacles. 

Short-sighted eyes appear to be much more common now 
than formerly, especially in those given to literary pursuits. 
Myopia is rare among those who cannot read or who live 
mainly out of doors. It is not so apt to lead to per- 
manent injury of the eye as is the opposite condition, but 
the effort to see distinctly objects a little distant is apt 
to produce headaches and other symptoms of nervous 
exhaustion. If the myopia become gradually worse the 
eyes should be rested for several months. Short-sighted 
persons are apt to have, or acquire, peculiarities of appear- 
ance: their eyes are often prominent, indicative of the 
abnormal length of the eyeball. They also get a habit of 
“serowing” up the eyelids, probably an indication of an 
offort to compress the eyeball from before back so that 
distant objects may be better seen. They often stoop, too, 
from the necessity of gotting their eyes near objects they 
want to see, The aequirement of such habits may be 
usually prevented by the use of proper glasses. On the 
other hand “it is said that myopia even induces poculiari- 
ties of character, and that myopes are usually unsuspicions 
and easily pleased; being unable to observe many little 





502 THE HUMAN BODY. 


matters in the demeanor or expression of those with 
whom they converse, which, being noticed by those of 
quicker sight, might induce feelings of distrust or annoy- 
ance.” 

In old age the eyeball tends to become flattened; hence 
emmetropic eyes become hypermetropic and old persons 
are usually “ long-sighted ” and need convex glasses. Such 
a flattening of the eyeball is of course a relief to the 
myopic eye; and so short-sighted persons can frequently, 
when old, still read withont glasses. But this is poor com~ 
pensation for the mistiness with which everything around 
them, except very near objects, has been seen throughout 
their previous life. 

In all forms of deficient accommodation too strong glasses 
will injure the eyes irreparably, increasing the defects 
they are intended to relieve, Skilled advice should there 
fore be invariably obtained in their selection, except per- 
haps in the long-sightedness of old age when the sufferer 
may tolerably safely select for himself any glasses that 
allow him to read easily a book about 30 centimeters (12 
inches) from the As ago advances stronger lenses 
must of course be obtained. 

Optical Dofects of the Eye, The eye, though it an- 
swars admirably as a physiological instrument, is by no 
means perfect optically; not nearly so good, for example, 
as a good microscope objective. The main defects in it are 


matic Aberration. As already pointed out the 

violet end of the solar spectrum are more re- 

frangible than those at the red end. Hence they are 
brought toa foor s The light emanating from # 
point ona white o es not, therefore, all meet in one 
vlet rays come toa focus first, 

to the red, farthest back of all. 

d so as to bring to a focus on the 

iolet rays from the same 

ter in front of it, and cross- 

a little violet circle of diffu. 

Tn optical instra~ 





OPTICAL DEFECTS OF THE EYE. 503 


ments this defect is remedied by combining together lenses 
made of different kinds of glass; such compound lenses 
are called achromatic, 

‘The general result of chromatic aberration, as may be 
seen in a bad opera-glass, is to cauze colored borders to ap- 
pear around the edges of the images of objects. In the eye 
we usually do not notice such borders unless we especially 
look for them; but if, while a white surface is looked 
at, the edge of an opaque body be brought in front of the 
eye xo as to cover half the pupil, colorations will be seen 
at its margin. If accommodation is inexact they appear 
also when the boundary between a white and a black sur- 
face ig observed. The phenomena due to chromatic 
aberration are much more easily seen if light containing 
only red and violet rays be nsed instead of white light con- 
taining all the rays of intermediate refrangibility, Ordi- 
dinary blue glass only lets through these two kinds of rays. 
If a bit of it be placed over a very small hole in an opaque 
shutter and the sunlight be suffered to enter through the 
hole, it will be found that with one accommodation (that 
for the red rays) a red point is seen with a violet border, 
and with another (that at which violet rays are brought to 
a focus on the retina) a violet point is seen with a red 
aureole, 

2. Spherical Aborration. Tt is not quite correct to state 
that ordinary lenses bring to a focus in one point behind 
them rays proceeding froma point in front, even when these 
are all of the same refrangibility. Convex lenses whose 
surfaces are segments of spheres, as are those of the eye, 
bring to a focus sooner the rays which pass through their 
marginal than those through their central parts. If tho 
rays proceeding from a point and traversing the lateral 
part of a lens be bronght to a focns at any point, then 
those passing through the centre of the lens will not meet 
until a little beyond that point. If the retina receive the 
image formed by the peripheral rays the others will form 
around this asmall luminous circle of light—snch as would 
be formed by sections of the cones of converging rays in Fig, 
122, taken a little in frontof rr. ‘This defect is found in all 








OPTICAL DEFECTS OF THE RYE. 505 


minute bodies floating in space outside the eye, but chang- 
ing their position when the position of the eye ae 
by which fact their origin in interral causes may be 

nized. Many persons never see them until their attention 
is called to their sight by some weakness of it, and then 
they think they are new phenomena. Visual phenomena 
due to causes in the eye itself are called enfoptic; the most 
interesting are those due to the retinal blood-vessels (Chap. 
XXXIL). Tears, or bits of the secretion of the Meibo- 
mian glands, on the front of the eyeball often cause distant 
luminous objects to look like ill-defined luminous bands or 
patches of various shape. The cause of such appearances is 
readily recognized, since they disappear or are changed 
after winking, 





CHAPTER XXXII. 


THE EYE AS A SENSORY APPARATUS, 


The Excitation of the Visual Apparatus. The excita- 
ble visual apparatus for each eye consists of the retina, the 
optic nerve, und the brain-centres connected with the latter; 
however stimulated, if intact, it causes visual sensations. In 
the great majority of cases its excitant is objective light, 
and so we refer all stimulations of it to that cause, unless 
we have special reason to know the contrary. As already 
pointed out (p. 468) pressure on the eyeball causes « lumi- 
nous sensation (phosphene), which suggests itself to us 
‘as dependent on aluminous body situated in space where 
euch an object must be in order to excite the same purt of 
the retina. Since all rays of light penetrating the eye, 
except in the line of its long axis, cross that axis, if 
we press the outer side of the eyeball we get a visual sensa- 
tion referred to a luminous body on the nasal side; if we 
press below we see the luminous patch above, and so on, 

Of course different rays entering the eye take different 
paths through it, but on general optical principles, which 
cannot here be detailed, we may trace all oblique rays 
through the organ by assuming that they meet and leave 
the optic axis at what are known as the nodal points of 
the system; these (&k', Fig. 135) lie near together in 
the lens. If we want to find where rays of light from A 

i (the eye being properly accommodated 

q & that distance) we draw a line from 

int) and then another, parallel to 

nd nodal point) to the retina, 

lie so near together that for 

Irposes we may “treat them as one (&, Fig. 186), 




















. 

POSITION OF RETINAL IMAGES. 507 
placed near the back of the lens. By manifold experience 
we have learnt that a luminous body (4 Fig. 136) which we 


soe, always lies on the prolongation of the line joining the 
excited part of the retina, a, and the nodal point, &, Hence 


B 


uny excitation of that part of the retina makes us think of a 
luminous body somewhere on the line @ A, and, similarly, 
any excitation of 0, of a body on the line 4 B or its pro- 
longation. It is only other conflicting experiences, as that 


soli pit Pimerammatic section through the eyeball 2, optic axing & 
with the eyes closed external bodies do not excite visual 
sensations, and the constant connection of the pressure felt 
on the eyelid with the visual sensation, that enable ug 
when we press the eyeball to conclude that, in spite of what 








508 THE HUMAN BODY. 


we seem to see, the luminous sensation is not due to objective 
light from outside the eye. 

The Idio-Retinal Light. The eyelids are not by any 
means perfectly opaque; in ordinary daylight they still allow 
a considerable quantity of light to penetrate the eye, as any 
one may observe by passing his hand in front of the closed 
eyes. But even ina dark room with the eyes completely 
covered up so that no objective light can enter them, there 
is still experienced asmall amount of visual sensation due to 
internal causes. The field of vision is not absolutely dark 
but slightly luminous, with brighter fleeting patches tray- 
ersing it. These are especially noticeable, for example, in 
i see and grope one’s way with the eyes open up a 
ly dark staircase, ‘Then the luminous patches attract 
attention because they are apt to be taken for the 
of objective realities; they become very manifest when 
any sudden jar of the Body, due for example to knocking 
against something, occurs; and have no doubt given rise to 
many ghost stories, ‘These visual sensations felt in the 
absence of all external stimulation of the eyes, may for con- 
yenience be spoken of as due to the idio-retinal light, 

The Excitation of the Visual Apparatus by Light. 
Light only excites the retina when it reaches its nerve end 











Fro. 127, 


organs, the rods an@ cones. The proofs of this are several. 

1. Light does not arouse visual sensations when tt falls 
directly on the fibres of the optic nerve. Where this nerve 
enters (p. 490) is a retinal part possessing only nerve-fibres, 
and this part is blind. Close the left eye and look steadily 
with the right at the cross in Fig. 137, holding the book 


FUNCTION OF RODS AND CONES, 509 


vertically in front of the face, and moving it to and fro. 
It will be found that at about 25 centimeters (10 inches) 
off the white circle disappears; but when the page is nearer 
or farther, it is seen. During the experiment the gaze must 
be kept fixed.on the cross. There is thus in the field of 
vision a dlind spot, and it is easy to show by measurement 
that it lies where the optic nerve centres. 

When the right eyo is fixed on the cross, it is so directed 
that rays from this fall on the yellow spot, y, Fig. 138, 
The rays from the circle then cross the visual axis at the 
nodal point, n, and meet the retina at 0. 

If the distance of the eye from the paper be i. 
be f, and that of the nodal point from the 

retina (which is 16 mm.) be F, then the dis- 

tance, on the paper, of the cross from the 

circle will be to the distance of y from o as 

f is to F Measurements made in this 

way show that the circle disappears when 

its image is thrown on the entry of the 

optic nerve, which lies to the nasal side of 

the yellow spot (p. 487). 

2. The above experiment having shown 
that light does not act directly on the 
optic nerve-fibres any more than it does 
on any other nerve-fibres, we have next to 
see in what part of the retina those changes 
do first oceur which form the link between 
light and nervous impulses. They oceur in ean 
the outer part of the retina, in the rods and cones, This is 
proved by what is called Parkinje’s experiment. Take a 
candle into a dark room and look at a surface not covered 
with any special pattern, say a whitewashed wall or a plain 
window-shade. Hold the candle to the side of one eye and 
close to it, but so far back that no light enters the pupil 
from it; that is so far back that the flame just cannot be 
seen, but so that a strong light is thrown on the white of 
the eye as far back as possible, Then move the candle a 
little to and fro. The surface looked at will appear 
luminous with reddish-yellow light, and on it will be seen 





THE HUMAN BODY. 


dark branching lines which are the shadows of the retinal 
vessels. Now in order that these shadows may be seen the 
parts on which the light acts must be behind them, and 
therefore in the outer layers of the retina since the es 
lie (p. 490) in its inner strata. 

If the light is kept steady the vascular shudows oa 
appear; in order to continue to see them the candle must 
be kept moving. The explanation of this fact may readily 
be made clear by fixing the eyes for ten or fifteen seconds 
on the dot of an “i” somewhere abont the middle of this 
page: at first the distinction between the slightly luminons 
black letters and the highly luminous white page is very 
obvious; in other words, the different sensations arising 
from the strongly and the feebly excited areas of the retina. 
But if the glance do not be allowed to wander, very soon 
the letters become indistinct and at last disappear 
altogether; the whole page looks uniformly grayish. The 
reason of this is that the powerful stimulation of the retina 
by the light reflected from the white part of the page soon 
fatigues the part of the visual apparatus it acts upon; and as 
this fatigue progresses the stimulus produces less and less 
effect, The parts of the retina, on the other hand, which 
receive light only from the black letters are very little stimu- 
lated and retain their original excitability so that, at last, 
the feebler excitation acting upon these more irritable parts 
prodaces as much sensation as the stronger stimulus acting 
upon the fatigued parts; and the letters become indistin- 
guishable. ‘To see them continuously we must keep shift- 
ing the eyes so that the same parts of the visual apparatus 
are alternately fatigued and rested, and the general irrita- 
bility of the whole is kept about the same. So, in 


than the more excited unshaded 
irritability makes up for 
Bek the shadows cease to be 





PURKINSES EXPERIMENT, wa 


shadows always protect the same parts of the retina, and 
these parts are thus keptsufficiently more excitable than the 
rest to make up for the less light reaching them through 
the vessels. ‘To see the latter we must throw the light into 
the eye in an unusual direction, not through the pupil but 
laterally through the sclerotic. If », Fig. 139, be the 
section of a retinal vessel, ordi- is e 
narily its shadow will fall at = 
some point on the line prolonged Gy 
through it from the centre of 
the pupil. Ifa candle be held 
opposite b it illuminates that 
part of the sclerotic and from 
there light radiates and illumines 
the eye. The sensation we refer 
to light entering the eye in the 
usual manner through the pupil, 
and accordingly see the surface 
we look at as if it were illuminated. The shadow of w is 
now east on an unusual spot ¢, and we see it as if at the point 
don the wall, on the prolongation of the line joining the 
nodal point, &, of the eye with c. If the candle be moved 
80 as to illuminate the point 4’ of the sclerotic, the shadow 
of v will be cast on ec’ and will accordingly seem on the 
wall to move from d tod’. It is clear that if we know how 
far bis from 6‘, how far the wall is from the eye, and how 
far the nodal point is from the retina (15 mm. or 0.6 inch), 
and measure the distance on the wall from d to d’, we can 
caleulate how far ¢ is from ¢’: and then how far the vessel 
throwing the shadow must be in front of the retinal parts 
perceiving it. In this way it is found that the part seeing 
the shadow, that is the layer on which light acts, is just 
about as far behind the retinal vessels as the main vascular 
trunks of the retina are in front of the rod and cone layer, 
Tt is, therefore, in that layer that the light initiates those 
changes which give rise to nervous impulses; which is 
further made obvions by the fact that the seat of most 
acute vision is the fovea centralis, where this layer and the 
cone-fibres diverging from it alone are found (p. 490). 


Fra, 1%, 





512 THE HUMAN BODY. 


When we want to sce anything distinctly we always turn 
our eyes so that its image shall fall on the centre of the 
yellow spot. 

Tho Vision Purple. How light acts in theretina so as to 
produce nerve stimuli is still uncertain, Recent observa- 
tions show that it produces chemical changes in therod and 
cone layer, and seemed at first to indicate that its action 
was to produce substances which were chomical excitants 
of nerve-fibres; but although there can be little doubt that 
these chemical changes play some important part in vision, 
what their rile may be is at present quite obscure. If a 
perfectly fresh retina be excised rapidly, its outer layers 
will be found of a rich purple color. In daylight this 
rapidly bleaches, but in the dark persists even when putre- 
faction has set in. In pure yellow light it also remains 
unbleached a long time, but in other lights disappears at 
different rates. If a rabbit’s eye be fixed immovably and 
exposed so that an image of a window is focused on the 
same part of its retina for some time, and then the eye be 
rapidly excised in the dark and placed in solution of potash 
alum, a colorless image of the window is fonnd on the 
retina, surrounded by the visual purple of the rest which 
is, through the alum, fixed or rendered incapable of change 

or optograms, are thus obtained 
photogrepher's in that he uses light 

nges which give rise to eolored 

is the case. If the eye be 

in the alam after its exposure, 

he vision purple being rapidly 

leached part. This reproduction of it 
the cel alls © pigmentary layer of the 
aised from this bleach 

tact with it, but become 





VISION PURPLE. ‘518 


within their reach; and they can also distinguish colors, or 
at least some colors, as green. Moreover, the vision purple 
is only found in the outer segments of the rods; there is 
none in the cones, and yet these alone exist in the yellow 
spot of the human eye, which is the seat of most acute 
vision; and animals, such as snakes, which have only cones 
in the retina, possess no vision purple and nevertheless see 
very well. 

It may be that other bodies exist in the retina which are 
also chemically changed by light, but the changes of which 
are not accompanied by alterations in color which we can 
see; and in the absence of the vision purple seeing might be 
carried on by means of these, which may be less quickly 
destroyed by light and so still persist in the bleached 
retinas of the frogs above mentioned. For the present, 
however, the question of the part, if any, played in vision 
by such bodies must be left an open one. 

‘The Intensity of Visual Sensations. Light considered 
asa form of energy may vary in quantity; physiologically, 
also, we distinguish quantitative differences in light as 
degrees of brightness, but the connection between the in- 
tensity of the sensation excited and the quantity of energy 
represented by the stimulating light is not a direct one. 
In the first place some rays excite our visual apparatus 
more powerfully than others; a given amount of energy in 
the form of yellow light, for example, causes more powerful 
visual sensations than the same quantity of energy in the 
form of violet light. The ultra-violet rays only become 
visible, and then very faintly, when all others are suppressed; 
bat if they be passed through some fluorescent substance 
(see Physics), such as an acid solution of quinine sulphate, 
which, without altering the amount of energy, turns it into 
ethereal oscillations of a longer period, then the light be- 
comes readibly perceptible. 

Even with light-rays of the same oscillation period our 
sensation is not proportioned to the amount of energy in 
the light; to the amount of heat, for example, to which it 
would give rise if all transformed into it. If objective 
light increase gradually in amount our sensation increases 





oid THE HUMAN BODY, 


also, up toa limit beyond which it does not go, no matter 
how strong the light becomes; but the increase of sensation 
takes place far more slowly than that of the light,in accord- 
wnce with the psycho-physical law mentioned on page 473. 
If we call the amount of light given out by a single candle 
a, then that emitted by two candles will be 2a; and so on. 
If the amount of sensation excited by the single candle be 
A, then that due to two candles will not be 24, and that 
by three will be far Icss than 34. Ifa white surface, P, 
Fig. 140, be illuminated by a candle at c and another else 
where, and a rod, 0, be placed 
so as to intercept the light 
from c, we see clearly « shadow, 
since our eyes recognize the 
difference in Inminosity of 
this part of the paper, reflect- 
ing light from one candle only, 
from that of the rest which is illuminated by two: that is 
we tell the sensation due to the stimulus a from that due 
to the stimulus 24. If now a bright lamp be brought in 
and placed alongside, and its light be physically equal to 
that of 10 candles, we cease to perceive the shadow 4, 
That is the sensation aroused by objective light = 12a 
(due to the lamp and two candles) cannot be told from that 
due to light = lla; although the difference of objective 
light is la a8 before. Most persons must have ob- 
served illustrations of this. Sitting in a room with three 
lights not unfroquently some object so intercepts the light 
from two as to cast on the wall two shadows which partly 
overlay ere the shadows Sets the wall shi light 


ce 


Fro, 140. 


nighborhood of the shadows by ail 
‘ore, the difference between the 

0 low is that between the light 

of one candle ani wo. The difference between 
the half shade around is that between the 
Hight of two and three candles. But as a matter of sensa- 
® the difference be! the half shadow and the full 





INTENSITY OF VISUAL SENSATIONS. 515 


shadow seems much greater than that between the half 
shadow and the rest of the wall; in other words the differ- 
ence, a, between a and 2a, is a more efficient stimulus than 
the samo difference, a, between 24 and 34, When the 
total stimulus increases the same absolute difference is less 
felt or may be entirely unperceived. An example of this 
which every one will recognize is afforded by the invisibility 
of the stars in daytime, 

On the other hand, as the total stimulus increases or de- 
creases the same fractional difference of the whole is per- 
ceived with the game ease; #e. excites the same amount 
of sensation. In reading a book by lamplight we perceive 
clearly the difference between the amount of light reflected 
from the black letters and the white page. If we call the 
total lamplight reflected by the blank parts 10a and that 
by the letters 2a, we may say we perceive with a certain 
distinctness a luminous difference equal to one fifth of 
the whole. If we now take the book into the daylight the 
total light reflected from both the letters and the unprinted 
part of the page increases, but in the same proportion. Say 
the one now is 50¢ and the other 10a; although the 
absolute difference between the two is now 40a instead of 
8a we do not see the letters any more plainly than before. 
The smallest difference in luminous intensity which we 
can perceive is about yh, of the whole, for all the range of 
lights we use im carrying on our ordinary occupations. 
For strong lights the smallest perceptible fraction is con- 
siderably greater; finally we reach a limit where no increase 
in brightness is felt. For weak illumination the sensation 
is more nearly proportioned to the total differences of the 
objective ight. Thus in a dark room an object reflecting 
all the little light that reaches it appears almost twice as 
bright as one reflecting only half; which in a stronger 
light it would not do. Bright objects in general obscurity 
thus appear unnaturally bright when compared with things 
about them, and indeed often look self-luaminous. A cat’s 
eyes, for example, are said to “shine in the dark;” and 
painters to produce moonlight effects always make the 
bright parts of a picture relatively brighter, when compared 





516 THE HUMAN BODY, 


with things about them, than would be the case if a sunny 
scene were to be represented; by an excessive use of white 
pigment they produce the relatively great brightness of 
those things which are seen at all in the general obscurity 
of a moonlight landscape. 

‘The Duration of Luminous Sensations. This is greater 
than that of the stimulus, a fact taken advantage of in 
making fireworks: an ascending rocket produces the sen- 
sation of a trail of light extending far behind the position 
of the bright part of the rocket itself at the moment, 
because the sensation aroused by it in a lower part 
of its course still persists. So, shooting stars appear to 
have luminous tails behind them. By rotating rapidly 
before the eye a disk with alternate white and black sectors 
wo get for each point of the retina on which a part of ite 
image falls, alternating stimulation (due to the passage of 
white sector) and rest, when « black sector is passing. If 
the rotation be rapid enough the sensation aronsed is that 
of a uniform gray, ench as would be produced if the white 
and black were mixed and spread evenly over the disk. 
In each revolution the eye gets as much light as if that 
were the case, and is unable to distinguish that this light is 
made up of separate portions reaching it at intervals: the 

to cach lasts until the next begins and 20 
gether. If one turns out suddenly the gas 


‘y condition of seeing definite ob- 
m the power of recognizing dif 
knees, is that all light entering 

object shall be focused on one 
jowever, would not be of any 
stinguishing the stimula- 





LOCALIZING POWER OF RETINA. or 


are not more than .004 mm. (,00016 inch) apart, The 
distance between the retinal images of two points is deter- 
mined by the ‘‘visual angle” under which they are seen; 
this angle is that incladed betweeu lines drawn from them 
to the nodal point of the eye. Ifa and d (Fig. 141) are 


et 


two points, the image of a will be formed at a on the pro- 
longation of the line a n joining a with the node, x. Sim- 
ilarly the image of } will be formed at &. If a and 3 still 
remaining the same distance apart, be moved nearer the 
eye tocand d,then the visnal angle under which they are seen 
will be greater and their retinal images will be farther apart, 
ate andd’. Ifaand dare the highest and lowest parts 
of un object, the distance between their retinal images will 
then depend, clearly, not only on the size of the object, but 
on its distance from the eye; to know the discriminating 
power of the retina we must therefore measure the visual 
angle in each case, In the fovea centralis two objects seon 
under a visual angle of 50 to 70 seconds can be distinguished 
from one another: this gives for the distance between the 
retinal images that above mentioned, and corresponds 
pretty accurately to the diameter of a cone in that part of 
the retina. We may conclude, therefore, that when two 
images fall on the same cone or on two contiguous cones 
they are not discriminated; but that if one or more un- 
stimulated cones intervene between the stimulated, the 
points may be perceived as distinct. The diameter of a 
rod orcone, in fact, marks the anatomical limit up to which 
we can by practice raise our acuteness of visnal discrimina- 
tion; and in the yellow spot which we constantly use all 
our lives in looking at things which we want to see dis- 
tinctly, we have educated tho visual apparatus up to about 





520 THE HUMAN BODY. 


to white: or beginning with green through darker and 
darker shades of it to black or through lighter and lighter 
to white: or beginning with red we can by imperceptible 
steps pass to orange, from that to yellow and go on to the 
end of the solar spectrum: and from the violet, through 
purple and carmine, we may get back again to red. Black 
und white appear to be fundamental color sensations mixed 
up with all the rest: we neyer imagine a color but as light 
or dark, that is as more or less near white or black; and 
it is found that asthe light thrown on any given colored sur- 
face weakens, the shade becomes deeper until it passes into 
black; and if the illumination is increased, the color 
becomes “lighter” until it passes into white. Of all the 
colors of the spectrum yellow most easily passes into white 
with strong illumination, Black and white, with the grays 
which are mixtures of the two, thus seem to stand spart 
from all the rest as the fundamental visual sensstions, and 
the others alone are in common parlance named “colors.” 
Tt has even been suggested that the power of differentiating 
them in sensation has only lately been acquired by man, 
and « certain amount of evidence has been adduced from 
passages in the Iliad to prove that the Grecks in Homer's 
time confused together colors that are very different to most 
modern eyes; at any rate there seems to be no doubt that 
the color sense can be greatly improved by practice; women 
whose mode of dress causes them to pay more attention to 
the matter, have, as 4 general rule, « more acute color sense 


of other colors), wo may enum- 
aa red, orange, yellow, green, blue, 
.each there are, however, numer- 
w-green, blue-green, ete, 80 


Of the above, all but 
um given when sunlight is 


h or period of oscillation cause in 
w, and so on; forconvenience 





COLOR VISION. 521 


we may speak of these as red, yellow, blue, ete., rays; all 
together, in about equal proportions, they arouse the sen- 
sation of white. A remarkable fact is that most color feel- 
ings can be aroused in several ways. White, for example, 
not only by the above general mixture, but red and blue- 
green rays, or orange and blue, or yellow and violet, taken 
together in pairs, cause the sensution of white: such colors 
are called complementary to one another. The mixture 
may be made in several ways; as, for example, by causing 
the red and blue-green parts of the spectrum to overlap, or 
hy painting red and blue-green sectors on a disk and 
rotating it rapidly; they cannot be made, however, by mix- 
ing pigments, since what happens in such cases is a very 
complex phenomenon. Painters, for example, are accus- 
tomed to produce green by mixing blue and yellow paints, 
and some may be inclined to ridicule the statement that yel- 
Jowand blue when mixed give white. When, however, we 
mix the pigments we do not combine the sensations of 
the same namo, which is the matter in hand. Blue paint 
ia blue because it absorbs all the rays of tho sunlight except 
the blue and some of the green; yellow is yellow because it 
absorbs all but the yellow and some of the green, and when 
blue and yellow are mixed the blue absorbs all the distinc- 
tive part of the yellow and the yellow does the same for the 
blue; and so only the green is left over to reflect light to 
the eye, and the mixture has that color. Grass-green has 
no complementary color in the solar spectram; but with 
purple, which is made by mixing red and blue, it gives 
white. Several other colors taken three together, give also 
the sensation of white. If then we call the light-rays 
which arouse in us the sensation red, a, those giving us 
the sensation orange }, yellow c, and so on, we find that we 
get the sensation white with a, 0, ¢, d,¢, fand gall together; 
or with d and ¢, or with ¢ and f, or with a, d, and e; our 
sensition white has no determinate relation to ethereal 
oscillations of a given period, and the same is true for 
several other colors; yellow feeling, for example, may be 
excited by ethereal vibrations of one given wave-length 
(spectral yellow), or by mixing red and grass-green, which 





522 THE HUMAN BODY. 


are due to ethereal vibrations of totally different wave- 
lengths; in other words a physical light in which there are 
no waves of the “yellow” length may cause in us the sen- 
sation yellow, which is only one more instance of the gen- 
eral fact that our sensations, as such, give na no direct 
information as to the nature of external forces; they are 
but signs which we have to interpret. The modern view of 
specific nerve energies (p. 191) makes it highly improbable 
that our different color sensations can all be due to different 
modes of excitation of exactly the same nerve-fibres; a fibre 
which when excited alone gives us the sensation red will 
always give us that feeling when so excited. ‘The simplest 
method of explaining our color sensations would therefore 
be to assume that for each there exists in the retina o set 
of nerve-fibres with appropriate terminal organs, each ex- 
citable by its own proper stimulus. But we can distinguish 
so innumerable and so finely graded colors, that, on such a 
supposition, there must be an almost infinite number of 
different end organs in the retina, and it is more reasonable 
to suppose that there are a limited number of primary color 
sensations, and that the rest are due to combinations of these. 
‘That a compound color sensation may be very different 
from its components when these are regarded apart, is 
jown by the sensation white aroused either by 

nay call red and blue-green, or green and purple, 

ther; or of yellow due to grass-green and 

t for ow ‘various color sensations we may, 


nber of color sensations we expe- 
explained by assuming any three 
hich together give white, and 
mixtures of these in various 


uli are absent. This is 
vision, and is that at 
The selection of the 
arbitrary, but fee 





COLOR BLINDNESS. 523 


assumed that all kinds of light stimulating the end appa- 
ratuses give rise to all three sensations, but not necessarily 
in the same proportion. When all are equally aroused the 
sencation is white; when the red and green are tolerably 
powerfully excited and the violet little, the sensation is 
yellow; when the green powerfully and the red and violet 
little, the sensation is green, and so on. In this way we 
can also explain the fact that all colored surfaces when 
intensely illuminated pass into white. A red light, for 
example, excites the primary red sensation most, but green 
and violet a little; as the light becomes stronger a limit is 
reached beyond which the red sensation cannot go, but the 
green and violet go on increasing with the intensity of the 
light, until they too reach their limits; and all three pri- 
mary sensations being then equally aroused, the sensation 
white is produced. 

Color Blindness. Some persons fail to distinguish colors 
which are to others quite different; when such a de- 
ficiency is well marked it is known as “color blindness,” 
and, assuming Young’s theory to be correct, it may be ex- 
plained by an absence of one or more of the three primary 
color sensations; observation of color-blind persons thus 
helps in deciding which these are. The most common 
form is red color blindness; persons afflicted with it con- 
fuse reds and greens. Red to the normal eye is red because 
it excites red sensation much, green some, and violet 
less; and a white page white, because it excites red, green, 
and violet sensations about equally. In a person without 
red sensation a red object would arouse only some green 
and violet sensation and so would be indistinguishable from 
a bluish green; in practice it is found that many persons 
confound these colors. Cases of green and violet color 
blindness are also met with, but they are much rarer than 
the red color blindness or * Daltonism.” 

‘The detection of color blindness is often a matter of con- 
siderable importance, especially in sailors and railroad 
officials, since the two colors most commonly confounded, 
red and green, are those used in maritime and railroad 
signals, Persons attach such different names to colors that 





a decision as to color blindness cannot be safely arriven at 
by simply showing a color and asking its name. The best 
plan is to take a heap of worsted of all tints, select one, 
say a red, and tell the man to put alongside it all those | 
the same color, whether of a lighter or a darker shade; 1 
red blind he will select not only the reds but the greens, 
especially the paler tints. About one man in eight is red 
blind. The defect is much rarer in women. 
Fatigue of the Retina, The nervous visual apparatus 
is easily fatigued. Usually we do not observe this be- 
cause its restoration is also rapid, and in ordinary life our 
eyes, when open, are never at rest; we move them to and 
fro, so that parts of the retina receive light alternately 
from brighter and darker objects and are alternately excited 
and rested. How constant and habitual the movement of 
the eyes is can be readily observed by trying to fix fora 
short time a small spot without deviating the glance; to 
do so for even a few seconds is impossible withont practice. 
If any small object is steadily * fixed” for twenty or 
thirty seconds it will be found that the whole field of 
vision becomes grayish and obscure, because the parts of 
the retina receiving most light get fatigued, and aronse 
no more sensation than those less fatigued and stimulated 
by light from less illuminated objects. Or look steadily at 
a black object, say a blot on a white page, for twenty 
seconds, and then turn the eye on a white wall; the latter 
will seem ith a white patch on it; an effect 
due to the great itability of the retinal parts previously 
the black, when compared with the sensation 
ight from the white wall acting on 
ted parts of the visual surface, 


¢ noticed with colors; after 
‘arned on a white wail sees 


retina only the other 
ing of colors so as to 








COLOR CONTRASTS. 525 


secure their greatest effect depends on this fact; red and 
green go well together because each rests the parts of the 
visual apparatus most excited by the other, and so each 
appears bright and vivid as the eye wanders to and fro; 
while red and orange together, each exciting and exhaust- 
ing mainly the same visual elements, render dull, or in 
popular phrase “ kill,” one another. 

Contrasts. If awell-defined black surface be looked at on 
a lerger white one the parts of the latter close to the bluck 
look whiter than the rest, and the parts of the black near 
the white blacker than the rest; so, also, if a green patch be 
looked at on a red surface each color is heightened near 
where they meet. This phenomenon is largely due to fatigue 
and deficient fixation: a region of the eye rested by the 
black or the green is brought by a movement of the organ 
so us to receive light from the white or red surface; phe- 
nomena due to this cause are known as those of successive 
contrast, Even in the case of perfect fixation, however, 
something of the same kind is seen; black looks blacker 
near white, and green greener near red when the eye has not 
moved in the least from one to the other. A small piece of 
light gray paper put on a sheet of red, which latter is 
then covered accurately with a sheet of semi-transparent 
tissue-paper, assumes the complementary color of the red, 
té. looks bluish green; and gray on a green sheet under 
similar circumstances looks pink. Such phenomena are 
known a3 those of simultaneous contrast, and are explained 
on psychological grounds by those who accept Young’s 
theory of color vision. Just a8 a medium-sized man looks 
short beside a tall one, 80, it is said, a black surface looks 
blacker near a white one, or a gray (slightly luminous 
white) surface, which fecbly excites red, green, and violet 
sensations, looks deficient in red (and so bluish green) 
near a deeper red surface. here are, however, certain 
phenomena of simultaneous contrast which cannot be satix- 
factorily so explained, and these have led to other theories 
of color vision, the most important of which is that de- 
scribed in the next paragraph. 

Horing’s Theory of Vision. Contrasts can be seen with 





the eyes closed and covered. If we look a sexes 
bright object and then rapidly exclude eee the eye, 
we sce for 8 moment a positive after-image of 
e.g. & window with its frame and panes after a glance at it 
aud then closing the eyes. In these positive after-images 
the bright and dark parts of the object which was looked at 
retain their original relationship; they depend on the persist- 
ence of retinal excitement after the cessation of the stimulus 
and usually soon disappear. If an object be looked at 
steadily for some time, say twenty seconds, and the eyes be 
then closed a negative after-image is seen. In this the lights 
and shades of the object looked at are reversed. 
4 positive after-image becomes negative before di 
‘The negative images are explained commonly by fatigue; 
when the eye is closed some light still enters through the 
lids and excites less those parts of the retina previously 
exhausted by prolonged looking at the brighter parts of the 
field of vision: or, when all light is rigorously excluded, the 
proper stimulation of the visual apparatus itself, causing 
the idio-retinal light, affects less the exhausted portions, and 
so a negative image is produced. If we fix steadily for 
thirty seconds a point between two white squares about 4 
mm. (} ch) apart on a large black sheet, and then close 
and cover our eyes, we get a negative after-image in which are 
seen two dar! squares on a brighter surface; this surface is 
| the negative after-image of each square, 
een them. ‘This laminous bound- 
nd is explained usually as an effect 
he dark after-image of the square 


Brighter than elsewhere; and it is 
two dark squares, jnet as a middle- 
ones looks shorter than if along- 
the fter-image be watched it 

he light band between 

h more so than thenormal 

fades aways, often the 





HERING'S THEORY OF COLOR VISION. 527 


still seen as a bright band on a uniform grayish field. 
Here there is no contrast to produce the error of judgment, 
and from this and other experiments Hering concludes that 
light acting on one part of the retina produces inverse 
changes in all the rest, and that this has an important part 
in producing the phenomena of contrasts, Similar pheno- 
mena may be observed with colored objects; in their nega- 
tive after-images each tint is represented by its complemen- 
tary, as black is by white in colorless vision. 

Endeavoring to exclude such loose general explanations 
as ‘errors of judgment,” Hering proposes a theory of vision 
which can only be briefly sketched here. We may pnt all 
our colorless sensations in a continuous series, passing 
through grays from the deepest black to the brightest 
white; somewhere half-way between will be a neutral 
gray which is as black as it is white. We may do some- 
thing similar with our color sensations; as in gray we see 
black and white so in purple we see red and blue, and all 
colors containing red and blue may be put in a series of 
which one end is pure red, the other pure blue. Sowith red 
and yellow, blue and green, yellow and green. If wecall to 
mind the whole solar spectrum from yellow to blue, through 
the yellow-greens, green, and blue-greens, we get a series in 
which all but the terminals have this in common that they 
conta some green. Green itself forms, however, a special 
point; it differs from all tints on one side of it in contain- 
ing no yellow, and from all on the other in containing no 
blue, In ordinary language this is recognized: we give 
it a definite name of ita own and call it green. Tts sim- 
pheity compared with the doubleness of its immediate 
neighbors entitles it to a distinct place in the color-sensa- 
tion series. There are three other color sensations which 
like green are simple and must have specific names of their 
own; they are red, blue, and yellow. Green may be pure 
green or yellow green or blue green, but never yellow 
and bluish at once, or reddish. Red may be pure or 
yellowish or bluish, but never greenish. Red and green 
are thus mutually exclusive; yellow and blue stand in a 
similar relationship. All other color sensations, as orange 





THE HUMAN BODY. 


suggest two of the above, and may be described as mixtures 
of them; but they themselves stand out as fundamental color 
sensations. Morcoyer, it follows from the above, that more 
than two simple colored sensations are never combined in 
a compound color sensation. 

Since red always excludes green, and yellow blue, we may 
call them anti-colors (the complementary colors of Young's 
theory), and are led to suspect that in the visual organ there 
must occur, in the production of each, processes which 
prevent the simultaneous production of the other, since 
there is no @ priori reason in the nature of things why 
we should not see red and green simultanconsly, as well as 
red and yellow. Along with our color sensations there is 
always some colorless from the black-white series; which 
we recognize in speaking of lighter and darker shades of 
the same color. 

Hering assumes, then, in the retina or some part of the 
nervous visual apparatus, three substances answering to the 
black-white, red-green, and yellow-blue sensational series, 
the construction of cach substance being attended with 
one sensation of its pair, and its destraction with the other. 
Thus, when construction of the black-white substance ex- 
ceeds destruction, we get a blackish-gray eensation; when 
the processes are equal the neutral gray; when destraction 
exceeds construction a light-gray, and so on, In the 
other color series similar things would occur; when con- 
struction of red-green substance exceeded destruction 
im any point of the retina we would get, say, a red feeling; 
if hen excess of destruction would give green sensa- 
tion. The intensity of any given simple sensation would 

‘io of the difference between the construc- 
corresponding substance, to the 

and destrnetions of visual sub- 

art of the visual apparatus, A 


When the construction 





UVERINGS THEORY OF COLOK VISION. 520 


and destruction of the red-green substance are equal no 
color sensation is aroused by it; and we get gray, due to 
those simultaneously occurring changes in the black-white 
substance which are always present, but were previously 
more or less cloaked by the results of the changes in 
the red-green substance. Red and green in certain pro- 
portions cause then a white or gray sensation, not because 
they supplement one another, as on Young's theory, but 
because they mutually cancel; and so for other comple- 
mentary colors. 

Moreover, according to Hering, destruction of a visual 
substance going on in one region of the retina promotes 
construction and accumulation of that substance elsewhere, 
but especially in the neighborhood of the exeited spot. 
Hence, when a white square on a black ground is looked 
at, destruction of the black-white substance overbalances 
construction in the place on which the image of the sqnare 
falls, but around this constraction oceurs in a high degree. 
When the eyes are shut, this latter retinal region, with its 
great accumulation of decomposable material, is highly 
irritable and, under the internal stimuli causing the idio- 
retinal light, breaks down comparatively fast, causing the 
corona, which may be intensely luminous; for with the 
closed eye the total constructive and destructive processes 
in the visual apparatus are small, and so the excess of do- 
struction in the coronal region bears a large ratio to the 
sum of the whole processes, The student must apply this 
theory for himself to the other phenomena of contrasts and 
negative images, as also to the gradual disappearance of 
differences between light and dark objects when looked at 
for a time with steady fixation; the general key being the 
principle that anything leading to the accumulation of a 
visual substance increases its decompositions under stimu- 
lation, and vice versa. The main value of Hering’s theory 
is that it utternpts to account physiologically for phenomena 
previously indefinitely explained psychologically by such 
terms us “errors of judgment,” which really leave the 
whole matter where it was, since if (as we must believe) 
mind is a function of brain, the errors of judgment have 





THE HUMAN BODY. 


still to be accounted for on physiological grounds, as due 
to conditions of the nervous system, 

Visual Perceptions. The sensations which light excites 
in us we interpret as indications of the existence, form, and 
position of external objects. The conceptions which we 
arrive at in this way are known a3 visnal perceptions. 
‘The full treatment of perceptions belongs to the domain of 
Psychology, but Physivlogy is concerned with the condi- 
tious under which they are produced. 

The Visual Perception of Distance. With one eye our 
perception of distance is very imperfect, as illustrated by 
the common trick of holding a ring suspended by a string 
@ short way in front of a porson’s face, and telling him 
to shut one eye und pass a rod through the ring. If apen- 
holder be held erect before one eye, while the other is 
closed, and an attempt be made to touch it with a finger 
moved across towards it, an error will nearly always 
be made. (Lf the finger be moved straight ont towards the 
pen it will be touched because with one eye we can estimate 
direction accurately and have only to go on moving the 
fingor in the proper direction till it meets the object.) In 
stich cases, however, we get some clue from the amount of 
effort needed to accommodate” the eye to see the object 
distinctly. When we use both eyes our perception of dis- 

h better; when we look at an object with two 
1 axes are converged on it, and the nearer 
or the convergence. We have a pretty 
d dge of the degree of muscular effort required _ 
tolerably near points. When 
abjeata ave ‘apparent sizo, and the modifi- 
cations th mages experience by aérial perspective, 
i 1 ve distance of objects is easiest 
yes; all stationary objects then 


when we 
nearest mi 





VISUAL PERCEPTION OF SIZE. 531 


we seem to see distance; it seems at first thought as definite 
a sensation as color. That it is not is shown by cases 
of persons born blind, who have had sight restored later in 
life by surgical operations. Such persons have at first no 
visual perceptions of distance: all objects seem spread out 
ona flat surface in contact with the eyes, and they only 
learn gradually to interpret their sensations so as to form 
judgments about distances, as the rest of us did uncon- 
sciously in childhood before we thought about such things, 

Tho Visual Porcoption of Sizo, The dimensions of the 
retinal image determine primarily the sensations on which 
conclusions as to its size are based; the larger the visual 
angle the larger the retinal image: since the visual angle 
depends on the distance of an object the correct perception 
of size depends largely upon a correct perception of distance; 
having formed a judgment, conscions or unconscious, a8 to 
that, we conclude as to size from the extent of the retinal 
region affected. Most people have been surprised now and 
then to find that what appeared a large bird in the clouds was 
only a small insect close to the eye; the large apparent size 
being due to the previous incorrect judgment as to the dis- 
tance of the object. The presence of an object of tolerably 
well-known height, a8 a man, also assists in forming con- 
ceptions (by comparison)as to size; artists for this purpose 
frequently introduce human figures to assist in giving an 
idea of the size of other objects represented. 

‘The Visual Perception of a Third Dimension of Space. 
‘This is very imperfect with one eye; still we can thus arrive 
at conclusions from the distribution of light and shade on 
an object, and from that amount of knowledge as to the 
relative distance of different points which is attainable 
monocularly; the different visual angles under which 
objects are seen also assist us in concluding that objects 
are farther and nearer; and so are not spread out onaplano 
before the eye, but occupy depth also. Painters depend 
mainly on devices of these kinds for representing solid 
bodies, and objects spread over the visual field in the third 
dimension of space. 

Single Vision with Two Eyos. When we look at a 





fiat object with both eyes we get a similar retinal 

each. Under ordinary circumstances we see, however, not 
two objects but one. SS eee 
move them so that the images of the object looked 
‘fall on the two yellow spots. ‘A point to the left of this 
forms its image on the inner (right) side of the left eye 
and the outer (right) side of the right, An object verti- 
Ca permbpinripr pene 
pce as spot of each eye; an object to the left 


tions of these corresponding points mean single objects, 

so interpret our sensations, This at least is the bis 
the experiential or empirical school of ps} 

others believe we have a sort of intuition on the ‘sul 
When the eyes do not work together, as in the muscular 
incodrdination of one stage of intoxication, then they are 
not turned so that images of the same objects fall on cor- 
responding retinal points, and the person sees double, 
When a squint comes on, as from paralysis of the external 
rectus of one eye, the sufferer at first sees double for the 
same reason. 

If a given object is looked at lines drawn from it throngh 
the nodal points reach the fovea centralis in each eye. 
Lines co drawn at the same time from a more distant object 
diverge less and meet each retina on the inner side of its 
fovea; but as above pointed ont the corresponding points 
for each retinal region on the inzide of the left eye, are on 
the outside of the right, and vice versa. Hence the more 

dc So, alzo, is a nearer object, be- 
g lines drawn from it through the 
» of the fovea in each eye. Most 
unobservant of this fact; we only 
e are looking at, and nearly 
0 fovew. That the fact is 
be readily observed. Hold 
n face and the other a little 
observe the other without moving 





STEREOSCOPIC VISION. 533 


the eyes; it will be seen double. For any given position of 
the eyes there is a surface in space, all objects on which 
produce images on corresponding points of the two retinas: 
this surface is called the Aoropter for that position of the 
eyes: all objects in it are seen single; all others in the visual 
field, double. 

Tho Perception of Solidity. When a solid object is 
looked at the two retinal images are different. If a tran- 
cated pyramid be held in front of one eye its image will be 
that represented at P, Fig. 142. If, however, it be held 
midway between the eyes, and looked at with both, then 
the left-eye image will be that in the middle of the 
figure, and the right-eye image that to the right, The 
small surface, dca, in one answers to the large surface, 
dc a,in the othér. This may be readily observed by 


ers font sere 
Ded Dal DEC 
VAS i a 


Pia, 


holding a small cube in front of the face and alternately 
looking at it with each eye. In such cases, then, the 
retinal images do not correspond, and yet we combine them 
80 a8 to see one solid object. This is known as stereoscopic 
vision, and the illusion of the common stereoscope depends 
on it. Two photographs are taken of the same object 
from two different points of view, one as it appears when 
seen by the left, and the other when looked at with the 
right eye. ‘These are then mounted for the stereoscope so 
that each is seen by its proper eye, and the scene or object 
is seen in distinct relief, as if, instead of flat pictures, 
solid objects were looked at, Of course in many stereo- 
scopic views the distribution of light and shade, etc., aasist, 
but these are quite unessential, us may be readily observed 
by enlarging the middle and right outline drawings of Pig. 





THE HUMAN BopY. 


142 to the ordinary size of a stereoscopic slide, and placing 
them in the instrument. A solid pyramid standing out 
into space will be distinctly perceived; if the be 
reversed the pyramid appears hollow. The pictures must 
not be too different, or their combination to give the idea 
of a single solid body will not take place. Many persons, 
indeed, fail entirely to get the illusion with ordinary stereo- 
seopic slides. The phenomena of stereoscopic vision mili- 
tate strongly against the view that there are any pre- 
arranged corresponding points in the two retinas. 

The Perception of Shine. When we look at a rippled 
lake in the moonlight, we get the perception of a *‘ shiny” 
or brilliant surface. The moonlight is reflected from the 
waves to the eyes in a number of bright points: these are 
not exactly the same for both eyes, since the lines of light- 
reflection from the surface of the water to each are 
different. The perception of brilliancy seems largely to 
depend on this slight non-agreement of the light and dark 
points on the two retinas. A rapid change of luminons 
points, to and fro between neighboring points on ono 
retina, seems also to produce it. 





CHAPTER XXXIV. 
THE EAR AND HEARING. 


The External Ear, The auditory organ in man con- 
sists of three portions, known respectively as the external 
ear, the middle ear or tympanum, and the internal ear or 
labyrinth; of these the latter is the essential one, contain- 
ing the end organs of the auditory nerve. The external 
ear consists of the expansion seen on the exterior of the 
head, called the concha, and a passage leading in from it, 


the external auditory meatus (D to ec, Fig. 143). This pas 


caternal auditory meatuns ec. mpante membrane; ‘B. the tenpasnis Wid 
the auditory ossicles in it; B to , Bustachian tube: -t, labyrinth, 

sage is closed at its inner end by the ¢ympanic or drum 
membrane. It is lined by a prolongation of the skin, 
through which numerous small glands, secreting the wax 
of the ear, open. 

The Tympanum, or drum-chamber of the ear (B, Fig. 
143), is an irregular cavity in the temporal bone, closed ex- 
ternally by the dram membrane. From its inner side the 
Eustachian tube (B to E) proceeds and opens into the 





536 THE HUMAN BODY, 


pharynx (g, Fig. 89)*, and the mucous membrane 0 - 
ity is continued up the tube to line the tym: 
this inside, and the skin of the external 
outside, is the proper tympanic membrane 
connective tissue. The inner wall of the 
bony except for two small apertures, the oval 
foramens, which lead into the labyrinth. D. life 
round aperture is closed by the lining mucous 
and the oval in another way, to be described 
The tympanic membrane, ¢ ¢, stretched like # 
across the onter side of the tympanum, forms a shallow 
funnel with its concavity outwards. \If a sheet of indian- 
rubber be stretched over a ring and pulled down in the 
centre, its form will be very like that of the membrane in 
question. It is pressed by the external air on its exterior, and 
by air entering the tympanic cavity through the Eustachian 
tube on its inner side. If the tympanum were closed these 
pressures would not be always equal when barometric pres- 
sure varied, and the membrane would be bulged in or out 
according as the external or internal pressure on it were 
the greater. On the other hand, were the Bustachian 
tube always open the sounds of our own voices would be 
extremely loud and disconcerting, so it is usually closed; 
but overy time we swallow it is opened, and thus the air- 
pressure in the cavity 1s kept equal to that in the external 
auditory meatus, By holding the nose, keeping the mouth 
shut, and forcibly expiring, air may be foreed under pres- 
sure into the tympanum, and will be held in part impris- 
oned there until the next act of swallowing. On making 
a balloon ascent or going rapidly down a deep mine, the 
sudden and great change of aérial pressure outside 
frequently causes painful tension of thedrum membnine, 
which may be gr alleviated by frequent swallowing, 

r i . Three small bones lie in the 


* Page 309. 





TYMPANIC BONES. 537 


an upper enlargement or head, which carries on its inner 
side an articular surface for the incus; below the head is a 
constriction, the neck, and below this two processes complete 
the bone; one, the Jong or slender process, is imbedded in a 
ligament which reaches from it to the front wall of the 
tympanum; the other process, the handle, reaches down 
between the mucons membrane lining the inside of the 
drum membrane and the 
membrane proper, and is 
firmly attached to the lat- 

ter near its centre and Mep 
keeps the membrane 
dragged in there so as to Mo 
give it its peculiar concare 

form, as seen from theout- 
side. The incus has a body 
and two processes and is 
much like a molar tooth 
with two fangs, On its 
body is an articular hollow 
to receive the head of the (Agnt OfFpean tron Se frost. 
mallens; its short process Be tabtione peck of itl tong 
(Jb) isattached by ligament Hang tng ree eo Uph oF 
tothe back wall of the tym- °rwoMars = 
panum; the long process (J?) is directed inwards to the 
stapes; on the tip of this process is a little knob, which 
represents a bone (08 orbiculare), distinct in early life. The 
stapes (S) is extremely like a stirrup, and its base (the foot- 
piece of the stirrup) fits into the oval foramen, to the mar- 
gin of which its edge is united by a fibrous membrane, 
allowing of a little play in and out. 

From the posterior side of the neck of the malleus « 
ligament passes to the back wall of the tympanum: this, 
with the ligament imbedding the slender process and fixed 
to the front wall of the tympanum, forms an antero-pos- 
terior axial ligament, on which the malleus can slightly 
rotate, so that the handle can be pushed in and the head 
out and vice versa. Ifa pin be driven through Fig. 144 
just below the neck of the mallens and perpendicular to the 


* 2 I 


Fra, 144-—Tho auditory ovlcles itm 


ul of 





THE HUMAN BODY. 


paper it will very fairly represent this axis of rotation. 
Connected with the malleus is a tiny muscle, called the 
tensor tympani; it is inserted in the handle of the bone below 
the axis of rotation, and when it contracts pulls the handle 
in and tightens the drum membrane. Another muscle 
(the sfapedius) is inserted into the outer end of the stapes, 
and when it contracts fixes the bone so as to limit its 
range of moment in and out of the fenestra ovalis, 

The Internal Ear. The labyrinth consists primarily of 
chambers and tubes hollowed out in the temporal bone and 
inclosed by it on al! sides, except for the oval and round 


anal; te, eon ii ama 


nt ort the org § may Hoot foe 
drew 


jor, and certain apertures on its inner 
sels and branches of the auditory 

1 these are closed water-tight in one 

in the bony labyrinth thus consti- 
rts, of the same general form but 

two aspace is left; thisis filled 

he perilymph; and the mem- 

i by a similar liquid, the endo- 








THE INTERNAL BAR, 539 


different aspects in Fig. 145, The vestibule is the central 
part and has on its exterior the oval foramen (Jv) into 
which the base of the stirrup-bone fits. Behind the vestibule 
are three bony semicircular canals, communicating with 
the back of the vestibule at each end, and dilated near one 
end to form an ampulla (vpa, vaa, and ha). The horizon- 
tal canal lies in the plane which its name implies and has 
its ampulla at the front end. The two other canals 
lie vertically, the anterior at right angles, and the pos- 
terior parallel, to the median antero-posterior vertical plane 
of the head. Their ampullary ends are turned forwards 
and open close together into the vestibule; their posterior 
ends unite (vc) and have a common vestibular opening. 

The bony cochlea is a tube coiled on itself somewhat 
like a snail’s shell, and lying in front of the vestibule. 

The Membranous Labyrinth. The membranous yesti- 
bule, lying in the bony, consists of two sacs communicating 
by a narrow aperture. 
The posterior is called 
the ufriculus, and into 
it the membranous 
semicircular canals 
open. The posterior, 
called the sacculus, 
communicates by a tube 
with the membranous 
cochlea. The mem- 
branous semicircular 
canals much resemble 
the bony, and each has Ai iiépA.metion through the cochles 
an ampulla; in most 
of their extent they are only united by a few irregular 
connective-tissue bands with the periosteum lining the 
bony canals; but in the ampulla one side of the mem- 
branons tube is closely adherent to its bony protector; at 
this point nerves enter the former. ‘The relations of the 
membranous to the bony cochlea are more complicated. A 
section through this part of the anditory apparatus (Fig. 
146) shows that its osseous portion consists of a tube 








wound two and # half times (from left to right | 

ear and vice versa) around.a central bony axis, the 

From the axis shelf, the lantina spiralis, projects 

tially subdivides the tube, extending farthest across in its 


triangular in cross-section and attacl 
the outer side of the bony cochlear 
lamina and the membranons cochlea 
cavity of the bony tube (Fig. 147) into 
the scala vestibuli, SV, and a lower, the 


Fra, 147,—Section of one collof the cochlea, 
mano of Reisner; CC, membranous coohl 


branous cochlea (CC), the latter being bounded above by 
the membrane of Reissner (7) and below by the basilar 
membrane (4). The inner edge of the lamina spiralis ‘is 
thickened and covered with connective tissue which is hol- 
lowed out so ag to form a spiral groove (the sulens spiralis, 
ss) along the whole length of the membranons cochlea. 
‘The latter does not extend to the tip of the bony cochlea; 
above its apex the scala yestibuli and seala tympani com- 
municate; both are filled with perilymph, and the former 

unicates below with the perilymph cavity of the ves- 
tibule, while the scala tympani abuts below on the round 
foramen, which, as has already been pointed ont, is closed 
by a membrane. The membranous cochlea contains cer- 





ORGAN OF CORTI. 


tain solid structares seated on the basilar membrane and 
forming the organ of Corti; the rest of its cavity is filled 
with endolymph, which communicates with that in the 
sacculus. 

‘The Organ of Corti. This contains the end organs of 
the cochlear nerves. Lining the suleus spiralis are cuboi- 
dal cells; on the inner edge of the basilar membrane they 
become columnar, and these are succeeded by a row which 
bear on their upper ends a set of short stiff hairs, and con- 
stitute the funer hair-cells, which are fixed below by a 
narrow apex to the basilar membrane; nerve-fibres enter 
them. To the inner hair-cells sncceed the rods of Corti 


wlohe rae a ana ae arte es 
the tunnel of Corti; #, inner, and ¢, outer roda; 4, basilar mombrase; r, reti- 
enlar membrane, 

(Co, Fig, 147), which are represented highly magnified in 
Fig. 148. These rods are stiff and arranged side by side in 
two rows, leaned against one another by their upper ends 
so as to cover in a tunnel; they are known respectively as 
the fener and outer rods, the former being nearer the 
lamina spiralis. Each rod has a somewhat dilated base, 
firmly fixed to the basilar membrane; an expanded head 
where it meets its fellow (the inner rod presenting there a 
concavity into which the rounded head of the outer fits); 
and 4 slender shaft uniting the two, slightly curved like an 
italic S. The inner rods are more slender and more 
numerous than the outer, their numbers being about 6000 
and 4500 respectively. Attached to the oxternal sides of 
the heads of the outer rods is the reficular membrane (r, 





THE HUMAN BODY. 


Vig. 148), which is stiff and perforated by holes. External 

to the outer rods come four rows of onfer hair-cells, con- 
nected like the inner row with nerve- 
fibres; their bristles project into the 
holes of the reticular membrane. Be- 
yond the outer hair-cells is ordinary 
columnar epitheliam, which passes 
gradually into cuboidal cells lining 
most of the membranous cochlea, 
Tho upper lip of the suleus spiralis 
is uncovered by epithelium, and is 
known as the limbus lamina spi- 
ralis; from it projects the fectortal 
membrane (t, Fig. 147) which extends 
over the rods of Corti and the hair- 
cells. 


Norvo-Endings in the Semicir- 
cular Canals and the Vestibule. 
Nerves reach the ampulla of each 


semicircular canal, and, perforating 
its wall, enter the epitheliam lining 
it which is there several Iayors thick 
(Fig. 149). Some of the cells (sp) 
are fusiform and have large nuclei; a 
slender external process runs from 
cach to the cavity of the ampulla and 
is then continued as slender stiff hair 
um (4), which projects into the endo- 
lymph. The deeper ends of these 
cella have been deseribed as joining 
the terminal branches of nervo- 
ibres, 8o that they must be regarded 
icle and saccule are somewhat 
collected among the hairs are 

, the car-stones or Otoliths, 


i Timbre of Sounds. Sounds, 
ups—notes and noises, Physi- 





PROPERTIES OF SOUND. 645 


cally, sounds consist of vibrations, and these, under most 
circumstances, when they first reach our auditory organs, 
are alternating rarefactions and condensations of the air, 
or aérial waves. When the waves follow one another uni- 
formly, or periodically, the resulting sensation (if any) is 
a note; when the vibrations are aperiodic it is a noise. 
In notes we recoguize (1) loudness or intensity; (2) pitch; 
(3) quality or ¢imbre, or, as it has been called, tone color; 
a note of @ given loudness and pitch prodaced by a trum- 
pet and by a violin has a different character or individu- 
ality in each case; this quality is its timdre. Before un- 
derstanding the working of the auditory mechanism we 
muat get some idea of the physical qualities in objective 
sound which the subjective differences of auditory sensa- 
tions are signs of, 

‘The loudness of a sound depends on the force of the 
aérial waves; the greater the intensity of the alternating 
condensations and rarefactions of these in the external 
auditory meatus, the louder the sound. The pitch of a 
note depends on the length of the waves, that is the dis- 
tance from one point of greatest condensation to the next, 
or (what amounts to the same thing) on the number of 
waves reaching the ear in given time, say asecond. The 
shorter the waves the more rapidly they follow one another, 
and the higher the pitch of the note. When audible 
vibrations bear the ratio 1; 2 to one another, we hear the 
musical interval called an octave. The note con the un- 
accented octave is due to 132 vibrations ina second. The 
note ¢’, the next higher octave of this, is produced by 264 
vibrations in a second: the next lower octave (great octave, 
©), by 66; and so on. Sound vibrations may be too rapid 
or too slow in succession to produce sonorous sensations, 
just as the ultra-violet and ultra-red rays of the solar 
spectrum fail to excite the retina. The highest-pitched 
audible note answers to about $8,016 vibrations in a 
second, but it differs in individuals; many persons cannot 
hear the cry of a bat nor the chirp of a cricket, which lie 
near this upper audible limit, On the other hand, sounds of 





ott THE HUMAN BODY. 


vibrational rate about 40 per second are not well heard, 
and a little below this become inaudible. The highest 
note used in orchestras is the d° of the fifth accented 
octave, produced by the piccolo flute, due to 4752 vibra- 
tions in a second; and the lowest-pitched is the #, of the 
contra octave, produced by the double bass. Modern grand 
pianos and organs go down to C, in the contra octave (33 
vibrations per second) or even A,, (274), but the musical 
quality of such notes is imperfect; they produce rather a 
“buzz” than a true tone sensation, and are only used 
along with notes of higher octaves to which they give a 
character of greater depth, 

Pendular Vibrations. Since the loudness of a tone de- 
pends on the vibrational amplitude of its physical antece- 
dent, and its pitch on the yibrational rate, we have still 
to seek the cauze of ¢fimbre; the quality by which we recog- 
nize the human yoice, the violin, the piano, and the flute, 
even when all sound the same note and of the same 
loudness, The only quality of periodic vibrations left to 
account for this, is what we may call wave-form. Think of 
the movement of a pendulum; starting slowly from its 
highest point, it sweeps faster and faster to its lowest, and 
then slower and slower to its highest point on the opposite 
side; and then repeats the movements in the reverse direc- 
tion. Graphically we may represent such vibrations by the 
outer continuous curved line in Fig. 150. Suppose the 
lower end of the pendulum to bear a writing point which 
marked on a sheet of paper traveling down uniformly 
behind it, and at such a rate a3 to travel the distance 0-1 
i ¢ If the pendulum were at rest the straight 

T ld be drawn. But if the pendulum were 
uld get a curved line, compounded of the 

t of the paper and the to-and-fro moye- 
m, Writing sometimes on one side 

nd sometimes on the other. Starting 

e pendulum crosses the middle, 0, we 

the curve 0 a" a’, ut first separating fast 

n slower, then returning, at first 





PENDULAR VIBRATIONS. a5 


gradually then faster, until it met the vertical again, at the 
end of 1’ and commenced an exactly similar excursion on its 
other side, at the end of which it would be back at 1, 
and in just the same position, and ready to repeat exactly 
the swing, with which we commenced. A pendulum 
thns executes similar movements in equal 
periods of time, or its vibrations are 
periodic. A full swing on each side of 
the position of rest constitutes a complete 
vibration, so the vibrational period of a 
second’s pendulum is two seconds: at the 
end of that time it is precisely where it 
was two seconds before, and moving in 
the same direction and at the same rate, 
It is clear that by examining such a curve 
we could tell exactly how the pendulum 
moved, and also in what period if we knew 
the rate at which the paper on which its 
point wrote was moving. The vertical 
line 0-1-2 is called the adscissa; per- 
pendiculars drawn from it and meeting 
the curve are ordinates: equal lengths on 
the ubsciasa represent equal times; where 
an ordinate from a given point of the 
abscissa meets the curve, there the writing 
point was at that moment; where succes- 
sive ordinates increase or decrease rapidly 
the pendulam moved fast from or towards 
its position of rest, and vice verse. Simi- 
larly, any other periodic movement may be 
perfectly represented by curves: and since 
the form of the curve tells us all about the 
movement, itisoommon tospeakof the “form ofavibration,” 
meaning the form of the curve which indicates its charac- 
ters, Periodic vibrations like those in Fig. 150, where the 
ordinates at first grow fast, then more slowly, then dimin- 
ish slowly and then faster, and represented by a symme- 
trical curve on one side the abscissa, which is repeated 





THE HUMAN BODY, 


exactly on the other side of the abscissa, are known as 
pendalar vibrations. 

‘Tho Composition of Vibrations. The vibrations of a 
second’s pendulum eet the air-particles in contact with it 
in similar movement, but the aérial wayes succeed one 
another too slowly to produce in ms the sensation of a 
musical note. If for the pendulum we substitute a tuning- 
fork (the prongs of which move in a like way), and the 
fork vibrates 132 times per 1’, then 132 aérial waves will fall 
on the tympanic membrane in that time, and we will bear 
the note ¢ of the unaccented octave. If the larger con- 
tinuous curve in Fig. 150 represent the aérial vibrations in 
this case, the distance 0 to 1 on the abscissa will represent 
rhy of a second. Let, simultanconsly, the air be set in 
movement bya fork of the next higher octave, c’, making 
264 vibrations per 1”; under the influence of this second fork 
alone, the aérial particles would move as represented by the 
smaller continuous curved line, the wayes being half as long 
and cutting the abscissa twice as often. But when both 
forks act together the atrial movement will be the algebraic 
sum of the movements duc to each fork; when both drive the 
air one way they will reinforce one another, and vice versa; 
the result will be the movement represented by the dotted 
line, which is still periodic, repeating itself at equal intervals 
of time, but no longer pendular, since it is not alike on the 
ascending and descending limbs of the curves, We thus 
get at the fact that non-pendular vibrations may be pro- 
duced by the fu of pendular, or, in technical phrase, by 


Each produces its own 

whose movernents, being the 
ue to all, must at any given in- 
ce car can pick out at will and 


can select that fraction of it which 

*. The air in the external 

- y given moment can only be in 

one state of rar ndensution and at one rate 





ANALYSIS OF VIBRATIONS. 547 


and in one direction of movement, this being the resultant 
of all the forces acting upon it; all clashing, and some push- 
ing one way and others another. If the resultant move- 
ment be not periodic it will be recognized as due to noises 
or to several simultaneous inharmonic musical tones; this 
is commonly the case when musical tones are not united 
designedly, and the ear thus get one criterion for distin- 
guishing movements of the air due to several simultaneous 
musical tones. However, a composite set of tones will give 
rise to periodic vibrations when all are due to vibrations of 
rates which are multiples of the same whole number. In 
such cases the movement of the air in the auditory meatus 
has no property except vibrational form by which the ear 
could distinguish it from a simple tone; when the two 
tuning-forks giving the forms of vibration (with rates as 
1 to 2), represented in Fig. 150 by continuous lines, are 
sounded together, we get the new form of vibration repre- 
sented by the dotted line, and this has the same period ag 
that of the lower-pitched fork; yet the ear can cloarly dis- 
tinguish the resultant sound from that of this fork alone, 
asa note of the same pitch but of different timbre; and 
with practice can recognize exactly what simple vibrations 
go to make it up. 

The Analysis of Non-Pendular Vibrations. If a per- 
son with # trained ear listens attentively to any ordinary 
musical tone, such aa that of a piano, he hears, not only 
the note whose vibrational rate determines the pitch of the 
tone as a whole, but a whole series of higher notes, in 
harmony with the general or fundamental tone; this latter is 
the primary partial tone, and the others are secondary 
partial tones; nearly all tones used in music contain both, 
If the prime tone be due to 132 vibrations a second (e), 
its first upper partial isc’ (= 264 vibrations per second); 
the next is the fifth of this octave (7 = 396 = 132 x 3 
vibrations per 1’); the next is the second octave, ¢” (132 x 
4 = 528 vibrations per 1’); the next isthe major third of the 
o” (=132 X 5 = 660 vibrations per second = ¢’), and go on. 
The only form of vibration which gives no upper partial 
tones is the pendular; we may call notes due to euch vibra- 





548 THE HUMAN BODY, 


tions simple tones; and we, consequently, recognize’ sin music 
tones which aro simple (such as those of tuning-forks) and 
those which are compound; these latter are non-pendular 
in form. 

We find, then, that the form of aérial vibrations deter- 
mines in our sensations the occurrence or non-occurrence 
of upper partial tones. It also, as we have seen, deter- 
mines the quality or timbre of the tone, since vibrational 
amplitude and rate are otherwise accounted for in sensa- 
tion by loudness and pitch. 

Tt can be proved, by the employment of the higher 
mathematics, that every periodic non-pendular movement 
can be analyzed (as the dotted curve of Fig. 150 may be) 
into a given number of pendular vibrations, that is, every 
compound vibration into a set of simple ones; and that 
every periodic non-pendular vibration can be made by the 
combination of pendular. Moreover, any given compound 
vibration can be analyzed into but one set of simple ones; 
noother combination will produce it, Consequently a vibra- 
tional movement of the airin the external auditory passage, 
producing a compound musical tone sensation, can be ex- 
hibited always, but only in one way, as the sum of a num~ 
ber of simple vibrations, whose rates are multiples of that 
which determines the pitch of the tone. 

Now when the trained ear listens to a tone with the 
object of detecting upper partials if present, it hears them 
only when the vibrations are non-pendular (i.¢, when 
theoretically they ought to be present), and those it hears 
are exactly those demanded by theory. By the help of 

in instruments their detection is made easy even to 
But in ordinary circumstances we do 

ial tones; we hear a note of the 

partial and of a certain timbro; and 

‘ials present are different, or of 

es, the timbre of the note varies. 

le that, just as the ear can at will 

an orchestra, analyzing the aérial 

¢ 0 t and follow the fraction of the 
whole due to that one, so it can and does analyze compound 





SYMPATHETIO RESONANCE. 549 


tones when proceeding from one instrament, and that the 
upper partials, not rising into consciousness as definite 
tones but present as subdued sensations, give its char- 
acter to the whole tone and determine its timbre. Tt 
might be, however, that the composition of non-pendular 
vibrations from pendular was a mere mathematical fiction, 
having no real existence in nature; before we can accept 
the above explanation of timbre, we must see if there is 
any evidence that, as a matter of fact, non-pendular vibra- 
tions, not only may be, but are made up by the combination 
of pendular. 

Sympathetic Resonance, Imagine slight taps to be 
given toa pendulum; if these be repeated at such intervals 
of time as to always help the ewing and never to retard it, 
the pendulum will soon be sct in powerful movement. If 
the tape are irregular, or when regular come at euch intervals 
as sometimes to promote and sometimes retard the move- 
ment, no great swing will be produced; but if they always 
push the pendulum in the way it is going at that instant, 
they need not come every swing in order to set up a power- 
ful vibration; once in two, three, or four swings will do. 
Astretched string, such as that of a piano, is in so far likea 
given pendulum that it tends to vibrate at one rate and 
no other; if aérial waves hit it at exactly the right times 
they soon set it in sufficiently powerful vibrations to cause 
it to emit an audible note. By using such strings we 
might hope to detect the separate pendular vibrations in 
any non-pendular aérial periodic movement if such really 
existed; certain strings would pick out the pendular com- 
ponent agreeing in rate with their own vibrational period 
and be soon set in powerful movement; while those not 
vibrating in the same period as any of the pendular compo- 
vents, would remain practically at rest, like the pendulum 
getting taps which sometimes helped and sometimes impeded 
‘its swing. If the dampers of a piano be raised and a note 
be sung to it, it will be found that several strings are set in 
vibration, such vibrations being called sympathetic. The 
human voice emits compound tones which can be mathe- 
matically analyzed into simple vibrations, and if the piano 





sérings oot Sn. remnant 7} Oe ee 
found to be exactly those which answer to 

vibrations and to no others. We thus get experimental 
grounds for believing that compound tones are really made 
up of a number of simple vibrations, and get an additional 
justification for the supposition that in the ear each note is 
analyzed into its pendular components; and that the differ- 
ence of sensation which we call timbre is due to the effect of 
the secondary partial tones thus perceived. If so, the 
ear must have in it an apparatus adapted for sympathetic 
resonance, 

It may be asked why, if the car analyzes vibrations in 
this way, do we not commonly perceive it? How is it that 
what wo ordinarily hear is the fimdre of a given tone and not 
the separate upper partials which give it this character? The 
explanation is more psychological than physiological, and 
belongs to the same series as the reason why we do not 
ordinarily notice the blind spot in the eye, or the donble- 
ness of objects out of the horopter, or the duplicity of 
stereoscopic images. We only use our senses in daily life 
when they can tell us something that may be usefal to us, 
and we neglect so habitually all sensations which would be 
useless or confusing, that at last it needs special attention 
to observe them at all, The way in which tones are com- 
bined to give fimdre toa note is a matter of no importance 
in the daily use of them, and so we fail entirely to observe 
the components and note only the resultant, until we make 
a careful and scientific examination of our sensations. 

‘Tho Functions of the Tympanic Membrane. If « 
stretched membrane, such as a drum-head, be struck, itwill 
be thrown into periodic vibration and emit fora time a note 

itch, The smaller the membrane and the 


ceed at the vibrational rate of 
the membrane t - will be set in powerful aympathetie 





USES OF DRUM-MEMBRANE. 551 


vibration; if they do not push the membrane at the 
proper times, their effects will neutralize one another: hence 
such membranes respond well to only one note. The 
panic membrane, however, responds equally well to a large 
number of notes; at the least for those due to aérial vibra- 
tions of rates from 60 to 4000 per second, running over 
eight octaves and constituting those commonly used in 
music. Thig faculty depends on two things; (1) the mem- 
brane is comparatively loosely and not uniformly stretched; 
(2) it is loaded by the tympanic bones. 

‘The drum-membrane is (p. 536) in the form of a shallow 
funnel with its sides convex towards its cavity; in such a 
membrane the tension is not uniform but increases towards 
the centre, and it has accordingly no proper note of its own. 
Farther, whatever tendency such a membrane may have 
to vibrate rather at one rate than another, is almost com- 
pletely removed by **damping” it; #. ¢. placing in contact 
with it something comparatively heavy and which yet has 
to be moved when the membrane docs. This is effected 
by the tympanic bones, fixed to the dram-membrane by the 
handle of the malleus. Another advantage is gained by the 
damping; once a stretched membrane is set vibrating it 
continues so doing for some time; but if loaded its move- 
ments cease almost as soon as the moving impulses. The 
dampers of a piano are for this purpose; and violin- 
players have to ‘‘damp” with the fingers the strings they 
have used when they wish the note to cease. When the 
aérial waves coase the loaded dram-membrane comes to rest 
almost immediately, and is ready to respond to the next 
set of waves reaching it. 

Functions of the Auditory Ossicles. When the air in 
the external auditory meatus is condensed it pushes in the 
handle of the mallens, This bone then slightly rotates on 
the axial ligament (p. 537) and drags ont the incns and 
with it the base of the stapes; the reverse occurs when air in 
the auditory passage is rarefied. Atrial vibrations thus set 
the chain of bones swinging, and pull ont and push in the 
base of the stapes, which sets up waves in the perilymph of 
the labyrinth, and these are transmitted through the mem- 





552 THE HUMAN BODY. 


branous labyrinth to the endolymph. These liquids 
chiefly water, and practically incompressible, the end of the 
stapes could not work in and out at the oval foramen, were 
the labyrinth elsewhere completely surrounded by bone: 
but the membrane covering the round foramen bulges out 
when the base of the stapes is pushed in, and wice versa; 
and so allows of waves being set up in the labyrinthic 
liquids. These correspond in period and form to those in 
the auditory meatus; their amplitude is determined by the 
extent of the vibrations of the dram-membrane. 

The form of the tympanic membrane causes it to trans- 
mit to its centre, where the malleus is attached, vibrations 
of its lateral parts in diminished amplitude but increased 
power; so that the tympanic bones are pushed only a little 
way but with considerable force. Its area, too, is about 
twenty times as great as that of the oval foramen, so that 
force collected on the larger area is, by pushing the tym- 
panic bones, all concentrated on the smaller, The ossicles 
also form a bent lever (Fig. 144) of which the fulcrum is at 
the axial ligament and the effective outer arm of this lever 
is about half as long again as the inner, and so the moye- 
ments transmitted by the dram-membrane to the handle of 
the malleus are communicated with diminished range, but 
i ower, to the base of the stapes. 

sound-wayes reach the labyrinth in this way 
npanum, but they may also be transmitted 
bones of the head in general; if the handle of 
ning-fork be placed on the vortex, for exam- 
ample. h sounds seem to have their origin in the head 
iteelf. 2} » When a vibrating body ie held between 
the teeth, 8 the end organs of the auditory 
v -bones; and persons who are deaf 
ry of the tympanum can thus be made 
hone. Of course if deafness be 
« nervous auditory apparatus no 
\ hear. 
Vo have already seen reagon 
is an apparatns adapted for 
yhich we recognize different 





FUNCTIONS OF COCHLEA. 553 


musical tone-colors; the minute structure of the membra- 
nous cochlea is such as to lead us to look for it there. An 
old view was that the rods of Corti, which vary in length, 
were like so many piano-strings, each tending to vibrate at 
a given rate and picking out and responding to pendular 
aérial vibrations of its own period, and exciting a nerve 
which gave rise to a particular tone sensation. When the 
labyrinthic fluids were set in non-pendular vibrations, the 
rods of Corti were thought to analyze these into their pendu- 
lar components, all rods of the vibrational rate of these be- 
ing set in sympathetic movement, but that rod most whose 
period was that of the primary partial tone; this would 
determine the pitch of the note, and the less-marked sen- 
sations due to the others affected would give it its timbre. 
The rods, however, do not differ in size sufficiently to 
account for the range of notes which we hear, and they are 
absent in birds, which undoubtedly distingnish different 
musical notes; and the nerve-fibres of the cochlea are not 
connected with them but with the hair-cella. 

On the whole it seems probable that the basilar mem- 
brane is to be looked upon as the primary arrangement for 
sympathetic resonance in theear. It increases in breadth 
twelve times from the base of the cochlea to its tip (the 
Jess width of the lamina spiralis at the apex more than 
compensating for the less size of the bony tube there) 
and is stretched tight across, but loosely in the other direc- 
tion. A membrane soatretched behaves as a set of separate 
strings placed side by side, somewhat as those of a harp 
but much closer together; and each string would vibrate at 
its own period without influencing much those on each side 
of it. Probably, then, each transverse band vibrates tosim- 
ple tones of its own period, and excites the hair-cella which 
lie on it, and through them the nerve-fibres. Perhaps the 
rods of Corti, being stiff, and carrying the reticular mem- 
brane, rab that against the upper ends of the hair-colls which 
project into its apertures and so help in a subsidiary way, 
each pair of rods being especially moved when the band of 
basilar membrane carrying it is set in vibration. The tee- 
torial membrane is probably a “damper; it is soft and 





Semicircular Canals. 
Many noises are merely spoiled music; stra due to tones 
s0 combined as not to give rise to periodic vibrations; these 
are probably heard by the cochlea. It & single violent 
air-wave ever cause a sound sensation (which is doubtful 
since any violent push of an elastic substance, such as the 
air, will cause it to make several rebounds before coming to 
rest) we perhaps hear it by the vestibule; the otoliths, there 
in contact with the auditory hairs, are imbedded in a 
tenacious gummy mass quite distinct from the proper 
endolymph, and are not adapted for executing regular 
vibrations, but they might yield to asingle powerful impulse 
and transmit it to the hair-cells, and through them 
stimulate the nerves. There is reason to believe that the! 
semicircular canals have nothing to do with hearing; their 
supposed function is described in Chapter XXXV. 

Auditory Perceptions. Sounds, as a general rule, do 
not seem to us to originate within the auditory apparatus; 
werefer them to an external source, and toa certain extent 
can judge the distance and direction of this, As already 
mentioned, the extrinsic reference of sounds which reach the 
labyrinth through the general skull-bones instead of through 
the tympanic chain is imperfect or absent. The recogni- 
tion of the distance of asounding body is possible only when 
the sound is well known, and then not very accurately; from 
its faintness or loudness we may make in some cases a 
pretty good guess, Judgments as to the direction of a 
sound are also liable to be grossly wrong, a& most persons 
¢ I ver, when a sound is heard louder 

t ht ear we can recognize that its 

left; when eq mally with both ears, that it is 

r behi 


behind the ear, since it collects, 
into the external auditory 
rom the front, By turning 
ying changes of sensation 





AUDITORY PERCEPTIONS. 555 


in each earwe can localize sounds better than if the head be 
kept motionless. The large movable concha of many ani- 
mals, as a rabbit or a horse, which can be turned in several 
directions, is probably an important aid to them in de- 
tecting the position of the source of a sound. That the 
recognition of the direction of sounds is not a true sensation, 
but a judgment, founded on experience, is illustrated by the 
fact that we can estimate much more accurately the direc- 
tion of the human voice, which we hear and heed most, 
than that of any other sound. 





CHAPTER XXXIV. 


TOUCH, THE TEMPERATURE SENSE, THE 
MUSCULAR SENSE, COMMON SENSA- 
TION, SMELL, AND TASTE. 


Nerve-Endings in the Skin. Many of the afferent 
skin-nerves end in connection with hair-bulbs; the fine 
hairs over most of the cutaneous surface, projecting from 
the skin, transmit any movement impressed on them, with 

increased force, to the nerve- 
fibres ut their fixed ends, In 
many animals, as cats, large, 
specially tactile, hains are de- 
veloped on the face, and 
these have a very rich nerve- 
supply. Fine branches of 
axis cylinders have also been 
described as penetrating be- 
tween epidermic cells and 
ending there without termi- 
nal organs. In or immedi- 
ately beneath the skin several 
peculiar forms of nerve end 
organs have also been de- 
scribed; they are known as 
(1) Tonch-cells; (2) Pacinian 
corpuscles; (3) Tactile cor- 
puscles; (4) End-bulbs. — * 





NERVE END ORGANS IN SKIN. 557 


They are oval, from 1.5 to 2.5 mm. (5 to jy inch) long, 
by about half that width, and have a whitish translucent 
appearance, with a more opaque centre. When magnified 
each is found to consist of a core, surrounded by many 
concentric capsules, 4. A nerve-fibre, a, enters at one end, 
and its axis cylinder, ¢, rans along the core to the other, 
where it terminates in one or two little knobs, or a number 
of fine branches. 

The tactile corpuscles lie in papille of the dermis, and 
are oval and about .08 mm. (y}q inch) in length. They 
contain a soft core, enveloped by a connective-tissue cap- 


yi 


Fro, 132. —Dormic pa ith tnetile ae, Aw 
nerve-fibres; 
ac 
}, tactile corpuselo; ¢, entering nerve. 
Bile. 0, ‘@ papilla, containing ‘ski aot ‘ea in 


sule, and separated into several masses. Two, three, or 
more nerve-fibres go to each corpnscle and appear to end 
in plates lying between each of the segments of the core. 
Tactile corpuscles are numerous in the skin of the hand 
and foot, but are rare elsewhere, This limited distribution 
over the surface militated against the belief that they were 
tactile end organs; but it has lately been found that simpler 
bodies, the fouch-cvlls, of the same essential structure but 
receiving only one nerve-fibre each, are distributed all over 
the skin; the more complex, and probably more irritable, 
form being found where the epidermis is especially thick, 





get several kinds of sensation; touch proper, heat and cold, 
and pain; and we can with more or less accuracy localize 
them on the surface of the Body. The interior of 
mouth possesses also these sensibilities. ‘Through 
proper we recognize pressure or traction exerted on 
skin, and the force of the pressure; the softness or 
ness, roughness or smoothness, of the body 
and the form of this, when not too large te be felt all over, 
In the latter case, as when we move the hand over an 
object to study its shape, muscular sensations are com- 
bined with proper tactile, and such a combination of the 
two sensations is frequent; moreover, we rarely touch any- 
thing without at the samo time getting temperature sen- 
sations; so that pure tactile feelings are rare. From an 
evolution point of view, touch is probably the first 
differentiated sensation, and this primary position it 
largely holds in our mental life; we mainly think of the 
things about us as objects which would give us certain tac- 
tile sensations if we were in contact with them, Thongh 
the eye tells us much quicker, and at a greater range, what 
are the shapes of objects and whether they are smooth, 
igh, and so on, our real conceptions of round and square 


y the teachings of the eye into mental 
nse, A person who saw but had no 


solid objects very differently 


tactile sense varies on different parts 
of the t is greatest on the forehead, temples, and 





back of the forearm, where a weight of 2 milligr. (.03 
grain) pressing on an area of 9 sq. millim. (.0139 sq. inch) 
can be felt. On the front of the forearm 3 milligr. (.036 
grain) can be similarly felt, and on the front of the fore- 
finger 5 to 15 milligr, (,07-0.23 grain). 

In order that the sense of touch may be excited neigh- 
boring skin areas must be differently pressed; when we lay 
the hand on a table this is secured by the inequalities of 
the skin, which prevent end organs, lying near together, 
from being equally compressed. When, however, the hand 
is immersed in a liquid, as meroury, which fits into all its 
inequalities and presses with practically the same weight 
on all neighboring immersed areas, the sense of pressure is 
only felt at a line along the surface, where the immersed 
and non-immersed parts of the skin meet. 

It was in connection with the tactile sense that the facts 
on which so-called psycho-physical law (p. 473) is based, 
were first observed. The smallest perceptible difference of 
pressure recognizable when touch alone is used, is about 
4: fe. we can just tell a weight of 20 grams (310 grains) 
from one of 30 (465 grains) or of 40 grams (620 grains) 
from one of 60 (930 grains); the change which can just be 
recognized being thus the samedraction of that already act- 
ing as a stimulus, The ratio only holds good, however, 
for a certain mean range of pressures; and its existence for 
any has lately been denied. ‘The experimental difficulties in 
determining the question are considerable; muscular sensa- 
tions must be rigidly excluded; the time elapsing between 
laying the different weights on the skin must always be 
equal; the samo region and area of the skin must be used; 
the weights must have the same temperature; and fatigue of 
the organs must be eliminated. Considerable individual 
variations are also obsorved, the least perceptible difference 
not being the same in all persons. 

Tho Localizing Power of the Skin. When the eyes are 
closed and a point of the skin is touched we can with some 
aconracy indicate the region stimulated; although tactile 
feel ings. are in general characters alike, they differ in some- 
thing (local sign) besides intensity by which we can distin- 





blunted points of 4 pair of compasses) in ¢ 
may be felt ag two. ‘The following table Mustrates 


of the differences observed— . 


‘Tho localizing power isa little more acuté across the | 

axis of a limb than in it; and is better when the “ 

is only strong enongh to just cause a distinct tactile sensa- 
tion; than when it is moro power- 
ful; it is also yery readily and 
rapidly improvable by practice, 

It might be thought that this 
localizing power depended directly 
on nerve distribution; that each 
touch-nerve had connection with 
4 special brain-centre on the one 
hand (the excitation of which 
caused a sensation with a charac 
teristic local sign), and at the other 
ond was distributed oyer a certain 
skin area, and that the larger this 

k area the farther apart might two 
points be and still give rise to only one sensation. If thik 
wore 80, howevor, the peripheral tactile areas (each being 
determined by tho anatomical distribution of a nerve-fibre) 





LOCALIZATION OF TACTILE SENSATIONS, 561 


must have definite unchangeable limits, which experiment 
shows that they do not possess. Suppose the «mall areas in 
Fig. 153 to each represent a periphoral area of nerve distribu- 
tion. If any two points in c were touched we would accord~ 
ing to the theory get butasingle sensation; but if, while 
the compass points remained the same distance apart, or were 
evenapproximated, one were placed in ¢ and the other ona 
contiguous area, two fibres would be stimulated and we ought 
to get two sensations; bnt snch is not the case; on the same 
skin region the points must be always the same distance 
apart, no matter how they be shifted, in order to give rise 
lo two just distinguishable scusutions, 

It is probable that the nerve areas are much smaller than 
the tactile; and that several unstimulated must intervene 
between the excited, in order to produce sensations which 
shall be distinct. If we suppose twelve unexcited nerve 
areas must intervene, then, in Fig. 153, a and 4 will be just 
on the limits of a single tactile area; and no matter how 
the points are moved, so long as eleven, or fewer, unexcited 
areas come between, we would get a single tactile sensation; 
in this way we can explain the fact that tactile areas have 
no fixed boundarics in the skin, although the nerve distri- 
bution in any part must be constant. We also eee why the 
back of a knife laid on the surface causes a continuous 
linear sensation, although it touches many distinct nerve 
areas; if we could discriminate the excitations of each of 
these from that of its immediate neighbors we would get 
the sensation of # series of points touching us, one for cach 
nerve region excited; but in the absence of intervening 
unexcited nerve areas the sensations are fused together, 

‘The ultimate differentiation of tactile areas takes place in 
the central organs, as will be more fally pointed ont in the 
next chapter. Afferent nerve impulses reaching the spinal 
cord from a finger-tip enter the gray matter and tend 
to radiate some way in it; from the gray region through 
which they spread, impulses are sent on to perceptive 
tactile centres in the brain; if two skin-pointa are so close 
that their regions of irradiation in the cord overlap, then 
the two points touched cannot be discriminated in con- 





does it tend to keep its own proper ‘gray 
matter of the cord, and get on to its own proper brain- 
centre alone, hence the increase of tactile diserimination 
with practice, for we cannot suppose it to be due to a growth 
of more nerve-fibres down to batpaclcristice ay 
of the old, with smaller areas of anatomical distribution. 
Asa general rule, more movable parts have smaller tactile 
areas; this probably depends on practice, since they are the 
parts which get the greatest number of different tactile 
stimulations. 

‘The Temperature Sense. By this we mean our faculty 
of perceiving cold and warmth; and, with the help of these 
sensations, of perceiving temperature differences in external 
objects. Its organ is the whole skin, the mucous membrane 
of mouth and fauces, pharynx and gullet, and the entry of 
thenares. Direct heating or cooling of a sensory nerve may 
stimulate it and cause pain, but not a true tem) 
sensation; and the degree of heat and cold requisite is much 
greater than that necessary when a temperature- 
surface is acted upon; hence we must assume the presence 
of temperature end organs. 

In a comfortable room we feel at no part of the Body 
either heat or cold, although different parts of its surface 
are at different temperatures; the fingers and nose being 
cooler than the trunk which is covered by clothes, and this, 
in turn, cooler than the interior of the mouth. The tem- 
perature which » given region of the bei 
has (az measured by a thermometer) when it fecls neil 
heat x ts femperature-sensation 2670, and is not 


ef h and vice versa; the sensation is 
more marked the greater the difference, and the more 





TEMPERATURE SENSATIONS. 563 


suddenly it is produced; touching a metallic body, which 
conducts heat rapidly to or from the skin, causes a more 
marked hot or cold sensation than touching a worse con- 
ductor, as a piece of wood, at the same temperature. 

‘The change of temperature in the organ may be brought 
about by changes in the circulatory apparatus (more blood 
flowing through the skin warms it and less leads to its cool- 
ing), or by temperature changes in gases, liquids, or solids in 
contact with it. Sometimes we fail to distinguish clearly 
whether the canse is external or internal; a person coming 
in from a windy walk often feels » room uncomfortably warm 
which is not really so; the exercise has accelerated his circula- 
tion and tended to warm his skin, but the moving outer air 
has rapidly conducted off the extra heat; on entering the 
honse the stationary air there does this less quickly, the 
skin gets hot, and the cause is supposed to be oppressive 
heat of the room. Hence, frequently, opening of win- 
dows and sitting in a draught, with its concomitant risks; 
whereas keeping quiet for five or ten minutes, until the 
circulation had returned to its normal rate, would attain 
the same end without danger. 

The acuteness of the temperature sense is greatest at 
temperatures within a few degrees of 30°C. (86° F.); at 
these differences of less than .1° ©. can be discriminated, 
Asa means of measuring absolute temperatures, however, 
the skin is very unreliable, on account of the changeability 
of its sensation zero, We can localize temperature sensa- 
tions much as tactile, but not so accurately. 

Aro Touch and Tomperature Sensations of Different 
Modality? ‘Tactile and temperature feelings are ordina- 
rily so very different that we can no more compare them 
than luminous and auditory; and if we accept the modern 
modified form of the doctrine of specific nerve energies 
(p. 191), in accordance with which the same sensory fibre 
when excited always aronses a sensation of the same quality 
because it excites the same brain-centre, it is hard to con- 
ceive how the same fibre could at one time arouse a tactile, 
and at another a temperature sensation. It has, however, 
been maintained that touch and temperature feelings 








MUSCULAR FEELINGS, 


and, conversely, cases in which the patient could feel that 
he had been touched but was unable to say whether with a 
hot or cold object. 

The Muscular Sense. In connection with our muscles 
we have sensations of great importance, although they do 
not often become so obtrusive in consciousness as to arouse 
our attention until we look for them. Certain of these 
feelings (muscle sensations proper) are due to the excitation 
of sensory nerves ending within the muscles themselves: 
the others (innervation sensations) have probably a central 
origin and accompany the starting of volitional impulses 
from brain-cells; they are only felt in connection with the 
voluntary skeletal muscles. 

The proper muscle sensations only become marked on 
powerful or long-continued muscular effort (cramp, fatigue), 
but a lower grade of them, not distinctly perceived, proba- 
bly accompanies all muscular activity. 

The innervation feelings are of far more consequence. 
‘They accompany the slightest movement of a skeletal mus- 
cle, and wederive from them means of determining with 
great accuracy the force and extent of the contraction 
willed. The belief that their origin is central mainly rests 
on the fact that we have sensations, not merely of executed 
but of intended movements. The actual nature of the 
movement performed is probably characterized by other 
contemporary sensations, as of the muscle sense proper, 
from pressure and folding of the skin, and 80 on. 

The innervation feelings thus stand apart and opposed 
to all our Others as primary factors in our mental life; they 
represent the reactive work of the organism with respect 
to its environment. Some distinguished physiologists, 
however, deny their existence, ascribing them all to a 
peripheral origin, either in sensory muscle-neryes, or in 
skin-nerves affected when a part of the Body is moved. 
As, however, we can determine more accurately the differ- 
ence between two weights when we lift them than we can 
when they are merely laid on a hand supported by a table 
{see below), there are undoubtedly (apart from cramp and 
fatigue) true muscular sensations distinct from tactile; and 








COMMON SENSATIONS. 567 


tibly different pressures have the ratio 1: 3, with the mus- 
cular sense differences of #, can be perceived. 

Common Sensations. Under this name are included the 
sensations which we do not mentally attribute to the prop- 
erties of external objects, but to conditions of our own 
Bodies; of them we may here consider pain, hunger, and 
thirst. 

Pain arises when powerful mechanical or thermal stimuli 
act on the skin, and when a sensory nerve-truank (except the 
optic, anditory, or olfactory) is directly excited. Most 
commonly we derive the feeling through cutaneous or sub- 
entaneous nerves, and hence it has been supposed that pain 
is not a sensation of distinct modality due to the excitation 
of special nerve-fibres, but is dependent on excessive excite- 
ment of ordinary tactile fibres; and pressure or temperature 
sensitions do undoubtedly gradate into painful as the 
stimuli increase. If this be s0, pain is a sort of incodrdi- 
nate or “convulsive” sensation. We shall see in Chapter 
XXXYV. that, when a sensory nerve is normilly excited in 
adecapitated animal, regular purpose-like reflex movements 
result: but if the stimulus be very powerful, ora nerve-= 
trank be directly excited, then inco-ordinate convulsions 
oceur: the afferent impulses radiate farther in the centre 
and produce a new and useless result. We may suppose 
something similar to oceur in the cutaneous nerves of an 
animal still possessing sensory brain-centres, if the stimuli 
acting on the skin are such as to excite the end organs very 
powerfully, or the sensory fibres directly without the inter- 
mediation of end organs; that a new sensation should be 
thus aroused, different from tactile though gradually shad- 
ing off into them, is a phenomenon comparable with the 
production of new color sensations by combinations of the 
fundamental ones, In such case, too, we could understand 
the difference of kinds of “pain” in a more general sense 
of the word; muscular cramp, dazzling, and disagreeably 
shrill or inharmouionsly combined tones, might all be 
looked upon as inco-ordinate sensations, each with a charac- 
acter of its own determined by the central apparatus ex- 
cited, 








SMELL. 


Hunger and Thirst. These sensations, which regulate 
the taking of food, are peripherally localized in conscions- 
ness, the former in the stomach and the latter in the throat, 
and local conditions no doubt play a part in their produc- 
tion; though general states of the Body are also concerned. 

Hunger in its first stages is probably due to a condition 
of the gastric mucous membrane which comes on when the 
stomuch has been empty some time, and may be temporarily 
stilled by filling the organ with indigestible substances. 
But soon the feeling comes back intensified and can only 
be allayed by the ingestion of nutritive substances; pro- 
vided these are absorbed and reach the blood, their mode of 
entry is unessential; the hanger may be stayod by injoc- 
tions of food into the rectum as well as by putting it into 
the stomach, 

Similarly, thirst may be temporarily relieved by moisten- 
ing the throat without swallowing, but then soon returns; 
while it may bo permanently rolieved by water injections 
into the veins, without wetting the throat at all. 

While both sensations thus depend in part on local 
peripheral conditions of afferent nerves (pneumogustric 
and glossopharyngeal), they may be also, and more power- 
fully, excited by poverty of the blood in foods and water; 
this probably directly stimulates the hunger and thirst 
brain-centres. 

Smell, The olfactory organ consists of the upper por- 
tions of the two nasal cavities, over which the endings of 
the olfactory nerves are spread and where the mucous 
membrane has a brownish-yellow color. This region 
(regio olfactoria) covers the upper and lower turbinate 
bones (0, p, Fig. 89*), which are expansions of the ethmoid 
(p. 75) on the outer wall of the nostril chamber, the oppo- 
site part of the partition between the nares, and the part of 
the roof of the nose (m, Fig. 89) separating it from the 
cranial cavity. The epithelium covering the mucous mem- 
brane contains two varieties of cells arranged in several 
layers (2, Fig. 154). Some cells are much like ordinary 
columnar epithelium but with Jong branched processes 
attached to their deeper ends; the others have a large 

*P, 900, 





570 THE HUMAN BODY. 


nucleus surrounded by « little protoplasm; a slender exter- 
nal process reaching to the surface; and a very fine deep one. 
‘The latter cells have been supposed to be the proper olfac- 
tory end organs, and to be connected with the fibres of the 
olfactory nerve, which enter the deeper strata of the epithe- 
lium and there divide; but it is doubtful whether both 
kinds of cells are not s0 connected. 

Odorous substances, the 
stimuli of the olfactory appa- 
ratus, are always gaseous and 
frequently act powerfully 
when present in very small 
amount. We cannot, how- 
ever, classify them by the sen- 
sations they arouse, or arrange 
them in series; and smells are 
bat minor sensory factors in 
our mental life. We commonly 
refer them to external objects 
since we find that the sensa- 
tion is intensified by * sniff- 
ing” air powerfully into the 
nose, and ceases when the 
nostrils are closed. Their 
peripheral localization is, how- 
ever, imperfect, for wo con- 
found many smells with tastes 
(see below); nor can we judge 
well of the direction of an 

» odorous body through the 
olfactory sensations which it 
arouses. 

o nerves of common sensation, 


un of taste is the mucous membrane on 

ue and possibly other patts of the 

the mouth cavity. The nerves concerned are 
tributed over the hind part of the 





TASTE. on 


tongue, and the lingual branches of the inferior maxillary 
division (p. 170) of the trigeminals on its anterior two 
thirds. 

On the tongue the nerves run to papille; the circumval- 
late (p. 313) have the richest supply, and on these are cer- 
tain peculiar end organs (Fig. 155) known as éasfe-buds, 
which are oval and imbedded in the epidermis covering the 
side of the papilla. Each consists, externally, of anumber 
of flat, fusiform, nucleated cells and, internally, of six or 
eight so-called (aste-cells. The latter are much like the 
olfactory cells of the nose, and are probably connected with 
nerve-fibres at their deeper ends. The capsule formed by 
the enveloping cells has a small opening on the surface; 


each taste-cell terminates in a very fine thread which pro- 
trades there, 'Taste-buds are also found on some of the 
fungiform papillw, and it is possible that simpler strnc- 
tures, not yet recognized, consisting of single taste-cella 
are widely spread on the tongue, since the sense of taste 
exists where no taste-buds can be found. ‘The filiform 
papille are probably tactile. 

In order that substances be tasted they must be in solu- 
tion: wipe the tongue dry and put a crystal of sugar on it; 
no taste will be felt until exuding moisture has dissolved 
some of the crystal. Tustes proper may be divided into 
aweet, bitter, acid, and saline, Tntellectually they are, like 
smells, of small valne; the perceptions we attain through 
them as to qualities of external objects being of little use, 





THE HUMAN BODY. 


except as aiding in the selection of food, and for that pur- 
pose they are not by any means safe guides at all times. 

Many so-called tastes (flavors) are really smells; odorif- 
crous particles of substances which are being eaten reach the 
olfactory region through the posterior nares and ‘arouse sen- 
sations which, since they weccompuny the presence of objects 
in the mouth, we take for tastes. Such is the case, ¢.g., 
with most spices; when the nasal chambers are blocked or 
inflamed by a cold in the head, or closed by compressing 
the nose, the so-called taste of spices is not perceived when 
they are eaten; all that is felt, when cinnamon, ¢g., is 
chewed under such circumstances is a certain pungency due 
to its stimulating nerves of common sensation in the tongue. 
This fact is sometimes taken advantage of in the practice 
of domestic medicine when # nauseous dose, as rhubarb, is 
to be given toachild. Tactile sensations play also a part 
in many so-called tastes. 

Most persons taste bitters best with the back of the 
tongue and sweets towards the tip; but this is not constant, 
‘The curious interference of tastes which takes place when 
the acidity of a sour body is covered by adding a sweet one, 
which does not in any way chemically neutralize the acid 
(when sugar is put on a lemon for example), needs explana- 
tion, 





CHAPTER XXXV, 


THE FUNCTIONS OF THE BRAIN AND 
SPINAL CORD. 


The Special Physiology of Nerve-Centres. We have 
already studied the general physiological properties of 
nerves and nerve-centres (Chap. XIII.) and found that 
while the former are mere tranamitters of nervous impulses, 
the latter do much more. In some cases the centres are aufo- 
matic; they originate nerve impulses, as illustrated by the 
beat of the heart under the influence of its ganglia, In 
other cases a feeble impulse reaching the centre gives rise 
to # great discharge of energy from it (as when an unex- 
pected noise produces a violent start, due to many impulses 
sent out from the excited centre to numerous muscles), 60 
that certain centres are irritadle; they contain a store of 
energy-liberating material which only needs a slight dis- 
turbance to upset its equilibrium and produce many efferent 
impulses as the result of one afferent. Farther, the im- 
pulses thus liberated are often co-ordinated. When mucus 
in the windpipe tickles the throat and excites afferent nerve 
impulses, these, reaching a centre, cause discharges along 
many ¢fferent fibres, so combined in sequence and power 
ag to produce, not a mere aimless spasm, bnt a cough 
which clears the passage. In still other cases the excita- 
tion of centres, with or without at the same time some of 
the above phenomena, is associated with sensations or other 
states of consciousness. We have now to study which of 
these powers are manifested by different parts of the cen- 
tral cerebro-spinal nervous system, and ander what cireum- 
stances and in what degree: what is known of the general 
functions of the sympathetic and sporadic ganglia has al- 
ready been stated (p. 183). 








REFLEX ACTIONS OF THE CORD. 575 


squat on its belly instead of assuming the more erect posi- 
tion of the uninjured animal; its respiratory movements 
cease (their centre being removed with the medulla); the 
hind legs at first remain sprawled out in any position into 
which they may happen to fall, but after a time are drawn up 
into their usual position, with the hip and knee joints flexed; 
having made this movement the animal, if protected from 
external stimuli, makes no other by its skeletal muscles; it 
has lost all spontaneity, and only stirs under the influence 
of immediate excitation. Nevertheless the heart goes on 
beating for hours; the muscles and nerves, when examined, 
are found to still have all their usual physiological proper- 
ties; and, by suitable irritation, the animal can be made to 
excente a great variety of complex movements, But it 
is no longer a creature with a will, doing things which we 
cannot predict; it is an instrument which ean be played 
upon, giving different responses to different stimuli (as dif- 
forent notes are produced when different keys of a piano are 
struck), and always the same reaction to the same stimulus; 
so that we can say beforehand what will happen when we 
touch it. Such actions are called reflex or excito-motor and 
fall into two groups; (1) orderly or purpose-like reflexes, 
which are correlated to the stimulus and are often defensive, 
tending, for instance, to remove an irritated part from the 
irritating object; (2) disorderly or convulsive reflexes, not 
tending to produce any definite result, and affecting either # 
limited region or all the muscles of the body. 

In higher animals similar phenomena may be observed. 
Tfarabbit’s spinal cord be divided at the bottom of the neck 
the animal is at first thrown into a flaccid limp condition 
like the frog, but it soon recovers. Voluntary movements 
in muscles supplied from the spinal cord behind the section 
are never seen again; but on pinching the hind foot it is 
forcibly withdrawn. Men, whose spinal cord has been 
divided by stabs or disease below the level of the fifth corvical 
spinal roots (above which the fibres of the phrenic nerve, 
which are necessary for breathing, pass ont), sometimes live 
for a time, bat can no longer move their legs by any 
effort of the will, nor do they feel touches, pinches, or hot 








DISORDERLY REFLEX MOVEMENTS, 577 


of the body to contract, and the animal isconyulsed. Hore 
then we see that a feeble stimulation causes a limited and 
purpose-like response; stronger causes a wider radiation of 
efferent impulses from the cord and the contraction of more 
muscles, but still the movements aré co-ordinated to an 
end; while abnormally powerful stimulation of the sensory 
nerves throws all the motor fibres arising from the cord into 
activity, and calls forth inco-ordinate spasmodic action. 
The orderly movements are very uniform for a given stimu- 
lation; if the anal region be pinched, both hind Iegs are 
raised to push away the forceps; if a tiny bit of bibulous 
paper moistened with dilute vinegar be put on the thigh, 
the lower part of that leg is raised to wipe it off; if on the 
middle of the back near the head, both feet are wiped over 
the spot: if on one flank, the leg and foot of that side are 
used, and so on; in fact, by careful working, the frog's skin 
can be mapped into many regions, the application of acidu- 
lated water to each causing one particular movement, 
(lue to the co-ordinated contractions of muscles in different 
combinations, and never, under ordinary circumstances, 
any bot that one movement. ‘The above purpose-like 
reflex movements may all be characterized as defensive, 
but all orderly reflexes are not so. For example, in the 
breeding season the male frog clasps the female for several 
days with his forelimbs. If a male at this season bo 
decapitated and left to recover from the shock, it will be 
found that gently rubbing his sternal region with the finger 
causes him to clasp it vigorously. 

Disorderly Reflexes or Roflex Convulsions. These 
come on when an afferent nerve-trunk is stimulated instead 
of the tactile end organs in the skin; or when the skin is 
very powerfully excited; or, with feeble stimuli, in certain 
diseased states (pathological tetanus), and under the in- 
fluence of certain poisons, especially strychnine. If a frog 
ora warm-blooded animal be given a dose of the latter drug, 
a stimulus, such as normally would excite only limited 
orderly reflexes, will excite the whole cord, and lead to 
discharges along all the efferent fibres so that general con- 
vulsions result, It has been clearly proved that, in sack. 








CONDUCTION IN THE CORD. $79 


the influence of strychnine and in pathological tetanus (as 
observed, for example, in hydrophobia) the conduetivity of 
the whole gray matter is so increased that all paths 
through it are easy, and so # feeble afferent impulse spreads 
in all directions. 

To account for the phenomena of localized skin sensa- 
tions (p, 559) and of limited voluntary movements we must 
make a similar hypothesis. If the nervous impulses enter- 
ing the gray network when the tip of a finger is touched 
spread all through it irregularly, we could not tell what 
region of the skin had been stimulated, for the central 
results of stimulating the most varied peripheral parts 
would be the same. From each region of the gray network 
of the cord where a sensory skin-nerve enters there must, 
therefore, be a special path of conduction to a given brain- 
region, producing results which differ recognizably in con- 
sciousness from those following the stimulation of a differ- 
entskin region. The acuteness of the localizing power will 
largely depend on the definiteness of the path of loast resis- 
tance in the gray matter, since while traveling in a medul- 
lated nerve-fibre from the skin to the cord, or (in the 
white columns) from the gray matter of the latter to the 
brain, the nervous impulse is confined to a definite track, 
Hence anything tending to let the afferent impulse radiate 
when it enters the cord will diminish the accuracy with 
which its peripheral origin can be located. ‘This we see in 
violent pains; a whitlow on the finger affects only a few 
nerve-fibres, but gives rise to so powerful nerve impulses 
that when they reach the cord they spread widely and, break~ 
ing out of the usual track of propagation to the brain, give 
rise to ill-localized feelings of pain often reforred all the 
way up the arm to the elbow. So the pain from one diseased 
tooth is often felt along half a dozen, or all over one side 
of the head. Such cases are comparable to the transforma- 
tion of an orderly reflex into a general convulsion when the 
stimulus increases, 

As an animal shows no spontaneous movements whon its 
cerebral homispheres are removed, we conclude that the 
herve impulses giving rise to such movements start in those 








THE INHIBITION OF REFLEX ACTIONS. 581 


desired to move, to others. But with practice the indepen- 
dent movements become easy. So, too, the localizing power 
of the skincan be greatly increased by exercise (p. 560) as 
one sees in blind persons, who often can distinguish two 
stimuli on parts of the skin which are so near together as to 
give only one sensation to other people. Such phenomena 
dopend on the fact that the more often a nervous impulse has 
traveled along a given road in the gray matter, the easier 
does its path become, and the less does it tend to wander 
from it into others. We may compare the gray matter toa 
thicket; persona seeking to beat a road through from one 
point to another would keep the same general direction, 
determined by the larger obstacles in the way, but all would 
diverge more or less from the straight path on aceount of 
undergrowth, tree trunks, ete., and would meet with consid- 
erable difficulty in their progress. After some hundreds had 
passed, however, a tolerably beaten track would be marked 
out, along which travel was easy and all after-eomers would 
take it. If instead of one entry and one exit we imagine 
thousands of each, and that the paths between certain have 
been often traveled, others less, and some hardly ut all, we 
get a pretty good mental picture of what happens in the 
passage of nervous impulses through the gray matter of the 
cord; the clearing of the more trodden paths answering to 
the effects of use and practice. ‘The human cord and that 
of the frog must not, however, be looked upon as pathless 
thickets at the commencement; each individual inherits 
certain paths of least resistance determined by the structure 
of the cord, which is the transmitted material result of the 
life experience of a long line of ancestry. 

The Inhibition of Reflexes. Since it is possible, ua by 
strychnine, to diminish the resistance in the gray matter, it 
ts conceivably also possible to increase it, and diminish or pre- 
vent reflexes. Such is found to be actually the case. We oan 
to a great extent control refloxes by the will; for example, 
the jerking of the muscles which tends to follow tickling: 
and itis found that after a frog’s brain is removed it is much 
easier to get reflex actions ont of the spinal cord. Certain 
drugs, as bromide of potassinm, also diminish reflex excita. 








PSYCHICAL ACTIVITIES OF TAB SPINAL CORD. 583 


acidulated paper be put on a decapitated frog’s thigh, the 
animal will bend its knee and use its leg to brush off the 
irritant; always using this same leg if the stimulus be not 
so strong as to produce disorderly reflexes, If now the 
foot be tied down so that the frog cannot raise it, after a 
few ineffectual efforts it will move the other Jeg, and may 
wipe the paper off with it, This it has been said shows a 
true psychical activity in the cord; a conscious and yolan- 
tary employment of new procedures under unusual cireum- 
stances. But a close observation of the phenomenon shows 
that. it will hardly bear this interpretation; the movements 
of the other logsue very irregular and inco-ordinate, and 
much resemble reflex convulsions stirred up by the pro- 
longed action of the acid, which goes on stimulating the 
skin nerves more and more powerfully. Even if new 
muscles came, in an orderly way, into play under the 
stronger stimulus, that would not prove a volitional con- 
scious use of them; we see quite similar phenomena when 
there is nothing purpose-like in the movement, Many 
dogs reflexly kick violently the hind leg of the same 
side when one flank is tickled. If this leg be held and 
the tickling continued, very frequently the opposite hind 
leg will take on the movements, which it never does in 
ordinary circumstances, This is quite comparable to the 
frog's use of its other leg under the circumstances aboye 
described, but here it would be obviously absurd to talk of 
a volitional source for such a senseless movement, 

Putting together, then, the testimony of persons with 
injured spinal cords, and the observations made on them 
and on animals, we may tolerably safely conclude that the 
cord contains no centres of consciousness. There are, how- 
ever, persons who maintain that in such cases the cord itself 
feels though the individual does not, whatever that may 
mean; if the statement is used merely to imply that the 
cord is irritable (just as a muscle is) no one denies it; but 
it is an unnecessarily confusing method of stating the fact. 

The Cord as a Transmitter of Nervous Impulises. In 
the gray substance, as we have seen, there is reason to 
believe that nervous impulses can.pass in all directions, 





CEREBRAL FUNCTIONS. 585 


non-mental, duties. If the cerebral hemispheres be re- 
moved from # frog, the animal can till perform every 
movement 28 Well as before; but it no longer performs 
any spontaneously; it must be aroused by an immediately 
acting stimulus, and its response to this is as invariable 
and predicable as that of a frog with its spinal cord only. 
The movements which can be educed are, however, fur 
more complex; instead of mere kicks in various directions 
the animal can walk, leap, swim, got off its back on to its 
feet, and soon. Similar results are observable in pigeons 
whose fore-brain has been removed; mammals bear the 
operation badly, but some, as rats, survive it several hours 
and then exhibitlike phenomena. The creatures can move, 
but do not unless directly stimulated; all their volitional 
spontaneity is lost, and, apparently, all perceptions also; 
they start at a lond noise, bat do not run away as if they 
conceived danger; they follow a light with the eyes, but do 
not-attempt to eseapea hand stretehed forth to cateh them; 
they can and do swallow food placed in the mouth, but 
would die of starvation if left alone with plenty of it about 
them, the sight of edible things seeming to arouse no idea 
or conception. It may be doubted, perhaps, whether the 
animals have any true sensations; they start at sounds, 
avoid opaque objects in their road, and cry when pinched; 
but all these may be unconscious reflex acts: on the whole 
it seems more probable, however, that they have sensations 
but not perceptions; they feel redness and blueness, hard- 
ness and softness, and so on; but sensations, as already 
pointed out, tell in themselves nothing; they are bat signs 
which have to be mentally interpreted as indications of ex- 
ternal objects: it is this interpreting power which seems 
deficient in the animal deprived of its fore brain. 
Functions of the Medulla Oblongata, This contains 
the paths of conduction between the parts of the brain in 
front of it and the spinal cord. It is also the seat of 
many important reflex and automatic centres, especially 
those governing the organs immediately concerned in the 
maintenance of life; as the respiratory, circulatory, and 
masticatory. It may therefore be called the “ nerve cen- 








— FUNCTIONS OF CEREBELLUM. 587 


of the corpora quadrigemina in man are uncertain. The 
cerebellum is the chief organ of combined muscular move- 
ments; it is the main seat of what we may call acquired 
refiexes. Every one has to learn to stand, walk, run, and 
soon; at first all are difficult, but after a time become easy 
and are performed unconsciously. In standing or walking 
yery many muscles are concerned, and if the mind had all 
the time to look directly after them we could do nothing 
else at the same time; we have forgotten how we learnt to 
walk, but in acquiring a new mode of progression in Jater 
years, as skating, we find that at first it needs all our atten- 
tion, but when once learnt we have only to start the series of 
movements and they are almost unconsciously carried on for 
us. At first we had to learn to contract certain muscle 
groups when we got particular sensations, either tactile, 
from the soles, or muscular, from the general position of 
the limbs, or visual, or others (equilibrium sensations, see 
below) from the semicircular canals, But the oftener a 
given group of sensations has been followed by a given 
muscular contraction the more close becomes tho associ- 
tion of the two; the path of connection between the 
afferent and efferent fibres becomes easier the more it is 
traveled, and at last the sensations arouse the proper-move- 
ment without yolitional interference at all, and while 
hardly exciting any consciousness; we can then walk or skate 
without thinking about it. The will, which had at first to 
excite the proper muscular nerve-centres in accordance 
with the felt directing sensations, now has no more trouble 
in the matter; the afferent impulses stimulate the proper 
motor centres in an unconscious and unheeded way. Injury 
or disease of the cerebellum produces great disturbances 
of locomotion and insecurity in maintaining various pos- 
tures, After a time the animals (birds, which bear the 
operation best) can walk again, and fly, but they soon become 
fatigued, probably because the movements require close 
mental attention and direction all the time. 

Sonsations of Equilibrium. The semicircular canals 
have probably nothing to do with hearing. An old view was 
that, lying in three planes at right angles to one another, 








EQUILIBRIUM SENSATIONS. 589 


afferent. impulses, which change the condition of the 
co-ordinating locomotor centres, with every position of the 
head. Or, movements of the endolymph m relation to the 
wall of the canal may be the stimulus, the current swaying 
the projecting hairs (Fig. 149).* Place a few small. bits of 
cork in a tumbler of water, and rotate the tumbler; at first 
the water does not. move with it; then it begins to go im 
the same direction, but more slowly; and, finally, moves at 
the same angular velocity as the tumbler, Then stop the 
tumbler, and the water will go on rotating for some time, 
Now if the head be turned in a horizontal plane similar 
phenomena will occur in the endolymph of the horizontal 
canal; if it be bent sidewise in the vertical plane, in the 
anterior vertical canal; and if nodded, in the posterior verti- 
cal; the hairs moving with the canal would meet the more 
stationary water and be pushed and so, possibly, excite the 
nerves at the deep ends of the cells which bear them, and gen- 
erate afferent impulses which will cause the general nerve- 
centres of bodily equilibration to be differently acted upon 
in each caso. Under ordinary cireumstances the results of 
these impulses do not become prominent in consciousness 
as sensations; but they sometimes may. If one spins round 
for a time, the endolymph takes up the movement of the 
canals, as the water in the tumbler does that of the glass; 
on stopping, the liquid still goes on moving and stimulates 
the hairs which are now stationary; and we feel giddy, 
from the ears tellmg us we are rotating and the eyes that 
we are not; hence difficulty in standing erect or walking 
straight. A common trick illustrates this very well; make 
a person place his forehead on the handle of an umbrella, 
the other end of which 1s on the floor, and then walk three 
or four times round it, rise, and try to go out of a door 
he will nearly always fail, being unable to combine his 
muscles properly on account of the conflicting afferent 
impulses, If a person, with eyes shut, be laid on # hori- 
zontal table which is turned, he can ut first feel and tell the 
direction of the rotation; as it continues he loses the feeling, 
and when the movement stops feels as if he were being turned 


* Page 542, 








FUNCTIONS OF THE FORE-BRALN. 591 


exercised by the fore-brain on the lower centres is at least 
as important as its power of exciting them; strength of 
character depends, perhaps, more on great inhibitory power 
in the fore-brain than on its initiating faculty. 

‘The intellectual powers seem mainly, if not entirely, de- 
pendent for their necessary material antecedents or con- 
comitants on the surfuce convolutions of the cerebral 
hemispheres; if these alone be removed from an animal its 
mental condition is much the same as if the whole fore- 
brain be taken away. Some simple and fundamental 
perceptions seem, however, to remain, having, perhaps, 
their seats in the deeper gray masses constituting the 
optic thalami and corpora striata (p. 167); a dog, from 
which the greater part of the cerebral surfaces had been re- 
moved, after a time learnt to walk about, apparently volun- 
tarily, and to find and eat his food; he even learnt not to 
take the bones of other dogs after ho had eoveral times been 
severely bitten for so doing. But more complex perceptions 
were lost; before the operation, for example, he was violently 
terrified by zeeing a man fantastically dressed; but after- 
wards no such things seemed to arouse in him so complex 
a conception as that of a strange or dangerous object. 

Although the fore-brain is the seat of consciousness it is 
itself insensible to cutting or wounding; and was long 
supposed to be entirely inexcitable by general nerve stimuli, 
It has, however, been found that tolerably powerful electri- 
cal currents applied to the convolutions produce, in many 
cases, definite movements; the nature of the movement 
depending upon the area stimulated. Hence an attempt 
hus been made to detect the functions of different parts of 
the cerebral hemispheres by observing the results of stimu- 
lating each; and provisionally we may, perhaps, assume that 
the brain-centres, from which volitional impulses proceed to 
the co-ordinating centres for the muscle groups called into 
play, lie in the cerebral regions whose stimulation is followed 
by the movement. ‘The animals, however, so often recover 
the power of executing the movement spontaneously after 
its supposed volitional centre has been removed that the 
proper interpretation of the experimental resulta ia etill 








IMPORTANCE OF EXERCISING THE BRAIN, 0S 


Movements which are commonly executed together tend 
to become so associated that it is difficult to perform one 
alone; many persons, ¢.g., cannot close one eye and keep 
the other open. From frequent use, the paths of con- 
duction between the co-ordinating centres for both 
of muscles have become so easy that « volitional impulse 
reaching one centre spreads to the other and excites both. 
‘This association of movements, dependent on the modifica- 
tion of brain structure by use, finds an interesting parallel 
in the psychological phenomenon known as the association 
of ideas; and all education is largely based on the fact that 
the more often brain regions have acted together the moro 
readily, until finally almost indissolubly, do they so act. If 
we always train up the child to associate feelings of disguat 
with wrong actions and of approbation with right, when he 
is old he will find it very hard to do otherwise: such an 
organic nexus will have been established that the activity 
of the one set of centres will lead to an excitation of that 
which habit has always associated with it. ‘The nerve-centres 
are throughout eminently plastic; every thought leaves its 
trace for good or ill; and the moral traism that the more 
often we yield to temptation—the more often an evil solici- 
tation, sensory or otherwise, has resulted in a wrong act— 
the harder it is to resist it, has its parallel (and we can 
hardly doubt its physical antecedent) in the marking out of 
a path of easier conduction from perceptive to volitional 
centres in the brain. The knowledge that every weak 
yielding degrades our brain structure and leayes its trail in 
that organ through which mun is the ‘* paragon of animals,”” 
while every resistance makes less close the bond between 
the thought and the act forall future time, ought surely to 
‘‘give us pause: on the other hand, every right action 
helps to establish a “path of least resistance,” and makes 
its subsequent performance easier. 

‘The brain, like the muscles, is improved and strengthened 
by exercize and injured by overwork or idleness; and just 
4s 4 man may specially develop one set of muscles and 
neglect the rest until they degenerate, so he may do with 
his brain; developing one set of intellectual faculties and 








CHAPTER XXXVI. 
VOICE AND SPEECH. 


Voico consists of sounds produced by the vibrations of 
two elastic bands, the ¢rue vocal cords, placed in the larynz, 
an upper modified portion of the passage which leads from 
the pharynx to the lungs. When the vocal cords are put 
in a certain position, air driven past them sets them in 
periodic vibration, and they emit a musical note; the 
lungs and respiratory muscles are, therefore, accessory 
parta of tho vocal apparatus: the strength of the blast pro- 
duced by them determines the loudness of the voice. The 
larynx itself is the essential voice-organ: its size primarily 
determines the pitch of the voice, which is lower the longer 
the vocal cords; and, hence, shrilfin children, and usually 
higher pitched in women than in men; the male larynx grows 
rapidly at commencing manhood, causing the change com- 
monly known as the “ breaking of the voice.” Every voice, 
while its general pitch is dependent on the length of the 
vocal cords, has, howover, » certain rango, within limits 
which determine whether it shall be soprano, mezzo-soprano, 
alto, tenor, baritone, or bass. This variety is produced by 
muscles within the larynx which alter tho tension of the 
yocal cords, Those characters of voice which we express 
by such phrases as harsh, sweet, or sympathetic, depend 
on the structure of the vocal cords of the individual; cords 
which in vibrating emit only harmonic partial tones 
(p. 547) are pleasant; while those in which inharmonic 
partials are conspicuous are disagreeable. 

The vocal cords alone would produce but feeble sounds; 
those that they omit are strengthened by sympathetic re- 
eonance of the air in the pharynx and month, the action of 





which may epee A bageato 

violin. By movements of throat, tongue, 

and lips the sounds emitted from the larynx are. 

or supplemented in various ways, and converted into 
articulate language or speech, 

‘Tho Larynx lies in front of the neck, beneath the i 
bone and above the windpipe; in many persons is 
prominent, cansing the projection Known as ‘ Adam’s 
apple.” It consists of a framework of partly 
joined by true synovial joints and partly together 

Cs 


cartilages of tho 


cori ile inferior, hora of 


‘aro inserted; 09, 
muscles are added which move the car- 
nce to one another; and the whole is lined 
by a mucous membrane. 
‘Tho cartilages of the larynx (Fig. 156) are nine in number; 
three single and median, and three pairs. ‘The largest (@) 
th nd consists of two halves which meet 
ut separate behind so as to inclose a 
Vv. shaped space, in which most of the remaining 
lie. The epigioftis (not represented in the figure) is fixed 
to the top of the thyroid cartilage and overhangs the entry 





ANATOMY OF LARYNX. 507 


from the pharynx to the larynx (e, Fig. 89);* it may be 
seen, covered by mucous membrane, projecting at the base 
of the tongue, if the latter be pushed down while the 
mouth is held open in front of a glass; and is, similarly 
covered, represented, as seen from behind, at a in Fig. 167. 
‘The cricoid, the last of the unpaired cartilages, is the shape 
of u signet-ring; its broad part (,,, Fig. 156) is on the pos- 
terior side and lies at the lower purt of the opening between 
the halves of the thyroid; in front and on the sides it is 
narrow, and a space, occupied by the erico-thyroid mem- 
brane, intervenes between its upper border and the lower 
edge of the thyroid cartilage. The angles of the latter 
are produced above and below into projecting jorns 
(Cs and Ci, Fig. 156), and the lower horn on each side 
forms a joint with the ericoid. The thyroid can be ro- 
tated onan axis, passing through the joints on each side, and 
rolled down so that its lower front edge shall come nearer 
the cricoid cartilage, the membrane there intervening being 
folded. The arytenoids (+, Fig. 156) are the largest of the 
paired cartilages; they are seated on the upper edge of the 
posterior wide portion of the cricoid, and form true joints 
with it, Each is pyramidal with a triangular baso, and has 
on its tip a small nodule (co, Pig. 156), the cartilage of 
Santorint. From the tip of each arytenoid cartilage the 
aryteno-opiglottidean fold of mucous membrane (10, Fig. 
157) extends to the epiglottis; the cartilage of Santorini 
causes a projection (8, Fig. 157) in this; and a little 
farther on (9) is a similar eminence on each side, caused 
by the remaining pair of cartilages, known as the cunctform, 
or cartilages of Wrisberg. 

Tho Vocal Cords are bands of elastic tissue which reach 
from the inner angle (Pv, Fig. 156) of the base of each 
arytenoid cartilage to the angle on the inside of the thyroid 
where the sides of the V unite; they thus meet in front but 
ure separated at their other ends, The corda are not, how- 
ever, bare strings, like those ofa harp, but covered over with 
the lining mucous membrane of the larynx, a slit, called 
the glottis (c, Fig. 157), being left between them. It is the 


* Page 309. 








projecting cushions formed ty thom om nh ide of 
slit which are set in vibration during 

each vocal cord is a depression, ppc eee opr 
(%, Big. 157); this is bounded above by a somewhat promi- 


rand lower 


ects ihe ere aoa seperate De 
i — 


Sete 
pratin corde, & the ventricles of (8. 

upper eden, cm off froin Uo eniinenoes are the 

nent edge, the false vocal cord. Over most of the interior 
of the larynx its mucous membrane is thick and covered by 
ciliated epithelium, and has many mucous glands im- 
bedded init. Over the vocal cords, however, it is 

sented only by a thin layer of flat non-ciliated cells, and 





MOVEMENTS OF LARYNX. 


contains no glands, Tn quiet breathing, and after death, 
the free inner edges of the yooal cords are thick and rounded, 
and seem very unsuitable for being readily set in vibration. 
‘They are also tolerably widely separated behind, the aryten- 
oid cartilages, to which their posterior ends are attached, 
being separated. Air under these conditions passes through 
without producing voice. If they are watched with the 
laryngoscope daring phonation, it is seen that the cords 
approximate behind so as to narrow the glottis; at the same 
time they become more tense, and their inner edges project 
more sharply and form a better-defined margin to the 
glottis, and their vibrations can be seen, These changes 
are brought about by the delicately co-ordinated activity of 
a number of small muscles, which move the cartilages to 
which the cords are fixed, 

‘The Muscles of the Larynx. In describing the direc- 
tion and action of these it is convenient to use the words 
front or anterior and back or posterior with reference to 
the larynx itself (that is as equivalent to ventral and dorsal) 
und not with reference to the head, as nsual. The base of 
each arytenoid cartilage is triangular and fits on a surface 
of the cricoid, on which it can slip to and fro to some ex- 
tent, the ligaments of the joint being lax. One corner of 
the triangular base is directed inwards and forwards (i.e. 
towards the thyroid) and is called the vocal process (Pr, 
Fig. 156), as to it the vocal cords are fixed. The outer 
posterior angle (Pm, Fig. 156) has several muscles inserted 
on it and is called the muscular process. If it be pulled 
back and towards the middle line the arytenoid cartilage 
will rotate on its vertical axis, and roll its rocal processes 
forwards and outwards, and so widen the glottis; the re- 
verse will happen if the muscnlar process bedrawn forwanis. 
The muscle producing the former movement is the posterior 
crico-arylenad (Cap, Fig. 188); it arises from the back of 
the ecricoid cartilage, and narrows to its insertion into the 
muscular process of the arytenoid on the same side, The 
opponent of this mnsele is the lateral crico-arylenoiid, 
which arises from the side of the cricoid cartilage, on its 
inner surface, and passes upwards and backwards to 








TENSION CHANGES IN VOCAL CORDS. 601 


and brought into its state in deep quiet breathing. Other 
muscles approximate the arytenoid cartilages after they 
have been separated. ‘The most important is the fransverse 
arytenoid (A, Pig. 158), which rans across from one ary- 
tenoid cartilage to the other. Another is the oblique ary- 
tenoid (Taep), which rans across the middle line from the 
base of one arytenoid to the tip of the other; thence cer- 
tain fibres continuo in the aryteno-epiglottidean fold (10, 
Fig. 157) to the base of the epiglottis; this, with its fellow, 
thus embraces the whole entry to the larynx; when they 
contract they bend inwards the tips of the arytenoid car- 
tilages, approximate the edges of the aryteno-epiglottidean 
fold, and draw down the epiglottis, and so close the pas- 
sage from the pharynx to the larynx; this is probably their 
chief function. When the epiglottis has been removed, 
food and drink rarely enter the larynx in swallowing, the 
edges of the folds of mucous membrane on its sides being 
80 brought together as to effectually close the aperture be- 
tween them. 

Tnoreased tension of the vocal cords is produced mainly 
by the ertco-thyroid muscles, one of which lies on each side 
of the larynx, over the crico-thyroid membrane, ‘Their 
action may be understood by help of the diagram, Fig. 159, 
in which ¢ represents the thy- 
roid cartilage, ¢ the ericoid, a 
an arytenoid, and ve a vocal 
cord. The muscle in qnestion 
passes obliquely backwards and 
upwanls from near the front 
end of ¢ (to the right in the 
diagram) to ¢, near the pivot 

ich represents the joint be- 
tween the cricoid cartilage and 
the inferior horn of the thyroid). 
When the muscle contracts it 
jrulls ¢ down into the position indicated by the dotted lines 
and stretches the vocal cord, if the arytenoid cartilages be 
kept, by the muscles behind, from slipping forwards at the 
same time. The antagonist of the crico-thyroid is the 





VOWEL SOUNDS. 603 


The range of the human voice is about three 
from f (176 vib. per 1) on the unaccented octave, in male 
Yoices, to gon the thrice accented octave (1584 vib. per 1’), 
in female, Great singers of course go beyond this range; 
basses have been known to take a on the great octave (110 
vib. per 1‘); and Nilsson in “Tl Flauto Magioo” used to take 
fon the fourth aecented octave (2816 vib. per 1"). Mozart 
heard at Parma, in 1770, an Italian songstress whoee voice» 
had the extraordinary range from g in the first accented 
octave (396 vib. per 1") to ¢ on the fifth accented octave 
(4224 vib. per 1’). An ordinary good bass voice has a com- 
pass from f (176 vib. per 1’) to d’’ (594 vib. per 1"); and 
a soprano from b’ (495 vib, per 1") to g’” (1584). 

Vowels are, primarily, compound musical tones (p. 548) 
prodaced in the larynx. Accompanying the primary partial 
of each, which determines its pitch when said or sung, are 
anumber of upper partials, the first five or six being recogni- 
zable in good full voices, Certain of these upper partials 
are reinforced in the mouth to produce one vowel, and others 
for other vowels; so that the various vowel sounds sre really 
musical notes differing from one another in timbre. The 
mouth and throat cavities form an air-chamber above the 
larynx, and this has a note of its own which varies with its 
size and form, as may be observed by opening the mouth 
widely, with the lips retracted and tho cheeks tense; then 
gradually closing it and protruding the lips, meanwhile 
tapping the cheek. As the mouth changes its form the 
note produced changes, tending in general to pass from a 
higher to a lower pitch and suggesting to the ear at the 
same time a change from the sound of & (father) through 6 
(more) to 63 (moor), When the mouth and throat cham- 
bers are so arranged that the air in them has a vibratory 
rate in unison with any partial in the laryngeal tone, 
it will be set in sympathetic vibration, that partial 
will bo strengthened, and the vowel characterized by it 
uttered. As the mouth alters its form, although the same 
note bo still sung, the vowel changes. In the above series 
(A, 6, 00) the tongue is depressed and the cavity forms ono 
chamber; for & this has a wide mouth opening; for 6 it is 





604 THE HUMAN BODY. 


narrowed: for 50 still more narrowed, und the lips protruded 
s0 as to increase the length of the resonance chamber. ‘The 
partial tones reinforced in each case are, according to 
Helmholtz— 


a 


Re: 

In other cases the mouth and throat cavity is partially sub- 
divided, by elevating the tongue, into a wide posterior and 
a narrow anterior part, each of which has its own note; and 
the vowels thus produced owe their character to two rein- 
forced partials. This is the euse with the series & (man), 
e (there) and i (machine). The tones reinforced by reson- 
ance in the mouth being— 


The nsual i of English, as in spiro, is not a trae simple 
vowel but a dipththong, oneal of & (pad) followed by 


c wal sounds the soft palate is raised so 
rin the nose, which, thus, does not take 
For some other sounds 

initial step is, as in the 


the ai air there takes part 
m a special character; this 





Consonants are sounds produced not mainly by the 
vocal cords, but by modifications of the expiratory blast on 
its way through the mouth. The current may be inter- 
rupted and the sound changed by the lips (Jadials); or, at 
or near the teeth, by the tip of the tongue (dentals); or, in 
the throat, by the root of the tongue and the soft palate 
(gutturals). Consonants are also characterized by the kind 
of movement which gives risé to them. In explosives an 
interruption to the passage of the asir-current is suddenly 
interposed or removed (P, T, B, D, K, @). Other con- 
sonants are continuous (as F, 8, R), and may be subdivided 
into—(1) aspirates, characterized by the sound produced by 
a rush of air through a narrow passage, as when the lips are 
approximated (FP), or the teeth (S), or the tongue is brought 
near the palate (Sh), or its tip against the two rows of teeth, 
they not being quite in contact (Th). For L the tongue 
is put against the hard palate and the air escapes on its 
sides, For Ch (as in the proper Scotch pronunciation of 
loch) the passage between the back of the tongue and the 
soft palate is narrowed. To many of the above pure 
consonants answor others, in whose production true vocali- 
zation (i.e. a laryngeal tone) takes a part. F with some 
voice becomes V; 8 becomes Z, Th soft (teeth) becomes Th 
hurd; and Ch becomes Gh. (2) Resonants; these have 
leon referred to ubove. (3) Vibratories (the different 
forms of R), which are due to vibrations of parts bounding 
a constriction put in the course of the air-current. Ordi- 
nary Ris due to vibrations of the tip of the tongue held near 
the hard: palate; and guttural R to vibrations of the uvula 
and parts of the pharynx. 

The consonants may physiologically be classified as in the 
following table (Foster). 


Explosives. Labials, without voice . 
“with voice . 
Denials, without voice 
with voice . 
Guttarale, without voice . 








INDEX. 


Abdomen, contents of, 4. 
Abdominal respiration, 366, 
Abducens nerve, 170, 
Aberration, chomatic, 502. 
Aberration, spherical, 603, 
Absorbents, 329. 

Absorption from intestines, $45 

Absorption of gases, 380, 

Absorption of oxygen by blood, 
382. 

Accelerator nerves of heart, 252 

Accommodation, 498, 

Acetabulum, 79. 

Acid, acetic, 14; butyric, 14; car- 
bonic, see carbon dioxide; for- 
mic, 14; glycero-phosphoric, 
14; glycocholic, 342; lactic, 14: 
oleic, 18; palmitic, 13; sarco- 
lactic, 14, 125; stearic, 18; 
taurocholic, 342. 

Acquired (secondary) reflexes, 
587. 

Action current (negative varia- 
ton), 198, 197, 

Actions, reflex, 182, 674. 

Addison's disease, 333, 

Adenold tissue, 106, 


Adrenals (supra-renal capsules), 
883, 

Advantage of mixed diet, 905 
448. 

Aftor images, 526. 

Ague cake, 836. 





Air, chemical composition of, 
ar. 

Air cells, 854. 

Air, changes produced in by 
breathing, 878, 

Air, complemental, tidal, ete., 
365. 


Air passages, 853, 

Albumin, serum, 57. 
Albuminoids, 11. 

Albuminous bodies, 10. 

Alcohol, 804. 

Alimentary canal, 208, 
Alimentary principles, 203. 
Amonboid cells, 114. 

Amaboid morements, 21, 48. 
Amylolds (carbohydrates), 13, 


Amyloids, digestion of, 335, 341, 
849. 


Anmmia, 59, 

Anatomical systems, 37. 

Anatomy of alimentary canal, 
908; of ear, 535; of eye, 479; 
of joints, 94; of lymphatic sys. 
tem, 320; of muscular system, 
116; of nervous system, 154; of 
respiratory organs, 352; of 
skeleton, 62; of skin, 412; of 
urinary organs, 402; of vascu- 
lar system, 201 

Animal heat, source of, 451. 

Anterior tibial nerve, 211, 

Anvil bone, 527, 








Breast-bone, 71. 

Bronchial arteries, 211. 

Bronchial tubes, 34. 

Bronchus, 854. 

Brunner's glands, 322. 

Buccal cavity, 808. 

Buffy coat on blood clot, 52. 

Caleaneum, 79, 

Camera obscura, 496, 

Canals, semicircular, 580, 587 

Capacity of lungs, 365. 

Capillaries, blood, 211, 217. 

Capillaries, lymphatic, 829. 

Capillary circulation, 227. 

Capsule of Glisson, 826, 

Carbohydrates, see amyloids. 

‘Carbon dioxide, 14; in blood, 
886; production of in muscle, 
430, 


Carbon monoxide hemoglobin, 
398, 

Cardiac muscular tissue, 124. 

Cardiac impulse, 220, 

Cardiac nerves, 248, 

Cardiac orifice of stomach, 317, 

Cardiac plexus, 172, 

Cardio-inhibitory nerves 260, 

Carotid artery, 210. 

Carpus, 79. 

‘Casein, 11. 

Cartilage, 100; articular, 04; elas- 
tc, 106; filro-, 107; histology | 
of, 101; Inter-articular, 107. 

‘Cartilages of larynx, 596, 

Cntaract, 504. 

Catarrh, 256, 

Cauda equina, 161. 





amorboid, 114; cilinted, 

\y division of, 18; diffe- 

rentiation of, 26; growth of, 18. 
‘Coment, of tooth, 811. 

Centre, cardio -inhibitory, 250; 

corebro-spinal, 156; convulsive, 


400; respiratory, 301. 


Cerebral hemispheres, functions 
of, 590, 

‘Cerebro-apinal centre, 5, 156, 

Cerebro-spinal liquid, 168. 

Cervical plexus, 161, 

Cervical vertebrm, 68, 

Characteristics of human skele- 
ton, 84, 

Chemical combinations, energy 
liberated in, 283, 

Chemical composition of body, 8 

Chemical changes in breathed 
air, 873. 

Chemistry, of bile, 342; of blood, 
G7; of bone, 91; of fats, 112; 
of gastric juice, 338; of lymph, 
G1; of muscle, 124, 420; of 


264; of tecth, 312; of urine, 
410; of white Abrous tissue, 
108; of working muscle, 427. 

Chest, Seo Thorax. 

Chondrin, 107, 

Chorda tympani nerve, 271, 

Choroid, 486, 

Chromatic aberration, 502. 

Chyle, 240. 

Chyme, 339. 5 

Ciliary muscle, 491 

Ciliary processes, 486, 

Cilinted cells, 88, 115, 

Circulation, 201, 214; during as- 
phyxia, 401; influence of ne- 
spiratory movements on, 368; 
influence of nerves on, 247; 
portal, 216, 925; renal, 408, 

Circulatory organs, 201. 








Diplos, 91. 
Direction, perception of, 53), 
504. 


Disassimilation, 20. 

Dislocation, 08, 

Dispersion of light, 495. 

Distance, perception of, 580, 554. 

Division of physiological employ- 
ments, 27. 

Dorsal (neural) cavity, 5, 

Dorsal vertebree, 65. 

Drum of ear, 535. 

Ductleas glands, 239 

Duodenum, 320. 

Dura mater, 157, 

Duration of luminous sensations, 


Elastic cartilage, 106, 

Elements found in body, % 

Eliminative (excretory) tissues, 
80. 

Emulsification, 341, 

Enamel, 311, 

Endbalbs, 556. 

Endocardium, 204, 

Endo-lymph, 588, 

Endo-skeleton, 62, 

Energy, conservation of, 280; 
kinetic, 282; lost from body 
daily, 279, 452; of chemical 
affinity, 283; potential, 282; 
muscular, source of, 427; 
source of in body, 288; utili- 
zation of in body, 280, 

Energy-yielding foods, 425, 

836, 


Epidermis, 6, 412. 
Epiglottis, 316, 596. 
Epithelium, 6, 34, 
Epithelium, elated, 115, 


External auditory ‘meatus, 585. 

External ear, 595, 

External respiration, 852. 

Extrinsic reference of sensations, 
476. 

Eye, anatomy of, 479; append- 
ages of, 480; optical defects of, 
502; physiology of, 506; re 
fraction of light in, 497. 

Eyeball, 485. 

Eyeball, muscles of, 453, 

Eyelids, 431, 

Facial nerve, 170. 

False vocal cords, 598. 

Fat, 18, 111. 

Fat, source of in body, 443, 

Fatigue of retina, 524. 

Fatty tissue, 111, 

Fauces, 815, 

Fechner’s law, 473. 

Femoral artery, 211. 

Femur, 79, 88, 

Ferments, 826, 

Fibrin, 11, 51, 58 

Fibrin ferment, 54. 

Fibrinogen, 58. 

Fibrinoplastin, 58. 

Fibro-cartilage, 106. 

Fibula, 7%, 

Fick and Wislecenus, 427. 

Filiform papitlw, 313. 

Flesh foods, 301. 

Follicles of hairs, 415. 

Fontanelles, $8. 

Foods, definition of, 207; energy- 








nerve-fibres, 178; of nose, 569; 
of plain muscular tissue, 123; 
of retina, 487; of skin, 412; of 
small intestine, 820; of spinal 
cord. 177; of stomach, 318; of 
striped muscle, 122; of teeth, 
B11; of tactile organs, 656; of 
tongue, 570; of white fibrous 
tissue, 103. 

Hollow veins, 207. 

Homologies of supporting tissues 
107. 


Homology, 58; of limbs, $0. 


Hydrocarbons, Ste Fats. 

Hydrogen, 9 

Hygiene, 1; of blood, 58; of 
brain, 993; of clothing, 368, 
458; of exercise, 188; of grow- 
ing skeleton, 109; of joints, 98; 
of muscles, 138; of respiration, 
366, 875; of sight, 501; of 
akeleton, 2; of skin, 420; of 
supporting tissues, 109, 

Hyoid bone, 76, 

Hypermetropia, 600, 

Hypoglossal nerve, 171. 

Ideas, association of, 693, 

Tdio-retinal light, 508, 

Heum, 820. 

Tleo-colie valve, 323. 

Hliae artery, 210, 211. 

Ilium, 79. 

Ulusions, sensory, 477. 

Impulse, cardiac, 220, 

Impulse, nervous, 196, 

Tncus, 587, 

Indigestion, 850. 

Inert layer, 228, 

Tuferior laryngeal nerve, 897. 





Taferior maxillary nerve, 170. 
Inferior mesenteric artery, 211. 
Inferior vena cava, 207. 
Inhibition of reflexes, 581. 
Inhibitory nerves, 184. 
Innervation sensatlous, 
Tunominate artery, 210. 
Innominate bone, 79, 
Tnnominate vein, 314. 
Inogen, 125. 
Toorganle constituents of Body, 
uw 


Tnosit, 18. 

Inspiration, how effected, 259. 
Intensity of sensations, 473. 
Interarticular cartilage, 107. 
Intercostal arteries, 211, 
Tntercostal muscles, 361. 
Internal ear, 38, 

Tnternal medium, 40. 
Internal respiration, 852, 380. 
Intervertebral disks, 71, 94. 
Intervertebral foramina, 71, 
Intestinal digestion, 340, 
Intestines, 320, 
Totra-thoracic pressure, 857. 
Intrinsic heart-nerves, 248, 
Tris, 491. 

Irritability, 21. 

Irritability, muscular, 129, 
Trritable tissues, 31, 
Ischium, 79, 

Jaw-bones, 70. 

Jejunum, 320. 

Jelly-like connective tissue, 106. 
Joints, 94. 

Jugular vein, 24. 

Kidneys, 402, 

Kinetic energy, 289, 
Knee-cap or knee-pan, 79, 
Kreatin, 12, 434 

Labyrinth, 528, 

Lachrymal apparatus, 482, 
Lachrymal boue, 76 








Milk, 802, 

Millon's test, 10. 

Mixed diet, advantage of, 03. 

Modality of sensation, 465, 468, 

Modiolus, 540. 

Morula, 26. 

Motion, 14%. 

Motor organs, 118. 

‘Motor tissues, 33, 

Motores ocull, 168, 

Mouth, 308. 

Movements, associated, 593. 

Movements, respiratory, 358. 

Mucin, 12. 

Mucous membranes, 6. 

Macous layer of epidermis, 412. 

Mulberry mass, 36. 

Mumps, 915. 

Muse volutantes, 504. 

Muscle, biceps, 118; cardiac, 124; 
ciliary, 491; stapedius, 538; 
tensor tympan!, 588, 

Muscles, chemistry of, 124; histo- 
logy of, 122; of eyeball, 483; 
of laryox, 690; of respiration, 
859; physiology of, 123; skele 
tal, 117; structure of, 116; 
visceral, 122, 

Muscular sense, 55, 

Muscular tissue, 83, 122, 

Muscular work, 134, 423, 

Myopia, 500, 

Myosin, 11, 125. 

Nails, 417. 

Nasal bone, 76. 

Negative variation, 193, 197. 

Nerve-cells, 175, 

Nerve-centres, 156, 177, 182, 573. 

Nerve-fibres, 33, 173. 

Nerve-fibres, classification of, 184. 

Nerve plexuses, 150, 

Nerve stimuli, 187, 

Norves, 154; cranial, 168, 199; 
cardiac, 248; Jaryngeul, 307; 





615 


respiratory, $90; secretory, 269, 
971; spinal, 160; sympathetic, 
156; thermic, 457; trophic, 
278; + 257, 871; 
vasomotor, 253. 

Nervous impulses, 196. 

Nervous system, anatomy of, 
it 


Nervous system, physiology of, 
190, 
‘Neural tube (dorsal cavity), 5. 


Nodal points of eye, 606. 

Noises, 542, 

Non-vascular tissues, 41. 

Notes, musical, 642. 

Nucleolus, 17. 

Nucleus, 17. 

Nutrition, 423, 

Nutritive tissues, 30, 

Oceipitat bone, 75. 

Oculo-motor nerves, 168, 

Odorous bodies, 570, 

(Beophagus, 317. 

Oleeranon, 82, 

Oleln, 13, 

Olfactory lobe, 168. 

Olfactory nerves, 163, 

Olfactory organs, 660, 

Omentum, 317, 

Ophthalmic nerve, 170, 

Optical defects of eye, 500, 602. 

Optic nerves, 168, 

Optic thalami, 163. 

Organ of Corti, 541. 

, 2, 34; of animal life, 

114; of circulation, 201; of 
common searation, 468; of 
digestion, 308; of movement, 
118; of relation, 114; of respi 








Portal vein, 824. 

Posterior tibial urtery, 211. 

Postures, 149, 

Potatoes, 803. 

Potential energy, 282. 

Pressure, (ntra-thoracie, 357. 

Pressure sense, S53, 

Primates, 3. 

Production of hent in Body, 449. 

Pronation, 98. 

Proofs of cir nlation, 205. 

Protective tissues, 34. 

Proteids, 10. 

Proteids, oxidation of, 427. 

Protoplasm, 24. 

Psychical activities of cord, 582. 

Psycho-physical law, 478. 

Ptosis, 485. 

Ptyalin, 233. 

Pulmonary circulation, 214, 

Petmonary artery, 206, 

Pulmonary veins, 207, 

Pulse, 240. 

Purkinjo’s experiment, 00. 

Pus, 48. 

Pylorus, 817, 319, 

Pyramids of Malpighi, 400, 

Qualities of sensation, 46%. 

Quantity of blood, 59. 

Quantity of foed needed aaily, 
‘BOG, 48, 

Radial urtery, 210, 

Rudio-uloar articulution, 07, 

Radins, 78, 

Range of voice, 005, 

Rate of blood flow, 242, 

Reeeptaculum chyli, 390. 

Receptive tissues, 80, 

Rectum, 322, 

Red blood corpuscles, 44. 59 

Reduced heme ay 

Reflex actions, 182, 

Reflex convulsions, 

Reflexes, acquired, 587. 





617 


Refracting media of eyo, 490. 
Refmetion by lenses, 496. 
Refraction of light, 493, 
Refraction in the eyo, 407. 


Reproduction, 19, 
Reproductive tissues, 34. 
Residual air, 365. 
Resistance theory, 395. 
Resonance, sympathetic, 549, 
Respiration, 20, 352. 
Respirntion, chemistry of. 379. 
Respiration, nerves of, 300, 
Respiratory centre, 391. 
Respiratory foods, 426. 
Respiratory movements, 357, 
Respiratory sounde, 365. 
Reticular membrane, 541. 
Retiform (adenoid) connective 
tissue, 106. 


| Retina, 487. 


Rhythmic movements, 393. 
Ribs, 72, 

Rib cartilage, 72. 

Rice, 303, 

Right lymphatic duct, 390. 
igor mortis, 430, 

Rods and cones, 488, 568, 
Round foramen, 536, 
Ranning, 153. 

Sacoulus, 539, 

Sacral plexus, 162. 

Sacral vertebne, 60, 

Saliva, uses of, 834. 
Salivary glands, 315, 
Salivary glands, nerves of, 270. 
Salivin (ptyalin), 385, 
Santorini, cartilages of, L87 
Sarcolactic acid, 14, 125, 
Sarcolemma, 123, 








AIS INDEX. 


peala of cochlea, S40 





aude, 418. 


seeondary aquired) retlexes, 
aT, 





















of equilibrium. 
of thirst. 
rnee of, AB4L, 
of, 465, 













smoid flexure, 823. 

Size, perception of, 531 

Skeleton, 62: appendic 
axial. 63. 67; of fac 
skull, 76, peculiaritit 
man, “4: of thorax. 8 

Skin, 6, 412: glands of, 
giene of, 490; nerve 
in, 556. 

Skull. 72. 

Small intestine, 320. 

Smell, 567. 

Sneezing, 402. 

Solar plexus, 172. 

Solar spectrum, 495. 

Solidity, visual percep 
333. 

Sounds, 542. 

Sounds of the heart, 222. 

Sounds, respiratory, 365. 

Source of animal heat, 4 

Source of fats, 441. 

Source of glycogen, 40. 

Source of museulur work 

Source of urea, 433. 

Sources of energy to Bod 

















Sphenoid bone, 75. 

Spherical aberration, 508, 

Spinal cord, 158; conduc 
57X, 683; functions of, 1 
histology of, 177; mer 
of 157; psychical activ 
582, 

Spinul accessory nerve, 1 

Spinal marrow. See Spin 

Spinal nerves, 160. 

inal nerve-roots, 160, 1! 

pleen, 342. 

Kpontancity, 28. 

Sporadie guoglia, 178. 





INDEX, 


Sprains, 99, | 

Squinting, 434. | 

Stapedius muscle, 538. 

Stapes, 587. 

Starch, 803; digestion of, 38%. 

Starvation, proteid, 436, 

Stationary air, 985. 

Stereoscopic vision, 523, 

Sternum, 71. 

Stimuli, muscular, 129; nervous, 
187. 

Sthmulus, 21, 

Stirrup-bone, 537. 

Stomuch, 317. 

Stomata, lymphatic, 330, 

Storge tissues, 81, 437. 

Strabismus (squinting), 484 

Structure of bone, 86, 

Strychnine poisoning, 577. 

Subelavian artery, 210, 

Subcutancous arvolar tissue, 414, 

Sublingual gland, $15. 

Submaxillary gland, 271, 315, 

‘Sucens entericus, 344, 

Sudoriparous glands, 417. 

Superior Jnryngeal nerve, 897. 

Superior maxillary nerve, 170, 

Superior mesenteric artery, 211. 

Supination, 98, 

Supplemental air, 365. 

Supporting tissues, 20. 

Supra-rennl capsules, 238%, 

Sutures, 93, 

Swallowing, 386, 

Sweat, 418. 


eatglands, 407. 
Sweat-glands, nerves of, 270 


Sympathetic resonance, 549. 

Sympathetic resonance in ear, | 
‘655. 

Synovial membranes, 95. 


610 


Syntonin, 126. 

‘System, alimentary, 308; clreula- 
tory, 201; muscular, 116, 128; 
nervous, 123, 154; osseous, 63; 
respiratory, 354; renal, 405, 

Systemic cireulation, 215. 


Tear-glands, 482, 

‘Tectorial membrane, 542. 

‘Teeth, 809. 

‘Teeth, structure of, 811, 

‘Temperature of Body, 450. 

Temperature, bodily, regulation 
of, 454. 

‘Temperature sense, 562, 

‘Temperatures, local, 455, 

‘Temporal artery, 210. 

Temporal bone, 75, 

‘Tension of blood gases, 282, 

‘Tendons, 118, 

‘Tonsor tympani muselo, 58. 

‘Tests for protelda, 10, 

Tetanus, 132, 

Theory, resistance, 395. 

Theory of color vision, 519. 

Thermic nerves, 457, 

Thigh-bone, 79. 

‘Thirst, 560, 

‘Thoracic duct, 829. 

Thorax, aspiration of, #07; con- 
tents of, 4; movements of in 
respiration, 850; skeleton of, 
*i0, 

‘Throat, 316, 

‘Thyroid body, 883. 

Thyroid cartilage, 590. 

‘Thyroid foramen, 79. 

‘Thymus, 833, 

‘Tibia, 79, 








INDEX. 


Visual axis, 518 

Visual contrasts, 525. 

Visual perceptions, 530, 

Visual sensations, 506, 519: dura- 
tion of, 516; intensity of, 513. 

Vital capacity, 366. 

Vitreous humor, 491. 

Vocal cords, 597. 

Vocal cords, false, 598. 

Voice, 595, 

Vomer, 76, 

Vowels, 608. 

Walking, 151. 

Wandering cells, 106, 

Warm-blooded animals, 449. 

Water, constituent, 25. 

Water, percentage of, in Body, 
iM 





Waxing kernels, 880. 

Weber's schema, 293. 

Weber's law, 478. 

‘Wheat, 302. 

Whipped blood, 51, 

White blood corpuscles, 17, 47, 
59, 

White fibrous tissue, 108, 

Windpipe, 354. 

Wrisberg, cartilage of, 597. 

Wrist, 79, 

Xantho-proteic test, 10, 

Yawning, 402. 

Young’s theory of color vision, 
‘519. 

Zoological position of man, 2 

Zymogen, 268, 





APPENDIX. 
REPRODUCTION AND DEVELOPMENT. 


Reproduction in General. In all cases reproduction 
consists, essentially, in the separation of a portion of living 
matter from a parent; the separated part bearing with it, 
or inheriting, certain tendencies to repeat, with more or 
less variation, the life history of its progenitor. In the 
more simple cases a parent merely divides into two or 
more pieces, each resembling itself except in size; these 
then grow and repeat the process; as, for instance, in 
the case of Ameba (see Zoology), and our own white 
blood corpuscles (p. 18). Snch a process may be summed 
up in two words us discontinuous growth; the mass, instead 
of increasing in size withont segmentation, divides as it 
grows, and so forms independent living beings. In somo 
tolerably complex multicellular animals we find essentially 
the same thing; at times certain cells of the fresh-water Po- 
lype (see Zoology) multiply by simple division in the manner 
ubove described, but there is a certain concert between 
thom: they build up « tube projecting from the side of the 
parent, « mouth-opening forms at the distal end of this, 
tentacles sprout ont around it, and only when thus com- 
pletely built up and equipped is the young Hydra set loose 
on its own careor. How closely such a mode of multiplica- 
tion is allied to mere growth is shown by other polypes in 
which the young, thus formed, romain permanently attached 
to the parent stem, so that a compound animal rosults, 
This mode of reproduction (known as gemmation or bud- 
ding) may be compared to the method in which many of 
the ancient Greek colonies were founded; carefully organ- 
ized and prepared at home, they were sent out with a dae 








REPRODUCTION OF TISSUES. 8 


ply and develop. New blood capillaries, however, sprout 
out from the sides of old, and new epidermis seems only 
to be formed by the multiplication of epidermic cells; hence 
the practice, recently adopted by surgeons, of transplanting 
little bits of skin to points on the surface of an extensive 
burn or ulcer. In both blood capillaries and epidermis the 
departure from the primary undifferentiated cell is but 
slight; and, as regards the cuticle, one of the permanent 
physiological characters of the cells of the rete mucosum is 
their multiplication throughout the whole of life; that is 
a main physiological characteristic of the tissue: the same 
is very probably true of the protoplasmic cells forming the 
walls of the capillaries. Nerve-fibres are highly differenti- 
ated, yet nerves rapidly unite after division; this, how- 
ever, occurs by modification of ammboid wandering cells 
(p. 106) which align themselves with them. In Mammals, 
muscular and glandular tissues seem never to be reproduced 
after removal, 

We find, then, as we ascend in the animal scale a dimin- 
ishing reproductive power in the tissues generally: with the 
increasing division of physiological labor, with the changes 
that fit pre-eminently for one work, there is a loss of other 
faculties, and this one among them. The more specialized 
a tissue the less the reproductive power of its elements, and 
the most differentiated tissues are either not reproduced at all 
aftor injury, or only by the specialization of ameboid cells, 
and not by a progenitive activity of survivors of the same 
kind as those destroyed. In none of the higher animals, 
therefore, do we find multiplication by simple division, or 
by budding: no one cell, and no group of cells used for the 
physiological maintenance of the individual, can build up 
a new complete living being; but the continuance of the 
mace is specially provided for by setting apart certain 
cells which shall have this one property—cells whose duty 
is to the species and not to any one representative of it—an 
essentially altraistic clement in the otherwise egoistic whole. 

Sexual Reproduction. In some cases, especially among 
insects, the specialized reproductive cells ean develop, each 
for itself, under suitable conditions, and give rise to new 








STRUOTURE OF THE TESTIS. 5 


—p. 356—round the Tung) and covers the exterior of the 
gland. Between the external and reflected layers of the 
tunica vaginalis is a space containing a small quantity of 


lymph. 
‘The testicles deyelop in the abdominal cavity, and only 
later (though commonly before birth) descend into the 
scrotum, passing through apertures in the muscles, ete., of 
the abdominal wall, and then sliding down, over the front 
of the pubes, beneath the skin. The cavity of the tunica 
Yaginalis at first is a mere offshoot of the peritoneal cavity, 
and its serous membrane is originally a part of the perito- 
neum. In the carly years of life the passage along which 
the testis passes usually becomes nearly closed up, and the 
communication between the peritoneal cavity and that of 
the tunica vaginalis is also obliterated. Traces of this 
passage can, however, readily be observed in male children; 
if the skin inside the thigh be tickled, a muscle lying 
beneath the skin of the scrotum is 
made to contract reflexly, and the 
testisis jorked up some way towards 
the abdomen and quite out of the 
scrotum. Sometimes the passage 
romain permanently open and acoil 
of intestine may descend along it 
and enter the scrotum, constituting 
an inguinal hernia or rupture. A 
hydrocele is an excessive accumula- 
tion of liquid in the serous cavity of 
the tunica vaginalis, 
Beneath its covering of serous 
membrane each testis has a proper 
fibrous tunic of itsown. ‘This forms 
‘a thick mass on the posterior side of 
the gland, from which partitions or 
septa (i, Fig. 160) radiate, subdivid- 
ing the gland into many chambers. In each chamber lie 
several greatly coiled seminiferous tubules, a, a, averaging 
in length 0.68 meters (27 inches) and in diameter only 
0.14mm. (;$5 inch). Their total number in each gland ig 








MALE REPRODUCTIVE ORGANS. 

The male terethra leads from the bladder to the end of 
the penis, where it terminates in an opening, the meatus 
urinarins, It is described by anatomists as made up of three 
portions, the prostatic, the membranous, and the spongy. 
The first is surrounded by the prostate gland and receives 
the ejaculatory ducts, On its posterior wall, close to the 
bladder, is an elevation containing erectile tissue (see below) 
and supposed to be dilated during sexual congress, 0 as to 
ent off the passage to the urinary receptacle. On this crest 
is an opening leading into a small recess, the wéricle, which 
is of interest, since the study of Embryology shows it to be 
an undeveloped male uterus. The succeeding membranous 
portion of the urethra is about 1.8 em. (} inch) long; the 
spongy portion lies in the penis. 

The penis is composed mainly of erectile fissue, i.e. 
tissues so arranged as to inclose cavities which can be dis- 
tended by blood. Covered outside by the skin, internally 
it is made up of three elongated cylindrical masses, two of 
which, the corpora cavernosa, lie on its anterior side; the 
third, the corpus spongiosum, surrounds the urethra and 
lies on the posterior side of the organ for most of its length; 
it, however, alone forms the terminal dilatation, or glans, of 
the penis. Each corpus cavernosum is closely united to its 
fellow in the middle line and extends from the pubic bones, 
to which it is attached behind, to the glans penis in front. 
Tt is enveloped in a dense connective-tissue capsule from 
which numerous bars, containing white fibrous, elastic, and 
unstriped muscular tissues, radiate and intersect in all 
directions, dividing its interior into many irregular cham- 
bers called venous sinuses, Into these arteries convey blood, 
which is carried off by veins springing from them, 

‘The arteries of the penis are supplied with vaso-dilator 
nerves (p. 257), the nervi erigentes, from the sacral plexus 
(p. 162), Under certain conditions these are stimulated 
and, the arteries expanding, blood is poured into the 
yenons sinuses faster than the veins drain it off; the latter 
are probably also at the same time compressed where they 
leave the penis by the contraction of certain muscles passing 
over them; the organ then becomes distended, rigid, and 





FEMALE REPRODUCTIVE ORGANS. 


(60-100 grains). ‘The organs lie in the pelvic cavity 
cnyeloped in a fold of peritoneum (the broad ligament), and 
receive blood-vessels and nerves along one border, From 
time to time ova reach the surface, burst through the envel- 
oping peritoneum, and are received by the wide fringed 
aperture, fi, of the oviduct or Fallopian tube, od. This 
tube narrows towurds its inner end, where it communicates 
with the uterus, and is lined by a mucous membrane, cov- 
ered by ciliated epitheliam; plain muscular tissue is also 
developed in its wall, The uterus (a, c, Fig. 162) is a hol- 
low orgun, with relatively thick muscular walls (left un- 
shaded in the figure) which contains the foetus during 


It, ~The titerus, in section. with the right Fallopian tube and ovary, 
xin frien ochlnk about ithe he hes Upper Part ot uterus: cy i 


pi 
opposite Cy o# faterswm. © upper part of vagina: od, Fallopian tube; 
idbetated extremity; po, parovactian. 


pregnancy and expels it at birth; itliesin the pelvis between 
the urinary bladder and the rectum (Fig. 163); the Fallo- 
pian tubes open into its upper corners, It is free above, 
but its lower end is attached to and projects into the vagina. 
In the fully developed virgin state the organ is somewhat 
pear-shaped, but flattened from before back, about 7.5 
cm. (3 inches) in length, 5 cm, (2 inches) in breadth at 
its upper widest part, and 2.5 cm, (1 inch) in thickness; 
it weighs from 25 to 42 grams (} to lf oz,). The upper wider 
portion of the womb ix knownas its body; the cavity of this 
is produced at each side to mect the openings of the Fallo- 





THE OVARY. un 


brane, and is covered externally by the peritoneum, bands 
of which project from each side of itasthe broad ligaments 
(UW, Fig. 162). Opening on the internal mucous membrane 
are the mouths of closely set, simple or slightly branched, 
tubular glands, 

‘The vagina is a distensible passage, extending from the 
uterus to the exterior; dorsally it rests on the rectum, and 
ventrally is in contact with the bladder and urethra. It is 
lined by mucous membrane, containing mucous glands, and 
outside this is made up of areolar, erectile, and unstriped 
muscular tissues, Around its lower endis a ring of striated 
muscular tissue, the sphincter vagine. 

The vuloa is a general term for all the portions of the 
female generative organs visible from the exterior. Over 
the front of the pelvis the skin is elevated by adipose tissue 
beneath it, and forms the mons Veneris. From this two folds 
of skin (1, Fig. 163), the ladia majora, extend downwards 
and backwards on cach side of a median cleft, beyond which 
theyagain unite. On separating the labia majora ashallow 
genito-urinary sinus, into which the urethra and vagina 
open, is exposed, At the upper portion of this sinus lies 
the clidoris, a small and very sensitive erectile organ, resem- 
bling a miniature penis in structure, except that it has no 
corpus spongiosum and is not traversed by the urethra, 
From the clitoris descend two folds of mucous membrane, 
the nymphe or labia interna, betwoen which is the vestibule, 
a recess containing, above, the opening of the short female 
urethra, and, below, the aperture of the vagina, which is in 
the virgin more or less closed by a thin duplicature of mu- 
cons membrane, the hymen. 

Microscopic Structure of the Ovary. The main mass 
of the ovary consists of a close connective-tissuc stroma, 
containing unstriped muscle, blood-vessela, and nerves: it 
is covered externally by a peculiar germinal epithelium, 
and contains imbedded in it many minute cavities, the 
Graafian follicles, in which ova lic. If a thin section of an 
ovary be examined with the microscope many hundreds of 
small Graafian follicles, cach about 0.25 mm. (phy inch) in 
diameter, will be found imbedded in it near the surface. 








PUBERTY. B 


Puberty. The condition of the reproductive organs of 
each sex described ubove is that found in adults; although 
mapped out, and, to a certain extent, developed before 
birth and during childhood, these parts grow but slowly and 
remain functionally incapable during the early years of life; 
then they comparatively rapidly increase in size and become 
physiologically active: the boy or girl becomes man or 
woman, 

This period of attaming sexual maturity, known as pu- 
berty, takes place from the eleventh to the sixteenth year 
commonly, and is accompanied by changes in many parts 
of the Body. Hair grows more abundantly on the pubes 
and genital organs, and in the armpits; in the male also on 
various parts of the face, The lad’s shoulders broaden; hia 
larynx enlarges, and lengthening of the vocal cords causes 
a fall in the pitch of his voice; all the reproductive organs 
increase in size; fully formed seminal fluid is secreted, 
and erections of the penis occur. As these changes are 
completed spontaneous nocturnal seminal emissions take 
place from time to time during sleep, being usually associ- 
ated with voluptuous dreams. Many ayoung man is alarmed 
by these; he has been kept in ignorance of the whole mut- 
ter, is too bashful to speak of it, and getting some quack 
advertisement thrust into his hand in the street is alarmed 
to learn that his strength is being drained off, and that he 
is on the high-road to idiocy and impotence unless he 
place himself in the hands of the advertiser, Lads at this 
period of life should have been taught that such emissions, 
when not too frequent and not excited by any voluntary act 
of their own, are natural and healthy. They may, however, 
occur too often; if there is any reason to suspect this, the 
family physician should be consulted, as the healthy activity 
of the sexnal organs varies so much in individuals as to make 
it impossible to lay down numerical rules on the subject, 
The best preventives in any case are, however, not drags, 
but an avoidance of too warm and soft a bed, plenty of 
muscular exercise, and keeping out of the way of anything 
likely to excite the sexual instincts. 

In the woman the pelvis enlarges considerably at pubert 








MENSTRUATION. 


broken down, and discharged along with more or less blood, 
constituting the menses, or monthly sickness, which com- 
monly lasts from three to five days. During this time the 
vaginal secretion is also increased, and, mixed with the 
blood discharged, more or less alters its color, and usually 
destroys its coagulating power. Except during pregnancy 
and while suckling, menstruation occurs at the above 
intervals, from puberty np to about the forty-fifth year; 
the periods then become irregular, and finally the discharges 
cease; this is an indication that ovulation has come to 
an end, and the sexual life of the woman is completed. 
‘This time, the climacteric or ** tarn of life,” is a critical 
one; various local disorders are apt to supervenc, and even 
mental derangement. 

Hygiene of Menstruation. During menstruation there 
is apt to be more or less general discomfort and nervous irri- 
tability; the woman is not quite herself, and those respon- 
sible for her happiness ought to watch and tend her with 
special solicitude, forbearance, and tenderness, and protect 
her from anxiety and agitation. Any strong emotion, 
especially of a disagrecable character, is apt to check the 
flow, and this is always liable to be followed by serious cou- 
sequences. A sudden chill often has the same effect; hence 
a menstruating woman onght always to be warmly clad, and 
take more than usual care to avoid draughts or getting wet. 
At these periods, also, the uterus is enlarged and heavy, and 
being (as may be seen in Fig. 163) but slightly supported, 
and that near its lower end, it is especially apt to be dis- 
placed or distorted; it may tilt forwards or sideways (wer- 
sions of the uterus), or be bent where the neck and body of 
the organ meet (flexion). Hence violent exercise at this 
time should be avoided, though there is no reason why a 
properly clad woman should not take her usual daily walke 

Painful menstruation (dysmenorrhwa) may be due to very 
many causes, but it 1s only within recent years that physi- 
cians have come to recognize how often it depends on uterine 
displacements, and in such cases how readily it may usually 
be remedied by restoring the organ to its proper position, 
and supporting it there ifnecessary. A flexion of the org 








CONCEPTION. Ww 


a conservative effort of the system), may be the most aise 
astrous thing to do. 

Imprognation. Ax the ovum descends the Fallopian tbo 
the changes preliminary to menstruation are taking place 
in the uterus, Its mucous membrane is thickened, all the 
generative organs of the woman are more or less congested, 
and her sexual emotions are commonly more easily aroused. 
Unless the act of coition occur all this passes off with the 
menstrual finx, and the organs return to a quiet state until 
the period of the next ovulation. If sexual congress tukes 
place the vagina, uterus, and oyiducts are thrown into 
reflex peristaltic contractions; and there is frequently an 
increased secretion by the vaginal mucous membrane. 
Some of the seminal fluid is received into the uterine cavity, 
and there, or, more probably, in the Fallopian tube, meets 
the ovum. The spermatozoa are carried along partly, 
perhaps, by the contractions of the muscular walls of the 
female cavities, but mainly by their own activity. From 
observations made on various lower animals it appears that 
their moyements cease immediately on coming into contact 
with the ovum, and that one only takes part in fertilization, 
How this latter occurs in the mammalian ovum is not cer- 
tain; observations in other groups make it probable that 
the male element directly fuses in whole or part with the 
protoplasmic mass of the oyum, but no opening has been de- 
teeted in the zona pellucida of the mammalian ovum, which 
is 80 thick and firm that it is hard to imagine a spermato- 
xoon otherwise penetrating it; some, therefore, are inclined 
to suppose that material is merely passed by dialysis from 
the spermatozoon into the egg-cell, 

‘Tho fertilized ovum continues its descent to the uterine 
cavity, but, instead of lying dormant like the unfertilized, 
segments (p. 26), and forms a morula, This, entering the 
womb, becomes imbedded in the soft, thickened, vasoular 
mucous membrane there, from which it imbibes nourish- 
ment, and which, instead of being cast off in a menstrual 
discharge, 18 now retained and grows during the whole of 
pregnancy, haying important duties to discharge in connec- 
tion with the nutrition of the embryo. 





GESTATION. “19 


dergoes a great development in connection with the forma- 
tion of the placenta (see below). Meanwhile the whole uterus 
enlarges; its muscular coat especially thickens. At first 
the organ still lies within the pelvis, where there is but 
little room for it; it accordingly presses. on the bladder and 
rectum (see Pig, 163) and the nerves in the neighborhood, 
frequently causing considerable discomfort or pain; and, 
reflexly, often exciting nausea or vomiting (the morning 
sickness of pregnancy). Later on, the pregnant womb 
escapes higher into the abdominal cavity, and although then 
larger, the soft abdominal walls more readily make room for 
it, and less discomfort is usually felt, though there may be 
shortness of breath and palpitation of the heart from inter- 
ference with the diaphragmatic movements. Ail tight 
garments should at this time be especially avoided; the 
woman’s breathing is already sufficiently impeded, and the 
pressure may also injure the developing child. Meanwhile, 
changes occur elsewhere in the Body, The breasts enlarge 
and hard masses of developing glandular tissue can be felt in 
them; and there may be mental symptoms: depression, 
anxiety, and an emotional nervous state. 

During the whole period of gestation the woman is not 
merely supplying from her blood nutriment for the fotus, 
but also, through her lungs and kidneys, getting rid of its 
wastes; the result is a strain on ber whole system which, it 
is true, she is constructed to bear and will carry well if in 
good health, but which is severely felt if she be feeble or 
suffering from disease. Many a wife who might have led a 
long and happy life is made an invalid or brought to pre- 
mature death, through being kept in a chronic state of 
pregnancy. There is a general agreement that sexual eon- 
tinence is possible and a duty in unmarried men, but the 
husband rarely considers that he should put any bounds on 
himself beyond those indicated by his own passions; consid- 
eration for his wife’s health rarely enters his head in this 
connection. The healthy married woman who endoavors 
to evade motherhood because she thinks she will thus pre- 
serve her personal appearance, or because she dislikes the 
trouble of a family, deserves but little sympathy; she is 








NUTRITION OF THE EMBRYO. 21 


acuteness in him to discover such suffering when it exists, 
nor very much real affection to contro! himself accordingly. 
In the class of cases referred to, rest of the over-irritable 
and congested female organa is above all essential. The 
cause is frequently removable by simple, but skilled, treat- 
ment; the desirability of rendering this available ton 
woman in members of her own sex has already been insisted 
upon. 

Even when no pain is caused harm may be done: the presi- 
dent of the Gynecological Society, in an address delivered 
before that body, lately stated that if either party to a coi- 
tion fails of the orgasm damage is apt to ensue, but eape- 
cially to the woman if she fail; the organs are congested from 
the stimulus of the sexual act and the normal final orgasm 
is required for their healthy relief und return to the resting 
condition. If this be so, it is 
clear that coition should be 
restricted to times when the 
woman's general state encour- 
ages the orgasm, and unless 
she generally experiences it 
sexual congress should be 
avoided until her health is 
restored. 

‘The Fotal Appendages. In 
the earliest stages of life, those 
ocourring in the days imme- — ,,. woatole 
diately after fertilization of the 9. thiamel at distended ann pele 
ovam, there is little or no nlkogeer Lae ve 
growth. The ovum segments = 5 
into a number of cells, but the morula thus formed is little 
larger than the original egg-cell itself. At first it isa solid 
mass (F, Fig, 8, p. 26), bnt its cells soon recede from the 
entre and become arranged (Fig. 165) around a central 
By conning mainly some absorbed liquid; atone point, 

¢ embryonal disk), the layer thickens, and from thence 
thickening spreads, by cell growth and multiplication, 
over the whole sac, which is known as the 
vesicle; the membrane thus formed is the blastoderm, and 





THE FOTAL APPENDAGES. 23 


axis) develop into the walls of chest and abdomen; farther 
out it tarns up and arches over the back of the embryo, and 
its edges, there meeting, grow together and form a bag, the 
anion, enveloping the fotas. Into this a considerable 
quantity of liquid is secreted, in which the festus floats. At 
birth the contractions of the uterus, pressing on the amnion, 
drive part of it down like a wedge into the neck of the 
uterus, and through its liquid contents an equable pressure 
is exerted there, until the os wferi is tolerably dilated; the 
suc then normally ruptures and the “waters” escape. Some- 
times, however, an infant is born still enveloped in the 
amnion, which is then popularly known as a caul. While 
the amnion is developing, a semi-cartilaginous rod forms 
along the axis of the Body beneath the floor of the dorsal 
tube; this is the wofockord; when it appears the young being 
is marked out distinctly as a vertebrate animal, having a dor- 
sal neural fnde above an axial skeleton, and a ventral hemul 
tude (p. 4), formed by the proximal regions of the somato- 
ploure, beneath it. The ventral tube, however, is still widely 
open, the points where the amniotic folds turn back being 
far from meeting in the future middle line of the chest and 
abdomen. 

‘The proximal portions of the pPesicygene incurve to 
inclose the alimentary tube, which is at first straight and 
simple. Beyond the point where it bends in for this purpose 
the splanchnopleure again diverges, und incloses a emall 
globular bag, éhe yelk sac, which is, thus, attached to the 
yontral side of the alimentary canul; it at first projects 
through the opening where the amniotic folds turn back, 
bat has little importance in the mammalian embryo and is 
#00n absorbed. be 

The allantois is primarily an outgrowth from the ali- 
mentary canal, containing blood-vessels, It passes ont from 
the Body on the ventral side where the somatopleures have 
not yet met, and reaching the inside of the uterus, its distal 
ond expands there to make the main part of the placenta (see 
below). Its narrow proximal portion forms umbilical 
cord, around which the somatoploures, in ing to in- 
close the belly, meet at the navel some time before birth. 











Wad hegey 








2 Nutrition of the Embryo. .\ :. 
- aor : tooe? mate: aot 








PARTURITION, 


undergo rapid fatty degeneration and are absorbed, and 
in a few weeks the orgun returns almost to its original 
size. ‘The parturient woman is especially apt to tuke infec- 
tious diseases; and these, should they attack her, are fatal 
in a yery large percentage of cases. Very special care 
should therefore be taken to keep all contagion from 
her, 

There is a current impression that a pregnancy, once 
commenced, can be brought to a premature end, especially 
in its carly stages, without any serious risk to the woman. 
It onght to be widely made known that such a belief ix 
erroneous, Premature delivery, early or late in pregnancy, 
is always more dangerous than natural labor at the proper 
term; the physician has sometimes to mduce it, as when a 
malformed pelvis makes normal parturition impossible, or 
the general derangement of health accompanying the preg- 
nancy 1s such as to threaten the mother’s life; but the ocea- 
sional necessity of deciding whether it is his duty to pro- 
cure an abortion is one of the most serious responsibilities 
he meets with in the course of his professional work. 

Dr. Storer, an eminent gynwcologist, states emphatically, 
from extended observation, that ‘despite apparent and 
isolated instances to the contrary— 

1. A larger proportion of women die during or in con- 
sequence of un abortion, than during or in consequence of 
child-bed at the fall term of pregnancy: 

3. A very much larger number of women become con- 
firmed invalids, perhaps for life; and— 

3. The tendency to serious and often fatal organic disease, 
48 cancer, 1s rendered very much greater at the so-called 
“turn of life,” by previous artificially induced premature 
delivery, 

Daring pregnancy there is a close connection between 
the placenta and uterus; nature makes preparation for the 
safe dissolution of this at the end of the normal period, 
but ‘its promature rupture is usually attended by pro- 
fuse hemorrhage, often fatal, often persistent ton greater or 
less degree for many months after the act is completed, and 
always attended with more or less « 
avetem, oven though the full ! of tl not noted for: 








LACTATION, 


established, The oil-globules of the milk are formed by a 
sort of fatty degeneration of the glaud-cells, which finally 
full to pieces; the cream is thus set free in the watery and 
albuminous secretion formed simultaneously, while newly 
developed gland-cells take the place of those destroyed. In 
the milk first secreted after accouchment (the colostrum) the 
cell destruction is incomplete, and many cells still float in the 
liquid, which has a yellowish color; this first milk acts as a 
purgative on the infant, and probably thus serves a useful 
purpose, a8 a certain amount of substances (biliary and 
other), excreted by its organs during development, are found 
in the intestines at birth. 

. Human milk is undoubtedly the best food for an infant 
in the early months of life; and to suckle her child is useful 
to the mother if she be a healthy woman. There is reason 
to believe that the processes of mvolution by which the large 
mass of muscular and other tissues developed in the uterine 
walls during pregnancy are broken down and absorbed, 
take place more safely to health if the natural milk secretion 
is encouraged. Many women refuse to suckle their children 
from a belief that so doing will injure their personal appear- 
ane, but skilled medical opinion is to the co atrary effect; 
the natural course of events is the best for this purpose, 
unless lactation be too prolonged. Of course in many cases 
there are justifiable grounds for « mother’s not undertaking 
this part of her duties; a physician is the proper person to 
dovide. 

Ina healthy woman, not suckling her child, cvulation and 
menstruation recommence about aix weeks after childbirth; 
4 nursing mother usually does not menstruate for ten or 
twelve months; the infant should then be weaned. 

When an infant cannot be suckled by its mother ora wet~ 
nurse an important matter is to decide what is the best food 
to substitute. Good cow's milk contains rather more fats 
than that of a woman, and much more casein; the following 
table gives averages in 1000 parts of milk: 

Woman, Cow 
280 (HO 
A : 43.0 
Milk sugur..... i 42.5 
Tnorgavic matters, 7.96 








STAGES OF LIFE. 


"The Stages of Life. Starting from the ovam each human 
being, apart from accident or disease, rans through a life- 
eycle which terminates on the average after a course of 
from 75 to 80 years, The earliest years are marked not 
ouly by rapid growth but by differentiating growth or de- 
eelopment; then comes a more stationary period, and finally 
one of degeneration. The life of various tissues and of 
many organs is not, however, coextensive with that of the 
individual, During life all the formed elements of the 
Body are constantly being broken down and removed; 
either molecularly (t¢., bit by bit while the general size 
and form of the cell or fibre remains unaltered), or in mass, 
as when hairs and the cuticle are shed. The life of many 
organs, also, does not extend from birth to death, at least 
in a functionally active state. At the former period 
numerous bones are represented mainly by cartilage. The 
pancreas has not attained its full development; and some 
of the sense-organs seem to be in the same case; at least 
new-born infants appear to hear very imperfectly. The 
reproductive organs only attain fall development at pu- 
berty, and degenerate and lose all or much of their fanc- 
tional importance as years accumulate. Certain organs 
have even a still shorter range of physiological life; the 
thymus, for example (p. 333), attains its fullest develop- 
ment at the end of the second year and then gradually 
dwindles away, so that in the adult searcely a trace of it 
ts to be found. The milk-teeth are shed in childhood, and 
their so-called permanent successors rarely last to ripe old 


During early life the Body increases in mass, at first very 
rapidly, and then more slowly, till the full sizo is attained, 
except that girls make a sudden advance in this respect at 
puberty. Henceforth the woman’s weight (excluding cases 
of accumulation of non-working adipose tissue) remains 
about the same until the climacteric. After that there is 
often an merease of weight for several years; a man’s weight 
usually slowly increases until forty. 

As old age comes on a general decline sets in, the rib 
cartilages become calcified, and lime alts are laid down 








THE HUMAN CODY. 





im the arterial walls. which thus lose their elasticit 












refracting media vf the eve become more or less opaque: 
the physiological irritability of the sénse-organs in general 
diminishes; and fatty degeneration, diminishing their work- 


ing power, oceurs m many tissues. In the brain we find 
signs of less plasticity: the youth in whom few lines of 
least resistance have been firmly established is ready to 
-vept novelties and form new associations of ideas; but 
tae longer he lives. the more difficult does this become tu 
ium. A man 7 middle life may do good, or even Ins 
lest work, but almost invariably in some line of thought 
which he has already accepted: it is extremely rare for an 
old man to take up a new study or change his views, 







































philosophic entific. or other. Hence, as we live, we 
all tend to lag behind the rising generation. 
Death. After the prime of life the tissues dwindle (or 


tthe most important ones) as they increased in child- 
> it is conceivable that, without death. this process 
nt occur nutil the Body was reduced to its original 
ne dimensions, 
ny great diminution takes place. however. 4 
own occurs sumewhere, the enfeebled community of 
forming the man 1s unable to meet the 
+ of Rife, and death supervenes. “It is as 
as te be born,” Bacon wrote long since: 
I know it few realize the fact until the sum- 
the popular imagination the prospect of 
iated with thoughts of extreme sufferin, 
sonitving life people picture a forcible and agonizing 
san entity, from the bodily frame with 
ed, Asa matter of fact. death is prob- 
with any immediate suffering. The 
sensibilities daily dulled as the end approaches: the 
nervous Ussnes, with the rest, lose their functional capacit 
and, before the heurt ceases to beat, the individual haz 
commonly Jost consciousness. 
The actual moment of death 1s hard to define: that of the 
Body generaily, of the mass as a whole, may be taken to be 
the moment when the heurt makes its last heat; arterial 
















dl 


though we 








dyn isoften as 





Mens con 











ber 





sine « 
whieh it 1 
rely 








ably relate 























DEATH. 81 


pressure then falls irretrievably, the capillary circulation 
ceases, and the tissues, no longer nourished from the blood, 
gradually die, not all at one instant, but one after another, 
according as their individual respiratory or other needs are 
great or little. 

While death is the natural end of life, it is not its aim— 
we should not live to die, but live prepared to die. Life has 
its duties and its legitimate pleasures, and we better play 
our part rather by attending to the fulfilment of the one 
and the enjoyment of the other, than by concentrating a 
morbid and paralyzing attention on the inevitable, with the 
too frequent result of producing indifference to the work 
which lies at hand for each. Our organs and faculties aro 
not talents which we may justifiably leave unemployed; each 
is bound to do his best with them, and so to live that he 
may most utilize them. An active, vigorous, dutiful, un- 
selfish life is a good preparation for death; when that time, 
at which we must pass from the realm controlled by physi- 
ological laws, approaches, when the hands tremble and the 
eyes grow dim, when ‘the grasshopper shall be a burden 
and desire shall fail,” then, surely, the consciousness of 
having ‘‘quitted ns like men” i the employment of our 
faculties while they were ours to use, will be no mean conse. 
lation, 


diy" 


INDEX TO APPENDIX, 


Abortion, 25. 
Allantols, 23 
Amenorrhas, 16. 
Amnion, 23. 
Blastoderm, 21 
Breasts, 26. 

Budding, 1. 

Caul, 28. 

Cervix uteri, 10, 
Childbirth, 24. 
Climacteric, 15. 
Clitoris, 11 

Coni vaseulosi, 6. 
Corpora cavernosa, 7. 
Corpus luteum, 14. 
Corpus spongioaun:, 7. 
Death, 30, 

Decidua, 18. 

* Development of embryo, 21 
Discontinuous growth, 1 
Diseus proligerus, 12. 
Displacement of uterus, 15. 
Dysmenorrhawa, 15. 
Eyg-cell, 4. 

Embryonal disk, 21 
Embryonal vesicle, 21, 
Epiblast, 29. 


Fallopian tubo, 4. 9, 
Feeding of infants, 27 
Fertilization, 4, 17. 
Fostal appendages, 21 
Galactophorous ducts, 26 


Gemmaution, ft. 

Germinal epithelium, 11, 

Germinal spot, 12. 

Germinal vesicle, 12, 

Gland, mammary, 26. 

Graafian follicles, 11. 

Hermaphroditi«m, 4. 

Hernia, inguinal, 5. 

Histology of ovary, 11; of testis, 
8. 

Hydrooele, 

Hygiene of menstruation, 15+ of 
pregnancy, 19, 

ilymen, 11. 

Hypoblast, 22, 

Impregnation, 17. 

Inguinal hernia, 5. 

Intra uterine development, 24. 

Totra-uterine nutrition of embryo, 
mM. 

Lactation, 26. 

Lochia, 24. 

Mammary gland, 20, 

Membrana granulosa, 12 

Menstruation, 14. 

Mesoblast, 22, 

Milk, 

Nervi erigentes, 7. 

Notochord, 29 

Organs of reproduction, 4 

4, 8. 

Oriduct, 4, 9. 

Ovulation, 14, 

Ovum, 4, 12, 





INDEX TO APPENDIX. 


Reproduction in geaeral, 
Reproductive onzans, accessory, 
4; male, 4; female, 8, 
Rupture, 5. 
Seminal fluid, & 
Semin{ferous tubules, 5. 
‘Sexual reproduction, 3. 
Somatopleure, 23. 
Spermatozoon, 4, 8. 
Sperm-cell, 4. 
Splanchnopleure, 22. 





Stages of life, 29, 
‘Testes, 4, 8. 

‘Tunica vaginalis, 4 
Umbilical cord, 28. 
Urethra, 7. 

Uterus, 4, 9. 

Utricle, 7. 

Vagina, 10. 

Vas deferens, 6, 

Vasa recta, 6, 

Vass efferentia, 6. 
Vesicule seminales, 6. 
Vitelline membrane, 12. 
Vitellus, 12, 

Vulva, 10, 

Yelk, 12. 

Yelk-snc, 22. 

Zona pellucida, 12 











—_— ieee 






Landois-Rosemann 


Lehrbuch 
ier ‘ 
hysiologie 
uflage 1. Band 


URBAN & SCHWARZENBERG 








L. Landois’ 
Lehrbuch 
Physiologie des Mens 


besonderer Beriicksichtigung der praktischen Med: 


Vierzehnte Auflage, 
Bearbeitet von 
Dr. R. Rosemann, 


©. 0, Profesor der Physiologie wind Direktor des liysfologischon Institute 
dor Westfaliscben Wilboliae Univoreitat eu MGnster. 


Erster Band. 


Mit 115 Abbildungen im Texte and 2 Tafeln. 





Urban & Schwarzenberg 


Berlin Wien 
N, Friedrichstrade 106) TL, Maximitiansteate 4 
1916, 


Kou 


Alle Rechte vorbehalten, 


ng von Professor Dr, Will. Stirling in Manchoster, 
London, 4. Auflage. 


inch-Amorikanivche Ausgabo. Philadelphia, 6. Auflage. 


‘Chersetzung ink Franzdeis 
on Prof. Dr. G. Moquin-Tendon in Toulouse. Paris, 


‘Chorsotzung tnx Japani¢ehe von Yamada in Tokyo, 


twang int Ttalienisohe von Dr, Ralduino Booei in Rom, 
Yorworte von Prof, Dr. Fao. Molosebott. Milano, Noma, ‘Torino. 


i ins Ruselseho yon Dr, Schaternikoff. Moskuv, 2 Aufago. 


ins Spanisehe von Dr, D. Rafoe! dol Valle y Aldabalde, 
Madeid. 


opyright, 1916, by Urban & Schwarzenberg, Berlin. 





\, Bde. 
\ale 


Vorwort. 


Tendenz und Bestimmung des Buches, 


Bei der Bearbeitung des vorliegenden kurzgefaften Lehrt 

Physiologie hat den Verfusser das Bestreben geleitet, fiir Arzte 
dierende ein Buch zu liefern, welches in héherem Mabe, als di 
meisten fibnlichen Werken der Fall ist, den Bediirfnissen d 
tischen Arztes dienen soll. 
: In dieser Beziehung ist in allen Abschnitten an die Darst 
normalen Vorgiinge eine kurze Skizze der pathologischei 
chungen angeftigt, Dies hat den Zweck, den Blick des Lernen 
yon yornherein auf das Feld seiner spiteren iiratlichen Wirks 
lenken und ihn aufmerksam zu machen, inwieweit der krankha 
eine Stérung der normalen Vorgiinge sei. 

Andrerseits wird dadurch auch dem praktischen Arzat 
legenheit geboten, das ihm in seiner Titigkeit in der Regel sch 
bald ferner liegende theoretische Gebiet aufs neue mit Leich 
rekapitulieren. Er kann hier mihelos yon den krankhaften Ersel 
welche er behandelt, auf die normalen Vorgiinge zurtickschane 
der Erkenntnis dieser neue Winke fur die richtige Auffassung 
handlang gewinnen. 

Ganz besonders hat der Verfasser yon diesem Gesichtspt 
alle jene Untersuchungsmethoden, welche auch von dem Prak 
grofem Vorteile yerwertet werden kénnen, und die in den Bie 
Physiologie in der Regel nur sehr kurz dargestellt werden, ci 
behandelt. Es soll hier nur auf die Abschnitte hingewiesen werd 


untersuchang — graphische Untersuchung des norma 
krankhaft veruinderten Herzstobes — Herztine und 
riiusche Pulslehre Venenpuls Transfusion — 





und abweichende Atmungsgeriiusche — Ventilation — 
suchung der Luft in Wohnriitumen — Sputum — Abwei 
yon den normalen Verdauungsprozessen — Diabetes 


A71Q5 


Vorwort, 


auung Fiebernder — Thermometric und Calorimetric 
— Untersuchung des Trinkwassers — Fleisch und 
arate — libermiibiger Fett- und Fleischansatz und 
ipfang — die Untersuchung des normalen Harnes 
timmung aller pathologischen Bestandteile sowie 
ikremente — Urimie, Ammoniiimie, Harnsiiuredys- 
rankhafte Stérungen der Harnretention und Harn- 
— pathologische Abweichungen der Schweif- und 
on — galvanische Durechleitang dureh die Haut — 
Heilgymnastik — pathologische Abweichungen der 
unktionen — Laryngoskopie und Rhinoskopie — 
der Stimm- und Sprachbildung — physiologische 
der Anwendung der Elektrizitit 21 Heilzwecken — 
etten und elektrische Apparate. — Bei der Besprechung 
nen Neryen und der verschiedenen Nervencentra ist 
ne Skizze der pathologischen Eracheinungen an den- 
ofligt. In bezug auf die Nervencentra ist besonders die 
Reflexe — die der Leitungen in den Centralorganen 
tmungscentrums. nebst Begrtindung der Hilfeleistung 
en — die Gruppe der Angioneurosen berticksichtigt. 
3 Gewicht ist ferner gelegt auf die physiologiseche Topo- 
Grobhirnoberfliche beim Menschen mit Riicksicht auf 
tersuchungen tiber die Lokalisation der Gehirnfunktionen. — 
g auf die Physiologie der Sinneswerkzeuge ist nach gleichem 
hren: die Refraktionsanomalien des Auges, die Brillen- 
‘phthalmoskopie, das Orthoskop, die Farbenblind- 
e praktische Bedeutung derselben, ferner die Unter- 
liber die Funktionen der tibrigen Sinnesorgane und 
unlichsten Stérungen liefern hierfiir Belege, Die Ent- 
eschichte hatnamentlich tiberall den Hemmungsbildungen, 
‘hmlichsten Formen der Mibbildungen, Rechnung getragen — 


niglichst genanen Zeithestimmung in der Entwicklang mensch- 


Darstellung war es das Bestreben des Verfassers, miglichst 
ersichtlich au sein, Weitschweifige Diskussionen sind grand- 
ieden. Dabei ist im Auferen itberall die Anordnung so ge- 
ichon durch den Druck das Wichtigere und das rein normal 
e hervortritt. Auch kann zuniichst der Anfiinger ohne Sti- 
dlogisch-physiologischen Abschnitte tibergehen; der Stadierende 
schen Semestern wird jedoch mit Vorteil von den letzteren 
et der normalen Physiologie repeticren, 

rfasser hat es ferner fiir geraten befunden, einem jeden Ab- 
Physiologie einen kurzen Abrié der geschichtlichen Ent- 


wicklung der betreffenden Disziplin anzafiigen, ebenso einen 
iiber die vergleichende Physiologie des Tierreiches. — — 
die Histologie und mikroskopische Anatomie in jedem 
eingehender beriicksichtigt, als dies in den meisten physiologis 
biichern der Fall zu sein pflegt. 

Durch den hiermit entwickelten Grundplan in der gesa 
stellung glaube ich das Erscheinen des yorliegenden Werkes re 
zu kinnen. 

Dab der entworfene Plan fiir die Darstellung kein Feblgril 
beweisen mir die vielfachen Besprechungen in den medizinisch 
von Nord- und Stiddeutsehland, Osterreich, der Schweiz, Ungarn 
Frankreich, England, Italien, Skandinayien, Amerika, die das 
Wohlwollen und Anerkennang begriiit haben. 

Ganz besonders aber hat es den Verfasser gefreut, dab anc 
Reihen der Physiologen dem Buche Beifall gezollt worden ist. 
um etwaige Bedenken derjenigen zu zerstreuen, welche vielle 
versuchten Anlehnung der Physiologie an die praktischen Zweig 
kunde die wissenschaftliche Hoheit unserer fiir die gesamte Med 
mentalen Disziplin gefiihrdet sehen kinnten, gestatte ich mir ei) 
aus einem Briefe eines unserer geistreichsten und erfahrensten 1 
hierher zu setzen. 


» Wenn jemand ein Handbuch verdffentlicht, wie dasjen 
erste Hilfte von Ihnen jetzt vorliegt, dann hat er den Dank 
der Lernenden, sondern auch des Lehrers und Forschers. Un 
Ehrgeiz darauf gerichtet ist, die drei bezeichneten Bigenschaf 
zu vereinigen, so sei Ihnen mein Dank aus vollem Herzen 
Thre pathologischen Ausfiihrungen sind in ihrer gedrangten 
meisterhaft klar, daji ich mir von Ihrem Buche die heilsamst 
und Riickwirkung auch auf klinischem Gebiete verspreche. 
Rom, 10. April 1879. Ihr ergebener Kollege Jac. Mole 


Wenn diese Worte sich erflillen sollten, wlirde ich 
schénsten Lohn meines Strebens sehen. — Mir hat in meiner ak: 
Lehrtitigkeit stets in erster Linie vorgeschwebt, dali mein 
in der griindlichen Yorbildung physiologisch denkender A 
mub. Und wenn man mir diesem meinen Ziele gegentiber das si 
gende Wort ,wir bilden Physiologen* entgegenhalten wollte. 
mich dieses von meiner Richtung als Lehrer nicht entwegen, v 
nun einmal fest glaube, um mit dem‘Altmeister Herophilus au ri 
aise elvas mp@ex, ei nat poh dott mpdiex, 

Der Verlagshandlung driingt es mich, meinen aufrichtigs 
Dank auszusprechen fiir die stets bereite Geneigtheit, allen Wi 
die schine Ausstattung des Buches in ausgiebigster Weise ; 


Vorwort. 


ne Anzahl Abbildungen sind den Werken yon Dr. Klein tiber 
inde; Dr. Ultsmann tiber Hiimatarie; Prof. Schnifz/ler tiber Lea- 
1; Prof. Albert tiber Chirurgie; Scheff ber Zabnheilkunde; 
sch tiber Ohrenheilkunde; Lichhorst tiber Pathologie und The- 
nk tiber Histologie; ». Jaksch tiber medizinische Diagnostik, die 
t Verlage der Herren Urban & Schwarzenberg erschienen 
mmen worden, Die Holzschnitte zum ,Harn‘ sind teil- 
vAtlas der Harnsedimente von Ul/tzmann und Hofmann 


lie Herstellung der Holzschnitte nach den yon mir selbst ent- 
‘ichnungen sage ich dem Herrn F. X. Matoloni in Wien, dessen 
+ Leistungen ich hiermit tffentlich als mustergtiltig bezeichnen 
no besten Dank, 


‘swald, den 10. November 1879. 


L. Landois. 


Vorwort zur elften Auflage. 


Als nach dem Tode Landois’ die Verlagsbuchhandlung 4 
rung an mich richtete, die neue Auflage des Landoisschen 
der Physiologie zu bearbeiten, war es fiir mich ebenso sehr 
der Dankbarkeit gegen meinen von mir hochverehrten Lehr 
Frende an einer grofen Aufgabe, die mich bestimmte, dieser 4 
Folge zu leisten. Hiitte es sich daram gehandelt, etwa ein new 
der Physiologie zu verfassen, so hiitte ich meine Kriifte und 
kaum fiir ausreichend angesehen, um eine derartige Aufgabe zu { 
Fiir die Bearbeitung des Landoissechen Lehrbuches aber durt 
zum mindesten aus dem Grunde fiir gecignet halten, weil Lan 
langen Jahren, in denen ich sein Assistent war, hiiufig mit 
Buch gesprochen und auch in der letzten Zeit mehrfach me 
liber etwa erwiinschte Anderungen des Buches eingefordert | 
sichtigt hatte. So glaubte ich, daf es mir am ehesten gelingen 
Werk in dem Sinne seines Autors weiterzutiihren. 

Ich habe aber auch von Anfang an die Schwierigkeiten ¢ 
ibernommenen Aufgabe nicht untersehiitzt; wie gro® dieselben 4 
ich ganz allerdings erst im Laufe der Bearbeitung erfahret 
Arbeit, die ich aufgewandt habe, bin ich doch weit entfer: 
glauben, dab es mir gelungen sein kinnte, dieser Schwierigk 
yollig Herr zu werden zur Zufriedenheit aller, denen das Lando, 
buch wertvoll geworden ist. Fite jeden Rat nach dieser Richtun 
ich stets aufrichtig dankbar sein. 

Die ganze Anlage des Buches ist selbstverstiindlich dieselb 
wie Landois sie getroffen hat; sie hat sich in den zahlreiche 
und der weiten Verbreitung des Buches nicht nur in Deutschla 
auch im Auslande als richtig erwiesen. Es war der wohl berecht! 
der Verlagsbuchhandlung, den Umfang des Buches, der in 
Jahren sehr zugenommen hatte, wieder etwas einzuschriinken 
daher, wo es nur angiingig schien, Kiirzungen vorgenommer 
sonders aber die Abschnitte tiber Histologie und mikroskopisel 
eingeschriinkt, Dem entsprechend lautet auch der Titel des | 


Vorwort zur elften Auflage. 


er Physiologie des Menschen ohne den auf die Histologic 
the Anatomie beztiglichen Zusatz. Ich habe mich jedoch 
a kinnen, die betreffenden Abschnitte etwa ganz fortzu- 
jrd es manchem, der in dem Buehe Auskunft sucht, er- 
renigstens die wichtigsten und fiir die Physiologie be- 
(men Tatsachen aus der Histologie und mikroskopischen 
usammengefait zu finden. 
des Buches habe ich einer griindlichen Durcharbeitung 
ihn mit dem heutigen Stande der Wissenschaft in Uber- 
bringen. Von den Landoisschen Erben war der Verlags- 
liebenswiirdigster Weise das Handexemplar Landois’ zur 
It worden, an welchem er bis kurz vor seinem Tode un- 
sitet hatte. Ich habe seine Eintragungen nach Méglichkeit 
Dbwobl der Gesamteindrack des Buches unveriindert ge- 
doch der anfinerksume Leser die vielfachen Anderangen, 
n worden sind, bemerken; nur sehr wenige Seiten des 
% unveriindert geblieben, Obwohl ich die Zeit, welehe ur- 
ie Bearbeitang in Aussicht genommen war, erheblich tiber- 
yar es mir doch nicht méglich, alle Abschnitte des Buches 
wie es mir wohl erwitinscht gewesen wiire. So sind im 
Capitel: Pathologisches, Vergleichendes, Historisches fast 
wesentliche Anderungen geblieben; ich mubte eine Bear- 
vie auch mancher anderer Abschnitte des Buches einer 
» vorbehalten. Besondere Schwierigkeiten bereiteten mir 
el, in denen Landois auf Grund seiner eigenen Unter- 
speziellen Anschauungen zam Ausdruck gebracht hat. Ich 
fiir berechtigt, hier wesentliche Anderungen yorzunehmen, 
ig, dab Landois selbst, wenn es ihm noch beschieden ge- 
se Auflage seines Buches herauszugeben, diese Abschnitte 
rt gelassen hiitte. Ich habe etwa abweichende Anschauungen 
t aufgenommen, so da ich hoffe, daS der Leser auch 
ides Bild unserer heutigen Anschanungen gewinnen wird. 
ist das Literaturverzeichnis, welehes ich dem Buche zuge- 
Fohlen jeglicher Literaturnachweise ist, wie mir yon 
immer wieder versichert worden ist, vielfach als ein 
doisschen Lebrbuches empfunden worden; es war dadurch 
‘in dem Buche Auskunft suchte, die Méglichkeit sehr er- 
Ife der angefiihrten Antornamen die Originalarbeiten ein- 
vies sich jedoch nicht als miglich, fir jeden im Text 
iach den entsprechenden Literaturnachweis zu geben; das 
nis hiitte dann einen Umfang angenommen, der in 
is zu dem Nutzen desselben gestanden hiitte. Ich habe 
inf beschriinkt, besonders wichtige Literaturnachweise zu 





Vorwort zur elften Auflage. 


geben, mit Hilfe deren eine weitere Orientierang leicht miglicl 
weit die Autoren schon im Texte zitiert sind, ist der Kiirze y 
‘Titel der Arbeit weggelassen worden, da aus der Erwahnung 
der Inhalt der betreffenden Abhandlung ersichtlich ist; ich 1 
auch mehrfach Arbeiten in das Literaturverzeichnis aufgenom 
im Texte nicht erwihnt wurden, aber gerade fiir die weitere Or 
wertyoll erschienen; bei diesen ist dann auch der Titel (oi 
kiirzter Form) angegeben, Ich verhehle mir keineswegs, dab di 
Versuch eines Literatarverzeichnisses viele Mingel aufweist, 
ich um Nachsicht bitte: ich hoffe aber gleichwohl, dai das V 
auch in dieser noch wenig vollkommenen Form die Brauchba 
Buches fiir viele erhdhen wird. — Das Inhaltsverzeichnis habe ic 
lich reichhaltiger gestaltet, damit es beim Nachschlagen miglicl 
leistet. 

Zu grobem Dank verpflichtet bin ich allen denen, welche mii 
abatige ihrer Arbeiten haben zugehen lassen: ich kntipfe daran 
mich auch weiterhin in gleich liebenswtirdiger Weise unterstiitzen | 
Besonderen Dank schulde ich den Herren Ziemke und Mille 
freundliche Uberlassang der Spektraltafel. — Wenn die Fachger 
eine etwaige weitere Auflage des Buches mir ihre Ratschliige z 
den lassen, mich auf Fehler oder Miingel aufmerksam machen 
wiirde ich daflir aufrichtig dankbar sein; ich verspreche die so 
Priifang und Berticksichtigung, soweit das nur immer miglich ; 

Die Verlagsbuchhandlang hat mir das weiteste Entgegenko! 
wiesen, allen meinen Wiinschen und Vorsehliigen freundlichst« 
sichtigang zuteil werden lassen und mich bei der Bearbeitung d 
in vielfacher Weise unterstiltzt. Es ist mir eine grobe Freude, de) 
buchhandlung auch an dieser Stelle dafiir meinen Dank sagen + 

Mige die neue Auflage des Lehrbuches sich der vyoraufge 
wiirdig erweisen, mige sie dem Buehe die alten Freunde erh 
neue gewinnen! 


Miinster i, W., im Mai 1905, 


R. Rosen 


Vorwort zur vierzehnten Auflage. 


vorliegende Auflage ist wiederum in allen Teilen sorgfiltig durch- 
und durch zahlreiche Nachtragungen und Anderungen mit dem 
tande des Wissens in Ubereinstimmung gebracht worden: bei den 
achweisen hat die neuere Literatur eingehende Beriicksichtigang 
Zu der bisherigen Spektraltafel nach Ziemke und Miller habe 
weite nach den Photographien der Blutspektra von Rost, Franz 
aufgenommen; Herrn Professor Dr. Rost sage ich flr die freund- 
abnis hierza auch an dieser Stelle meinen verbindlichsten Dank. 
izten Kapitel: .Physiologie der Zeugung und Entwicklung* habe 
n morphologischen Abschnitte gestrichen und mich daftir bemiiht, 
jlogischen Abschnitte dieses Kapitels etwas ausflihrlicher zu ge- 


vielen Autoren bin ich wiederum durch Ubersendung von Separat- 
irer Arbeiten in Suberst erwlinschter Weise unterstiitzt worden; 
Fachgenossen haben mir auferdem ihr Interesse an dem Buche 
ewiesen, da sie mich auf wiinschenswerte Verbesserungen und 
m aufmerksam machten. Ihnen allen sage ich hier nochmals 
(richtigen Dank und verbinde damit die Bitte, mich auch weiter- 
wselben Weise 2u fordern. — Auch der Verlagsbuchhandlung 
flr vielfiiltiges Entgegenkommen, das sie mir wie immer be- 
t, herzlichst zu danken. 


ister i. W., im November 1915. 


R. Rosemann. 














Inhalt. 


Allgemeine Einleitung. 


1. Bogriff, Aufgabe und Stelling der Physiologie 2a den verwandten Zweig 

[RE Sie a hee he ; 
i: Bite alaberlases5 a Se Gene eh ce Chay ed lal sidnenoe 
8. Krdfte. Arbeit. Lebendige Kraft. Energie... . . > 
4. Das Leben. Tier und Plane ose ee se ss 





Ubersicht ber die chemische Zusammensetzung des Organ 


Dio Fiwoifkirper (Proteinstoffe) . 
Die Foto 2. ee ee 

Dic Kohlchydrate 2... 
Stoffwechselprodukte . . . . . 
Anorganische Bostandteile . 
Literatur (§3—9). 2... 


Physiologie des Blutes, 


10. Allgemeines fiber die Bedeutung des Blutes. 6 6 6 ee 
11. Physikalische Eigenschaften des Blutes- . . 5 - . .- - {ace 
12. Die Formelemente des Blutos . . . . « 
13, Osmotischer Drack. Blektroly’ tischo Dissoziation, ‘Yolonte (Hyper: and nlf 
Permeabilitiit der Erythreyten . 2... 2-2 ee 
1M. Anflisang der roten Blutkorporchen, Hiimolyse . . 6... 0 0 2 oe 
15. Form, Grofe und Zahl der Erythrocyten versehicdener Tiere... . 
1G, Butstohung und Untergung der roten Blutkirperehen - 2. 2... 
17. Die weiBen Blutkirperchen (Leakocyten) und die Blutplittchen. . , . 
18. Pathologische Veriinderangen der roten und weiGen Blutkirperchen . . 
Literntur (§ 10-18)... oe ee vo 
19. Chemische Bostandteile der roten Blutkirperchen, Das Hamoglobin . 
YW. Sauerstoffverbindangen des Hiimoglobins: Oxyhimoglobin und Mothiim 
Spoktroskopische Untersuchung . . . 
Das Kohlenoxydhdmoglobin und die CO-Vs orgiftang. “Andere Hb-Verbinduny 
Zorlegung des Himoglobins. Hamoglobindorivate . . - - - . 6 ee ee 
Das Stroma der roton Blutkirperchen und die weifen Blutkirperchen . . 
Literatur (§ 19-23)... 2. . 
Das Blutplasma und der Fasorstort (di 
Allgemeine Firschoinungen bei der Gorinnung e 
. Wesen der Gerinnung - adn 
'. Chemische ‘Zosammensetzung los. Bintplasinas and dos Serums i, is 32) 
28. Bestimmung der einzelnen Bostundteile des Blutes . . . oe 
29. Pathologische Verinderungen der Zusainmensetzung a) Blutptxsmas. rn 
Gesamtblutes . . 2 2 0 ee ee 
Literatur (§ 24-29). 0 we ee ee 





Spnee 











‘ibrin) 
















rhemetkungen Gber die Strombowegung einer 


*hafton “der Blutgefibe | 
es Blutes im Gofiisystom 
= Technik der Pulsuntersachang 





las Sphygmogramm ~~. - - ) . ~~ . 

swing ie Piao 2” see 

whwi Dee ie wha Pa Set pp 
Das Phlebogramm . . . 2.2... © 


(satorische Eracheinungen., . . . . + . h 
— Mathoden der Messting des arteriellen Blatdruckes wee 
@ don Arterien 0 we 
+ den Capillaren und Venen, . . . . . eee 
1 der Arteria pulmonalis . . . - 6 + 
pees Bees a 3a 8) 





g in den kloinsten Gefen 
soho in den GefliBen 
des Blutes 6... 





Atembewegungen. Abdominaler Druck. 2... 0. ee 
der geweohselten Atmungsguse . . . . Weer as 
ge. Grobe der Lungunventilation. . . 
ve (Pneamatogramm). Typus der ‘Atembewegung 
wkelwirkang bei der Inspiration und Bespiation 
zelnon Atmungsmuskeln 2... 














esszeset 





Tobalt. 
Fe nnd AusdehnungegriBe des Thorax. Respiratorisehe Verech) 


7, Ratsinegheshe Alwalch eigen von den sormalea Bokatiyastsizioaha ant Tiras 
80. Tie normalen Atmangageriiusche 





yung 
83. Elgentimliche, abweichends Atembewegungen 
$4. Chomie der Atmung. Methoden der Untersuchung dea ‘respiratorischen 
wheels 26k te en 
85. Zosammensetzung und erase ar Atmospkrseon Tnft. . 
( Sigpomrast ts der Ansatmangalntt . 
Der respirator 








Tiguan aa wucilatoe: f ctinte ete 
Literatur (§ 70-96). 6. we ee 





Physiologie der Verdauung. 


97. Allgemeines fiber die Bedeutung der Vordannngsvorgingo. .. - . . « 
98. Die Mundhohle und ihre Drisen. Dio Speicheldrigen. Verlindornng der | 
bei der Tatigkeit . . 6.0 es ee Me SSS 7, : 

99. Die Innervation der Speicheldriisen. . . . 6. 2 ee ee bee 
100. Bigenschaften and Zogammensetzung des Soret . Gia ob ce 
101. Physiologische Wirkangon des Bpelshala oe aw aie, eh Pae 
102, Dio Kanbewognng (Masticatlo) . PBS ur ae ae ee oh 
103. Ban ond Katwicklang dor Zihne Ania Gye aera as et 
104. Scblingbowegung (Dogintatio) . - . - . . ss SS Bah ee As 
105. Bewegungen des Magens. Das Erbrechon .. - . 2... eee ee 
106. Darmbewogungen. Innervation der Darmbewegungen . .... . - = - 
107. Entleernng des Kotes (Exerotio faecum)..........0005 
Literatur (§97—J07) so se eee hie ee cite te ee 
108, Bau der Magensehleimbant . . 6 6 6 6 ee oes peau 
109, Der Magonsaft . . . . + ee eee a Fey Faia) GW! Bete hatte 
110, Sekrotion des Magongaftes 6. 0 ew ee ee oa 
111. Vorgang der Magenverdanung und. dle Verdanangrprodshio to Naame 
112. Ban des Pankreas, Absonderung des Se eee 
113. Der Pankreassaft . 2... Cn Sac ol iD sae 
114. Verdanende Wirkung des Pankreasanftes atts <2 Duet oh oh eT age Pn eth 
Litoratar (§108—114). 2 Fe ee ee ! 

115. ‘Bau dor Leber 2 et te ee 
116, Chemische Bostandteile der Leberzellon. - . « 
117. Die Zuckerharnruhr. Experimentelle Glykosurien 
118. Bestandteile der Galle . . . 
119, Die Absondernng und Ausschoidung der Galle Cee) 
|. Znriickanfsangong der Gallo; Erecheinungen der Gelbsucht (Ikteras; Svat 















Die Girungszersetzungen im Darm durch "Milkroorganism Di Darmgaa 
|. Vorgiinge im Dickdarme, Bildung der Faocos . . 

, Krankhafte file a dor Vordanungstitigkeiton 
|. Vergleichendes 

Historisches . 
Literatur (§ 115- 











Inhalt, 
































Physiologie der Resorption. 
quictentawer kane hs Pool 
sal Oia eisrade 5 F DDD a6 
slash i ink a hea 
Pigmpie ua Chylus. . . ec: 
‘ + oe B85. 
| = 
STipiuan eee Bae phaae aye coe 
Physiologie des Stoffwechsels. 
ontung deg Stoffwechsels - . - . . . cay sees 389 
Ubersicht der Nahrungsmittel. 
Untersuchung des Trinkwassers . * -+. 40 
erangstiitigkelt der Milehdriigen 42 
priiparate 343 
‘ 347 
348 
» 850 
852 
354 
Hungermstande . .. . : .. « 362 
rainer Floisehkost — reinor Fot-edar Kohlebydatios ue 


palo all covey 


SaaeieciaanT rene eatorrdctge 
nge und dos Gewichtos wihrend des Wachstam: 





Physiologie der Absonderung. 
wilung der Absonderungavorgiinge . 2... oe ee ee 380 


Die Absonderung des Harns. 





wh) S86 
at Bestimmung ‘Wes Harnstoffs und des "Gexamtstieta 390. 
Die Harnsiure and die Purinbasen 
quantitative Bestimmung der Harnsii 
in und Hippursiinre 
des Kiweibes,, Intarmediaro Stotwed 
sa Harne . . 1 ee eee . 
= Bernsteinsiiure, 











169, Die anorganischen Bestandteile des Harn... . 2 6 
170, Eiwotf im Harne (Albuminurie) . . 
171. Bint und Blutfarbstof im Harne (Hamat 
172. Gallenbestandtelle im Harne (Cholurie) . 
173. Zucker im Harne. . . 2. + + 
174. Sedimente im Harne. . . 2... 
175. Die Harnkonkremente . . . - . . - 
‘Literatur (§ 158—175) - 
Bereit 



















erensekretion 

178, Chongang verschiedeoner fone tents, tet Giftigkeit des B 

179. Bau und Titigkoit der Harnleiter . 0 ee ee 
180. Bau der Harnblase und der Harnrihre . . . 

181, Ansammlung, Zurfckhaltong und Entleerung dee Harns. Innervation der Bl: 

182, Vergloichendes, — Historisehes . . ae heute eed 

Lijertar (LTGS1GH) FS coe de 2s He ed eae ee 


Titigkeit der duferen Hant. 


188, Bam der Hawt) 66.5 ne ek ve se aie ow ait es wind oes 
184. Nagel und Haare 2 0.) oe ee 
185. Die Driisen der Haut . - 2 ee es 
186. Redeutung der Hant als iuGere Rodockung - : 
187. Die Hantatmung. — Die Hautsekretion. Der Hanitalg, dor Schweis . . 
188. Einflfixse auf die SchweiBabsondernng. Nerveneinfing . . . . ,. . 
189, Pathologisehe Abweichungen der Schweif- am Talgskretion 
190. Resorption der Hant. — Galvanische Durchletong 
191. Vergleichendes. — Historisches . . . 2. . 
Literatur (§ IB3—191). we ee 
192. Innere Sekretion, — Die Einigetinctiaes 
Literatur ($192) 6.22 









Physiologie der tierischen Warme. 


193. Quelle der tiorischon Wiirme . . . . . 
194. Methoden der Tomperatnrmessung : ‘Thermom 
195. Methoden der Wirmemengen-Messung: Calorimetric . 
196. Gleichwarme und wechselwarme Tiere... 
197. Temperatur-Topographie . « r 
198, Finiltisse anf die eres tler Einzelorgane . 
199, Schwankungon der mittleren Karpertemperatur . 
200, Reguliecung der Wirme . . 6... 0 5 « 
201, Warmebilang . 66s ee ee ee 
202. GroBe dee Wirmeproduktion 2. 0. oe 
203. Einwirkung verschiedener Temperaturen auf den Kirper 
204. Kinstliche Erhohung der Korpertomperatur, Postmortale 0 Temperaturtalzerang 
205. Dus Fieber. . . . + 
206. Kinstlicho Horabsatzung dor’ Korperamperatar 
207. Historisches. — Vergleichondes . .. . - - 
Literatur (§ 193-207)... . 0. . 

















ss Archiv f. klinisohe 


ortation, 
medizinische Woehen- 


a Physiologie et de 


e ent. Medicine, 
met, flr Ana 
ig. 
ysiology, 
pcos Chemie. 


MU, = Moleschotts Un : 
itersuchnngen zur 


Nene 


slologie, 
‘PLR. S. = Proceedings of the Royal Soci 
P. 5. = Philosophische Studien von W 
PT. ios] ‘Transact 


liche Klasse, 
‘Th, M. = Therapeutische Monatshefte. a 
V.A. = Virchows Archiv fur pathologisehe 
Anatomic und Physiologie and klinische: 





Sitzungsberichte der ikaliseh 
he _ modisalschen eat aris 


veda 
4%, a. Ch. = Zeitechrift f, analytische Chemie, 
'P, = Zeitschrift firnllgemeine Physiologie. 
Zeitschrift fir Biologie. 
Zeitschrift fiir experimentetle 
und Therapie. 
o 3s i Zeitschrift fir klinische Medizin. 
itschrift fir Ohrenheilkande, 
z, _ Ch, = Zeitschrift fir physiologische 


Chemie, 
: Zoltschritt fir physikalische 
Zeitschrift flr Psychologie und 


"Physiologie der Sinnesorgane. 
Z.x.M. = Zeitschrift fir rationelle Medizin, 





1. Begriff, Aufgabe und Stellung der Physiolo 
zu den yerwandten Zweigen der Naturkunde, 


Die Physiologie ist die Wissenschaft von den | 
scheinungen der Organismen, oder schlechtweg: die L 
Leben. — Der Einteilung der Geschipfe entsprechend untersch 
Tierphysiologie, Pflanzenphysiologie und die Physio 
niedersten Lebewesen, welche auf ae Grenze von Tier 1 
stehen, der sogenannten Protisten, und der mit ihnen auf gh 
stehenden Elementarorganismen oder Zellen, 

Aufgabe der Physiologie ist es, die Erseheinungen ( 
festzustellen, ihre Gesetzmibigkeit und Ursachen zu b 
und sie auf die allgemeinen Grundgesetze der Naturh 
mentlich auf die der Physik und Chemie zurtickzuftihren. 

Die Stellung der Physiologie zu den verwandten Zweigen 
kunde ergibt sich aus nachfolgendem Schema. 


Biologie, 


die Wissenschaft von den organisiorten Wesen, don Geschi 
(Tiere, Pflanzen, Protiston and Elementarorganismen.) 


eee "ea 


|. Morphologie: . Physiologie: 
Dio Lehre von der Gestaltung der Die Lehre yon den Leben 
Goschipfe. nungen der Geschi 
Allgemeine Spozielle Allgemeine s 
Morphologie, Morphologie, Physiologie, Phy 
Lehre you den Lebre yon don Lehre von den y 
goformtgn Teilen und Lobens Vorr 
Grund- Organen der orschoinungen 
bostandteilen Gesehiipte im Bim 
dor Geschipfo (Orgunologie, allgemeinen: a) der 
(Histologio): Anatomie): =) der Pflanzen, b) dee 
a) Histologie der a) Phytotomie, b) der Tiere. 
Pflanzen, b) Zootomia. 


b) Histologic der Tiere. 
Landois-Rosemann, Physiologic, 14, Aut. 


Die Materie, tse] 


Mil, Embryologies 
re yon der Zengung and Entwicklung der Gosehtipfe, 
1, Entwickinngsgeschichte des Kingel 


wesens, des Individunms von seinem 
Keime an, -Keimesgeschichte* 





(Ontogonie): cite 
; ysiologi- 
3 yi scher Teil der 


Babwlchongnicirt 
|. i, die Lehre von 
2, Entwieklangegeschichte ganzer der Titigkeit 


Bthams von Geeoht pte von den witrend dor Ent 
an, -Stammesgeschichte* (Phy- wicklang. 

logenio): 

a) im Planzenreicho, 

b) im ‘TMerreicho. 
yhologie und Physiologie sind gleichgeordnete 
‘ben biologischen Wissenschaft. Flir das Verstiindnis der 
ird indes die Kenntnis der Morphologie vorausge- 
dann die Leistang eines Organes richtig erfalit wy 
sen tinbere Gestaltung und inneres Geftige zuvor erkannt 
Anngsgeschichte nimmt eine Mittelstellung zwischen 
nd Physiologie ein: sie ist eine morphologische Dis- 
die Beschreibung der Teile des sich Entwickelnden 
\ sie ist eine physiologische Disziplin, soweit sie die 
id Lebenserscheinungen im Entwicklungslaufe der Ge- 
k 


2. Die Materie. 


sinnlich wahrnehmbare Welt mit Einschlué der lebenden 
us der Materie, d.h. aus dem Stoffe, der Snbstanz, die 
\t. Wir unterscheiden ponderable Materie (im gewohn- 
rauch oft schlechtweg Stoff genannt), welche auf die Wage 
ionderable Materie, die nicht anf die Wage driickt, oder 


nderablen Materie, den Kérpern, nehmen wir die Form 
ahr, d_ i. die Beschaffenheit der Begrenzung, — ferner das 
Jie Gréfe des von einem Kirper eingenommenen Raumes, 
am Aggregatzustand, welcher fest, fltissig oder gas- 


erfiillt die Riiume des Universums, jedenfalls sicher bis 
sten sichtbaren Gestirnen, Er ist der Triiger des Lichtes, 
1 seine Sehwingungen mit unvorstellbarer Geschwindigkeit 
+ in 1 Sekunde) zu unseren Sehwerkzeugen leitet. Der 
gt die vorhandenen Zwischenriiume der kleinsten Teilchen 
Materie. 
‘uns die ponderable Materie fort und fort in stets kleinere 
so wiirden wir bei fortschreitender Zerlegung zaniichst 
ofen, an denen der Aggregatzustand noch erkenn- 
ennen wir Partikeln. Die Partikeln des Eisens wiirden 
als fest, die des Wassers noch als tropfbar fitissig, die des 
1 als gasfirmig erkennen. 


[62] Die Materie. 


Denken wir uns den Teil rozeli an den Partikeln 
gefithrt, so gelangen wir endlich bis zu einer Grenze, iiber die 
weitere Spaltang weder durch mechanisehe noch auch durch 
sikalische Mittel ausgefithrt werden kann, Wir dringen vor 
Molekiilen. Ein Molekiil ist demnach die geringste M 
Kérpers, welche im freien Zustande noch existieren ki 
ferner in der Einheit nicht mehr den Aggregatzustand 2 

Die Molektile sind noch nicht die letzten Kinheiten der K 
mehr besteht jedes Molektil aus ciner Gruppe kleinster Einhe 
wir Atome nennen. Ein Atom fiir sich kann im freien Zu) 
vorkommen, vielmehr vereinigen sich die Atome mit mater 
oder verschiedenen Atomen zu Atomkomplexen, die wir Molek 
haben. Den Atomen kommt unbedingte Unteilbarkeit zu, dali 
Benennung. Wir denken uns ferner die Atome von konstanter 
an sich fest. Vom chemischen Gesichtspunkte aus ist das . 
Elementes die geringste Menge desselben, welche in 
mische Verbindung einzutreten vermag. — So wie die 
Materie als ihre letzten Teilchen die ponderablen Atome i 
so setzt sich auch der Ather, die imponderable Materie, a 
Kleinsten Teilchen, den Atheratomen zusammen, 

Innerhalb der ponderablen Materie sind nun die ponders 
mit den Atheratomen in ganz bestimmten Verhiiltnissen zue 
geordnet. Die ponderablen Atome ziehen sich gegenseitig a 
derablen Atome ziehen gleichfalls die imponderablen Atheraton 
die Atheratome stofen sich untereinander ab. So kommt es, 
ponderablen Materie um jedes ponderable Atom sich Atherat 

ern. Die ponderablen Atome streben yermige ihrer gegen 
zie) lak ar eh zueinander hin, aber nur so weit, als die Abstobi 
lagernden Atheratome es zugibt. So kénnen die ponderablen Ati 
ohne Zwischenriiume sich zusammenlagern, sondern die ganze 
als locker gedacht werden, eben durch die azwischengelage 
atome, welche jedem unmittelbaren Kontakte der ponderablen A 
streben, 

Von der gegenseitigen Anordnung der Molektile hin, 
Aggregatzustand der Kirper ab. 

Die festen Kérper haben ein eigenes nicht leicht ve 
Volumen und cigene Form, in weitem Mae unabhiingig y 
gebung. In den festen Kérpern sind die Molektile in bestim 
leicht veriinderlicher Lage zueinander angeordnet. 

Die tropfbhar fltissigen Kérper haben ebenfalls ein eig 
leicht veriinderliches Volumen, aber keine eigene Form, 
vielmehr yon der Umgebung bestimmt. In den filissigen Kirpr 
sich die Molekiile in einer steten Bewegung, ihnlich wie in ei 
wimmelnder Wiirmer oder Kiifer die einzelnen Tiere unabliissi, 
aueinander wechseln, 

Die gasférmigen Kérper haben weder ein eigenes 
noch eine eigene Form; sie fillen jeden ihnen dargebotene: 
beliebiger Form gleichmibig aus. In den gasftrmigen Kirp 
Bewegung der Molektile so grofe Exkursionen angenommen, d 
einanderstieben, uhnlich wie der wimmelnde Haufen kleine 
einem aufgelésten Schwarme auseinanderfliegt. 


Kerlifte, Arbeit. (88. . 


3. Kriifte. Arbeit. Lebendige Kraft. Energie. 


e Erscheinungen haften an der Materie. Wenn wir an der Ma- 
md eine Veriinderung, einen Vorgang beobachten, so verlangen 
1 einer Ursache, welche den Vorgang bewirkt; diese Ursache 
vir Kraft. Die Erscheinungen sind also der wahrnehmbare Aus- 
r anf die Materie wirkenden Kriifte. Die Kriifte selbst sind nicht 
nbar, sie sind die Ursache der oral i 
ier Kirper beharrt, so lange keine Kraft auf ihn einwirkt, 

o augenblicklichen Bewegungszustande (Gesetz der Triigheit): 

in Ruhe, wenn er sich in Ruhe befindet (Geschwindigkeit = 0), 

| seine Geschwindigkeit unveriindert bei, wenn er sich in Bewe- 
indet, Wirkt eine Kraft wijhrend einer gewissen Zeit auf einen 

tin (auf den keine anderen Kriifte einwirken), so iindert sich der 
gszustand des Kirpers: er bekommt eine gewisse Geschwindigkeit, 

sich vorher in Ruhe befand, oder er tindert seine Geschwindigkeit, 

sich bereits in Bewegung befand. Die Anderung der Geschwindigkeit 
siteinheit nennt man die Beschleunigung; sie ist positiv, wenn 
hwindigkeit des Kérpers zugenommen hat (von 0 = Ruhe, oder 

t bestimmten Geschwindigkeit aus), negativ, wenn die Geschwin- 

les Kérpers abgenommen hat. Das Mab der Kraft P ist das 

aus der Masse M und der Beschleunigung 9; also P=M.9. 

lem sogenannten Zontimeter-Gramm-Sekanden-MaSsystem (0, G, S-Mab- 

t die Finhelt der Linge das Zentimoter, die Finhoit der Masse das Gramm, die 

r Zeit die Sekande. Kinhelt der Kraft ist dannch diejenige Kraft, welche der 
sinem Gramm whhrend ciner Sekundo die Reschleunigung em pro Sekunde 

fe Einheit der Kraft wird 1 Dyne genannt. 

Schwerkraft an der Oberilicho der Erde erteilt einem Korper in einer Sekonde 
‘onigang g=9,80 m; dio anf einen Kirper yon der Masse M an der Oberfliche 
virkende Kraft ist also = Die Kraft, mit weleher ein Korper von der Erde 

wird, bezolohnet man als das Gewieht des Kirpers, dassolbe ist also ebenfalls = M. &- 

0. G. S.-MaBsystom ist die Kraft, mit dor oin Kérpor von der Masse 1g von 
ingozogen wird (Beschlounigung ¢=9,80 m—=980em) = 980 Dynen. 

frei fallonder Kirper orlangt unter dem Finfiu8 der Schwerkraft nach 1 Sekunde 
‘indigkeit ¢=9,80m, nach tSekunden die Geschwindigkelt v=t.g, die Ge- 

sit ist also proportional der verilossonen Zeit. Die znrickgologte Strocke, der j 
=§e ist also proportional dom Qnadrat der Zeit. Aus den beiden Gloichungen 


— vw 
\2e= unds =" 





mn eine Kraft ihren Angriffspunkt unter Cberwindung einer 
mgesetzt gerichteten Kraft oder tiberhaupt eines Wider- 
lings eines bestimmten Weges verschoben hat, so hat 
sit geleistet; die GréBe der Arbeit wird bestimmt durch das 
aus der Linge des zuriickgelegten Weges s und der Gréfe der 
also A=P.s. Als Arbeitseinheit gilt die Arbeit, welche nétig 
t kg einen Meter hoch zu heben; diese Arbeitseinheit heift Kilo- 
ster. 

0..G,S.Mulsystem gilt als Arbeitseinheit diejenige Arbeit, welche zur Uber 
st Kraft von 1 Dyne lings 1 cm nitig ist; diese Kinheit heift 1 Erg. Fir grifere 
mt man als Einheit nicht die Dyne, sondern cine Kraft, welche 1 kg pro Sekunde 
sanigung 1 m erteilt; sie ist = 100 000 = 10° Dynen; dio Arbeit, welche zur Cber- 
Vesa Kraft Kings 1m notig ist, heift 1 Jonle=10" Erg. 1 Kilogrammeter 
oule. 

rkt eine Kraft auf einen Kérper ein, ohne dabei eine andere 
er einen anderen Widerstand zu tberwinden als den, welchen 





[83] Labendige Kraft, Enorgie. 


der Kérper infolge seiner ‘Triigheit einer Anderung seines 
zustandes setzt, so erlangt der Kérper unter der ae 
’ 


Korpers = igut 
ist nach Zariicklegung des Weges s die Geschwindigkeit des 
v=|/2ps; mithin 
vi=2os 
Mv'=2Mos; und da Mo=P, so folgt 
Mv? 
SPs. 


2 
Der Ausdruck xe wird als .lebendige Kraft® bea 
Ausdruck Ps bezeichnete die Arbeit der Kraft P lings des W 
Die Fihigkeit, Arbeit zu leisten, nennt man En 
Kérpersystem kann Energie besitzen entweder infolge der 
Teile: Energie der Lage, potentielle Energie, Spannkra 
folge seiner Bewegung. seiner lebendigen Kraft: Energie 
gung, kinetische Energie. Potentielle Energie enthilt z. B. ei 
Last infolge ihrer Lage zum Mittelpunkt der Erde: stiirzt si 
Hohe herunter, so vermag sie Arbeit zu leisten. Potentielle | 
hiilt eine gespannte Feder: bei ihrer Entspannung vermag sit 
leisten (daher der Name Spannkraft, der zuweilen fiir potenti 
fiberhaupt gebraucht wird), Kinetisehe Energie enthilt jede ir 
befindliche Masse, so z. B. die von einer gewissen Hoihe he 
Last, die mit einer bestimmten Geschwindigkeit unten ankomr 
spiel der von einer gewissen Hhe herabfallenden Last zeigt 
gang von potentieller in kinetische Energie: die oben rahendi 
hilt potentielle Energie, der Betrag dareelben ist gleich der Ar 
forderlich war, die Last auf die Héhe zu heben, also=P.s. 
mit einer gewissen Geschwindigkeit ankommende Last enthil} 
Energie, der Betrag derselben ist gleich der lebendigen Kraft d 


ba Nach der oben angegebenen Gleichun; 





Masse, also gleich 


beiden Werte gleich: die potentielle Energie der oben ruhend 
also ganz libergefihrt in die kinetische Energie der unten m 
wissen Geschwindigkeit ankommenden Last. 

Kin Beispiel fiir die abwechselnde Umwandiang potentioller Rnengi 
und umgekehrt Hefert dio Pandelbewogang, Dic in dem hichsten Ponkte d 
eich betindende Pondeltinse, welche bier fir einen Momont in absotuter 
worden kann, enthalt (wie die gehobene Last des obigen Reispiels) potontiell 
der Schwingung des Vondels getzt sich diese in kinotische Energic um; we 
mit groBter Geschwindigkeit durch die Vertikule geht, ist alle potentielle 
Energie umgewandelt. Steigt unnmebr das Pendel wieder in die Hohe, so ° 
nyhme der Geschwindigkeit die kinctisohe Energie wieder in potenticlle um 
Ohne die Kinwirkung der Widerstinde (Lnftwiderstand. Reibung) whrde diesi 
Energicform sich andanernd wiederholen, 

Wenn sich in einem Systeme die einzelnen ‘Teile de 
Gleichgewichtslage nithern, so nimmt in dem System die kineti: 
auf Kosten der potentiellen zu; wenn sich die einzelnen Tei 
Gleichgewichtslage entfernen, so nimmt-umgekehrt die potenti 
auf Kosten der kinetischen zu. 

Die Umwandlung der einen Energieform in die ander 
quantitativ nach bestimmten Verhaltnissen vor sich; 1 


von dor Exbatinng der Energis. WWirme. Chemische Spannkraft. ga]. 


oder ee Energie verloren. In einem Systeme, 
sien Kine eee bleibt daher bei allen Dim- 
f innerhalb desselben der gesamte Energieinhalt 
gro6: Gesetz von der Erhaltung der Energie (Julius 
‘er, 1842; Hermann ve, Helmholtz, 1847). — Dieses Gesetz 
fir die unbelebte Natur, sondern’ ebenso auch fiir die be- 


ondere Form kinetischer Energie ist die Wirme; hierbei 
h nicht um Selena pa von Massen, sondern um eine Bewe- 
bese acne irper, der Molekile und Atome. Hiiufig 

in Warme umgesetzt. Wenn z. B. eine Last, von 

t Hohe herabstiirzend, unten mit einer bestimmten Geschwin- 


8! 
- Umgekehrt wird in der Dampfmaschine die darch die Ver- 
Steinkoblen entstandene Wiirme umgesetzt in die mechanische 
' Kolbenstange. 
ge der Warme wird gemessen nach Wirmeeinheiten oder 
iejenige Wiirmemenge, welche Lkg Wasser um 1° erwirmt. 
Jalorie (Cal), diejenige Wirmemenge, welche 1g Wasser 
at, heift kleine Calorie (cal). Eine groBe Calorie ist 
15,5 hye ag ckantachse Wirmedquivalent): d. hb dic 
menge, welche Lhy Wasser um 1° erwiirmt, vermag, in 
ein Gewicht von 425,549 1m empor- 

* ein Gewicht von 425,549 wiirde von einer Hobe von lw 
md, beim Aufschlagen soviel Wiirme erzengen, dab dadurch 
m 1° erwiirmt werden wiirde. 
sondere Form potentieller Energie ist die oT 
Zwisehen den Atomen chemisch verschiedener Stoffe 
Affinititskraft, welche die Atome zu den Molektilen pent 
inem chemischen Proze6 die miteinander verbundenen Atome 
etrennt, chemische Affinitiiten gelist, so wird Wiirme ver- 
htiger riickt: Warme wird in chemische Spann- 
tat. Wenn umgekehrt getrennte Atome sich mm Molekiilen 
w Atome, die in einem grofen Molekil infolge ihrer Lagerang 
1 Affinitdt nicht haben folgen konnen, beim Zausammenbrechen 
sich za den einfachsten Verbindungen zusammenfiigen, so 
frei: Die chemische Spannkraft wird in Wirme um- 
wie die Warme Energie der Bewegung ist, aber nicht 
Bewegung der Massen, sondern der Bewegung der 
eilehen der Kirper, so ist die chemische Spannkraft 
Lage, aber nicht Enengie der Lage der Massen, sondern 
r kleinsten Teilchen der Korper. 
aische Spannkraft wird gemessen, indem man sie in Winme 
die entstandene Wirme nach Calorien mift. 


($4) Das Leben, Tier ond Pilanze, 


4. Das Leben. Tier und Pflanze. 


Von den Vorgiingen in der unbelebten Natur schein 
ersten Blick die Vorgiinge in der belebten Natur prinzipiell 
zu sein, eine Reihe von Erscheinungen, wie Wachstum, For 
Eigenbewegung, Empfindung usw., die wir an den belebten W 
achten, kommen in der unbelebten Natur nicht vor. Diese Ers 
lassen sich alle wieder zurtickfihren auf eine Gesamtheit you 
die fur die lebenden Wesen charakteristisch sind und, solange 
wiihrt, stets bei ihnen gefunden werden: die Vorgiinge des Stoft 
Die lebenden Wesen haben die Fahigkeit, den Stoff zu wechseln, 
aus ihrer Umgebung aufzunehmen, zu Bestandteilen ihres Leibes 
und wieder nach au§en abzugeben. 

Die Bedeutung dieser Vorgiinge fiir die lebenden Wes 
zweifache. Einmal wird durch den Stoffwechsel den lebenden 
Stoff zugefiihrt, den sie zam Aufbau ihres Leibes beditirfen. A 
ausgewachsenen Organismen gehen dauernd im Laufe des Le 
augrunde, die durch neue ersetzt werden milssen: das dazu 
terial mu immer wieder von nenem in der Nahrung zugefill 
Soweit dieses Material yon anderen lebenden Wesen stammt 
‘Tier- oder Pflanzenreiche), mu es erst einer weitgehenden U 
unterzogen werden, ehe es zur Aufnahme in den Kérper ¢ 
Vielfiltige Erfahrangen (§ 5, 130.3) beweisen es, dab die 
Substanzen, die die Zellen eines bestimmten Lebewesens zusan 
yor allen andern die Eiweifstoffe durch einen besonderen At 
grofen Molektils aus einfacheren Bausteinen charakterisiert sin¢ 
einzelnen Art (vielleicht sogar jedem einzelnen Individuam?) ¢ 
ist. Diese ihre Arteigentiimlichkeit halten die lebenden V 
rend ihres ganzen Lebens mit grofer Zihigkeit fest. Das in di 
eingeflihrte artfremde Material mu daher zuniichst durct 
danungs- und Resorptionsorgane soweit zerlegt werden, bis ¢ 
teristische Aufbau des Molekiils zerstirt und ein indifferent 
geschaffen ist, das nunmehr dem Kérper dargeboten werden | 
ihm baut der Organismus dann wieder das ihm zukommende } 
seinen charakteristischen Arteigentiimlichkeiten auf und verwe 
zum Aufbau seiner Kirperzellen. 

Mit dem Stoffwechsel ist aber aweitens regelmibig cin 
wechsel verbunden, der den Lebewesen die fir den Betrieb ¢ 
vorgiinge erforderliche Energie liefert. Dieser Energiewechsel 
allen lebenden Wesen, Tieren und Pflanzen im gleich 
nimlich in der Weise, daG potentielle chemische Energie kon 
sammengesetzter Stoffe umgesetzt wird in kinetische Energ) 
Unterhaltung der Lebensvorgiinge dient und in verschiedener 
auben abgegeben wird. Die Tiere nehmen in ihrer Nahr 
Wasser und Salzen, deren Bedeutung ausschlieblich stofflich 
Eiweifkérper, Pette und Kohlehydrate auf, Stoffe, die infolge 
plizierten chemischen Aufbaues reichliche chemische Spa 
chemische potentielle Energie in sich enthalten. Im tierise 
werden diese komplizierten Verbindungen in einfache gespalti 
Hilfe des eingeatmeten Sauerstofls oxydiert; die Endprodukti 
weehsels, die schlieBlich nach anben abgegeben werden, sin 
spannkraftfreie Verbindungen, wie CO,, H,O, oder doch vers 


‘Funergioevechsel, [sh] 


me Verbindungen, wie x. B. Harnstoff. Die chemissehe Spann- 

fgenommenen aha rungsstoffe wird also im Laufe des fierischen 

i frei, cat wi ungesetzt in die kinetisehe Energie, die bei 

rgiingen zutage tritt, hauptsiichlich in mechani- 

Fue und in Wiirme. Aber auch in den Pflanzen ist ein sale 
tung verlaufender Energiewechsel vorhanden. Im pflanz- 

tismus werden ebenfalls komplizierte chemische Verbindungen, 

(ohlehydrate, aber auch Fotte, und Eiweibstoffe, abgebaut und 

+ End, Medes wird CO, A a Die freiwerdende chemische 

E ous hier in derselben Weise wie im tierischen Kérper dem 
Lebensvorgiinge; eine Abgabe von kinetischer Energie in 

Virme ist vielfiiltig nachgewiesen, Allerdings wird bei einem j 

| der Pflanzen, niimlich bei allen griinen Pflanzen, dieser | 

isel verdeeckt durch einen gleichzeitig vorhandenen, aber in | 

esetzter Richtung verlaufenden Energiewechsel. Di \ 

nzen vermigen mit dem Chlorophyll ihrer Bhitter kine i 

orgie des Sonnenlichtes aufzunehmen; zugleich nehmen sie 

ummengesetzte, also spannkraftlose Verbindungen in sich 

osiinre, Wasser, einfache stickstoffhaltige Stoffe des Bodens, 

endung der kinetischen Energie des Sonnenlichtes wird ans 

achen Verbindungen der Sauerstoff abgespalten (Rednktion), 

n Pflanzen ausgeatmet wird, und es werden die kompliziert 

‘setzten spannkraftreichen Kohlehydrate, Fette und Eiweibi ne 

Synthese). Es findet hier also ein Energiewechsel in 

on kinetischer Energie zu potentieller chemischer Boergia 

aichte tberwiegt quantitatiy bei den griinen Pflanzen dieser 

wel den gleichzeitig vorhandenen, entgegengesetzt gerichteten 

ther potentieller zu kinetischer Energie; im Dunkeln aber, wo 

me von kinetischer Energie des Sonnenlichtes in Wegfall 

{ ebenso bei den chlorophyllosen Pflanzen, die tiberhaupt nicht 

ne von Sonnenlicht-Energie befithigt sind, tritt dieser letztere 

asel_ rein zutage. Die Umwandlung von potentieller 

r Energie in kinetische Energie ist also cine allen 

n gemeinsame Eigenschaft. Die hierfiir erforderliche che- 

wgie kompliziert zusammengesetzter Verbindungen mui 

chlorophyllosen Pilanzen als solche geliefert werden, die chloro- 

n Pflanzen verméigen sie sich selbst unter Verwendung der 

Energie des Sonnenlichtes zuzubereiten. Die Tiere und chloro- 

*flanzen sind daher auf die organische Substanz anderer Lebe- 

. anletzt auf die griinen Pflanzen angewiesen. In letzter In- 

in alle lebenden Wesen vom Sonnenlichte. 





ergiewechsel von chemiseber potenticller Rmergie 2 kinetischer Exergic erfolgt 
t Umwandlang kompliziert susazomengesetzter chemischer Stoffe in cinfache; 
eine solche Unwandians berbeisafiihren, ist daher gheichfalts allen lebenden 
+ whe Pflanzen, gemeinsam. Diese Umwandleng kann entweder durch eine blobe 
BL des Tranbenauckers in Milehsiare, (,H,,0,=20,H,0,) oder darch 

mit anschlieBender Oxydation erfolgen (2 B. der Milchsiare za Kohlen- 
ser, 0,0, +0, =3 OO, +3 1,0) Bize Gewinnung kinetiseber Energie durch 
Kommt sicher im Lanfe der Lebensvorginge vielfach vor, die Oxydation der Spal- 
kann acittich end riénmlich getrennt davon erfolgen; bemerbeaswert aber ist 
te Lebewesen wihrend ihres ganten Lebens anf Spaltunges allein obne 
pewiesen sind (Anexybiose, vgl $92), so 2B. die in sauerstoffireier Um~ 
en RinzeweidewGrever, 


«saa Labenskraft, Psychisehe Vorsiinge. 


Die Gewinnung chemischer Energie aus der kinetischen Energie des Sx 
erfolgt im Organismus der grinen Pflanzen durch die chemischon Vorgiinge der BR 
‘and Synthese. Die Fihigkeit xu derartigen MG rk kommt aber keineswogs 

Wrianzen allein zu, sie findet sich ebenfulls bei allen Lebewesen, #0 auch bei 
Am Kirper dee hoheren ere sind xahlreiche Umsetzungen beknnnt, die mit 
(x. B. Entstebung yon Fett ane Kohlehydraten, vel. § 152. 1) oder Synthese (x. 
des Harnstoffs aus Kohlensinre und Ammoniak, vgl. $161, Bildang yon Hippo 
Glykokoll und Benzotsinre, vgl. § 165) cinhergehen. Die hierfiir erforderliche E 
allerdings der tierische Kérper beziehen aus der chemigchon Energie sein 
durch gleichzeitig ablanfende Spaltnng und Oxydation, eine Verwentnng kinetise 
zum Zwecke der Reduktion und Synthese, wie bei den griinen Pilanzen, ist ir 
Kirper nicht beobachtet, Es gibt aber auch im Organismus der griinen Pilanzen 
die nicht unter direkter Verwendung kinetischer Energie des Sonnenlichtes erfolg 
unter Verbrauch chomischer Energie, die durch gleichzeitige Verbrennung twa 
hydraten gewonnen wird; indirokt stammt natiirlich anch diese Energie schlicBli 
Sonnenlichte. 

Die Vorgiinge des Energiewechsels in den lebende: 
vollziehen sich nach denselben quantitativen Verhiiltni: 
in der unbelebten Natur: das Gesetz von der Erhaltung d 
gie gilt in der belebten Natur ebenso wie in der unbel 

Es ist die Aufgabe der Physiologie, die Erscheinungen, w 
in der belebten Natur wahrnehmen, auf die Kriifte der unbelebi 
zurtieckznfiihren und nach den fiir diese gefundenen Gesetzen zu 
Eine sogenannte ,Lebenskraft*, welche nach einer friher 
breiteten Annahme in den belebten Wesen wirken und in die At 
der Kriifte der unbelebten Natur in ungesetzmiibiger und daher w 
licher Weise eingreifen sollte, existiert nicht. 

Wenn wir zur Zeit gleichwohl cine grofe Zahl von Lebe. 
nungen nicht auf die uns bekannten Naturknifte zurlickznfiihren 5 
so ist das einerseits dadureh bedingt, dab der sehr yerwickelte A 
kleinsten eile der lebenden Wesen den Einblick in das Zustand 
der Erscheinungen erschwert oder noch unmiglich macht, — a 
dadurch, da auch unsere Kenntnisse yon den Kriiften der v 
Nator und ihren Wirkungen noch beschriinkt sind. Wir kinn 
mit Sicherheit annchmen, daS mit fortschreitender Erkenntnis 
heit der in der belebten und unbelebten Natur wirkenden Kriif 
dentlicher sich ergeben wird, bis schlielich alle Erscheinungen 
an den lebenden Wesen wahrnehmen, ebenso als gesetamilbige A 
der Naturkriifte erkannt sind, wie die Vorgiinge in der onbelebt 

Von den sinnlich wahrnehmbaren Lebenserscheinungen sind 
trennen die psychischen (mit Bewultsein verkni Like) Vorgiin 
kdnnen nicht sinnlich wahrgenommen werden, sondern jedes In 
dem sie zukommen, wird sich derselben unmittelbar bewubt, 
Gegenstand der Naturwissenschatt nur die sinnlich wahrnehmba 
riclle) Welt ist, gehiéren die psychischen Vorgiinge als solche n 
zum Gebiet der Naturwissenschaft. Das Wesen der psychischen ” 
ihr Zustandekommen und ihre Beziehungen zur materiellen Welt 
nicht nur zur Zeit unbegreiflich, sondern werden es der Natur 4 
nach auch stets bleiben. 


Die KiweiBkirper. 185.) 


icht tiber die chemische Zusammensetzung 
des Organismus. 


A. Organische Bestandteile. 
5. Die Eiweifkérper (Proteinstoffe).'*) 


Jiweifkbrper sind die Hauptbestandteile des lebenden Proto— 
an trifft sie in fast allen tierischen und pflanzlichen Siiften und 


n. 

Eiweibkérper enthalten C,H,O,N und S; daneben kommen in 
liweiBkGrpern auch noch andere Elemente (P, Fe usw.) vor, die 
notwendigen Bestandteile des Eiweifmolekiils darstellen. Die 
che Zusammensetzung ist folgende: C 50—55, H 6,6—7,3, 
N 15—19, 8 0,3. °/,. Das Molekulargewicht? ist noch 
icherheit festgestellt; jedenfalls ist das Molekiil der Kiweifkirper 
tlich grof (ygl. $19, das Molekulargewicht des Hitmoglobins). 
sche Konstitution. ther die lange Zeit so gut wie gar nichts 
wr, ist in neuerer Zeit besonders durch die Arbeiten Hmil Kischers* 
rden. Durch Kochen mit Langen oder Siiuren sowie unter der 
£ gewisser Fermente werden die Kiweifkirper in eine Reihe yon 
rodukten zerlegt, man erhilt hierdarch Aufschlu6 tiber die in 
1 Molektil des Eiweil vorgebildeten Kerne. Diese gehéren zum 
liphatischen, zum Teil der aromatischen Reihe an, zum 
's heterocyclische Kerne. 

‘olgenden Spaltprodukte des Eiweib sind bisher isoliert worden: 


wk Ni. 

sche Kerne. 

moaminosiiuren. 

inbusische; 

1. Aminoossigsiure, Glykokoll, CH, (NH,)—COOH. 

2 @Aminopropionsiure, Alanin, OH,—CH(NA,)—OOOH. 








8, »Aminoisovaleriansiure, Valin, (PCH —CH(NH,)—COOH. 
y 
4. «Aminoisobutylessigsiure (Aminoisooapronsiure), Lencin, 
OH, y 5 y 
OLE >oH — CH, — CH (NH,) — coon. 
weibasisehe: 
1. eAminobernstoinsiure, Asparaginsaure, 
OH (NE) — COOH 


1 
OH,— OOOH, 


Zahlen yerweisen wnf dic Literaturnachweise am Schlusse des Kapitels, pag. 30. 


($5) Spaltprodakte des Kiweil, 





¢H,—cooH, 
IL Diaminosiaren. 


1. &, bapa ye es eat 
CH, (NH,) — O8,— CH, — CH(NH,) — COOH 
stots vareinigt mit dem Guanidinrest (Gauniain (HS) Oy 
als Guanidin-2-Aminovaleriansaure, Arginin, 


NI 
GUC ST oH, —oH,— CH,— CH(NH,) — COOH, 
2. & cDiaminocapronsiure, Lysin, 
|, (NH) — CH, — CH, — CH, — OH (NH,) — COOH, 
III. Monoaminooxysiiure: 
s-Amino-f-oxypropionsiure, Serin, OH, (OH)—CH(NH,)— 
IV, Schwefelhaltigo Aminosiiure 
Cystin, das Disulfid des Oysteing, Cystein ist a-Amin 
pre Ries OH, SH —GH(NH,)— COOH, Cystin hat als 
ation 
On. i foe CH(NH,) — COOH 
0H, ,8—CH(NH,)— COOK 
©. Aromatisehe Kerne, 


1. Phenyl-a-aminopropionsaure, Pheaylalanin, 
Sa ES 


% 
On 
2. p-Oxyphenyl-a-nminopropionsiiure, Tyrosin, 
0— 08, — CH(NH,) — Coon 
aN 
He “CH 
t a 
He On 
Vv 
ou 
D, Heterocyclische Kerne, 
L Pyrrol-Grnppe: 
1, a-Pyrrolidincarbonshare, Prolin, 
OH,— CH, 


i] i 
oO 08 — COOH, 
NY 
Ni 


2. y-Oxy-a-Pyrrolidincurbonsiiure, Oxy-Prolin, 
cmon) — cH, 


Oi, OR— 000K. 


= 
Nw 
11, Indol-Gruppe. 


Peihoteree ies Tryptophan, 


ue 0 ¢—0H1,— C11 NH) — 00H. 
Ho CO OOH 


%S/NZ 
CH NIE 


Peptide. Physikalisches Kigenschaften der RiweiBke€Srper. ig 


« Imidazol-Grappe. 
Imidazol-2-aminopropionsiure, Histidin, 
NH—CH 
oe 
cH 
x 


N—C—OH,—0OH(NH,)— COOH. 
@ Spaltprodukte des Kiweif sind also durchweg Aminosiuren- 
nahme des Glykokolls enthalten siimtliche Aminosiiuren, die aus 
entstehen, cin asymmetrisches C-Atom, sind also optisch aktiv, 
Verkettung der einzelnen Aminosiiuren untereinander im Eiweil- 
erfolgt. ist nicht villig bekannt; denkbar wiiren verschiedene 
keiten, die vielleicht nebeneinander yorkommen. Nachgewiesen ist 
our eine Verkettung in der Art, dab die Aminograppe der einen 
ture sich mit der Carboxylgrappe der anderen yerbindet. So ent- 
B. aus zwei Molekiilen Glykokoll (Glycin) das Glycylglyein: 
CH, (NH.)—COOH + CH,(NH,)—COOH —H,0 = 
CH, (NH) —CO 


NH—CH,—COOH, 

orartige Verbindungen, die sich aus zwei oder mehr Aminosiiuren 
ensetzen, bezeichnet [. Fischer* als Peptide und unterscheidet je 
aw Zahl der Aminosturen, die am Aufbau beteiligt sind: Di-, Tri-, 
, Penta-, Polypeptide. Das komplizierteste, bisher synthetiseh 
‘te Polypeptid ist eine 18-gliederige Kette, ein Oktadekapeptid, 
id ans 3 Molekillen Leucin und 15 Molektilen Glykokoll, Die Poly- 
stehen bereits den Peptonen nahe. Die verschiedenen Kiweibkérper 
teiden sich voneinander sowohl durch das Vorhandensein resp. 
hestimmter Kerne, als auch durch Differenzen in den quantitativen 
rissen der vorhandenen Kerne, sowie durch die verschiedene An- 
‘der Kerne im Molekiil. Selbst bei villig gleichen quantitativen 
aissen ist durch verschiedene Lagerung der einzelnen Kerne im 
des Eiweifes eine fast unendlich grofe Zahl yon Isomerien 
‘. Vielfache Beobachtungen sprechen dafiir, dab die chemisch yon- 
r nicht zu unterscheidenden Kiweibkirper verschiedener Tierarten 
ht sogar verschiedener Individuen?) derartige isomere Substanzen 
m: jede Tierart ist danach durch einen ihr eigenttimlichen Aufbau 
olekiils charakterisiert (Arteigentiimlichkeit des Eiwei6), 
ie Eiweifkirper sind meist léslich in Wasser oder verdiinnten 
ngen, dagegen unliislich in Alkohol oder Ather. Die .geliisten* 
érper betinden sich jedoch nicht in einer wahren Lisung, sondern 
sog. kolloiden Zustande: sie diffundieren (mit Ausnahme 
‘tone) schwer oder tiberhaupt nicht darch tierische Membranen, 
sind entweder gar nicht oder nur schwer zum Krystallisieren 
ren; krystallisiert sind bisher dargestellt worden Hiimoglobin, Bier~ 
ramalbumin, Vitellin, verschiedene pflanzliche Eiweibstoffe. Die 
Grper drehen die Ebene des polarisierten Lichtes, und zwar 
ach links. (Rechtsdrehung zeigen Nucleoproteide, Nucleohiston, 
pbin [Gamgee u. Croft Hill*|,) 
snktionen der KiweiBkérper. 


iwhenreaktionen: 1. Xanthoprotein-Reaktion. Mit Salpetersiiure gekocht, 
Eiwei8 golb, nach dem Obersittigen mit Ammoniak oder Natronlange orange. ie 
beruht anf der Anwesenheit aromatischer Kerne im Eiweifmolekil. — 2. Mellom- 














[s5] Reaktionon der Riweillktirper. 


sche Reaktion. peta trea hs (Mercorinitratlisung mit salpetriger Sa) 
fiirbt. sich Eiwei8 rot. Die Reaktion bernht anf der Anwesenheit einer net 
(Tyrosin) im Kiweifmolekil. — 3. Binret-Reaktion. Gelostes KiweiB gibt mil 

(ungelistes wird erst mit Natronlange gekocht nnd noch dem Erkalten untersnch 
verdiinnter Kapforsulfatlisang (tropfenweise zugesetat, ein UberschuB yerdeckt di 
violette bis rote Firbong. (Biuret, ein Derivat des Harnstoftos, gibt dioselbe Ry 
4, Adambkirwiezsche Reaktion, Dis Lisung miglichst trockenen, entfetted 
in Eisessig wird durch konzentrierte Schwefelsiiure violett Lrersti ie Wirka 
essiga beruht nach Mopkine u, Cole* nur anf dem Gebalt Glyoxy! 
‘kann daher statt dos Eisossigs auch verdinnte Glyoxylsiiare verwenden.) Die Rew 
anf der Anwesenheit des Tryptophans im Fiweifimolekil. — 5. Lieber) 
Reaktion. Lisungen von trockenem, entfetteten Kiwei8 in konzentriorter Salzs 
sich bei gew0hnlicher Temperatur nach ciniger Zeit, beim Kochen schnoller 

violett, Die Reaktion beroht nuf der gleichzeitigon Anwesenheit einer aromal 
einer Koblehydratgrappe im KiweiSmolekiil. — 6, Mofixchsche Reaktion. S 
einer FiweiBligung éinige Tropfen einer alkoholisehen Lésung von «Naphthol ) 
kongentrierte Schwaefelsinre, so entsteht eine violotte Fiirbung, bei Verwendung 

an Stelle des &Naphthols elne rote Farbung. Die Reaktion beruht auf der 
ciner Kohlehydratgrappe im Riwoifmolektl. — 7. Schwefelblei-Reaktion. B 
mit wenig Bleiacetat und tiberschtissiger Natronlauge enteteht Golb-, Braun- od 
fiirbung, eventuoll cin schwarzer Nioderschlag von Schwofolblei. Dio Reaktion 
der Anwesenheit der Oystingruppe im EiweiBmolekil, Abspaltung von Schwefe 
und Bildung yon Schwefelblei. 


Fillungsreaktionen, — Die Eiweiikirper bellnden sich in thren Lisan, 

kolloiden Zustande (s. shat Dio kolloide Losung cines Stoffes wird als Sol 
ist Wasser das Léisungsmittel, so spricht man yon Hydrosol. i peal =| 
komnon kolloide Korper ans dem Sol-Znstand ansfillen, der ausgefilllte Kirpe: 
Gel, resp, Hydrogel bexsichnet. Die Umwandlnng des Sol-Zustandes ind 2 
kane entweder irreversibel oder reversibel sein, Im ersteren Fallo hat der 
Korper so weltgehonde Verinderangen erlitten, daS er nicht wieder ohne weit 
ist, Boi don BiweiBkirpern nennt man diese irreversible Anderung ibres Zastan 
bei den meisten Ausfillungen erleiden, Donaturierung; sie werden dabei in ein 
Modifikntion Abergefthrt, koaguliert. Koagaliertes Fiweif ist avch der Entf 
Fillangsmittels nicht wieder tnveriindert Welich; es kann nor in Lisung gebri 
durch a) verdinnte Langen, wodureh Alkatialbuminat entsteht, — b) verdim 
oder starke organische Siuren, wodnreh Acidalbamin entsteht, — ¢) die Verdauar 
Albumosen ond Peptone entstehen, — Das Aussalzen der Eiweifkirper dure! 
von Noutralsalzen (aiche unten 6.) ist ogee eine reversible Zustandsiind 
Eiwoifkiirper werden dabel nicht koaguiiert; nach Entfornung des Fillungsmitt 
unyeriindert léelich, wie aavor, Die Methode des Aussalzens ist deswegen fir 
suehung der Eiweifkérpor von ganz besonderer Bedeutung. 

Fiweif filllond wirken: — 1. Erhitzen bei schwach sanrer Reaktion 
gulationstemperatur ist fiir die verschiedenen EiwalBkiirper verschieden, fur 
donselben EiweiBkirper aber auch abbingig yon der Konzentration, dem Salz 
der Reaktion der Lisung. — 2. Starker Alkohol; bel lingerer Rinwirkan, 
Kiweif in den koagolierten Zostand Qbergefbhrt. — 3. Konzentrierte Minerals: 
allem Salpetersinre, ebento Metaphosphorsure. — 4. Salze der Schw 
(Eisenchlorid, nontrales und basisches Bleincstat, Kupfersulfnt, Platinchlorid, 4 
ehlorid in salasaurer Tecan); die B die Schwermetalle ‘bilden mit dem Kiweif als Stine 
unldsticho Verbindungen, — 5, Die sogenannten Alkaloidreagentien: Essi 
Ferrocyankalinm, Gorbsinre+ Easigsiiare, Pikrinsiure+ Citrononsiure, ‘TS 
silure, Phosphorwolframsiare, Phosphormolybdinsiiure, Jodquecksilber-Jodkalinm 
yon Salzsiiare, — 6, Aufliisung yon Neutralsalzen (Sulfate des Ammoniums, 3 
Natriums, Zinks; Kochsalz) besonders bei sanrer Reaktion (Anssalxen). Gesehiel 
eosatz guns allmalich , 80 lassen sich auf diese Weise manche Biweiflkirper k 
ansseheiden, Durch ‘Aussalzen werden die Eiweifstotfe chemisch nicht yeriind 
koaguliort), sie behalten insbesondero ihre Lislichkelt. 

Quantitative Bestimmung des Eiwoif. Das BiweiS wird darch | 
schwach sanrer Reaktion ansgefillt, auf einem gewogenen Filter gesammalt, got 
gewogen, darant verbrannt und das Gewicht der Asche in Abang gobracht. 

Enthiilt die su untersuchende Flissigkeit anBer Fiwei8 keine anderen N-balti 
so kann man nach Ajeldah! den N-Gebalt bestimmen (§ 162) und durch Maltiy 
N mit 6,25 ungefihr deo KiweiBgebalt berechnen. (Eiwoif enthilt im Mittel 1 
NX 6,26=Kiwoif. Freilich ist der N-Gehalt verschiedener EiweiSstoife yerschi 


Yrivedine, Albumine and Globnlines. 






> Eiweibkirper werden eingeteilt in Proteine (Kiweifstoffe im 
Sinne, genuine oder native Eiweibstofle), — Proteide (Verbin- 
von Kiweif mit anderen Kirpern) und — Albuminoide (eiweili-— 
Korper). 

I. Proteine. 


>» Proteine — sind die Eiweifstoffe im engeren Sinne, auch ge- 
‘er native Eiweifstoffe genannt, sie sind lislich in Wasser 

en Salzlésungen und sind linksdrehend. Diese Gruppe umfaft die 
ne und Globuline. ~ 
Die Albumine — sind lslich in destilliertem Wasser, sie werden 
sfillt durch Siittigung ihrer Lésungen mit Kochsalz oder Magnesium= 
ler durch Halbsiittigung mit Ammonsulfat, dagegen werden sie 
durch Siittigang mit Ammonsulfat oder Zinksulfat. Die Albumine 
. (im Gegensatz zu den Globulinen) kein Glykokoll. "" 


das Ser umalbumin (vgl. § 27). 
dns Eieralbamin (Ovalbamin) (rgl. $143) — im Weillen der Vogeleier, von 
+ krystallisiert durgestellt, Koagulationstemperatur GO—G4°, bei Anwesenhelt von 
+ Spoaifigehe Drohung — 30,7°. 

das Lactalbumin (vgl. § 142), Koagulationstemperatur wie beim Sornmalbnmnin ; 
Drehung — 36,4 bis 37,0°. 

Das Myogen (vel. § 211), 


Die Globuline — sind unldslich in Wasser, léslich in verdiinnten 
2 neutraler Salze und in verdtinnten Alkalien, Sie werden daher 
a salzhaltigen Lisungen durch Zusatz von viel Wasser oder durch 
gefillt; au$erdem werden sie durch Siittigung ihrer Lisungen 
mesiumsulfat und darch Halbsittigang mit Ammonsulfat geféillt, 
im Gegensatz zu den Albuminen) schon durch stark verdtinnte 
sogar durch Kinleiten von CO,. 

Das Serumglobnlin (ygl. § 27). 

Ons Rierglobulin (vgl. § 143). 

Yas Milchglobulin (vgl. § 148). 

Ons Fibrinogen (vel. § 26). Unter der Finwirkung des Fibrinferments geht es 
fiber. 
Dax Fibringlobutin (vgl §26 0. 27). 
Das Myosin (vgl. § 211), 
Das Thyreoglobnlin (ygl. § 192, 1); jodhaltig. 

iwandlungsprodukte der Proteine. 1. Koagulierte Kiweibstoffe — ent- 
den gonuinen oder nativen FiwelSstotfen durch Erhitzen oder lingere Rinwirkung 
ol (vgl. S. 18). 

Fibrin — ans dem Fibrinogen durch das Fibrinferment entstehend (vgl. § 26) 
Alkali-Albuminate, — Kali und Natron (auch Atzkulk und Atzbaryt) erzeagen 
uum 30 schneller, je konzentrierter die Alkalilésing und je hoher die Temperatmr 
en Fiweifstoiten Verbindungen, welche man Alkali-Albnminate nennt. Sie 
onders starke Drehung, gerinnen nicht beim Kochen ond werden ans ihrer Lisnng 
san, die das Alkali binden, niedergeschlagen. 

Acidalbumine (Syntonine) — entstehen durch die Kinwirkung von Siinren 
insalzsiure anf EiweiSstoffe. Sie sind unlistich in Wasser ond noutralen Sale- 
Jeicht Walch in verdinnten Siuren und vordinnten Alkalion. Aus der Léistm 
darch Kintragen von viel Kochsulz oder Glanbersalz gefillt, ebenso raft New 

sh Alkali Pillang hervor, nicht hingegen Siedehitze. 

Vordanungsprodukte der Eiweifstoffe: Albumoson und Peptone 
i 

besondere Gruppen yon Kiweidstoifen sind anfznfihren die Histone, die Pro 
nd die vegetabilischen Proteine. 

Histone — sind durch ihren basischen Charakter (bedingt durch hohen Gehalt 
besonders Arginin) and hohen N-Gehalt charakterisiert. Sie finden sich im Kirper 
ang mit sauren Atomkomplexen, von denen sie durch verdinnte Siuren abgetronnt 


1894 * — Vegotabilisehe Proteine, Proteide, 


werden, so in Verbindung mit Nucloin als Nucleohiston in der Thymusdei 
Vogelerythrocyten und Leukocyten. als Globin (§ 22) yerbunden mit Hiimatin 
globin in den Krythrocyten, endlich im verschiedener Fische. 
Die Protamine — sind sehr stickstoffreiche (26—30%,), abor schwofol 
reichlich Diuminosii 


Arginin), aber wenig Monoaminosiuren, Kassel berei¢hnet sie als die einfachston Fit 
Sic kommen im Sperma vielor Fische in Verbindung mit Nueleinsinren vor. 

Vegotabilische Proteine.* — Die Pilanzen enthalten, wenngleich in 
Monge als die Tiere, Hiweifkirpor versehiedener Art. Sie treten entweder | 
(geqnollener) Form anf, numentlich in den Siiften der lebenden Pilanzen, ode 
Form. Man onterseheidet: 

1. Pflanzenalbumine — sind in den Pflanzen weit verbreitet, aber ; 
yon den begleitenden Globulinen xm trennen. Niher untersucht sind Albumine 
forner aus Weizen, Roggen und Gerste, welche als Leukoxin zusammengefaSt w 
Leukosin unterseheidet sich vom tierischen Albumin dadurch, daf es durch Sit 
Kochsalx und Magnesiamaulfat gofiillt wird. 

2. Pflanzenglobaline. — Kin Teil dieser EiweiBstoffe wurde friher 
zeneaseine bezeichnet, weil sie wie das Casein in schwachon Alkalion Joslich 
durch verdinnte Séuren und Lab gefillt werden, Hiersu gehiren: Das Legnmin 
minosen, das Glutencasein des Weizens (der in Alkohol unlisliche Teil der Kle 
stoifo), das Oonglutin der Lapinen. Fur eine Grappe aus verschiedenen Pilo 
(Weizen, Mais, Gerste, Reis naw.) horstellbarer Globaline haben Chittenden un 
den Namen Edostin cingofthrt, cine andere Gruppe (in Mais, Hafer, Bohnen) 
sie als Pflanzen-Myosine. Kin im Hafer yorkommendes Globulin wird als 
bezeichnet. 

Die meisten dieser Globuline lassen sich aus der kochsalzhaltigen Lisnng in 
(Oktaéder, Sphiroide, hexagonale Platten) gewinnen. 

8. In Alkohol lésliche Pflanzenproteine. — Diese Grappe ist in 
reiche (im Gegensats um Tierreiche) weit verbreitet. Sie finden sich reichlich in ¢ 
stoffen dex Getreides, die als Kieberproteinstoffe zusammengefabt werden, 
des Weizens tindet sich xoniichst ein in Alkohol unloslicher Kiweifstoif, das Glut: 
welches za den Globalinen gohort (8, unter 2), anBerdem aber drei vonoinander ve 
in Alkohol lusliche Stoffe: das Glutenfibrin, dag Gliadin nnd das Mnoedin. 
Gerste kommt dus Hordein vor. 





Il. Proteide. 


Die Proteide — sind Verbindungen von Proteinen mit ande: 
eiweiBartigen, meist kompliziert zusammengesetzten Kérpern, die 
»prosthetische Gruppe* bezeichnet; sie knnen durch Spaltuns 

asser, Situren oder Alkalien in ihre beiden Bestandteile zerlegt 
Nach der Art der prosthetischen Grappe unterscheidet man; 


A. Chromo-Proteide — Verbindungen yon Eiweif mit Far 


Das Hamoglobin (vgl $19, seine Verbindungen und Derivate § 20 bis 
eine Verbindung yon Hamatin pit Globin, Das Globin gebort an den 
(vgl. oben), 

B. Glyko-Proteide — Verbindungen von Kiweii mit Koblel 
oder Kohlehydratderivaten; bei der Spaltung liefern sie Glue 
(vgl. pag. 26). Kohlehydratgruppen sind aber auch in anderen 
kérpern, echten Proteinen, gefunden worden: vielleicht gehérer 
hydratgruppen tiberhaupt zu den Spaltprodukten des Eiweibes. 
wiirden also die Glykoproteide nur dieses Spaltprodukt in besonder 
Menge enthalten. 

1. Die Muoine — sind in Wasser unlislich, verilissigen sich aber in Wass 
ziehend, schloimig, Mit wenig Atkali geben sie nentrale, fadenziohende 
Sie gerinnon nicht beim Kochen, werden gefillt durch Sinren (verdiinnte Essigsiin 
Alkohol (der Alkoholniederschlag Wst sich wieder in Wasser), nieht durch Essig 
Forrocyankalinm, Sie zeigen alle Farbenreaktionen der KiweiSkirper, Sie finde 
Spoichel, in der Galle, in den Schleimdrisen und Sokreten dor Schleimbinte, in 











Proteide. Albuminoide. . 


belschnar), in den Sehnen (im ‘Terreich besonders in den Schnecken und in 4 
lolothurien). 

ie Mucoide — den Mueinen tihntich, aber im nee Verhalten 
Ktionen abweichend; 2. B, das Ovomucold im Hahnoreiweif ua. — 
incoid vgl 8. 17. 


Verbindungen yon Eiwei8 mit phosphorhaltigen Subs 


fie Nuclooproteide? — sind Verbindungen von Kiweif (moist eln Pro 

1) and Nuclei Die Nucleine sind wiedoram Verbindungen von Riwe 

insiiuron, lich li h 

Nucleinb: . 

Nucleoproteide bilden die Chromatinsubstanz der Zellkerne (daher der 

omnach im Tier- und Pilanzenreich schr verbreitet. Sie sind nur wenig lislieh 

| Silzlétungen, haben sauren Charakter und vereinigen sich ie a 

n, leicht lWelichen Verbindungen; durch Siuren werden sie gufallt. Durch 

‘erden sie gespalten in Kiweil, welches weiter za Albumosen und Peptonen 

und Nuclein, welches sich absebeidet, da es gegen Pepsinsalzsiure eine inves 

afihigkeit besitzt, Nacleoproteide sind hergestellt aus Thymosdrise, Pankreas, 

1, Leber, Gehirn, Schitddriise und anderen Organen, sowie aus geben , 

sloine sind in Wasser und verdtinnton Siuren unldalich oder nur wenig ‘ 

Wslich. Sip haben stiirker sauren Charakter als die Nuclooproteide, héheren 

und besitzen eine hohe (doch nicht absolute) Widerstandsfihigkeit gegen 

durch Trypsinverdanung werden sig gespalten. — Die Nucleinsinren geben 

instande keine KiweiSreaktionon mehr, sie enthalten ©, H, N, O und P, keinen 8. 

dlich in Wasser und Alkalien, werden durch Mineralsinren ans ihren . 

Bei der Spaltung liefern sie — 1. Phosphorsiure. — 2, Naclein- oder Pa 

(val. pag. 27), niimli iden Aminopurine: Adenin und Gnanin; derek 

irkung werden sie bei der Spaltung teilw: in die entapreehenden arine: 

thin und Xanthin umgowandelt, diose sind aber urspriinglich in dor Ni 

anden. — 3. Pyrimidinbasen (vgl. pag. 28), nimlich Thymin und Cy tosing 

(wird bei der Spaltung teilweise in i) tibergefihrt. — 4. See 

xosen nnd (?) Pentosen. — Von der cigentlichen Nucleinsinre unt 

rerhiltnismadig einfache Zasammensetsung die aus Pankreas horgestellte meres 

Iho bei dor Spaltong quantitatiy in je 1 Molekil Guanin, Pentoso und 

Nt, — und die im Floigchextrakt vorkommends Inosinsiure, welche analog 

(oloktil Hypoxanthin, Pentose und Phosphorsiure besteht, 

dio Paranucleoproteide (Nuclooalbumine) — sind ebenfalls phosphor 

cifkirper, unterschoiden sich aber yon den Nucleoproteiden dadurch, dal aie bet 
1g nobon Kiweif und Phosphorsiiure keine Nucloinbasen, Pyrimidinbasen 

thydrate liefern. Sie finden sich besondors als Bostandteile der Nahrung wack- 

anismen (Mile, Hidotter, s. u.), dagegen haben sie xu don Zellkernon gar keine 

die Bezeichnang als Paranucleoproteide oder Nucleoalbnmine ist alge 

vwehtfertigt, sie werden daher neuerdings auch einfuch als Phosphorproteide 

Sie sind Siiuren, in Wasser fast unlislich, geben aber mit Alkali Nisliche Ver 

din bel noutralor Reaktion dareh Kochen nicht gefiillt werden, dureh Zasntz you: 

‘den aus diesen Verbindangen die Paranucleoproteide wieder frei gemacht und 

i dor Einwirkung von Pepsinsalzsiure worden sio geepalten in Eiweil, welches 

lant wird, und in sich abschoidendes Paranuclein; doch wird dieses darch 

Pepsinwirkung schlieBlich auch yollig gelést (vgl. § 111). 

Jas Casein (§ 142) — findet sich an Kalk gebunden in der Milch aller Sanger; 

Stinrexusatz oder durch Lab geffillt; nicht jedoch durch Kochon. 

Yas Vitellin (§ 143) — findet sich im Eigelb; es ist durch Siittigung mit Koeh- 

fillbar, Als ,Dotterplittchan* kommen krystallisierte Vitelline vor in den 

Fische, Frischa, Schildkriten, In den Vogeloiern sind die Vitelline «morph, 

ns Nucteoalbumin der Galle (§ 118, 3). 


Ill. Albuminoide. 


: Albuminoide — stehen den echten Eiweibktrpern hinsichtlich 
sammensetzung und Abstammung nahe, doch zeigen sie in ihrem 
\sechen, chemischen und physiologischen Verhalten viele Abwei- 
yon ihnen, Sie sind unkrystallisierbar. Sie bestehen fast aus- 
h aus Monoaminosiiuren, im besonderen fehlen ihnen zum Teil 


ga) AMbnininoide, Fermonte, 


die aromatischen Gruppen, so dab sie bei der Spaltung kein 
geben. Kinige von ihnen cathalten keinen Schwefel. Sie sind Le 
daulich, teils zwar verdanlich, allein ihre Verdanungsprodukte kin 
Kiweif gar nicht oder nur anvollkommen ersetzen, weil ihnen ebe 
tige, fiir den Kirper unentbehrliche Aminosiiuren fehlen. Sie find 
wesentlich in den Stlitz- oder Schutzsubstanzen des Kirpers; in 
Weise sie aus den Eiweibkérpern entstehen; ist unbekannt. 


Keratine — bilden den Hauptbestandteil aller Horn- ond Aiea 
Sie sind unlislich in Wasser, lislich in konzentrierter Sehy ire und kochendon 
Charakteristisch ist flr sie der hohe S-Gehalt (2—5%,). Sie widerstehen d) 
und Pankreasverdaunng sowie der Faulnis. Bei der hydrolytischon liefor 
‘fyrosin und yiel Cystin. — In den a findet sich dax Neuro 
2% Elastin — Grandstoff des elastischen Gewebes, am reichsten im Li 
Tn Wasser anlislich, —_— in eee Es gibt die Reaktionen des Eiweil 
Zorscta rodukte, Von Magensaft and Pankreassaft wird os verdant, aber schwarer ; 
3. Kollagen — ist der a der Bindogewebsfasern, der Sener 
Fascien, der organischen Grundeubstanz der Knochen and Kno Mit Wasse 
geht ¢s in Glutin oder Loim fiber, welcher beim Erkalten gelatiniort. In kalte 
ist Leim nicht Wslich, sondern quillt nur darin auf; lslich in Alkulien. Dic 
werden darch Siiaren und im allgemeinen aoch durch Metallsalze nicht gefiillt. 
ist stark linksdrehend. Er wird durch Magensagt und Pankreassaft verdaut. Boi de! 
liefort der Leim kein Tyrosin (or gibt daher auch keine Millonsche Rewkti 
‘Vryptophan, kein Oystin. 

. Chondrin oder Knorpelleim — wird durch Kochen aus Knorpol: 
und gelatiniert beim Abkiihlen. Ea ist jedoch kein einheitlicher Kirper, 8¢ 
Gemenge yon Glatin und Chondromucoid (vgl. S 16). Dieses liefert bel der 
Riwei8, Koblehydrat und Chondroitinachwefelsiure, Die Po Niet 


siure ist eine Ather-Schwofelsiure des nan aealtinn Cy + digsos | 
seiner Spaltang Essigniure und Chondrosin pe med 
Glykuronsinre (,H,,0, und Glucosamin Ota) (vel 8. 26), 


5. Fibroin and Sericin (Seidenleim) — 1 ta die beiden 
Seidengospingte der Insekten und Spinnen. — Dom Fibroin mala | it das 
—— die Substans der Badoschwimmo, 

6, Dag Amyloid — nor pathologisch vorkommend, in Form geachichtoter 
(Corpora amylacen) im Gebirn und in dor Prostata, als ghinzende Infiltration « 
Milx, Nieren, GofiBhinte, kenntlich an der Bilinang durch Jod und Schwefelsiiar 
Rotang darch Jod. 


Die Fermente (Enzyme)* — werden haufig als Kiweilist 
den Eiweilstoffen nahestehende Kérper angesehen, doch lilt s 
ihre chemische Natur zur Zeit nichts Bestimmtes aussagen, da 1 
Fermente aus ihren Lisungen wohl bis zu einem gewissen Grade j 
aber nicht chemisch rein darstellen kann. Es ist gelungen, Priipa 
fermentativer Wirkung herzustellen, die keine Eiweibreaktionen 
Sicherlich besitzen die Fermente aber ein kompliziert aufgebantes 
sie enthalten alle N, die meisten auch S$ und P, in einigen ist C 
nachgewiesen worden. 

Die Fermente bewirken durch ihre Gegenwart chemische Umse 
ohne selbst an dem chemischen Prozeb teilzunehmen, nach Bet 
der Reaktion erscheint das Ferment nicht in den Umsetzungspr 
sondern ist neben diesen unyertindert vorhanden. Die Fermente 
als Katalysatoren aufgefabt, d.h. ihre Wirkung besteht nach di 
schauung darin, dab sie chemische Prozesse, die auch yon sell 
dann mit auberordentlich geringer, unmebbarer Geschwindigkeit 
wiirden, so beschleunigen, dab sie in mefbarer Zeit ihr Ende e 
Die Wirkung der Fermente ist streng spezifiseh, d. h, ein jedes 
wirkt immer nur auf bestimmte Vertreter einer bestimmten Kér 
ein, und ‘ist anderen Substanzen gegentiber durchaus wirkungs 


Landols-Rosemann, Physiologio. 14, Aud. 


Fermente, 


+ der strengen Spezifittit der Fermentwirkung awingt zu dex An- 
daS awischen dem Ferment und scinem Substrat eine bestimmte 
1g bestehen muf, die in dem Aufbau der beiderseitigen Molektile 
ist: Ferment und Substrat mtissen zu einander passen wie der 
1 zum Sehlob. - 
© Fermente sind meistens (cine Ausnahme bilden gewisse Lipasen) 
o Wasser und Glycerin und kinnen durch diese Li 

Geweben extrahiert werden. Doch handelt es sich dabei nicht um 
ondern um kolloidale Lésungen, wie bei den Eiweibki 

13). Aus der Lésung werden sie durch Neutralsalze (z. B. Ammo- 
‘at) bei bestimmter Konzentration ausgesalzen wie die Eiweibktrper 
13), auch durch Alkohol werden sie gefillt, Sie diffundieren nicht 
ch nur sehwer; die Fihigkeit zu diffundieren ist bei den einzelnen 
en verschieden und hiingt auch von der Art der angewandten 

a ab. Kérpern mit grofer Oberfliiche, voluminisen Nioterectitea 
ie Fermente fest an, sie werden von ihnen adsorbiert; 

Fibrin ist in dieser Bezichung sehr wirksam. 

e Wirkung der Fermente kann durch viele Momente beeinfluiit 
Fiir jedes Ferment gibt es ein Temperaturoptimum und eine Tem- 
renze seiner Wirkung, oberhalb dieser Grenze hért die Wirkang 
ments auf und bei noch hherer Temperatur wird das Ferment 
Doch gilt dies nur fiir die wiisserigen Lisungen der Fermente, im 

m Zustand vertragen dic Fermente Erhitzen auf 100° und sorar 
riiber hinaus. Gegen niedere Temperaturen (—190°) sind die F 
uberordentlich widerstandsfihig. 


ahrscheinlich werden alle Fermente yon den Driisen zuniichst in 
inwirksamen Zustand als sog. Profermente oder Zymogene 
tieden, diese miissen erst in den wirksamen Zustand tibergefiihrt oder 
rt werden durch die sog. Kinasen (vgl. Thrombokinase § 26, 
inase § 114). Die Kinasen sind meist organische Kérper von nicht 
ekannter Zusammensetzung (vgl. jedoch die Aktivierung der Pan 
pase durch die Gallensiiuren, § 121 C.), es kommt aber auch eine 
ung durch anorganische Kérper yor, so die Umwandlung des 
ins in Pepsin durch die Salzsiiure des Magensaftes (§ 110). Die 
¢ der Fermente kann durch gleichzeitig anwesende organische und 
ische Substanzen in mannigfacher Weise beeinfluft werden, sowohl 
e einer Férderung wie einer Hemmung; es fehlt aber noch an 
aren Erkenntnis der Art dieser Einwirkungen, die offenbar nicht 
n derselben Weise zustande kommen. Es gibt schlieflich auch 
h wirkende Hemmungskirper fir die verschiedenen Fermente, 
mente, die entweder nattrlich vorkommen oder ktinstlich durch 
a des Ferments in den tierischen Kiérper erzeugt werden kénnen, 
Iben Weise wie Injektion eines Toxins zur Erzeugung eines Anti- 
ihrt (vgl. pag. 45), 

e Bezeichnungen fiir die Fermente werden gebildet, indem man 
Bezeichnung des Stoffes, auf den das Ferment wirkt, die Endsilbe 
uingt. So bedeutet Amylase ein Ferment, welches Amylum spaltet. 
Bezeichnung noch priiziser zu gestulten, setzt man den Namen 
nentes zusammen aus der Bezeichnung des Stoffes, auf den es 
nd der Bezeichnung des dabei entstehenden Produktes, z. B. be- 
umylo-Maltase ein Ferment, das Amylum in Maltose umwandelt, 










\ 


[86] Formente, Fotte. 


Nach der Wirkung unterseheidet man: 
1. Kohlehydratapaltende Fermente. 


a) Diastatische Fermente — welche die Polysaccharide (Stirke, 
in Dextrin und Maltose umwandeln: das Ptyalin des Speichels (§ 101) sa und ides, 
saftes (§ 114. 1), die Dinstase der keimenden Getreidekiirner. AnBerdem komm) 

Fermente noch vor in: Darmsaft, Galle, Blat, Lymphe, ee Leber, io sa 

b) Invertierende Fermente — welche di hea anette Mono 
spalten: Saccharage (Invertin) spaltet Saccharose in Daxkces und Livulose, — 
spaltet Maltogo in Dextrose, — Lactase spaltet Lactose in Dextrogo und Gala 
vertioronde Fermente kommen vor allem in dem Darmsaft vor (§ 122, 1). Da 
findet sich besonders reichlich in der Hefe. 

c) Glykolytische Fermente — welche Dextrose zerstéren; ihre 
ist noch zweifelhaft. 

2, Fettspaltende Fermente — welche Fette in Glycerin und 
spalten: die Lipase (Steapsin) des Pankrens- und Magensafles G1 114. TH, 11) 

3, Kiweibspaltende Formente — welche die RiweiBstoife in Albay 
Peptone und weiterhin in Aminosinren spalten: das Pepsin des Magensaftes (§ 
EiweiB aur bis zn Pepton ab, das Trypsin des Punkreassaftes (§ 11d. It) TE) baut } 
an den Aminosiiuren ab, das Erepsin dee Darmsaftes (§ 122) greift dic echt 
kirper nicht an, spaltet’ aber Albumosen und Peptone, sowie auch Casein bis zu d 
siluren. Eiweifspaltende Fermente kommen auch in manchen Pflanzen vor (§ 126 

4. Nucleinsiurexersetzende Fermente — welche den Abban de 
siiure im Stoffwechsel bewirken: die Nuclease, welche die Noeleinsiiure in Ne 
und die Gbrigen Bestandteile spaltet, die Adenase ond Gaanase, welche di 
nierung der Aminopurine 2u Hypoxinthin und Xanthin bowirkt, dio Xanthin 
welche die Oxydation an Xanthin and Harnsiiure bowirkt, endlich das urico 
Ferment, welchos die Harnsiuro weiter abbant (§ 163). Diese Fermento sin 
schiodenen Organen nachgewiesen worden, so in Milz, Lunge, Leber, Darm, Musk 

5. Die Arginase — welche Arginin in Harnstoff und Ornithin xerlo, 
dio Urease — welche Harnstoff in Koblenstiure und Ammoniak spaltet (3 160). 

6, Gorinnungsfermonte — welche lsliche Eiweifstofe ausfillen: da 
forment, Thrombin, welches das Fibrinogen in Fibrin amwandelt (§ 26), das L 
Chymosin, welches das Qasein der Mileh ansfillt, im Magen> und Pankreassaft (§ 

7.Oxydative Fermente — wolcho dic Oxydation schwer oxydabler § 
bewirken, Oxydasen. Man unterscheidet: 

a) direkte Oxydasen — welche den moleknlaren Sauerstoff de 

aktivieren vermigen. 
b) indirokte Oxydasen, Peroxydasen — welche nar in Gege 
Poroxyden wirksam sind, indem sie ang diesen aktiven Sauerstoff abspalten, 
genusen bexoichnot man Stoffe, welche durch Aufnabme von Sauerstof’ ang di 
Peroxyde tibergehen und nun von den Peroxydasen gespalten werden kénnen; die 0 
sind selbst nicht formentativer Natur. Die dirokten Oxydasen sind ans Oxygi 
Peroxydase zusammengesetat. 

¢) Katalasen — wolcho nur aus Wasserstoffsuperoxyd uktiven San 
spalten, aber keine anderen Peroxyde xerlegen, sie sind daher yerschieden von 
oxydasen. Katalase kommt im Blote, aber auch in allen tierischen und fast al 
lichen Geweben vor (§ 32). 

Dio Fermente vermégen nicht nar kompliziert gebaute Kérpor abzabaner 
kiinnen auch in amgekehrter Richtung wirken, Synthosen auafthren (vgl. die | 
bildung § 111). 











6. Die Fette.’ 


Die Fette kommen vorzugsweise reichlich im Tierké) 
wobl in allen Pflanzen vor, hauptstchlich in den Samen ( te 
Cocos, Mohn), seltener im Fruchtfleisch (Olive) oder in der War 
Papier bewirken sie charakteristische Fettflecken. Sie sind unlé 
Wasser, lislich in Ather, Chloroform, Benzol, Aceton, Schwefelkol 
weniger leicht in Alkohol. In wisserigen Fidasigkeiten kinnen d 
eine auferordentlich feine Verteilung in os mikroskopiseher Fettt 
erfahren, eine Emulsion bilden, und zwar entweder, wenn man 
schleimigen oder Eiweif- oder Seifenlisungen schiittelt, oder we 









Fete, 


velche geringe Mengen freier Fettsiiuren enthalten, mit 
= enbriagt wobei sich Seifen bilden, 

¢ Fete sind eines Alkohols, des Glyeerins, 

1 Dacanerear ae ie cerylester oder die Glyceride 

iren. Werden neutrale Fette mit Wasser tiberhitzt oder mit ge- 

Fermenten (Steapsin, Lipase s. S. 19) behandelt oder der Faas 

en, 80 zerlegen sie sich unter Aufnahme von H,Q in Gly: ‘ 

ie Fettsiuren, von denen die letzteren, falls sie fichtig 

tnzigen Gerach verbreiten. Mit kaustischen Alkalien behan 

sie die gleiche Zerseteung: die Fettsiiure bildet in diesem 

Alkali eine salzartige Verbindung (Seife); der Prozeb wird deswegen 

seifung bezeichnet. 


yon 
3 Glycerin — ist ein dreiwertiger Alkohol GH,< On. Es ist eine fart- and ge 


siiB schmeckende, sehr hygroskoplache Fliissigkolt, in Wasser oder Alkohol in 
‘haltnis Wslich, in’ Xthor waldslich, 
+ Fettsiuron — welche in den Fotten vorkommen, gehdren zwei verschiedenen 


+ nitmlich: 
Gesittigte Fettsiinron von der Formel On, 0,. | 







seisensiiure: " 10. Myristinsdare: ©, 
sigsivure: etn 11. Palmitinsilure: €,, | 
opionsiure: CH,O,. mh 
ttersinre: outs gdh 0. 
14, Arachinsiiure: ©, 


lori : 
eiaeatt ie 15. Hyiinasiinre: Oy Hye, 


prylsiuro: 0,1), 0, 16. Corotinsiiure: Cy, at | 
prinsilure: C,, H., 0,- 17. Molissinstiure: (y, Hi, O,- 

vrinsiure: (,, 1,,0,. 

o diesen kommen im menschlichen und ticrischen Fett hauptsiichlich vor die 
t+ und die Stearinsiore, — spiirlich ond inkonstant die Myristin, Laurin-, 
upryl, Ospron- und Buttersiure, 

| O-reicheren Fettsiiaren sind:konaistent nnd vertlichtigen sich nicht; die C-irmeren 
tive 8) sind Sliglissig und flachtg, schmecken brennend gauor, riechen ranzig. 
Ungesittigte Fettsiuren, und zwar Sinuren der Acrylsiurereihe von 
1 OnHjn—20,. Von diesen kommt fiir den ticrischen Organismns nur eine in 
die Olsiture C,, H,,0,. 

( Verbindungen des Glycerins mit der Palmitin-, Stearin- und Olsinre beifem 
4, Stearin nnd Oloin, 








SO. Og Hys O 40.0, Hy, O 
0,1, —0. 0, 1,0 0. w8- Gn 1,0 
NO. 0), 1, 0 On i, 0 
Stearin, 
Op Hy 10 Oe On Hei, 





¢ Schmelzpnnkt des Palmitins ist 62°, der des Storing 715°, das Olein orsterrt 
Die Fette sind Gemengo diesor drei Glycoride; je mehr Olein sic enthalten, tm 
: sind sic bei gewohnlicher Temperatur und umgekshrt. Das Fett Nougeborner 
thr Palmitin und Steurin als dax der Erwachsenen, welches mehr Olein besitat. 
t anch Fete, in denen die drei Alkoholgrnppen des Glycerins mit rerschicdenen 
| varbunden sind; so ktinnen 2wei und auch droi verschiedene Fettsiuren in daw 
intraton (Bomer ). 

to woitare Klasse von Fetten (auch Wachse genannt) enthilt an Stelle des Gly- 
hore aliphatischo oinwortige Alkoholo. Dagn gehirt das Walrat, eine 
g des Cotylalkohols O,oH,,0 mit der Palmitinsiure 0,,H,,0,, — das Pett 
eldrtse der Vigel, cine Verbindang dos Oktadocylalkohols (,,H,,0 mit der 
re Oy Hye 0, 
dich 





es nnch Fette, in denon an Stelle des Glycorina ein sromatlaemas 
ger Alkohol auftrity, das Oholestorin™ O,,H,, (OH); sie finden si 
er Schafe, im Blnte von Siiugetioren und Vigeln, in der Lymphe, im Gehirn, is 








wy wette, ohlebyarate, 


der Vornix caseom, in allen keratinésen Substanzen (Hanre, Federn, Hafe naw.) 

kommt anch im freien Zustand yor, im Blut, Dotter, Hirn, Galle, Ex eine 

von Korpern, die dem Cholesterin verwandt sind, sie werden als Sterine xosa 

Die Sterine des Pflanzenreichs (Phytoxterine) sind von denen des ‘Tierrelehs 
Im AnschlnB an die Fette sind ala fettahnliche are WEY 

dieser Bezeichnang werden alle in den Fel itteln Nislichen Stotfe 

also auch das Cholosterin) aufzafthren: 


Bes Lecithine — sind esterartige Verbindangen der Glycerinphos 


o,u,Zolt, ond zwar mit 2 Fettsiureradikalen (Patmitins, Stearin- oder Ols 


es 
oHSPO 
OH 
seits and dem Cholin (Primethyloxithylammoniumhydroxyd) 
MOI 
sdicn), andrerseits. 
“oH 


Die Konstitution des [Distearyl-] Lecithins ist daher: 


Die Lecithine sind untoslich in Wasser, quellen darin aber in cigenartig 
Ceystlatiecrs a: sic sind Wslich in Atkohol, Chloroform, Ather. Sie finden 

tierischen und pflanzlichen Zellen, besonders reichlich in der Nervensubstanz, 

im Sperma. — Die Lecithine sind die am besten bekannten Glieder wus sine: 
Grappe fettibnlicher Verbindangen, die als Phosphatide snsammengefabt 

sind churakterisiert durch den Gehalt an Phosphorsaiure und sticksto 
Basen, Dazu gehiren 2. B. das Jocorin (vgl. § 27, If. § 116, 2), das Prota; 
Corebroside (§ 240, 2). 

Quantitative Bestimmung des Fettoe, — Die xn untorsuchende S 
vollstiindig getrocknet, fein pulverisiert und dann durch Ather im Extra) 
(Soxhlot) das Fett (allerdings auch die fibrigen in Ather lislichen, fotthhnlichen 
extrahiert; nach Verdampfon des Athers wird das Fett gewogen. 


7. Die Kohlehydrate.” 


Die Kohlehydrate kommen besonders reichlich im Pflan 
in geringeren Mengen auch im tierischen Korper vor. Sie haber 
zichnung dayon erhalten, dab in ihrem Molekiil neben C stets V 
und Sauerstoff in dem Verhiltnis, wie im Molekiil des Wassers 
zwei Atome H ein Atom © enthalten ist. Alle sind fest, ohn 
entweder stii schmeckend (Zuckerarten) oder doch leicht durch 
Siiuren in Zucker umzuwandeln. Sie drehen das polarisierte Lich! 
nach rechts oder nach links. Trocken erhitzt, riechen sie nach 
sie firben sich mit Thymol und Schwefelsiure rot. 

L. Die Monosaccharide (auch Hexosen genannt) — 
Formel ©,H,,0, leiten sich durch Oxydation yon sechswertigen 
ab. Die Oxydation kann dabei entweder an einer primiiren ode 
sekundiiren Alkoholgrappe erfolgen. Im ersteren Falle entsteht e 


der durch die Gruppe —y charakterisiert ist, ein Aldehy 
Monosaccharide werden ie Aldosen genannt: 


Reaktionen des ‘Traubermznckers, 






: CH, .OH — CH.OH — CH. OH —CH.OH — CH.OH — 
_ CH, .OH — CH.OH — CH.OH—CH.OH — CH, OH — 


. 
die Oxydation an einer sekundiiren Alkoholgruppe, so ent~_ 
1 Kérper, der durch die Gruppe —C— charakterisiert ist, ein 


Il 
0 
solche Monosaccharide werden daher Ketosen genannt: 
CH, .OH — CH, OH — CH. OH — CH. OH — CH. OH — CH, OH 
CH, .OH — CH ,OH — CH. OH — CH, OH —C— CH, .OH . 


{| 
Oo 

ist eine groBe Zaht verschiodener Monosaccharide bekannt (tells in der Natur vor= — 
twils kiinstlich dargostollt); sie unterscheidon sich voneinander darch dio riimm- 
sarang der mit den C-Atomon verbundenen H- nnd OH-Gruppen im Molekiil. 
sch kommen in Betracht: 
Dor Tranbenzucker (Glykoxe, Dextrose) — im ticrischen Korpor in etingen 
i Blut, Chylos, Muskel, Leber, Harn vorkommend; in grofen Mengen im 
4s mellitas, Er entsteht bei der Inversion des Malzzuckers, des Rohrauckers (meben 
des Milchznckers (neben Gulaktose), ferner des Dextrins, Glykogens, der Stiirke. 
Terdanung entsteht ans den Polysacchariden durch die diastatischen Fermente 
faltose neben nur wenig Dextrose und ang der Maltose dann dareh die 
{m Pflanzenreiche ist er verbreitet in den siifen Siiften mancher Fritchte and 
ym dort gelangt er in den Honig). — Der Traubenzucker ist der Aldehyd des 
ines sechswertigen Alkohols (in den Vogelbeeren yorkommend). Rr 

oder mit 1 Molekil Krystallwasser) in vierseitigen Prismen, die sich oft =u 
ad Knollon zusammengrappieren. Er dreht die Ebene des polarisierten Lichtes 
# (daher Dextrose), spexzifische Drehung + 52,5° (in frisch bereiteter, nicht 
Lésung viel hihor, + 106% Multirotation), Durch Garang mit Hefe zerfallt 
hol und 0,, durch gewisse Spaltpilze in 2wei Molekile Milchsiuro, In alkaliseber 
wirmt, zersetzt sich der Tranbenzucker, in sanror Lisung ist er bestiindig. Der 
sker wirkt in der Wirme auf viele Metalloxydo reduzicrend, woranf die zum 
dienenden Reaktionen zum Teil berahen (s. unten Reaktionen 1, 2, 3). Bei der 
des Tranbenzuckers entsteht zuerst die cinbasische Glykonstiure, sodann die xwei~ 
hokersiure. 
aktionen des Traubenzuckers. 
allen anf Zucker xo untersuchenden Flissigkeiten wird zuerst etwa vorhande 
treh Aufkochen bei schwseh saurer Reaktion entfarnt. 
Jie Trommersche Probe: — Man setet xu der za untersuchenden Flissigkeit Kali- 
‘nlauge, daranf tropfonweise eine yerdinnte Lisang von Kupferaulfat: der sieh 
fildende flockige, blangefirbte Niederschlag von Kupforoxydhydrat On (0) 
o der Flissigkeit (falls Zucker vorhanden ist) mit blaner Farbe auf, Man 
de fast 2um Sieden: dabei wirkt der Zucker reduzierend anf das Kupferoxyd- 

hildot sich ein Nioderschlag yon braunrotem Kupforoxydal Cau, 0 oder von 
Kupferoxyduthydrat On OH. 

sobr goringen Zuckermengen kann eine Rinengung der Fiiissigkeit im Wasserbade 
h snurer Reaktion notwendig sein. Wenn kleine (unter 0,5°/,) Zuckermengen 
noniak, Harnsilure, Krentinin vorhanden sind, kann statt des gelben Nieder 
Mo gelbe Losung des Kupferoxyduls cintreten. Zu reichlicher Zusatz von 
at (der stets zo vermeiden ist) hat die stirends Ansscheidang schwarzen 
tyds OnO sur Folge. 
Bétigers Probe — mit alkalischer Wismutoxydlisung — [nach Nylander 
in folgender Znsammensetzung: 2g Bismat, subnitrionm, 4 Natr. Kal, tartaric, 
‘onlange vou 8°/,). Hiervon gebe man lem? auf 10cm der xn untersuchenden 
« Wird mebrere Minuten gekocht, so bewirkt der Zncker eine Rednktion bis au 
m Wismut, welchos als schwarzer Niederschlag ausfillt, 
Mulders & Nenbauers Probe: — Man macht die xa untersuchonde Flissigkelt 
sanrem Natron alkalisch, figt cine Losung von Indigocarmin bis zur blanen 
ingn and erbitat: durch Reduktion des Indigblau zu IndigweiS geht die Parbe 
urpar, rot, gelb tiber. Nach dem Abkihlen mit atmosphiirischer Luft gesebittelt, 
Flissigkeit wieder die blane Farbe an, 














1s WU RUVIE OH TNA DUSTIN UES CTRVOTZICKOTS 


4. Moores & Hellers Probe: — pie Flisssigkeit wird mit Kali- oder 
bis zur stark alkalischen Realtion versetst and gekocht: ¢s ontsteht gelbe, 
braunschwarze Verfirbung durch Bildung von Humussubstanzen; wird nach dey 
mit konz, Schwofelsiare angesinert, go entsteht der Geruch nach gebrannts 
(Caramel) und Ameisensinre. 

5. Molischs Proben: — ', cm? dor an Filissigkeit versete 
2 Tropfen eincr 17°/,igen alkoholischen #-Naphthol- oder fateua 
giebt man 1—2cm* konz, Schwefelsiiare hinza und schittelt rasch. Bei Geg 
Zucker firbt sich das a-Naphtholgemisch tief violett, die Thymolprobe tief rot { 
reaktionen, 8, 18), 


6. Phenylhydrazin) t — Zu Tem® dor Piliasigkeit setzt man im 1 

2 Messerspitzen salzsanren Phonythydrazing und 3 Messerspitzen easigsauren Natro 

bis sur Laisang (eventuell unter etwas Wasserznsatz) und setzt das Glaa 1 Stu 

ein kochendes Wasserbad: bei Anwesenheit von Dextrose scheiden sich char 

mikroskopische Buischel feiner, langer, gelb gefiirbter Nadeln von Phonylglyk 
welches in Wasser fast anldslich ist, bei 204—205° schmilzt. 

7. Girungsprobe: — Man versetzt die za untersuchende Flissigkelt mit 

Milt damit ein Reagenaglas vollstiindig, vorschlioBt die Méindung mit dem Finge 

Loft hineingelangt, und stellt das Reagensglas umgokehrt in eine mit Qnecksi 

Schule. (ZweckmiBig kann man auch statt desse, 

met nanntes Gikrungerdhrehen (Fig. 1) verwenden, bei de 

i Quecksilber zam Verschiu® braneht.) In der Wiirme 

oo 50) erfolgt bald Zerlogung des Tranbenzucker 
Hefe in Alkohol and Koblensiiure: 

0,11, 0, = 20, H, OH + 200, ; 

die Kohlensiiure sammelt sich im oberen Toile des Ri 

an. — Eis ist ndtig, awei Kontrollproben anzustellen: 

Hofo mit suckerfreier Fiissigkeit, am ausznschlieh 

Hefe selbst Zucker enthilt; es dart keine CO,-Bntw 

treten, 2, Dieselbo Hefe mit zuckerhaltiger Fifissigk: 

au vargewissern, da die Hote auch garkrattig ist. 


Quantitative Bostimmong des Traube 


1. Durch Titrie mit Fehlingsch 
— (Die Methode beraht auf der Trommerschan Pro 
Fehlingsche Lisung beim Anfbewabren sehr seba 
wird sie jodesmal yor dom Gobrauch nou herzestollt, 
gleiche Volamina dor beidon folgenden Flissigke! 
under mischt: T. 34,0309 reinos, krystallisiertes | 
(Cu80, + 51,0) mit Wasser x0 500 om* gelost, I. 1% 
lisiertes weinsuures Kali-Natron (Seignettesalz) in wi 
gelost, dian 100 cw* Natronlangy, die 50g Natron 
halten, mit Wasser anf 500cm* anfgefillt. (Die 
verdirbt anch bald und muf daber hitufig frisch her; 
den.) 20 em® der Fehlingsehon Losung mit 80 en® 
diinnt, entaprechen 0,19 ‘Traubenaucker. (Das Re 
migen des Tranbenguckers ist jedoch jo nach der 0 
Gradulertor Kiwhormecher or Zuckerlisung und der Verdinnung der Fuadinge 

Gniagateneen etwas verschieden'(Sorhlef*); man mu daher bei 

mung genan nach der Vorschrift yerfahren.) 


Ausfihrong der Bestimmang in zuckerhaltigem Hara: 200 
scher Losung, mit 80cm? Wasser verdinnt, worden xam Kochen erbitet. Aus ¢ 
148t man den Harn (der 5—10mal verdiinnt worden ist) in kleinen Portionon x1 
kocht jedesmal 2 Minuten lang. Man setzt so Innge Harn zn, bis die blan 
Flissigkeit (nachdem sich der Niederschlag sbgesetxt hat oder nachdem man 
schnell abfiltriort hat) vollstindig verschwunden ist, Auf Grund dieser noch xie 
nanen Bestimmang filbrt man nun eine zweite aus, bei der man die gofundene 
auf einmal xufliefen 1aBt, nnd stellt fest, ob nach 2 Minuten langem Kochen die 
noch blag ist. Ist dies der Fall, so nimmt man bei der nichaten Bestimmung 
mehr, ist dagegen die Filissigkelt schon villig ontfirbt, so nimmt man etwas Ha 
In dieser Weise fithrt man fort, bis bei zwei Bestimmungen mit our wenlg ve 
Harnmengen die Fitissigkeit nach dem Kochen das eine Mal noch blan, das 
dagegen entfirbt war. Die zwischen den beiden gefundenen Werten in der Mi 












Gulaktose, Livoloss, Pentosem. Disaccharide. 


n entspricht dann gonan 20cm* Fehiingacher Lisung, enthalt also ; 
tor. 


Durch Polarisation. ** — Dio Methode beruht auf der Higenschaft des ‘I 
‘Ebene des) Lichtes nach rechtsandrehen. .SpozifischesDrehu 

* nennt man den Grad der Drehung, welchen lg ales optisch akti 
in lem* Wasser golist, bei 1dm dicker Schicht cae des Rohires de 
fir gelbes Licht bewirkt; dieses ist fiir Dextrose = + 52,5°. Da die Drehy 
ortional ist der Menge der in der Flissigkeit gelisten Substanz, so gibt 
blenkang eo fiber den Gohalt der Tiga an der optiseh wit 
3eneichnot x beobachtete Drehung, [a] das spexifische ung 

des Rohres, S oie Anzahl der Gramme der optisch wirksamen Substanz in 


7 Mar Ansfthrung der Bestimmung dienen: Der Soleil~Ve 
das Polaristrobometer von Wild oder der 
arpa ippich, Landolt. 





io Galakto: bildet zusammen mit Dextrose den Milchzucker (Lactose) 
diesem 7 ler hydrolytischon Spaltang im Kirper durch die Lactase. § 
je von Gummi und Schleimstotfen, auch als Ze m 


ierten Lichtes rack ott (spezifische Drehung = + 83,88"). Thr Pheny! 
193°. Sie wirkt redazierend, gibt die Reaktionon der Dextrose, ist 
ydation liefert sie Sehleimaiinre, 
tie Liivulose (Fructose, Frnebtzucker) — findet sich neben der Dextrose 
lonig. Sie ontsteht bei der Inversion des Inulins (a 
‘n Dextroge bei der Inversion des Rohrauckers, im Darmkanale durch iver 
4 kommt sie (selten) im Harne vor, dabei zugleich im Blut (Zosin a, 
( Fallen fanden Neuberg u. Strauss? Livulose im menschlichen Blutserum 
monsehlichon Gewebsfliissigkeiten (Ascites, Pleuraflissigkeit, wird von Ofmer’* 
Nach Girber vu. Griinbaun'® kommt physiologisch Livnlose in betrichtlichen 
Fruchtwasser von Rind, Schwein und Ziege vor, Langatein a. Newb fanden — 
ne neugeborener Kilber. -— Die Lavulos ist eine Ketose, Sie krystal poe 
tht dio Ebene des polarisierten Lichtes nach Hinks (daher Liiynlose); 
amégen — 90,2 bis 93°. Sie bildet dassolbe Ozazon wie die Dextrose, wirkt 
wWusierend; sie vorgtirt mit Hefe, aber schweror als Dextrose, 


such ve nee mft weniger eal it mehr ole 6 Aken Von dla 
mur noch in Betracht die Pentosen, 0, Dieaclben sind in 

F “Anhydride, der Pentosane (0, Hy O,e (vel. pig 6)""inr Ptaenenselehe, wal 

im tierischen Kirper sind sie als Spaltungsprodukte der Nucleoproteide 

con (vg pag. 16) und pathologisch im Harn nachgewiesen, Von den Organen ist, 

‘am reichaten an Pontose das Pankroas (248°), des trockenen (Organs) (Greenad™ 

lesolben Reduktionaproben wio der ‘'ranhenaucker und mit Phenylhy 

Hache Verbindungen, — sio sind dagogen nicht mit Hofo vergirbar und Mofern 

zen mit Salasture keine Livalinsiure (wie die Hoxosen), aber reichlicho Mengen 

(Git Salzsdinre und Phloroglucin resp. Orein geben sio churaktoristischa Farbes~ 


Die Disaccharide — von der Formel ©,, H,. 0,, sind Verbin- 
von zwei Molektilen Monosaccharid unter Austritt von H, O: 


©, Hs 5 + Cy Hys Op —H, O = Cy, Hz 04). 
ochen mit Siiuren sowie durch die invertierenden Fermente werden 


re Bestandteile zerlegt. Sie sind nicht direkt vergiirbar, sondern 
4 ihrer Spaltung in die Monosaccharide. 


Die Maltose (Malzxucker) — = 1 Dextrose + 1 Dextrose — 1 1, 0. Sie entsteht 
mwirkung der diastatischen Fermente anf Stirke und Glykogen; durch Maltase 
feiter gespalten in Dextrose. Sie krystallisiert in feinen, 2u Warzen vereinigten 
t 1 Molektl Krystallwasser, Weslich in Alkohol, wird ans alkoholischer Lisung 
or in nadelformigen Krystallen avsgeffillt (Dextrose nicht); sie Ureht rechts, spex. 
=-+ 140% Das Maltosazon ist in heifem Wasser Kislich, scheidet sich beim Er 








[87] Lactose. Saccharose. Polysaccharide, 


kalten in gelben Nadeln ab, schmilzt bei 206°, Maltose wirkt redusierond, 
ctrose. 


Dextrose KRapfernyd (Bary 
Maltose nicht. — Als eine eS der wird die Donations 
(vielleieht nar Usrtwe ies 7}; das Oxazon derselbon sehmilzt schon bei 1 

2 Die Lactos itchzncker) —=1 Dextrose ++ 1 Galuktose —1 HO, $ 
nur in der Mileh selten im Harn). Durch die Tactase wird sie in ihre Ko) 
zorlogt, Mit Peiathes Bierhofe grt sie nicht, dagogon wird sie durch die s¢ 
Milchznckerhefen xuniichst gospalten und dann vergoren. Durch verschiodene Bakt 
sie in Milchstinre verwandelt. Lactose ist in Wasser und namentlich in Alkohol 
Wslich als Dextrose, schmeckt wenig sti8; sie krystallisiert mit 1 Moloktil Kryst 
sie dreht rechts, spez, Drehung = + 52,5°. Das ist in heifem Wasse 
leicht Wslich, seheidet sich go Erkalten in gelben, 20 kugeligen Aggregaten + 
Nadeln ab, schmilxt bei 200% Lactose wirkt redazierend, aber langsamer ale 
reduziert im Gegensatze za Dextrose nicht Berfoeds Reagens (schwache Lisang 
sanrom Kupfer, der etwas Essigsiure zngesetzt ist). 

8. Die Saccharose (Rohrzucker) — = 1 Dextrose + 1 Lavulose — 1 
Zuckerrohr, in Zuckerriiben und einigen anderen Pflanzen verbreitet. Im Darmi 
durch das Invertin in thro biden Komponenten goxpalton. Durch Hofo ist sie 
aber nicht direkt: sie wird durch ein in der Hofe vorhundenes Invertin zuniichst 
woranf die Giirung erfolgt. Die Saccharose krystallisiert in Prismon, sie ist lei 
in Wasser, in absolutem Alkobol fast unlislich. Sie droht rechts, spez, Drebung = 
Die bei der Spaltung der Saccharose in ihre beiden Komponenten entstehende 
dreht stiirker nach links als die Dextrose nach rechts; durch die Spaltung wir 
Reebtadrehung der Saccharoge in Linksdrebung umgowandelt; dahor die Bexei 
Invertierang, Invertin, Invertzucker (das bei der Spaltung entstehonde Gemisch vo; 
und Lavnloso). Die Saccharose bildet mit Phenylhydrazin kein Osnzon, sie wit 
reduzierend. 


Ill. Die Polysaccharide — yon der Formel (Cy Hyp Og)n, 8 
bindungen zahlreicher Molektile Monosaccharid unter Austritt von 
Die GréBe des Faktors n ist noch unbekannt, jedenfalls ist 1 
Molekulargréfe sehr hoch. Es sind amorphe Kérper, ihre Lésunge: 
dieren nicht oder nur sehr schwer. Durch Kochen mit verdtinnte: 
oder durch die Einwirkung von Fermenten werden sie hydrolys 
in die entsprechenden Zucker umgewandelt. 


1. Das Gly kogen — (Bigenschaften, qualitativer Nachweis, quantitative B: 
vel. § 116), in geringen Mengen in fast allen Organen dex Kirpers yorkommend 
in Leber and Muskeln. Es dreht die Ebene des polarisierten Lichtes nach rechts; 
Drehung (a]p = + 196,57° (Gatin-Gruzewska®), Kx wirkt nicht redusierend. 

2 Die Stirke (Amylam) — tells in den ,mebligen* Tellon vieler Pils 
organisiorten, innerhalb der Pflanzenzollen sich bildenden, geschichteten Kirnchen 
oxzentrischom Kerne bostehend, toils, und xwar seltenor, ungeformt in den Pianzen vor 
Der Durchmesser der Stiirkekdrnchen wechselt bei verschiedenen Pflanzen orhebli 
2. B. bei der Kartoffol 0,14—0,18 mm, im Runkelriibonsamen nur 0,004 mm. Ir 
Wasser yon 50—80° quellen die Stiirkekiirner zn einer gelatinisen Masse, den 
kleister, MitJod firbt sich Stiirke blan, beim Erhitzen verschwindet die Farbe und 
Erkalten wieder, Sie reduziert nicht, Man hat in der Stirke xwei Bestandteile ante 
die Amylose, welche die Jodreaktion gibt, aber keinen Keister liefert, und da 
poktin, wolches beim Kochen Kloister liefert, aber keine Jodreaktion gibt. Dur 
wit vordiinnten Stiuren wird die Stirke in Dextrose umgewandelt, durch die di 
Fermente in Erythrodoxtrin, Achroodextrin, Maltoso (und nur wenig Dextrose). 

3. Die Doxtrine — sind Kirpor, welche xwischon Glykogon und Stirke 
ond Maltose andrerseits stehen; sie worden bei der Einwirkung yerdinnter Si 
der diastatischen Fermente anf Stirke oder Glykogon als Zwischenprodukt gebilde 
in Wasser stark klebend ldslich, durch Alkobol filllbar, drehen ‘de Ebene des pi 
Lichtes nach rechts (daher Dextrin), spex. Drehung ungefilhr +195". Von Jod 
blan gofiirbt (Amylodextrin), rot gefirbt (Erythrodextrin) oder tiberh, 
goflirbt (Achroodextrin), Slo giiren nicht, Amylodextrin redusiert Fehlingse 
nicht, wohl aber wirken Erythro- und Achroodextrine reduzierand, 

4. Das Innlin — findet sich in der Warzel der Cichorio, des Léwonzabnes, 
in den Knollen der Georginen (Dahlia varinbilis). Bei dor Spaltung durch Situ 
es Liivulose; es steht zn dieser in derselben Bozichung wie die Stirke zur 
Als Zwischenprodukt entsteht Livulin (dem Dextrin entsprechend). Spexitisch 
des Innlins = — 36—87°; durch Jod wird os nicht gefiirbt. 





as 








Den Kohlehydraten nahostehentle Kirper. Stoftwechselproe’ nite. 


+ Gummi — findet sich im Pianzenreiche in den Siiften besonGters der 

i ee Neer ree eee sollen gummiartige Stoffe gefunden worden sein, 
a forner im Blut and Hara, Belm Kochen 
liefert Gummi einen Kapforoxyd reduzierenden Kirper. 

: woalinione _- oe age aller Pflanzen (auch in dem Mantel der 

bropodony und dor Schlangenhat 

Joreh Schwefelsiinre und Jod blan geflirbt. Du 

Idet sich Dextrin und ein fiir die Collulose eeetieotsiee 

ose, die sodann in zwei Molektile Dextrose zerfiillt. Im Darme der 

durch Bukterien gelést. Konzentrierte Salpetersiiure, mit Schwefelsiiare pe 


cone (Q, Hy O,)ay 
oh, Kloio nsw. enthalten, beim Kochon mit Schwefelsinre liefert es Xylos: 
s Araban (in Gummi arabicum, Kirschgammi, Ribenschnitzoln usw.) die Ar 


V. Den Kohlehydraten nahestehende Kérper. ‘| 


Glucosamin, O,H,,0, (NH,) — entsteht durch Einwirkung ranchender Salzsiiare 
tin 0,,H,)%,0,, (dom Bestandteil der Panzer aller Gliedertiere), ferner ale 
sprodukt vieler Glykoproteide (pag. 15) wie auch mancher Proteins (Bier 
und die Gbrigen Kiweifstotfe des Kiklars, Seramalbumin, Kiwei® aus Kigelb), 
dem Chondrosin, einem Zersetzungsprodukt der Chondroitinschwefelsture (vet. 
enthalten. Das Gincosamin leitet sich vom ‘Tranbenzncker dadurch ab, daB eine 
pe durch NH, ersotat ist: 

Dextrose: CH,.OH — CH.OH — CH.OH — CH,OH — CH,OH — OOH. 
Glucogamin: CH,.OH — OH,OH — CH,OH — CH,OH — CH.NH, — COH. 


ISR REA aU RGee OTN. 0) Snail Ie popaaclec Wosse\tn Jhuabian Mrogea ia im 

Harn yor, in griBeren nach Finfihrang einer sehr grofen Amabl Kérper der 
then und fetton Reiho. Sie ist im Chondrosin zusammen mit dem Glucosamin 

(s.0,). Die Glykuronsinre Icitet sich durch Oxydation vom ‘Trauhenaueker ab, 
le Oxydation am demjenigen C-Atom erfolgt, welches am andor Ende der Katte 
(die Aldehydgrupps : 

Dextrose: CH, .OH — CH.OH — CH.O — CH.OH — CH. — Con. 
kuronsinre:  GOOM — OH.OH — CH.OH — CH.OH — CH.OH — COH. 
ohangsweise wird hier besprochen der eigentlich nicht 2 den Zuckern gehdrige, 
nockende Inosit, O, H,(OH), = Hexahydrohexaoxybenzol, Muskelxneker, 
toker, in Muskeln, in Lange, Leber, Milz, Niere, Him vom Ochs, Niere des 
im’ Harn und in’ Kohinocokkontlissigkoit. Im Pilangenreich yerbreitet, namentlich 
‘fn (Legumninosen) und im 'Traubensaft, Er ist optisch inaktiv, krystallisiert meist 
thlartig mit 2 Molekilen Wasser in langen monoklinischon Krystallen, in Alkobol 
er mnlislich, wirkt nicht reduszierend. 


8. Stoffwechselprodukte. 





N-freie. 

Kohlensiure, O0,. 

Milchsiiure (Oxypropionsiure), C, 1,04 = kommt in swe isomeren Forntea Yor: 
Athylenmilehsiure, CH, 08 — OH, — OOOH, kommt Im Kisper dberhanpt 
nur in sehr geringen Mengen 

,_ Athylidenmitehssare, CH, —-CHOH —COOI; e cxistieren drei Modi- 


“Optiaeh- -inaktive Milehsinro (Garungamilchsiure) besteht sus gleichen 
jer boiden folgenden. Sie ontsteht bel der Milchsiiuregirang der Koblehydrate, findet 
cilen als Produkt der Giirang der Kohlehydrate im Mageninhalt (vgl. § 109). 

Rechtsdrehende Milchsiure (Fleischmilchsinre, Paramilohs&ure) 
h unter den Extraktivstoffen des Muskels, kommt auch im Harno vor, 

) Linksdrehende Milchsinre kommt im Kirper nicht vor.) 

B-Oxybuttersinre, CH, — CHOH — CH, — COOH; Acetessigsiure, 
0 — CH, — COOH; Aceton, CH, — CO — CH,, finden sich pathologisch im Harne, 
tlich bei Diabetes (vgl. § 168). 


{(s8) Stoffwechselprodukte, 


4. Oxalsiinee, COOH — COOH — kommt als oxalsaurer Kalk im Harne yor 

be Barasiniaetiers pai es OH, — COOH — findet sich stets 
der Flissigkeit der Echinocokken, geringen Mengen ist sie in manche 
Flussigkeiten gefunden. Sie entsteht als Nebeuprodakt bei der Alkohoigirang. 

6. Citronensiure, G,H,O,— in der Mileh. 

7. Chotsiure (Cholalsiure), O,,H,,0, — in dor Galle (vgl $118). 

Il, N-haltige. 

1. Harnstoff, 400 Bah ee das Diamid der Kohlensinre SOME). ote 
der Hanptbestandteil des Harns und das hauptaiichliche Endprodakt dos Riweif 
(vgl. § 161). 

2 Guanidin ond seine Derivate. 

Guanidin, NH =C(NH,), — ist Imidoharnstoff. Mit dom Ornithi 
valeriansiiute) verbunden, bildet es das Arginin, ein Spaltungsprodukt d 
(pag. 11). Vom Guanidin leiten sich ab 

Kreatin, Methylgnanidinossigsiure, C,H,N,O, — oder 


sy= Rei) — ou, — coon, "4 
Kreatinin, 6, H,8,0 — das Anbydrid des Kreatins: N= 


(01 
Kreatin findet sich ha ich in don Muskeln (vgl. § 211), forner Fr 
Kreatinin im Harn (vg. § 165). 

3, Dio Purinkorper (Alloxarkorper®) — sind eine Gruppe von 
sich alle von einem Kern, dem Parin, C,H,N, ableiten, 


Dio Zahlen 1.—9. goben die Re 
ag, in weleher man Tone eee, a 
kerns su numerieren 

stitution der verschi re "yon oe 
lolteten Vorbindangen Ieicht bezel 
kinnen, 





Der Parinkern ist xasammengesotet ans dem Pyrimidinkern (9, 4) un¢ 
axolkern (8, 5. 12). 


A. Dio Harnsinre, O,1,N,0, — ist 2.6.8. Trioxypurin: 
9 


| 


oc ‘ 
| Seo 
HN —4 Ni 


Die Harnsiure kommt im Harne vor (fiber Bigenschaften usw. vel. § 168 
in sehr goringon Mengen im Blute, 
Durch Oryftion der Harnsiinre mit fbermangansanrom Kali entstoht 
—CH_NI 
©, 180 00 | "S00 — os kommt in der Allantoistliissigkeit un 
co. NH,” 








on (Nacleine oder Xanthin- oder Alloxurbase; 

a) Adenin, O,H,N,: 6. _Aminoparin. 

b) Guanin, O,H,N,0; 2. Amino- 6. Oxypurin. 

¢) Hypoxanthin, 0,H,N,0; 6. Oxyparin. 

4) Xanthin, O,H,N,0,; 2. 6. Dioxyparin. 

Die beiden Aminopurine; Adenin ond Guanin sind Bestandteile 
siiuren (vgl. pag. 16); bei der Spaltung werden sie teilweise in die entsprech 
purine: Hypoxanthin und Xanthin umgewandelt. 

Moethylderivute des Purins sind: Thoobromin = 3. 7. Dimethylxanthin; 
3. 7. Trimethylxanthin. 


Anorganische Westandteile, 


Die Pyrimidinbagon leiten sich yoo dem Pyrimidinkora ab; 







ie iis Die Namerlorang der Atome des Pyrimidinkerns: 


| ist dieselbe wie belm Parinkern (s. oben). 
ast 4 


Thy min, 5 erste 2, 6, Dioxypyrimidin, 
Cytosin, GAL 8 An 2, Oxypyrimidin. 
Uracil, OH,%,0,; 2 Dien Dioxypysim! in. . 
ymin ond Oytosin sind Restandteile der Nucleingiiuren; bel der 5 wird 
nm sum Toil in Uracil tibergeftihrt, welches daher ebenfalls untor A 
+ Nucleinsiinren gefunden wird (vgl. pag. 16). 

Glykokoll oder Glycin (Aminoessigsiure), CH,(NH,)—COOH, die ein~ 
ainosiure unter den Spaltungsprodukten des KiwelBes (pag. 10). Mit Cholalsiture 
dot es die vdipkeabsivaane der Galle (vgl. § 118) — mit Benzoostinre gepaart 
als Hippursiture im Harne vor (vgl. § 165). 

Tanrin (Aminokthylsulfosiure),- OH, (NH,)—CH,—SO, (OH) kommt mit 
¢ gopnirt als Taurocholstnre in der Galle vor (vgl. § 118). 


9. B. Anorganische Bestandteile.** 


organische Bestandteile kommen neben den organisehen regelmaBig in allen Flikssig- 
[ goformton Bestandteilen des Kérpers vor, Nar ein sehr geringer Teil dieser am 
n Sabstanzen ist anfillig in den Kérper cingeffibrt und an dieser oder jener Stelle 
eben, die Mohrzaht stellt einen fiir den Ablauf des Lebens notwendigen Be~ A 
far, Mit den Exkroten (Harn, Schweif, Faeces) werden danernd anorganische Stoife 
Xirper ausgeschieden; sie miissen durch die Nahrang ersetet werden, absichtliche 

¢ der Salze der Nahrung (Salzhanger, vgl. § 148) flhrt sehr bald zu schweren 

und schlieflich zum Tode. Der Gebalt der Mlissigkeiten und Gewebe des Kirpers 
neelnen anorganisehen Bestandteilen achwankt in der Norm nur in sehr engem 
sucht man experimentoll diese Verhiiltnisse xu indern, so golingt dies immer mur 
eschriinktem Umfange nad sehr bald werden darch regalatorische Kinrichtungen 

ton Vorhiltnisse wieder hergestollt, Obwohl danach an der grofen Bedeutung der 

hon Bostandteile des Kirpers fir das Loben kein Zweifel bestehon kann, so ist 
sinzelnen nur wenig Sicheres dariber bekannt. Eine groBe Rolle spiclen die an 

n Salze bei der Anfrechterhaltung des normalen osmotischen Dracks in dew 
sigkeiten und -Geweben (vgl. § 13). Aber auch anf das Mischongsverhiltnis der 
anorganischen Bestandteile kommt es in hohem Malo an, wie besonders dentlich 
rvorgeht, da® bei der Durchstrimung fiberlebender Organe (zB. Hers, § 38: 

06) Salzlisungen von ganz bestimmter Znsammensotaung (Lockeache, Ringerscho, 

» Lisung, vgl. $38) verwandt werden miiszon und anch nur ganz 

m in der Zusammensotzung der Lisang dio Verwendbarkeit beeinteiichtigen oder 


Wasser: Der mittlere Wassergehalt des ganzen Korpers betrigt nach Bischo/® 
achrenen 58,0%/,. Hr ist am héebsten beim Foetus (97.9%), schon erheblich 
beim Neugeborenen (66,4/,) und nimmt mit zunehmendom ‘Wachstum ab. Bai 
rahrungsaustande ist der Wussorgohalt des Kérpers niodriger als bei schlocht Ex- 
n das bei Chorernihrang angesetzte Fett sehr wasserarm ist. Am wasserreichsten 

den Bostimmungen von Engels*® an Hunden: Lungen (78°/,), Blot, Darm, Nieres 
irn (76%/,), Muskel (73°/,), am wasseriirmston das Skelott (34°/,); das Zahnbein 
ir 10%, der Zahnschmelz fust gar kein Wasser. Fast die Hilfte des im ganzen 
wrhandenen Wassers befindet sich in den Muskeln. 


Gase: Sauerstof?, physikalisch absorbiert und (huuptsiichlich) chemisch gebanden 
} 82); in den Gbrigen Kirperflissigkeiten nur in schr geringen Mengen. Ang Inft- 
Yiumen im Karper, die nicht danornd mit dor AuGenluft in Verbindang stehen, 
Zanerstoff allmiblich von don Wandnngen absorbiert (vgl. Magengase § 109, Darm= 
}, Pankenhble § 22), — Stickstoff, physikalisch absorbiert in geringen Mengen 
{ 83, I, ebenso Argon) und den andern Kirperiiissigkeiten, Am Stoffweebsel, in 
arganiach gebundene N der EiweiBkirper oine groSe Rolle spielt, hat der gas= 
Keinen Antell (vgl. § 86, 6, 148), — Wasserstoff entsteht durch die Giirungs. 


(89) Anorganische’ Bestandteile. 


vorgiinge im Darm und tindet sich daher Se ee ae nye 

Magengasen, geht von hier in dag Blut und die Ausatmungsluft ther (§ 86. 7). 

Ammoniak entsteht als intermodiiires Produkt beim Stoftwechsel der Ei 
Desaminiorung 


Harn (§ 169, A, 3) vor. — eeeane ist das Endprodukt der Verbrennung 
nisehen Kir dich, i chen Monge ead 
(hauptaichlich) chemiseh peesdis im Blut (§ 33. 11), aber auch in allen ander 
Aiissigkeiten und -Geweben). 


IL. Metalloide: Chior vo in Form von Chloralkalien hauptsiich! 
Korperiligsigkelten yor (Blat 0,30°/, Cl, Lymphe, Harn, SchwoiB), als Salz) 
—0,58%, HON im Ln eae ts (vB § 109), woniger oder gar nicht in don gof 
standtellon, so enthalt nach *' dio Muskelsubstanz selbst kein oder nur 
7 hesonders hohen Cl-Gehalt talk (0,288", und hoher) hat die Haut (Wahlgre 

erg™). Der mittlere Cl-Gehalt des gunzen Kirpers betrigt 0,112%/, fir den H 
edi N. 0,123%, fir den Menschen (Magnus-Lery™); beim Foetus ist der Ol 
hoher (0,25—0,27%), beim mensebliehen Foetus), or sinkt mit zanehmendem Ko, 
wie der Wassergehalt (s. oben) (Rosemann™), Durch echlorarme Ernithrang, 8 
Hunger kann nur vino geringfigige Abnabmo des Ol-Vorrats des Kirpers he 
werden, da unter diesen Umstiinden sehr bald die Cl-Angschoidung im Harn ) 
wird oder anfhort; stirkero Verringorang bis anf 80%, des Normalwerts kann du 
fitterang (§ 109) und Entleerang des abgesonderton Magensaftes nach anfen bewi 
Dareh ehlorreiche Ernithrang kann der Ol-Gchult des Kérpers stark erhiht we 
tindet nach Anssetzen der Obreichen Erniihrung cin schneller Riickgang des 
statt (Rosemann™). 

Brom findet sich in goringen Mengen (nach Justws* 0,01—0,05 in 100 
Organ, nach Labat® bedentend weniger) in allen untersnehten ticrischen und m 
‘Organea, am reichlichsten in Nebenniere, Schilddrise, Ntigeln, Leber. Boi Ol-Entz 
gleichzeitiger Binfuhr yon Na Br kann ein Teil des Clim Korper durch Br ora 
(Nencki a. Schoumow-Simanowshe", Bonniger™), 


Jod wards von Baumann® in der Schilddriise gefunden in organischor 1 
Jodothyrin (§ 192. 1) (Baumann uv. Roos"); aber anch in fast allen under 
finden sich sehr geringe Mengen Jod (Justus), 

Finor in Knochen und Zihnen in schr geringen Mengen, 0,1—0,3"), 
(Gabriel, Jodlbauer®), aber wach spurweise in andern Organen (Tarmmann'®, 
Clausmann''), ‘Nach Zafehr von Ne Fl wird Fl im Kisper urllckgehalion’( 
Tappeiner*), 

Schwefel kommt im Korpor fast nur in orgunischor Bindung vor, hi 
in den Fiwoilstoffon (Cystin, vgl. 8.11); am schwofelreichsten sind die H 
(Daring), dor Schwofelgehalt des Muskels betriigt 1,1, der ‘Trockensnbstanz (Ji 
Ta sist ciweilurtiger Form kommt Schwefél in der Galle yor (Tanrocholsinre 

el (Chondroitinsehwofelsinre), als Rhodanverbindung im Speichel (§ 100), 
a ”s far (§ 169. A. 3), In anorganischer Form findet sich Schwofel in den 
Kirperilisaigkelten und -Geweben go gut wie gar nicht, im Harn als Sulfate 
schwofelsiinro (§ 169. A.3), bel Fleischfrossern auch als unterschwollige Si 
poke kommt im Spoichel mebroror Schnocken (Dolium galea, 3°!) + 
Schulz"). 


Phosphor ist vorhanden in organischer Rindung in den Naktoo- und 
proteiden (S. 16), im Lecithin und den anderen Phosphatiden (S. 21), in an 
Bindung als Calcium- nnd Magnesiumpbosphat in den Knochen, als Alkaliphospt 
und den Kirperfiissigkeiten. Im Harn crschoint die Phosphorsiure gobunden : 
und Erdalkalion (§ 169. A. 2). 


Arson wurde als rogolmiBigar Bestandtell in gewissen Organen von Ga 
allen Orgunen von Bertrand* nachgewleson: diese Angabon sind allordings vielfac 
(Cerny**, Hodimoser , Ziemke™, Kunkel™), 


Bor fanden Bertrand und Aguthon™ konstant in tierischen Organen 
nnd Eiorn. 












Anorganischo Bestandteile, Literatur (§ 5—9), 


Uiciam kommt als Kieselstiare in vielen Organ 
der Gehalt eines Organs an Bindegewebe bestimmt seinen K 
r alone der Kieselsiiuregehalt xu (H. Schulz"), 


(. Metalle: Alkalion. Natrinm und Kalinm kommen Gberall im Kin 
ilich als Chloride, in geringerer Menge als Phosphate, Snifate, Carbonate. 
orwiegend im Blot und den Kor iseigkeiton vor, Kaliam im 

ad in den geformten Elementen. Ober die Bedeutung des eee fir die 
‘om Muskel ond Nerv vgl. § 214.2, 242.2. Lithium konnte in 

in vielen Organon dos Kirpers nachgewieson werden (Herrmann™), 


edalkalion, Calciom ond Magnesiam finden sich als 

jangon in don Knochen. Aber auch in den Flissigkeiten und 

beiden Erdalkalion stets als lebenawichtige Bestandteile enthalton; in den mm 
in 100g frischer Substanz 0,01—0,02 g CaO und 0,02—0,04 9 Mg0 (. 
alzlosungon, die als Ernihrnngstitssigkeit fir tberlebende Organe dienen, 
tlze in einer bestimmten geringen Menge vorhanden sein (§ 38). 


« 
thwermetalle. Eisen kommt im Kirper wohl nur in organischer Bindang vor, 
auptsuche als Hamoglobin (§ 19), doch gibt os danebon wahrscheintich noch andere 
ge organischo Substanzen. Mangan scheint ebonfalls regelmiig im Korper vor- 
n. Kupfer, Zink, Blei, Quecksilbor sind zufallige Bestandteile; sie werden, 
inden Kérper gelangen, in der Leber abgelugert. Uber das Vorkommen von Kupfer 
tadinm im Blute niederer Tiere vel. § 15. 








Literatur (§ 5—9). 


0. Cohnheim: Chemie der Kiweiikirper. 3. Aufl. a raged 1911. Die yer 
venheimers Handb. J. Biochomio, Jena 1909, 1, 226. Proteine, in B. Abderhal- 
them. Handlexikon, Berlin beat y 4, 1. FL Hofmeister: %. P21, 1, 1902, 75% 
ts Bd, ch, G, $4, 1901, 8214. — 2, Fre N, Schule: Dio Grifle des BiweiBmolekils, 
& — 3. EB. Fischer: Untersuchungen her Aminosinren, Polypeptide und Proteine 
906). Berlin 1906. E. Abderhalden: Abban dor Proteine, in C. Op; 
Biochomic. Jena 1909, 1, 847, (Erweitertor Abdrnck: Nenere Engebnitwe anf dem 
der spexiclion Eiwoifichomie. Jenn 1909.) Polypeptide, Aminosiiuren, in A. Abder- 
Biochem, Handlexikon. Berlin 1911, 4, 211 0. 860. — 4. A. Gamgee, A. of 
¥. Jones: Wi. B.4, 1904, 1 und 10. — 5. FG. Hopkins u. 8. W. Cole: PLR. SB. 
— 6. T. B, Osborne: Die Pilanzenproteine. EB. P. 10, 1910, 47. Proteins d. Pilanzen- 
= Abderhaldens Biochem, Handlexikon, Berlin 1911, 4, 1. — 7. A. Schittenhetm 
Klooprotelde u. ihre Spaltprodukte, in C. Oppenheimers Handb, d. Biochemie, 
3 599. Nnklooproteide', Nukleinsiinton, Purinsubstanzen usw. in B. Abdem 
Biochom. Handloxike 1 Berlin 1911, 4, 9861. — 8. C. Oppenheimer: Die Fermente 
Wirkungen. 4. Aufl. Loipzig 1913. F.Samuely: Tierische Fermonte in C. Oppen= 
Handb. d. Biochem. 1, 1908, 501. H. Euler: B.P.6, 1907, 187. 9, 1910, 241. 
rnon: EB. P, 9, 1910, 188. — 9. F Ulser un. J. KTimont: Allgemeine und physio- 
Chomie der Fetto. 2. Ani. Berlin 1912. A. Jolles: Chemie der Fette vom 
‘isch -chemischen Standpunkte. 2. Anfl. Strafbarg 1912. W. Glikin: Chemie der 
poide o. Wachsarten, Leipzig 1912, Fette u. Lipoide, in C, Oppenheimers Handb. 
mie, Jona 1909, 1, 91. C. Brahm: Fette a. Wachse, in FE. Abderhaldena Bio- 
om Handlexik. Berlin 1911, 8, 1. — 10. A, Bémer: Zeitschr. f, Unters. d, Nahrangam. 
, 521, 25, 1913, B45. — 11. A. Windaus: Arch. d. Pharmacie, 246, 1908, 117, 
in E. Abderhaldens Biochem. Handloxik. Berlin 1911, 3, 268. — 12. J. Bang: 
1907, 131. 8, 1909, 463. Chemie u. Biochomie der Lipoide. Wiesbaden 1911. Phos- 
n_ &, Abderhaldens Biochem. Handlexik. Berlin 1911, 3, 225. ~ 13. £. 0. e. Lipp- 
Die Chemie der Zuckerarten. 3. Aufl. Braunschweig 1:4. C. Newberg: Kohle- 
in C. Le saree Handb. d. Biochomio. Jena 1909. 1, 159. Stiirke, Dextrine m:-w. 
dderhaldens Biochem. Handlexik. Berlin 1911, 2, 114M 2. Fischer: Unter- 
‘n jiber Kohlenhydrate nnd Fermente (1884—1908). Rerlin 1900. — 14. F. Somhlet> 
N, F. 21, 1880, 227, — 15. H. Landolt: Das optische Drehungsvermigen organischer 
Anil. Braanschwelz 1898. — 16. H. Rosin u. L, Laband: 0, m. W. 40, 1902, 
7, 1902, 182. — 17. C. Newberg n. H. Strauss: %. ph. 902, 


























. 45, 1905, 359. — 19. Girber u. Griinbaum: re 
. 905, 315. — 20. L. Langatein u. C.Neuderg: B.Z 4, 1907, 202. — 
rund: %. ph. Ch. 35, 1902, 111. — 22. Z. Gatin-Grusewska: P. AL 102, 1904, 580. 





[9] Literatur (§ 5—9), 








a rere miss, ‘Untersuchungen in der Betaig ys — 1906). Gat 
= Fe Dia or M8) 3, Te P= W. Engele: A-P. PBA, 





— 28, V. Wahlgren: A, 

; 1910, 60, — 30, R. Rosemann: B 

1911, 208, ir u. 459. — 31. A, Magnus-Leey: B. 2. 24, 

r Justus: V. A. 176, 1904, 1. 190, 1907, Lanetragtitig ee 
|. Nencki u. FE. O. Schoumow-Simai 

907, 414. 7, 1909, 2. 1 














40, 

tts) 1918, isa und 15, 157, 
1914, 1 42. J. Brandl u. HH. Tappeiner. 

1891, 518 — 43. Daring’ yon, 1896, 281. — 44. HH. Schulz: PA, 
555. 56, 1894, 203. — 45. Fr. N. Schulz: Z.a. P.5, 1905, 206. — 46. A. Gar 
129, 1899, 929. 130, 1900, 284. 134, 1902, 1894. 185, 1902, 812, 833. OC. r. w 
1902, 727. 56, 1903, 1242. Z. ph. Ch. 86, 1902, 391. — 47. G. Bertrand: 0. r. 
1481. 185, 1902, 800. — 48. K. Cerny: Z. pb. Oh. 84, 1901, 408 — 49. CE 
% phe Oh. 88, 1901, 329. — 50. B. Ziemke: V. x. M. (8), 28, 1902, 51. — 51. A. 

h, Ob. 44, 1905, 1. — 5% G. Bertrand w. H. Agulhon: C. x. 155, 1912, 
ia 3, 732 u, 2027, — 53, H. Schule: B.A. 84, 1901, 67. 89, 1902, 112, 181, 
144, 1912, 846 0. 850. — D4. E. Herrmann: P. A. 109, 1905, 26. 





th Gautier: O,r. soc. 


Physiologie des Blutes. 


10. Allgemeines iiber die Bedeutung des Blutes. 


tas Blut vermittelt die Bezichungen der einzelnen Organe des 
§ untereinander. In der Lunge und im Magendarmkanal (entweder 
oder indirekt durch die Chylusgefiife) nimmt es die fiir die Lebens- 
ge notwendigen Stoffe: Sauerstoff und Nahrungsstoffe auf und triigt 
( einzelnen Organen zu. Andrerseits nimmt es in den Organen die 
tfe des Stoffwechsels entstandenen Produkte auf und fihrt sie den 
eidungsorganen zu: Lunge, Haut, Niere. Zum Teil sind die in den 
en Organen entstandenen Produkte Endprodukte des Stoffweel 

ie weiteres zur Ausscheidung gelangen kinnen, zum Teil bedtirfen 
 zuvor noch weiterer Veriinderung; sie gelangen in letzterem Falle 
m Blute yon dem einen Organ, in welchem sie gebildet worden 
vuntichst in ein anderes Organ, in welchem sie erst in das zur 
eidung geeignete Stoffwechselendprodukt umgewandelt werden. So 
B. in den Organen entstandene CO, und NH, yom Blute zuntichst 
Leber gefiihrt, hier in Harnstoff umgewandelt, dann mit dem Blute 
Niere gefithrt und hier ausgeschieden. — Endlich kommt es auch 
6 in dem einen Organ gebildete Stoffe in einem anderen Or; 

je Funktionen auszatiben haben; auch hier wird die Obertragung 
das Blut bewerkstelligt. 

Jas Blut hat die bemerkenswerte Fithigkeit, trotz der vielen Ein- 
welche anf seine Zusammensetzung einwirken, sich hinsichtlich seiner 
edenen Higenschaften anniihernd konstant zu erhalten. Jede begin- 
Anderung in der normalen Zusammensetzung des Blutes bedingt 
eine erhohte Tiitigkeit der Ausscheidungsorgane, welche in ktirze- 
it wieder die normalen Verhiiltnisse zurtickfihren. Geniigt zeitweilig 
tigkeit der Ausscheidungsorgane nicht, um erheblichere Anderungen 
utes sofort auszugleichen, so tritt ein Austausch zwischen Blut und 
siltissigkeit in Kraft; abnorme Bestandteile des Blutes kinnen zeit- 
in die Gewebe abgeschoben, andrerseits Flissigkeit aus den Ge- 
in das Blut aufgenommen werden. Fiir die Konstanz der Blutzn- 
nsetzung ist endlich sehr wichtig die grofe Geschwindigkeit, mit 
8 Blut im Kirper bewegt wird: Stoffwechselprodukte, die im Lante 
Cages in betriichtlichen Mengen im Kérper gebildet werden, finden 
her in einem gegebenen Augenblicke oft nur in sehr geringer, eben 
sisbarer Menge im Blute, da es bei dem schnellen Transport zu den 
eidungsorganen niemals zu einer Anhiiufung derselben im Blute 


[§11.] Physikalische Eigenschaften dex Blutes. Farbe. Spezifisches Gewicht, 


kommen kann. So wird es auch begreiflich, da6 die Unterschied 
Zusammensetzung des zu einem Organe hinstrémenden arteriellen 
abfliebenden yendsen Blutes, die nattirlich vorhanden sein miisse 
so klein sind, da sie sich “der Erkenntnis entziehen. 


Unter pathologischen Verhiltnigsen ma natiirlich entsprechend der 
Titigksit der Organe auch die Zusammensetwung des Blutes geiindert sein; aus 
angeftihrien Griinden ist aber in den moisten Fiillen auch hier die Anderang 1 
figie. Erhebliche Andorangen der Eigenschaften des Blates, Anhiufung krankhafte 
in demselben usw. kommen erst bei schweren Storangen der normalen Vorhii 
Boobachtang. 


11. Physikalische Kigenschaften des Blutes. 


1. Die Farbe — des Blutes weehselt von hellem Schar 
in den Arterien bis zum tiefsten Dunkelrot in den Venen. ( 
auch die Luft) macht es hellrot, O-Mangel dunkel. (CO, wirkt nicl 
Farbe des Blutes ci — Das O-freie Blut ist dichroitisch, d. 
scheint bei auffallendem Lichte dunkelrot, bei durchfallendem 

Die Farbe des Blutes rithrt her von den in der farblosen 
keit schwimmenden roten Blutkérperchen, welche den Biuttt 
oder das Hiimoglobin in sich enthalten. Der Farbstoff des I 
also nicht im Blute in Lisung vorhanden, sondern in Form kleine 
licher Teilehen in der Fitissigkeit suspendiert; dies bewirkt, 
Blut auch in diinnen Schiehten (wenn man es z.B. auf einer ( 
ausbreitet) undurchsichtig oder ,deckfarbig“ ist. Durch ei 
verschiedenartiger Kinwirkungen (vgl.§ 14), am einfachsten dure 
yon destilliertem Wasser zum Blut, kann man bewirken, dab der 
stoff aus den Blutkérperchen austritt und in der Blutfltissigkeit sich 
das Blut wird dann durchsichtig oder ,lackfarbig*. 


Nach Koeppe! ist dax deckfarbige Anssohon des Blatos dadurch boding 
Wand der roten Blatkirperchen aus einem fettartigen Stoff bestabt und dieser, 
suspendiert, wegen der yerschiodenon Lichtbrechang das Wasser undurchsicl 
Wird Bint in sehr sehnoll rotisrenden Zentrituzen (liber 5000 Umdrebungen in « 
zontrifngiort, so dal dio Blntkorperchen ohne jedon Rost von Zwischontli 
aneinander gopreBt werden, so erscheint die Blutkirperchensinle lnckfarbig; ° 
Blatkirporchen wiedor im Plasma verteilt, so orscheint das Blut wieder deckfurl 

Worden dio roten Blutkirperchen zum starken Einschrampfon gebracht, 
Voermischang des Blutos mit konzentrierton Sulzlisungen, so wird die Farbe 
scharlachrot, holler als jemals in den Artorion, Boim Vermischen mit Wasser wi 
dio Farbo des Blutos dunkol, 


2. Das spezifische Gewicht des Blutes — betriigt bei 
1055—1L060, bei Frauen 1050—1056. Das spezifische Gewicht 4 
Blutkérperchen ist LO80—1089, das des Plasmas (und des 
1027—1030; hieraus erklitrt sich die Neigung der roten Blutkd; 
sich zu senken. 


Methode der Bestimmung. — 1, Nach Schmalts". Bin Glasrihrehar 
pyknometer) von 10mm innerem Durchmesser und 12.¢m Linge mit verengten Ei 
dor Inhalt gat anriickgehalten werden kann, wird erst leer, dann mit destilliorte 
dann mit Blut gefillt gewogen. Das Gewieht des Blntes dividiort durch das G 
Wassers gibt das spex. Gewicht des Ilutes. (Eine zweckmilBige Modifikation der Sch 
Capillaren geben Loeicy u.v. Sehrotter? an.) — 2. Nach Hanunerschlag*. Ein 
des zn untersuchenden Blutes bringt man in eine Mischung yon Benzol (spex. Ge 
und Chloroform (spez. Gewicht 1,49), welche annihernd dasselbe spez. Gewicht w 
hat, Je nachdem der Blutstropfon in der Mischung steigt oder fallt, figt man tt 
Benzol oder Chloroform bingy, bis der Blatstropfen in der Mischung schwebt, un 


Landois-Rogemann, Physiologie. 14. Aufl, 








ingegen gallensant Contractionen pers 
oz. Gewicht durch ‘Austritt ‘yon Fifissigkeit ang dem Blute, ah pokeheb aiken 
ren (E. Grawits"), (Vel. das jende Verhalten der Zabl der roten Blutkirper 
i Blotdruckschwankungen, pag, 38,) | 


3. Die Reaktion, ~ 


Physikalisch-chemisebe Vide Cia telal Los Die Reaktion ¢iner 
dnreh an Wasserstoffionen H, welche saure Reaktion 


und Basen 
42), 
o & BR 
m Grade der 





sind ebenfalls die H,O-Molekiile, allerdings nur sa einem auBlerordentiichs 
in H: und OH-Ionen gespalten; Wasser kann daher 20 gleicher Zeit als eine 
(eh schwache Siiure, ‘Tesp. Baso anfgefabt werden. Wird aise Phare derek: 


ten OH-lonén gebunden, in der Fiissigkeit also wedor freie H- noch Oli-Ionen yor 
sind (riehtiger: wenn sur noch so viele freie H- und OH-lonen vorhanden sind, 
reinem Wasser). Die Reaktion einer Flitissigkeit kann gemessen werden mur 
Methodem, welche don Gehalt der Fifissigkeit an H- resp. Of-lonen anwer 
$ Inasem: es ist das durch physikalisch-chemische Methoden (Kenzentral 
taf die hler nicht other eingogangen werden kann, ansfihrbar, Bel der ‘Titration 
pene der Ionengebalt nicht unyorindert. Wird 2. B. cine schwache Sliure, etwa 
G,H,0,, deren Molekiile also nur zu cinom goringen Teile in ihre Tonen H und 
{ sind, mit Natronlange titricrt, so binden die OH-lonen der Natronlange 
ft die vorbandenen freien H-lonen der Essigsiurc. Durch diesen Verbranch freier 
t-wird aber das Gleichgewicht, welches zwischen dem dissoziierten und dem nicht 
ertes Axtell der Hssigsiiure besteht, gestort und os xerfallen weitere Exsigeiure 
le; die dabei frei werdenden H-lonen werden wieder gebunden derch OH-lonen and 
+ bis alle vorbandene Essigsinre gespalten und alle H-lonen, die die Essiguiiure 
kounte, gebunden sind. Bol der Titration wird also nicht der Gehalt der Fiitasigket 
gublicklich im freien Zustand vorhandenes H-lonen (aktuollo lonon) festmestellt, 
( anBerdem anch die Menge der H-lonon, wolche die Flissigkeit bei Zasatz yon Alkali 
stralisation abspalten kann (aktuelle and potentielle lomen). So kommt ea, 
dor Titration eine schwache und cine starke Shure gleichviel Natrontauge verbraneht, 


Das Blut ist cine fast vollig genau neutrale Fitissigkeit. Der Ge- 
les frischen, defibrinierten Stiugetierblutes an Wasserstoffionen wurde 
t Messung mittelst Konzentrationsketten, v; gl. die Originalarbeiten) za 
1,7.10—7g-Aquivalent pro Liter gefunden (Hiber "', Fraenckel *, Farkas **, 
idler *, Szrili®, Hasselbulch u. Lundsgaard 4, Michaelis u. Davidojf*®, 
*); das ist fast derselbe Wert, wie die W: asserstoffionenkonzen— 
1 im reinen Wasser (0,8.10—*). — Ebenso wie das Blut verhilt sich 
‘utseram and die Gewebssiifte. 


lat) Reaktion des Blutes, 


Die Reaktion des Blutes wurde bis vor kurzem allgemein f) 
lisch geraltem anf Grund des Verhaltens gegentiber Lackmus 
man einem Yropfen Blut (noch besser einen Tropfen einer Misch 
gleichen Veilen Blut und konzentrierter Natriumsulfatlisung) auf 
liches fliederfarbenes Lackmuspapier und saugt pee den Bly 
dessen Eigenfarbe die Erkennung der Reaktion verhindert, mit F) 
fort, so hinterbleibt auf dem Lackmuspapier cin blauer Fleck. 
ist aber selbst cine mittelstarke Siiure, es treibt die Kohlensiiure « 
Verbindungen aus und ist also zur Untersuchung der Reaktion von 
keiten, die Carbonate enthalten, wie das Blut, ungeeignet. Unters! 
Blutserum mit kohlensiureempfindlichen Indicatoren, wie z, B 
phthalein, so erweist sich die Reaktion, in Obercinstimmung 
oben erwihnten Untersuchungen, als genau neutral (Mried 
J. H. Schultz **). 

Das Blut hat die Fuhigkeit, eine bestimmte Menge von Si 
zanehmen, ehe es anfiingt, sauer zu reagieren, und zwar infol; 
Gehaltes an Carbonaten (Mononatriumearbonat) und Eiweib, welcl 
falls Stiure za binden vermag. Durch Titration mit einer Siiure | 
Grobe dieses ,Stiurebindungsvermigens* bestimmt werden; 
haltenen Wert, auggedrtickt durch die Zabl von mg NaOH, dene 
Blut iiquivalent sind, bezeichnet man als (Titrations-)Alkalese 
Blutes. 


Quantitative Bestimmang der Alkalescenz des Blutes. 1. Titration 
farbigen Blutes. Man titriert oin bestimmtos Volumen Blut mit .j-Norms 
(1 em*=4 mg NuOW), bis blanes Lackmuspapicr sich rétet. Um dio Bestimmung 
Blutmengen ausfihren zn kiinnen, verfiihrt man nach Landois-v.Jakech*® folger 
Man bereitet sich eine Anzahl yon Weinsiurelisungen abnehmender Aciditit, 
1: 0,9¢m? yy Normalweinsiinrs + 0,lem® konz, Natrinmsolfatlisung; Losnng 
hy Normalweinsiare >-0,2 om? kon, Natrinmsalfatlisung and so weiter bis Lisang 
ub Normalweinsiinre + 0,9 em* konz, Natriamsulfatlisang; forner Ldisung 10:0, 
Normatwoinsiiure + O,lem* konz. Natriumsulfatlisung bis Lisung 18:0,1 em? py 
weinsinre + 0,9 cm* konz. Natrinmsnifutlisung. Mit cinor Capillarpipette ontn: 
cin genau gemessenes Quantum Bint, x. B. 0.1m? und setzt es der Reiho nach = 
der obigen Lisungen, mixcht nnd. priift dio Reaktion mit Lackmuspapier. 
diejenige Weinsiurelisung, welche das Blat gorndo noutralisiert, und bereehnet 
Alkalesconz des Blutes. — 100 cm? Menschenblut haben nach dieser Methods eit 
con entsprechend 260—00 mg NaOH (¢. Jaksch*), 

2, Titration des lackfarbigen Blutes, — Loewy" empfiohit, daa B) 
‘Titration lackfarbig au machen, ao daf der Inhalt der roten Blatkirperchen, de 
der Titration dockfarbigen Blates in unberechenbarer Weise an der Reaktion bot 
vornhercin an der Reaktion teiInimmt; die Bestimmung ist dann von dee Tomy 
abbiingig und Mit sich schneller ond sicherer ansfihren. In cin S0em? fussendos 
dessen Hnls zwischen 49,5 und 50,5 in yy cm? goteilt ist, gibt man 45 cm 0, 
von oxalsaurem Ammon, welche die Gerinnung yerhitet und die Blntkirperch, 
und ca. dem? Blut; die genius Menge, die verwendet worden ist, liest man a 
dvierang ab. Nach der Mischnng titriert man mit y'5 Normalweinsiure unter V 
von Lackmoldpapier. — Loesy® fand auch dieser Methode die Alkaleseenz vc 
Menschonblat = 447—508 mg NaQH; StrawfZ** dagegen nach dersalben Me 
= 300—350 mg NaOH, 


Das Blut hiilt seine neutrale Reaktion im lebenden Kirj 
es scheint, unter allen Umstiinden aufrecht. Werden in den Kérpe 
cingeftihrt oder entstehen solche im Stoffwechse) (unter pathologise 
hiltnissen oft in grofer Menge, 2. B. Acetessigsiiure, Oxybuttersit 
Diabetes, vgl. $ 168), so werden sie abneutralisiert, entweder durch 
an NH, welches aus dem Eiweibstoftwechsel stets zur Verfligung st 
indem eine gewisse Menge CO, aus den Carbonaten des Blutes anss 


Keaktion dos Bintes. Die roten Blutkieperchen, 


Andrerseits werden in den Organismus eingeflthrte Alkalien di 

‘ts reichlich vorhandene Kohlensiiure neutralisiert. Wenn 

lieser regulatorischen Kinrichtungen die Reaktion des Blutes 

an aktuellen H- und OH-Ionen) stets anniihernd unveriindert b 

tn dabei doch die Titrationsalkalescenz (das Vi 

den, durch Abgabe weiterer potentieller OH-lonen) schwank: 

tm die siurebindenden Valenzen des Blutes bereits anderweitig: 

reniger in Anspruch genommen sind. Die Titrationsalkaleseenz 

unter physiologischen Verhiiltnissen Schwankungen nach oben 

(bis um ed Na OH flr 100cm® Blut; Straus*). Durch 

ltitigkeit wird sie infolge der Stiurebildung im Muskelgewebe ver- — 
(Cohnstein®), Kinder und Frauen haben eine geringere Alkalescenz 
inner, Wiehnerinnen eine geringere als Schwangere (Jacob?*), Ver- 
le vine stiirkere als Ntichterne (Peiper™), — Nach dem Austritt aus— 
ler nimmt die Titrationsulkalescenz bis zur yollendeten Gerinnang 
snsitiit ab, und zwar um so schneller, je gréber die Alkalescenz war. 3 
eruht auf einer Siurebildung, an welcher die roten Blutki: en 
einer noch unerforschten Zersetzung beteiligt sind. Héhere Temperatur 
Ikalizusatz befirdern diese Sturebildung (N. Zuntz**). Altes, oder 
asser aus trockenen Stellen aufgelistes Blut reagiert meist sauer. " 





tathologtaches. Auch onter pathologischen Verhliltaissan hat sich dle Reaktion 
‘os (der Gebalt an aktuellen H- und O1-Io: den bisher untersuchten Fallen als 
id nontral erwieron, xo bei Diabates (Benedict*), Nerven- und Geistoskranken, imi 
chen Anfall (J. H. Sehultz"*), — Dagogon xcigt die Titrationsalkaleseenz unter 
ischon Verhiilinissen Schwankungen nach oben und ater. Im Coma diabetionm 
bine sobr starke Erniedrigung der Alkalescons (Magnus-Levy"), Gifle, welchs einen 
‘olor Blutkirporehon bewirkon, vermindern gleichfulls dio Alknlesconz (Krams ™*). 


» Der Gofrierpunkt des Blutes — liegt bei — 0,56°C (Kord- 
Vgl. § 13. 


+ Blut but cinon eigentimlichon Geruch, der bei Menschen und Toren verschioden 
soll auf dor Gegenwart fliichtiger Fettsiuren beruhon. — Der salinische 
awek des Mates rhhrt her von den in der Blotilissigksit vorhandenen Salzen, 

thor die Visoositdt dos Blutes vgh § 48, fiber den Refraktionskoeffi- 
1528, 







12. Die Formelemente des Blutes. 


. Die roten Blutkérperchen oder Erythrocyten (Fig. 2 u. 2a) — 
t beim Menschen 1673 von Leenwenhoek, beim Frosche 1658 von 
werdam entdeckt, 
fenschliche rote Blutkirperchen sind miinzenférmige Scheiben mit 
witiger tellerférmiger Aushéhlung und abgerundetem Rande. Sie sind 
von gelblicher Farbe und cinem Stich ins Griinliche. Sie besitzen 
4 Skugetioren keinen Kern; dieser verschwindet bei der Entwick- 
er roten Blutkérperchen aus den kernhaltigen Erythroblasten (§ 16). 
orhandensein einer Hllle wurde frither fast allgemein bestritten, 
ber nenerdings wieder mehrfach behauptet (Deetjen®*, Weidenreich ™, 
1, Albrecht™*, Lihner®, Schilling®). Sie bestehen — 1. aus einer 
itsubstanz, cinom fuberst blassen, weichen Protoplasma: dem 
ia und — 2. aus dem roten Blutfarbstoff, dem Himoglobin, 
r in dem Stroma durch besondere Kriifte in nicht nuher Dae 
fixiert ist. 


($12) Die roten BIUKOF percha, 


Das Hiimoglobin kann in den roten BlatkGrperchen nicht in geliist 
vorhanden sein: da die roten Blutkirperchen 32,05! Winogiobia, und 63,2 
enthalten, wiirde eine 33,65"/,ige Hiimoglobintisone ; sine solobs kan. 
bestehen wegen der geringeren Lislichkeit des Hiimoglobins (Hollett™*), 

Nach Weidewreich*™ soll die normale Form der roten Blutki de 
atout die bikonkave Scheibe, sondern eine konvex-konkave sein. 

ner, 


Der Durehmesser der roten Blutkirperchen des Mensche 
7.9 p, die Randdicke 25 », die dinne Mitte 1,8—2 » (Fig. 2) 


Fig 2 Fig. 2a. 





A Rote Bhatkirpereher 
— £ goldroilenat 









ntebens I von der Fikehe, — 2 on dor Ka 
anderlagerung der roten TMutkOrperchen, — 











lor 
cines roton Blutkorperehous yom Monseben bel 6000facher Jinearer 
mossor, ¢ d gedbite (Rand) Dicks. — Fig, 20. Ms 

korperchen, dazwitcben 


Bei Gesunden schwankt der Durchmesser yon (—9y; die Durchs 
=72-7,8~. — Verkleinert werden die Korperchen durch Hunger, erhi 
wiirme, O04, Morphinm, — yorgrifert durch ©, Wiisseriekeit dea Blutes, Kill 
genuB, Ohinin, Blausiure (Manassein™), (Pathologische Verhiltnisse vgl. § 18.) 

Das Volumen — eines Erythrocyten betrigt 0,000000072217 mm’, die 0 
0,000128 mm®, Nimmt man die Gesamtblatmasse des Menschen 2n 4400 em? 9 
simtliche darin enthaltone Blatkirperchea eine Oberiliche von 28160, d. i. 
Quadratiliiche yon 80 Schritt in der Seite (Weleker™). — Dus Volumen 
kirporchen im Verhiltnis zum Plasma kann man bestimmen, indem 
vermischt mit gleichen Toilen gerinnngshanmender konservierender Flissig 
Kochsalz +} 0,1% Nutrinmoxalat), oder anvermischtes Blut in mit Ol fiberzoge 
in einem dfinnen graduierten Glardhrehen (Himatokrit) zentrifgiert (Hedin ®, 
Hedin® fand das Volumen dor Blatkirperchen bei Minnern zu 42, bei Franc 
bei aniimischen Personen sind die Werte viel geringer. Mit sehr schnell rotie 
fugen (Aber 5000 Umdrobungen in der Minnte) kann man frisches Blut ob 
xentrifugieron, bevor Gerinnung eintritt; die Blotkirperchen worden dabei so 
godrickt, da auch der Iotzte Rest von Plasma xwischen ihnen entfernt wire 
korperchensiinle erschoint lackfarbig, vgl. pag. 33); es wird dann algo das absob 
der roten Blntkiirporchon gemossen (Koeppe*). Venisex Bint hat ein gréferes Vol 
Erythrocyton als arterielles (Hamburger). 


Miinner haben im Durchschnitt 5 Millionen, Frauen 4°5 Milli 
Blutkirperchen in 1 mm, in der gesamten Blutmasse (ca. 5? | 
25 Billionen, Die Zahl steht im umgekehrten Verhiiltnis zur M 
Plasmas, woraus sich ergibt, dab je nach den Contractionszusti 

































Die roten Blutkorperchwen, 
st Druckverhiiltnissen, Diffusionsstrémungen u. dgl. die 4 


Nie Zahl dor roten Korperchen ist vermehrt: in vendsem Blute (zamal 
en ond Stanangon), nach Aufnahme fester Nahrang, nach der Nachtrohe., 
Wi ibe durch die Haut, den Darm oder dio Nieren, wahrend des 
dos Verbranches des Blutplasmas), im Blute des Neugeborenon (Z 
, bei kriiftigen Konstitutionen. — Vermindert ist die Zahl; in der 8 
nach, ‘Trinken. B i 


Fliissigkeitsabgabe 
ne Vermehrang der Zahl der Blatkorperchen (zugleich Vermebrang dex H 
des spozifisels und Sen 
entsprechonde 
fethode der Blutkirperchenzlihlung (Barker*). — Zunichst wird das 
200fich verdiinnt, Rine exakt kulibriorte Glaspipette (Fig. 4) wird mit der § 





Fig. & Fig 
A 





t 





lutkorperchen-ZAblapparat von Abbe-Zeiss: A im Quer 
1, © von dor Fiteho gosehen, 1 das mikroskopisebe Die Mischpipetee. 
Bild mit den HtutkGrperchen. 


‘nt getancht und durch Sangen an dem Kantschnkschlanche f° wird das Bint bis eu 
ce 4/, oder bis zn der Marke Z anfgesaugt, Sodann bringt man die (abgewisehte) 
B°/ige Kochsalelisung und saugt diese anf bis zur Marke 107, Durch Schwenken 
ite wird eine Kleine Kugel (a) in dom bauchigen Hohlranme umbergeschlendert und Fd 
itnommene Blutprobe gleichmiBig mit der Vordinnungsflissigkeit gemiseht. Je mach 
Blut bis ar Marke '/, oder J anfgesogen war, hat man eine Verdiinnung von 
der 1100. 


un gibt man ei 


‘Troptchen der Mischang (die ersten Tripfchen worden yorworfen) in die 
mmor (Fi eine anf einen Objekttriger gvkittete, mit einem Deckglase ga fiber 

5 Q.tmm tiefe Glaszelto, deren Boden in Quadrate geteilt ist. Dor Ranm Ober einem 
adnate ist = /jy9m. Man xihlt die Blutkirperchen unter dem Mikroskope im 
iBeren Anzahl vou Quadraten und berechnet daraus den Mittelwert fir cin Quad 
ltiplikation dieser Zahl erst mit 4000 und dann je nach der vorgenommenen Ver 








peasy aur row oERUTperenent. 


dannong mit 100 resp. 200 erhilt man die Zahl der Blutkirperchen in Dann! 
dinnten Blutes. Kine achr zweckmaGige Form der Zihikammer, welche die Fehler 
Kammern yermeidet, sowie andere V¢ der Methode hat Biirker™ 

Zor Ziiblung der weiBen Blutkérperchen yerdinnt man das Blot 
und zwar mit einer '/,°/igen Essigsiiuremischung, durch welche die roten Bly 
anfgelist werden. Zur Firbung der weiben Blutkirperchen sett man dee Flt 
Spur Methylviolett hinza, 


Die roten Blutkérperchen zeichnen sich durch grobe Eli 
Biegsamkeit und Weichheit aus. Sie kénnen info! ( 
deren Durchmesser Kleiner ist als der eines roten Blutkirperche 
Forminderung passieren. p 

Blutkérperchen erhalten in entleertem und sogar defibrinier 
wenn es wieder in den Kreislauf zuriickgebracht wird, ihre Le 
Funktionsfihigkeit ungeschwieht. Wird Blot aber bis gegen 
wiirmt, so ist die Lebensftihigkeit der Erythrocyten erloschen; 
solchen Blute lésen sich, wenn es in den Kreislauf zurtickgebri 
schnell alle Blatkérperchen auf. — Kalt aufbewahrt kann Sit 
4—5 Tage Jang sich fanktionsfithig erhalten, 

In frisch entleertem Blut legen sich hiiufig die Blutkérpercl 
rollenartig aneinander (Fig. 2, A. 3). 





Rote Blutkorporohen in vereehiedenon Formverinderangen und Auflosungescadion: 

Anderte rote MatkOrperchen vom Menschen bel verechiedener Kinstollung dos Te 

rehdesel emi ‘worren der vorschiedonen Kinstellan lon 

© de sogeoannt 1 9h ,Stochapfol- oder Morgenstarnform®; 4 ¢ .Ku 

kabgeblallte Ki {durch toilwoiso Wasservntziohung faltig gosehrumy 
BluthOrperchon vom Frosche. 





Nach der Entleerung aus dem Korper bewirken schiidig 
fitisse, die auf die roten Blutkérperchen einwirken, besonders Flt 
von anderem osmotischen Druck wie das Blatplasma (§ 13), leicht ¢ 
vertinderungen der Blatkérperchen. Manche Einwirkungen brin 
Reihe yon Formyeriindernngen schnell hintereinander hervor. Lubt 
die Punken einer Leydener Flasche das Blut treffen, so wert 
alle Blutkérperchen ,maulbeerférmig*, d.h. die Oberfliiche 
und mit gréferen und kleineren randlichen Héckern besetzt (Fig 
Weiterhin werden die Blutkérperchen fast kugelig mit viele) 
ragenden Spitzen, ,stechapfelférmig” (gh). Alsdann nel 
Korperchen villige ,Kugelform* an (#i). In dieser Gestalt ersel 
Kleiner als die normalen, da sich ihre scheibenformige Masse 
Kugel von kleinerem Durchmesser zusummenzicht. Endlich trenni 
Blutfarbstoff yon dem Stroma (k), die Blutfliissigkeit rétet sich, 





Osmotischer Druck. Gefrierpu mktserniedrigung. 


oma nur als leichter Schatten erkennbar ist (2). 
r lackfarbig geworden. 
twiirmt man auf einem heizbaren Objekttische ein 
ea awiscen 6 und GO di Blak en eigenarti; 
gen. Sie werden teils kugelig, teils biskuitftirmig 

is Pratenies durehlichert, oder es schniiren sich griGere und klei: 
en der Kérpersubstanz vollstiindig ab und schwimmen in der 
on Fllissigkelt (Max Schultze*). Bei Erwirmung auf pir 
5—20 Minuten lisen sich endlich die Revdineried villig auf. 

imungen kinnen die Blutkérperchen innerhalb der Gefabe dieselben 
orungen erfahren (vgl. § 18. 2). 
uw Konserviernng der roten Blutkiirperchen dienen: 1. Pacinia Fre | 
rr bichlorat. 2. Natr. chlorat, 4. Glycerin. 26. Aq. destill. 226. Vor der Anwendung 
Jen destillierten Wassers a verdtinnen. 

iene Fitissigkeit: Hydrargyr. biehlorat. 0,5. Natr. sulfuric. 6. Nate. ehlorat. 1. 







‘. Osmotischer Druck. Elektrolytische Dissoziation. 
ie (Hyper- und Hypisotonie). Permeabilitit der Erythroeyten.*® 


smotischer Druck. Wenn in cinem GefiB cine Lisang irgend einer Substanz 
sreuckerlésung) mit destilliertem Wasser vorsichtig Oberschichtet wird, so daS a 
tung der beiden Fitssigkeiten statttindet, so wandern die ‘Toilchen dor gekiaten Sub- 
) Rohraucker-Molekile) — der Wirkung der Schwere entgegen — allmihtich in das 
to Wasser empor, bis sine vollig gleichmiSige Vermischung eingetreten ist (Diffmsion). 
beiden Flissigkeiten durch eine Membran voneinander getrennt, so hiingt das weitere 
1 von den Rigenschaften dieser Membran ab, Ist aie fiir das Liisungsmittel (Wasser) 
geliste Substane (Rohravcker) villig undurchgingig, so kiinnen die beiden Fliissig~ 
WOrlich Gberhanpt in keine Bexiehung xueinander treten, Ist die Membran fiir das 
nittel und die goliste Substanx in gleichem Mafe durchginglg, so tritt natiirlich 
ein so, als ob keine Membran vorhanden wire. Es kann non aber drittens die 
halbdurchlissig (semipermoabol) sein, d. bh. durchlisslg fir dus 
Vasser), aber undurchlassig fiir den geliisten Kirper (Rohrzucker). (Derartige Mem- 
Wnnen kiinstlich hergestellt werden; sie kommen anferdem im Ptlanzen- und Tier 
t.) In diesem Falle werden die Molekiile des gelosten Kirpers ebenfalls das Bestreben 
1 das destillierte Wasser einzadringen, aber anf ihrem Wege dahin werden sie durch 
bran, die ja fir sie undurchgingig ist, anfgehalten, Sie werden daher einen Druck 
Membran ansiiben, und diesen Druck nennt man den osmotischen Druck. 


vefrierpunktserniedrigung. Der osmotische Drack einer Losung kann direkt 
+ werden in einer Weise, deren Beschreibung hier xu welt fihren wiirde. Indirekt 
gemessen durch die Bestimmung der Gefriorpunktsorniedrigung. Man yer 
er Gofriorpunktserniedrigung die Differenz zwischen dem Gofrierpunkt der zu unter- 
Tsung und dom Gefrierpunkt des destillierten Wassore und bexeichnet diesen 
t 4. Die Gofrierpunktserniedrigung ist dem osmotischea Druck dirokt 

m aus derselbon den osmotischen Drack berechnen. Hiufig fihrt man diese Um: 
t aber gar nicht aus, sondern gebraucht die Gofrierpunktserniedrigang selbst als 
& fir die GroBe des osmotischen Drnekes. 

fie Bestimmung yon S erfolgt mit dem Beckmannschen Gefrierpunkts-Be- 
ingsapparat (Fig. 6). Derselbe besteht aus einom Kahigefa zur Anfnahme 
Mtemischung (Bis und Kochsalz), —— einem in dio Kiltemischung eiutazehenden 
‘obr, welcbes als Luftmante! dient und in welchem sich, rings von Luft smguben, 
Gofrierrohr mit der xu untersuchenden Flissigkeit befindet. In die Fifissigkeit 
in Ribrer zum Umrihren und ein in '/,95° geteiltes Heckmannsches Thermometer, 





if 
ligt an seinom oberen Ende ein (uecksilber-Reservoir; man kann mit Hilfe desselbem 
Thermometer sellist befindliche Quecksilbermenge verindarn und so das Thermometer 
b woiterer Tomperaturgronzen benntzen.) Zur Anefiihrang dor Bostimmang gibt mam 
intorsnchende Flissigkeit in das Gefrierrobr, sotzt Rohrer und Thermometer éin und 





(313) Usmotischer Druck. Gefrierpunktsormedrigung. 


vorsenkt 8 zuniehst direkt in die Kiiltamischung, Man kibit unter fortwithrend 
bis in die Nihe des xu erwartenden Gefrierpunktes ab und versotzt dann das Ge) 
den pees dor eine langsame, vollig gleichmaBige Abkablang ormdglicht. 
Ribron sinkt die Tomperator der Fiissigkeit nun zunlichst unter 

penn ohne da die Flissigkeit cay ae Eeoeney Entweder yon selbst 
inimpfang eines kleinen Eiskrystalls in die Fitissigkeit (durch das am Gefrierr 
angebrachta Ansatarohr) tritt dann plitzlich cine Ausscheidung von Riskrystallen 
steigt das Thermometer auf den Gefrierpunkt und bleibt anf diesem Pankt oi 
atehon, Die Differs 


Fig. 6. 


sind eine Reihe yo 
maBrogaln zu be 
Vemperatur der 
schung soll nur 
stets um densell 
unter dem au ¢ 
Gefrierpunkt liog 
torkiihlung dart 
and maf bei jede 
gleich sein; das) 
miglichst gleichn 
q gen; vor der Ab 
das = Thormome} 
Klopfen erschiitt: 
Prixisionsapparat 
sehr grofe Gena 
Bestimmangermd 
von Nernst 1, 
Raoult angogobs 
Van't Ho, 

1887 das Gosety 
osmotische Dy 
stiindig dem ¢ 


gleich gesetz 

Apparat eur Gefrierpunkstbestimmung nach Beckmann. Daneben i 
dar cbere Ende des Thermometers tin vorgroBerten MaGatabe. KANN; in gelost 
halt sich in einer 


cin Gas. Ein in einem bestimmten Raumtaile Wasser gelister Stoff bt. densi 
tischen Druck ana, den er als Gaadruck ausiben wirde, wenn er bei Abwe 
Wassors den gleichen Raum im gasftrmigen Zastande orftllte, Dio Gasgosets: 
leichen Sinne anch fir don oamotischon Druck, Wie nach dom Mariotteschen 
Konstanter Tomperatar dar Druck eines Gases der Dichtigkeit desselben proporti 
ist der omotischo Druck einer Liiwung bei konstunter Tomperatur der Konz 
dorselben proportional, d. h. cine 2-, $-, de naw. *),igo Losung eines Stoffes hut dei 
dreifuchon, vierfuchon usw. osmotischen Druck (und ebenso die doppelte, dreifach 
usw. Gofierpenktaernodriguns) wie vine I¢higo Tamang deseelben Stas, Gx 
nach dem Gay-Luesacachon Gosetz der Gasdrack, wilchst auch der oamotischt 
Erhibung der Temperutar am je 1° nm “fy des Drackes bel O*. Und schliedl 
nach der Avogadroschen Regel der Gasdruck, so auch der osmotische Druck un 
von dor Natur der gelisten Substanx und allen bodingt von dor Zahl der | 
befindlichen Molekile, Let man dahor von verschiedenen Stoffon Jodesi 
Gramm, ala dem Molokolargewicht entapricht, odor oin ,Mol* (x. B. 342y' Rohr 
609 Harostott) in demeotben Volumen Wasser auf, #0 haben disse Losunge 
osmotischen Druck (nnd donselbon Geftierpnnkt). Aquimolekulare Lisung 
denselben osmotischon Druck (und douselben Gofrierpunkt). Die 
Losung eines Stoffos, wolche in 1 Liter Wasser 1 Mol dos Stoffes onthilt, hat — 
von der Natur des Stoftes (bei Flektrolyten ist allerdings die Dissoziation xa beri 


Rikres fer die» 
Raltemischung 














Sreshonpt kanm in merklicher Weise. 


eal dena! Dissoziation. Kine Ausnahme yo dem zuletet angefGhrten 

om xuniichst die wilsserigen Lésungen der Sinren, Basen und Sales xm 

fohe Druck certaenpen dieser Stoffe ist nimlich viel hober, als sich nach 
set wiirde. Dioses Verhalten orklirt sich aber auf Grund der von 


Jctronegative CHonen, Na, CO, in clektropositive Na-Ionen und ek 
dissoziiert. Je ie ptigin Cerin am so mehr sind die Molekiile 

in ihre Tonen dissoxiiert. Die nicht diseoziierten Molekiile sind bei der 
schen Stromes nicht beteiligt; daher Ieiten Ligungen von Rohreacker, Harnstoff asw., 
bei der Léisang keine Zerlegung in Ionen erfahren, den elektrischen Strom ae 
sitang des alektrischen Stromes erfolgt nur durch die Ionen and geschieht mm 
+ Je mehr Tonen in dor Fitssigkeit vorhanden sind. Die Bestimmung dor aia 
ren Leitfahigkeit einer Lisung gibt daher MaB der 

tdenen dissoziierten Ionen. Die Ionen verhalten sich nun hinsichtlich des 
tixchen Drucken wic Molekile Lost man daher 2. B. 58,59 (das Molekuber 
it) NaCl in 1¢ Wasser, so hat dic Flissigkeit nicht denselben osmotixchen Drack 
Gefrierpunkt) wie etwa cine HarnstoMisang von GOg Harnstoff im Liter, sondern 
ee ; denn bei dieser Konzentration sind fast alle Kochsalzmotektile in die 

ert. 

An lebenden Zellon hat znerst de Vriew (1884) ommotische Erscheinungen be 
ot, and xwar an Pflanzenzellen. Die Membran der Pflanzenzellen ist flr Wasser und 
durchgiingig, die der Membran anliegende Protoplasmaschicht nur fiir Wnsker, nicht 
ilze, Bringt man nun Pflanzenzellen in destilliertes Wasser oder stark werdiinnte 
angen, so ist der oxmotische Drack im Innern der Pilanzenzelle stirker; die Zelle 
unter gleichaeitigem Kintritt yon Wasser in dieselbe. Bringt man die Zelle dageges 
wontriorte Salzlisungen, so ist der osmotische Druck dieser Salzkisungen gréBer als 
dor Zelle; die Zelle schrampf daher unter gleichzeitigem Austritt yon Waswer ams 
den, dor Zellelb xloht sich dabel von der Membran xarfick: Plasmoly: Je konzen- 
fr die Salzlosung ist, um so stirker ist natOrlich die Plasmolyse. Bostimmt man fiir 
indene Salztiicungen dinjonige Konzentration, welcha gerade die orsten Zelehen dar 
plyse hervorrnft, so ergibt sich, dal das solche Lisungen sind, welche den 

sehen Druck (und gieichen Gefrierpunkt) haben. Solche Liisungen nennt man isotonises. 





Von tierischen Zellen sind auf ihr osmotisches Verhalten zuerst die 
Blutkérperchen von Hamburger®® untersucht worden, nach thm 
Koeppe™, Hedin®?, Gryns® u. a. Die roten Blutkérperchen verhalten 
den Lisungen gewisser Salze gegentiber so, als ob sie von einer 
bran umgeben wiiren, die fiir Wasser durchgiingig, fir das betreffende 
undurchgiingig ist. Fur solche Salzlésungen gibt es eine Konzentration, 
er die roten Hlutkirperchen weder schrumpfen noch quellen, sondern 
olumen unveriindert behalten; eine solehe Lisung ist zB. eine 0,9, 
-Lisung. Diese ist daher flir die roten Blutkirperchen des Menschen 
es Siiugetiere) als ,physiologische Kochsalzlisung* zu _bezeiehnen 
Froschblutkérperchen ist es eine 0,6°/, NaCl-Lésung). Eine 0.9%, 
-Lisung hat denselben osmotischen Druck (und denselben Gefrier- 
t) wie das Plasma des Blutes und wie der fliissige Inhalt der roten 
dirperchen; sie ist mit diesen Fltissigkeiten isotonisch. In Kochsalz- 
gen hoherer Konzentration (Hyperisotonie) geben die roten Blut- 
srchen Wasser ab und schrumpfen; in Kochsalzlisungen geringerer 


[$13] Osmotisches Verbalten der roten Blutkirperchen. 


Konzentration ay isotonie) quellen sie unter Wasseraufnahme 
Anderangen des Volumens der roten Blutkirperchen in Salzlésung 
sehiedener Konzentrationen kinnen mit dem Hisasoerien (relat 
nachgewiesen werden. Hat die Quellung einen issen erre 
platzt die Membran, das Hiimoglobin trennt sich vom Stroma 1 
sich in der umgebenden Flissigkeit: das Blut wird lackfarbig. 

Die roten Blutkérperchen sind aber keineswegs fir alle Su 
undurehliissig, sondern flr eine Reihe von Stoffen vollstindig dure, 
Permeabilitit der roten Blutkérperchen, Diese Substanzen mu mai 
scheiden in solche, welche fiir die roten Blutkérperechen aittig, und 
welche nicht giftig sind. Zu den letzteren gehirt z. B. der Har 
Fir diesen sind die roten Blutkirperchen vollig durchlissig; Harn: 
Blut hinzugesetzt, verteilt sich gleichmibig auf Blutkérperchen und 
Daraus ergibt sich, da der Harnstoff in seinen Lésungen tiberhaupt | 
osnie nisin Druck auf die roten Blutktrperchen austiben kann, « 
ja seinem Eindringen keinen Widerstand entgegensetzen. In He 
ljsungen jeder Konzentration verhalten sich daher die rote 
kérperchen wie in destilliertem Wasser: sie lassen das Hb austretei 
man dagegen Harnstoff etwa zu einer Kochsalzlésung, welche an + 
roten Blutkérperchen unveriindert 1a6t, so bleiben dieselben nach + 
unvertindert: der Harnstoff ist also an sich nicht giftig. Ganz ande 
hilt sich cine Gruppe von Stoffen, als deren Typus das Ammi 
chlorid gelten kann, Filr diese sind die roten Blutkérperchen dure 
zugleich aber wirken diese Stoffe auch direkt giftig auf die rote 
kbrperchen. Sie bewirken daher auch dann die Auflisung derselber 
man sie zB. zu einer Kochsalzlisung hinzufligt, die an sich fir di 
Blutkérperchen indifferent ist. 

Es besteht sehlieflich aber auch eine Permeabilitiit de 
Blutkirperchen flir gewisse Lonen. So sind die roten Blutktrperch: 
villig undurchliissig fiir die elektropositiven K- und Na-Ionen der 
salze, dagegen durchlissig ftir die elektronegativen Siiure- 
CO,, Cl, NO,, 80, u.a. Es kann aber ein Kindringen von Tonen 
roten Blatkirperchen nur stattfinden, wenn zu gleicher Zeit ein 
gleichwertiger Tonen aus den roten Blutkirperchen erfolgt. Brin; 
z. B. CO,-haltige rote Blutkirperchen in die Lisung eines Alka 
so treten CO,-Ionen aus den roten Blutkirperchen in die Salzlésun 
zugleich aber Siiure-lonen der Salzlisung (Cl, NO,, SO.) in dit 
Blutkérperchen hinein. Dabei wird die Salzlésung (durch Na, CO,) al 


Dic Pormeabilitit der Membran der roton Blutkixperchon fir gewisse Sto 
Undurchgingigkeit fiir andere Stoffe hiingt nach Oreréon®* von dem Gehalt der Mei 
Lipoiden (vgh pag. 21) ab; in der Txt sind in dem Stroma der roten Blutkirperch 
sterin und Lecithin in yerhiltniemaBig grofer Menge gefunden worden (§ 23), Diajenig 
wolcbo lipoid-lWalich sind, vyermogen die Membran xu durebdringen, fir die 
unlislichen ist sle undurchgingig, 


Der Gefrierpunkt des menschlichen Blutes liegt bei — 
er zeigt nur geringfigige Schwankungen [0,54—0,58° (Strauss 5)| 
den verschiedenartigsten Kinfliissen hat das Blut die Fihigkeit, sei 
lekulare Konzentration (deren Ausdruck ja der Gefrierpunkt is 
unveriindert zu erhalten, Transfundiert man einem Tiere Salzljsu 
das Geftiisystem, so werden die fremdartigen Substanzen sehr sch) 
dem Blute in die Gewebe deponiert, respektive durch die Nieren 
schieden; auferdem tritt Wasser aus den Geweben in das Blut: av 


Auflisang der roten Blutkirperchen, Hiimolyse_ 


» wird die veriinderte molekulare Konzentration sehr bald zur 
kgeftihrt. 


Pathologisches. So erklirt os sich auch, da unter pathologisehen 
‘ Veriinderungen des Blutgefriorpunktes meist nicht beobachtet werden; bel. =. 
on Nieronloiden mit Insuffizienz der Nierentiitigkeit und besonders bel uriimir 
Kranken wird eine Steigerung der Gefrierpunktserniedrigung fiber 0,6° 
borhaften Krankheiten ist dagogen dic Gefrierpanktserniedrigung geringer als normal 
nel", Cohn, Neudbrifer**). 





4, Auflisung der roten Blutkérperchen, Himolyse.” 


Die Auflésung der roten Blutkérperchen, die Trennung yon Hiimo- 
a nnd Stroma (Hiimolyse) kann durch cine grofe Zahl sehr ver- 
lenartiger Einwirkungen herbeigefiihrt werden; das Himoglobin lst 
Jabei in der umgebenden Fitissigkeit und das vorher deckfarbige 
wird lackfarbig. Gemeinsam scheint allen diesen Einwirkungen 20 
da6 sie, mechanisch oder chemisch, die roten Blutkirperchen schwer 
igen und ihre Lebensfihigkeit aufheben. * 
Nach Koeppe sind die roten Blutkérperchen von einer halbdureh- 
gen Wand umgeben; diese Wand besteht aus fettiihnlichen Stoffen 
iden, vgl. pag. 21) oder enthilt solehe: Zerstiirung oder schon Ver 
ng dieser halbdurchlissigen Wand macht das Blut lackfarbig. 
eser Weise wirken die folgenden Momente: 
1. Wiirme. Erwitrmen des Blutes tiber 65—68° hat Auflésung der 
Blutkirperchen zur Folge (vgl. pag. 40), indem die fettthnliche 
d schmilzt. 
2. Zusatz von destilliertem Wasser im Oberschub (vgl. pag. 33). Der 
itige Unterschied des osmotischen Druckes innerhalb und anBer- 
der roten Blutkirperchen bringt diese zum Aufquellen and bewirkt 
Blich Platzen der halbdurchliissigen Wand. 
Wird Bint mit viel destilliertem Wasser versetst, so sind die Stromata unter dem 
kop ohne weiteres nicht sichtbar, sie kinnen aber durch Zusatz von Mothytviolett 
und sichtbar gemacht werden (Koeppe). 
Wioderholtes Gefrieren und Auftanen des Blates wirkt ebenfalls h&molytieds. 
jofrieren friert roines Wasser aus; beim Anftanen der ontstandenen Kis 
\lso, wenn auch our fir kurze Zeit, reines Wasser auf die Blotkirperchen und 
sie infolge der Differenz des osmotischen Druckes zum Platzen. 
Kine rein mechanischs Zorstirang der Wand der roten Blutkiitperchen kann aneb 
Vorroiben mit Seesand erreicht warden; bei nachtriglicher Behandlang des Breies 
ttonixchon Flissigkeiten findet Lisang des Himoglobins statt (Rywosch®), 
8. Fettlésende Stoffe (Ather, Chloroform, Aceton, Alkohol usw.) 
n hiimolytisch, indem sie die fetthaltige Wand der roten Blutk& 
auflésen. Auger einer bestimmten Konzentration des iitmolytiechen 
3 ist fir die Wirkung eine bestimmte Temperatur notwendig, 
dieser ist das himolytische Agens an sich unwirksam (Koeppe®), 
kehrt kinnen aber auch Stoffe, welche selbst in den Lipoiden der 
ran der roten Blutkirperchen lislich sind, infolge dieser Eigen- 
in die Membran eindringen, sie schiidigen und so Hiimolyse herbei- 
1. Auf diese Weise bewirken Seifen, Fettsiiuren, die ungesiittigten, 
Msiiure (Faust u. Tallqvist), aber auch die gesiittigten, z. B. Palmitin- 
(Shimazono®), ferner Lipoide, wie das Lecithin, Hiimolyse. Diese 
kUnnen auch durch ihre Einwirkung auf die Wand der roten Blnt- 
rehen die Wirkung anderer Substanzen. die an sich nicht oder wenig 








[s14) Aaflisung dor roten Blatktirperchen, Himolyse. 


himolytisch wirksam sind, fdrdern, diese Stoffe ,aktivieren“ 
Wirkung des Lecithins auf Kobragift, pag. 47). 


In diese pe gehirt anch die himolytische Wi der Galle nt 
sauron Salze sowie der sogenannten Saponingubstanzen (Kobert™), — 
pr Substanzen dieser Grappe wird durch Cholosterin gehemmt 

m*), 

4. Stturen und Basen wirken lisend auf rote Bingeorpent 
Wirksame dabei sind die H- resp. OH-Ionen (vgl. . BA). 
tritt der Wirkung ist notwendig eine gentigende Konzentra 
H- resp. OH-Ionen, eine bestimmte Temperatur und sehlieb 
gewisse Zeit der Einwirkung. Nach K “ handelt es sich 
Wirkung der H-lonen um eine katalytische Spaltung, bei der 
der OH-Ionen um eine Verseifung der fettihnlichen Substan 
Wand der roten Blutkérperchen, 

5. Durch olektrische Einwirkungen werden rote Blutkirperchon 
Konstante Strimo, Induktionsstréme, Wechsolstrome wirken vorwiegend durch Er] 
clektrolytische Zersotxung (Kollett', Hermann ®, Cremer™, Drschewetzky™). ¥ 
von Leydener Flaschen, Kondensatoren wirken dagegen durch cine nicht nithe 
cloktrische Kinwirkung auf die roten Blutkirperchen (diese kann durch Zusate 
losungen verhindert werden, nicht jedoch durch Zusatz von Zuckerlisungen) (Ae 

Kine grofbe Gruppe himolytisch wirkender Substanzen (Hin 
im engeren Sinne) nimmt nlilber den bisher erwiihnten eine 
stellung ein: sie dihneln in ihrem Verhalten durchaus den giftig 
wechselprodukten gewisser Bakterien, den sogenannten Toxinen 
ebenfalls SuBerst labile Substanzen; sie veranlassen, in den T 
eingefithrt, die Bildung von Schutzstoffen, sogenannten Antik 
Antihimolysinen, ebenso wie die Toxine die Bildung von Ar 
auslésen, die ihre Wirkung aufheben; und ihre Wirkung ist str 
zifisch (s. pag. 46). 

Die Bildang und Wirkung der Antitoxine orklirt sich nach der yon Eh 
gestellten Soitenkettoatheorie, die auch fir das Verstindnis der Wirkung 
lysine und Antihimolysine yon grunifegender Bedeutung geworden ist, in folger 
Nach Fhrlich hat man an dom lebenden Protoplasma zu unterscheiden den I, 
korn, der das eigentliche vitale Zentrum darstelit, und zablreicho, an diese 
Seitenkotton oder Receptoren, die den cinzelnen Funktionen der Zelle, » 
allem auch der Ernihrang derselben, dienen. Die Seitenketton oder Recoptoren 
komplexe im Molekil des Protoplismas, die infolge ihrer chomischen Konfiguratic 
sind, andere Substanzen, 2B. Nabrungastotte, aber anch Toxine chemisch xn 
verankern; sie yerbinden sich dabei mit bestimmten Aosigrepped der 20 binder 
die als ,haptophore Grappen* bexeichnot werden, Die Bindang xwischan der t 
Gruppe cinos Nahrongastoffes oder eines ‘Toxins nnd den daza passenden Rece 
Zolle ist die Vorbodingung fir die gegenseitige Kinwirkung, Findet also oin Tox} 
Organismus elngefihrt, dort keine fiir dasselbe passenden Receptoren, so verm 
nicht giftig auf denselben zu wirken, dor Organiemns ist .immun* fiir das 
Toxin (natirlicho Immenitht). Am Toxin hat man von der haptophoren Gray 
nar die Bindung un den Receptor der Zello vermittelt, streng 2u unterscheider 
Grape, welche nach erfolgter Bindung die eigentliche Giftwirkung ansibt; « 
toxophore Grappe bezeichnet. 

Wird ¢in Toxin in einen fiir dasselbe empfindlichen Organismus in einer 
gofiihrt, die nicht den Tod bedingt, so wird es also an die passenden Receptoren 
gebanden. Dadnreh warden diese aber fiir thre Anfiraben, %. B. Nabrungestotte 
auBer Funktion gesetst, Der Leistungekern bildet nun xam Rraats deraelben neue 1 
diese Neubildung geht aber fber den etwa gerade notwendigun Ersatz hinans an 
seiner Cherproduktion vou Receptoron, die schiieBtich am Protoplasma nicht mehr } 
und in die Btutbahn abgestofen werdon. Diose froi in der Blutbahn befindlichen 
sind die Antitoxino; sie vermigen die Toxine vermittelst ihrer haptophoren Grupp’ 
und dadnrch yom Protoplasma abxubalton (kfinstliche Immunitat). Ders 
also, der, solange er als Receptor am Protoplasma sitzt, die Vorbedingung der 
ist, stellt, wenn er sich frei in der Blutilfissigkeit befindet, die Ursache der at 
Wirknng dar. 











Himolysine des Blutserums. Ambocoptor und Komplement, 





Nach der Khrlichachon Theorlo kommt auch die Wirkung der Himolysine 
tde, wie die der Toxine; die roten Blutkiirperchen beeitzen Receptoren, 
am haptophoren Gruppo der Himolysine verbinden und so deren Wirkung “anf 
qehen vermitteln. 
Himolysine des Blutserums. Das normale Blutseram vieler 
e igenschaft, die Blutkjrperchen einer anderen Art d 
Hundeserum und Froschseram die Blutkérperchen des Ke 
§ P (Landois"), Diese himolytische Fuhigkeit des Blutserums, die 
nur in verhiiltnismibig geringem Mafe vorhanden ist, kann | 
stlich stark gesteigert oder bei einem Tier, dessen Serum an 
hiimolytisch wirkt, hervorgerufen werden durch Immunisie 
8s Tieres mit den Erythrocyten einer anderen Art f 
lert man einem Tiere AG B. einem Meerschweinchen) defibriniertes 
anderen Tierart (z. B. Kaninchenblut) mehrmals intraperitoneal 
ttan oder intravents), so bekommt das Blutseram des so yorbe 
a Tieres die Fuhigkeit, die Blutkirperchen der Tierart, die ; 
ktion benutzt waren, aufzulisen: spezifisehe Wirkun Ss 
itt, aber nicht die einer anderen Tierart (das Blutseram pi 
delten Meerschweinchens list nachher Kaninchenblutkérperchen, 
liese, nicht die einer anderen Art). . 
Sehr stark hiimolytisch auf Kaninchenblutkirperchen wirkt das Aalseram (Comet 


y — 

Der tlorische Organiamus hat ganz allgemein dio Fahigkslt, gegen fremdartizes 
al, das in ihn cingefabrt wird, spexifische Antikorper xu bilden. So kimnen auc 

Finfihrung anderer Zellen (Flimmerepithelion, Spermatozoen, Leukooyten, 

usw.) Substanzon produziert werden, welche diese Zollen Wien: Cytoly aime, 
trnng von Baktorlon ontatchen go dio Bakteriolysine. 

Zur Erzengung von Ulimolysinen gentigt die Tnjoktion anBerordentlich geri: 

n dos fremdartigen Blutes. Sache’ erzengt» beim Kaninchen Himolysine noch 
pniise Injektion von nur 0,125 cm* Ochsenblut, Kriedberger u. Dorner sogax a 
ion einer Erythrocytenmenge von 1—1,5 mg cincr 5%/,igen Blutanfxchwemmung. 

Die Himolysine des Blutserams (sowohl ‘in normalen Seram vor- 
enen, wie die durch Immanisierung erzeugten) bestehen nun 

Substanzen: die eine Substanz ist verhilltnismibig widerst 
o iiuBere Einfltisse, vertriigt vor allem eine Erwiirmung auf ca. 
ist thermostabil), sie wird als Amboceptor bezeichnet; die 
tanz ist leicht zerstérbar, so besonders durch Erwiirmung ‘auf 55° (ele 
aermolabil), sie wird als Komplement bezeichnet. Bei der Tm- 
isierung entsteht neu nur der Amboceptor. Das Komplement 
agegen schon im Serum auch des nicht immunisierten Tieres vor- 
en; es kann aber auf die roten Blutkérperchen nicht eher wir 
is es durch Vermittlung des Amboceptors an dieselben gebunden wird. 

Belspiel: Das normale Sornm dos Moorschweinchons lst nicht die Blntkiirperehea 
ininehens; es enthilt nur Komplement, keinen Amboceptor. Wird cin Meerschweinehen 
Injektion mit Kaninchenblut vorbchandelt, <0 enthilt das Immunseram ninmebr anfer 
Complement auch den durch die Immunisierung entstandenen Amboceptor; es wirkt 
himolytisch. Wird dieses Immunserum '), Stunde auf 55° erhitet, so verliert os seine 
ytische Wirkang, es wird inaktiviert, weil das Komplement xeratirt wordem ist; 
hilt nur noch Amboceptor, Ks kann aber durch Znsate normalen Meerschweinchen- 
4 reaktiviert werden, Normales Meerschweinchenseram enthilt Komplement, aber 

Amboceptor; inuktiviertes Immanserum enthilt Amboceptor, aber kein Komplemant: 
fiir sich ist daher unwirksnm, gemischt wirken sie dagegon hiimolytisch, weil im der 
ing die beiden wirksamen Substanzen vorhanden sind. 

Der Unterschied im Vorhalten yon Amboceptor und Komploment gegentiber der Wilrme 
ordings nicht durebgiingig vorhanden: es gibt auch sowoh) thermolabile Amboceptoren. 
ch thermostabile Komplemento, 

Nach der Ehrliehschen Theorie besitzt der Amboceptor xwei haptophore 

der Name Amboceptor); mittelst der einen haptophoren Grappe vereinigt er 































\aXy A niihiimolysine, Agglutinine, Himolysine tier, Gifts, Bakteriohimolysine. 


{swe exuteprechenden haptophoren dos Blutkixperchens, diese Gruppe 
pote desrragen a Aorta doce Dezeichnet. Mittelst der anderen 


sogenannte zy motoxixehe (# ‘end der toxophoren dor ". 

Dareh Vorbebandiang mit Blutkorperchen dorselben Art konnon auch | 
erxengt werden, welche die Blutkorperchen von anderen Angehorigen derselbe 
xulisen imstande sind, sogenanate Isolysine. Niemals dagegen golingt os, Him 
gewinnen, welche die eigenen Blutkirperchen des Ticros auflisen (Autoly sine 
Maragliano™ soll bei zahireichen Krankheiten das Serum die eigenen Et 
zagrnnde richten. 

Darch Immunisierang mit hiimolytisehem Serum kann me 
hiimolysine erzengen, welche die Wirkung der Hiimolysine auf 

Da das Hiimolysin ans Amboceptor and Komploment besteht, die drei 
Grappen besitzen, zwei am Amboceptor und eine am Komplement, so sind je ns 
der Wirkung drei rerschiedene Antikirper denkbar: zwei, wolebe die eine oder 
baptophore Groppe des Amboceptors binden: Antinmboceptoren, und anf 
Antikrpor, weleher die haptophore Gruppe des Komplomonts bindet: Antikom 

Den Himolysinen nahe stehen dio Agglutinine, welche Agglutination 
Blutkirperehen bowirken (8 gibt auch Agelutinine, welche im gleichen Sinne aui 
wirken). Man yersteht unter Agglutination eine Vorklumpung der Zellen unterei 
Hanfen, die mikroskopiseh etkannt werden kann, aber aneh das makroskopische 
verindert: groBere Senkangsgeschwindigkwit der zusammengeballten Blutkorpercher 
gingigkeit darch Papierfilter, Solche Agglutinine sind gowisse giftige Substanzen y 
Ursprungs, Phytalhumosen (Kobert™): Ricin aus den Samen von Ricinns 
Abrin ans den Samen von Abrus procatorius ua. Auch im normalen Serum sind 4 
vorhanden oder kinnen durch Immunisierung in dem Serum erzeugt werden. Dio J 
des Serums ertragen ein Erhitzen anf 60°, sie finden sich dahor noch im in 
himolytischen Sernm. 

Himolytisch wirken auch gewisse tierische Gifte, so 2, B. 
von Bienen, Spinnen, Kréten und Sehlangen. Vom Schlangengii 
wiesen, da® es ebenso wie die Hiimolysine des Blutserams die A 
der Blutkérperchen durch cin Zusammenwirken zweier Sub: 
herbeifithrt: das Schlangengift selbst ist dabei der Amboceptor, i 
des Komplements wirkt das Lecithin (Kyes7*). Der Amboce) 
Schlangengiftes, z. B. des Kobragiftes, vereinigt sich dabei mit dem 
zu einer neuen Verbindung, dem Kobralecithid, welches sich dur 
Lislichkeitsverhiiltnisse sowohl von dem urspriinglichen Kobragift, 
von dem Lecithin unterscheidet; das Kobralecithid kann rein di 
werden. — Die Himolyse durch Kobragift und Lecithin wird dure 
stearin stark gehemmt, 

Die Stoftwechsolprodukte zablreicher Bakterien wirken hiimolytisch , 
‘Totnnusbacitien, Cholerayibrionen, Typhusbacillen, Colibacillon, Staphylocakken 
normalen Serum mancher Yiero sind Antikirper dieser Himolysine yorhand 
Immunisicrung yon Tieren mit Hiimolysinen kinnen sie kiinstlich ersougt wert 
entapricht einem bestimmten Hamolyxin auch stets cin bestimmter Antikerper, d 
Wirknng des entsprechenden Himolysins anthebt, nicht aber die anderer Hiimo 
schiitzt 2% B, das durch kinstliche Immanisierang yon Kaninchen mit Staphyloly 
lyain der Staphylocokken) erhaliene Antistapbylolysin Kaninchenblatkiirperchen 
die Wirkung des Stapbylolysins, aber nicht gogen die des Tetanolysins (Him 
‘Tetanusbaciilen). 

Die roten Blutkirperchen besitzen gegentiber hiimolytise’ 
menten einen bestimmten Grad von Widerstandsfihigkeit (Res 
Diese Widerstandsfithigkeit ist verschieden bei verschiedenen Tiere 
aber auch ab von der Art des angewendeten hiimolytischen Age 
Blutart ist x. B. um so weniger resistent gegen Saponin, je resist 
gegen Wasser ist (Ryroseh*). Die Blutkirperchen desselben Indi 


‘Lisung auflisen, und d 
mten, welche schon yon einer 0,6%,igen NaCl- 
n, gibt es alle ichen Ubergangsstufen (. 
iingere Blutkérpere! resistenter als iiltere (, 
embryonale Blutkirperchen den meisten hiim 
tiber resistenter als die des erwachsenen Tieres (Rywosch?), 


Bei Ikterus, Infektion, Magencarcinom Ist die Resistenz dor 
hen gegen hypisotonische NaIdisungen erhoiht (Lang™), die Resi: 

t bleibt dabel jedoch unverindort (Port), Bel pernizivsor Animie 

Ideton roten Blatkdrperchen cine besonders geringe Widerstandsfihigkeit 

ich wirkenden Schiidlichkeiten 2u besitzen. ¥ 
Das Himoglobin vermag seine Aufguben im Korper nur so lange 0 erfillem, 
roton Blutkirperehen gebunden ist. Kommt es zu einer Auflosung yon rotem 
hen und Ubertritt von Hiimoglobin ins Plasma (Himoglobinimie), 80 

obin ausgeschieden: zuniichst nimmt die Leber das Himoglobin anf and 
tallenfarbstoffe; gentigt das nicht, um das freie Himoglobin aus dem 

‘nm, #0 scheiden os die Nieren aus: Hiimoglobinurie, Bei dor paroxys: 
globinuria kommt es ans noch nicht nithor bekannten Ursachon 

ing von roten Blutkirporchen und Hb-Ansscheidang im Harn, 


15. Form, Gréfe und Zahl der Erythrocyten. 
yerschiedener Tiere, 
Die Siiugetiere — haben kreisrunde Blutkérp: 

ensch, nur von verschiedener Gréfe. Eine Ausnahme machen 

; Alpaka und deren Verwandte; diese haben lancicieal ae 
rchen ohne Kern, Die Vigel, Reptilien, Amphibien und Fi: 
liinglich-elliptische Blatkérperchen mit Kern; eine Ausnahme 
‘ischen machen die Cyclostomen, welche kreisrunde Blutkérpe 





Grd He (x=0,001 mm) 
der olliptischen Blatkorperchen 
Kleiner Durchmesser | 





dor kroisrunden 
Biutkirperchen 





























Lama 4,2 
Taube 65. 147 - 
Frosch 16,3 - 23,0. 
‘Triton 19,5, 29,3. 
Protens 36,6. 58,2. 





Die Korperchen des Lurchos Amphiuma sind noch 
wegen ¢in Drittel grifer als die des Proteus, 





| 
| 
Moschuatier 2,9 | 
Unter den Vortebraten — hat Amphioxus farbloses Blot, Die griBeren Blutkixper 
Amphibien sind mit blofem Ange sichtbar. Jo griBer die Blutzellen sind, am #0 
r muB die Zahl und die gesamte Oboriliiche dersolben in cinem Volumea Blut sein. 
{ den Vigeltn ist trotz der bedoutendoron GriiBo der Kirper ihre Zahl doch relatiy 
alg in don anderon Klassen dor Vertobraten. In 1 mm? hat das Lama 18186 000, 
ze 9900 000, das Pford 7400000, Aff, Kaninchen, Hund tiber 6000000, der Breb- 
400.000, die Kidechse 1292000, der Frosch 408900, Protens 38 600 Bh 

nterschlafe sah Vierord? beim Mormeltiers die Zahl von 7 Millionen auf 2 Milliopes 
n® abnehmen, — 
Die Wirbellosen™ — besitzen entweder farbloges Blut mit farblosen Zellen oder 
ss (rotes, violottos, briianliches, grines, blanes) Blut; in lotzterem Falle kanm der 


j 


| 


{ 
I 






[ $16] Entstehung der roten Blutkiirperchen, 


vor 
und den niederen Crustaceen. Andere rosplratorische Farbstotfe sind: das Rehi: 
(rot) der Eehinodermen, das Chioroeruorin (grin) and Hamerythrin 
Wirmer, das Hamocyanin (blau) der maltese und Orustaceen, Das 4 
ist cin knpferhaltiger, O-bindender Farbstoff, es ist von Menze** 
worden, Er vermag nur '/, so viel Sauerstoff wie Hiim a binden; ay 
O-baltige Blut ist blan, das vendse farblos (vgl. Kobert™, Winterstein™). In 
kOrperchen des Blutes der Ascidien fund Henze™ cin Chromogen, das Vanad 
halt; dieses Chromogen nimmt jedoch keinen Sauarstof? a auf. Die Blutkirperchen de 
enthielten auBerdem 3%), freie Schwefelvinre. —Im Blute einiger Mollusken nnd 
sollen auch respiratorisehe, sauerstofbindende Kirper ohne besondere Fiirbung vo 
soxenannte Achroglobine. 


16. Entstehung und Untergang der roten Blutkirper 


Entstehung der roten Blutkérperchen. 

Embryonale Entwicklung. Im Embryo entstchen die ersten rot 
korperchen in den sogenannten Blutinseln dex Geffihofes. Die znerst 
Striinge angelegten Blutgefiie erhalten durch Bindringen von Flissigkeit cinon 
im Innern, in welehen yon der Wand her Hanfen locker miteinander verbundener 
Zollen hineinragen. Diese Zellen, die xundchst noch einen Kern enthalten und , 
de fertigon Erythrocyten sind, wandeln sich in rote Blutkirperehen um, indem 
stoft in ihnen anftritt, sen sich von den Zellhanfon ab und gelangen #0 in diet 
im Innorn dor GefiBo; sie vermehren sich weiterhin durch Teilung. 

Im weiteren Verlaufe der embryonalen Entwicklang wird die Bildung 
Blutkirperchen in bestimmton Organen tokalisiert; als solche kommon in Be 
Leber, spiiter die Milz, dio Lymphdrisen, endlich das rote Knochenmar 
letzten xwei Dritteln der Embryonalentwickiung (beim Rind und Schaf) ist 4 
Knochenmark (noben der weniger wichtigen Milz) das hanptsichlichste Dutbilat 
Nach Kintritt des Knochenmarks in die Reihe der Blnthildungsorgane geht die | 
der Leber fiir die Blntbildung xnriick (Jost), 

Ans den stets xuorst kernhaltigon Blutkirperchon des Kimbryo (Bry thre 
ontstehen erst im spiiteron Verlanfe des Embryonallebens die charaktoristisch gosta 
sugleich kerntosen. Beim menschtichen Embryo sind in der 4, Woche nur kernbaltiy 
chon vorhanden; im 3, Monat betragt ihre Zahl our noch gegen y—"g aller Ey 
1m Ende dos Potallebens trifft man normalerwoise im stromenden Btute keine ke 
Blutkorperchen mehr an; sio finden sich nun nur noch in den blathildenden Org 

Im extranterinen Leben werden die roten Blutkérperchen 
sonderen blutbildenden Organen gebildet, und zwar ist bei 
schwiinzten Amphibien und Fischen die Milz, bei allen tbrigen Ver 
das rote Knochenmark der Bildungsherd (Bizzozero™ 1866, New 
Hier entstehen die roten Blutkérperchen aus kernhaltigen Ged 

»Erythroblasten*; der Kern wird bei der Batik nach 
Autoren (Kolliker %*, Neumann, Knoll) im hiimoglobit altige 
plasma aufgelést. nach anderen (Rindfleisch™) tritt der Kern 
Zelle aus. — Die Erythroblasten selbst entstehen wahrscheinlich 
facher Weise: einerseits durch Zellteilung aus schon hitmoglobin 
Zellen, andrerseits aus farblosen Mutterzellen, welche sich in 4 
haltige umwandeln, 

Bei der Geburt enthalten alle Knochen rotes Mark, im Vorlaufo des Wachs 
dieses jedoch allmiblich durch gelbes Fettmark ersotzt, so da beim Erwachsener 
in den platten und kurzen Knochen des Schidels und des Rampfes rotes (blu! 
Mark findet, die langen Robrenknochen der Extremititen enthalten entweder nur 
oder es enthalten nar die oberen Teile dex Femur und Humerus rotes Mark. B 
siveren Regencrationsprozessen des Blutes kann sich das Fettmar! 
in rotos verwandeln, und zwar yon jenen oberen Hnden an abwiirts solbst 
Knochen dor Extremititen hindureh. Sogar in den verknicherten Kebll 
pathologisehen Knochongeschwélsten kann rotes, Blutkirperchen bildendes 

Landols-Rosemann, Physiologic. 1*, Aat 

















Untergnng der roten Bintkérperchen. Dis wekfen Blatkorperchom 


« Bei ‘Tioren kann man die Erscheinung durch kitnstliche Blntverluste es 
an (Littes u. Orth”), Winterschilifer haben wihrend des~ Wintersehlafi 
o Fettmark; beim Erwachen wandelt sich dasselbe ebenfalls von den 0 

\ abwiirts in rotes Mark um (Pappenheim’). Binen ihnlichen periodischen V 
a Spatt 


fthsommer) beobach! beim 

Unter pathologischen Verhaltnissen kinnen auch Milz und Leber » 

der Biutneabildung za beteiligen. . 

Untergang der roten Blutkirperchen. Da die fertigen rot 

inperchen keinen Kern mehr haben, so konnen sie sich auch 1 

vermehren; sie gehen nach einiger Zeit zugrande und werden 

4, in den blutbildenden Organen nen gebildete ersetzt. Wie lang 

sdauer der roten Blutkérperchen ist, 1i6t sich nicht an; en 1 

Annahme, da6 sie nur etwa vier Wochen betrigt, diirfte sicherlich zu 

g sein, sic betriigt mindestens 70—90 Tage oder mehr (Rubner %*). = 

imelzung erfolgt vor allem in der Milz and den lymphoiden Biel fool 

aden wich Zellen, welche Blutkérperchen oder ae in sich 

. Auch in der Leber findet eine Einschmelzung roter Bh 

la die Gallenfarbstoffe sich vom Blutfarbstoff ableiten ( 

Der Blutfarbstoff der eingeschmolzenen roten Blutktrp: eee 

ler rot gefiirbte eisenfreie Furbstofle: Hiimatoidin, Bilirabin, 

Ibraun bis schwarz geftirbte cisenhaltige Pigmente: Hitmosiderin, 

iin. Ob die Reste des Hiimoglobins eventuell wieder zur Neubil 

Blutkirperchen verwendet werden kinnen, ist zweifelhaft; ein 

isens wird jedenfalls durch die Leber ausgeschieden. 

Casehenberser fand im stréimenden Blute farhige und farblose pr welche 
die Einschm ee ee ieeseioceoes Lise) eee mo 

eyten hervor end zeigen teils die Bisenreaktion des Himatosiderins, teils die des 

bstoffes. In der Milz nnd im Knochenmark werden diese Schollen dann zurfickbe 

md weiter verwandelt. 

Nach Asher! ist die Milx cin Organ dos Eisenstoffweehsels, das dazm diest, 

wochsel frei werdendes Risen vor Ausscheidung zn bewshren und s9 fiir die Zwecke 

tanismus zu erhalten. Nach Exstirpation der Milx war bei Hund (Grossenbacher™', 

‘mann'*) snd Mensch (Bayer) dic Eisenausscheidung gesteigert. 

Pathologisches. — Manche Andmion (vgl § 18) sind anf eine vermehrte Zer 

& der roten Bintkirperchen xurdckzefihren. Es findet sich dann cine 

vahaltigem Ma! 1 aus cingnechmolzenes rotes Blutkorperches in der Leber, sowie 

nnd Knochenmark. Stockt die Aussebeldang des Fisens in der Leber, #0 haat 

sunichst hier an; weiterhin ist es auch im Blutplasma reichlicher vorhanden amd 

teh durch andere Driisen ubgeschieden, resp. in den Zellen derselben (Nierenrinds, 

8) abgelagert werden (Quincke'), 


. Die weiSen Blutkérperchen (Leukocyten) und die 
Blutplittchen, 


(I. Die weifen' Blutkirperchen oder Leukocyten’®* kommen auber 
tte (Hewson, 1770) auch in der Lymphe, dem adenoiden Gewebe, 
tnochenmarke und als Wanderzellen an vielen Stellen der Binde- 
aren, aber auch zwischen Driisen- und Epithelzellen vor. Sie bestehen 
igeligen Kliimpchen eines klebrigen , homogenen oder granulierten, 
amare weichen, bewegungsfihigen, ‘hilllenlosen Protoplasmas 

Frisch (A) zeigen sie keine Kerne; diese erscheinen erst nach 
be: oder Essigsiiure-Zusatz (B), wodurch zugleich die Umgrenzung 
tr hervortritt. Wasser macht dazu den Inhalt kérniger, tritber, Essig- 
hellt ihn stark auf. Innerhalb der Kerne zeigen sich cin oder mehrere 
Urperchen, Der Durchmesser der Zellen weehselt von 4 bis 13 jy. 








[17.1 Dio weifen Blutkirperchen. 


Die Leukocyten kinnen nach ihrer Form, nach der Artihres Pro 
mas, welches bei den einen homogen ist, bei den anderen Kia 
(Granula, Granulationen) enthilt, und nach dem Verhalten 
Kérnchen gegen Farbstotfe in verschiedene Arten (Fig. 8) cingeteilt | 
Fin Teil der Kérnchen firbt sich nur mit sauren Farbstofien: oxyphil 
eosinophile, ein anderer Teil nur mit basischen: basophil 
letzter Teil nur mit neutralen; neutrophile Granulation, Danact 
scheidet Lhrlich*** im normalen Blute: 

1. Die Lymphocyten: kleine, an Grélic den Erythrocyten & 
Zellen, mit groBem, rundem, sich mit allen hasischen Farbstofien fir! 
Kern und diinner homogener Protoplasmarinde ohne Granulati 
normalen Blute etwa 22—25°/, der farblosen Zellen. (Fig. 8, a, 6, 

2. Die grofen mononucleiiren Leukocyten: zwei- bis : 
so grof wie die Erythrocyten, mit grofem, ovalem, meist exw 
gelagertem, schwacl 
barem Kern und + 


(F homogener protopl 
A © @ & @ scher Rindensehicht 
© rs Granulation. (Fig. 


Pig. %. 


B is ‘ 

3. Die Uber; 
formen: den vorigen 
abermitzwerehsacka) 

Loukocyten des Mutes oder weile Binshorperchen a Lae} gebuchtetem Kern; i 


ohne Yurate; — # diosel y 
Um hes i it grobh i 
Rrensung und hervort Se Oe toplasma tritt eine | 


Ker und wenig Pi = 
Te AD Ka ana gleich sichthar, neutrophileGranu 


Fig. & auf. Grappe 2 und 3 
zusammen etwa = 2 


stimtlicher Leukoeyti 
(Fig. 8, d,) 
4. Diepolynuel 


neutrophilen Let 
r g ten: etwas kleine 


% 
y- Groppe 2 und 3 mi 
g morphem, gelappter 
: vielgestaltig gewm 
oder in 3—4 durel 
h a & Chromatinfiiden mitei 


verbundene eile 
ander weichendem 
der sich mit basisehe: 


stoffen intensiy fitrh 

Area, dr Lentacren  t ieomorwe: —cemaermece: Protoplasma _ besitat 

nueloare neutrophile Leukeayten} — ; ¢ ensinophile Leuko~ dichte, sehr feine n 

SOR = LAS ees phile Granulatio 

normalen Blute etwa 70 bis 72°/, aller Leukocyten. (Fig. 8 e, fy, 

5. Die cosinophilen Zellen gleichen den vorigen, enthalte 

eine grobe, kugelige, in den sauren Farbstoffen intensiv firbbare G 

lation. Etwa 2—4°/, der farblosen Zellen. (Fig. 8, fi, é 

6, Die Mastzellen enthalten eine intensiy basophile Granu| 

yon sehr unregelmiibiger Gré®e und nngleichmibiger Verteilung. 1) 
malen Blute hichstens 0°5%/, der farblosen Zellen. (Fig. 8, &.) 









4 


Die weien Blatkirperchon, 








f puthologischen Biuto troten diese Formon nicht nur in verinderter Zahl auf, 
e# erscheinen auch noch andere Formen, die normalerweise im Blute rhe 


i awisehen den angranulierten Lymphoocyten (1) und den grannlierten Feed 
1 mit BinsebloS von 2 und 3; 5 und 6), diese beiden Zollformen stehen anch 
in keiner Boziehang 20 einander, Nach einer anderen Anschanung (ygh a i - 
entwickeln sich dagegen die granalierten Zellen aus den nicht 
io nontrophilen Lenkoryten (nicht die Lymphoeyten) des Menschen und der hiheren 
geringorom MaBe auch des Hundes (nicht der anderen Nore) enthalten ela Je ae 
os Ferment; Blotplasma und a ele haben einen hemmenden Finflo8 anf day 
Das Bint bei myelogener Lenkiimie zeigt (bei 50°) sturke Fermentwirkung 
aehrong der Leukocyten), das Blut bei lymphatischer Lenkliimie (Vermehrang: 
yen) keine (Miler u. Jochmann*). Auch ein diastatisches Ferment ist 
fake ton nachgewiesen worden (Haberlandt', Mancini), jodoch keine Lipase — 
12), Die Lymphocyten enthalten dagegen ein fettspaltendes Ferment 





Leukoeyten yermehren sich durch Teilung. Sie entstehen — 
| Lymphdriisen und dem adenoiden Gewebe iberhaupt, der 
nd dem Knochenmark, und zwar nach Ehrlich die Lyn 

in baw lymphatischen Apparat, die granulierten Leakey im 
mmark, 


fie Leukoeyten zeigen (besonders bei der Beobachtung auf dem 
mn Objekttiseh) eee (von Wharton Jones 1846 beim 
; Yon Davaine 

beim Menschen Fig. 9. 

atet), welche a 


veil sie den Be- 
jen der Amiben Ce ¢ @. 
men —_entspre- ; 
amiboide* ge- ” @ wa 
vat. Das Proto- ay 
ist dabei in 
abwechselnden 
ttion und Rela- 
um den Kern 


n; von der Ober- So é 
ited eens —— 

indet und wie- 

gezogen (Fig. 9) R 


t den Pseudo- — !rkecyten vom Menschen in amoboider Newogang begriffen. 


der Amiben). 
lo Beweglichkeit kommt nicht aur, wie man friher angenommen hat, den poly- 
Loukocyten, gondorn allen woien Blutkirperchen, auch den Lymphocyten xn 
e?, Deotien™), 
le Erscheinung kann bei 40° stundenlang beobachtet werden, in der fonchten Kammer 
‘ochen lang Bowegungen geschen worden. Jolly '* will in dem Blate von Batrachiern, 
tisch im Bisschranke aufbewahrt wurde, sogar nach 10 Monaten (!) noch ambbeide 
gen der Lenkogyton beobachtet haben, Bei 47° tritt .Wirmestarre* and ‘fod ein; 
igste Tomperatur fir die Moglichkeit der ambboiden Bowegung Wegt bel -- 14%. 
Bewogung notwendig. Unter dem Rintiub von Induktionsschlagen werden die 
en plitzlich durch inzichnng aller Fortsitze rund (wie gereizte Amoben), War der 
ws Schlag nicht 2u stark, so beginnen sie nach einigor Zoit winder ihre Bewogungen, 
nd anhaltende Schliige titen sie, lassen slo forner anfquellon und villig xergehen, 
verniehtet die Boweglichkeit der Leukocyten. 


fie Bewegung der Leukoeyten hat zweierlei Erscheinungen 2ur Folge: 
Die Wanderungen der Zellen, indem sie sich vermittelst pee 





1817) ZANE der weillen Blutkirperchen, 


Ausstreckens und Einziehens der klebrigen Fortsitze fortziehen ; 
Weise vermigen sie sogar durch die Wand intakter Gefiti) 
zuwandern* (vgl. § 65). — 2. Die Aufnahme kleiner Korneh 
Pigmente, Fremdki en) die zuerst der Oberfliche a 
ins Innere . eventuell spiiter wieder ausgestofen le 
(ealepieciceieter Walon Panicle der Amiben). 


Die Bewegungen der Leukocyten kinnen sognr nach einer bestimmton 
hin erfolgen, indem die Leukoesten (wie manche niedore Organismen) von gewi 
angelockt, von anderen abgestoBen werden: Ohemotaxis oder Chemotropismut 
Namentlich iben die Stoffwechselprodukte pathogener und nichtpathogen 
orgunismen eine starke anzichende Wirkang anf die Le ‘aus. Wenn 
x.B, Kolonien von Staphylococcus (Biterbakterien) an einer Stelle des er 
so locken deren Stoftweehselprodukte die Lenkocyten au den benachbarten Gefi 
entsteht entziindliche Reaktion und Eiterang. 

Dio Fithigkeit der Loakoey' kleine Kirnchen in sich anfsanehmen, 
deatung bel Rickbildungaprozessen, Indem die einzuschmelzenden Toile j 
von ihnen aufgenommen, also gowissermafen .gofrossen werden. Metschnik, 
die so thtigen Zellen daher FreBxellon* (Phagocyten). So wirken sic 
schmelzen des Knorpels und Knochens als Chondro- und Osteoklasten. 4 
verhaltende Zellen findet man im Schwanze der Batrachier, welche beim Sehwund 
wihrend der Metamorphose Teilchen der Gewebe, x. B. Fibrillentriimmer, in sich 
(vg auch Resorption dea Milehgebisses, § 103). Ebenso fand man auch in das Blat it 
Mikroorganismen yon Leukoeyten aufzenommen; diese stellen daber eines 
mittel dea Korpers gegen die Infektion mit Mikroorganismen dar. Die Aufnahme 
organismen durch die Leukocytan wird begtinstigt durch gewisse im Plasma vo 
Stotte, die ala Opsonine bezeichnet werden. -- Ober die Bocinflasenng der 
(beobachtot an der Anfnahme von Kohlepartikelchen in die Zollen) durch verschic 
Einflisae vgl. Hamburger, Besonders bemorkenswert ist, daB dic Hinznfign 
CaOl-Mengen das phagocytire Vermégen erheblich stoigart. 


Die Zahl der Leukoeyten (Technik pag. 39) betriigt 5000 
in 1 mm*, schwankt also in weiten Grenzen. Nach Al. Schm 
unmittelbar nach der Entleerung des Blutes ein ete Teil der Li 
zugrunde gehen, so daG sie also in dem noch kreisenden Blate 
zahlreicher als in dem entleerten wiiren; diese Angabe wird ab 
dings von den meisten Untersuchern hestritten (.M. Loowit™®), 


Kino Vermohrung der Lonkocyten tiber die physiologiseho Maximalzubl y 
gehender Art wird als Lenkocytose bexeichnot; unter normalen Verhiiltnissen 
sich dabei xtets um cine Vermehrang der polynokleiiren neatrophilen Lenkoc 
derartige physiologische Leukocytose kommt vor wiibrend der Verdanun, 
Gulland w. Paton, Brasch**); nach kiirperlichen Anstrengungen (Sch 
Zunt=""); nach der Massage (Kkgren*); fornor in goringom Grade in den to 
der Schwangerschaft, wihrend der Geburt stark zunehmend und im Wochenbet! 
wieder xnrilekgehend (Haht™, Zangeneister uv. Wagner ™); bolum Nongoboron 
nach Anfnahme einer groBon Anzahl yon Stoffen in don Organismus, 2. B. Chinkn, 
‘Torpentinél, Albumose, Nucloinsiiure, Milz-, Thymus-, Knochenmarkextrakt, Ba 
Stoftwechselprodukts dorsolben ua. (Chor pathologische Leukoeytose vgl. § 18. 
in ciner bestimmton Provinz dex Gofiiisystems kann die Zaht der Lenkocyter 
wechseln. So ist regelmigig die Zahl derselben in den peripheren Geftien grdBer 
zentralen (Goldscheider u. Jakob ™), Lokale Erwiirmang vermindert, Abkihlun 
in den Gefen des betreffenden Kérperteiles die Lenkoeyten (Winfernit=** a. 
in den durch die Kilte kontrabierton BintgefiGen angebalten werden. 

Eine Verminderung der Zabl dor Lenkocyten unter dic physiologische | 
wird als Hypoleakocytose oder Lenkopenlo bozolehnot. Durch dio Kinw 
Rintgonstrahlen kann eine hochgradige Abnahmo der Leukocytenzahl bewirh 
das Bint gunx lenkocytenfrel gemacht worden (Heinecke™, Helber u. Linger 

. Sick); das Znstandekommen dieser Wirkung ist noch nicht villiz aufgekl 
© dio Rontgenstrahlen wirken Injektionen von Cholin (beim Kaninchen) ( 
Lichtenberg). Nach Injektion von artfremdem Serum tritt cine rapide Ab 
Leukocyten ein, nicht nach Injektion von urtgleichem Serum (Hamburger uv. ¢. 
anf diesos Stadinm der Leukopenie folgt immer eine Leukocytose (Grisshammer 


















Die Blntpliitteben. 


Il. Die Blutplattchen oder Thromboeyten (Hayem®, 

. Fig. 10); farblose, klebrige Scheibehen von wechselnder Grobe 
By) und yerschiedener, leicht veriinderlicher Gestalt, meist rm 
th bikonvexe, aber auch bliisehen- oder spindelfirmige 7 
oder mehreren Fortstitzen (Biirker*®*), Im entleerten Blate verlindern, 4 
4 schnell, sie kleben leicht zusammen oder adhirieren am O) 


oder Deckglas, zerfallen in kleinere Partikel und lésen sich 

tf, Sie kénnen auch im circulierenden Blute (Mesenterium des Mont 
nehens, Fledermansfitigel) beobachtet werden. Die Zahl wird sebr — 
eden angegeben, zu 200000 bis 600000 in 1 mm* (Brodie u. — 
130, Pratt)*, Helber '38), 





Wig. 10. 


ui & = 
‘ - = 
@ 6 & = 
: 4 ———— 


e\vs! 





1 rotes BlutkOrper- 
esahon, — 2 die Blutpliticbon unver- 
‘listoben in vervohiedener Ge- 
ter ‘Blutplittchon und Wibria- 
Jeineres Hiufebon zum Toil mute 


{eoloster Patichen mit Pibrintnden. 


td welfion Blutkérperchen senken sich als die schweron Elemente zu Boden, die 
chen als die leichteston stoigen in die Hiho. Berthrt man nach 20—30 Minuten 
pe des Blutstropfens mit einem sehr sorgfliltig gereinigton Deckglas, so haftet an 
‘Tripfchen Plasma, das cine Unmenge yon Blutpliittchen, aber fast keine roten and 
3Intkorperchen enthalt, 

arstellung groBorer Mengen: — Mischt man 10 Teile Blut mit 1 Teil einer 
a Lésung von oxalsanrem Ammonium in 0,7%iger Kochsalzlisung und zentri- 
esos Gemisch, so lagert sich Uber den Erythroeyten eine grauritliche Lage von 
nd Lonkocyten, Ober diogen eine weiBe Schicht, welche fast nur aus Blotplittehen 
ganz oben ist klures Plasma) (Mosen ™*, vel. auch Barker '™), 

Intplittchon kommon nur im Blute der Sduger yor. Bei den anderen Wirbeltier- 
finden sich kernhaltige, farblose, spindelfirmige Gobilde, welche sich im Sbrigen 
wie Blutplittchen yerhalten und vielleicht (?) ihnen analoge Bildungen sind, 


tber die Herkunft und Bedeutung der Blutpliittchen gehen die 
ten noch weit auseinander. Nach der einen Anschauung (Deetjen 49, 
wen'*!, Argutinsky'*, Kopsch™#, Biirker**) sind es priiexistente, 
adige Formelemente des Blutes, sie haben den vollen Wert von 


[818] Pathologisen® veranderangen der roten und weilien Blutkorperchen 


Zellen, bestehen aus Kern und Protoplasma und sind amiboider 
fuhig. Ftir die Zellnatur der Blutpliittehen spricht die Tatsach¢ 
stark atmen (vgl. S.94) und ein polypeptid-spaltendes Ferment 
(Abderhalden u. Deetjen*), Nach anderen entstehen sie als 
rodukte aus den weiben oder roten Blutkirperchen (Arnold ™, Si 
Dereisich u, Heim'*?, Schilling \**). 
Die Blutplittchen stehen in naher Beziehung zur Blutg 
(vgl. pag. 78), diese ist an den typischen Zerfall der Blutpli 
kniipft. Nach Birker® ist die schlieBlich gebildete Fibrinmenge 
von der Menge der zerfallenen Blutplittehen; alle Momente, ' 
Blutgerinnung beeinflussen, wirken in entsprechendem Sinne au 
fall der Blutpliittchen. Die entstehenden Fibrinfiiden setzen si 
noch erhaltene Blutpliittchen und zusammengeklebte Hanfen dei 
(Fig. 10, 6 u. 8), zwischen dem Zugrundegehen der Pliittchen unc 
stehen des Fibrinnetzes besteht ein deutlicher Parallelismus ( 
IV, AuBerdem kommen im Blute regelmiBig Formelemente kleinster Ari 
staub oder Himokonion (H. F. Maller), Ex handelt sich dabel zum Toil 


produkte von eb be und Blutplittchen, zum Teil nm feinst vertoilte, 
mann, Neisser n. ining), 


18. Pathologische Veriinderungen der roten und 
Blutkérperchen. 


1, Rote Blutkirperchen. — 1. Die Zahl dor roten Blntkiirperchen w 
Blatverluste vermindert, sowohl absolut, als auch in der Volumencinheit, di 
an Flissigkeit durch Kintritt von Wasser aus den Gewoben schnell gedeckt wir 
wird dann durch erhihte Nenbildung das normale Verhalten wiederhergostellt | 
Hine linger dauernde Verminderung der Zahl der roten Bintkirperchen resp. 
logisch wichtigsten Bostandteiles, des Hamoglobins, wird als Antimie bozel 
kann es sich ontweder um eine Beeintrichtigang der Blutbildung oder um ¢ 
der normalen Kinschmelzung der roten Blutkirperchen oder endlich um ci 
Zerstirung derselbon handoln; bisweilen migen unch mehrere dieser Moment 
wirken. Bei der Chloroso (Bloichsucht) ist das Wesentlichste cine Beeintri 
Blutbildung: os findot sich dabei oine mehr oder weniger starke Vermin’ 
Himoglobins, die Zahl der roten Blutkiirperchen kann dabei normal sein, 
sie aber ebenfalls yermindert. Im Gefolgo anderer Krankheiten troton hiufly 
sekundire Animien anf, #0 nach schweren Infektionen (Syphilis, Malar 
lose ete.), Vergiftangen (Blei), bei malignen Tumoren, nach biufg wiederholt 
und nach vielen anderen schweren Erkrankangon. Bel der sogenannten p 
Aniimie, die schlieBlich xam Tode fMhrt, iat die Zahl der roten Bintkirperchen 
lich stark vermindert, sogar unter 1 Million; ang noch unbekannten Griinder 
cine starke Zoretirang der roten Blatkdrporchon statt (Rickbildongsforn 
produkts im Blnte, Mikro- und Poikilocytom, s. unten), daboi ist die Nenbil 
erhoblich gosteigert (Ausbreitung des roten Knochenmarks auf die ganze Linge 
knochen (vgl. pag. 49), Auftreten kornhaltiger roter Blutkorperchen im Blute 
Nenbildnng gentigt offenbar nicht, um dio Wirkung der die Blutkirperchen 
Momente aufzoheben. 

Kine Vermehrung der Zohl der roten Blatkirperchen.in der Volamen 
sich bei Krankheiten, bei denen das Bint durch Wasseryerluste wassorirmer 
manchen Herafehlern, nach Durohfallen, nach reichlichem Schwitzen, Rine beso 
heit, bei der die Zah! der roten Blutkérperchen danernd anf 7—8 Millionen 
vermehrt ist (daneben Milstamor und Cyanose), iat erst in nouerer Zeit unter 
Polyoythaemia rubra oder Erythrocytosia bosehriebon worden und in 
noch vollig unklar (Senator, Hirschfeld ™), 


2. Flirbbarkelt, Grife und Form, — Die normalen roten Blutkirp 
mocyten) firbon sich mit sanren Farbstoffon (2. I. Kosin), sie werden als ortho) 
bezeichnot. Hauptalichtich in aniimischom Bluto kommen rote Blntktrperchen + 
zn basischen Farbstoffen Affinitit haben, sie werden als polychromatise! 
Nach dor GréBe unterscheidet man Mikroeyton (Durchmossor unter 6 1) 





Pathologische Veriinderungen der roten und weiden Bintkirpereivesn, 


‘arehmesser fiber 9 bis 151); beide Arten kommen bei Animien ear 
verten besonders bei perniciiser Aniimie. eerala ies rote. re 
fees bezeichnet; ihr Anftroten im animischan Blate kann ein 
« boginnender Regeneration darstellon. Rrythroblaston von dor GriBe eines 
werden sl “Sh solche von erhoblich 


eee die Korperchen Sa 

er Yorbrennangshitze Tripfehen yon den Kérperchen loggeldst, fhnlich man 

kroskopischen Pritparate unter Einwirkung der Hitze (pag. 40) beobachtet, Zerfall 
tkorperchon in viele derartige Tropfehen ist bei verschiedenen Er) 

hoftigen Sumpfilebern, beobachtet worden, Aus den Brochsticken gehen dem 

mde dunkle Pigmentpartikeln hervor, die zunichst im Blnte schwimmen 
mie). Die Lenkocyten nehmen einen wil dieser Partikeln in sich anf Evy 
erscheinen sie in verschiedenen Goweben deponicrt, namentlich in der Milz, der 

4 Gehirn und Knochenmark. 


. Parasiten. — Bel der Malaria entwickol sich Parasiten, die zur Ordoung 
rozoen gehiron, innethalb der roten Blatkirperchoa (Lacerun 1880); sie werden 
n Stich von Micken (Anopheles) tibertragon. — Boi Rickfallfinbor (Typhas 
ts) tindet sich eine Spirachaete (Obermeier 1873) im Blue. — Trypanc- 
sind Blutparasiten, dio in zahlroichen Arten bei Tieren und Menschen im Tlutplasina 

worden sind; sie sind xum Teil unschidlich, 2um ‘Teil yerursichen sie hate 
+ Zn diesen Erkrankungen gebiiron dio Tsetsokrankhoit der Rinder nnd 
crankhoit, 


| Die weifen Blutkirperchen — sind bei den moisten Infektionskrankhelten 
trt, so zB. bei Pneumonie, Erysipel, Dipbthorie usw. Fine Ausnahme machen der 
izierte Typhns abdominalis und dio Masern, bei denen die Zabl der inane 
dort ist. — Wenn bei Porityphlitie die Zahl der Lonkocyten steigt bis 
30000, so ist dies ein Zeichen dafir, dal AbscoSbildung eingotreten umd Sn 
Bingreifon angozeigt ist (Curachmann'®, Federmann"*); ebenso tindst sich Ver- 
dor Leukoeyten bei Kitornngen der inneren weiblichen Goschlechtsorgane (J/Mt= 
). — Bei dor pathologischon Lenkocytose handelt es sich hing um eine yorwie 
ormehrong der polynneleliren noutrophilen Lenkocyten, doch kommt anch zuweiles 
‘ung der Lymphocyten yor. Boi Asthma bronchiale, manchen Hantkran ke 
sowie bei Trichinosis sind die cosinophilen Lenkocyten vermehrty bei Tnfek- 
akheiten dagegen (mit Ausnahme des Scharlach) kinnen sie anf der Hihe der Krank= 
a verschwinden, im nachher wieder anfzntreton, ihr Wiedererachoinen kann dana 
| als ein glinstigos progostisehes Symptom anfgefibt werden. 
folder Leukimie findet sich eine exzessive Vermehrung der Leukocyten (300.000 
000), das Verhiltnis der roten za den weifen Kirperchen kann dabei 2:1 werden. 
sind die Erythrocyton vormindert. Bei der lymphatischen Leukiimie finden 
Binte neben den Erythrocyten fast our Lymphocyton, die granulierten Lenko- 
nd stark vermindert. Boi der myelogenen Loukiimio finden sich neben dem stark 
ten polynucleiiren nentrophilen, eosinophilen und basophilon Lenkocyten zahireich® 
+ weile Blutzellon, unreife Zellen, welche normalerweise im Knochenmarke yer- 
jetzt aber in die Binthahn gelangen. 


Hlykogonrenktion innerhalb dor Loukocyten (Czermy!™) findet sich bei schweres 
a und Lenkimie (Hofbaucr!™), sowie nach Rinspritemng von Kultnren und Toxinen 
terien (Kaminer?®), 








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9. Chemische Bestandteile der roten Blutkérperchen. 
Das Hiimoglobin.* 
Der Blutfarbstoff — Hiimoglobin (abgektirzt Hb) der roten Blut- 


erchen bedingt die rote Farbe des Blutes; er findet sich auSerdem 
in dem Muskelgewebe. Das Hiimoglobin ist cin zusammengesetzter 





Ls) HMimoglobinkryatalle. 


Wig. 31. 





MAmoglobinkrystalle nach Bridos?: 1. and 2. Krystalle aus friachem Mensehonblat, — 3, 
om Hlat ciner monseblichou Leiehe. — 4. Kryatalle aus menschlichem Milerononblut. — 6. 
ane mensebtichom Nabelechuurblut. — 6. Krystalle aus Eiebhorneheablat, 





Das Himogtobin. 


Blut vom Schweine (und Rind eingeklammert) nach Hijfner* C 
66) — H 7,38 (7.25) — N 17.43 (17,70) — 8 0.479 (0,447) — Fe 
pole 19,543). — Es kommen auf 1 Atom Bisen 2 Atome 
wefel beim Pf (Hitfner*, Zinoffsky®), 3 beim Hunde (Jaquet*), 
ow den BR ty des menschlichen Hb ygl. S.62. Flr das 
vicht des (Rinder-) Hamoglobins ergeben sich nach 
thoden Werte von 16321 bis 16721 (Hiifner u, Conse 
ich in Wasser, beim Erhitzen koaguliert es unter Zersetzung. Das Hiimo- 
bin gehért zu denjenigen Kiweibstoffen, welche krystallisieren (Fig. 11); 
allen Vertebratenklassen, bei denen man die Krystalle te 
stallisiert es im thombischen Systeme, zumeist in rhombischen Tafeln 
r Rrieaecg heim Meerschweinchen in rhombischen Tetraedern (Rollett 
v. Lang®), Das Eichhiérnchen weicht ab, indem dessen K: 
ca, ae Tafeln darstellen; nach UAlik? kann das Himoglobin aus 
tedeblut auGer in den bekannten rhombischen Krystallen auch in 
agonalen holoedrischen Krystallen, und zwar in sechsseitigen i 
alten werden. Die Krystalle scheiden sich bei siimtlichen Wirbel- 
Klassen aus beim langsamen Verdunsten des lackfarbig ge 
chten Blutes, jedoch mit verschicdener Leichtigkeit. 


Es kommt auch vor, daB das Hb im Innern cines Iutkirperchons ‘krystallisieet 
idenreich*), 

Die Himoglobine der verschiedenen Tiere sind chemisch versehiedene Kérper, doch 
wahrscheinlich der firbende Bestandteil des Hiimoglobins, das Hiimatin, fberall dieselbe 
slang, die Verschiedenhelt der Hiimoglobine ist vielmohr bedingt durch die Artversehieden- 
des ciweibartigen Bestandteils, des Globins. Die Krystallisation gelingt um so lelelter, 
chwerer lslich das betretfende Hiimoglobin ist. Am wenigsten Wslich ist das Hb von 
rachweinehen and Ratte, etwas leichter lislich das von Pferd, Hund, Katze, am leiehtesten 
ch das yon Kaninchen, Schwein, Rind, Mensch (Harker"). 


Darstellung der Hiimoglobinkrystalle’, 

1, Nach Rollet'*, — Delibriniertos Biot, durch Gofrieron und Auftanen taok: 
acht, gieBt nian in eine flacho Schalo, deren Boden nar 1"/, am hoch darait 
|, und IABt ganz lingsam am kilhlen Orte abdunsten, wobei die Krystalle sich abecheldan. 

2. Nach Hoppe-Seyler"'. — Defibriniortes Blut wird mit 10 Volumina einer Koch 

Glonbersnlelosung (1 Vol. konz. Lisnng nuf 9 Vol. Wasser) vermischt und absotzen 
seen, resp. abzentrifugiort. Der dicke Blatkirperchen-Bodensatz wird mit etwas Wasser 
inen Glaskolben gespiilt and so linge mit gleichem Volumen Xther geschiittelt, bis die 
korperchen sich anfiisen, Der Ather wird abgehoben, die Lackfarbe kalt filtriert umd 
4), Volunen kalten (O°) Alkohols versetet; bei —S°O li8t man einige Tage stehen. 
nun reichlich gebildeten Keystalle konnen aaf dem Filter gesammelt end xwischea 
Bpapier abgepreBt werden. Durch ganz allndhliches Binwirken des Atkobols auf die 
(isung (durch Fintreton desselbes in elnen Dialyeator) erzielte Lowdois Krystalle von 
fon Millimetern Linge. — Offringa " vermeidet bei der Herstellung der Hb-Krystalle 
Rinwirkang ¢hemischer Substanzen, durch che das Hb verindert werden kénnte, 
m er dio ubzentrifagierton roten Blatkirperchen mit Infusoricnerde mischt und mit der 
taulischen Presse auspreit; die so erhaltene hoch konzentrierte Hb-Lisung wird dans 
a Abkithtung oder noch weitere Konzentricrang zum Krystallisicren gebracht. 

B. Gecherdien ® ersielte die gridten Krystalle von mebreren Zentimetern Sag 
trch, da® er dofibriniertes Blot, welches 24 Stunden an der Luft gestanden butte, im 
re Glasrobrehen cinschmolz und mehrere Tage bei 37°C antbewahrte. Nummehr anf 
t Glasplatte amsqebreitet, It das Blat die Krystalle anschieBen. 

Das vom Rlategel gecangte Blet bestebt, wenn man ea ach etwa 14 Tagen ams dem 
en des Egels beransdriickt, ane zablloson Hamoglobinkrystallen (Budge™). In dem von der 
dezecke (Ixodes ricinus) gesaugten Hint eatstebt anter Auftisnng der Bintkirperchen, Rediak- 
des Hb and Bindickung ein Krystallbroi von sauerstoffireien Hb-Krystallen (Gratzner ™). 

Die Hb-Krystalle sind doppelbrechend and pleochroitiseh, d. h. 


zeigen bei der Betrachtang im polarisierten Lichte bei ve 


teide (vgl. pag. 15), Seine Se etches Pabsmmeneabneye Fclaafi 









(6194, WANUITALIVE Bestimmung des Hiimoglobins. 


Orientierung hellere wd dunklere Farbungen. Sie enthalten 3° 
Krystallwasser und werden daher bei desselben unter Ver 
zertriimmert. Sie Wisen sich in Wasser (aher bei verschiedenen 4 
sebieden a leichter in diinnen ‘Alkalien. Unlvslich ist Hime 
‘Alkohol, Ather, Chloroform, Fetten. Hiimoglobin dreht das polarisi 
nach reehts (Gamgee u. Croft Hill), 


Dnrch den Krystallisationsprozef scheint das Hb solbst eine innare Ver} 
erfahren. Vor der Krystallisation diffandiert es nicht als echte ge 
zersetat os nie O,, Ans den Krystallen hingegen wieder anfgeliist, dj 
xering, xersotat nicht und wird unter dosson Hinwirkung solbst entfirbt. 
Himoglobin in traded Zustande sich in verschiedener Hinsicht anders cans 
unversehrten Blutkorperehen, so glanbte slopgh-Soptie daB das 0,-Hb und da 
Hb innerhalb der Erythrocyten mit Lecithin verbunden sei als Arterin a 
Nach H. Kobert® kann Arterin und Phlebin auch krystallisiert erhalten worden 
scheidet dieso Krystalle strong von den Himoglobinkrystallon, Bohr bexeich 
verlinderten Blutfarbstoff der roten Blntkirperchen als Hiimochrom, zum Unte 
dem ans ihm dargestellten Himaglobin. 


Quantitative Bestimmung des oglobing, ' 

1. Dio genanosten Resnitate gibt die von Vierordt'® und Hafner’ an 
spektrophotometriache Methode, ‘Tritt Licht einer bestimmten Spektralr 
te Losung eines Farbstoffes hindureh, so ist din darch dic Absorption bowirkte 
dor Lichtintensitit, nusgedriickt in Bruchteilen der urspriinglichen Lichtintensitiit, 
Dieke und Konzentration der absorbierenden Schicht immer gleich grof, mnabhii 
‘ob das durehfallende Licht stark oder schwach ist. Als Extinktionskooff 
xeichnet man den Wert der Schichtdicke, wolehe das Licht durchstrahlen mnb, 
Zehntel seiner urspriinglichen Intensitit abgeschwiicht xu werden. Dieser Ex 
kooffizient einer gofirbten Filssigkeit fr einen bestimmten Spektralberi 
Konzentration der Flissigkeit direkt proportional, das Verhiiltnis zwischen Ki 
und Extinktionskoaffizient oder das Absorptionsverhaltnia ist also konata 
Absorptionsverhilinia ¢ines Farbstotfos fiir einen bestimmten Spoktralbezirk | 
kano mun mithin ang dem beobachtoten Extinktionskoeffizienten ciner Lisung « 
stotfes dio Konzontration desvelbon berechnen. (Wegen der Dotails der Metho 
Origa von Vierordt™, Hifuer™, ¢. Noorden™, Otto, Albrecht.) 

2. Zu ktinischen Zwocken dienen die colorimetrischen Methoden. N 
Seyler™ wird die xu antorsuchende Fiiissigkeit mit cincr reinen Himoglobin 
bekinntom Gehult verglichen und go lange mit Wasser verdiinnt, bis sie gon 
Farbe hat wie dio Vi ichstliissigkeit; aus dem Grade der Verdfinnung ergib 
der Gehalt an Hiimoglobin, Zweckmibig werden die beiden a vergleichenden F 
mit CO gesiittigt (vel. das von J. Plesch™ angegebene Chromophotometer um 
keilhimoglobinometer) 

Das Himometer nach Frisch! *-Miescher® (Fig. 12) bostabt ans einem 
Objekttisch aufunstellenden, in xwei Halfton geteilton Cylinder, Dio eine Hilft 
Wasser geftilt, die andere mit einer Verdfinnnng des xu nntersuchenden Blntes, 
winer Mischpipette, tihnlich wie bei der Blutkorperchenzihlung, hergestellt wird. 
rot gefirbten Léisung vergleicht man die Parbo einos unter dem reinen Wasser do 
Miilfte durch eine Schranbe vorbeigefihrten roten Rubinglaskeiles und ; 
roten Farben gleich einzustellen. Die Belenchtung des Blutwassers und des 
geschieht von unten durch Lampenlicht Der Ginskeil triigt dic moet 
Himoglobingehalt in Prozenten des normalon Gohaltes angeben, x 
das untersachte Blut enthalt 80°, des normalen Hb-Gohaltes ( Veillon*?, Fr. 7 

Bei dom yon Gratzner™® angegebenen Hiimometer bofindet sich die Bh 
einem Glaskell. Mittelst oines horizontale Schlitze tragenden Schiobers aus 
wird diejonige Stelle des Kellos anfgesucht, welche die gleiche Furbo xeigt wi 
gleichsfarbo (Pikrocarmin-Leimplatte oder bosser rotes Glus). 

Das Gowwerssche*® Himoglobinometer besteht ans zwei gleich kulilei 
ribrehen, von denen das cine eine Pikrocarmiolisung enthillt, deren Farbe gena 
1°/igen Léxung normalen Blutes entspricht. In dem anderen Robrchen wird eine 
Menge Blut so lange verdiinnt, biv seine Farbe der der Vorgleichsfarbe gleich i 
yon Sahli®* angegebenen Modifikation dieses Apparates dient zum Vergleich ein 
Wgung, welche salzsanres Hamatin enthilt; das 2a unteranchonde Blut wi 
zehnfachen Menge "/,, Normal-Salzsinre versetat, wodurch der Bintfarbstoft ebenfe 
saures Hiimatin fibergefihrt wird, nod mit Wasser solange verdinot, bis es die 




















Quantitative Bestimmung dex Himoglobias. 


die Vorgleichslisung hat. Das Sadlische Hiimometer hat yor den anderen auf gloichem 
tip bernhenden Apparaten den grofen Vorteil, da chemisch und farblich yollig 
che Flissigkeiten miteinander yerglichen werden: es kann daher auch tei jeder 
bigen Belenchtung benntzt werden (vgl. Biirkér™), 

Die Himoglobinskala von Tallquist™ besteht aus einer Reihe roter Paplere you 
tigender Farbintensitit, entsprechend 10—100%, des normalen Himoglobingebaltos, Der 
ntersnchends Blutstropfen wird auf einem Stick Filtrierpapier aufgafangen und der ent: 
mde Fleck mit der Skala verglichen, 

Gaerinera™ Hiimophotograph* beruht daranf, daB cine Losung von O-Hb die 
ographisch wirksamon Strahlen um so stirker absorbjert, je konzentrierter sie ist. 
rschiode im Hb-Gehalt, die sonst nicht wabrnehmbar sind, werden durch das photo 
hische Verfahren dentlich erkennbar. 

3. Chemisch kann man das Kison in einem gomeskenen Quantum Blut bestimmes 
darans den Himoglobingehalt berechnen. Der Risengehalt des mensehlichen Hb betriigt 
den neuosten gut tbereinstimmenden Analysen Butterfields** 0,336°),. Die Hi 
shiodener Vierarten haben wahrscheinlich gleichon Fe-Gehalt. — Jollcs*® hat einen amt 
m Prinzip bernhenden Apparat (Ferrometer) xar Himoglobinbestimmung angexeben, 








Pig. 13; 





Hamomoter nach Fieischt-Mlercher. 





Der Hb-Gehalt des Blutes betriigt bei gesunden Erwachsenen 13—14%),. 
nen und Kinder haben einen geringeren Hb-Gehalt als Minner, nach 
dane hetriigt der Hb-Gehult bei Frauen 89, bei Kindern 879/, des 
nalen Hb-Gehaltes erwachsener Miinner. Beim Neugeborenen ist in der 
on Lebenswoche der Hb-Gehalt erhdht: 139°/, des normalen; er sinkt 
a und betriigt von der zweiten Hiilfte des 1. Lebensjahres bis zum 
Lebengjahre nur 80—90°/, des normalen, vom 25.—45. Lebensjahre 
°/o; im hoheren Alter sinkt er wieder unter die Norm (Leichtenstern*, 
rlin®). Mit dem Hb-Gehalt geht die Zahl der Erythroeyten ziemlich 
lel (Schwinge*®). 

Dor Hb-Gehalt des Tierblutes schwankt bei den verschiedenon Arten von 10-—17%y 
pag. 84), 














[$20] Spektroskopische Untersuchung. 


betriigt es 95,5%/o aller organischen 
Erythrocyten weniger). 

Im Hunger ist das Himoglobin widerstandsfihiger als die ibrigem festan 
teile des Blutes (Hermann u. Grol), — Ober das Verhalten des nti 
logischen Verhiltnissen vgl. pag. 55 (Chlorose). 


Tn feuchten Erythrocyten fand Hepa Sehr io 1b, a 
in den sen 


20. Sauerstoffverbindungen des Himoglobins: Oxyhi 
globin und Methimoglobin. Spektroskopische Untersuchu 
Der Spektralappurat (Fig. 13) besteht aus— 1. dem Kollimator-Robr 4 


an dem einen Ende den verstellbaren Spalt 8 triigt, am anderen Ende die Samm 
Der Spalt betindet sich im Brennpunkt der Linge; die yon einem Ponkte des Sp 


Fig. 18. 





Schema den Spektralapparates, 


gehenden Lichtstrahlen werden also durch die Linse parallel gemacht und treten 
2. das Prisma / ein, durch welches die Strablen gebrochan und in Strahlen yer: 
Wollenliings, entsprechend den Spektralfarbon, zerlegt werden, Diese gelangen in 

Fernrohr B, Die Lingo B dieses Fernrobrs vereinigt alle Strahlon gleicher Wolle 
einem Pankte, alle roton Strablen in ry alle violotten ine, So entsteht in r ein} 
des Spaltos S, in ¢ ein violottes, dazwischen befinden sich die Spaltbilder dor xwi 
und Violett Mogenden Spektralfarben. Dio Gosamtheit dioser Spultbilder ist das 

rv; os wird durch die Lupo / betrachtet. — 4. Das Rohr ( enthiilt an dem « 
die Skala G, on dem anderen dio Sammellinse 4. Die von cinem Pankte der § 
gehendon Lichtstrahlen werden durch // parallel gegen die Fliiche 4 ¢ des Prismas 

von dieser in das Fernrohr / reflektiert und durch die Linse 2 im Brennpunkte 
So entsteht an derselben Stelle wie das Spektram r—r cin Bild der Skala G, we 
dem Beobachter zogleich mit dem Spektram gesehen wird. 

Belouchtet man den Spalt S mit monochromatischom Licht (x. B. Natriumtls 
ontsteht an Stelle der kontinuicrlich nebensinandor tiegonden Spaltbilder r-—v de 
Lichtes nur ¢in Spaltbild in der Farbe des monochromatischen Lichtes, # B. 
Natriumlinie. 

Bringt man vor den mit weifeom Licht belenchteten Spalt S cing Farbs 
(x. B. Hiimoglobinldsnng), 80 Lilt diese nur einen Teil der Strablen des weilon Lich 





t Das Sauerstof-Himoglobin, i 


erscheint daher dem Beobachter als dunkle s Absorptionslinve 
Wird der poe jap eae mit Sonnenlicht beleuchtet, so zeigt das Spektrum oi 
aht von danklen fersche Linien) in gonan bestimmter Lage 
arben, nach win ii Sane og Ne oda, Densch 





or zweite, Es sind daber Prismen- und Gitterspektren nicht ohne weiteres 
ees Spektren in Fig. 16 sind Prismenspektron, die in Fig. 17 sind Photographi 
ach Git tren, 

Fine grofe Bedontang hat die photographische Registricrung der Spektralerscheinmng 
pwonnen: Spektrophotographie (Rost, Franz n. Heine) ‘Durch die photographise 





Pig, 14. Fig. 18, 























BO D Eb F G oh abo D Eb F G b 


‘Dis Abeacpalonenyaizs dee OviEib UPig. 18) sad Gee mnatielen Hs (Wig. 16) bel etatsesiion eau: 
tration. Me Dicke der nnterrochton Floesigkoltesed je Buebstaben unton bedouten 
Gla Frmamheferichen: Ldatea s dle Sablen war Bolte Sea Proseaiguhelt der ZesUngesn a 
ich Roll 





nfnahme gelingt os, auch dio im unsichtbaren, ultravioletten eile des 3} 
slogenen Absorptionsstreifon zu beobschten, dio gerade bel sebr starker Verdfinnung @ 
lutlésungen anftreten, wenn dio im sichtbaren Toile dos Spektrnma gelegunen Absorption 
reifon bereits verschwunden sind (vgl. pag. 65). 

1. Das Sauerstoff-Himoglobin oder Oxy-Himoglobin =0,-H 
htsteht sehr leicht, wenn Himoglobin oder Blut mit Sauerstoff oder Lu 
1 Bertihrung kommt; sehilttelt man Blut oder eine Hiimoglobinlésung lel 
aft mit Lu i, so wird fast alles yorhandene Himoglobin in Oxy-Hitox 
lobin verwandelt. Das 0,-Hb ist eine chemische Verbindung: 1 Moleki 
limoglobin bindet 1 Molektil Sauerstoff = 0,; 1g Himoglobin bind 

84cm? Sauerstoff (Hifner**), Doch ist der Sauerstoff im O.-Hb nich 
dst gebunden; das O,-Hb ist eine sog. dissoziable chemische Ve 
indung (vgl. § 30). Der Sauerstoff wird daher schon durch solehe Mitt 
usgetricben, welche physikalisch absorbierte Gase entbinden: dure 
intgasen unter der Luftpumpe, Durchleiten anderer indifferenter Gas 


Tafel I. 





1 is 
Ae 589 

At 550 
damec 

2. ‘ 
A+ 596 


| 
aie tsnenstaben H—A Gifagebestimmang der Absorptionsstreifen jedeamel « 


Vreham 2 Catnrne ah aie 


Jerrocyamd xn normatem 1st0t Ne 


0 





1. Wellenlingenskala i Agensk: 






in 00,-freiem 


Bluthisang 1:70 ser. 





in CO Shalt 


3. in 13109 Wasser. 
ioe 1150 in alkalischer 
Liisung, 
bmg 1:80. 
I Munivaeuvuueaun 
Bb oe 1:200 
hey 1:300 
VI. Hamochromogen (durch Behi 
normalem "Blut init ,Natronlange 
von Schwefelammoniam herg 
ie Oe 1 








6.4 1:800 
ng 1: 100 
om 1:1000 i pit 1 
104 s 1:1500 
VII. Himatoporpbyrit 
Eb 1:2000 





‘wtrocknet ond 
konzentrierter 
sfelsiiure yer- 
\. 

1, weiter 


nad mit Py 
alinoh 









Spekira des Blutfarbstoffin Wellenlfingon der Lichtstrahlen in Milliontel Mi 
die Buchstabon A—K dikyebestimmung der Absorptionsstreifen jedesmal n 


[$20] Das osurrstol-Himoglobin. Das Methimoglobin, 


and Erhitzen bis zum Sidopsaks 30). Chemiseh kann dem 0, 
Sanerstof? entzogen werden durch reduzierende Substanzen, z. B.S 
ammonium oder Stokes *> Reagens (Lisung yon weinsauren 
oxydulammon; stets frisch zu bereiten darch Auflisung yon etwa 
sulfat in Wasser, Zusatz von Weinsiiure und darauf yon Ammo! 
zor alkalischen Reaktion): es entsteht reduzier tes (gastreies) Hin 
Schiitteln mit Luft bedingt sofort wieder Bildung von O,-Hb. 

Lisungen des O,-Hb sind scharlachrot, Lisungen des re¢ 
Hb violettrot und dichroitisch. d. h. bei auffallendem Lichte di 
bei durehfallendem grtin (vgl. 5.33). Bei der spektroskopischer 
suchung zeigen konzentriertere Blutlésungen Absorption des ganzen 
Teils des Spektrums; bei fortsehreitender Verdtinnung der Lésun 
dann die charakteristischen Absorptionsbiinder auf (vgl. Fig. 14), 
zeigt in etwa 1 bis }/,°/, Blutlisung zwei Absorptionsstreifen 
und Griin (Hoppe-Seyler* 1862) (Fig. 16.71, 17. 1); reduzier 
an Stelle der biden Streifen des O,-Hb einen breiten verwas 
Absorptionsstreifen (Stokes*” 1864) (Fig. 16. 2., 17. JD), 

Bel zunchmendor Verdinnnng der Blutlisung werden die beiden Absorptic 
‘les O,Hb immer schwichor und vorsehwinden scblieBlich ganz. Daftr tritt , 
Violett cin durch die Spektrophotographie nachweisbarer, ebenfalls fir O-Hb | 
stischor Streifen anf (Soret, Grabe*, Kobert**); durch diesen Streifen konnte 
in der Vordiinnung 1;000 nachgewiesen worden (Fig. 17. J.) (Kost, Franz u 

Wonn die Rednktion des 0,-Hb xa rednziertom Hb durch Schwefelammo, 
xenommen wird, so tritt anBer dem charaktoristischen Streifen des reduzierten Ht 
Streifen im Orange auf; er rihrt von einer Bildung von Sulfhiimoglobin her, 

Sotzt man zu Blat xaerst einige Tropfen einer 40°/, Formaldebydlisang 
Schwefslammoninm, 80 erhiilt man einen sehr scharfen und danklen Streifen von radu 
(Tollens™), 

O,-Hb findet sich im kreisenden Blute innerhall der rote 
korperehen: es kann durch die spektroskopische Untersuchung des Kar 
ohres oder der diinnen Hautschichten zwischen zwei aneinander, 
Fingern nachgewiesen werden. Werden Tiere durch Erstickung 
so wird aller Sauerstoff des Blutes an die Kirpergewebe abgege 
daB nur redaziertes Himoglobin in den Gefiiben angetroffe 

Umschniirt man die Basis 2woier Finger bis aur Oircnlationsunterbrochung 
man bel der spektroskopischen Untersuchung der roten Hantsinme, mit welchen 
berdhren, da® das Q-Hb alsbald in redaziertes Hb ubergeht (Vierordt™). Binwi 
Kilte verzigert dieso Reduktion; im Jngondalter, withrend der Muskeltitigkeit oder 
drtickter Atmung, meist anch im Ficber ist sie beschlennigt (Dennig*), Auch eins 
Horz wirkt reduzierend anf 0,-Hb (Handler**). 

2. Das Hiimoglobin bildet mit Sauerstof¥ noch eine zweite i 
krystallisierbare Verbindung, das Methimoglobin, Met-Hb 
Seyler®*); es enthiilt ebenso viel Sauerstoff wie das 0,-Hb, aber in 
artiger Anlagerung (Hii/ner u. Otto’, Hifner u. Kiilz®’). Der S 
im Met-Hb ist fest gebunden; das Met-Hb kann daher den ( 
keinen Sauerstoff abgeben. Hierin liegt die Gefahr der Met-Hb 
ftir den Kirper begriindet. Die Umwandlung des 0,-Hb in 
yollzieht sich auSerhalb des Kérpers allmiihlich von selbst, beim 
Jassen des Blotes, bei lingerem Erwiirmen oder langsamem Eint 
Sie kann durch eine grofe Zahl chemischer Substanzen befirdert 
besonders schnell wirkt Ferricyankalium. 

Nicht allein Inckfarbigos Blut, sondern auch das Hh der intakton Bryt) 
kann in Met-Hb umgewandelt worden, . B. dorch chlorsanres Kalium, Antifebrin, 
ta, (auch bei Vergiftungen mit diesen Stoffen). Methiimoglobin bildet sich anch in 
spontan, zB. im blutigen Harne, in sangninolentem Cysteninhalt, in alten Ext 


Landois-Rosomann, Physiotogio. 14. Aut, 


6 Das Kohlenoxyd-Himoglobin. oy 


+ eingetrockneten Blutborken, — Wenn 66—70"%), des O,-Hb in MebHb umgewandelt sf 
rfolgt dor Tod (Dennig™, Bornstein u, Maller"). mre 
Durch chemigche Mittel (Schwefelammonium, Stokessches Reagens) kann d 
‘etHb der Sauerstoff entzogen werden; os bildet sich roduziertes Hb, durch nachteiigticl 
shiitteln mit Luft wird dieses wieder in O,-Hb tibergeftihrt. 
'  Neutrales Met-Hb (hergestellt aus einer neutralen Hb-Lésun 
‘ut + dest. Wasser durch Zusatz von Ferricyankalium) sieht braun at 
Ikalisches Met-Hb (hergestellt aus ciner alkalischen Hb-Lisun 
‘lat +- 0,1°/, Sodalisung durch Zusatz von Ferricyankalium) sieht rot at 
tie O.-Hb. Das Spektrum des neutralen Met-Hb zeigt 4 Absorption 
treifen; der im Rot ist der kriiftigste und charakteristischste (Fig. 16., 
7. V. 2. u, 3.), Das alkalische Met-Hb hat 3 Absorptionsstreifen: zw 
1 derselben Lage wie die Streifen des O.-Hb und dazu einen dritten, ¥ 
fesen nach Rot zu gelegenen (Fig. 16. 4, 17. V. 4) (vgl. Kobert®). 


21. Das Kohlenoxyd-Himoglobin und die (C0-Vergiftung.’ 
Andere Hb-Verbindungen. 


3. Das CO-Hb ist eine festere chemische Verbindung als das O,-H 
3 entsteht, wenn CO mit Hb oder O,-Hb in Bertihrung gebracht wi 
Yoppe-Seyler, Cl. Bernard®, 1857), dabei verdriingt das CO den O & 
2Hb im molekularen Verhiltnis; 1g Himoglobin bindet daber ebenfal 
34 com CO. Es ist kirsehrot, nicht dichroitisch und zeigt im Spektra 
vei Absorptionsstreifen, die denen des O,-Hb sehr thnlich sind, nur etw, 
tther aneinander und zum Violett hin liegen (s. Mig. 16. 11., 17. ZZ). Leie 
tkennt man es jedoch dadurch, daG reduzierende Substanzen, w 
chwefelammonium, Stokessches Reagens (vgl pag. 65) (welche das O,-E 
( reduziertes Hb mit nur einem Absorptionsstreifen verwandeln) d 
treifen des CO-Hb unveriindert lassen, doh. das CO-Hb nicht in r 
uziertes verwandeln (Hoppe-Seyler'*) (Wig. 17. /V.). — Ein ferneres B 
ennungsmittel besteht in der Natronprobe: Natronlauge vom spexifisehi 
ewicht 1,34 zu CO-Hb hinzugesetzt und erwiirmt, erzeugt eine zinnobe 
ote Fiirbang; — zu O,-Hb gefligt, erzeugt sie eine schwarzbraw 
‘finliche Masse (Hoppe-Seyler®*). Die spektralanalytische Untersuchar 
ad die Nutronprobe lassen etwa noch */,, CU-Hb mit */\, Og-Hb ve 
ischt erkennen. 

Weitere CO-Hb-Reaktionen: — Modifizierte Natronprobe: man verdtinnt das Bl 
Wfach nnd swtzt die gleiche Menge Natronlange von 1,34 spex. Gewicht hinzu (Sulkowski® 
( CO-Bint bildet sich eine weiliche Farbung, die bald hellrot wird and beim Steben si 
roten Flocken absetet; normales Blut gibt cine schmutzige schwarzbranne Firbang. 
)Blut bleibt nach Zosatz yon stark golb gefirbtem Schwofelammon und Fssigsinre sch) 
t, normales Blat wird gringrau midfarbig (Katayama), — 4—5faehes Volumen Bh 
etitlosuug 2am Blote zugefigt aeigt bei v,- und CO-Bint cinen dentlichen Unterschd 
‘ulmer*). — Das Blut wird mit Wasser 4mal verdiinnt und 3 Vol. 1%/,iger Tanminiéem) 





h Kostin™ ist diese Probe 4 
ipfindlichsto. Harker ompficblt, die Proben mit 5—10em® 100fich yerdfinnten Blut 
zustellen, Soll die Entscheidung sebnell herbeigeftiirt werden, und braucht dié Probe nie 
agers Zeit anfgehoben xu werden, so figt ar (nach Zaleski) xu em! 100fach verdiinnt 
utes 5 Tropfen konaentriertor Kopfersulfatlisung und kebrt langsam am: OO-Blut gibt eb 
xpurrote, 0.-Blat cine griinliche Farbe: nach wonigen Minuten verschwindet aber dies 
tterschied. Soll die Probo noch nach Mingerer Zeit den Unterschied zeigen, so fligt 
ach Kunkel-Welzel) x0 5.em* 100fach vordiinnten Blates 6 Tropten frisch bereiteter 3°), Tunni 
ing, Kobrt das mit cinem Kork verschlossene Reagenzglas Iangsam um und stellt ¢8 ve 
alossen anfrecht hin: der ontstehende Niederschlag ist bei OO-Biut rosigrot, bal O,-Bi 
amutzigrot bis brinnlich. 





{4 22] Die Kohlcnoxydversitung, Das Stickoxyd-Hiimoglobin. Zerlegung des Himoglo 


seiner groBeren Bestiindigkeit widersteht das 00-Hb Pe Zeit de 
es kann Lepore anch noch in exhnmierten Leichen nuchgewieson werden. 

Die Gasser ably Vi pa — 60 entsteht bei aoa ahs Verbre 
Cx, B. durch yorzeitiges Schlieben dor blakende Iampon; 
Tecthipis kommen 12—28°!, 00 = Doch ist die sgurversifieng aleht voli, 
mit der = OOF argitang (Ferehland w. Vahlen 

Da das CO eine 140mal griBere Afinitit aum Hb besitet als der O (Hi 

so wird durch Atmung Doabieer Loft mehr und mebr der O aus dem Binte 
und es kann natrlich das Leben nnr solange bestehen, als noch hinreichend ( 
enthalten ist, um die fiir das Leben notwendigen Oxydationsprozesse zu unterhalten, 
CO titen den Menschen, ee sae ee ene Es geniigen aber bi 
kleine Mengen OO (*/joo) VIS *{yoq9) in der Luft, um in kurzer Zeit verhiiltnismi 
Mengen CO-Hb zn bi aed #%), Der Tod tritt cin, noch che aller O aus 
verdringt ist (im ungiinstigsten Falle bleibt noch '/, des O im Binte zurlick) ( 
Die Ersebelnangen, die bei der CO-Vergiftung anftreten, sind 2uerst lebhafter Ko 
grofe Unrohe, Anfrogung, verstirkte Herz- and Atmungstitigkeit, Salivation 
Zuckungen und Krimpfe, spiiter troten Unbesinnlichkeit, Mattigkelt, Schlitfrigkeit, I 
ein, Vorlust des BewnBtseins, mithsame riichelnde Atmung, schliefllich villiges Ver 
der Empfindung, Aufhiren dor Atmung und des Heraschlages nnd Tod. Die 4 
zeigt im Anfange Erbdhung bis gegen et a Zebntel Grad, dann folgt Abnahme 
1°C und dariber. Die Pulsschliige zeigen anfangy gesteigerte Knergio, aah 
Puls sehr klein und frequent. Die Alkaleseenz und der Kohlensiurogehalt 
vermindert, die Milchsiiure vermehrt (beim Kaninchen, Araki™, Saiki u. Wal 
Mitunter tritt (bei Hunden nur nach reiehticher Eiweififiitiarung, Strieub ™) Zacke 
anf. Nach tiberstandener Intoxikation soll die Harnstoftausscheidung xanehmen (F 
—In der Leiche ist auffullig die grofe Oberfuiiung der Organe mit fldssigen 
rotem Binte und die Erweiterung der Geftife. Alle Muskeln und Kingeweide habe 
rote Fiirbung: dic Totenilecke sind hellrot. — Die noch lebenden Vergifteten b 
sofort an die frische Luft. Noch wirksamer sind O-Inbalationen. Da durch anhi 
handiang (Durehleiten) des 0O-Hb mit anderen Gasen (namentlich anch mit 0) 
das CO wieder vom Hb getrennt werden kann {unter Neubildung yon 0,-Hb (. 
Zunt=", Podotinski™)), 80 golangt auch im Korper durch die Atmung selon nae 
Stunden das CO gur Ansscheidang; eine Verbronnung des CO 2n OO, kommt ( 
vor (Haldane*). Hochgradige Intoxikation erfordort die Transfusion. 

4, Das Stickoxyd-Hiimoglobin entsteht, wenn NO mi 
Verbindung gebracht wird (L. Hermann), 

Da dioses Gas in Berthrung mit O sich sofort zn Stickstofdioxyd (Untersall 
NO, verwandelt, wolchos anf Himoglobin zorsotzend einwirkt, so muB bei der } 
dos NO-Hb xnerst aller O ang dem Bint und den Apparaten (etwa durch Durchlei 
entfernt worden. Im Korper kann os sich aus diesom Grande nicht bildeo. Das 
gine noch festere chemischo Verbindung als das OO-Hb; os ist mohr blinlic 
und gibt im Spektrum zwei Absorptionsstreifn, ziemlich iihnlich denen der beidi 
Gasverbindungen, aber weniger intensiv. Redozierende Mittel Wechen diese Streifen 

Die drei Verbindungen des Hb mit O,, CO und NO krystal) 
wie das gasfreie Hb, sie sind isomorph, ihre Liisungen sind n 
chroitiseh. Alle drei Gase verbinden sich in molekularem Verhi 
dem Hb und sind im Vakunm austreibbar. 

5, Auch Cyanwasserstoff CNH bildet Verbindungen mit Hb (Kobert™, v. 

6, Ober Verbindungen von Schwefelwasserstoff mit Himoglobin (Su 
globin) vgt Harnack™!, Kobert*#, Clarke a. Murtley". 





22. Zerlegung des Himoglobins. Himoglobinderiv: 


Das Hiimoglobin ist ein zusammengesetzter Eiweibkor 
Chromoproteid (vgl. pag. 15); es besteht aus cinem Eiweibkéry 
Globin (94,09°/, des Hb) und einem Farbstoff (447%, des Hb 
sind Stoffe unbekannter Natar, Zawrow™): dem Hiimatin (bei Z 
von O-haltigem Hb) resp. Hiimochromogen (bei Zerlegang von 
Hb). Das Himochromogen geht durch Oxydation in Hiimatin, ur 


e224 ‘SSUITUE HAMIATOpORPHY FIN, 


Teichmomachne *? Himinkrystalle, selbst aus Spuren yon Blut 
werden kann, so spielt ¢s in der forensischen Medizin eine wicl 
fir den Nach weis von Blut. Trockenes Blut (fliissiges Blut mu st 
vorsichtig, Spee werden) wird auf cinem Objekttriger 
3 Tropten Kisessig und einem kleinen Kérnchen Kochsalz vern 
nach Auflegen des Deckglases vorsichtig erwiirmt, bis sich Blisch 
unter dem Mikroskop sieht man dann die Krystalle (Fig. 18 u. 
selben erscheinen als kleine rhombische Tiifelchen, Biilkehen ¢ 
chen, gehéren jedoch wahrscheinlich dem monoklinischen 
an. Nicht selten haben sie die Form yon Hanfkérnern, Weberschit 
von Paragraphzeichen. Mitunter liegen einige gekreuzt oder in 
In der Krystallform sind die Himinkrystalle aller untersuchten 
tibereinstimmend (Kobert**). Sie erscheinen bei auffallendem Li: 
schwarz (wie angelaufener Stahl glinzend), bei durchfallendem } 
braun. Sie sind doppelbrechend und pleoehroitisch (vgl. pag. 60) 
Dic Himinkrystalle sind bel allen Wirbeltierklassen dargestellt, eben 


Blute mancher Wirbellosen (z. B. des Regenwarms). Auch ans fitalom Bluto las 
horstellen (beim Hfhnchon schon am vierten Tage der Bobriitung, Kobert #3), — 


Fig, 18, Fig. 10. 
vA 
S- = Part Pd rl ot a oe 
¢ * 

Hy VA 6 *, asa ae 

mp ergy 
-“ ee ee fetes ak 
o ES ss dt 
yf me , 8,= ip aA 
eo « , 7 Sn 
- ene ta oy + 

X; ¥\ fart + ‘ AS atin. p 
Haminkrystalle: 1 von Moasehon, — 2 Seohuod, — % Kalb, Hamipkrystalie, darg 
— 4Sehwein, — 6 Lamm, — ¢ Heebt, — 7 Kantnehon, aos Biutspuren: 


phyrin, Blut yerrieben mit Sand oder 'Serkoble oder nach Zusatz mancher Fe 
and AgSalze, yon Atekalk (Lewin 1, Rosenatein *), freiom Jod (1. Kobert 
Himinkrystalle mehr, dagegen stért Formalin die Bildung. der Himinkrystalle n 
Iiminkrystalle sind ‘anlislich in Wassor, Alkohol, Ather, Chloroform, lislich in 
Alkatien. 

Der Kisessig ist orsetzbar durch alkoholische Lisung aller starken Miner: 

organischen Siuren (Teichmann , Wachholz'), das Kochsalz auch durch Jod 

; im letatoron Falle bildet sich das Ahnlicho Bromwasserstoff- oder Jo 
dagegon gibt on kein Floorwasterstoffhiimin (Kobert™*), Bei Verwondu 
atrium IABt sich noch 0,025 mg Blut nachweisen (Strzyzoisky ™), 

Golingt os, aus einom verdichtigen Flecken Himinkrystalle heranstellcn, 
natirlich nur dor Nachweix von Blut tberbaupt geliefert, nicht der Nach 
os sich um Menschenblut handelt, Die Unterseheidung von Menschen- | 
ist miglich mit Hilfe der pricipitierenden Sera (WAlewhut) (vgl. pag. 81). 


Sowohl dem Hiimochromogen wie dem Hiimatin kann d 
wirkung yon Siiuren (Schwefelsiiure) das Eisen entzogen werde 
steht dabei das Himatoporphyrin, Cy, Hy N. O, (nach 4 
Cy, Hyy Ne Os, nach Willstdtter u. Fischer?%: Os, Hyg Ny O,). E 
saurer Lisung zwei sehr charakteristische Absorptionsstreifen, 
nach Rot zu liegen, als die des O,-Hb; der zweite Streifen b 
einem helleren und einem dunkleren Abschnitt. Das Spektram 1 





Himoglobinderivate. Das Strema der roten Blutkirperchen. os 


ehen Senne yanphecinn ahnelt dem des neutralen Met-Hb resp. | 
(ren Hamatins in alkoholischer oder Stherisch ne aes (Fig. 16. 9a. ee 

‘vy | (vel. A. Schulz"). Das Spektram des H 

wer und alkalischer Lisung ist zum forensischen Nachweis des Bintes 


vissen Vergiftungen (z. B. Sulfonalvergiftung). * 
Durch Redektion des yring erbielten Nencki und stine Mitarbeiter 
1 villig sanersto@freien Kirper, das HAmopyrrol; diets ist ein methy ity gstral: 
i LR PS ee” 
] | a _— 
cH, —C On oder HQ. 0= 08, : 
x Nit 


Nach Fischer a. Hahn? exthilt dus Motekiil des Himins vier Pyrrolkerne. 
‘Aus dem Chlorophyll der grinen Biltier povaanen Schanck s. Marchleesis a 
thnliches Pigment, das phy Rednktion enteteht 

2 ane diesem Hitmopyrrol (Neaeki a Marehle gH), Daaach sind ithin das, Hames 
‘in und das Chlorophyll chemiseh verwandte Sabstanzen, Das Chlorophyll enthalt am 
lo dos Bisons des Himoglobins Magnesium (vgl. Willstatter «, ‘Stont) 

Durch (xydation des Hamatins erhiett Kaeter' zwei Siuren: Hamatinsaduren, 

Dor Blutfarbstoff ist chemisch aahe verwandt mit dem Gallen und Harn 
bstoff. Der Gallenfarbstoff Bilirubin C.,H,,N,0, ist isomer mit dem HAmatoporphyrin 
‘I,g8,0,; sowobl Bilirubin als Biliverdin' geben bei der Oxydation dicsolben Hlmntin= 
ton wie Hiimatin (Kitater™). — ma it anferhalb des Sarre stagniert und 
Zersetzung anheimfallt, x. B. in in geromencn Blut- 
pfea usw., a0 entsteht uns dem Himogtbia ein fnehsroter Farbstoff, das Hiimatoidin 
iyyN,O,. Es ist cisenfrei, krystallisiert in klinorhombischen Prismen, ist Walich im 
tnd warmen Alkalion. Wahrscheinlich ist ev identisch mit dem Gallenfarb- 
bin. Nach umfangreleher Anflisung von Blut in den GotsBen (x. B. mach 
isfusion fremdartigen Blutes) sah man Hisontoidinkrystallo im Urin, Avch im Harn bei 
ras und im Spotum sind Himatoidinkrystalle gefunden worden. 

Urobilin, einer der Farbstotte des Harns, li6t sich durch Reduktion des Himating 
tkaligeher Losung mit Zinn and Salzsiinre (Neneki u. Sieber’) oder durch Bi 
1,0, anf sanres Himatin (Moe Munn") gewinnen; Himopyrrol geht an der Luft 
selbst in Urobilin fiber; subcutane Injektion von Himopyrrol beim Kaninchen bewirkt 
scheidang von Urobilin (Neneki v. Zaleski"), — Urobilin findet sich mitonter in 
tan, Ex- und Transsudaten, — ebenso bildet es sich in steril bei Korpertemperatur 
townhrtem Blute (Ajetlo *""), 

Dos Chorioidealpigment und das Haarpigment stammt nicht ans dem Blat 
stotte (I. Spiegler ®), 











3. Das Stroma der roten Blutkérperchen und die weifen . 
Blutkérperchen. 


A. Das Stroma der roten Blutkiérperchen enthilt: ] 
I, Biweibkirper. — Nach Paseucci**' bestehen die trockenen Stro- 
ta rund zu */, aus Eiweifstoffen, Der hauptsiichlichste Eiweibstoff ist 
th Hallibwton*** ein Nucleoproteid. 
In don Kernen der kernhaltigen roten Blutkirperchen der Vogel findet sich Nuelein, 
(mmengosotat aus Nucleinsiiure und Histon (Ackermann), 
Il. Fette. — Neutralfett kommt in den roten Bint nicht 
3 dagegen Cholesterin (nach Manasse'**, Hepner '*°, Wacker u. Hueck¢ 
im freien Zustande, nach Cytronberg?*? dagegen bis zur Halfte und 
‘ther als Cholesterinester) und Leeithin (vgl. Beumer u, Birger #5). 
ch Paseucei*®* betragen die in Ather, Chloroform und Alkohol lislichen 
ffe rand */, der Trockensubstanz. 





[£23.] Dag Stroma der roten Blutkirperchon. Cthemie dor weiben Blutkirpert 


IL Kohlehydrate. — pia te ioe revert | 
daé Traubenzucker sich nicht in den rofen Blutkbrperchen, so: 
pp yas Gly! ae “ and a 

ttkens u. Sandgren'**, Bang enthalten die roten Blutkérper 
reducierende Substanz, die aber kein ‘lraubenzucker ist, nach 
Michaelis™, Rona a. Takahashi**, Lépine u, Boulud **, ” Frani 
schneider’ dagegen kommt Traubenzucker in den roten Blutk 
vor. In der Norm soll nach Hollinger™** der Zuckergehalt dei 
und der peloraiea Bestandteile gleich sein, nach Michaelis v 
kGnnen jedoch auch erhebliche Differenzen vorkommen. Masing 
da6 die Blutkérperchen verschiedener Arten verschiedene Ee 
fiir Traubenzucker besitzen: die Blutkiérperchen von Gans, K 
Schwein, Hammel erwiesen sich als nicht durchetngig, fur Tran 
und enthielten demzufolge auch im nativen Zustande keine irge 
heblichen Zuckermengen. Die roten Blutkérperchen yon Rind 1 
waren im geringen Grade, die des Menschen in viel hiherem 
‘Traubenzucker permeabel (vgl. Kozawa1). 


IV. Andere organische Bestandteile. — Harnstoff, gh 
anf Erythroeyten und Serum verteilt (Schindorg’™), Milchsiiure (Ir 


V. Wasser ca. 609. 
VI. Anorganische Stoffe, namentlich Kaliumverbindun; 


Die in der Asche gefundene Phosphorsiure und Schwefelsiure ist in den 
chon zum gréften ‘Toil nicht priformiert enthalten; die Phosphorsiiure stam 
Verbronnung des Lecithins, die Schwefelsiinre ang der Verbrennung der Kiwel 
Bintanalyse wgl pag. 84. 

B. Die weiben Blutkérperchen. Leukocyten ans L; 
(sowie Eiterzellen) enthalten von Eiweifkirpern Globuli fee 
Nucleoproteid (Halliburton, Mancini '**); ferner in den Kee 
histon, welches in Histon und ein Paranuclein, das Leuko 
zerfallt (Lilienfeld ‘**),— Von Fetten und fettihnlichen Stoff 
sich: Lecithin und Cholesterin (viel reichlicher als in den 
kbrperchen, Wacker u. Hueck***), Cerebrin, Protagon (Kossel 
cini™), — Yon Kohlehydraten ist Glykogen nachgewiesen (Sa 





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ae 



























































































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34, 1901, 1687. — 116, A. Willstatter u. A. Stoll: Untersachn fiber 
den und Ergebnisse. Berlin 1918. — 117. M. Neneki n. N. 
9. A.P.P. 24, 1888, 490. — 118, €, A Mac Munn: 
119. Ajello: Ref. in 0, i. M, 15, 1904, 502. — 120, E. Spice 
2B. — 121. O. Pasenced: WH. B. 6, 1905, 543. — 1: 5 
1895, 306. — 123. D, dekermann: Z. ph. Ch. 43, 1904, 299. = 124. P. Manasse 
14, 1890, 497. — 125. E. Hepner: P. A. 73, 1898, 585. — 126. L. Wacker n. 
ALP. P, 74, 1913, 416. — 127. S. Cytronberg: B. Z. 45, 1912, 281, — 128. 
a. M. Barger: A. P. P71, 1913, 311. — 129. H, Dyttkens a. JSandgren: B. 2 
982. 31, 1911, 153. 86, 1911, 261. — 190. J. Bang: B.Z. 38, 1912, 166. — 13 
u. L. Michaelis: .% 16, 1909, 60. — 132. PB. Kona a. D. Takahashi: B. %. 30, 
— 138. B. Lépine n. Boulud: B.% 32, 1911, 287. — 1M. E. Franku. A, Bre 
% ph. Ch. 76, 1911, 226, — 136, A. Hollinger; BZ, 17, 1909, 1. — 136. L 
 P. Rona: Bot, 18, 1909, 875 0, 514, 37, He 47. — 137. E. Masing: P.A. 
— 138, 8. Kozawa; (, P, 27, 1913, 793. B. 
PA. 63, 1896, 192. — 140, T, Jrisawa: Z, 
BZ, 26, 1910, 140. — 142. L. Lilienfeld: le 
D. m. W. 20, 1894, 146 a. 310. — 144. Salomon: D, m. We 1877, Nr. 8 0. 35, 
























24. Das Blutplasma und der Faserstoff (das Fibr 


Die unveriinderte Fltissigkeit des Blutes heift ,Plasma‘. 
scheidet sich jedoch meist schon bald nach dem Austritt des B 
den GeftiGen eine faserige Substanz ab, der ,Faserstoff*. Na 
Ausscheidung heift die nun tbrig gebliebene, spontan nicht mehr ge 
Fitissigkeit ,Serum*. Das Plasma ist beim Mensehen und 
Tieren gelblich, beim Pferde zitronengelb, bei anderen Tieren, 2 
Kaninchen, fast farblos. 

Darstellung des Plasmas. Um das Plasma darzustelle 
ndtig, die Gerinnung zu verhilten; dies gelingt entweder durch Ab] 
oder durch Zusatz gewisser Salze. 

A. Kiilteplasma. — Man lift das aus der Ader stréme 
(namentlich des Pferdes, welehes sich wegen der langsamen Gerinr 
schnellen Senkung der Blutktrperchen hierza besonders Le 
engen, in Kiiltemischung stehenden MeGeylinder flieBen. ler 
bleibenden Blute senken sich innerhalb einiger Stunden ey Eryt 
und das Plasma bildet oben eine, mit der (abgektthlten) Pipette al 
klare Fltissigkeit. Wird diese schlieflich noch (auf eiskaltem 
filtriert, so ist das Plasma auch von den Leukocyten befreit. E 
gerinnt das Plasma und geht dabei in eine zitternde Gallerte tiber 
man es mit einem Stabe, so erhiilt man den Faserstoff als fav 
Masse isoliert. 

B. Salzplasma, — Wird das aus der Ader striimende 
Mebeylinder unter Umriihren mit 1/; Vol. konzentrierter Lésung 
triumsulfat oder mit 25°,iger Magnesiumsulfat-Lisung (1 
auf 4 Volumina Blut) vermischt, so senken sich (am ktihlen ( 
Zellen, wihrend das klar obenstehende ;Salzplasma* abpipettier 
kann. Wird dem Salzplasma der Salzgehalt durch Dialyse entz 
tritt Gerinnung ein; dasselbe bewirkt schon eine Verdiinnung mil 
— Verhindert man die Gerinnung durch Zusatz von oxalsauren Sa 
Fluoriden (vgl. $25, Il. c), so erhilt man Oxalat-, resp. Fluorid 

bor das quantitative Verhiltals von Bintkérperchen und Plasma, dem Vo 
dom Gowieht nach ‘vl. pag. 37 0. 84. 

Der Faserstoff ist diejenige Substanz, welche sowohl in | 
leerten Blute als auch in dem Plasma (ebenso in der Lymph« 
Chylus) durch ihre Ausscheidung ans der Fitissigkeit die G 


| 
| 





Lait man ane der Ader Bist ruhiz | 
ee ee ee eet ee, nil isch zarten 
vppeltbrechenden Faden, welche die Blutkirperchen wie im eimem 
tsammenhalten und mit ihnen eine gallertiz feste Masse a 
an ,Blutkachen* (Placenta sanguinis) 
och sehr weich, 12 bis 15 Standen 


klare Filissigkeit , das Blutserum (Serom san: 
Rest des as (( minus Fibrin = Serum). Der Biutkuche 


Diew 
tavchentiate kommt es mamentiich vor, wenn Eoteindeagen im Korper herreche 
feusta phlogistics® (Speckbant) Die Cresta ander 
tridilinieses, und xwar int die Ureache der Bildung 


Wird frisch entleertes Blut mit einem Stabe geschlagen, + 
ickeln sich die auftretenden Faserstoffiden um den Stab heram, ma 
‘hilt so das Fibrin als faserige, grau-gelblich-weibe Masse. Das bri 
leibende Blut kann nun nicht mehr gerinnen: defibriniertes Blut; ( 
wsteht aus Serum und Blutkérperchen, 

Obschon das Fibrin voluminés erscheint, so betrigt es doch m 
(1—0,3%, der Blatmasse, merkwiirdigerweise kann in zwei versehiedene 
roben desselben Blutes seine Menge erheblich schwanken. — Der Fase 
off ist unlislich in Wasser oder Ather; Alkohol schrumpft iha dure 
ntwitéecrung, Salzsiiure ld6t ihn glasig aufquellen (unter Veriinderan 
t Acidalbumin), Er ist frisch zh elastisch; getrocknet wird er hornartij 
irchscheinend, spriide and pulyerisierbar. 

Veisohow Pibrin vermag 1,0, lebbaft in H,0 und O xu zerlegen. Gekoeht od 
iter Alkohol anfhowahrt, yerliert ow dieses Vermégen. 

Frigoh list Fibrin sich wnf in G—8%,igen Losungen von Natriumnitrat od 
tirlumvulfnt, In dinnen Alkalien und Ammoniak; Hitze konguliert dios» Lésungen nick 
ich schwache Ldwungen yon Hnloidsalxen (NaCl—NH, Ol—KJ—NaJ—Na FI—NH, B 
ton bol 40" daa Fibrin, x, Hh. Kochealzkisung von 0,7 —2,0%. Auch Serum Wet zreweily 
@ gobildote Fibrin wieder auf: Fibrinolyse; am stirksten bei Phi 
hruchaintich handelt o« gich dabei um die Wirkung eines fibrinolytischen Fermentes, 





25. Allgemeine Erscheinungen bei der Gerinnung.* 


I, In unmittelbarer Bertihrung mit der lebendigen und ur 
erinderten Geflibwand gerinnt das Blut nicht (Hewson, 177% 
haekrah, 1819). Daher konnte Britcke® auf 0° abgekiihltes Blut in noe 
hlagonden Herzen getiteter Schildkréten & Tage ungeronnen erhalter 
tagniert das Blut in cinom lebenden Gefiibe, so tritt in der zentrale 
chse Gerinnung cin, weil hier kein Kontakt mit der lebenden Geftif 
and besteht, L&bt man Blut so aus einem GefiS austreten, dab es nu 
it unyerletater Intima in Bertlhrang kommt, nicht mit der Sehnittflach 
adem man die Intima aus dem Lumen des durchschnittenen Gefai®e 
srauszieht und nach anfen umklappt), so gerinnt das Blut 6—Tma 
niter als das Blut aus einfach durchschnittenen Gefiiben (Unger 3). — 
merhalh toter Herzen oder Gefiibe, oder innerhalb anderer Kaniile, z. B 


[$25] Aligenteme Krscheinungen bei der Gerinnung, 


der Harnleiter, gerinnt das Blut schnell. Daher kommt es auch 
Blatung infolge yon Verletzungen durch die Berlihrung des Bi 
den verletzten und somit an dieser Stelle absterbenden Gew 
Wunde und der GefiGwand im allgemeinen schnell zur Ausbildi 
verstopfenden Blntpfropfes durch Gerinnung und so zur Still: 
Blutung. 

Ist die Gefidwand durch pathologische Prozosse reriindert, so kant 
bostehendem Kreislauf an diesen Stellen Gerinnung eintreten. 

Bei Bertihrung mit fremdartigen Koérpern kommt es 
zor Gerinnung des Blutes, wenn das Blut an denselben adhiriert (/ 
z. B. die Wiinde des Gefiifes, in dem das Blut bei der Entleer 
gefangen wird: der Stab, mit dem es geschlagen wird; Faden unc 
welche in die Ader gebracht sind; auch Bertthrung mit der Inti 
fremden Art bewirkt sofortige Gerinnung (Unger*), Dagegen ge 
Blut nicht bei Bertihrung mit solchen fremdartigen Kérpern, ; 
es nicht adhiriert (z.B. an eingefetteten) (Freund®). Wiingt 1 
in einem mit Ol oder Vaseline eingefetteten Gefiibe auf, so bleibt « 
selbst wenn es mit einem ebenfalls eingefetteten Glasstabe gi 
wird; es gerinnt aber sofort, wenn es mit einem nicht eingefettete 
stande in Berlhrung gebracht wird. 


Il. Verhindert oder verzigert wird die Gerinnung des 

a) durch Kiilte. Wenn man Blut sofort gefrieren luibt, so is 
dem Auftauen noch fllissig und gerinnt erst dann. 

b) Durch hohen CO,-Gehalt; daher gerinnt das Venenblat ki 
als das arterielle; bei Erstiekten bleibt das Blut lange fitissig. 

ce) Durch Ausfiillen des Kalkes (Arthus u. Pagis) 
oxalsaurer Salze (1g auf 1 Liter Blut) oder Fluornatrium 
auf 1 Liter Blut) oder zitronensaurer Salze (O04—0.6%, zitror 
Natrinm in 0,9°/o NaCl-Lisung, mit gleichem Volumen Blut gemis 
Seifen (in stiirkerer Konzentration). Fiigt man zu dem so ¢ 
Plasma wieder Kalksalze hinzu, so tritt Gerinnung ein. 

a) Darch Vermischung mit Salzljsungen: Chloralkalien, 
Phosphate (3°/,iges Dinatriamphosphat), Nitrate, Carbonate, lis! 
cium-, Strontium-, Baryumsalze zu 0,5°/, im Blut geltist. Am gil 
gerinnungshemmend wirkt Magnesiumsulfat (1 Vol. gesittigte 
a 3 Vol. Blut). 

Rbenfalls gorinnangshemmond wirkt: Zesats von Eiereiweif, Zack 
Glycerin oder viel Wassor, Zosate von Alkalien oder von Ammoniak se 
ringeren Mengen, — abor auch Ansiinern mit schwachen Sauron: Essigais 

e) Nach Injektion yon Pepton ins Blut (0,59 anf 1kg Ho 
auf Lkg Kaninchen) wird das Blot gerinnungsunfihig (Sehmidt-M 

Nach Pek u. Spiro’ kommt die gerinnnngshemmende Wirkang jedoch 
Popton als solehom 2n, sondern einer Beimengung, dem .Peptoxym*. Ebens 
jektion yon tryptischem Pankronsferment (Albertoni®), diastatiachem 
(Salcioli, Serum des Aalbintos (Mosso') gerinnnngshemmend. — Bei der 
Autolyse von Organen entstehon gerinnungshemmende Lisungen (Conradi™ 

f) Das Mundsekret des Blutegels wirkt gerinnungsh 
daher kommt es, dab die yom Blutegel gebissenen: Wunden lang 
Der wirksame Kérper, das Hirudin, ist von Franz ** (unte 
Leitung) rein dargestellt worden. Abnliche Substanzen kommer 
Zecke (Ixodes ricinus) (Sabbatani*®) and dem Anchylostomum ¢ 


; ‘Weatn dee. Gerinnung. 3: 


Loeb u. Smith**) yor. Das Gift der Sener aed zB. Kobragi 
Vorawitz"®), wirkt gleichfalls gerinnungshemmend, 

&) Das Blot der peRahemvrs dss gerinnt vor dem 12,—14. Tage bees ns st 
ts Blut der Nieronvene — das der Lebervonen sehr wenig, — Bint (Hund), welehes 
trch das Herz und die Lungen geleitet wird, gerinnt lange Zeit hindurch nicht (ire! 

* Blut, welchom die Cirenlation durch Leber und Darm verschlossen ist, gerinnt gar mi 

iohr*), — Fotalblnt im Momente der Geburt gerinnt frith, uber langsam, sein Fibrin 
Ut ist nt gsring (Kerlger — Das Menstraalblut zeigt geringere Neigung zur 
Us dem: reichlicher alkalischer Schleim ans den Geschlechtsteilen 

h) Bel der ,Blntorkrankheit* (Hamophilie) ist eine stark verminderte 
Jit des Blntoe vorhanden, 80 dafl selbst kleine Wanden sehr linge bloten. Die Ursache 
is Fehlen der Thrombokinaso (8, anten), das Protoplasma der geformten 
18 Bintes, vielloicht sorar allor Zollon dos Karpers hat das Vermigva eingebit, Throml 
nage au liefern (Swhli'*, Morawit: u. Loxsen™), 

Auch bei Cholamie kommen bisweilon sehwor stillbare Blatungen zur Reobachtur 
wren Entstehen noch nicht anfgeklirt ist (vgl. Moravit= u. Bierich™). 

Ill. Beschlennigt wird die Gerinnung: 

a) Durch Erwirmung (yon 49—55°; vgl. IV). 

b) Durch zahlreiche Stoffwechselprodukte: Harnsiiure, Glyci 
aurin, Leucin, Tyrosin, Guanin, Xanthin, Hypoxanthin (nicht Harnstof 
te Gallensiiuren, Lecithin, salzsaures Cholin, Protagon. — Intravent 
ajektionen von Gelatine sollen bewirken, dab das Blut nach dem Austri 
us den GefiiBen fast momentan gerinnt (Dastre u. Floresco**); yon andert 
‘ird diese Angabe bestritten oder auf den Kalkgehalt der Gelatine zurtiel 
efhrt (Camus u. Gley*, Sackur **, Zibell *), 


IV. Auf die Blutgerinnungszeit hat nach den Untersuchange 
on Biirker®* die Temperatur einen grofen, aber durchaus regelmiBigy 
influb. Birker** fand die Blutgerinnungszeit bei 1) au 18.5 Minute 
‘17,99 zu 10, bei 24,2° zu 6,5, bei 28° zu 4, bei 34,7° zu 3.5, b 
9,8° zu 2,75 Minuten. In den ersten Nachmittagsstunden scheint ein M 
imum der Gerinnungszeit vorhanden zu sein. Fir verschiedene Individug 
t bei gleicher Temperatur und gleicher Tageszeit die Gerinnungszeit ei 
emlich konstante Grifie (Biirker**). Nach starken Blutverlusten wird d 
erinnungszeit abgektrzt, bei schneller Verblatung gerinnen die letzte 
lutmengen am schnellsten (Arloing*?, Arthus**, Milian®). Nach v¢ 
er Velden® erkliirt sich die Erscheinung dadurch, dab nach Blutverlust« 
ewebstltissigkeit in die Gefiife eintritt und reichlich Thrombokinase m 
ineinschwemmt. 

Finen Apparat zor Bestimmung der Bintgerinnungszeit bei konstantor, jeweils | 
immter Temperatur hat Barker“! angegeben. 








26. Wesen der Gerinnung. 


Alexander Schmidt® hat (1861) ermittelt, dai die Gerinnung ej 
srmentativer Vorgang ist: durch Kinwirkung eines Ferments, we 
hes -Fibrinferment® “oder ~Thrombin* (Thrombase) genannt wir 
ird ein lislicher Eiweibkirper des Plasmas, das Fibrinogen, in ein 
nlislichen Kérper: das Fibrin, umgewandelt, 

A, Schmidt®* nohm urspriinglich un, daB anBor dom Fibrinogen oder der tibrinogen 
thstanz noch ¢in anderer Korper: die fibrinoplastische Substunz (Serumglotnll 
ql. pag. 80) bei der Gerinnnng beteiligt sci; beide Korper falte er zusammen unter @ 
seeichnung: Fibringeneratoren. Hammarsten™ (1875) wies uber nach, daB das Fibs 
th nur ans dem Fibrinogen unter der Einwirkung des Fibrinferments bildet 

Man hat angenommen, da durch das Thrombin eine Spaltung des Fibrinogens ant 
asseranfoahme stattindet in das Fibrin und eine geringere Menge ciner flissigbleibend 








[$26) Fibrinogen. Pibrinferment, 


Globelinsubstanz: das Fibringlobutin (Hammarsten™, Heubner*); yon anderer 
diese Anschanung bestritten (uiskunp® % 

Das Fibrinogen — ist ein Globulin a (vel. (val. pag. aed Es ist 
verdtinnten Alkalien lislich und wird aus di sung beim Du 
von CO, niedergeschlagen. Es ist ferner Wislieh in in verdiinnten "Sal 
z.B. in dinner (5—10°/,) Kochsalzlisung; durch Halbsiittigung m 
salz, wird es zum gribten Teil gefuillt, yollstiindiy bei Ganzstittigung 1 
salz. Seine Lisung in Kochsalz koaguliert beim Erwiirmen auf | 
Die Zusammensctzung ist nach Hammarsten® C5298 16,9 N16, 
0 22,26/,, die spezifische Drehung  [D]=—52,5° (Mittelbach **) 

Darstellung des Fibrinogens. Fibrinogen kommt auber in 
noch in den sogenannten lymphatischen Transsudaten (z, B Hy 
fitissigkeit, ein Transsudat in der serdsen Umbtillang des Hodens) 
wird daraus (Salzplasma, Transsudate) durch Vermischen mit dem 
Volumen gesiittigter Kochsalzlisung ausgefillt, und durch wiederho 
lésen in dtinner Kochsalzlisnng und Ausfillen mit gesiittigter K 
lésung gereinigt. 

Entstehung des Fibrinogens, Das Fibrinogen ist bereits im Plasma 
lierenden Blates vorhanden; seine Menge nimmt (im Gegensatz 2n ilteren Vor 
walche das Fibrinogen sus einem Zerfull der zelligen Elemente im entlearten 
stehon NaBen) nach der Entloerung nicht xo. Wohor dag Fibrinogen des Blutplasm: 
ist nicht mit Sicherheit bekannt, vielleicht ans der Leber (Whipple*, Goodpast 
dem lymphoiden Gewebe. Nach P. Th. Maller’ ist dus Knochonmark elao Urap 
des Fibrinogens; die Fibrinogen bildendo Titigkeit desselben wird darch die F 
bakterieller Produkte betriichtlich gosteigert. (Vgl. Morawits u. Kehn*®.) 

Das Fibrinferment (Thrombin, Thrombase). Dars) 
Nachdem die Gerinnung zum AbschlnG gekommen ist, bleibt das 
welches ja entsprechend seiner fermentativen Wirkung bei dem ‘ 
nicht verbraucht wird, im Serum zurtick, es kann aus diesem in | 
Weise hergestellt werden. Blutserum wird mit dem 20fachen 
starken Alkohols vermischt, der Nicderschlay, welcher aus Eiweib 
ment besteht, 2—4 Wochen unter dem Alkohol stehen gelassen. 
wird das Riweif koaguliert, in Wasser unlislich. Man filtriert nac 
Zeit, trocknet den Niederschlag tiber Schwefelsture und extrahiert 
Wasser: das Ferment geht in Lisung, das koagulierte Eiweib bleib 

Werden die Lisungen des Fibrinogens und des Fibrinferm 
sammengemiseht, so entsteht sofort Vibrinbildung. Am giinstigster 
bei die Kirpertemperatur: O° verhindert die Gerinnung, di 
hitze zerstirt das Ferment. Die Menge des Fermentes ist glei 
gréBere Mengen bedingen schnellere, aber nicht yermehrte Fibrir 
dung. Zor Fibrinbildang ist ein gewisser * Salzgehalt der Fliissi, 
forderlich (1°, Kochsalz), sonst tritt sie nur Jangsam und teilw 

Buistekene des Fibrinfermentes Im Plasma des circu 
Blues ist noch kein Fibrinferment vorhanden (oder nur ger) 
Auslisung der Gerinnung nicht ausreichen'!e Mengen; auch sind in 
gerinnungshemmende Stoffe vorhanden, welche die Wirkung des ¢ 
handenen Fermentes aufheben). Dagegen enthilt das Plasma des 
renden Blutes eine unwirksame Vorstafe des Vibrinfermen 
Prothrombin oder Thrombogen, 


Vel. ber analoge Profermente: Propapsin (§ 110), Trypsinogen (§ 114 


Das wirksame Thrombin wird aus der unwirksamen Vorst 
Thrombogen, gebildet durch dio Thrombokinase (Aktivier 


‘8 Wesen der Gerinmung. ¥y 

. fy 
Phrombogens), Diese ist ein ganz allgemeines Protoplasmaprodukt, 
indet sich in den Gewebssiiften, aber auch in den zelligen Elementen ¢ 
Blutes, speziell den Blutplattchen und Leukocyten, welche die Thromt 
sinase an die Blutfltissigkeit abgeben, wenn sie durch die Bertihrang m 
sinem Fremdkérper dazu gereizt werden. Bei den Siiugetieren sind wal 
icheinlich die Blutplittchen die Hauptquelle der Thrombokinase. Z 
Sinwirkung der Thrombokinase auf das ‘Throm! ist aber endlich no 
jie Anwesenheit von Kalksalzen erforderlich, ohne da® man zarzi 
ron der Rolle, welche die Kalksalze bei der Umwandlung des Thro 
oogens in Thrombin durch die Thrombokinase spielen, eine klare V¢ 
itellung geben kénnte. Jedenfalls ist die Anwesenheit der Kalksalze n 
srforderlich fiir die Bildung des Thrombins; ist einmal wirksam 
Chrombin entstanden, so erfolgt die Binwirkung desselben auf Fibi 
togen auch ohne Gegenwart von Kalksalzen (Fuld u. Spiro, Mor 
vite 42), 

Direkt ang der Ader in Fluornatrinmlisung flieBendes Blut liefert kein Ferment 1 
No Fermentbildung bereits begonnen, so kann sie durch Zasatz von Finornatriam sof 
ehemmt and der Fermentgebalt des Biutes anf seinem in diesem Augenblick orreich! 
Vert erhalten werden (Arthus™). Aug frisch hergestelltom Oxalatplasma kinnen durch 1 
ration durch Berkefeldflter dio Blatplittchen villig ontfernt werden; bei nachtrliglich 
Susntz von Kalksalzen tritt dann keine Gerinnung oin, weil keine Blutplittchen, also at 
teine Thrombokinuse vorhanden ist (Cramer u. Pringle"). 

Rei der Bildung des Thrombins aus dem Thrombogen wird niemals alles vorhandi 
Thrombogen verbraucht, es findet sich daher im Serum immer noch 'Thrombogen, welcl 
lurch Zasatz von Gewebssiiften z. B. aktiviert werden kann. Andrerssits geht das Throml 
tebr schnell nach der Gerinnung wiederam in eine unwirksame Form fiber, das Me 
brombin; ana diosem kann durch Alkalien oder Siinren wieder Thrombin gebildet wors 
und zwar anch bei Abwesonheit von Kalksalzon). 

Dio Borihrung mit Fromdkérpern ist nicht nur fir die Abgabe der Thrombokin 
(ng den geformton Elomenten erforderlich, sondern auch fir die Kinwirkung von Thre 
togen, 'Thrombokinase und Kalksalzen anfoinander und somit fur die Bildung des Thrombi 

Die Gerinnung vollzieht sich demnach in zwei Stadien: 1. Bildu 
les Thrombins aus dem Thrombogen durch die Thrombokinase bei Gege 
wart von Kalksalzen. 2. Bildung des Fibrins aus dem Fibrinogen dur 
Jas Thrombin, Das folgende Schema gibt (in Anlehnung an Fiule*>) ¢ 
Bild des Gerinnungsvorganges: 


Blut 
Plasma geformte Elemente 
(Blutpliittehen, Leukoeyten) 
Fremdki 
<— ‘Adhiisio 
Thrombogen Kalksalze = Thrombokinase 
+ 
rinogen. Thrombin 


Fibrin 


Bei dor komplizierten Natur des Gorinnungsvorgangos kann or in sehr versehied 
tiger Weise bocinfiuSt worden, jo nach dem Stadium, in welchom das betreffende Mom 
virkt. So kann 2. B. die Gorinnung ansbleiben aus folgenden Grandon: 

1. Fohlon dos Fibrinogens. Seram oder doflbriniertes Blut geriant nicht, w 
w kein Fibrinogen enthiilt. — Wird cinom Hunde vin gewisses Quantum Blut enteog 
lofibriniert und wieder eingespritzt und dieses mahrfxch wiederholt, so enthilt schlieBlich « 


(#27) Chemsche #°""Mensetzung des Blutplaxmas wnd dex Serums. 


Bt in a TE ee ee Nach 24—48 Stunden hat sich 
wieder rogenerlert 


(Dastre *), 
Bol der sa ibe belle) nimmt He Menge des Fibrinogens im 3 
mehr ab, kurz yor dem Todo fehlt das Fibrinogen ganz; dag Blut ist alsdann 0 


- ae Zeit ist aber auch a Thrombogen im Tato vormindert (Corin a. 
facoby *), 

Dio Ungerinnbarkeit des Leichenbintes beruht fast immer anf dom 
Fibrinogens infolge von Fibrinolyse; meist enthiilt das Leichenblnt aber auch Fi 
nor in geringer Menge Firion hal 


2 Feblon dos Thrombogens; #, B. bel Phosphorvergifinng (* unter 
3. Fehlon dor Kalksalze; 2. B. im Oxalat-, Flnoridplasma, 


4. Fehlen der Thrombokinase. Bei Mangol der Adhiision geben dir 
Elemente des Blutes keine Thrombokinase ab, so 2. B. beim Auffangon des Bl 
gofotteten GefiBen; ebenso im intaktan Kérper. — Vogelblut (von Giinsen 
gerinnt nar dann schnell, wenn es mit verletzton Geweben in Berihrang ko: 
Neforn dann die Thrombokinase. Fiingt man es so anf, daB es nicht mit Gow 
unreinigt wird, so bleibt ex im Gogentell sehr lange fliigsig; os enthalt ni 
Blatplittchan (welche beim Stingotiorblat schnell Thrombokinase liefern) und die 
scheinen nar schr langsam Thrombokinase abzngebon. — Ober das Fehlen do 
kinaso bei Himophilio « pag. 76. 


&. Wirkung gorinnungshindernder Agentien. Diese kénnen en 
Bildung des Thrombins aus dem Thrombogen verhindern, also der Thrombokinas 
wirken: Antikimasen, oder aber die Bildung des Fibring ans dem Fibrinogen 
also dem Thrombin entgegenwitken: Antithrombine. Die Verbinderung der 
durch Abktihlung barnht ant redgerung der Fermantbildang, ebenso der 
hommende Einflu der Noutralsatze; in stirkeror Konzentration verbindorn 
dings anch die Wirkung des fertigon Fibrinfermentes (Bordet n. Gengou). D 
des Kobragiftes beruht anf einer Antikinase (Morawits"); die dos Hirudi 
anf einem Antithrombin (Morawits®, Fuld u. Spiro"; vgl. aber Schit 
Bodong *), — Boi anderon gerinnnngshemmendan Agentian worden dia sigentlich 
Antikirper erst im Organismus gebildet; so bel der Gerinnungshammung dare 
yon Pepton, Aatblat. Der wirksame Antikorper entsteht daboi in der Leber; 
schaltang der Leber (Hédon u. Delezenne™, Gley a. Plachon**) bleibt die Wi 
Vielleicht oatstobon auch unter normalon Vorhiltnisson im Organismus rogeln 
Antikirper, die bei dem Fifissighleiben des Biutes in dem intakten Korper mit 
splelon mdgen- 














Pathologisehes. Kine Vormohrung des ans dem Blato bei der Gerinna 
scbeidonden Fibrins anf 1,0"), und mehr (normal 0,1 —0,8%,, vgl. pug. 74) wird 1 
inose bescichnet; sic kommt bei gowissen fieberhafton Krankheiten yor: 
Plouritis, Gelonkrhenmatismus. Boi Abdominaltyphas fehlt sic, Ein Sinken dor 
unter 0,1°/,, Hypinoso, kommt bei schworen, langdanernden Typhon, Kiterungen, A 





27. Chemische Zusammensetzung des Blutplasm 
und des Serums. 


I. Die Eiweibkérper® — betragen im Plasma 7—8%/,. 1 
ma unterscheidet sich vom Serum durch seinen Gehalt an Fibs 
die Menge desselben ist aber nur gering (§ 24). Ist bei der € 
das Fibrinogen als Fibrin ansgeschicden, so ist damit das P| 
Serum geworden. 

Die Eiweifkirper des Serums kinnen zuniichst in zwei 
getrennt werden: die Globulin- und die Albuminfraktion. Dur 
gung mit Magnesiumsulfat (Hammarsten'*) oder durch halbe { 
mit Ammoniumsulfat (Kauder®?) oder Zinksulfat wird die Globuli 








) Chemische Zusammensetcung des Bintplasmas and des Serums. 


negefillt; aus dem Filtrat erbiilt man darch i mit 
ilfat, Natriumsulfat oder Zinksulfat die Albuminfraktion. 


A. Die Globulinfraktion enthiilt: 













1, Das Serumglobulin (friiher auch fibrinoplastische Anz 
lobulin, Seramcasein genannt) wichtigsten Bestandteil. Es ist | 
 Lisungen yon Neutralsalzen (10*/, NaCl) und in Alkalien, C 
tinem Wasser. Aus seinen Lisungen wird es daher ausgeftillt bei 
nung der Salze dureh die Dialyse oder durch starke Verdin: 
fasser, sowie durch schwaches Ansiinern mit Essigsiiure oder 1 
on Kohlensiure. Es koaguliert bei 69—75°; spez. Drehung = —47, 
rédéricg®*), 7 

Waheschelolich ist das Seramglobnlin kein einheitlicher Kérper. Man kann nach. 
Salichkeit und Fillbarkeit wenigstens zwei Korper darin unteracheiden: das leicht iltha 
uglobalin (bei cinem Gebalt von 28 36 Volumenprozent Any 
tsfallond) und das schver filllbare Pseadeglobulin (bel 36—44 Volumenproxent 4 
ittigter Ammonsulfatloaung ausfallend, Fuld w. Spiro™, Pick). Doch ist die Abgrenxa 
vischen beiden Fraktionen keine scharfe (Pick *), weitergehende 'Trennung d 
srschiedenen Globuline haben Freund u. Joachim®' sowie Porges u. Spiro” wusgefth 

2. Das Fibringlobulin kommt regelmifig in geronnenen Fibrinoge 
isungen nach stattgefandener Fibrinbildang vor, daher auch im Serar 
8 entsteht bei der Fibrinbildung, doch ist nicht niiher eres. welch 
feise (vgl. pag. 77). Es ist wie das Fibrinogen fallbar durch Siittigur 
‘it NaCl oder durch 2s°/,ige Suittigung mit Ammoniumsulfat. Es koagulie 
4 64—66°. 

8. Fin Nucleoproteid, nach Pekelharing™ wahracheintich identiseh mit dt 
brinfermant. Nor in sehr geringon Mengeo im Serum vorhanden (im Pferdebiuteert 
O15 0,02"), Ieiebermeister *), 


4, Gintotin (Faust), dessen Natur noch zwoifolhaft ist. 











B. Die Albaminfraktion enthilt als einzigen Bestandteil: 


Das Serumallumin. Es ist auch in villig salzfreiem Wasser lislie 
ird nicht gefiillt durch Magnesiumsulfat, dagegen gefillt durch Siittigur 
iit Ammoniumsulfat (s. 0.). Es koagaliert in destilliertem Wasser sehc 
ai etwa 50°, in salzhaltigen Lisungen aber erst bei bedeutend héher 
emperatur. Spez. Drehun, —61". Es krystallisiert in hexagonale 
rismen mit einseitig aufsitzender Pyramide; die Krystalle sind doppe 
rechend, koagulieren durch Hitze (Giirber®, Michel”). 


Viclleioht ist auch das Seramalbumin kein elnbeitlicher Kérper. Halliburton ®* ante 
haidet nach der Gerinnungstemperatar 2, &, y-Serumalbumin, and Kauder™ erhielt darn 
aktloniorte Pillang mit Ammoninomauifat Fraktionen mit weit auseinander Negenden G 
nnungstomperaturen. Roi der Krystallisation bleibt regelmiig oin alcht krystallisierend) 
nteil zurfick, der vielloicht ein anderer Kirper ist als das krystallisieronde Sernmalbumi 

Der Fiweifgebalt dos Plasmas stoigt fast in allen Fallon von Infoktion, Dy, 
ibrinogengehalt ist am stirketen vermebrt unter dem Kinflusse der Paeonmocokke: 
id Streptocokkeninfoktion (vgl. pug. 79). Dns Verhiiltnis yon Globulin zu Albami 
or tog. .Kiwoibquotiont*) ist bei cinzelnon Ticrarten verschioden, beim Pferd und Rix 
t die Menge des Globulins groBer als die des Albumins, bei anderen Blntarten, ebenso # 
(ute des Menschen Gberwiogt die Menge des Albumin fiber die des Globulins (Leminake™ 
a EiweiGqnotiont soll sich bei der Infektion xa Gunsten des Globalins jindern, doc 
ichen die Angaben vorschiedener Untorancher in dieser Bezichnng voneinander ab (Lamy 
ein a. Mayer, P.Th, Matlor®’), Kine Yermehrang des Globulin im Verhéltnis 2nj 
lbumin fand Erben™ bei parenchymatoser Nophritis, Im Hunger nimmt die Menge di 
labulins 20 (Lewineki®). Boim Wiedorersatz der BinteiwolBkirper nach starken Binten 











is 2) Chemische Z0*MMengetgune des Blutplasmas und des Serums. 


zicbungen fiberwiegt zunichst die Albuminfraktion, spiiter orst orfolgt die Vern 
Globoline (Morawits™, Inagaki"), 

Albumosen wurden im Blutseram yon Embden a. Knoop**, Langstein 
Lorchardt* gefunden; dies Angabe wird jedoch von Abderhalden ™ ani seinen 
bostritten, Nach Abderhalden enthilt in dor Norm das Blutplasma keine Sto: 
Biuretreaktion geben und nicht eiweiGartiger Natur sind. fand Abderha 
wihrend der Verdaunng Aminosinren im Blate in sehr geringer Menge an 
wahracheinlich ist aber anch im Hunger das Blot nicht frei yon Aminosiiuren, 


Zu den Eiweifkérpern gehiren wabrscheinlich, obwohl ihr 
schen Natur nach nicht genau bekannt, gewisse Stoffe, welche | 
kiérper oder Schutzstoffe des Blutes bezeichnet werden; si 
zam Teil schon normalerweise in geringer Menge im Blute entha 
in gréferer Menge treten sie jedoch erst auf, wenn dem Blute 
Kérper oder Substanzen, die sehiidliche Wirkungen auf de 
austiben kinnen, in das Blut gelangen. Die Antikirper h 
schidliche Wirkung der fremdartigen Substanzen mehr oder wei 
sie stellen eine Schutzeinrichtung des Kérpers dar. Stoffe, welche Ai 
bildung veranlassen, werden als Antigene bezeichnet; es koi 
verschiedenartige Kurper sein, geformte Elemente und geliste St 
Nach der Wirkung der Antikérper kann man unterscheiden; B 
lysine, Hiimolysine, Cytolysine; sie lésen Bakterien, Blutk: 
oder Zellen einer anderen Art auf (ygl. § 14). — Agglutir 
bringen Bakterien, aber auch rote Blutkérperchen, Leukocyten 
»Verklebung* (z. T. diagnostisch wichtig, Widalsche Typhusreal 
Antitoxine; sie entstehen unter der Einwirkung yon Toxine 
wechselprodukten von Bakterien, aber auch durch manche tierische u 
liche Gifte), sie machen den Kérper gegen ein bestimmtes Toxin ir 
Pricipitine; sie bilden sich im Blute von Tieren, welche mit 
kérperfremder Stoffe, z. B. Blut, Milch einer anderen Art vor 
sind; sie erregen in dem Stoff, mit welchem das Tier vorbehande 
Niederschliige. So liefert z. B. ein mit Menschenblut behandeltes B 
ein Serum, welches nur in Mensehenblut Niederschliige gibt; 
Rinderblut vorbehandeltes Kaninchen ein Serum, welches nur in f 
Niederschliige gibt, usw. Man kann auf diese Weise Menschen- 
blat unterscheiden und die Blutart diagnostizieren (forensisch 
(Uhlenhuth®). — Abwehrfermente (Abderhalden*); sie treten 
auf, wenn dem Blate fremde geliste Sabstanzen in das Blut 


In der Norm werden sowohl yom Verdauungskanal aus, als auch von der 
Orgune nur ganz bestimmte Sabstanaen in das Blot abgegeben, die ,blutel 
-plasmacigen* sind. Die Bestandteile der Nahrung stammen von andern Tie 
Aus dem Pflanzenreicho; sie sind ,artfromd*, .korperfromd*; durch den \ 
vorgang (Darmzollen, Laberzollen) werden sie erst ihrer fremden Arteigenttsnlich) 
(3.150. 3) und sodann als ,kirporcigenes*, .plasmacigones* Material den 
gefthrt, Bringt wan unter Umgebang des Vordanungskanals (paronte 
Injoktion unter die Hant oder in das Geflidsystem solche blutfromde Sabstan 
Korper, so troten im Bintplusma Permente auf, welche diese Substanzen 
vormigen: die feblende Verdanung erfolgt soxusagen parenteral. So tritt nac 
von Robrucker Invertin im Blate auf (Weinland®*, Abderhalden”*), nach In 
blatfromdem Kiwei8 (Eiereiweif, Blutsernm einer anderen Art, Seidenpepton, K 
proteolytische Fermonte, Aber auch ans den Organen des Kirpers kOnnen unter 
Verhilinissen blutfremde (wenn auch arteigens) Substanzen in das Bint be 
hier zum Auftreten proteolytigeher Fermante Veranlassung geben, Abderhalden 
im Blutsorum sufinnlicher oder nicht achwangerer weiblicher Individuen ni 
monte yorkommen, die Plicentagewebo abbanen; nach Kintritt einer Schwang, 








xogen onthalt dag Blut vom 8. Tago nach der Befruchtang an wikrend der ganz 
Schwangorsehaft derartige Fermente. Durch den Nachweis von Fermenten im 


Landol#-Roremann, Physiologie, 14. Aut. 


Chomische Zusammensetzang dex Blutplasroas und des Serums. [$27 


Placentagewebe abbanen, kann mit groBer Sicherheit die Diagnose der Soh 

tellt werden, Diese Fermonte verschwinden innerhalb 14—21 Tagen, wenn die 

it mebr mit dem miitterlichen Organismas in Verbindang steht. — Ganz 

der Befand Abderhaldens, dad das Seram von Carcinomkranken Carcinomgewebe abban 
or nicht Placentagewebe). 

Hedin® fand im Ochsenserum ein schwaches proteolytisches Bnxym (wielleich 
den Lenkocyten stammond, vgl. pag. 52). 

Il. Fette. — Neutrale Fette kommen in Form mikroskopise) 
‘inster, oft nur bei starker Vergréferung eben sichtbarer oder nur dure? 
3 Ultramikroskop nachweisbarer Teilchen vor (Leeuwenhoek, 1673; vel 
.7, IV). Die Menge wird sehr verschieden angegeben; Kngelhardt** fanc 

normalen menschlichen Blute 0,186%/, (Atherextrakt), Boénninger® 
gegen 0,75—0,85°/, (Alkoholextrakt). Vermehrt ist der Fettgehalt be) 
chlicher Fett- oder Milchnahrung bis zur milchigen Trithung des Serum; 
visser u. Brduning**, Lattes**; M. Bleibtreu®* fand bei gemiisteten Giinsen 
26°/, Fett im Blut), andrerseits aber auch im Hungerzustande om 
—100%, erhtht (Fr. N. Schulz*?). Auch bei Schwangeren und Wéech- 
‘innen ist der Fettgehalt des Blutes erhéht. (Ober Lipiimie ygl. pag. 87.)— 
ifen, — Lecithin, — Cholesterin, als Olsiiure-, Palmitinsiiure- und 
warinsiiure-Ester, 0,17°/. (Hiirthle**), auberdem aber auch frei (Hepner ®, 
tsche, Fraser u. Gardner™, Wacker u. Hueck®). Nach Réhmann® wi 
5 freie Cholesterin durch ein besonderes Ferment, die Cholesterase, aus 
1 Estern abgespalten. Audenrieth u. Munk ** fanden 0.14—0,16°/, Gesamt- 
olesterin in normalem Menschenblut. — Tangl u. Weiser wiesen freies 
yeerin im Plasma nach. 

Nuch Cohnetein u. Michaetis® hat das Blut die Kigenschaft, in ihim enthaltenes oder 
stich xngesatates Chylnsfett bei Gegenwart von Sanerstoff in einen wasserlislichen, 
yaablen Korper umgzuwandeln (,Lipolyse*), Nach Hanviot™ kommt im Blut ein Ferment 
(Lipase), welchos Nontralfett in Glycerin und Fottsiinro zerlegt, Bel Zanahme des Fett: 
altes dos Blutes (vermehrte Fettzufubr, Hungor) stoigt der Gehalt des Blntes an Lipase 
Abderhalden™), Auch Fermonte, dic Cholesterinfettsiturcester spalton, kommen im Blute 
(J. H. Schultz"), Welche Bedeutung diesen Formenton xukommt, ist noch nicht klar, 

Ill. Kohlehydrate. — Traubenzucker (J. Bang’) ist stets in 
‘ingen Mengen im Blute vorhanden (Pichardt!), und zwar nicht nur 
Pesnin, sondern auch in den roten Blutkérperchen (vgl. § 23. A. ILL), 
ch Liefmann u. Stern’? ist der normale Gehalt des Blutes 0,06 bis 
%o. Der Traubenzucker des Blutes stammt aus den Glykogennansey 
| Kérpers, vor allen Dingen der Leber: die mit der Nahrang auf- 
iommenen Kohlehydrate gelangen nicht sofort in den allgemeinen Kreis- 
f, sondern werden in der Form yon Glykogen in der Leber aufgestapelt 
1 von hier aus nach MaSgabe des Bedarls wieder als Traubenzucker 
das Blut abgegeben; eine sehr fein eingestelite Regulation (vgl. § 116) 
gt daftir, dab der Traubenzuckergehalt des Blutes stets innerhalb der 
malen Grenzen bleibt. Wird der Gehalt des Blutes an Traubenzucker 
‘irgend eine Weise (z, B. durch Transfusion von ‘Traubenzuckerlésang 
cine Kérpervene, durch den Zuckerstich oder Adrenalininjektion, § 116) 
iehwohl erhoht (pag. 87, Hyperglykimie), so wird der tibersehtissige 
sker durch die Nieren ausgeachieden (Glykosuric) und so der normale 
skergehalt des Blutes wieder hergestellt. Nach Aderliissen ist der Zacker- 
ialt des Blutes erhéht (Mona u. Takahashi**), auch yon der Kirper- 
iperatur wird er beeinflubt (Senator, Wacker u. Poly*, Freund a. 
rehand 6"), 


Es ist angenommen worden, daB nicht dor gesamte Traubenzucker des Blutes im 
sr Form im Binte vorhanden ist, sondern daf ein Teil dessolben an Lecithin in Form 








(eet) Chomische LOSAM Mensotzang des Blutplasmas and des Serums. 


des Jocoring gebanden sei CDrechse?*t, Baldi, Bing ™ Bag: 81); aac | 
kUnnte es sich dabei aber MOF Um einen sehr Sehr geringen any nerginy 
handeln (vgl auch Asher a. Rosenfeld **, Pyliiger 4, Michaelis 1. am, 
Siau™* fanden einen Zocker im Blut, der sih sich wie ie el Se verbielt, = 1 
wies gopnarte Glucuronshure nach, ebenso (vyorwiegend in den geformten 
Ldpine a, Boulud **, 

Bel Diabetes und den meisten experimentellen Giykosurian ist dor 2 
des Blutes erhoht (vgl. § 117), die Hyperglykiimie ist dabei die Uranche der 
Ober das Verhalton des Blotzuckers unter anderen pathologischen Verhiiltnissen v 
Rolly 0. Oppermann *™, 

Das Blotseram enthilt etwas Diagtase, woniger als Pankreassaft un 
dagegon mehr Maltase (Maltose in Dextrose Oberfihrendes Ferment) (/shmann | 
Hamburger ™, Kusumoto™"), Dio Diastase des Bintes scheint xum Teil aus de 
za stammen (Schlesinger, Wohlgemuth*, Moeckel a. Rost), xam ‘Teil an 
Leukocyten (Haberlandt ¥*). 

Nach Lépine'** hat das Blut die Pihigkeit, Zucker au zersetaen: Glyk 
UmwandInngsprodukt des Znckers entsteht dabei Milchsiiure (Ambden **), Die 
des Vorgangs ist noch unklar. 


1V. Farbstoffe. — Die gelbliche Farbe des Blutserams 
wird durch ein Lipochrom, das Lutein, bedingt, welches si 
Amylalkohol aus dem Serum ausschiitteln lit (Krukenberg), 
kommt regelmibig auch Bilirubin vor; die Menge der beiden | 
und ihr gegenseitiges Verhiiltnis wechseln sehr (Hammarsten™®*, Ga, 
v. d. Bergh wu. Snapper*), 


Y. Andere organisehe Stoffe. — Die stickstoffhaltigen 
teile nicht eiweibartiger Natur werden unter der Bezeichnun, 
stickstoff* zusammengefabt (Hohlweg u. Meyer**, Philipp**). Ir 
lichen handelt es sich dabei um Harnbestandteile; sie kommen im n 
Blute immer nur in geringen Mengen vor, da sie schnell durch « 
ausgeschieden werden. Nachgewiesen sind: Harnstoff (im Men 
bei gemischter Nahrung 0,0611°/,; im Hundeblut nach lingerer 
0,0348°/,, nach eiweibreicher Nahrung 0,1524°/,, Schdndorff 4), 
siiure, als Mononatriumsalz (Gudzent '*°), bei purinfreier Ernihrun, 
(Steinitz 8°), 0,001—0,0029/, (Brugsch u. Kristeller") und Pui 
(Bass u. Wiechowski*®*), — Kreatin (im Mittel 0,002°/,, Bek 
Glykokoll (Bingel), (Ober andere Aminosiuren im Blute vgl. 

Nach Leteche™ fehlen im Seram des Pferdeblutes: Mono- und Dia 
Harnsiinre, Xanthinbasen, 

Unter pathologischen Verhiltnissen kann die Mongo dos Reststicks 
sein (Strauss), rogelmidig bel Niereningufilclens (Hohlweg ™), Gefundan sin 
normaten Bestandtoilen: Xanthinbasen (Salkowski'®, Salomon “); Gly koko 


Tyrosin, Lysin (Newberg u. Richter, °, Bergmann uw, Langstein 6, 
Strause"), 

Von nicht stickstoffhaltigen Bestandtoilon sind nachgewiesen; Flo! 
stare (Gaglio™, Berlinerbtau™*, Fries, bei Eklamptischen Ziceifel *', 
— Bernstoinsiure, — Aceton und Oxybuttersiare (boi Dinbetes). 


VI. Wasser — gegen 90°/, im Serum resp. Plasma; im Ge 
78—80°/,. Selbst durch bedeutende Wasseraufnahme wird k 
mehrang des Wassergehaltes des Blutserams (Hydriimie) bewirkt 
eflihrte Wasser mint zuniichst in die Gewebe abgeschoben, da 
ie Niere schnell ausgeschieden (vgl. § 10). Zur Zeit der gréBte 
‘chau sogar (durch Uberkompensation) eine Konzentrationszuni 
Blutes gefunden werden (Wngel u. Scharl +3, Plehn +), 


Uber dio Bostimmung des Wassergohaltes durch refraktometrische 
untersuchung s. pag. 86. 


| Biutanalyse. 





VII. Anorganische Stoffe. Vorwiegend Natriumverbin 


Ammoniak findot sich O41—O,42mg in 1009 cate Der Gehalt des 
stets drei- bis ftinfmal groBer als der des Arterienbintes (Horedynaki, Salaskin % 
thi, Folin). — Calcinmphoaphat wird durch die kolloide Reschaifenheit pa 
temas in Lésung erhalten (Hofmeister), 





Blutanalyse. eraseeee bled Hoppe-Seyler*™ fand in einem Fall vor aa 

d einem Fall yon Melanosarkom le Zusammensetzung des Blutes; 
1000 9 Bh 10009 Scum | Btwrterper- 
cottalten ‘eaihalten chen ent- | 


SS oa 














Sea ed ue ao 183,14 | 188,86 57,76 67,68 40408 
fobin. |. 2 |) 149.60 | 129,70 | = 
davon | fader Biveilslfe - < .| |S — | = O81 
Bes Sang as 5 os) 170] 281 359] 3473} — | 
Oholestorin. 2... z 1,58 | 2.265] 128] 0,604 5.70 
ea Psds Sus itt itt Te B48 | 2,065] 2,67 1,62 
Warseranmng - ~~... + 414 3,93 4,03 248 7,72 
Alkoholausang .. 2... - 220) 1,59 1,59 x 1,59 
LY ER pe ee 6,98, 5,01 ' 7,58 = 
Trockenriickxtund 2... 203,32 | 20664 | 7746 | 85,47 = 
Wika Ration es x a4 796,78 | 798,36 | 922,54 | 914,58 — 











1000g Blut (Melanosarkom) = 321 y Erythrooyten, 679g Plasma. 


der den Trockenrlickstand-, Aschen- und KiweiOgebalt des Blutes der Neug 
Fenon vel. Schig™. — Dhar dle chomleche Zaammenselzang des Btstes (onditieth 
fo) in Krankhoiten vgl. Dennstedé , um 





Piorblat Von den xablraichen Analysen Abderhaldens'*' sion hier die folgend 
taotoilt: 


















| RRR REPEREREEe 
Rind 
808,9 
191,1 
108,10 166,9 133.4 
69,80 69,7 39,68 
0,7 0,526 1,09 
1,935 0,346 1,298, 
2,340 2,018 2,052 
0,007 611 0,681 
= 4 0,759 
Phosphorsinre als 0,0207 0,060 0,054 
Natron 3: gnawing 3,635 2.691 3,675 
RAE SW x CBS Ta sti ly lr « 0,407 2,738 0,251 
Hinsaoxya Bocce: ae Rae 0,044 0,828 0,641 
0,069 0,051 0,062 
0,064 0,052 
2,785 2.955 
Phosphorsiure . 2. 0. eee 0: 4088 1,120 0,809 
Anorganische Phosphorsiiure . . . . - O71 0,806 0,576 



































Phosphorsiure |. so. i} ods 0,240 
Anorganische Phosphorsiure 














































Wasser . . 591,858 613,15. 4 
Feste Btotfe 408,141 586,84 36 
Hiimoglobin 816,74 815,08 38 
RiweiB 64,20 56,78 

3,379 

3,748 

0,0046, 

2,2822 

0,722 

41,671 

0,0172 

1,8129 1,949 

0,7348 1,901 
































Nach H. J. Hamburger’? enthalten die roten Bintkirperchen Qateiam 
Takahaski*™ fandon in den roten Blutkirperchen von Hammel, Hand, Schwein 
0,0025—0,0035°/, CaO, Die Angaben, da die roten Blutkirperchen kein Catelum 
sind daranf xarickzufthren, da® belm Waschen mit physiologischer Kochsalx 
Calcinm ans denselben entfornt wird. 


28, Bestimmung der einzelnen Bestandteile des Bhi 


1. Bestimmung des Wassers nnd dor foston Bostandteile. 

Eine gewogene oder gomessene Mongo Serum oder defibriniertes Blut wir 
Sebiilchon auf dem Wassorbade eingodampft, einige ‘Tage im Vakanm fiber Sch 
dann im Trockenschrank bei 110—120° bis zum konstanten Gewicht getrocknot. 

Stintzing 1, Gumprecht®* wiegen m Klinischen Zwecken in einem sob 
angodeckton Glasschillchon einige Tropfen Blut, — dann trocknen sic 6 Stunde 
65°C und wiegen den Réickstand. 

2. Bostimmung des Gesamteiwe 

©. Jaksch bestimmt in 1g Blut aus cinom Schripfkopf den N-Gebalt nae 
und multipliziert die gefundene Zahl mit 6,25 (vgl. pag. 13), — Uber eine mikro 











Pathologische Veriinderungen der Zasammensetzung des Blates. 3 


Wthode zur beep tes dos Gesamt-N und des Extraktiv-N in geringen 

ong u. Lareson', a 
8. Die Brochungakrs {t des Bintserams hiingt in erster Linie von dem 

weil; t, resp. dem Wassergehalt ab, Die refraktometrische 

[fare cesta ib ea eseinese, enim /ilot xaetaien noi eee 

ithode zar Bostimmung des Eiweif-, resp, Wassergehaltes des Bintserums, Der 

effiziont schwankt beim Geannden a reac 1,352 (Strausa™, ‘Reiss, 


4. Eleqwent rood des Faserstoffes, 
ygemessenes Volumen Wlut wird mit dem Stabe goschlagen; nach | 
jit? wird allor Faserstoff anf einem Atlasfilter gesammelt and mit Wasser 
dann in einer Sebale ooo Waschon mit Wasser, Alkobol und Ather. Dann 
(110°C im Trockenofon und Wigon. — Kossler u, Pfeiffer bestimmen den 
Serum ond im Plasma (nach Kjeldahl): die Difforenz ist auf den N-Gebalt des Fibri 
bozichen. Die Fibrinmenge in 100 cm* Plasma enthiilt 39mg N (80,8—45), 

}. Bostimmung des Fottes (Atheroxtrakt), 

Dorch Extraktion des getrockneten Blutes mit Ather golingt os nicht, die Lige| 
ttmenge desselben 2u gewinnen. Zur genauen Bostimmung ist os nitig, das Bl 
lesiinre und Pepsin a verdanen oder das Blut mit der 10fachon Menge 2B pleer 
si Standen su _kochen und aus dor so gewonnensn Fliissigkeit mit 
extrahieren (Nerking*"', Fr, N, Schulz"), 

Nach Bonninger™ gentigt es fir klinische Zwecke, dag Blut in dem 10- bis 20fach) 
domen 96°/igen Alkohols anfyafangen, tichtig xn zerreiben, abzuliltrieren, den 
ehimals mit “Alkohol au oxtrabioren: man erhilt so das Fett bis auf Sparen genau; do 
t Engelhardt™ gogen dieso Bestimmung Bedenken erhoben. 

6, Bostinmang dos Tranbenznckors. 

Das Bint mnB zuniichst enteiweift werden; hierfir sind sahireiche Methoden 4 
goben worden, von denen hier die von Nona u. Michaelis *, Oppler u. Rona**, 
Frank*™ angefthrt scien (vgl. die Originalarbeiten). Die ciweiBfreie Fitasigkelt mi 
entuell noch durch Eindampfon bei sunrer Ronktion konzentriert werden; die Bestimma 
# Tranbenzuckers erfolgt schlieBlich durch Polarisation oder Titration. 


7. Bestimmung dor anorganischen Stoffe, 

Fin gewogenes oder gemesgenes Quantum Blut oder Seram wird im Platintiegel ¢ 
knet und dann verasoht. Die Bestimmung ist aber ungenau, da dabei aus dem yy 
tnnten Kiwei8 und Locithin Schwofelsdure und Phosphorsinre entsteht und mit im ¢ 
eho golangt. 















29, Pathologische Veriinderungen der Zusammensetzung 
des Blutplasmas und des Gesamtblutes, 


1, Vormohrter Wassergebalt des Blates resp. des Blotplasimas findet sich ¥ 
om hiinfig boi don Blutkrankhoiton, x. B. don Ankmion, bei pernizidser Aniimie, selten 
| Choroso, Bei Herzkrankheiten nnd Niorenentzindungen kann der Wasa 
halt dos Bintes normal sein, beim Anftreten von OGdemen wird uber auch das Bi 
wssorreichor. Nicht immer geht der Wassergehalt des Blutes und des Blutserams paral 
| dor perniziésen Aniimie steigt der Wassergehalt des Serams in viel geringerem Gra 
{ dor dos Gesamtbintes. — Cher dio Bestimmung des Wassergehaltes des Blutseray 
rch dio refraktometrischo Bintuntersuchang und ihre Resnltate in Krankheiten 
arting . 
Kine fibermabige Bindickung des Blotes durch Wassorvertast wird beim Mensch 
ch roichlichen, wisserigon Durchffllen, namentlich boi der Cholera, beobachtet, #0 di 
5 toorartige, dickilissige Blut in den Adern stockt. Auch reichliche Wasserabgabe dar 
) Haut bel Schwitzkuron, zomal bei gleichzeitigem Mangel an Gotrink kann Verminderat 
a Wassergebaltes des Bintes, wenn auch nur in miifigen Graden, hervorrafen. Tm eine 
He von hochgradiger Lipianie bei Diabetes beobachtete B. Fischer*"* einen Wassorgoha 

Bute von nur 69,636"),, im Serum yon nar 69,287°, 

2. Sind die BiweiBkorper des Blutes abnorm vermindert, so pilegt am thy 
jie Ubermidiger Wasserreichtam des Blutes cinzutreten; dann sind auch die Salze ad 
ismas vermindert. Eiweilveriuste geben die direkte Ursache ab: Albuminurie, andameend 
terungen, umfangreiche nissende Hautilichen, hochgradige Milobverluste, eiweibaltig 
trebflille (Ruhr). Aber auch hiufige und umfangreiche Blatungen bringen, da der Verlm 
nilchst vorwiegend durch Wasseraufnahme in die Gefide gedeckt wird, im Anfange ciz 
irminderang der Riwoifkirpor des Blutes harvor. 








13aV4 MAveratnr (g Z3—Z9. 


BL eats epee fs erate ep Sahaesndios wir ee 


boi Fettaiioh ‘you Diabetes (bis 2u 18"/,! Fett, darar 
Cholestarin. siete or Bieler tad ole Das Blot hatto das Ausschen » 
golbweiGom B, Fischer", Neisser 0, Derlin®, Barger u. Beum 


Klemperer 1. Umber "* berabt die dinbetische Liplimie nur zum Teil wirl 
vermehrung, zum Teil auf Vermehrung des Cholesterins und Lecithins. — Kine 
Vermehrung des Cholesterins und Lecithins fand J. Miller*™ im Blnte eines 
snbakuter Nephritis. 

Nach Verletzungen der Knochen, welche das Fettmark treffen, gelangen of 
Fetttropfon von den 2, ‘. wandungslosen Gefiidon des Markes aus in die Bluth: 
es sogar zom Ubertritt in den Harn und za lebensgefibrlicher Fottembo 
Langen kommt, 


4. Hyperglyk&mia. Ist ans irgend cinem Grande der Znckergebalt 
uber die Norm erhébt (bei Diabetes), so. wird der Zucker durch dio Nieren am 
Giykosarie, Die Lins trt sich wogun des Zuckengealies der Angenftssgkeite 
heilen schlecht wegen des abnorm gemischton Blutes. Farancnlose, Gangriin, Pr 
position zur Tuberkuloge werden ebenfalls auf den erbohten Znckergehalt dex Bh, 
gofihrt, 


Literatur (§ 24—29). 


1. Zuxammenfassende Darstellung: P. Morawitz: Die Chemie d. Bh 
¥, P. 4, 1905, 307, Die Gerinnung des Blates, C. iheimors Handb, d. Biochemie 
IL, 2, 40, — 2, Britcke: ¥, A. 12, 1857, 109, — 3, BE. Unger: ©. P, 26, 191i 
4. Freund: Wiener med. Jahrb, 1886, 46—48, Wiener med, Blitter 1891, 
5. Arthus a. Pagis: A. dP. (5), 2, 1890, 739. — 6. A. Schmidt-Matheim: A.T 
— 7. E. P. Pick u. K. Spiro: %. ph. Oh, 31, 1900, 285, — 8, Albertoni: C1 
Nr. 36. — 9 Salvioli: 0, m. W. 1885, 913. — 10. A. Mosxo: A. P. P. 25, 18 
11. H. Conradi: WB. 1, 1902, 136. — 12. F. Franz: ALP. PL a, 1905 
13. Sabbatani: A.i. 3. 31, 1899, 875. — 14. Loch u. Smith: Zentralbl. f. Bakte: 
15. F Morawits: D, A. k. M. 80, 1904, 340, — 16. J.P. Pawlow: A. P. 18 
17. Ch. Bohr: C.P, 2, 1888, 261. — 18. Krager: Diss. Dorpat 1886. 

%. kM. 56, 1905, 264. DA kM. 99, 1910, 518. — 20. P. Morawits uv. 
DA. kM. M, 1908, 110. — 21. P. Morawite a. R. Bierich: A. P. P. 56, 1% 
22. Dastre u. Florexco: Or. soc, biol, 48, 243 0. 358. A. d. P, 28, 402. — 28 
Gey: ©. r. soc. biol. 50, 1041. — 24. Sackwr: Mitt, aus d. Gronag. d. Med. a. 0 
25. Zibell: Mm. W. 1901, 164: 20. K. Barker: P, A. 102, 1904, 36. 
452. 149, 1912, 318. 27. Arloing: OC. r. soe. biol. 58, 675. — 28. Arthus 
s 273, — 29. Milian: 0. r. soc. biol. 58, 703. — BO. R. ron den Velden: A. P.! 
37. — Si. K. Biirker: P. A. 118, 1907, 452. — A. Schmidt: ALA. PB. 1 
Om. 1871, Nr. 48, P. A. 6, 1872, 413, 9, 1874, 383. 11, 1875, 201 0. Std 
103 0. 146, Die Lebre von den fermentativen Gerinntingserscheinungen. Dorpat 
4, 1890, 267. Zur Blutlobre, Leipaig 1892. Weitere Beitriige x. Blntlehre. Wies! 
~ 33. 0. Hammaraten: Untorsnchungen aber die Faserstoffgerinnung. Nova Ac 
Sciont. Upsala (3) 10, 1875, 1. P. A. 14, 1877, 211. 17, 1878, 413. 15 er 3 
563. 22, 1880. 431. 30, 1883, 437. Z. ph. Oh. 22, 1897, 333, 28, 1 
Heubner: A. P,P. 49, 19038, 229. Z. ph. Ch. 45, 1905, 855, — 35. W. Tabor 
44, 1905, 182, 46, 1905, 273. — 36. F. Mittelbach: %. ph. Oh. 19, 189 
87. BT. Millers WB. 6, 1908, 454. S. W. A. 115, TH, 1906, 229. — 38. GH 
A. J.P, 83, 1914, 0, — 30, E,W. Goodpastui |. P. 38, 1914, 70. — 40. 1 
u. B Behn P,P. 58, 1908, 141, — 41. B. Fuld a. K. Spiro: IL B. 5, 1K 
42. P. Mor 79, 1904, 1. HL. B. 5, 1904. 133. 43. Arthus: 
sar In cougnint. du sang. Thiso, Paris 1800. J. d. P. 7, 1901, 887. C.F. soc. biol 
962 uw. 1024. — 44. W. Cramer u. H. Pringle: Quarter. journ. of Physiol. 6, 1 
45. KL Fuld: 0, P. 27, 1903, 629. — 46, Dastre: 0. ¢. soe, biol. 45, TL, A.d. P. 
47. G. Corin a. G. Ansiour : V. g. M. 3. Folge, 5, 1893, 234. 7, 1894, 80, — 48. 
7%. ph. Ch. 30, 1900, 174. — 49. P. Morawite: 1. B. 8, 1906, 1. — 50. Bordet 
Annal, de l'Institut Pasteur 17, 822. — 51. P. Morawite: D. A. k. ML 79, 1% 
52, A, Schittenhelm a. A. Bodong: A.P. PY. 5A, 1906, 217. — 53. Hédon uv. 
©. ¢. aoe, biol, 48, 1896, 633. — 54. BE. Gleyu. V. Pachon: A. a. P. 27, 711. 
716, 0. e121, 1895, 883, 122, 1896, 1220. 0. r. soe. biol. 48, 1896, 523. — 5h. Zi 
faseende Darstellung: O. Hammaraten: B. P. 1, 1, 1908, 380. — 56. O. He 
P. A. 17, 1878, 413. 18, 1878, 38. BO, 1883, 497. — 57. @. Kawder: A. P.P 
411. — 58. Predérieq: A. B. 1, 1880, 17, — 59. HE. Fuld u, K. Spiro: Z, ph. 0) 











































Litoratur (§ 24—29), es 


4 — 60. BP. Pick: HB. 1, 1902, 361. — 61, B. Freund a J. Joachiae CP. 

i Ne aoe 62, 0. Porges u, K. Spiro: H. B. 8, 1903, 

€. A, Peketharing: 0, P. 9, 1895, 102, — 64. G, Liebermeister: H, B. 8, 1 

65. B.S, Faust: A.P, P. 41, 1898, 309. — 66. Giirher: Sse eo Phys 

3, Ges, 1894, 143. — 67. Michel: W.V. 20, 1895, 117. — 68, W. yurton 

ae 5, 1884, 162. (886, 319. — 69. J. Lewinski: P. A. 100, Toe, eu. = 
cin w Me Mayor: bea toate 69. Pak fi eee 1905, Heft 





he 
= PSB Abderhatden v. Mitarbeiter 7, ph. Ob. 42, 1904, 155. 51, 1907, 

‘2473. 88, 1913, 478, B, a 8, 1908, 368, Tet, d. physiol, Ohemie, 3. Auth, 1. ‘Feil. Berti 
Wien 1914. 8. 506 u. 540, A, Costantino: BZ, 55, 1913, 411. — 7% 2. Untenhath 
Weidanz: Prakt. Anleitung x, Ausfihr, d. blolog. Riweidiffarenziorangsrerfahrens, Jen 
. — 80. B. Abderhaldens. Abwobrfarmente 4 tier. Organ. 3. Aufl. Berlin 1913. = 
\ BE, Weinland: Z. 8. 47, 1906, 279. — 81. 8. G. Hedin: J. 0, P. 30, 1903, 195. = 
M. Engethardt: D. A. . M. 70, 1901, 182. — 83. Bonninger M 

B. Neisser n. H. Bracuning: Zo. ¥. u. 7. 4, 1907, 747. — 85. Laites! A. PLB. 64 
1, 132. — 86. M. Bleibtreu: P. A. 85, 1901, 345. — 87. Fr. N. Vesna P. A. 6 
7, 209. — 88. K. Harthle: Z. ph. Oh. 21, 1896, 331. D.m. W. 1896, 507. = 
E. Hepner: B.A. 78, 1898, G03. — 90. B. Letsche: %. ph. Oh. 68, 1907, 110. = 
M. T. Fraser u. J. A. Gardner: P.R.8. 81, B, 1909, 230, — 92. L. Wacker a. We 
BP. 74, 1918, 416. — 93. F. Rdhmann: Bek. W. 49, 1914, 1993, — 9. Wea 
4. Funk: Mm. W. 1913, 28. — 9. F. Tangl u. 8. Weiser: P. A. 115, 1906, 12, = 
W. Cohnstein w. Ht, Michaclia: P. A. 65, 189%, 473, 69, 1898, 76, BP 3, 1, 1904, 21 
97. Hanriot: ©, x. ae. ta 48, 1896, 925. ©. r, 128, 1896, 763. 124, 1897, 778, 7 
thaelis u, P. Rona: B, 7%, BA, 1911, 345, 83, 1911, 413, 39, 1912, 21. G, Jeans B.D 
1912, 390, — 98, E. Abderhalden u, P. Rona: %. ph. Ch. 75, 1911, 30. BE. Abderhalde, 
4. E, Lampé: 2. ph. Ob. 78, 1912, 396. — 99. J. H. Schultz: B.%. 42, 1912, 255. = 
). Zuxammenfassende Darstellung: J. Bang: Der Biutaucker. Wiesbaden 1913. 
~ M. Pickard: % ph. Oh. 17, 1893, 217. — 102. KE. Liefmann u. R. Stern: B.%. 4, 1901 
1. — 108. P. Rona a, D, Takahashi: B. 2. 80, 1910, 9. — 104, Senators Za ik. Me OF 
19, 258. — 108, L. Wacker u. FP. Poly: D. A. ke M. 100, 1910, 567, — 106, Hf, Fire 
F, Marchand: A.B. P. 73, 1913, 276, — 107. B. Drechsel: Ls B. 88, 1886, 44. dey 
N.P ae tn 425. — 108. D. Baldi: A, P, 1887, Suppl, 100, — 109. H. J. Bing 
32) 11 — 110. P. Mayor: B.%. 1, 1906, 81. 4, 1907, 645. — 111, 1, Ashe 
R Tiowenfeld ah P, 19, 1905, 449. B, %. 8, 1907, B35. — 112. B. Rflager: PA. 1M 
Vi, 217. — 118. L. Michacliv u. P. Rona: B.Z. 14, 1908, 476. —' 114. FW. Poe 
BL, Sian: J. 0. P. 26, 1901, 28%. — 115. P. Mayer: %. ph. Ch. 32, 1901, 548. = 
5. KR. Lépine a. Boulud: ©. r. 185, 1902, 139. 141, 1905, 453. Jd. P. 7, 1905, 775. = 
1_F. Rolly n. F. Oppermann: B. %. 48, 1913, 269 n. 268. — 118. F. Rohmawn: B. ad. eb. € 
a BG4. 27, 1804, 3251. — 119. M. Bial; P. A. 52, 1802, 137. 58, 1893, 104 

1893, 72. — 120. C. Hamburger: P. A. 60, Ch, Rusumoto: Boo 
1908, 217. — 122, Schlesinger : W, 1908, 598 . Wohlgemuth = Bi. 4 

1909, 381 n.423, — 124. K, Moeckel u. F. Rost: . 67, INO, 43S. — 
1. Ln, Haberlandt: P.A. 182, 1910, 175. — 126, R. Lép 110, 1890, ua. Ds x 
. Embiden a. Mitarbeiter; B, Z. 45, 1912 
g: Sitz.-Ber, d. Jonaischen Ges, f, Med. a. Naturw, 1885, 52 (Supp). 2. Jen; AS 3 Baltac 
iatarwiss. 19, 1886). — 129. 0. Hammarsten: M. J. 8, 1879, 129. — 130. Galleran 
i, B. 48, 1905, 389. — 181. A. A. Hymans 0. d. Bergh no J. Snapper: D.A. ke Me TA6 
a — 182. H. FoMiwig a. H. Meyer: HB. 11, 1908, 
































































itz: D. mW. atoll, 19. %. ph. Ch. 90, 1914 
4. — 187. Th. (Ran u. L. Kristeller: D. mW. 1914, 746, — 138, 2 Bass nH 
‘echowski: W. k. W, 25, 1912, 1863. R. Bass: A. P,P. 76, 1914, 40. — 139. J. C. Baker 
oh. Ob, 87, 1913, 21. — 140. A. Bingel: Z. ph. Oh. 5%, 1908, 382, — 141, Stranene 

, chron, Niorenentzindang in ihrer Kinwirkang auf die Blutflissigk. Berlin 1902, — 

H. Hohlweg: D. A. k. M. 104, 1912, 216. — 143, Salkowski: V. A. BO, 174, — 144. @ 
Gao 2 ph. Oh. 2, 1878, 65. — 145, Newberg un. Richter: D. mW. 1904, 490. = 
4. Ge. Bergmann u, L. Langatein: H, B. 6, 1905, 27. — 147. C. Newberg u, Hi. Strauas 
k. W, 1906, 258, — 148. @. Gaglio> A. P. 1886, 400. — 149. M. Berlinerblaw: A. PB 
ice: B.Z, BB, 1911, 368. — 151. Zweifel: Arch. f. Gyn. 76 
M. m. W. 1906, 297, — 152. J. Donath: B. k. W. 1907, 241. — 158. Bago 
Zk. M. 60, 1906, 225. — 164. A. Plehn: D. ALK. M. 91, 1907, 1. — 
4. W, Horodynski, S. Salavkin uw. J. Zatesk : 56. 0, Folin 



























($30) Dio Gase des Bintes. Physikalische Verbemorkungen. 


%. ph. Ch. 87, 1902, 161, — 157. Fe. Mi ae ige e oS 
Seyler: Modobem. Untersueb. 1 ih 6% he 8 0 i ee 
£. Kinderheitk. 64, 1906, 409. — 1 GO, Dennstedt 








yi, ans d. Vtiand 
krankenanstalten 8, 1900, 1. ZkM, 58, 1905, 81. — il, Ey Abderhalden: %, 
1898, 106. — 162. H. J. He 4 
DT 
267, — ke 
49, 1913, 19. 51, 1913, 193. — 167. Stravse: Die chronischen 


ny 
Kinwirkung anf die Bluititissigkeit, Berlin 1902, der Gegenwart. 1903 
1905, Nr. 2, Vereinsboilage. %. k. M. 52, 1904. — 108. £. Reise: H. B. 4, 1904, 1 
BA, 1904, 18, — 169, Martins: Diss. Berlin 1906, A. Bdhme 
— 170, Kossler w. Pfeiffer: te ke Me B83, 1897, 225. — 171. J. Nerking: B.A 
172. — 172. P. Konia wi. Ly Michaelis: Bs he 2, 1908, 329. B, 1908, 356, 14, 1 
173. B. Opler w. P. Rona: BZ. 18, 1908, 121, — 174. K. Moeckel a. B. Frank 
5, 1910, 528. 6%, 1910, 85. — 175. 2. Fi 1 
u. Derlin: %. kM. BA, 1904, 4 7. Barger 

Ti Klemperer u, Unbers ZEAL 6 61, 1907, 145, 65, 1908, 40. — 179. 
%. ph. Oh. 36, 1913, 469, 








30. Die Gase des Blutes. Physikalische Vorbemerk 


Dic Menge cines Gases kann gemessen werden nach dem Volumen (in 
metern) oder nach dem Gewicht (in Grammen), Das Volumen, welches eine 
Gasmenge cinnimmt, hingt ab von dem Druck und der Tomporatur. Nach | 
Mariotteschen Gest ist das Volnmen cines Gases umgokehrt proportional dem 
dem 2fachen, Sfachen . ... nfachen Drnck betriigt das Volumen also ') he 
Nach dem Gay-Lussacschen Gesetze nimmt das Volumen einos Gases bei Ee 
‘Temperatar om 1° 20 um "/,,, des Volumens bei 0°; cine Gasmonge, welche 
Volumen 273 em? hat, hat also bei 1° das Volumen 274, und bei 10° das Volum 

Im folgenden wird die Monge eines Gages stots nach dem Volumen bei 0° 9 
Drock angegeben werden. 

Wird eine Flissigkeit mit einem Gase in Berihrung gebracht, so nimmt 
keit einen Teil des Gases in sich auf. Dabei kann das Gas in zweifucher, stren 
scheidender Weise in der Flissigkeit enthalten sein, niimlich einfach physik 
sorbiert oder chemisch gebunden. Enthiilt dio Fiiissigkeit keine Snbstan 
mit dem Gaso chomisohe Verbindungen singchen, so findet einfache physikalische 
statt; sind dagegen golche Substanzen vorhanden, so erfolgt anBer der physika 
sorption dea Gases in der Flissigkeit auch noch die chemische Bindung des G 
dazn befthigten Substanzen. 

Wird eine Filissigkelt (die kelne das Gas chemisch bindenden Substany 
mit cinom Gase gosiittigt, ao ist die nbsorbierte Gasmenge direkt proportional den 
der Flissigkeit und dom Druck dos Gases. Als Absorptionskooff 
zeichnet man cine Zabl, welche angibt, wieviel Kubikzentimoter Gas 1 em? Fis 
nimmt, wenn diese bei 760 mm Drack mit dem Gase gealttigt wird. Der Absorption 
nimmt mit steigender Temperatur bei den verschiedenen Gasen in sigenartige 
er muB fir die verschiedenen Temperaturen empirisch bestimmt werden, Der 4 
kooffiziont {Mr die Absorption in destilliertem Wasser bei 40°C botriigt fiir 
0,0231 ( Winkler"), Kohlensiiure 0,530 (Bohy*), Stickstoff 00118 (Bohr u. Boel 
dio wisserigo Flissigkelt feste Stoffe geltist, so wird dadurch der Absorptio: 
herabgesotat; diose Erniedrigung betrigt ffir Blutplasma aber nor 2,5°/, des Wert 

Steht sino Flissigkeit mit oinem Gasgemisch in Berhbrnng, so absorb 
cinzelnen Gase des Gemigchos ontsprechend ihrom Partinrdruck. Gnse fiben 0 
gar keinen Druck aus. In einem Gasgemisch kommt daher von dem Goxamtdrne 
anf jedes cinzelne Gus soviel (Partiardruck des cinzelnen Gases), als dem Volum 
entspricht. Enthiilt also z. B. Lnft von Atmosphirendruck 21 Volumenproa 
stoff und 7% Volumenprozent Stickstoff, so betriigt der Partiardrock dos 


a “100 = 159,6 mm ond der des Stickstottes “9:70 — 60044 mm. Ist dig Taft » 


100 
30 ist vom Gesamtdrack znerst der Drack dos in der Luft onthaltenen Wasser 
Abgug 2n bringon. 
Absorbiorte Gase entweichen ans der Fiissigkeit: 1, Im Vakaum, 
rorblerto Gasmenge dem Dracke proportional ist, ist sie beim Drack O obenfal 
2 Beim Durchleiten eines andoren indifferenten Gasos, Stoht die 





, Gowinnnng und Untersuchung der Bintgase. 


wr mit einem anderen Gase in Berthrang, so ist dor Partinrdruck fiir das absorbie) 
as natirlich wiederum gleich 0. 3, Beim Erhitzen dor Fllissigkeit bis =n 
ledepunkte. Der Absorptionskooffizient nimmt mit steigender Temperatur ab und wi 
im Sieden dor Flissigkeit gleich 0. 

Enthillt die Flissigkeit Substanzen, welche das Gat chomisch xu binden vermige 
wird nattrlich auBer derjenigen Gasmenge, welche von der Flissigkeit physikatisch a 
rbiert wird. noch so viel mehr von dem Gase aufgenommen, als die in der Fitssigk: 
handenen on chemisch binden kinnen, Die chemiache Verbindung zwischen di 
der Fifissigkelt enthaltonen Substanzen und dem Gase kann non sein entweder eit 
iste oder gino digsoziable. Kine feste Vorbindung ist unabhingig vom Druck; 4 
ird daher im Vakuum nicht zerlegt, sondern kann nur durch chemische Mittal gelost werde 
2 Gogensatz dazn bexeichnet man als dissoziable Verbindungen solche chomische Ve 
ndungen ciner Substanz mit einom Gase, die abhiingig sind vom Druck und daher # 
akuum zerfallen. Bei einem bestimmten Druck verbindet sich alle vorhandene Substa 
it dom betreffonden Gas, sinkt der Druck, so bleibt nur noch cin Brochteil der Sabsta 
chemischer Bindung mit dem Gase, cin anderer Teil ist unverbunden, bei weltere 
nken dex Druckes wird der Bruchteil der Substanz, der noch Gas gebanden hat, ime) 
einer und beim Drncke 0 ist nur noch unverbundene Sobstanz vorhanden, 

Boispiol: Leitet man dorch cine wiisserige Natronlange CO,-haltige Luft, 30 wi) 
e Koblensiinre von der Pitissigkeit anfgenommen, und zwar wird 1. ein Teil der Kohle 
uro physikalisch absorbiert vom Wasser proportional dem Absorptionskoefiizienty 
d der herrschenden Temperatur, der Menge des Wassera nad dem Partiardruck der Kohle 
ure; 2. ein anderer ‘Teil der Kohlensiinre wird chemisch gebunden, niimlich a) fe: 
sbundon als Natriumearbonat; nach der Formel 2Na OH + 00,—Na, 00, +H, 0 bind 
Molekitle NaOH 1 Molokiil CO,, diese Rindung ist ganz unabhingig vom Druck; }) diss 
abel gebunden als Natriumbicarbonat; nach der Formel Na, CO, +00, + H, 0—2 NaH OC 
‘ese Verbindnng ist abbiingig yom Druck. Nach Bohr * waren in einer 0,15%/igen Léwmt 
m Natriamearbonat bei 37° Durehleiten von CO, als Bicarbonat vorhanden: 98' 
i atnee CO,-Spannung von 12,53 mm, nur noch 83°), bei 1,0 mm, 66%), bei 0,3 mam, 47! 
i OL mm. 

Die physiologiseh wichtigon Gage dos Blutes (0 und 00,) sind an 
:iBten Teil im Blute chemisch gobundon vorhanden, und zwar in For 
ssoxiubler Verbindungen. 














31. Gewinnung und Untersuchung der Blutgase. 


Dio Austroibnng dor Gase ans dem Binte und die Aufsamminng 2»! 
tomischon Anulyse goschioht vermittolst dor PAdgerschon Quocksilber-Luftp um} 
g- 20). 

Der Blatrezipient (A), cine 250 bis 300cm® fassende Glaskugel, verjlingt si 
en und unten in Rohre, welche durch Hihne @ und b verschlossen werden kinnen. Hahn 
{ein gewohnlicher Sperrhahn, der Hahn a jedoch hat eine durch die Liingsachse vi 
afende, bei  ausmiindends Durehbohrang der Art, da diese je mach der Stelling « 
oder in den Reziplonton fihrt (Stellung 2@) oder nach abwiirts darch das untere Ro 
itot (Stolinng 2a’), Dioser Rezipient wird auerst (mittelst der Quecksilberluftpampe) vill 
Aftleor gemacht and nun gewogen. Hierauf bindet man das Ende a* in oine Arterie od 
me cines Tieros und Ii8t nun bei der Stollung des unteron Hahnes xa Blot in den R 
pionton einstrimen. Ist die nitige Mengo hineingelassen, so gibt man dem unteren Hahi 
oder die Stellung ix’ a’ (stinbert finferlich alles sorgfiltig) und wagt nun den Rezipiente 
o die Gewichtsmenge des cingelassenon Blates zn bestimmen. — Der zweite Teil @ 
oparates ist das Schanmgefai® (8), ebenfalls oben und unten in Réhren auslanfen 
mit Sperrhihnen ¢ nnd d yersehlossen werden kinnen; o dient zum Auffangen dy 
irch die stiirmisehs Gasentwicklung ans dem Blute sich bildenden Schaums. Durch Seblif 
aht das Schanmgofi nach unten mit dem Rezipienten in Verbindung, nach oben mit det 
« Trockenapparat (G). Dieser ist eine U-fermige Robre, anten mit einem Glasballot 
stutorer ist halb mit Schwofelsiure gefillt, in den Schankeln liegen Rimastelnstficki 
it Schwofolsiure getriinkt. Die Blotgase geben hier alle mitgefuhrien Wasserdampd 
(die Schwofelsiiure ab, so da sie villig trocken darch Hahn f woltergefibet 
imnon. Es folgt das kurze Rohr D mit der kloinen Burom'sterprobe y, an welcher ma 
m Grad der Lnftleere nblosen kann. — Von D gelangen wir zur cigentlichen Pamy 
drrichtung. Diese besteht aus zwei groBen, oben und nnten in offone Réhren auslanfende 
askugeln, deren untere Rihren Z und w durch einen Gummischlauch @ yerbunden sin 
side Kagel und der Schlauch sind mit Quecksilber bis zur halben Hohe der Kageln ay 
fillt, Dio Kugel # ist befestigt, die Kagel F kann durch eine Windevorrichtang am Gy 














Schoma dor Pfayerschon Blut Enigasangspampe. 


in der Stellung H die Kugel £ mit ABGD in Vorbindung setet, in der Stellun 
ABGD absporrt und nan die Kugel E mit dem Rohro J verbindet. 

Es wird nun suerst BGD vollig luftloor gemacht in folgenden Akton: Habr 
Hobang yoo F, bis Tripfchen Quecksilber aus dom freien Rohro 4 (das noch ni 
gebracht ist) in die Wanno lanfon, — Habnstollung H, — Sonken von ¥, — Hahi 
— und so weiter, bis die Baromoterprobe y die Evaknation anzeigt. Nan wit 
gebracht. Offnet man nun die Hthn ¢ und 0, so daB dor Rexipiont A mit dem fbriy 
kommuniaiert, so stirzen unfschiinmend dio Blutgase in B und durch @ 

E, Senkung von F' bringt sic zumeist in £, Nunmehr Hahnstellung K nnd Hel 


a 


Quantitative Bestimmung der Blutgase, Sauerstoft im Bute. [est 


ngt dio Gase in J fiber Quecksilber, Wiederholte Senkung und Hebang von F mit passe) 
‘Habnstelling bringt scblieBlich alle Gago in J. — Dio Entgasung des Blates: aa 
sentlich befordert durch Kinsenken dee Rezipienten A in einen Keasel mit 60° 0. 


weaer (pag. 8), 

Ober’ ain ein cinfuches Verfahren (,.Perricyanidmothode*), ohne bay ot 

t Sanorstoffgehalt des Blutes quantitativ xu bostimmen, vgl. Haldane*, 

reroft u. Morawitz*. is ta Fo 
Mayow (1670) sah zerst Gnse aus dem Bh im Vakoum 

iestley wies in diesen ©, sowie Dacy 00, nach. Magnus (1837) untersachte 3 

zentische Znsammonsetzung der Blutgase. Die wichtigen neueren Untersuchungen sin 

sentlich von Lothar Meyer (1807), der C. Ludwigschon und der Pylagerschen Schl 

igefihrt worden, 


Quantitative vita vag der Blutgase. Dio Blntgase bestehen aus O, GO, and? 

Die nusgepumpten Blutgase befinden sich in dem Endiometer-Rohre (Fig. 20, J 
om genan kalibrierten Gluwrohre, in desken oberer geschlossener Kuppe 2 Platindrith! 
n) eingeschmolzen sind. Das Budiometer ist unten durch Hg abgesperrt, 


1. Bestimmung der CO,. — Man bringt von unten durch das Quecksiber in a 
sgemenge hinein eine, an einen Platindraht gegossenc Atzkalikagel, die an der Obe 
the befeuchtet ist. Die OO, verbindet sich mit dem Atzkuli zu Kalinmoarbonat, Nae 
gerem Verweilen wird die Kugel auf demselbon Wege wieder herausgezogen, Die Vo 
adernng des Volumens der Gage zeigt das Volumen der wegeenommenen CO, an. 


2. Bestimmung des 0. 

a) Abnlich wie eas Bestimmung dor CO, fihrt man mittelst eines Platindrahtes eit 
osphorkagel, welche den Q unter Bildung von Phosphorsiure anfnimmt, oder eit 
ekene Koks- oder Papiermachékugel, getrinkt mit siner Lisang von Pyrogallass&at 
Kalilange, wolehe © begierig an sich reibt, in die Fudiometerrohre. Nach Entfernar 
«Kugel zeigt auch hier die Volumenverminderang der Gaso die Menge des O an. 

b) Am genanesten und schnellsten wird der O durch Verpuffen im Budiomet« 
itimmt. Man fibrt in die Endiometorrdhre reichlich H ein, dessen Volumen gent 
ttinmt wird. Hieranf Hit man einen clektrischen Funken zwischen den Driihten p und 
teh die Réhre schlagen; O und H verbinden sich za Wasser. Hierdurch entstebt ¢b 
lumenverkleinerang im Endiometer, von woleher der dritte Teil anf den zur Wasse 
Jung (4, 0) verbranehten O entfillt, 


3. Bestimmung des N, — Sind nach den obigen Methoden OO, und © ang de 
sbehiilter entfernt, so ist der Rest N. 





32. Sauerstoff im Blute. 


I. Sanerstoff — ist im arteriellen (Hunde-) Blute im Mittel ron 
20 Volumenprozent vorhanden (in 12 Versuchen fand Pfliiger® 18,7 b 
‘4 Volumenprozent). Durch sehr ausgiebige kiinstliche Respiration by 
eren (in der Apnoe) oder auch durch starkes Sehiitteln von Blut m 
uft kann das Blut vollstiindig mit Sauerstoff gesiittigt werden; das arté 
‘He Blut ist in der Regel nicht villig, aber doch beinahe mit Sauersto 
siittigt (Pylager). Im vendsen Blute sind im Mittel 8 Volumenprozen 
miger als im. arteriellen, also rund 12 Volumenprozent Sauerstoff enj 
ten, doch wechselt die Menge des O sehr nach den Geweben und de 
seislaufsverhiiltnissen; in dem Blute ruhender Muskeln (fand Sezelkow? 
Volumenprozent; im Erstickungsblute sind nur noch Spuren vorhanden 
dem stiirker geréteten Blute titiger Driisen (Speicheldrtisen, Nieren) is 
otz. des erhihten Sauerstofiverbrauches der Organe infolge der Vermehrun 
5 Blutzuflusses (Vasodilatation) noch mehr Sauerstoff vorhanden, als in 
wohnlichen dunkleren Venenblute. 

Der O kommt im Blute yor: 


a) Physikalisch absorbiert, und zwar vom Plasma: nur eit 


imaler Teil des gesamten Sauerstoffes, Wasser nimmt aus atmo 
ischor T.nft 0A Valnmennrazent anf: da das Plasma qoliicte Snhetanee 








1852] ‘Sauerstof? im Blute. 


enthalt, welche die AbSorption herabsetzen, wlirde der Maxima 
den physikalisch absotbierten Sauerstoff noch unter 0,5 Volum 
liegen. “Die Menge des absorbierten Sauerstoffes ist natlirlich pri 
dem Druck. 
- lak Sey eaten LAC eed EI O dé 
Loth. 1 1857), und zwar an das Erythroeyten 1 
so. ach Hilfner® kann 1g Hb 1,84¢m® Sauerstoff bin 
einem Hb-Gehalt von ee wlirde das einem Sauerstoffgehalt d 
von 14, 1,34 = 18,76 Volumenprozent entsprechen. 

Die Verbindung des Sauerstoffes mit dem Hiimoglobin ist 
soziable Verbindung (vgl. pag. 90), also abhiingig vom Druck: im 
zerfullt sie und gibt allen Sauerstoff ab. Die vom Hb gebunde! 
stoffmenge steigt aber nicht proportional dem Druck (wie bei 
lischer Absorption) und ant schon bei der Spannung der Ss 


in der atmosphirischen Luft fast das Maximum. Die folgend 
(nach Hifner**) gibt an, wieviel Prozente des Hb des Blutes 
schiedenem Partiardruck des © als gasfreies Himoglobin resp. ( 
globin yorhanden sind (bei 13°/, Hb-Gehalt und 37,4° C): 


























Partiar- | taro- 
Stuceeifes| atnnd in | ————————— svermoftes 
imme Hg | wm 3g | Hamo- | Oxxhamo- |g mm Mg iisé- | 
a0 23,8 63,9 361 | 700 | 3340 115 
10,0 47,7 47,6 524 73,0 | 357,8 10.8 
15,0 71,6 87,7 62,3 || 80,0 381,7 10,2 
20,0 954 31,2 68,8 || 85,0 40,5 ae 
25,0 119,83 26,7 73,3 90,0 | 4204 92 
30,0 143,1 23.3 76,7 95,0 | 453.2 87 
35,0 167,0 20,6 4 100,0 ATA 8a 
40,0 190,8 18,5 81,5 1100 | 6248 76 
45,0 214,7 16,8 83,2 1200 | 872.5 10 
50,0 238,5 154 BAG 130,0 | 620,2 6,5 
55,0 262,4 M43 85,7 140,0 667,9 61 
60,0 286,2 13,2 86,8 150,0° | 715,6 57 
65,0 310, 12,3 87,7 1600 | 763.3 54 























%n etwas anderen Werton kam Loewy"; or fand fir dic Sittigung dos B 
(dio aus atmosphiarischer Luft anfgenommene Mongo == 100%, gesetat) bei vo 
Partiurdruck dos Sanerstoffes dio folgenden Zablen: 






‘Sauorstoffpartiar- 
ruck wm Hg 





















8,77 





‘Sattigang: 44,52 5 | 62,40 TAL | 77,8 





67,29 | 71,09 





Danach wirdo bei nioderen Werten des Snuerstoffpartinrdrackes cim 
atirkero Dissozintion des O,-Hb stattfinden als nach don Hafnerschen Angaben. 
betont Loewy das Vorbandensein individueller Unterschieds in der D 
spannung des O,-Hb des Menschenblates. 

Bei dem Sauerstoffgehalt der atmosphiirischen Luft und 3 
Barometerstand wird also schon fast alles Hb in O.-Hb umgewand 
Atmen in reinem Sauerstoff kann daher nur wenig mehr 0 yom | 
genommen werden als beim Atmen in gewbhnlicher Luft. — Ai 
zeigt die Tabelle, daf erst bei sehr stark erniedrigtem Partiard 


t Sauerstoff und Koblensiare im Blate, [83 





auerstoffes cin erheblicher Teil des Hb keinen O mehr bindet. Dara) 
‘Kluirt es sich, da6 Tiere, die in einem abgesperrten kleinen Raum atme 
as demselben bis zur Erstickung fast allen O bis auf Spuren in il 
lut aufnehmen, da6 auch in verdiinnter Luft (hohe Ballonfahrten, Aufentha 
af hohen en) der notwendige Sauerstoff aufgenommen werden kan} 
rst bei sehr hohen Aufstiegen, bei denen infolge des stark 
arometerstandes und Partiardrucks des Sauerstoffes die Dissoziation 
Hb stiirker wird, mu6 die Sauerstoffversorgung des Kérpers Not leide 
‘gl. § 92 n. 95). 

Im Korper gelangt das Blut aus den Lungen, wo ein ziemlich holy 
artiardruck des Sauerstoffes herrscht (anniihernd derselbe wie in atm 
ohiirischer Luft), mit dem Blutkreislanf in die Capillaren der Korpe 
swebe, wo der Partiardrack des Sauerstoffes (der forigesetzt bei d¢ 
xydationen verbraucht wird) sehr niedrig, resp. = 0 ist; hier muB ah 
or Sauerstoff aus seiner Bindung an das Hb frei werden und kann ny 
a die Gewebe abgegeben werden (vgl. $91, innere Atmung). 

Schon unmittelbar nach der Entloornmg des Blutes findet in thm eine gerin 
-Zehrung statt. Nach liingerem Verwoilon unBorhath des Kreislanfes und bei héber 
tmperatnr kann sogar der Q ganz aus dem Biuto schwinden. Der Sanerstoffverbramch | 
sonders hoch bei jungen Erythrocyten, sowie bei den kernhaltigen Erythrooyten d 
igel (Morawits", Warburg"). Die Blutplittchen haben an der O-Zehrung einen 1 
ners starken Anteil: angeronnen erhaltenes Blot (x. B, durch Hiradingusatz) zeigt #1 
ol stirkere O-Zehrang als dafibriniertes (Onaka*®, Loeber'®), 

Wegen der yielfachen energischen Oxydationen, welche im lebend 
érper vor sich gehen, ist die Frage aufgeworfen worden, ob nicht etw 
ar O des Blutes in Form des Ozons (0s) vorhanden wire. Allein wed 
1 Blute selbst, noch auch in den aus demselben evakuierten Gasen i 
zon enthalten, 


Das Blut gibt gewisse Reaktionen, welche anf das Vorhandensein oxy dierend) 
srmente (Oxydasen ygl. 8.19) schlieBen lassen, Mischt man Blut (oder bluthaltl 
tinsigkeiton, x, 8, binthaltigen Harn) mit Guajactinktur und Wassorstoffsnperoxyd Hy) 
der verharatem Torpentinil, wolches stots Sanerstoff in Form eines organischen Peroxyd 
thilt), so tritt Blaufirbung ein. (Die in der Gaajactinktar enthaltene Gaajaconstio 
‘rd dabei oxydiert zn einer blan geflirbten Verbindung). Blut allein blint dio Guajactinkt 
ht; es enthilt duher keine dirckten Oxydasen |oder nur in geringen Mengen im d 
takocyten (Biwald*); Biter bliut Guajactinktur ohne weiteres). Dagegen blint Blut Ganjt 
tktur bei Gegenwart von H, 0, (oder altem Yerpentindl, s.0.); diese Wirkang ist ab 
cht auf ein Ferment (Peroxydase) eu bexichen, da sie durch Kochen nicht zerst 
rd, wahracheinlich spielt dabei der Risongehalt cine Rolle (r. Csyhlarz a. e, Birth? 
vdlich vormag Blat Wasserstoffsuperoxyd xu serlegen, os enthalt eine Katalase, die am 
iiert werden kann und dann nur die Wirkung der Katalasen zeigt, nicht etwa die d 
rekton Oxydasen oder Poroxydasen (Senter*), Rbenso ist dio Bhinung von Guajactinkt 
d Wasserstoffsuperoxyd durch Blut von dem Vorhandensein der Katalase durebass ums 
nygig (Liebermann'*, Lester**, Ewald”). — Katalase kommt in allen bishor untersuch) 
isehen tnd fast allen pflanzlichen Geweben vor (Battelli u. Stern™), Sie wird dun 
‘ypsin verdant, was fiir ihre Fiweifnatur spricht (Waentig u. Steche™), 


33, Kohlensiiure und Stickstoff im Blute. 


Il. Kohlensiiure — findet sich im venisen Blate durehschnittlic 
ind zu 50 Volumenprozent (Bohr u. Henriques*? fanden beim Hunde i 
‘ei Versuchen im Blute des rechten Herzens 48,5—51,5 Volumenprozent 
och ist der CO,-Gehalt des yenisen Blutes je nach dem Orte der Bluj 
itnahme und den Kreislaufsverhiltnissen sehr schwankend, im Erstick: 
nta am hichsten Der (O.-Gehalt dos artariallan Rintos ist netitel 


















(888) Avmensaure and Stickstolf im Blate, 


Volumeny wan. Der gesamte CO,-Gehalt im Blute betriigt noc 
einmal die Wilte yon der Menge, welche das Blut tiberhaupt anfaur 
imstande wire. 

‘Dio gesamte OO, des Blutes ist volistindig auspumpbar, anch die in F 
Monocarbonat vorhandene; sogar dem Binte kinstlich xugesetate Soda gibt dabei | 
ab (Pflager*), Ke mu8 demaach im Blate vino Snbstanz vorhanden sein, welche 
wie cine Sanre austreibt. 

Die Kohlensiiure findet sich im Blute: 

a) physikalisch absorbiert, nur zum geringsten Teil. Nach 
betriigt bei einem Dracke von 30 mm CO, die in 100 cm? Blut physi 
absorbierte Kohlenstiure nur 2 cm? (in der Flissigkeit der Blutkirp 
0,60, im Plasma 1,4 em®), 

b) Chemisch gebunden, der tiberwiegende Teil, Fir die che 
Bindung der Kohlensiiure des Blutes kommt nicht nur eine Substar 
das Hb fiir die Bindung des Sauerstoffes), sondern mehrere in Be 
Chemisch gebundene CO, findet sich: 

1. im Plasma. Das in der Blutfliissigkeit vorhandene Nat 
monocarbonat vermag mit CO, eine dissoziable Verbindung zu 
bonat einzugehen nach der Formel Na, CO, + CO, + H, O = 2 Na 
Beim Ansteigen der Kohlensiurespannung kénnen die Albuminal] 
der Blutiliissigkeit durch die Kohlensiiure zerlegt werden und so) 
Mengen von zuniichst Mono- und sodann Bicarbonat gebildet werden. 
dem gibt es aber wahrscheinlich auch dissoziable Verbindungen 2 
Eiweifstoffen und Kohlensiiure, tiber die jedoch niiheres nicht b 
ist (vgl. Bohr). 

2. in den Blutkérperchen. Das Hiimoglobin vermag auc 
Kohlensiture eine diseozialle Verbindung einzugehen; die Bindung d 
erfolgt dabei aber nicht an den gofurbten Bestandteil des H) 
bei der Bindung des O und des CO), sondern an das Globin (eben 
im Plasma Kohlensiiure an Eiweifstoffe gebunden ist, s. 0.). Auferd 
in den roten Blutkérperchen auch Kohlensiiure an Alkali als Bica 
gebunden, e 

Da die Kohlonsiure im Hamoglobin an sine anders Komponents gebunden » 
der Sauerstoff oder das Koblenoxyd, so wird die Kohlensiureverbindung nicht b 
durch gleichzeitige Sauerstoff- oder Koblenoxydanfoahme, ja nicht einmal durch 
wandiung des Himogtobins in Mot-Hb (Bohr), Dagogen beainlalt umgekebrt die A 
von Koblensiiure allordings die Sauerstoffverbindung (Bohr, Hasselbateh u, Krogh® 

Locwy" gibt fiber die Verteilung dor Koblensiinre im Blute folgende Obersi 

100com artoriellos Blut enthalten ca. 40ccm O0,. Davon sind: 


8) physSkalloch absorblort. . 4... sce ye ss 1,9een 
b) chemiseh gobanden 
1. im Plasma 
uls Biearbonat . . . . . ) . 12 com) 
arganisch gebunden) < s). tig} 28eem 
Qin den Blutkérperchem == tC 381 . 
als Bicarbonat. . . . . . » 68. } 14.3 
an Hiimoglobin 2 6 6 ee Te “aes 
40,0 cen 


Ill. Stickstoff — ist im Blute zu 1,2 (Bohr*), 1,04 (Buck 
u, Gardner**) Volumenprozenten vorhanden, und zwar der Hany 
nach physikaliseh absorbiert. 

Nach Bohr* ist dio Menge des Stickstoifs im Binto stots deatlich groBer 
Jonige, die Wasser unter denselben Verhaltnisson in sich aufnehmen wiirdo (0,9 Volumen 

Regnard a. Schloessing™ fanden im Vonenblate des Pfordes 0,U42 V 
prozent Argon. 


SS ~~ 


i Die Blutmenge. 


34. Die Blutmenge. 


Die Blutmenge des Erwachsenen betrligt '/,, des Ki ‘érpergewicht 
Bischoff), (nach Haldane u. Smith** [siehe unten] nur 1/s95), — bei 
eugeborenen ¥/;) (Welcker). 


Nach Sehiicking!* soll joloch dor Rlnigohalt dos sotort abgonabelten Kind 
\"g der des spiter abgenabelten sogar =", des Kirpergewichtes botragen. 


Zur Bestimmung der Blatmenge dient; 


1, Mothode von Weleker™ (vgl. Fr. Miiller*), — Man fingt ans einer geatac| 
wrotia mit eingebundener Kanfile das Blut in siner gemossenen Menge einer 
mmoninmoxalat auf, um die Gerinnang zu verhiten, Schon withrend des Entbintens i 
fn in sino Vene ontsprechende Mengen einer 0,9"), warmen Kochsalzlisung 
o Hers und Atomtiitigkeit moglichst lange zn erhalten, oventuell wird kitnatliche Atma 
ngeleitet. Steht das Herz still, so bindet man in die beiden Raden der durehschnitten 
wrotis cine fJaeformigo Kanile cin und M8t cine 0,9 Kochsalzlisnng unter ein 
ruck von ctwa 1m Wasser ¢infliefon, wihrend man any den durchschnittenen Wen 
gulares und dor Caya inferior diese Spllfliissigkeit so lango sammolt, bis sie wass 
ar ablinft. Hierauf wird der gesamto Kérper xorhackt und (mit Ausnahme des j 
ogenen Magen- tind Darminbaltes, dexsen Gewicht man vom Kérpergewicht abzieht) 1 
asset ansgelangt und nach 24 Standen ausgepreft. Dieses Wasser and die Kochi 
issigkeit werden vermischt und gemessen. Man bestimmt schlieBlich nach einer der im 
igegebenen Methodon in dem Blut und den Extrakten den Hiimoglobingehalt und berechy 
mach die gesamte Blutmenge. 

Man fand das Gewicht des Blutes von Muusen = 1/;,—1/,,, — ¥ 
feerschweinchen = "yy (/,y—"/as), — von Kaninchen = 1/s5, (Ys? 
2), — von Hunden = 1/;5 (4/,;—*/14), — von Katzen = '/s45, — W 
égeln = */,,—1/,3, — von Frischen = 1/,,—'/4), — von Bi 
\u—"/1» des Kérpergewichtes (ohne Magen- und Darminhalt). 

2 Beim lebenden Tiere lieBen Gréhant u. Quinquand® vine gemeasene Monge | 
oatmen, entzogen dann ein Blutqnantam und bestimmten darin den CO-Gehalt. Hier 
‘gibt sich leicht dig Blutmengs. Nach demselben Prinzip bestimmten Haldane 1. Savill 
6 Blutmenge des Menschen; sie fanden dieselbs = '/,,., des Kérpergewichtes. Dowgla) 
vstimmte nach derselben Methode die Blutmenge des Kaninchens (in Kubikzentimet 
wogen auf das Brattogewicht) zn '/,~ beim mannlichen ‘Yer, beim weiblieben "Ti 

Obor Versncho der Bestimmung der Blutmengo nach anderen Methoden vel. Nelson 
hitrer**, Abderhalden ua. Schmid**. 

Im Hungerzustande nimmt die Blutmenge ab, doch stimmen d 
‘ntersucher nicht darin iberein, ob diese Abnahme proportional de 

at dat erfolgt oder nicht. Fette Individuen sind relativ blutiirme 

Blutverlusten ersetzt sich leichter die Menge durch Wasser, e 
hashish regenerieren sich die Blutkérperchen (vgl. § 35). 

5. Die Bestimmung der Blutmenge einzelner Organe — g 
zhieht nach pipes cee Abschnttrung ihrer Adern intra vitam. Man lau 
us dem zerkleinerten Organ das Blut aus und bestimmt den Bla 
urch Vergleichung mit einer zu yerdtinnenden Blutprobe (Ranke#*), - 
Die Bestimmang nach dem Tode im gefrorenen Zustande ist zu verwerfer 

J. Rankes* bestimmte so am lebenden ruhenden Kaninchen die Ve 
vilung des Blutes; es fand sich yon der gesamten Blautmasse je * 
=a) in den ruhenden Muskeln, — b) in der Leber, — ¢) in den Krei 
imfsorganen (Herz und grofe Adersttimme), — d) in allen tibrigen Organi 
usammen (in den Lungen sind 6,85°/, des Gesamtblutes, Menicanti# 

Den hervorragendsten Einflu6 auf den Blatgehalt der Organe hat d 
‘atigkeit derselben; hier gilt der alte Satz .ubi irritatio, ibi afflaxus 


(dtenlala Rataen din Gnatshaldettoan Ane Maman ain Manns 

















(835) Pathologisehe Vermehrung oder Vermindérung Ger Ethdnonee, 


ar 47%/, aunehmen- Wihrend einer gesteigerten ‘isigkeit de 
Ona xe vielfach die anderen: bei der Verdai herrscht | 
intidigkeit und geistige Abspannung; — bei starker Mi ve 


sich die Verdauung; — bei starker Absonderung der geréteten H 
die Titigkeit der Nieren herabgesetzt, 


35. Pathologische Vermehrung oder Verminderun; 
der Blutmenge. 


1. Kine Vermohrung der gesamten Blutmenge wird als Plethora be 
Ex ist aweifelhaft, ob eine Plethora iiberhaupt vorkommt; doch kann die Méglicl 
besonders kriftige Individuen bei fiberreichlicher Ernihrang nicht bezweifalt werde 

Kinstlich kann Plethora durch Einspritsung von Blat derselben Ari 
gerufen werden, Wird die normale Blutmenge bis zu $3", vermehrt, so tritt noch 
normer Zustand ein, namentlich wird der Blutdruck nicht danernd erboht, Es ni 
Blut yornebmlich in den sehr gedehnaton Capillaren Platz, die hierbei fiber ihre 
Blastizitat hinans gedehnt werden (Worm-Maller*), Kine Vermehrang der Blutmeng 
bis zn 150°), goflihrdet unter betriichtlichon Blutdrnckschwankungen direkt da 
(Worm-Maller®). Von dem cingospritzten Blute nimmt schnoll dio Lymphbildung 
wird das Serum schon in 1—2 Tagen verarbeitet, das Wasser vorwiogend durch ¢ 
ansgeschisden, da Biweif+znm Teil in Harnstoff umgesetzt (Landois). Daher ersel 
diese Zeit das Blut relativ reicher an roten Blatkirperchen (Punum", Lesser™ 
Miller), Die roten Blntkirperchen zerfallen viel langsamer, and das yon ihnen | 
Material wird toils xu Harnstoff, tells xa Gallenfarbstom (nicht konstant) verarbeitet 
hin kann jedoch noch big zu 1 Monat ein Oberschuf an erhaltenen roten Blatké 
beobachtet werden (Tachiriew™). Da in der Tat die Blutkirperchen langsas 
woehsel zorfullen, geht darans hervor, da die Harnstoffbildang grifer ist, wonn 
die gleiche Menge Blut fri8t, als wenn ihm dio gleiche Menge transfundiort wird (70. 
Forster, Landois). In lotzterem Fulle hilt oft tagclang cine miiGigo Steigerung ¢ 
stoffes an ale Zeichen eines langsamen Zerfalles der roten Blntkiirperchen (Worm-. 
Landois), 

2. Vorminderang dor Blutmagse im ganzen (Oligaomia vera) — ¢t 
jedou direkten Blutvertuste auf, Neugeborenen kann schon ein Blutverlust von einige 
zentimotern, einjiihrigon Kindern cin solcher yon 250 em*, Erwachsonen der Verlust d 
Bintmonge lebensgefihrlich werden. Frauen tiberstchen leichter selbst erhoblicho Blu 
als Minner; bei ihnen scheint schon wegen der periodischen Erseteung des verloren, 
in jeder Menstroation die Blatnenbildung leichter und schneller su erfolgon. Fette 1 
ferner Greise und Schwichlinge sind gegen Blutverluste woniger widerstandst 
schneller die Blutung erfolgt, desto gefahrlicher ist sie, Allgemeine Bliisse n 
dor Hantdockon, angstigende Beklommenhoit, Erschlaifang, Flimmern yor den Auger 
xausen und Schwindel, Erloschen der Stimme und Ohamachtsanwandlangen pilegen 
Biutverluste xa begleiten, Atemnot [— und scbnoller atmond hancht er mit pr 
Strom das Leben aus (Sophokles’ Antigone) —], Stocken der Drlsonsekretionen, 
wnGtlosigkeit, sodann Erweiterung der Pupillon, unwillkiirlichor Harn- und Kotab; 
schlieBlich allgomeine Konvulsionen sind die sicheron Vorseichen dos Verblntung 
Bis zu '/, dor normalen Blutmengo kann Ticron entzogen worden, ohne daB der 1 
in den Arterien dauernd sinkt, weil diese durch Contraction sich dem kleiner 
yolumen anpassen (infolge der animisehen Reizung des yasomotorischen Centrams 
dulla oblongata). Blutverlast bis */, der Blatmenge setzt den Blutdruck erheblic 
Hunde erholen sich nach Kotleerung von '/, der Blutmenge; wurde "/, entaommen, 
dio cine Halfte dor ‘ero, die andere erholte sich ebenfalls spontan (Mayd!", Fei 

Fibrt die Blotung nicht xam Tode, so erfolgt sehr bald ein Obertritt yon 
Afissigkoit in das Bint, Dor RiwolSgehalt des Blotes ist zuntichst vermindert, dab 
das Albumin weniger ab als das Globulin. Nuch 1—2Tagen jedoch nimmt das 
zu, wihrend das Albumin weiter abnimmt, infolge der Globulinxunahmo steigt sch¢ 
ersten Tugen der EiweiBgehalt auf seinen urspriinglichen Wert und hiher. Die Rog 
der roten Blutkérperchen beginnt schon sehr bald nach dem Blatyerlust (dabc 
kernhaltige Blutkirperchen in der Blutbubn beobachtet; Koeppe*’, Zenoni*?) 
schon am 2, Tage an der zunebmenden Zab) 2n erkennen, Vollstindige Regenora 
bei Blntvarlusten, die eine anfingliche Abnahme der Blatkorperchenzabl am 30— 
Folge hatten, in 16—20 Tagen erreieht; wiedorholte Aderlisse scheinen die Nenb, 
beschloanigen (Aderliisse bel Chlorose, Aniimie!). Die neven Tutkirperchen haben 


Landols-Rosemann, Physiologie. 14. Aufl. 





Literatur (§ 80—35). 





L stirker ab, als dio Erythrocyton; Zion um folgenden ‘Tage Witt aber e 
ime, meist Gber die urspriingliche Zahl hinaus ein (Otto, Inagaki). — Nach groth 
ttverlasten tritt cine Steigerung des Energieumsatzes, sowie eine Retention yon N a) 
Ausdruck der Blutregeneration (Fuchs, Hdri™), 


Literatur (§ 30—85). 


1. LW. Winkler: B. d. ch. G, 24, 1891, 3602. %. phk. Ch. $18 1892, 171. — 2. Ch. Boh 
edemanns Ann. d. Phys. 0. Chom. N. F. 68, 1899, 500. — 3. Ch. Bohr u, J. Bock: Wiedemam 
oalen d. Phys. u. Chom. N. F. 44, 1891, 318. — 4. Ch. Bohr: 8. 4.17, 1905, 104. - 
Ch. Bohr: W. Nagel Handbuch der Physiologie, Braunschweig 1909, 1, 60. — 6. J. Ha 
ve: J.0.P. 22, 1898, 298. 25, 1900, 295. — 7. F. Maller: P.A. 108, 1904, 54t. - 
J. Barcroft: BP. 7, 1908, 711. J. Bareroft u. P, Moravits: D.A. kM. 98, 1908, 22 
Pflager: Om, W. 1867, 724. — 10, EB. Piliger: P.A.1, 1868, 70, — 11. Seselkon 
» 45, 2. Abt, 1862, 171. — 12. L, Meyer: Zr. MN. 8, 1857, 256, — 13, @. Hiifne: 
894, 130, 1903, 217. — 14. G. Hiifner: A, P. 1901, Suppl, 187. — 15. A, Lee 
P. 1904, 231, — 16. P. Morawitz: A. P. P.60, 1909, 298, — 1%, 0. Warburg: % ph. 0) 

1909, 112, — 18. M. Onaka: % ph. Ch. 71, 1911, 193, — 19, J. Locher: P. A. 14 
1, 281. — 20. W. Kwald: P. A. 116, 1907, 3384. — 21. EF. v. Coyhlarz n. 0.0. FRrth 
B.10, 1907, 358. — 22. G. Senter: %. phk. Ch. 44, 1903, 257. S51, 1905, G73. - 

L, Liebermann: P. A. 104, 1904, 207 un. 227. 108, 1905, 489. — 24. B.S. Lesser 
8.49, 1907, 571. — 25. F Battelli u. 1. Stern: B. P. 10, 1910, 531. — 26, P. Waentig ) 
Steche: %. ph. Ob. 83, 1913, — 27. Bohr vu. Henriques: A. dP. 1897, 2B. = 
Ch. Bohr: Handbuch d. Physiologie v. W. Nagel, Braunschweig 1905, 1, 83, — 29, 
or die Kohlensiure des Blutes, Bonn 1864. — 30. Ch. Bohr: Handbuch der i 
W. Nagel, Braunschweig 1905, 1, 107. — 31. Ch, Bohr: 0, P, 4, 1890, 253. 5. A. B, 11 
8, 1895, 363. Die Kohlonoxydintoxikation, Kopenhagen 189), pag. 5), — 82, Gh. Zoh) 
Hasselbatch u. A. Krogh: 0. P. 17, 1904, G61. 8. A. 16, 1904, 402. — 33. AL 
Gase des Kérpers, in C. Oppenheimers Handbuch der Biochemie, Jena 1911, EV, 4, 
34. Ch, Bohr: Handbuch der Physiologie v. W. Nagel, Braunschweig oe 1, 117. - 



























G. A. Buckmaster 1. JA. Gardner: 3.0. P.48, 1912, 401, — 36. PR a. 2) 
Hoesing: O, r. 124, 1897, 302. — 8° cree Zeitechrift f. wiss. Zoolog. 1856, 33) 
(857, 65. — 38. J. Haldane a. J.D. Seni P. 26, 1900, 331. N. Zante tod 








% 11, 1908, 34. H, Welcker , 1858, 145. P. 
M4, 63. — 40, A. Seheking: Bk, W. 1 
Gréhant u. E, Quinquaud : 0x. 94, 1882, 1450. J.d.P. 18, 1 
|. P. 83, 1906, 493. — 44. L. Nelson: AP. P. 60, 1909, 340. — 45. J. Sehirer: A. P.} 
1911, 171. — 46. E. Abderhalden m. J. 2%. ph. Ch, 66, 1910, 120. —~ 47. Rawky 
Blutvorteilung und der ‘Nitigkeitswechsel d. Organe. Leipzig 1871. — 48. G. Menieant 
3. 80, 1894, 439. — 49. Worm-Miller: L. B. 25, 1873, 573. Transfusion und Plethor 
jotinala 1875. — 60. Panum: V.A. 29, 1864, 241. — 1. b. Lesser: L. B. 26, 187) 
b — 52, 8, Techiriew: L. B. 26, 1874, 58. J. Forster: 7B. 11, 1875, 496. > 
Maydl: Wiener med, Jahrb. 1884, 61. — 55. Feis: V. A, (18), 8, 1895, 73. — 56. Ke 
m. W. 1892, 904, . i: V. A. 189, 1895. — 68. J. G, Otto: P, A. 36, 1 

59. Inagaki: %, 8.49, 1907, 77. — 60, D. Fuchs: P. A, 130, 1909, 156. + 
Pz thivis B.-A. 180, 1908, 177. 





+ 11, Jabre., — 
2 ALP. 1901, 
2, 564. is C0 oma 

















Physiologie des Kreislaufes. 





36. Ursache, Bedeutung und Einteilung. 


Das Blut befindet sich innerhalb des Gefiiisystems in ununterl, 
kreisender Bewegung, die von den Herzkammern aus durch die A 
A. pulmonalis, darch deren gesamte Verzweigungen, durch das 
der Capillargefiibe und auf dem Wege der Venen zu den Vorkam: 
Herzens zuriickflihrt (William Harvey, 1628). 

Die Ursache dieser Kreislaufbewegung ist die Dr 
ferenz, unter welcher das Blut in der Aorta und A. pulmonalis \ 
und in den beiden Hohlyenen und in den yier Lungenyenen ar 
steht. Denn die Blutfltissigkeit strimt natiirlich ununterbrochen 1 
jenigen Gegend des geschlossenen Réhrensystems, in welcher der 1 
Druck herrscht. Je gréfer diese Druckdifferenz, um so lebhafte) 
Strombewegung; Aufhiren dieser Differenz muB (wie nach de 
die Strémung erlischen lassen. 

Die Bedeutung des Kreislaufes ist eine doppelte: den Gew 
Kirpers werden durch das Blut die fir das Leben notwendigen £ 
geftihrt, — andrerseits werden die Umsatzstoffe mit dem Blute 
Geweben abgeleitet und den Absonderungsorganen tibermittelt, 

Der Kreislauf des Blutes wird eingeteilt: 

1. In den grofen Kreislauf, — umfassend die Bahn yo 
Vorhot, linken Ventrikel durch die Aorta und ihre Aste, die Kir 
laren und Venen, bis zur Einmtindung der zwei Hohlvenen in der 
Vorhof. 

2. In den kleinen Kreislauf, — umfassend die Bahn det 
Vorhofs und der rechten Kammer, der Pulmonalarterie, der Lun, 
laren und der yier Lungenyenen, bis zur Einmtindung derselber 
linken Vorhof. 

3. Der Pfortader-Kreislauf — wird mitunter als besonder 
laufsystem bezeichnet, obgleich er nur eine zweite, in eine Venenl 
gefligte Capillarauflisung darstellt. Er wird gebildet yon der aus 
geweidevenen (V. gastrica superior, V. mesenterica superior et inf 
Y. spleniea) sich zusammenfiigenden Vena portarum, die sich i 
der Leber zu Capillaren auflist; diese fithren in die Venae he 
und schlieBlich in die untere Hohlvene. 


Abnliche Verhiiltnisse finden sich bei manchen Tioren noch an anderen St 
besitzen die Schlangen ein derartiges System in der Nebenniere, die Frische in 


) Das Hers. Anatomisches, ' a 


37. Das Herz. Anatomisches. 
Anordnung der Muskelfasern. 


Die Wandung des Herzens setzt sich (wie die der grofen GefiiBe, $49 
s drei Schichten zusammen, yon denen die mittlere bei weitem ay 
irksten entwickelt ist: dem Endokardium, 
yokardium und Epikardium. Pig. tt 
Das Endokardium ist eine bindegewebige Hant, k 

foine elastische Fasern (in den Vorhifen stirker 

in Kammern entwickelt, selbst gofonsterte Mem- 
nen bildend) und glatte Muskelfasern entbalt. Der 
rzbible xagewandt liegt ¢in vinschichtiges Kadothel 
Yeonaler, platter, kernhaltiger Zellen, 

Das Myokardinm besteht ans einem Notz quer 
stroifter Muskelfasern, die sich aber von den qner- 
itreiften Muskelfasern der Skelettmuskeln durch die fol- 
iden Kigentimtichkeiten unterschoiden. Die Herzmuskel- 
erm haben kein Sarkolemmua. Der Kern ist central 
egen, nicht an der Peripherie, wie bei den Skelettmuskeln. 
+ einzelnen Muskelfasern des Herzens stehen darch Aus- 
fer in netzartiger Verbindung untereinunder; sie 
den cin xusammenhingendes .Syneytinm™. (Die Boden- 
ug dor sogenannten ,Querlinien" der Heramuskeltasern, die 
her als Zellgrenzen aufgefalt wurden, ist noch zwelfethaft,) 

Das Epikardinm ist das viscorale Blatt des Peri- 
rds (Herzbeutols), os ist cine bindegewebize, mit feinen 
stischen Fasern durchsetate Haut, die anf der freien Fiche 

einfachos Lager unregelmilig-polygonaler, platter Endo- 
en triigt. 

Die Hauptmasse der Muskulatur des Herzens 
mt der mechanischen Leistung des Herzens: 
r Fortbewegung des Blutes. Diese Muskelfasern 
id an den Vorhéfen and den Kammern nach Art 
1s Hohlmuskels angeordnet, so dab bei der 
traction der Innenraum yerkleinert, resp. auf 
n Inhalt ein Druck ausgetibt wird. Im einzelnen 
. die Anordnung der Muskelfasern allerdings 
hr verwickelt, da die verschiedenen Ziige viel- 
ch miteinander yerbanden sind und aus ihrer {ne "Staue" 5 Zetcnat 
Sprtinglichen Richtung in andere Richtungen 
vergehen. — Daneben existiert aber im Herzer 
ch ein besonderes, in seiner Bedeutung erst in 
uerer Zeit erkanntes spezifisches Muskel- ¥ 
‘stem, das der Reizerzengung und Reiz- 
itung ($45) dient, es wird als Reizleitungs- } 
stem bezcichnet. Die Muskelfasern dieses 
stems sind durch ihr histologisches Verhalten 
m der thrigen Herzmuskulatur unterschieden; sie verlaufen in bestimmte 
thnen und sind in ihrem Verlauf yon der tibrigen Herzmuskulatur dare 
ndegewebige Scheiden getrennt, erst an ihrem Ende treten sie mit de 
wigen Herzmuskulatur in Verbindung. 


1. Die Muskulatur der Vorhéfe hat im allgemeinen eine Anordnun 
zwei Schichten: cine diufere transyersale, die sich kontinnierlic 
yer beide Vorhéfe fort erstreckt, und cine innere longitudinale. Dj 





Schema dos Kreistautos. 





($87) Vie Moskulatar des Hersens. 


tinBeren Fasern lassen Sich von den einméindenden Venenstimmen 
die yordere und bhintere Wand hin verfolgen. Die inneren Fat 
besonders dort reichlich hervortretend, wo sie sich senkrecht an d 
ringe ansetzen, doch sind sie namentlich in der vorderen Wand 
hife an einzelnen Stellen nicht kontinuierlich angeordnet. 

An dom Septum der Vorhife ist besonders der ringformige Mus 
horvortretond, welcher dio Fossa ovalis (die frihere embryonale Offnung de 
ovale) umgibt, An den Einmiindungsstellon dor Venen finden sich 
Faseralige: am wenigsten ausgupriigt an der Vena cava inferior, stark und bis 
anfwiirts reichend an der Vena cava superior. An den Einmiindungen der vier Li 
erstrecken sich bei cinigen Siingern quergestreifte Muskelfasern anf dio Langeave 
den Hilus der Lungen mit inneren Ring- und anSeren Liingsfasern, bei anderen ( 
sogar bis in die Lungen hinein. Anch an der Einmfindungsstolle der Vena ma 
und in der sic schlicBenden Valvula Thebesii finden sich Muskelfasern, zum: 
— Im Perimysiam der Vorkammern finden sich viele elastische Fasern. 

2. Die Muskulatur der Kammern. — Man trifft unter dem Per 
zuerst eine iubere longitudinale Schicht. welche am rechten 
nur einzelne Biindel, am linken jedoch eine zasammenhiingende } 
fabt von etwa '/, der Gesamtdicke der Wandung. Eine zweite 
longitudinaler Fasern liegt auf der Innenfliche der Kamp 
sie namentlich an den Ostien, sowie innerhalb der senkrecht aufs 
Papillarmuskeln deutlich sind, wihrend sie an den anderen Stell 
die unregelmabig verlanfenden Ztige der Trabeculae carneae ersetz| 
Zwischen diesen beiden Liingsschichten liegt die michtig 
Schicht der transversal geordneten Ziige, welche in eimzelne 
ringférmige Blindel zerlegbar ist. In der linken Kammer lift s 
Schicht in Gestalt eines geschlossenen Muskelringes heransschi 
hesteht teilweise aus Fasern, die tberhaupt nicht sehnig enden, 
stets muskulis bleibend ringfirmig in sich zurlick verlaufen (Are) 
drei Schichten sind jedoch nicht vyOllig selbstundig und vor 
abgeschlossen, vielmehr vermitteln schrag verlaufende Faserztige 
mithlichen Ubergang zwischen den transyersalen Blittern und dey 
und ainBeren longitudinalen Ziigen. 

An der Spitze des linken Ventrikels biegen iiufere liingsve 
Fasern, indem sie in den sogenannten Wirbel zusammentreten 
Innere der Muskelsubstanz cin- und aufwiirts und gelangen in die 
muskeln; doch sind keineswegs siimtliche in die Papillarmush 
steigende Ziige von diesen vertikalen Muskelbiindeln der dinfieren O 
abzuleiten; viele entstehen aus der Ventrikelwand  selbstiindi 
Albrecht® kann man in dem Spitzenteil des linken Ventrikels ein fi 
Muskelsystem nachweisen, welches einen tiberwiegenden Teil 
samten Wanddicke dieses Absehnittes einnimmt, von der Herzspitz 
Kuppe der Papillarmuskeln reicht und zu diesen in engster 
steht; die eigentlichen Papillarmuskeln und dieses Muske 
bilden danach eine anatomische Kinheit, die Papillarmusk 
nichts als die freien mit den Chordae als Sehnen in Verbindung 
Enden dieses Systems, 


3. Das Reizleitungssystem*. — Die spezifischen Muski 
dieses Systems unterscheiden sich von der iibrigen Herzmuskulat 
logisch dureh das Pritvalieren des Sarkoplasmas und das Zurtickt 
Fibrillen, augerdem auch noch durch ihren Reichtam an Glykog 
System enthiilt auber diesen spezifischen Muskelfasern aber auch z 
Nervenfasern und Ganglienzellen (Hngel*, Morison®), Ma 





2 Dus Roizloitangssystem. Die Klappon dos Herzens. a 


heidet zwei Abschnitte: das atrio-ventrikul&re und das sino-aurik) 
re System. 5 

a) Das atrio-ventrikulire System, — Die Muskulatur der Vo 
mmern ist von der der Kammern durch bindegewebige Ringe, d 
anuli fibrosi, getrennt. Diese Trennung ist aber keine vollstandigi 

zieht ein Muskelbtindel, das nach seinem Entdecker genannte Hit 
trioventrikular-Biindel, vom Vorhof zu den Ventrikeln. Nach de 
itersuchungen yon Tawara? bildet dieses Btindel oberhalb des Septum 
rosum atrioventriculare einen kompliziert gebauten Knoten, 

er Atrioventrikularknoten, durchbricht das Septum und liuft in zw 
trennten Schenkeln an der Kammerscheidewand herab, durchsetat dj 
intrikelhohiriume in Form yon Trabekeln oder falschen Sehnenfuide 
d tritt endlich an den Papillarmuskeln und den peripheren Wandsehichte 
t der Kammermuskulatur in Gestalt der Purkinjeschen Viiden in Ver 
idung. Dieses Verbindungssystem samt seinen Endausbreitungen zeig 
im Menschen und allen untersuchten Tieren eine gesetzmiihige, im 

d ganzen iibereinstimmende Anordnung. Das Biindel ist auf seinet 
nzen Verlaufe von der tibrigen Herzmuskulatur stets durch 

webe getrennt, erst in seinen Endausbreitungen verschmilzt es mit de 
wohnlichen Kammermuskolatar. 

Als Purkinjescho Biden worden seit ihrer Beschreibung durch Purkinje (1845) Nets 
wer gallertartiger Faden von eigenartiger histologischer Straktur (rohrenfirmige Gebild 
t ganz von Sarkoplasma erfillt, mit nur wenigen randstindigen Langefibrillen) bexeichne 

an der Innenfliiche der Herzkammer besonders beim Schafe sich finden. Erst spite 
rden sie als die letzten Ausliufer der Schenkel des Hisschen Bindels erkannt. 

b) Das sino-aurikulire (sino-atriale) System. — Kine dem 74 
traschen Knoten ganz analoge Bildung liegt nach Keith u. Flack® a 
r Grenze zwischen Vena cava sup. und rechtem Vorhof: Keith-Flack 
her oder Sinusknoten. Von dem Knoten verlaufen Verbindungsfaser 
t Muskulatur des Vorhofs und der Vene. 

Hntwicklungsgeschichtlich sind die cinzelnen Abschnitte des Herzens zanich) 

sch breite Chergiinge der Muskolatur dex einen Abschnitts in die des andarn ¥% 
‘tor findat eine Reduktion dieser Verbindangen zu schmilloren Briicken statt. Bek de 
chon geht noch die Muskalatur das Vorhofs im ganzen Umkreis der Vorhofskammergrent 
die Muskulatur der Kammor tber, bei den hihoron Wirboltieren werden dann die Ve) 
dungen anf bestimmte isolierte Bindel beschriinkt. — Bei den Amphibien und Reptilie 
fteht auch noch eine besondere Verbindung vom Ventrikel zam Bulbus aortas, der hie 
en selbstiindigen Herzabschnitt darstellt (Kd/be*, vgl. Mangold ®), 

Die Klappen des Herzens — die arteriellen (Semilunarklappen 
d die yvenésen (Zipfelklappen: Mitralis und 'Tricuspidalis) bestehen au 
rillirem Bindegewebe mit clastischen Fasern und werden vom Endokar 
erzogen. Die Zipfelklappen besitzen noch quergestreifte, radiir ver 
ifende Muskelfasern, die yon der Muskulatur der Vorhéfe ausgeher 
ich Albyecht® ist diese Klappenmuskulatur absolut konstant und stell 
te ganz unmittelbare Fortsetzung der innersten longitudinalen wie de 
rauf nach auben folgenden transversalen Schiecht der Vorhofsmuskalaty 
r. Nach ibrem Eintritt in die Klappe ordnen sich die Muskelfasern 7 
twelnen getrennten Bitndeln, welche ihren Ansatz ausschlieblich an de 
ordae tendineae finden, und zwar fast nur an denen, welehe direkt an 
theftungsrande der Klappe inserieren und mit einem Anteile an dere 
terer Fiiiche zur Ventrikelwand verlaufen. 

Unterhalb der Semilunarklappen der Aorta und Pulmonalis befinde 
ch Muskelfasern, welche bei der Contraction des Ventrikels in Form yor 





1838, Ernithrung und tsolierung des Herzens. 


Muskelwiilsten ans der Wand ae auf denen die Tascher 
mit ihren tiefsten Teilen aufsitzen ( a, vgl. aeiesnorsi 
Gewichts- und Mabverhiiltnisse des Herzens. Dor ausschlaggebende | 

dio HorzgroQo ist das Kérpergewicht und die Entwicklung der Muskulatur ( 
Es kommen nach W. Maller" beim Kinde und ee Dia nam ESrpere FI 
at by. Klepesmeret 5 f Hacesabattins — baa ner ee 

4g Heenan bei 100kg 3,59; div Vorbife werden mit xunehmeniem Alte 
Der rechte Vontrikel hat das halbe Gewicht des linken, — Dicke des linken Ventril 
Mitte beim Manne 114 mem, beim Weibe 10,15 mm; — Dieko des rechten 4,1 und 


38. Erniihrung und Isolierung des Herzens. 


Das ausgeschnittene Herz schligt noch eine Weile fort (C 
300 v. Chr.): bei Kaltbliitern linger, selbst Tage hindurch, bei 
blittern sehr viel kitrzer. Zuerst wird die Kammeraktion’ ges 
sodann folgt nicht jeder Vorhofscontraction eine Kammersystole , 
auf zwei oder mehrere Vorhofscontractionen folgt nur eine sch 
Ventrikelcontraction. Dann ruhen die Kammern vyollig, our die 
schlagen noch schwiicher weiter: doch ruft eine direkte Kammer 
etwa ein Stich, eine Systole derselben hervor. Im weiteren Verla 
dann der linke Vorhof: der rechte schliigt noch weiter (das ,U 
moriens* der Alten). Nach Aufhéren der Vorhofscontractionen 
noch die einmiindenden Venen ganz schwach pulsieren; stehen die Pt 
venen still, so kinnen noch die Hohlvenen lange Zeit weiter : 
(niemals umgekehrt) (Hering ™). 

Die Ursache fiir a Aufhiren der Tiitigkeit des Herzens na 
Ausschneiden liegt in der Stérang der normalen Erniihru 
Herzens; wie jedes Organ, kann das Herz seine Titigkeit auf di 
nur bei normaler Erniihrang fortsetzen. Beim Kaltbliiter-(Frosch- 
erfolgt die Erniihrang direkt aus dem in den Herzhéhlen bet: 
Blute, es kann daher auch nach dem Aussehneiden noch geraume | 
dem im Momente des Ausschneidens in den Héhlen vorhandenen BI 
sorgt werden. Beim Warmbliiterherzen findet dagegen die Ernihr 
Herzens durch eigene Blutgefiife statt: die Kranzgefiibe, Aa. ¢ 
riae cordis, welche aus den Sinus Valsalvae der Aorta entsprin, 

Nach Bracke! sollten die Somilnnarklappen bel der Systole die Ursprangs 
der Coronararterien so verlogen, daB diose nicht systolisch, sondern erst bei der | 
des Ventrikels goflllt wiirden. Briicke stellte sich yor, dal die Filllung der Ventri 
die Muskelaiige der Ventrikelwand dehnon und somit dio Kammerhéhle erweiter 
dieser Vorgang wiirde, wenn er systoliseh erfolgte, der Herztitigkeit entgogenarh 
der Diastole dagegen dieselbe unterstiiteen. In diesem Sinne sprach Brileke 5 
sSelbststonerung des Herzons", Diese Vorstellung ist aber nicht nt 
(Hyrtt): dio Semilunarklappen legen sich bei der Systole niemals dicht an die 
Aorta an, os bleibt vielmehr zwischen Klappe und Wand stots ein blutgaffiliter Rat 
dor Puls der CoronargefiiGe ist daher synehronisch mit dom der Art, pulmons 
angesehaittane Coronarurterie spritet kontinnierlich mit systolischer Verstirkang 
Arterien. 

Die Capillargefi®e des Myokards sind entsprechond der onergischen 
des Herzens sehr reichlich; sie liegen innerhalb der Muskelbfindel den Muskelzolle 
Die Venen sind mit Klappen ansgestattet. Diese bringen es mit sich, da bei 
traction der Ventrikel das Bint in den Herzvenen iihnlich beschleunigt wird w: 
Venen der Muskeln. Zugleich werden aber im Boginn winer jeden Systola die a 
GofiBe erwoitort; so wird durch die ‘Titigkolt des Herzens die Blntversorgang 
gobessort. Damit steigt aber wiederum die Kraft der Horatitigkeit (Langendor, 
Uber die Vasomotoren und -Dilatatoron der Kranzgofafe vgl. $46, 

Die normale Tiitigkeit des Warmbltiterherzens ist an die Io 
der Bluteirculation in den Kranzgefiiben gebunden. Wird die Bly 








[$38] bre—ung und Isolierang des Herzens, 


miBigen Schlagon bringeM. Auch beim menschlichen Herzen 
miglich; Kuliabko™ konnte ittene Herzen von mens 
Leichen 20 Stunden nach dem Tode zum Pulsieren bringen; das I 
beitete dabei ziemlich regelmiBig tiber eine Stunde lang. 

Am ausgeschnittenen Herzen kann die Frage ‘imentell 
werden, von welchen Bedingungen die Fortdauer normal¢ 
tiitigkeit abhiingt. 

A. Die Zusammensetzung der Niéhrfliissigkeit, die du 
Herz strimt. 5 

1. Die Fitissigkeit muB isotoniseh sein (vgl. § 15), um ni 
Herzmuskel direkt zu schiidigen. Man vei let daher im allg 
cine isotonische Kochsalzlésung (0.8—0,9°/,). Diese vermag jedoc 
fir sich die Tuitigkeit des Herzens nicht zu unterhalten: die K 
Herzsehliige nimmt dabei fortwiihrend ab bis zum villigen Stillsts 
derartiges, durch Kochsalzlisung ,erschipftes* Herz ae jedoc 
eine geeignete Nihrfliissigkeit wieder zum Schlagen gebracht wer 

2. Die Fitissigkeit maf aufer Na Cl als notwendige anorga 
Salze enthalten: Ca Cl, (Langendorff u. Hueck*), K Cl (vgl. unter 
wahrscheinlich auch Na H COs. 

3. Dem Herzen mu Sauerstoff zugeftihrt werden, wenn | 
volle Leistungsfihigkeit hewahren soll (entweder durch die Fi 
oder durch Einschliefung des Herzens in eine Sauerstoffatmosph 
hohem Druck; Porter ®*), Allerdings vermag kurze Zeit lang das 
bltiterherz mit sehr geringen O-Mengen auszukommen, das des Ka 
sogar ohne Sauerstoff, 

4, Das Herz kann obne Zufubr organischer Nihrstoffe ; 
indem es yon seiner eigenen Substanz zehrt (Rohde**), Doch gen 
nicht auf die Dauer: es mué dann flir Ersatz ret werden. { 
ist hierftir z.B. Serumalbumin, Traubenzucker, Galaktose, aber nicl 
lose sowie die Disaccharide: Rohrzucker, Maltose, Lactose (Locke 
kirch uw. Rona**). Das Herz verbraucht unter anntihernd physiol 
Verhiiltnissen ungefiihr 4 mg (Knowlton u. Starling), 2,.2—3.4 mg 
Jeld®) Traubenzucker pro Stunde und pro Gramm Herzmuskel. 

5. Die Ernihrungsfliissigkeit mu zugleich die bei der Herz 
gebildeten Stoffwechselprodukte, vor allem die CO, (Sulfet**), er 

Ala genignote Darchstrimangefifissigkeit {ir das Frosehhers gab Minger™ an 
0,6°), Na Ol, enthaltond 1em® 1%, NaHOO,, Lem®1°/, Ca Ol, O,75cm 1°), KC 
Notwondigkeit resp. Ersotabarkeit der oinzelnon Salze vgl. Grose’, Bochm™): 
cine Lisang von 0,65°), NaCl, 0.1%) NaHOO,, 0,01%, KCl, 0,0065%/, Ca Cl, 
0,0008"), Na Hl, PO,. Fir das Siugetiorherx empfnh! Locke™ oine Flies 
Na Cl, 0,02—0,024"' Cu Cl, 0,02—0,042"/, K Ol, 0,01—0,03"/, Na HOC 
ist noch in Znsntz von 0,1°/, Glucose. Newkirch u. Rona® fanden am week 
die Tyrodesche Liisnng: 0.8%) NaCl, 0,02%, KO, 0.02%, Ca Cl, 0,019), Mx Cl, 
Na HL PO, 0.1% Na HOO,, 0,1%), Glncose, 

6. Zahlreiche chemisehe Substanzen wirken auf die Frequ 
Stirke der Herzbewegungen ein, wenn sie entweder direkt aut 4 
liegende Herz aufgetragen oder beim durchbluteten Herzen der 
stromungstliissigkeit zugesetzt werden; die Art der Wirkang 
Wirkung auf die Herzmuskulatur, indirekte durch Vermittlung di 
nerven, Kombination beider Einfliisse) ist dabei nicht immer kl 
Hedbom*', Harnack**), 





Na, HPO, 








Anffallond ist die giftige Wirknng der Kalinmsnlze, die in sehr 
Mengen ein notwondiger Bostandteil der Renfhrungstliissigkeit sind (vgl. oben), a 


re ~~ sowrgungen aes Herzens. 


dud dem ,clastischet ee der Lungen® (vgl. § 47), welcher, 
don Aie aktive Zusammenziehung der Vorhife beendet ist, die nt 
erailaftten, zusammenliegenden, nachgiebigen Vorhofswiinde wied: 
simanter zieht. 

B. Die Vorhéfe contrahieren sich. Hierbei erfolgen schnell 
einander: die Zusammenzichung der einmiindenden Venen, der Herz: 
der Wandungen der Vorhife. Die letzteren ziehen sich wellenférm 
oben nach unten, niimlich gegen die vendsen Ostien hin, zusammer 


Dio Contraction der Vorhito hat ein lelchtes Anstanen des Blutos in dor 
Veneastimmen zur Folge, wie man es namentlich bel Kaninchen leicht erkeonen k 
denen nach Durchschneidung der Brostmuskeln der Znsammentritt der Venae j 
communes und subclavine freigelegt ist. Ex findot kein cigentliches Zuriickworfon ¢ 
masse statt, sondern nur eine teilweise stanende Unterbrechung des EinilieBeng in | 


Wig. 22. 





D.a.-S.v. 


Schema der Systole atrioruns, Diastole ventrieulorum und der Diastole atrioram, 
‘Syetole ventriculorum. 





hof, weil die Einmiindungsstellen der Venen sich yerengern, weil ferner dar Drach 
oberen Hohlyene und in den Langenyenan der Ricksianung bald Gogengewir 
und endlich weil in der weiteren Verzweigang der interes, zum Tell auch der ober: 
vene und der Horavenen Klappen die Réckstauung verhindorn. In dem anstauende 
vonenblute bewirkt so die Herzbowegung eind regolmivige, pulsatorische Rese 
die in abnormer Hobe zum Venenp 
Durch die Zusammenziehung der Vorhéfe wird das Blut in d 
schlafften Ventrikel getrieben, wodurch diese betrichtlich erw 
werden; zum Teil wird diese Erweiterung der erschlafften Ventrike 
durch den elastischen Zug der Lungen bewirkt. Man hat der 
trikeln auch die Fahigkeit zusprechen wollen, sich aktiy zu ery 
und so das Blut anzusaugen®; cine derartige aktive Erweiterung | 
jedoch tatsiichlich nicht vor (von den Velden, ygl. S, 114). 
Wiihrend das Blut durch die Vorhéfe in die Kammern gel 
wird, liegen die Zipfelklappen keineswegs etwa der Kammerwat 


















($39.] Mie Bewegungen des Hlerions. 


Es ist fraglich, ob Vorbof und Kammer gonan alterniorend arbel 
da iin Momente des Beginnes der Kammerzusammenzichang die Vorkammer erschla: 
ob die Kammer bereits sich contrabiert, wihrend noch die Vorkummer kurze Zeit con 
bleibt, so da® also wenigatens flr eine kurze Zeit das ganze Herz contrahiert ist, 

C. Nun contrahieren sich die Ventrikel, wihrend die V\ 
erschlaffen. | 

Hierbei preft sich das Blut gegen die Unterfliiche der Atrioventri 
klappen, welche sich, mit ihren nach unten umgebogenen Randern 
formig ineinander greifend, eng aneinander legen (Sandborg u. 
Miiller*) (Fig. 23). Ein Rickwiirtssehlagen in die Vorhofshéhlen 1 
ist nicht miglich, da die Chordae tendineae ihre unteren Flicher 
Riinder festhalten. Fir die Aneinanderlagerang der benachbarten Kla 
rinder wirkt der Umstand besonders gtinstig, dai von einem Pay 
muskel die Sehnenfiiden stets an die einander zugekehrten Rinder zy 
Klappen gehen. Die geschlossenen Klappen sind der Fliiche nach annit 
horizontal gestellt; daher bleibt in den Ventrikeln auch auf der Hoh 
Contraction stets ein Rest von Blut, das sogenannte ,Residualblut' 
riick (Sandborg u. Worm-Miiller®®)_ 

Die Semilunarklappen der grofien Geftibe sind beim Begin 
Systole der Ventrikel natiirlich noch durch den hohen, in den grobe 
fiiben herrschenden Druck geschlossen. Es ist daher der Kammer 
wiibrend des ersten Teils der Systole der Ventrikel sowohl gegen den 
hof wie auch gegen die grofen Gefiibe abgesperrt; die Systole der Ka 
fiihrt daher zuniichst nicht zu einer Zusammenzichung der Kammer 
und Verkleinerang des Innenraumes, sondern nur zu einer Zunahm 
Spannung der Kammerwand und einem Ansteigen des Drackes im I 
des Ventrikels: ,Anspannungszeit* oder ,Verschlubzeit*. Erst it 
Augenblick, wo der Druck in der Kammer den in den grofen Ge 
tibersteigt, 6ffnen sich die Semilunarklappen und das Blut strimt i 
grofen Gefibe; Austreibungszeit®. 

Wahrend der Anspannungszeit {kommt es xu keiner Anderung der Lin 
Muskelfusern, sondern nur za ciner Zunahme der Spanning derselben, entsprecher 
isometrischen Maskelakt; wahrend der Austreibungsceit verkiiren sich die } 
fasern bei (angefiihr) gleichbleibender Spannung, entsprechend dem isotonischen M 
akt (vgl Muskelpbysiologie, § 216 nd 218), 

Withrend das Blut in die grofen GefiiSe strémt, legen sic! 
Semilunarklappen keineswegs etwa an dij 
fibwand an (vgl, S. 103). Bei der Contr: 
der Ventrikel werden auch die Ostien der g 
Gefiibe yerengt; dies geschieht besonders 
die Muskelwiilste, welche sich unterhalb 
Semilunarklappen hervorwdlben  (vgl. 5. 
Das Blut wird mithin durch einen engen Sp 
die weite Offnung der grofen Gefiibe gesy 
dadurch entstehen oberhalb der Klappen (i 
Sinus Valsalvae) Wirbelbewegungen, welch 
Klappen nach der Mitte des Geftibrohre: 
‘iid Slidakele Meare driingen, die Klappe ,stellen* (Krehl+, M 
Klappon der Pulmonalis rom D. Sowie die Systole der Kammeri 

Menschen (von ante). nde erreicht hat und die Diastole be 
schlieBen die Semilunarklappen (Pig. 24). Da dieselben vorher 
-gestellt* waren, erfolgt der SchluS bei dem geringsten Uberdruck it 
grofen GefiiGen, ohne da ein Zartickfliefen von Blut in den Ven 


Pig. 4. 








{$39.] Arbeit des Herzens. Pathologisehes. 


0.1885 . 70.60. 24 = 19000 kgm betragen. In Warmeeinheiten an, 
sind 19000 kgm = 45 Cal. Da der Muskel die chemische Spann] 
zu etwa '/, in Arbeit umzusetzen vermag, wiiren fiir die Leistuy 
Arbeit 3 X 4 = 135 Cal. erforderlich. Der Bedarf an Gesamtene, 
Tag kann zu 2800 Cal. angenommen werden; dayon kiimen dani 
die Herzarbeit rund +/., oder 5%/,. 


Das Herz besitzt in auGerordentlich hohem Mage die Fihigkeit, 
Arbeitsleistung den cashing ee anzupasse 
auch erhéhten Anspriichen durch SEES Arbeitsleistung 
niigen. Wenn z. B. bei Musboittigkos die Verbrennungen stark w 
sind, so muf den arbeitenden Muskeln mehr Sauerstoff, also aa 
in der Zeiteinheit augefiihrt werden. Das Herz erfiillt diese Aut Ht 
durch, da6 es die Frequenz seiner Sebliige bis auf das aweify 
Schlagvolumen bis auf das 2wei- bis dreifache und dartiber erhé 
Arheitsleistung ist dementsprechend gesteigert. Die Vergréberung des 
volumens ist nattirlich nur moglich infolge einer Vergréferang des 
raumes, d. h, einer Dehnung des Herzens: nach beendeter Arbeits! 
geht ein normales Herz wieder auf seine ‘normale Grobe zuriick. 


Pathologisches. — Werden an das Hera danornd erhihte Anforderanger 
so daB os dauernd eine gréfere Arbeit leisten mul, 
cin, Sind zngleich dabei die inneren Hershohlen erweitert, so spricht man 
exzentrischen Hypertrophie oder Hyportrophie mit Dilatation. Solch 
Anfordornngen an die Horatitigkeit worden durch abmorme Widerstiinde bedingt, 
der normalen Blnthewegung entgegonstellen, so durch Stenosen der Herzostien 
grofen GefiBe, aber auch durch Insuffizienzen der Klappen, die aur Folg 
daB yon dem cinmal ausgetricbenen Blnte stets ein Teil durch die nicht schlabfihig 
zariickstrimt, Vermag der hypertrophierto Heremuskel den erhihten Anforderunger 
zu worden and die Blathewegung in annabernd normaler Woise zu anterhalten, 80 b 
man das als Kompensation dos Klappenfehtors. Die Hypertrophie botrim 
immer den unmittelbar stromanfwiirts von der erkrankten Klappe gelegenen Herz: 
der die orhihte Arbeit zn Ieisten hat, im weiteren Verlanfe kinnon aber auch noc 
rickwiirts gelegene, sowie anch stromabwirts gelegene Herzabschnitte an der Hyp 
teilnebmen. 


So entstoht — 1. Hyportrophie des linkon Vontrikels hei Hindorn 
Gebiote des grofon Kreislanfos, und zwar vornchmlich der Arterien und Cupilluren, 
der Venen. Hierher gehiiren Stenoso des Aortenostiums und der Aorta, ferner Va 
und Undehnbarkeit der grofen: Schlagadern, unregelmiiBige Erweiterangen an ¢ 
(Anenrysmen), — Insuflizionz der Aortaklappen, bei welcher im Ventrikel stots de 
drack herrscht. Aber anch bei Mitralinsnffizienzen ist xnr Kompensation Hypertro 
linken Herevntrikels neben der des linken Atriums notwendig, — Bel Nierenkea 
kommt 08 oft 2u einer Hypertrophic des Herzens; iibor das Zastandekommen « 
gehon die Ansichten noch auseinander. 


2. Hyportrophie des linken Vorhofes tritt cin bei Stenose des linken 
Ostiums oder bei Insnftizien der Mitralis, — konsekutiy aber anch boi Insuftix 
Aortaklappen, weil der Vorhof hier den im Ventrikel ununterbrochen hurrschende 
druck an iberwiltigen bat. 


8. Hypertrophie des rechten Ventrikels entsteht — a) bei allen Hind 
wolche dor Blntstrom im Gebinte des kleinon Kreislanfes erfihrt. Diese sind: — 
idungen griBerer GefBbexirke der Langen infolge von Zerstirang oder Schrampfi 
Kompression der Lunges. — 8) Chorfillung des kleinon Kreislaufos mit Blut inf 
Stonose dos linken venison Ostiums oder yon Insnfiiziens der Mitralis, — konseku 
bei Hypertrophie des linken Vorhofos bei Aortaklappon-Insufiizienz. — b) Undichtig 
Palmonalis-Klappen, welche das Bint in die Kammor zuriickstrémen liBt, 50 daB in 
derselben ununterbrochen der Drack der Pulmonalarteric herrscht (sehr selton). 


4. Hyportrophie des rechten Vorhofes horrseht konsekutiy hei letatge 
Znstanile, ferner hei Stenoso des rochten vendsen Ostinms oder boi Insnflizienx der 
pidalis (selten). 








e404) Ine sooumerungen des Uruckes im Merzen, 


ansehlieBend eine horizontal yerlanfende oder schwach ansteigen 
absteigende Linie, das sogenannte ,,Plateau*, schlieblich wiede 
steil abfallenden Schenkel. 

Fine Relhe von Autoren haben in ihren Drackkurven das Plateau vermié} 
fallt der Druck sofort wieder, nachdem er das Maximom erreicht hat. Die Differe, 
dio verschiedene, fiir die Druckrogistrierang benntzte Methodik xurlickzufihren (vg 
u, Starling**, Porter, Frank’), Die nenesten, mit den besten Manomotern any 
Untersuchungen haben hieraber ebenfalls keine Bntscheidung xebracht: Piper 
seinen Kurven kein Plateau, im Gegensatz zu ihm halt es (, Tigerstedt® nw 
Untersuchungen fir festgestelit, da der wirkliche Druckablauf derch eine Ki 
Plateau richtig wiedergegoben wird. Ob das Platean absinkend, horizontal oder a 
verliinft, biingt nach C. Tigerstedt yon dom Widerstand im arteriallen Gobiot ab. 


Im besonderen lassen sich an der Kammerdrackkurye die fo 
zelheiten erkennen: 

Vor dem steilen Anstieg des Druckes bemerkt man eine leic 
hebung der Kurve (re in Fig. 25 B u, ©). Dieselbe fiillt zeitlich zu: 
mit der Vorhofscontraction (e¢ in Fig. 25 A), entspricht also 
hdhang des Druckes durch das bei der Vorhofscontraction in den V 
getriebene Blut. 

Zwischen der Vorhofscontraction und der cigentlichen Systole der Kamm 
Chauccau*® eine in der Kammerdrackkarve znwoilen auftretende geringe Erhihun 
or als ,Intersystole* bezcichnet. Die Dentung derselben ist nicht klar. 

is folgt der steile Anstieg des Drackes, der durch die Sysi 
Kammern bedingt wird; er geht sodann in das Plateau der Kary 

An irgend 
Wig, 26, Stelle diese 


























Semilunar 
pen erfolge 
Lage dieses 
lubt sich be: 
durch Vergl 


Kardiogramm 


Aorta 


Zaitschrolber 





der gleichzei 
genommenen 
des Drackes 
Aorta (Fig. 
Der Drack 
Aorta steigt 
demselben M 
in welchem 
Ginichentigor Abiauf dos Kardiograomer, dex Veniikeldruskes und St0le der K. 
‘*jede Zacke der Zaltkurve = 01 Sekusda. beginnt (Ze 
0), sondern 
geht eine mefibare Zeit (von Marke 0 bis 2), bis der Druck in de 
zu steigen anfiingt (Anspannungszeit, vgl. S. 109). In dies 
ment (Marke 7) erfolgt die Offpung der Semilunarklappen. 

Am Plateau der Kammerdruckkurve zeigen sich fast immer 
Schwankungen, die annten ,systolischen Wellen*. D 
yaren bei den iilteren Untersuchungen sehr wahrscheinlich zum 
Teil bedingt durch Eigenschwingungen der registrierenden Wei 
Aber auch die neuesten Untersuchungen zeigen hier vereinzelte | 
gungen; tiber ihre Erklarung s, Piper, C. Tigerstedt **, 


Landois-Rosemann, Physiologie. 14. Aufl. 


Venteihol 


























[$41] wer MerestoD- 


Dieses allein bewirkt den Herzsto$ noch nicht; aber die so der Bre 
niher gebrachte und systolisch erhiirtete Basis gibt hierdurch der 
die Miglichkeit, die den Spitzenstob selbst veranlassende Be 
zu machen. 

2. Die Ventrikel, welche in der Erschlaffung mit ihrer Spitze | 
JL. i) schief abwirts in ihrem Lingsdurchmesser geneigt sind, so) 
Winkel (# ci und aci), welche die Ventrikelachse mit dem Dure| 
der Basis bildet, ungleich sind, stellen sich als regelmabiger 


Fig. 37. 





I Horizontalschnitt dureh Mere und Lungen nebst den ‘Thorax 
der Formvorandorung der Horzbasit bei der Contraction der 
“ 7 





andungen sue Demoust 
‘ontrikel. JG Quordurchr 
eb 










der jurehmesss 
Ventrik i der 8% 
— IT Seitenansicht der 4 dio Mh der Diartole; p dierelhe in dor S 


Henke) 


mit der Achse senkreeht zur Basis, Hierdurch muf die Spitze 
unten und hinten nach yorn und oben (p) erhoben werden (W. 
Cor sese erigere*), und sic pret sich so systolisch erhiirtet in de 
costalraum hinein (Fig. 27. 17). — Da somit der Herzstob im wese 
von der Bewegung der Herzspitze herrlihrt, bezeichnet man ihn als 
spitzenstob*. 

3. Die Herzventrikel erleiden bei der systolischen Contraction 
eine leichte spiralige Rollung um ihre Liingsachse (,laterale) 
nationem*, W. Harvey) in der Art, dab die Spitze von hinten etw 
nach yorn gebracht wird, wobei zugleich von dem linken Venti 
griferer Streifen sich nach vorn wendet. 





Die Rollnng des Herzens um soine Liingsachse leitete man friher ab von den 
Verliuf der Fasorstige an der Vorderiliche des Herzons von oben und rechts 1 
und links. Boginstigt sollte dio Drohung weiterhin dadurch werden, dal die Ieiel 
gogoncinander gescbmiegtan Stimma der Aorta und Palmonalis ihror 
Spanoung ebenfalls eine Drebung des Herxens in demselben Sinne bewirkten (Ko, 





Druck der Unterloibsorgane) die Verlagerung mich oben (solbat 
dritten Intereostalraum) und otwas nach links hin aur Folge, Verdickang der 4 
dung des Herzons und Erweiterung der Hohlen und Dilatation) sn 


(Hypertrophic 
sie den linken Ventrikel betrifft, denselben linger und breiter, and der verstirkt 
Fs fiber die Mammillarlinie hinaos nach links, selbst bis in die Axillarlinie im 
& Intercostalraume fiiblbar, Hypertrophie und Dilatation des rechten Ventrikels 
das Herz; der HerzstoB ist mehr nach rechts, ja selbst rechts bt a ree er 

anch noch etwas ber die lake Mamzmillar hinans fihlbar. In 

des Situs inveraus, in welchen das Herz in der rechten Brastseite Hog, onee mar 

anch den Herzsto8 an der entsprechenden rechten Thoraxseite. 
Der HerzstoB erscheint abnorm geschwiicht bel hochgradiger Schwiiche 
aktion. Anch eine Abdriingung des Herzens von der Rrnstwand durch Ansamr 


Fig. 28. 
onStc 






































Elektrokardiogramme (nach Einthoven). 


Flissigkoiton oder Gasen im Herzboutel, oder durch die sehr ansgedehnte lin 
oder durch cine linksseitige Fillung des Thoraxranmes schwicht den Herzstol < 
ihn sogar villig ans. 

Fine Verstirkang des Hersstobes wird beobachtet bei Hypertrophie der 
sowie bei den verschiedensten Exregangen (payehiache, enteiindliche, fleberhafte, 
welche das Herz treffen, Starke Hyportrophie des linken Ventrikels macht det 
chebend*, no dal ein Toil der inken Brustwand unter systolischer Ersebfittern 
gehoben wird. In manchen Fallon flndet man ihn dontlich oder sogar noch dew 
normal, und der Pals erscheint trotzdem nur klein. Es handolt sich hier nm ao 
Vontrikelentloorung (,frnatrane Horzcontraction“) (Hochhaws u. Quincke®) 

Kin horasystoliaches Einsinken an der vorderon Brastwand findot 
nnd 4. linken Intercostalranm nicht selten unter normalen Verhiltnissen, zuma 
stirktor Horzaktion, fernor anch bei exzentrischer Hypertrophic der Kammern. I 
Kammercontraction die Heraspitzc otwas disloziert wird und die Ventrikel ung 
verkloinern, so werden zur Ausftilling des leergewordenen Raumes die nachgiobiy 
toile der Intorcostalrinme cinsinken, — Bei Verwachsung des Hersens mit dem 
nnd dem umgebenden Bindegewobe findet sich ebenfalls anstatt des HerzstoBer eine 
Finzichung der Herzsto8gegend. In der Diastole tritt dann, gewissermaBen als di 
Horzstol, der betroffende Teil der Brustwand wieder bervor. 





8 Das Eloktrokardiogramm. 


Es liegt nabe zu versuchen, die Kardiographie als diagnostisches Hil 
ittel bei Horzkrankhelten heranzuzichen. In dieser Absicht haben zuerst Land 
876) und nach ihm viole andere Untorsucher Kardiogramme bei 
‘ngen des Herzens anfgenommen, Leider wird der praktische Wart deg 
tech die groBen Schwierigkeiten, dio schon unter normaten Verhiltnissen bei der 
sselben (Ditferenzen boi verschiedenen Individaen, verschiedenen 5 
rachiedenon Stellen des Thorax usw.) und bei der Dentung der einzelnen Teile dessell 
tstehen, sehr beointriichtigt. 

Das Elektrokardiogramm*. Die Bewegungen des Herzens sind 
le Muskelbewegungen (vgl. Elektrophysiologie, $249) mit elektrisch) 
orgiingen verbunden, Man kann diese elektrischen Vorginge registrier 
dem man bei Tieren direkt von dem frei gelegten Herzen ableitet. M 
ann sie aber auch obne Freilegung des Herzens, also auch beim Mensehe 
igistrieren, da infolge der schriigen Lage des Herzens im Kérper ¥ 
yen, rechts und hinten nach unten, links und vorn die vom Herzen at 
shenden elektrischen Stréme sich im Kérper so yerteilen, da& der rect 
tm die elektrische Spannung der Herzbasis, der linke Arm und das lin 
ain die der Herzspitze annimmt. Man leitet daher yon beiden Arme 
ler vom rechten Arm und linken Bein (oder auch von Mund und Anus) 4 
ie Ableitungsstellen werden mit einem Capillarelektrometer oder 0 
‘m Saitengalvanometer (vgl. Elektrophysiologie, § 245) verbunde 
e Ausschlige der registrierenden Instrumente auf eine mit bestimmt 
eschwindigkeit bewegte photographische Platte aufgeschrieben. Die ¢ 
utene Kurve hei6t das Elektrokardiogramm. Die mittelst des Capilli 
tktrometers gewonnenen Kurven bedtirfen noch einer rechnerischen Ke 
ktur, die mit dem Saitengalvanometer gewonnenen Kurven kinnen obj 
esentlichen Fehler unkorrigiert bleiben (Waller, Binthoven®*, Kra 
Nicolai*, Samojloff*). 

Fig. 28 zeigt die korrigierte Form des mit dem Capillarelektromet 
yeichneten menschlichen Kardiogrammes, Fig. 29 das mit dem Saite 
ivanometer aufgenommene menschliche Kardiogramm. 

Das Elektrokardiogramm zeigt im wesentlichen drei Erhebungen: 
ste (P in Fig. 28) wird auf die Vorhofscontraction, die beiden folgend) 
? und 7’ in Fig. 28) auf die Ventrikelcontraction bezogen. Ober d 
entung der Erhebungen des Elektrokardiogramms gehen die Ansicht) 
och auseinander (vgl. Kraus u. Nicolai *, Kinthoven*). 

bor das Elektrokardiogramm unter pathologischen Verhiltnissen veh Ara 
Nicolai, A. Hoffmann’), 

Uber die Bewegungen des rechten Vorhofes gibt zuweilen d 
anenpuls Auskunft (ygl.$55). Die Bewegungen des linken Vorhof) 
jnnen registricrt werden mittelst einer in die Speiseréhre eingeftthrty 
mde mit einem Gummiballon am unteren Ende, auf den sich die Bew 
tngen des linken Vorhofes direkt tibertragen (Minkowski"®, Rautenberg! 
vedericg’. Janowski™). 








42. Die zeitlichen Verhiiltnisse der Herzbewegung. 


Methode, Auf dor Rogistrier 1i8t man zngleich mit den anderen Karyen ef 
itkarve anfschreiben, z. B. die Schwingungen einer Stimmgabel, welche eine hestimm 
hi von Schwingungon in der Sekunde ansfubrt ( Man kann alsdann durch dirk 
teaung fiir jeden Kurventell die augohirige Zeit bestimmen. 

Die Dauer der Systole der Kammern lift sich am 
Tieren an der Kammerdruckkurve bestimmen; die Systole dane 












Lea VIC RUseVNTN TCTUIMUSSE UEF MErEveWweEUNE. 


yom sates des aufsteigenden Sebenkels bis zum Endp 
Plateaus (Marke 0—2 in Fig. 26). 

Nach Hirthle® kann die Daner der Systole auch an der Kurve dex A: 
gemessen werden; die Strecke vom Beginn des Pulses bis sum Anftreten der ¢ 
Welle stellt ziemlich genan die Daner der Kammersystole dar, obwobl sie sich 4 
mit dieser Phase der Herarerolutian deckt, 

Beim Hund fand Hiirthle™ die Dauer der Kammersystole 
0,20—0,22 Sekunden. 

Beim Menschen ist man fiir die Bestimmung der Syst 
auf das Kardiogramm angewiesen. Bei manchen (,typischen*) 
grammen entspricht in der Tat der Beginn des ansteigenden ¢ 
dem Anfang der Kammerzusammenziehung, der Beginn des steilen 
nach dem Plateau dem Anfang der Diastole, aber es gibt auch 
gramme (,atypische*), bei denen dies nicht der Fall ist, ohne 
es an der Kurve selbst entscheiden kénnte, Man muf hierftir den” 
mit der Pulskurve heranzichen, bei der (s. 0.) die Strecke vom Be 
Pulses bis zam Auftreten der dikrotischen Welle der Dauer der 
systole gleich gesetzt werden kann. Auch die Markierung der 
kiime hierfir in Betracht, 

Hiirthle® bestimmte die Daner der Kammersystole beim } 
zu 0.26 Sekunden. — Landois™ herechnete die Dauer der Ventrik 
aus seinen Kardiogrammen za 0,32—0,29 Sekunden; bei nur 
schliigen war der Wert 0,34 Sekunden; bei sehr hoher Frequenz 
bis 0,199 Sekunden. 

Die Systolendauer stellt einen ziemlich konstanten Wert 
wird dieselbe durch wechselnde Widerstiinde in der Aorta nicht b 
sie ist also (wenigstens innerhalb weiter Grenzen) unabhingig 
Arbeit, welche das Herz bei seiner Zusammenziehung leistet. Veriin 
in der Pulsfrequenz werden hauptstichlich hervorgebracht durch 
tinderungen in der Dauer der Diastole, nicht der Systole. 

Landois fond, daB bei enornier Hypertrophic und Dilatation des linken 
die Daner der Ventrikeloontraction den normalen Wert nicht wesentlich fiberstei; 

Die Zusammenziehung der Ventrikel zerfillt in zwei A 
(vgl. 8. 109): die ,Anspannungszeit" und die ,Austreiban 
Die Grenze zwisehen heiden bildet der Moment der Offnung der S¢ 
Klappen. Dieser Moment kann bei Tieren durch Vergleich der 
druckkurve und der Aortadrnckkurve bestimmt werden (Fig. 26, | 
In den Versuchen Hiirthles am Hunde betrug die Anspannung 
Durchsehnitt 0,02—0,04 Sekunden. 

Am Menschen kann man die Anspannungszeit bereehnen 
Zeitdifferenz zwischen dem Beginn des Kaiapratita und den 
der Pulskurve in einem dem Herzen naheliegenden Gefib; di 
dabei die Fortpflanzungsgeschwindigkeit der Pulswelle (ygl. § 
Rechnung gestellt werden. Auch bleibt zu bedenken, da® der Be 
Kardiogramms nur in den typischen Kurven mit dem Beginne der | 
systole zusammenfiillt. 

Landois berechnete die Anspannungszeit in folgender Wei 
1. Herzton bis zum Puls in der Axillaris verstreichen 0.1378 
Die Fortpflanzungsgeschwindigkeit der Pulswelle in der 30cm 
Strecke von der Aortenwurzel bis zur Axillaris betriigt 0,052 ¢ 
(berechnet ans der Geschwindigkeit in der 50 em langen Bahn 
Axillaris bis Radialis = 0,087 Sekunden); es bleibt also fir 


Die Ursache des LE Bere in den $ 
gungen der BonilunarElapp diese die plitati 
spannung bei der Erscht: ey Veuutbel 5 ersetzt werden, Der 





‘Topographic des Hrustkorbes und der Mrastoingewelte, 
ad. Atriam dexteum. — 0. x. Au alee, —— td. Vantrioulas exter. — 
A Ventrieulue snietor mit J, dae Heraspi ‘Artoria pulmonalis, = 
C Vena avs rior, — — PP Bogrensung der Flown 
paitoeals (nach Duseh). 












der Semilunarklappen selbst findet tonlos statt; erst einen Au 
spiiter, wenn dieselben stiirker gespannt werden, erschallt der 2. | 

Registrierung der Herztine, Da man weiS, in welchem Moment « 
bowegung die Heratiine erschallon, so ist ihre objektive Rogistrierung von gril 
far die Dentung der Kurven dar Horzbowegung. Fir diesen Zwock sind sahlreiche 
ungogeben worden. Entweder werden die Herzténe auf ein Mikrophon thertrag 
Sffoot und schliebt durch seine Schwingungon einen oloktrischen Strom, wor 
Elektromagnot in ‘Ditigkelt gesetzt (/Jarthle™) oder ein Capillarolokteometor (Hin 
Geluk) oder der Faden eines Saitongalvanomoters (Kinthoren'', Kahn!) bew 
oder die Schwingnngen der Herztine werden anf eine Mombran tbertragen: ei) 


19sey AMCIRUAAEIL UNE CURUrACUMAL UES cerzurUsAcis. 


stillstehende oder auf das infolge der normalen Spontanreize pul 
Herz kiinstliche Reize, sog- Extrareize (meist Induktionsschl 
wendet und die Bewegungen registriert. 

Die Untersuchungen konnen sowohl an dem freigelegten, in der normalen V 
belassenen, als anch am anageschnittenen und eventuell kiinstlich gespelsten Her 
‘Mhrt warden, Um die Bowegangen der cinzelnun Herzabsebaitte xu rogistrieren, 
feine Hiikehen durch die Herzwand und verhindet diese darch einen Faden } 
Sehreibhebel. der die Bewegungen in gocigneter VergroBernng aufzeichnet (Susp 
mothode, Engelmann"), 

Anatomia des Froschherzons, — Das Froschhorz, an dem viele dor 
sesiorenden Untersuchungen ansgefthrt worden sind, bestebt aua einer Kammer 
Vorkammorn. In den linkon Vorhof mindet die Palmonalvene. Die Hoblvenen (2 
eine mntere) minden nicht direkt in den rechten Vorhof, sondern bilden zuniichy 
gynanntor Hohlvenensinus, dor durch ein Ostiam mit dem rechten Vorhof vert 
Ex schligt zaniichst der Hoblvenensinus, duranf die Vorhofe, dann die Kammer, ¢ 
Balbus cordis, der letzte Herzabschnitt, der in das Anfangestick des artericllen Get 
ibergebt. 

1. Reizbarkeit und 2. Contractilitut. 

Der Herzmuskel hat ebenso wie die tbrige Muskulatur die Fi 
auf Reize zn reagieren, und zwar dadureh, dab er eine Cont 
ausfihrt. Die Reizbarkeit des Herzmuskels ist nicht etwa nur d) 
zahlreichen, in ihm vorhandenen Nerven vermittelt (indirekte R.). 
sie ist eine dirckte. Dies wird durch folgenden Versuch bewiese 
bei einem Frosch die Herzspitze (die unteren zwei Drittel der Herzk 
welche nur Nervenfasern, keine Ganglienzellen enthilt, abgekler 
wiissen die von den Ganglienzellen getrennten Nervenfasern in d 
degenerieren. Die Herzspitze bleibt aber bei solehen Frischen, die 
lang am Leben erhalten werden kinnen, dauernd reizbar: auf Be 
macht sie eine cinmalige Contraction (Bowditch 197, Aubert %, Langent 
— Ammoniak, Kalkwasser, sehr yerdiinnte Mineralsiiuren, die auf mc 
Nervenfasern nicht reizend wirken, wirken auf den Heramuskel: 
triertes Glycerin, welches Nerven stark reizt, ist an der Herzsp 
wirksam (Langendorff). 

Ein wesentlicher Unterschied im Verhalten des Herzmuskels 
her dem Extremitiitenmuskel liegt darin, dab die Grobe der Cor 
nicht von der GréBe des Reizes abhiingt. Auf einen bestimmt 
reagiert der Herzmuskel entweder tiberhaupt nicht, wenn niin 
Gribe des Reizes unter der Schwelle der Wirksamkeit liegt (unterm 
Reiz) — oder, falls der Reiz tiberhaupt wirksam ist, sogleich 1 
maximalen Zuckung: Alles- oder Nichts-Gesetz; der mi 
Reiz hat bereits maximale Wirkung (Bowditch’”, Kronecker 
Herzmuskel yerbraucht also auf einen tiberhaupt wirksamen Reiz h 
alle ihm angenblicklich zur Verfiigung stehende Energie. 

Aus diesem Verhalten des Herzmuskels erkliiren sich ein 
weiterer Kigentiimlichkeiten desselben: 

Auf jede Zasammenzichung des Herzens folgt eine Periode, in 
die Empfituglichkeit fiir weitere Reize (ebenso das Leitungsve 

ngelmann) aufgehoben, resp. herabgesetzt ist: ,refraktiire P) 
(Bowditch ©", Kronecker®, Marey™), Exst nach Ablauf dieser Zeit 
Herz wieder ftir neue Reize erregbar. Da eben bei jeder Contrac 
yorhandene Energie aufgebraucht wird, maf nach einer solchen ¢ 
gewisse Zeit verstreichen, bis die ftir eine neue Contraction not 
Energie sich wieder aufgespeichert hat. 


ey sem = Sunsrananewne ps aseremnaners 


der Daver der normale Periode von dem Anfang der letzt vorher, 
Spontanen Systole entfe™t. 

‘Wenn aie spontanen noe cines Herzens in vorbiiltvismafig lunge 
aufeinander folgen, so kann “® refraktiire Periods einer Extrasystolo, die mig! 
nach einer spontanen Systole ingeschaltet wird, schon abgelaufen sein, wenn | 
spontane Reiz erfolgt; in diesem Fall fillt naturlich dio niichstfolgende Systole 
sondern tritt in dem normalen Zeitpnnkt in. Die Extrasystole ist dann einfael 
‘uwei spontane Systolen cingeschaltet; die Zeit von der Intzten spontanen 
Extrasystole bis zur niichsten spontanen Systole nach ihr ist dann also gleich de 
Periods (gleich dem einfachon der normalen Periods). Es ist dies also nur ein 
Fall des allgemeinen Kngelmannschen Gesotzes, 

Die Stirke der Contraction des Herzmuskels ist abhit 
der Dauer der vorhergegangenen Pause. So zeigt z. B. die 
Extrasystole folgende niichste spontane Systole eine deutliche Ver 
(kompensatorische Systole, Langendorff"), sie ist um so st 
Kleiner die Extrasystole und je linger die Pause war. 

In der Pause hiinft sich um so mehr Energie fir die neue Contraction ar 
dig Pause ist. Da die komponsatorische Panse nach einer Extrasystole linger i 
swisehen zwei spontinen Systolen verstreichende Pause, erklirt sich hierans oh 
die Verstiirkung der kompensatorischen Systole, 

Wonn man auf die rohenden Ventrikel intermitticrende Rinzelreize ¢iny 
so ist die Stirke der Contractionen um #0 grober, je Kinger das zwischen den 
Jegene Zeitintervall ist. Mit der Verlingerung der Pansen wachst die Starke dar Cc 
bis xu viner bestimmten Grenze: dem Optimam des Reizintervalls, Wird die Paust 

Optimum hinaus verlingert, so nimmt die Stirke der Contractionen wird 

Wenn man nach lingorem Stillstande das Herz in karzen Intervallen 
reizt, so nimmt die Contractionsgrife vom Anfange der rhythmischen Relzung 
miblich bis zn einem bostimmten Maximum zu: Bowditchsehe'™ Troppe, 

Der Herzmuskel kann unter normalen Verhiiltnissen nich 
tanus yersetzt werden, Diese Eigentiimlichkeit ist offenbar dure 
fraktire Periode bedingt: da jede Contraction erst abgelanfen + 
ehe ein neuer Reiz wirksam werden kann, kann es nicht zu e 
schmelzung von Einzeleontractionen kommen. 

Das mit Moskarin vergiftete Herz kann in Totanns versetzt worden; bel der 
wirkung ist die refraktlire Periode verkiirt (Walther *). — Auch wihrend der Vi 
Xano wahrer Totanus des Herzens hervorgernfen werden (Kouget™*, Krank), By 
Langendorff durchbluteten Warmbliterherzen beobarhtete Tetanus Danilewsky" 


Der Herzmuskel hat die Fihigkeit, auf Dauerreize rhyt! 
Contractionen auszufiihren. Auch diese Erscheinung ist zurich 
auf das Bestehen der refraktiren Periode; durch dieselbe wird di 
reiz gewissermafen in einen periodischen’ verwandelt. 


Solche Danerreize sind: 1. chemische: dic abgeklermamte Herzspitee, wol 
spontan puisiert, wird durch Auflegen eines Kochsnlzkrystalles, durch Anniihe 
mit Ammoniak befenchteton FlieSpapiorstreifons usw. in rhythmische Contraction 








Aubert, Liwit ™*); 3. 
Trendelenburg ™'); 4. analog wie ein Daverreiz wirken schnell anfeinander 
Indnktionssohlige, Sis erzengen natirlich keinen Tetanus, sondern eben 
mische Puisationon, deren Zahl natirlich geringer ist, als die der Reize, wenn dies 
onfeinanderfolgen, daS einzelne Reize in die rofraktire Periode fallen; bei lang 
einanderfolgenden Rejzen entspricht jedem Reize eine Contraction (vgl. Trendel 
Nach Rohde '™ behiilt in der Chloralvergiftung der Heremuskel die Ki 
dor Belzbarkeit, Contractilitit und Rrregungsleitung, dagegen ist die refraktar 
and die Rhythmizitat auf Danorreize aufgehoben, 


Da der Herzmuskel auf Grund der Eigentiimlichkeit der re 
Periode auch auf Dauerreize rhythmische Contractionen ausfiihrt, s¢ 
die Ursache fiir die spontanen rhythmischen Systolen eh 
Dauerreize wie periodische Einzelreize sein. Aus dem Auftreten 





wy svacne Uer Merzbewexung. 


45. Die Ursache der Herzbewegung. 


en 

Da das aus dem Bitper ausgeschnittene Herz seine Tatigke 
uunvertindert fortsetzen k4" (zumal bei gleichzeitiger Ernithrang, vg 
so kann es keinem Zweifel unterliegen, dab die Ursache de 
bewegung im Herzen selbst gelegen ist und nicht etwa a) 

lben, im Centralnervensystem. Das Herz hat die fuhigkeit, 
Auslisung seiner Contractionen nétigen Reize in sich selbst zu e) 
Antomatie des Herzens. Es miissen ferner offenbar Kinrichtu) 
Herzen selbst vorhanden sein, welche bewirken, da® die Musk 
jedes einzelnen Herzabschnitts (Sinus, Vorkammer, Kammer, Bulb 
anniihernd gleichzeitig zusammenziehen, dab dagegen die Contractic 
einzelnen Herzabschnitte in bestimmten zeitlichen Abstlinden auf 
folgen, damit die normale Fortbewegung des Blutes durch die He 
zustande kommen kann: Coordination der Herzbewegung. 

Bei der quergestreiften Skelettmuskulatur sind sowohl d 
erzeugung als auch die Einrichtungen fiir die Coordination 
wegungen in das Centralnervensystem verlegt; von hier aus flie 
Skelettmuskulatur die fir die Bewegung nitigen Reize in der ge 
Weise zu, um coordinierte Bewegungen auszulisen. Es erscheint 
am einfachsten, anzunehmen, da auch beim Herzen die + 
yorhandenen nervésen Elemente, Ganglienzellen und Nery 
der Sitz der Reizerzeugung und der coordinatorischen Einric 
seien: Neurogene Theorie der Herzbewegung"?, Zur Stlita 
Anschauung wird die Tatsache angefiihrt, dai Teile des Herzmus 
dann eine spontane, nicht darch iiufere Reize bedingte Tatigkei 
sollen, wenn sic Ganglienzellen enthalten. Die abgeschnittene od 
Klemmte Herzspitze des Frosches, die keine Ganglien mehr enthi 
harrt in dauernder Ruhe, bei Zufiihrung tuberer Reize dagegen co. 
sie sich (auf einen Stich hin eine Contraction, anf Dauerreize hit 
mische Pulsationen). — Ebenso verhiilt sich die Kammerspitze de 
tierherzens, ebenso die isolierten, ganglienfreien Herzohren beim $ 
(Langendorff **). — Dagegen zeigt die in der Atrioventrikulargren 
quetschte Herzkammer, die sicher Ganglienzellen enthiilt, beim Wa 
wie beim Frosch kriiftige, anhaltende Pulsationen. 

Nach der neurogenen Theorie sind im Herzen mehrere ga 
Oentra vorhanden, welche dureh Leitungsbahnen miteinander in 
dung stehen. Die einzelnen Centra sind einem dominierenden 
untergeordnet, yon dem aus in bestimmter Ordnung die Ri 
ibrigen Centren zuflieben; so kommt die Coordination der 
bewegung zustande. Das dominierende Centrum liegt in den Vo 
beim Frosch im Hohlyenensinus. 

Im Gegensatz zn dieser Anschanung nimmt die myogene 1 
der Herzbewegung '* an, dab die im Herzen gelegenen Gangli 
und Nervenfasern tiberhaupt nichts mit der Reizerzeugung und Re 
m tun haben. Es sind vielmehr die Muskelzellen des Herzen 
welche automatisch die motorischen Reize fiir die Herzschliige e 
die Muskelzellen des Herzens selbst sind das excitomot 
Centralorgan. 

Diese Anschauung stiitzt sich vor allen Dingen auf die 1 
dab das embryonale Herz verschiedener Wirbeltiere bereits 
ehe noch Ganglienzellen in demselben nachgewiesen 


($45) dig Ursache der Herzhewegung. 


Ventrikel vorkindot; erst O85!" Durchschneldung dieser Wetaton Betoke teitt dor 
eln (F. B. Hofmann). ABS” 8 dem mit Atropin vergifteten Herzen, bei den 
des Vagus golihmt “Ind, so daS Vagusroizung keine Herahemmang meh 
(vgl. 8.183), tritt nach det “Mten Stanninsschon Ligatur deraelbe Erfolg ein (2 
Eine noch genanere Lokalisierung der reizerzeugenden 
im Venensinus, resp. rechten Vorhof ermiglichte die Methode d 
begrenzten Erwiirmung oder Abkiihlung bestimmter Her 
Gaskell™™ und Engelmann hatten bereits gezeigt, dab eine Ai 
der Frequenz der Herzseblige, d.h. also eine Anderung im Tem 
Reizerzeugung nur dann eintritt, wenn Sinus und Vorhof o 
eve. Heravenen erwiirmt werden; alleinige Erwiirmung des Ve 
erh@ht nicht die Frequenz, sondern nur die Stiirke der Zus: 
jehung, bewirkt also nur Anderungen der Contractilitit, nicht de 
erzeugung. Die Methode ist dann durch Adam, Ganter u. 2 
Bra g u. Hoffmann*** zu einer grofen Vollkommenheit g 
und auch auf das Warmbliiterherz angewendet worden. Die Untersuc 
ergaben, dab beim Warmblliterherzen der wirksame Bezirk, durch 
Erwirmung oder Abktihlung die Frequenz der Herzsehliige geiindert 
Kann, in der Wand des rechten Vorhofs zwischen den Miindungen der 
Hohlvenen liegt; er fillt zusammen mit dem Gebiete des 
Flackschen Sinusknotens (vgl. 8. 102). An dieser Stelle ent 
in der Norm die Ursprungsreize fiir die Herzbewegung. D, 
besonderen Verhiiltnissen (s. unten) auch andere Abschnitte des spez 
Muskelgewebes des Herzens als Reizbildungscentra fungieren kinne! 
der Keith-Flacksche Sinusknoten im Gegensatze zu diesen a 
miires Reizbildungscentrum und die hier entstehenden Reize als 
tope Ursprungsreize (Hering) bezeichnet. Die Reize entsteh 
in Form von Dauerreizen (wie aus dem Fehlen der kompensate 
Pause an diesen Stellen hervorgeht, vgl. 8. 126), diese Dauerre 
wirken infolge der physiologischen Eigentiimlichkeiten des Hera 
rhythmische Zusammenziehungen, sie werden gleichsam in Einzelreize 
Welcher Art die Danerreize am vendsen Ende des Hergens sind, ist un 


vielleicht handelt es sich um eine erregende Wirkung der in der Muskulatar abl 
Stoffwechselvorginge. 


Auber dem Keith-Flackschen Sinusknoten kommt auch den 
Abschnitten des spezifischen Muskelgewebes des Herzens die Pahigk 
automatischen Reizerzeugung zu, wenn auch in geringerem Male; ¢ 
entstehenden Ursprangsreize werden im Gegensatz zu den an der n¢ 
Reizbildungsstiitte entstehenden nomotopen als heterotope bea 
Solche Stellen sind: der Tawarasche Atrioventrikulark note 
$. 102): sekundires Reizbildungscentrum, das Hissche | 
tertifires Reizbildungscentrum. In der Norm kommt die Autc 
dieser Teile nicht zur Geltung, da ihnen fortgesetzt vom Sinu: 
rhythmische Reize in schnellerer Folge zuflieben, die die Freque 
Pulsationen bestimmen. Wenn jedoch aus irgend einem Grunde die | 
Reizbildungsstiitte des Sinusknotens ausgeschaltet ist, dann ka 
Automatic der untergeordneten Reizbildungsstiitten wirksam und di 
yon hier aus zum Schlagen gebracht werden. Je nachdem die R 
solchen Fiillen vom Tawaraschen Knoten oder yom Hisschen Biind 
gehen, d. h. von einer mehr im Vorhof oder mebr im Ventrikel gel 
Stelle, kinnen in der Schlagfolge des Vorhofs und Ventrikels ch 
ristische Anderungen eintreten: die Zeit 2wischen Vorhof- und K) 


Landols-Rosemaun, Physiologie. 14, Aut. 


= 


peeing 
Ts46) 99 Con aterscacven ant iia Barshai 
Vo 
be den arn 0 pina snmer jun Kammer) enfolgt die Lei 
ims SCP r Zuckung eines quergestreiften 
‘vergleichbar), Dos Reiz!tungseysiem hingogen, welches die verb 
Briicken zwischen jene! Cinzelnen Abteilungen bildet, leitet lang: 
meting a jede einzelne nee ae sich als tin 
gut wie gleichzeitig zusammen, wogegen di tole einer jeder 
abwirts en Herzabteilung erst nach einer merklichen (21 
les Blutes aus der einen in die andere Herzabteilung geni 
Zeit erfolgen kann. Auf diese Weise kommt die Coordination 
wegung der einzelnen Herzabschnitte zustande. 


Beim Warmbltiterherzen erfolgt die Obertragung des Reizes 
Vorkammern auf die Ventrikel durch das Hissche Biindel: His? 
achtete, dafi nach Durchschneidung des Biindels Vorhof und Ka 
ganz verschiedenem zane sciilagen, Hering*** zeigte, dab nach 
sehneidung dieses Biindels jede funktionelle Verbindang von Vor 
Kammer anfgehoben ist; Vorhife und Kammern schlagen unab 
yoneinander (die Kammern seltener), beide automatisch (Fel 
kompensatorischen Pause am Ventrikel), weder von den Vorhi 
Kammer noch umgekehrt geht eine spontane oder kiinstlich a 
Erregung tiber (vgl. Cohn u. Trendelenburg***, Eppinger u. Rothbe 


Pathologisches. — Kine Leitungsunterbrechuag im Hisschen Bir 
such beim Menschen zu Dissoziation des Vorhot- und Kammerrhythmus: Adam- 
Krankheit (vgl, His!) 





46. Die Wirkung der Herznerven auf die Herzbeweg 


Anatomisches,'" — Den Plexus cardiacas bilden: — 1. Die Raw 
des N. Vagus-Stammes; dasn Aste gleichen Namens ans dem Ram. externas de. 
gous superior, des inferior, mituntor auch der Langeniste yom Vagus, xahlroic 
ls links. — 2. Die (an Zahl und Stirke nicht selten wechselnden) Rami cartiac 
modins, inferior und imus ans den drei Halsganglien and dem ersten Brostgan) 
stellatum) des N.sympathicus [mitunter verliimft ein Zweig eine Strecko w 
Bahn des Ram. descondens hypoglossi|. Aus dem Gellechte gehen hervor: die tiofe 
oberflichlichen Nerven (dio leteteron in der Regel an der Teilang der Pulmo 
dem Aortenbogen ein Ganglion enthaltend). Man unterschoidet: 


a) den Plexus coronarins dexter ot sinister, der die vasomot 
Nerven der KranzgefiiBe durch den Vagusnnteil, die dilatatorisehon du ot 
thicns fhrt (Maase**', Langendorjf*). Nach Dogiel u. Archangeleky'™ verlante 
die vasomotorischen Nerven durch den Sympathicus. 





b) die in der Horzeubstans und in den Farchen liegenden Nerve 
reichlich mit Ganglienzellon vorsohon sind, Kin ganglionreichor Nerven 
Vinft im Herzen, dem Rando des Septum atrioram entsprechend, — ein ander 
Atrioventrikulnrgrenze. Wo heide sich treffon, tauschon sie Fasorn aus. Die Gang! 
meist naho dem Perikard. Bel Singern liegon die beiden griBeren Ganglion nah 
wiindang der oberon Hohlvene, — hei Vigeln liogt der griBte Nervenknoton an dk 
Kronzungsstello des Sulcus Jongitndinalis und transversalis, Von diesen mit Gan 
dnmhestzten Ringen hohren sich nun in die Muskelwinde der Vorkammern und 
frinore Neboniistehen cin, welche anch ihrerseits wieder kleiners Ganglienzolly 











Roim Frosch ist der Vagus der einzige Nerv, dor zum Horxen tritt: 
faufon in seiner Bahn schon vom Anfang an auch sympathiache Fasern, 1 
Rami cardiaci (vom rechton und linken Vagus) teoten in die Wand des Hohl 
tin and bilden hior einen Ploxus, dem zahlreiche Ganglienzellen oingolagert sind: 
Scher Hanfen; cine kurze Anastomose verbindet hier die beiden Norven. Dio F 
bilden der vordere (hauptsiichlich Fortsetzung des rechten Vagus) und hinte 
Michtich Fortsotzung des linken Vagus) Scheidewandnery, welche an der A 


(847) GogerseF®""” Beeintiussung awischen Herz and Lunge. 


Die Nerven des Herzens gehiren dem autonomen System 
$270); der N. acceler" stammt aus dem sympathischen Sy! 
engeren Sinne, der N- Ygus aus dem parasympathischen bi 
System. Diese ZugehONigkeit kommt in der Wirkung gewisser G 
‘Spezifisch auf die autonOmen Systeme wirken, sehr deutlich zum A) 
Adrenalin, welches auf alle Pasern des sympathischen Systems « 
wirkt, hat am Herzen dieselbe Wirkung wie Acceleransreizung: 4 
stehende Herz kann durch Adrenalininjektion wieder zum Schla; 
bracht werden (§ 192. II). Auf die parasympathischen Systeme wirkt 4 
lahmend, Musearin erregend. Am Herzen bewirkt daher Atropin 
Whmung, nach Injektion von Atropin ist keine Wirkung vom Va 
anf das Herz zu erzielen; Atropinvergiftung fihrt infolge des W 
der normalen Vagushemmung zu starker Pulsbeschleanigung. Mt 
bringt das Herz zum Stillstand wie Vagusreizang; durch nachtriiglich 
kation von Atropin wird dieser Stillstand wieder aufgehoben (vgl. 


Die Hemmungsnerven des Herzens endigen im Herzen an Ganglienze 
gganglioniire Fusern, ygl. § 270), nach Marchand n. Meyer liegon diese Ganglienz: 
Kaninchen an der Hinterwand des rechten Vorhofes unterhalh der Einmtindung d 
Hoblyene; von den Ganglienzellen ans verlanfen dann die Achsencylinderfortsiite 
Nervengetlecht in der Muskulatur. Die Firderungynerven dagegen verlanfen im He 
Unterbrechang durch eingeschaltote Ganglienzellen direkt zur Muskulatnr; in ikre 
‘sind dig Ganglienzellen schon auSerhalb des Herzens (im Ganglion stellatum and 
Cerviealganglion) eingeschaltet (Hofmann, Hering), 


Im intakten Korper erfolgt die Erregung der zum Herzen verla 
Nerven durch Vermittlung der in der Medulla oblongata ge 
Centra auf dem Wege des Reflexes. Von sehr vielen Kérperstel 
kann reflektorisch regulierend auf die Herzbewegung eingewirkt 
(Engelmann **). Aber auch yom Herzen selbst aus verlaufen centr 
Fasern, deren Reizung Reflexe auf das Herz heryorrnfen kant 
kens 7); vgl. Centrum der Hemmungsnerven des Herzens und Cent 
besehleunigenden Herznerven, § 280 u. 281. 


Friedenthal*™ konnte Tiere nach Ausrottung aller ex} 
dialen Herznerven am Leben erhalten. Selbst nach Monaten 1 
Erscheinungen hiernach sehr gering; doch verlieren die Tiere die F 
a erheblicher Arbeitsleistung. 


47. Gegenseitige Beeinflussung zwischen Herz und Lu 


L Einwirkung der Lungen auf die Herztitigkeit. Die 
befinden sich im Thorax in cinem Zustande elastischer Spa 
(vgl. $72); sie sind ther ihr normales Volumen gedehnt und da 
strebt, sich auf ein kleineres Volumen (wie sie es im erdffneten 
im kollabierten Zustande einnehmen) zusammenzuziehen. Sie tiber 
einen elastischen Zug aus, auf die Thoraxwandung im Sinn 
Zusammenziehung, auf das zwischen den Lungen gelegene Herz it 
tiner Erweiterung. Dieser elastische Zag der Lungen ist um so 
je mehr sich die Lungen bereits zusammenziehen konnten, also 
ringsten bei stiirkster Exspirationsstellung, um so grifer, je stir 
Lungen ausgedehnt sind, also am hiéchsten bei sttirkster Inspirations 

Bei stiirkster Exspirationsstellung des Brastkorbes, bei welcl 
der Rest des noch wirksamen elastigchen Zuges der Lungen nur ge 


isang vueges “~SuMIUSsIng zwischen Merz und Lunge, 


Wird der mhore “Untichst in die tiefste Inspirationsstel Ix; 
hierauf die Glottis @°SChlossen und nun durch Wirkunge d 
tionsmuskeln der Bru8"4um stark verkleinert, so kénnen die 
so stark pail aie werden, dai sogar die Blutbewegang 
zeitweilig unterdriickt Wird (. Va/salvas Versuch*, 1740). Der 
Zug ist in dieser Stellung sehr beschriinkt und hierzu wirkt nw 
unter hohem Drucke stehende Lungenluft pressend auf das Her 
intrathorakalen Geftiée. Von aufen kann kein Venenblut in den 
eintreten, es schwellen daher die sichtbaren Venen, das Blut de 
wird schnell in das linke Herz beftrdert und dieses entleert 
nach aufen. Daher sind die Lungen blutarm und die Herzhé| 
Also herrscht griferer Blutreichtum im grofen Kreislaufe, geri 
kleinen und im Herzen. Die Heratiine hiren auf, die Pulse schy 

Wird umgekehrt in stirkster Exspirationsstellung die G 
sehlossen und nun mit aller Anstrengung der Brustkorb inspirat 
weitert, so wird das Herz gewaltsam dilatiert; denn auber dem e 
Zuge der Lungen wirkt noch die stark verdtinnte Lungenluft a1 
anf die Herzhihlen. In das rechte Herz ergiefit sich reichlich d 
strom; in dem Mabe ferner, wie der rechte Vorhof und die Kai 
Zug nach auben noch tiberwinden kinnen, werden sich die ] 
der Lungen stark mit Blut filllen. Aus dem linken Herzen wird 
weniger Blut ausgetrieben, so daf sogar die Pulse stocken kénn 
ein prall gefllltes, grofes Herz und griferer Blutreichtum de 
Kreislaufes gegentiber dem grofen (Johannes Millers Versuc 

Die Vorkleincrang und VergroBerung des Horzens beim Valsalvagchen u, + 
sehen Versuch kinnen durch das Rintgenverfahren direkt beobachtet werden (I 

Der Fig. 31 dargestelite Apparat zeigt schematisch den EinflaS dor | 
spirationsbewogang anf die Ausdebnang des Horzens und den Strom in den | 
bahnen, die zum und yom Herzen fibron. Kine Glasilasche mit abgusprangtem 
den Thorax dar, an Stelle des Flaschenbodens ist D, eine alastische Gummim 
gubracht, welche das Zworchfoll rprisentiort. PP sind die Lungon, L die Luft 
Fingnag (Glottis) durch einon Habn betiebig goschlosson werden kann, / ist das Her: 
der Hohlvenon, A das Aortonrohr, Wird xuerst der Luftrohrenbahn goschloss 
wie bel I die Exspirationsstellang mit Vorkloinorang dos 'Thoraxranmes herboigy 
Anfwiirtsprossnng yon D, so wird die Loft in PP verdichtot, xugleich aber wi 
Herz H komprimicrt; das vonise Ventil schlioSt sich, das arterielle wird gout 
Flissigkeit durch A ansgetricbon. Das cingeactzte Manometer M xeigt den 
Intrathorakaldrack an. — Wird gleichfalls bei geschlossenem Hahn / (in If) die 
stark abwiirts gezogen, 40 erwoitern sich die Lungen pp, aber anch das Herz h 
Kinppe fiffnet sich, die artorielle schliet sich, os erfolgt also Kinstrémen 
Flissigkeit von ¢ zum Herzen hin. 

Il. Kinwirkung der Herzbewegungen auf die Langen. Da ¢ 
Innern dos Thorax wihrend der Systole einen Kleineren Ranm ¢innimmt als ) 
Dinstolo, so mul bei offener Glottis, wenn es sich verkleinert, Luft in den horas 
wonn os erschlafft, seiner VergriGorung entsprechend, Luft durch die gotffnete 
entwoichen. Einen gleichen Rinflod mnf der Fillongsgrad der grofen intrathora 
stiimme haben, Die hierdurch auch bei stillstehender Atmung bewirkte Bewegung 
Inft wird als .kurdiopnoumatische Bewogang* bezeichnet; sie kann dur 
Vorrichtungen demonstriert und sogar graphisch registriert werden (Landois) 
der Deutang der dabei gewonnenon Kurve muS auf die Originalarbelton vorwh 
(Londois, Hayeraft u. Edie, Harris‘), 


Literatur (§ 36—47), 


1. LE. Krehl: . A17, 1891, 341, — 2 B. Albrecht: Der Horamuske 
Bedeutung fiir Physiologie, Puthologio und Klinik des Herzens, Berlin 1908. — 8.2 
fassende Darstellung: J. Kalbe: Das Reizloitungssystom im Horzon, | 


ees ean Vy UHH 


&  ladeig: 1.8. 20, 1888, 89. — 95. L. Krehl: A. P. 1889, 253, — 96. 
B. 12. Lo. 2). ML Halls Vi. 1896. VA. 141, 1895, 1.'M. m, W. 196 
vi Wintrich = aime physmoed. Sozietit x, Relangen 7, 1875, ot — 98. J, 2 
J.o.P. 11, — 9. K. Hirthle: B.A. 60, 1895, 263. — 100. W. E 
Wedd Geluk: PA BF, 1894, 617. ~~ 101 W. Einthovens PLA. 117, 19 
102, F. H. Kahn: PA. 193, 1910, 597. 140, 1911, 471. — 103. 0. Weis: Ai 
|. 9, 1907, 483, (un. G. Joachim) P. A. 128, 1908, 341, Phonokurdiogramm 
a a sbysiol. Vortrige. Jona 1909. — 104. H. Gerharts: Z. 0. Po a.T. 5, 
PA, 1910, 100. Di Die Registrierang des Herzschalles. Berlin 1911. — 105. 2 
fagsonde Darstellung: 0, Langendorff: FP. I, 2, 1902, 263. TV, 190 
106, Th. W. Engelmann: P. A. 52, 1892, 357. — 107. H. P. Bowditch: Ta. B, 28 
Jo. P. 1, 1878, 104, — 108, H. Aubert: P. A, 24, 1881, 357, — 109. Th, Wi 
P. A. 62, 1896, 543. — 110. Marey: C. x. 82, 1876, 408. 89, 1879, 203, Jou 
et de physiol. 1877, Nr. 1. Trav. d. Inborat, 2, 1876, 63, — 111, Th. W. Engel: 
59, 1805, 309. — 112. 0. Langendorff: A.P. 1885, 284. A. 61, 189 
113. A. Walther: P. A. 78, 1899, 597. — 114. Rougets 
115. 0. Frank: ZB. 38, 1899, 300. — 116. B. Danilewsky: P. 
117. G. Langendorff: A.P. 1884, ‘Suppl, 1. PA. 57, 1804, 409. 61, 189 
Merunowicz: Uy. B. 27, 187, 252. — 119. M. Lowit: P. A. 23, 1880, ou 
399. — 120, 0, Langendorff: P. A. 61, 1895, 383. — 121. W. Trendelenbur, 
1900, 268, — 122, W. T'rendelenburg: A. P. 1908, 271. — 123. KE. Rohde: 
1906, 104. — 124. Fick: W.B, 1874, 13, Juni. — 125. TA. W. Engelmann 
1875, 465. — 126. R. Marchand: P, A, 16, 1877, 511, 17, 1878, 187. — 127, 
PA. 118, 1906, 111. Die Norven des Herzens Ubersetzt von H, L. Hensner. 
A, Bethe: Allgemeine Anatomie und Physiologie des Nervensystems, Leipzig 
G.E. Nicolai: A.P. 1910, 1. I. Kronecker: C.¥, 24, 1910, 388, — 128. 
dorff: PA. 112, 1906, 522. — 129. Th. W. Engelmann: P. A. 56, 1894, 149. 65 
Das Herx und soine Tiitigkeit im Lichto nenerer Forschung. Festrede. La 
¥ @ Theorie und Innervation des Herzens. Die Deutsche Klinik. Berlin u. 
Gaskell: The contraction of cardiac muscle. Toxt-book of Physiology, 
R.A. Sehilfer. 2, 1900, 169. — 130. W. His jun.; L.A. 18, 1801, 1. Arbe 
mediz. Klinik. Leipzig 1, 1893, 14. — 131. Th. We 
132. L. Krehl u. EB. Rombei A.P.P. 30, 1892, 49. 4 
1805, 139. 72, 1 A.J, Carloon: BoP. 8, 18 
130, A, Beth +: Zwei Reihen physiolo, 
M. Léwit: PA, 28, 1880, 313. — 187. T) 
a 138. WH. Gaskell: Philos. Transact. Roy. Soc. 
Part. 3, 993. - — 139. Th. W. Engelmann: PA. 65, 1897, 131. — 140. H. Ada, 
1905, 1749. PLA. 111, 1906, G07. — 141. G. Ganter a. A. Zahn: O.P. 25, 
PA. 145, 1912, 335. C. PL 27, 1913, 211. A. Zahns OC. P. 26, 1912, 495. PLA 
2 Brandenburg a. P. Hoffman 
1911, 916. — 143. » 120. — 144. HE. Hering 
1910, 4 145. i ne PLA. 154, 1913, 492. — 146. C.J. 
ww. H, Winterborg: P, A. 185, 1910, . 141, 1911, 345. 142, 1911, 461. — 147 
berg: PA. 117, 1907, 228. — 148. L. Haberlandt: Das Horstlimmern. Sa 
I. rast a. Anfsiitze, ‘2H. Heft. Jona 1914, — 149. S, Schnwiclt-Nielaen: A 
lo Physiol. 4, 1907, 417, — 150, H. E. Hering: 0, P, 21, 1907, 719, P. A. 126 
— 151. W. His jnn.: Wien, med, Biitter 1894, Nr. 44. ©. P. 9, 1895, 469, D, 
1899, 329. — 152. H. E. Hering: P. A. 108, 1905, 267. 111, 1906, 298. — 153. 
un. W. Trendelenburg: P. A. 181, 1910, 1. — 154, Eppinger vu. Rothberger : 
1910. — 155. His: CharitéAnnalen. 32, 1909, 3. — 156. Ev. Cyon: Die 
Horzens. Obersetzt von H.L. Hensner. Borlin 1907. J. Dogiel u. K. Ar 
PLA. 113, 1906, 1. J. Dogiel: P. A. 142, 1911, ie Hage 1914, 351. — 157 
PLA. 74, 1899, — 158. Langendor % 1907, 
K. Arehangelsky: P. A. 116, 1907, 482. 160. 3 B. Hofmai 
11. Th. W. Engelmann P. A. 62, 1896, 555. A.P. 1900, 31 
A. A. P. 1846, 483. Wagners Handworterbuch der Physiologie. 3, 2, 
168. Budge: A. A.P. 1846, 295. A. p. H. 5, 1846, 580, — 164. Wo Cui 
JoP. ‘te. 1918, 141. — 165. H. EB. Hering: P. A. 115, 1906, 354. 141, “1 
166. F. Marchand wu. A, W. Meyer: Po A. 145, 1912, 401. — 167. Hofman 
JabrbGeher der gesamten Medizin. 281, 1904, 113. — 168, H. , 
245 0.253. — 169. Th. W. Engelmann: AP. 1900, 315, — 170, LJ. 
PA. 66, 1897, 328. — 171. H. Friedenthal: A. P, 1902, 135. — 172. Lando 
4. Naturforscher-Versamml. Hamburg 1876. — 173. J. B. Haycraft u. R. Kilie 
1891, 426, — 174. D. F. Harris: J.o, P. 82, 1905, 495. 











































































1335) Mer PHUSSEKIIY In eMeMm aUMrEe 


Die Treibiratt eee daher im Vorlanf der Réhre konstant ab, da de 


derselben, die Widerstandshihe, durch die Widerstinde allmihtich me 
Wirme wi wird; am Ende der Réhro bleibt von ihr nur noch die Gesehy 
hohe tibrig, welche die Ausstrmungsgeschwindigkeit bewirkt. 


gecenstellen, bingen ab: — 1. Von der Kohiision der Flissigkeitsteile 
einandor oder der Viscositit der Flissigkeit (Harthle’, Hirsch u. Beck*, Tro 
du Bois-Reymond, Brodie . Miller*, Minzer a. Bloch®, W. “Matter, De 
Wiihrend der Strémung betindet sich die inBerste, wandstiindige Sehieht, welche 
benetst, in volliger Ruhe, Allo ibrigen Plussigkiteschichten, welche man sich vor 


WeRTRR, 
stellt den am schnelisten sich bewegonden Toil dor Fitssigkeit dar. Bei diesem’ 
der aylindrischon Flissigkeitsschichten an ihren Begrengungstlichon miiasen ni 
Fig. 98. aneinanderliegenden } 
teilchen voneinander g 
3. 


. 1 =z: 


den, woftr ein Toil 
kraft verbraucht werd: 
Grobe der Widerstii 
wesentlich ab yonder! 
Kohasionskraft 

sigkeitsteilchen 

der; je inniger die ¥ 
teileben aneinander ba 
grifer werden die \ 
sein und umgekehrt, 
Inicht verstiindlich, da 
stiinde, welche das k 





Bin Druckgefas A mit dem Ausilubrobr a b und eingosoteten me biter 


eee Roe Wasser durch cine 


treiben, Erwilrmung vermindort die Kobiision der Teilchen und daber anch die 
widerstinde. Offenbur maf forner je schneller die Strombewegung vor sie 
heiBt je mehr Flissigkeitstoilchen in einor Zeitoinheit auseinandergorisson wer’ 
grofer auch die Summe der Widerstinde werden. Da die wandstindige, 
benetzonde Flissigkeit sich wihrend der Strimang in absoluter Ruhe befind 
hierans, da8 das Material der Ribrenwandung keinen Finia® anf die Widerstin 
2, Von der Weite dex Rohres. Bei gleicher Stromgeschwindigkeit ist 
der Widorstiinde abbiingig von der Grie des Durchmessers des Rohros; je 
Durchmosser ist, desto griBer sind die Widerstinde. Die Widerstiinde nehmer 
engeron Rohron schnoller a0, als die Durchmesser der Rohre abnehmen. 


Strémung einer Filissigkeit in einem starren, ungleich welten 
Rohren, welche in ihrem Vorlanfo eine angleiche Weite besitzon, ist die Gese 
des Stromes verschieden; slo ist innerhalb der welten Stellen natirlich kleiner 
der engen griBer, Im allgemeinen ist dio Stromgeschwindigkeit innerhalb ung! 
Rohron mngekehrt proportional dem Durchschnitte des betreffenden Ribrenabsch 

Wihrend io Qberall gleichweiten Rihren dio Treibkraft der strimenden 
yon Strecke zu Strecke gleichmiifig abnimmt, nimmt dieselbe innerhalb ungloi 
Rohreo nicht gleichmABig ab. Denn da die Widerstinde in engen Ribren | 
‘als in weiten, so mu8 natiirlich innerhalb der engen Stellen dic Treibkraft stiirker 
als innerhalb der weiten. 

Kritmmungen und Schlingolungen der GofiGe bringen weiterhin 1 
stiinde mit sich: infolge der Zentrifugulkraft presson sich niimlich die Flt 
stirker an der konyexen Seite des Bogens und finden hier somit griBeren Wid 
ihrer Strombewogung als an der konkaven Seite. 











49. Bau und Rigenschatten der Blutgefiibe. 


Die groben Gefiibe dienen im Kérper lediglich als Leitu 

Blutmasse, wiihrend an den diinnwandigen Capillargef 
‘Austansch der Substanzen aus dem Blute zu den Geweben hin v 
kehrt sich vollzieht. 


I. Die Arterien — xeichnen sich den Venen gegentiber ans: durch 
Wandung infolge einer reichlichen Entwicklang maskuléser und olastisch) 
sowie dureh eine stark antwickolte Tunies media bei relatiy dinner T. ady 
Wand der Arterien besteht ans drei Hiinten (Fig. 34), 

1, Die Tunica intima — trigt auf der Innenfliche ein kernbaltiges 
/a) unrogolmaBiger linglicher, platter, nicht goschichtoter Zellen. AuBen vom EB 
‘eine strelfige Bindesubstanz, welche zablreiche spindel- oder stornfirmige Zello 
Fasern, xuweilen auch lingsverlaufende glatte Muskelfasern enthullt. Nach anfen 
die Elastica interna (6), welche bei den feinsten Arterien eine struk 

clastische Haut ist, bei den mittelstarkon als gofensterte Haut anf 
stlrksten sogar in 2—Bfacher Lage faseriger oder gefensterter, olastischor, 
yorvinigter Hinte erscheint. 

2. Die Tunica median — enthilt als am meisten charakteristischen 
glatte Muskelfasern (c). Sie erscheint an den kleinsten Arterion aus qi 

zerstrenten, glatten Muskelfasern gy 

tre wi. feinkorniges, mit wenigen, 

Fasern durchzogenes Gewebe dient" 
dungsmasse. Von den allerkleinsty 
kleinen Arterion fortechreitend, wii 
der glatten Muskeln so vermebrt, 
Gestalt cinor sturk maskulisen | 
schicht anftreten, in welchor die B 
fast vollig xuriicktritt. Die Elastic 
bildet den Abschin8 der Media gogen 
titia hin. — In den grofen Arte: 
die Bindesubstanz sehr erheblich fiber 
scheinon zwischen feinfaserigen Lage: 
(bis 50) konzontrisch geschichtete, d 
atische, gofasorte oder gofens! 
wiegend quorgelagerte Haute, 
liegen nur vereinzelt hier und da wit 
dor Qnere nach, seltener schief= oder Hix 
glntte Mnskelzellon. 

3. Die Tunica adventitia 
den feinsten Arterien eine mit spr 
plasmazellon besetzte, straktarlose Ha 
etwas dickeren erseheint dann cin 
faserigen elastischen Gewebes mit % 
Kren Bindegewebes untermischt (d 
mittelstarken und dicksten Arte 
dio Hanptmasse ans schrig verlanfand 
fach sich durchkrenzendon Bindeln fibri 
gowebos mit Rindegewebszellen, nicht 
Wloinos Artorionsstehon zur Demonstration ™it Fottzellon vermischt. Dazwisehen 
Tee stotnon Schiehten der Robronwandung. mentlich roichlich gegen die Media b 

cides Eadeubel, — (ble slatinche Tsnen- oder gofenstarto asta Lamellen 
Mine Rivonia, ‘finden sich znweilen lingsverlantende, 
fe Dindogemobige Adventiia. elton Blindeln ungeordnete, latte 3 

IL. Die Capillaren, — die sich vielfiltig unter Wahrang ihres Darchm 

und im weiteren Verlanfe wieder zusammentreten, haben sehr verschiedene Dn) 


4 

















Woy a Sen uos rutes 1m GelaBsystem. 


ach Fuchs" sigh i Veonon keine Hrscbsinung: einer tonischen Ere 
Wundsnuskeln; anf clebtrise?? Reiung dar Nerven zeigen nur dio Artorien, nicl 
ane wktive Vorengorung. 

‘LABt man die GefliB© WSgeschnittener lebensfrischer Organe durebstrom 
welchem gewisse Stoffs beige™Mengt sind, so wirken: erweiternd Amylnitrit, 0} 
Morphin, Chinin, Atropin (Harnstof nnd Kochtalz auf die NierengefiiBe), — v 
Adrenalin, Digitalin, Veratrin. 

Auch den Capillaren kommt Contractilitat zu, und 2 
delt es sich nach den Untersuchungen yon Steinach u. Kahy 
nicht, wie man friiher angenommen hatte, nur um eine Vereng 
Lumens infolge einer vergriberten Turgescenz der Zellen der Cap 
sondern um echte Contractilitit. Diese hat ihren Sitz in v 
Zellen, deren Kérper parallel zur Liingsachse des Geftibes stehi 
feine Auslinfer aber senkrecht davon ausstrahlen und die Gefiibe 
artig umklammern, Steinach u. Kahn™ konnten sowobl bei dire 
trischer Reizung. als auch bei Reizang des Sympathicus die Cay 
der Nickhaut des Frosches zur Contraction bringen. 

Die Elastizitiit der Gefiibe ist gering, d.h. sie setzen den d 
Kriiften wie Druck oder Zug einen nur geringen Widerstand 
aber sie ist zugleich vollkommen, d. h. sie kehren nach Aufhéren 
nenden Kriifte in ihre friihere Form wieder zurtick (Muchs**, | 


Pathologisches. Die Arteriosklorose bedingt starke Veriinderunger 
barkeit, Elustizitit und Contractilitit der GofiGwand. 

Eine grofe Kohiisionskraft — ist den Gefiéwandung 
yermége deren sie selbst bei erheblicher Spannung im Innern 
reifung Widerstand zu leisten vermigen. Der Zerreiliungswider 
Venen ist relativ noch grifer als der gleichdicker Arterienwiin 
Gréhant u. Quinquaud* halten die normale Arteria carotis oder 
Menschen einen Druck von 7—8 Atmosphiiren aus, 


50. Die Bewegung des Blutes im Gefiifsysten 


Das System der Blutgefiibe ist nicht allein vollkommen 
angefillt, sondern es ist iberfillt. Das Volumen der gesamten 
ist niimlich grifer als der Hohlraum des Gefiiisystems in leerem 
Darans folgt, dal die Blutmasse auf die Gefiiiwandungen tbe: 
Druck austiben mub, welcher cine entsprechende Dehnung der e 
und contractilen Gefiibwiinde bedingt. Dies gilt jedoch nar wiil 
Lebens; nach dem ode erfolgt eine Erschlaflung der Muskeln d 
und ein Ubertritt yon Blutplasma in die Gewebe, so dab nun d 
teilweise sogar leer angetroffen werden. 

Denkt man sich die Blutmasse im ganzen GefiiBgebiet gl 
yerteilt unter tiberall gleich hohem Drucke, so wiirde sie sich in 
Gleichgewichtslage befinden und in dieser yerharren (wie k 
dem Tode). Wiirde jedoch an einer Stelle des Rihrengebietes di 
unter welchem das Blut steht, erhiht, so wtirde es von der ¢ 
hwheren Druckes dorthin ausweichen, wo der geringere Druck 
es wiirde eine strémende Bewegung der Blutfliissigkeit entste| 
derartige Druckdifferenz unterhiilt wihrend des Lebens dau 
Herz, indem es mit jeder Systole der Kammern eine gewisse Mi) 
in die Wurzeln der groben Arterien wirft, die unmittelbar znvor 4 


saa] A wasvewegmng. 


In den Capillargefaben hért die pulsatorische Druckse 
und die pulsatorische Beschleunigung der Strombewegung anf; 
ares ibeanaisriche: Girma beyseung tibrig. Die bedeatend 

, welche sich der Strombewegung gegen das Capillargebiy 
bieten, lassen allmiihlich beide orldschen. Nur wenn die 
sehr erweitert werden und der Druck im arteriellen Gebiete zunin 
die Pulsbewegung und die pulsatorische Beschleunigung der Strom 
durch die Capillaren hindurch bis in die Vacant sich fort: 
So sieht man es an den Geftiben der Speicheldriisen nach Re 
N. facialis, welcher die Gefibbahnen erweitert (vgl. § 99). Umse 
einen Finger mit einer elastisehen Sehnur, welche den Rtic 
Venenblutes erschwert und den arteriellen Druck unter Erweii 
Capillaren des Fingers erhéht, so sieht man isochron mit dem 
Klopfenden Gefithl die geschwellte Haut sich intermittierend stiii 
Capillarpuls* (Glaessner '%), 

Fine vollkommene schematische Nachbildung des Kreislaufes ist von 1 
sirniert worden. 


Im folgenden werden hintereinander die Pulsbewegung 
eraraek: — die Geschwindigkeit der Blutbewegung al 
werden. 


51. Pulsbewegung.” — Technik der Pulsuntersuc 


Tm Altertum warde yon den Arzten mehr dem krankhaft erregten a 
maten Pulso die Aufmerksamkeit xngewandt. So spricht Hippokrates (460— 
nur von ersterem und bezoichnet ihn mit dem Ausdruck cpuyuds. Erat sp 
namentlich yon Herophitus (300 y, Obr,), der normale Pals (465) dom kravkt 
gogentibergestollt, Dieser Forscher logto fernor besonderes Gewicht auf die Ze 
nisse der Dilatation and Contraction des Artorienrohres, auch bestimmte er 
Figenschaften der GriBe, dor Fille, der Oeloritat (agvyuos txyuz) und der 
(epeypos xuxvéc). Sein alexandrinischer Kollege Krasietratue (am 300 y. Chr.) 
fiber die Fortpflanzung dor Pulswellen richtige Angaben gemacht, inc 
driicklich sagt, duB der Puls in den dem Herzen nitherliegenden Schlagudern frt 
ala in den entfernteron (3 54). Erasistratus fihite ferner auch den Puls unt 
ia der Kontinnitét ciner Schlagader eingeschalteten Kanlile. Archigenes hat \ 
tischen Pulse seinen Namen gegeben, den er in fieberhaften Krankheiten xt 
Gologenheit hatte. Galenne (130—200 n. Chr.) stellte genaner als seine Vo 
Dehnungs- und Contractionsverhiiltnisse der Schlagader wilhrend der Palsbew 
namentlich orklirte er den Pnisns tardus dadarch, daS das Moment der Ausd 
Vingert sei. Auch fiber den Polsrhythmus, ferner Gber den Kintla8 des Temper 
Guschlechtes, des Alters, der Jahreszeiten, des Klimas, des Sehlafens and des V 
Gemitsbowegungen, der kalten und warmen Bilder finden wir bei Galenus be: 
Mitteilungen. — Cusanus (1450) 2ibite auerst die Pulsschiiige nach einer We 


Die Pulsbewegung kann an verschiedenen Arterien gese 
mit den Fingern gefitihlt werden; am haufigsten geschieht dir 
Art. radialis oberhalb des Handgelenkes. Fiir eine genauere Ei 
der dabei stattfindenden Bewegungsvorgiinge ist jedoch die gri 
Registrierung des Pulses: Sphygmographie notwendig. (Erst 
mograph von C. Vierordt®*, 1854.) Die Pulsbewegang wird dabei! 
auf cine Pelotte, die der pulsierenden Stelle nach Art des pal 
Fingers angedriickt wird, und weiterhin auf einen Hebel tiberts 
die Bewegung in vergribertem Mabe wiedergibt, Die Spitze d 
(Schreibhebel) zeichnet endlich die Bewegung in Gestalt eit 
auf einem berubten Stick Papier auf, welches durch ein Ul 
gleichmiibiger Geschwindigkeit an der Spitze entlang bewegt wi 


Landols-Rosomans, Physiologic. 14. Aufl. 








erty ‘Technik der Pulsunters 


wm dionen dazn, den Apparat anf der Umgebu 
Dic Metallschiisselehen S ‘8’ gehen nach oben i 
Gwaumischliuche A und A’ mit ontsprechend einge 
werbunden, die in umgekehrter Stollang, mit dor Gumn 
Defestigt sind. In der Mitte der Gummimembran ragt 
sam dem Sebreibhebel Z and Z naho an seiner Ache 
Gummimembran, welche durch die pulsierende Stelle b 
der Motallschiseelchen und der Schliiuche auf die ¢ 
‘oberen Schroibbebel fbertragen, 
Es sind cine groBe Zahl von Modifikationen de 
(s0 von ©. Frey**, Jaquet*® a. a.). Rine besonders bh 
Kebranchte Form ist der Dudgeonsche™ Sphygmogrs 
die der Polotte P (Fig. 39) nacheinander 
seblieBlich auf die Schreibnadel # Qbertragen, die di 
xeichnot; das Gegengewicht g hiilt die einzelnen Teile 


Von einem idealen Sphygmographen n 
wegung des Schreibhebels und somit die 
wegung der pulsierenden Stelle absolut g 





Duilgeons Sphyemograph, Die Chortrag 


derung erfiillen jedoch die meisten Instru 
durch im Apparat liegende Fehler wird d 
pulsierenden Stelle in stark entstellter I 
Petter** haben die fir die Konstruktion de 
kommenden Momente einer theoretischen und 
unterzogen, auf die hier nur yerwiesen 
Grand ihrer Untersuchungen einen neuen Sp 
nach ihren Angaben alle Pulsformen, w 
Menschen vorkommen, getreu aufzeic 





52. Die Pulskurve, das Sphygmogramm. 


An der Pulskurve (Fig. 42) erkennt man den wiihrend 
dehnung der Arterie verzeichneten aufsteigenden Schenk 
Gipfel — und den der Zusammenziehung der Arterie ents} 








Pig. 42. 





schon 


absteigenden Schenkel. Zackenartige Erhebungen, welche 
absteigenden Schenkel findet, nennt man katakrote Erhebur 
im aufsteigenden anakrote Erhebungen (Landvis?*). Am aut 
Schenkel sind gewbhnlich keine Besonderheiten wahrnchmbar, « 





53. Qualitiiten des Pulses. 


1. Die Pulsfrequenz. Dio Zah! der Palsschlige in einer Minuto heiBt 
tam unterscheidet danach den Pulsns frequons ot rarus, Der normale rv 
lsat 71—72 Pulsschliige in einer Minute, das Weib gegen 80 Sehliige, Doch 1 
frequenx von sebr vielon Momenten besinflubt: 

a) Das Lebensalter. Die Pulsfroquenx betriigt belm Nengeborenen } 
ersten Lebensjahre 120—130, sie sinkt dann mit xanehmendem Alter, betrigt 
sngefihr 90, vom 10.—15. Jahre 78 und bis zum 50. Jahre etwa 70, im 4 
steigt sie wieder etwas an bis anf 80 und dariber. — rv. Lhota* zeigte, daB b 
Handew die Abnahme der Pulsfrequenz vor allom durch das Anftreten und d 
Verstiirkung des Vagustonus (§ 280) bedingt wird. 

b) Die Kirperlinge: anter sonst gleichen Verhilltnisten nimmt die 
mit xunohmender Kiirperlings ab. 

c) Sonstigo Kinfliisse: Der Pala ist im Steben etwas freqnenter | 
und im Sitzon wieder etwas frequenter als im Liegon (Geigel®™), Maskeltitiggh+ 
ber das Zustandekommen dieses Kinflusses vgl. § 74. 3, Aulo®, Mansfeld* 
rung des arteriollen Blutdruckes, — Nahrungsanfnahme, erhihte Temperatur, 
Schmerz, — Chelkeit, — psychischo und geschlechtliche Erregungen beschleun) 
—~ Im Wochenbett, im Hungeraustande ist die Pulsfrequenz herabgesetat. 

d) Im Lanfe eines Tuges zeigt sich eine Poriodixitat der Puls, 
Schwankungen folgen dem Verlaufe der Temperaturkurve. 


Pathologisehes. Unter krankhaften Verhiltnissen ist die Palsfroque 
Andert; im Fieber kann sie auf 120 und darfiber steigen, Periodische An} 
steigerter Pulsfrequens (bia xn 250) werden als Pyknokardie (falsch ist di 
Tachykardie, da 727%: = coler ist, & unten), abnorme Verlangsainnng bis auf 1 
als Spanikardio (falsch ist die Bezeichnung Bradykardio, da fp; —tardus 
not. In Piillen, in denon dio Pulsfroquenz auf 24, 16, sogar 13 herabgosetzt wa 
wohl das Allgomoinbetinden wonig gestort (Frey*, Beleki™®), 

Pulsfrequenz einiger Tiere: — Elefant 28, — odler Hongst geg 
nn Arbeitspferde etwas mehr), — Rind gegen 50, — Schaf, Schwein 75, — 
Kates 130, — Kaninchen 120—150, — Maus 520—675 (Buchanan™) in 1} 




















2. Pulsus celer ot tardus. Vou der Pnisfreqneng streng xn unterse 
Pulsceleritat, Bin Putens color cder schnollendor Pals ist ein sole 
rasch entwickelt und wieder vergeht, rasch an- and abstelgt; beim entgegen; 
alten, wenn die Dehnung des Arterienrohres durch die Pulawelle und das 21 
langsam erfolgt, spricht man von Pulens tardus odor gedohntem Puts, Ki 
oktion, hohe Nachgiebigkeit der Arterionmembran, leichtor Abflu® dos Blutes, 
der pulsierenden Stelle am Herzen heginstigen die Rntwicklung eines Pulsus ¢ 
gesprochen celer ist dor Pols bei Aorteningnffiziens, 


3, Nach der Grife des Pulses, dh. nach der Weite der Exkursion, diy 
wand bei jedem Pulsachlag macht, unterscheidet man den Pulans magnui 
Ist die Gride verschiedenor Pulse nicht anter sich gleich, wie normal, so spi 
Patsus inanqualia, 


4. Unter Spannung oder Hiirte des Pulses (Pulgns durns ot mo 
man dus Mai von Kraft, welches man anfwonden mnB, um die Arterie vollat! 
primieren, so da8 poriphor von der komprimierten Artorie kein Puls mehr 
die Spannung des Pulsos ist danach ubbiingig von dom maximalon, auf dor I 
welle in der Arterie vorbandenen Blutdrack. — Streng zu unterschoiden yor 
des Pulses ist die Beschatfenhoit dor Artorienwand, die selbst hart (x. T 
skleroge) oder weich, elastisch (beim Gesunden) sein kann, 


5. Rhythmus des Pulses, An dem normalen Pulse erkennt der tastende 
hesonderen Rhythmus, sondern es folgt Schlag anf Schlag in anscheinend gle 
wenn anch goringe xeitliche Abweichungen der Pulse untereinander oft yorkommn 

fish", Janowski*), Zawoilen fillt in der normalen Rethe plitalich oh 
aussetzender Puls. Rohrt das Auasetzen von ciner bloben Schwiicho der S 
hoift der Pals P. intermittens, — ribrt es yon einem Ausfall dor Systole 
man ibn P. deficions. Mitunter erscheint in einer normalen Reihe ein Pulse 
geschoben: Pulsns intercurrens. Dor regelmifige Wechsel von cinom hoh 
niedrigen Polse wird als Polsus alternons bezeichnot, Bolm Pulsas bige 
die Palse panrweise auf, so dal der xweite Schlag dicht hinter dem ersten folg 





tiene 
{8554 * Venenpais. Das! Phlebogramm. 


— Bei 4, 
Pathologisehes: 
windigkeit der der rele cz erhoht ee cay Mie und Night tt ist die Fortptlana 


seh 

ine (Aneuryame) iat Yaa Verlane sa saan der ate der Welle xur Folge, abnlii 
Eerschlat hoben Fi Biutleer 

Wotunnhrerieesaet eee eS 


55. Der Venenpuls. Das Phlebogramm. 


Methode, — Man kann von den Bewogangen einer Vane amittelst empiir 
Sphygmographen eine Kurve verzeichnen: die Venenpulskurve oder das Phiebog 
Zur Dentang derselben ist die gleichzeitign Registrierung des Kardiogramms oder 
mogtamme erforderlich, — Volhard™ iibertriigt, um das geltliche Verhiiltnis 2 
Venen- und Carotispuls zn demonstrieren, die Pulshewegungen yermittelst zweler 
Glastrichter, din anf die pulsierende Venn und die Oarotis anfgesutet werden, at 
nebensinanderstebende Wassermanometer mit gofirbter Fiissigkeit. 

Unter normalen Verhiltnissen erlischt im allgemeinen die pv 
risehe Bewegung im Capillargebiet; in den Venen findet nur noe 

leichmiibiges Strémen des Blutes statt (5.145). Hiiufig beobachtet 
jedoch unter physiologischen Verhiltnissen in der Vena jugularis com 
eine Pulsation; sie erstreckt sich entweder nur anf den unteren Te 
Vene, den sogenannten Bulbus, oder auch hiher hinauf auf den $ 
der Vene selbst. — Die Venenpulswelle pflanzt sich langsamer fo 
die Arterienpulswelle, nimlich nur 1-3 m in 1 Sekunde (Morrow %* 

Darch die Venonklappon oberhalh des Balbus wird die Erscheinung des 
logiscben Venenpnises nicht boeintuBt, da ox sich dabei um eine negative Wellenbe 
handelt, die in der Richtung dos Blutstromos verliuft (s. unten); beim pathologischen 
pals sind dio Venenklappon oft insnffizient, 

Bei dem physiologischen Venenpuls handelt es sich nicht etw 
eine yon Herzen in die Venen zurtickgeworfene Welle, sondern der g 
wibige Abflui des Venenblutes wird durch die Herztiitigkeit bald begih 
bald behindert. Die normale Venenpulskurve zeigt drei Hauptw 
Die erste Erhebung, die mit der Systole des Vorhofes (der Diastol 
Kammer) zusammenfillt, daher mit der Erhebung des Carotispulses 
niert, wird bewirkt durch die Beeintrichtigung, die der Abflub des V 
Diutes im Moment der Vorhofseontraction erfihrt. Die zweite Erh 
der Venenpulskurve fullt annithernd mit der Erhebung des Carotis) 
gusammen, es handelt sich dabei teilweise um eine von der benach! 
Csrotis tibertragene Bewegung, zum Teil um eine Abflubbehinderun 
YVenenblutes zur Zeit der Ventrikelsystole und des Trieuspidalkla 
schlusses. Die dritte Erhebnng endlich fillt zusammen mit dem B 
der Kammerdiastole; wie sie zustande kommt, ist anklar, Ober 
gehen die Ansichten tiber die Deutung der Venenpulskurve noch 
einander (vgl. Hering», Wenckebach *, Frédericg®", Rihl°*, Edens * 

Pathologisches, — Der pathologische Venenpals findet sich bei 
spidalinsuffiziens; or fallt (im Gogensatz zum normalen) zeitlich mit der Kj 

zusammen. Rr wird dadarch bewirkt, da6 der rochte Ventrikel bei seiner Con! 
‘Blut darch die nicht schinBfihige Kioppe in den Vorhof nnd von da in die Venen 
wirft Pilanzt sich die Puisation in die untero Hohlyene ond deron Aste fort, so ¢ 

mte Lebervenenpuls. 

Zoweilen kommt es yor, da der Puls in den Capillaren nicht erliseht, sonde 
durch das Capillargobict bis in die Venen fortptlanzt, sogenannter penetrisrender \ 
pels: so 2. B. wenn die Arterien stark erweitert sind (vgl. 8 oder wenn der 
for Aenselven stark ansteigt und schnell wieder wbfillt, wie bei jen der Aortenk 

Untorscheidung der verschiedenen Arten des Venenpulses, — 

jext man die pulsierende Vene, so hirt beim physiologischen Venenpols die Pi 
Pe eripheren Stick der Vene auf, im zentralen Wloibt sie meist schwicher bosteh 









18a, 42007 Feltee atantorische Brvebelnmngen. 


Wutimekes bewirket hydrostatisch wirkende Lageveriinder 
weitrangen oder VereOzerangen anderer griberer GeftiGpr 
‘dD. Rewegung der MuSkulatur der eingebrachten Extremi 
Nolwwsabnahme (Mranc. Glissons Versuch, 1677), da der Ven 
sebleunigt ist (§ 64), — Wenn auch die intramuskuliiren Gefil 
werden. — 6. Hohe (83—36°C) und niedere Temperature) 
auf die Armhaut appliziert, vermehren das Volumen des Ar 
einer durch die thermischen Reize bewirkten Parese der Gefii 
‘Moxso"). — 7, Geistige Anstrengung vermindert das V 
‘tremitiit (Mosso®), ebenso der Schlaf. — 8. Reizang der } 
hat Abnahme, die der Vasodilatatoren Zunahme des Volumen: 


! 57. Anderweitige pulsatorische Erscheinung 


1. Mundhoblen- und Nasenhdhlenpuls; Trommelfollpal, 
gofiilite Mund- und Nasenhoble zeigen bei goseblossoner Glottis dadurch, di 
adern ihrer Weichteile pulsieren, ebenfalls in ihrer Luftmasse eine pulsatoris 
die mit Hilfe emptindlicher Registrieryorrichtungen anfgeschrieben werden ka 
syatelische Schwellung der blatreichen Weichteile der Paukenhihle kan 

eise vine Palsation am intakten ‘Trommelfolle beobachtet werden oder an S 

die etwa 2ufillig innerhalb der Offaung eines krankhaft perforierten ‘Tromme 
‘seeetzt haben, 

2 Bei lebhafter Anstrengung erscheint hiinfig mit jedem Palssch) 

tom Gesichtsfelde eine pulsatorische Erhellung, — bei erh 

eine analoge Verdunkinng. — Mit dem Augenspiegel erkennt man mitun 

der Rotinaartorien, die namentlich bei Inanftizienz der Aortaklappen bedeutn 

3. Der Musculus orbiewlaris palpebrarnm zuckt anter jhn 
nisson aynebron mit dem Pulse; es rihrt diese Zuckung, wie es scheint, ¢ 
a Pulanch az ihn dureh die sensiblen Nerven reflektorisch xn einer Cont 

ie). 


4, Sitst man mit Gbereinander gexchlagenen Beinen, #0 erkennt 
schwebenden Unterschenkel Pulssehlag und RiickstoBelevation. 


5. Dem Gehirne wird durch die grofien an der Basis verloufenden 
‘pulsstorische Bewegung mitgeteilt. 
6. Onychographic von Herz, Setzt mun einon émpfindlichen P 
einen Fingernagel, so erkennt man die Pulswellen in den kleinen Geftifen dev 
Sind die Gefibe der Fingorbocre contrabiert, 40 erlischt die Pulsation. Das Ox 
t ‘erseheint als eine Kombination von Sphygmogramm und Plethysmogramm (A 
! 7. Kine pathologische Erscheinung sind die systolischen 
din Bpigastrinm, tells bervorgerafen vom Herzen bei Hypertrophie det 
linken Ventrikels boi Tiefstand des Zwerchfells, toile durch starkes Pali 
erwelterten Abdominalaorta oder der Art, coelinca. — Abnorme Keweiter! 
rysmen) dor Schlagadern lassen anch an anderen Stellen eine abnorme Puls; 
x. Bean der Trachea darch das Aneuryama der Aorta ascendens ond tranave 
Hypertrophie und Dilatation dos linken Ventrikels bewirh 
tion der dem Herzen xuniichst liegenden Arterion; bei dem analogen Zastande 
Kammer pulsiert sicht- und flhibar stirker dio Pulmonalis im 2. linken 1 
‘Wenn bei gut ansgeglichener Aorteninsuftizionz kriftiger Kranker die Milz ( 
serhwellt und fliblbar ist, so pulsiert sie obenfiulls (auch om Penis ist Puls 
fel Morbux Basedowii kann sie monatelang pulsieren. 


48. Der Blutdruck. — Methoden der Messung des a 
Blutdruckes, 


Bei Tieren, — 1. Stephan Hales® band auerst (1727) in dio Se 

Zine lange Glasrohre oin und bestimmte den Blutdruck durch Mor 

ey gotiule, bis au wolcher das Blut in dieser Rare sonkrocht emporsteig 

Bate 2 (Quocksilbermanometer, — Poisewille® verwandte (1828) 

uy Zesilber geflllte Munometorrihre, die seitlich durch ein starres. 
aque 

















1898) sietnol™ HF Messing des acteriellon Blutdeuckes, 


anBoo darch eine Stabliedet "© Petotty fot aufgedriickt, das andere Ende 
featgektommt, darch cite S06 a Kony die Spamnung der Feder verinder 


Hig. 8, 





Federmanometor nach Fronk- Fetter. 


‘den durch einen besonders konstralerten Hebel ar 





Bowegungen der Feder 
spitze fbertragen. Um die Schwingnngen xu dimpfen, kann in die Manome 
Seheibe / mit einer feinen konischen (itnung elngosetzt werden. Diesos Instru 
Frank allen bisher konstruierten Manometern an Giite weit Uberlegen. 


Pig. 46, 





Winkdruckmessung nach v, Heeklnghawren. 


B. Beim Menschen" — kann man den Blutdrack in den Arterien 
destimmen, da man mit einem hieran gecigneton Apparat cinon ullmithlich 
Drock anf eine Arterie wirken LiGt und untersncht, bei welchem Drnck in) 
dor Pals varschwindet. Das erste nach diesem Prinzip hergestellte, praktisct 





(s59) Der Blataruek in den Arterien, 


Di pulsatorisehe Eri I NeShute botrug 17—20mm (veel. Blau 
arder Hadise al eine Wrwachsenen fund v. Basch® ee remo 

x ‘Temporalis superticialis 80-110 wm ie, Sirah 
fand bei normalen jingeF” Mnnorn in der Rube (mit dom Apparat von Rina-Hto 
maximalon Blutdrnck 21 90-125, don ininimalen 2u 63—95 aun Hg. (Vel. anton di 
von 6, Recklinghausen.) 


Bei Kindern — nimmt mit dem Alter, der GréBe und dem Gewieh 
Biatdruck zu (Tavastjerne™, Wolfensohn-Kriss"), 

Nougeborenen noch yor Beginn der Atmung fand Ribemont™ den Bh 
in oiner Arteria umbilicalis = 64 mm Hg, Seitz'° fand 73 mm Hg. 

Nach Volkmann*' botriigt in der Carotia der Druck beim Pferd 122 bis 2 
beim Hund 104—172 mm, boi der Ziego 118—135 mm, beim Kaninchon 0 mm, bein 
SS—17i mm, in der Kiemenarterie beim Hecht 35—Simm Hg. Fraenkel®” far 
mittleren Blntdruck beim Kaninchen au 122, beim Hand zn 180mm Hg; bel Kat 
150 mm Hg, die pulsatorische Schwankung variierend von 43—64 nm Hg. Beim Rin 
Brenner’? als normalen Wert des Blutdrucks 218 mm Hg. Bei Vogeln ist der Bh 
bedentend buhor als bei den Siugeticren; or kann fiber 200 mm Hg botragen (Stitbe 
der Art. cruralis des Froschos ist der Minimaldrauck 41, der Maximaldruck 52 om Hg 
meister”, Pr. N. Schulz”), 

Tm allgemeinen ist der Blutdruck bei groBeren Tieren hdher als bei kle 
‘woil bei jenen wegen der erheblicheren Linge der Blutbahnen groBere Widerstinde 2 
winden sind, Sehr junge nnd sehr alte Tiere haben niedrigeron Drack als Indi 
anf der Hohe der Lobensfunktionen, 

Der arterielle Drock bei Foten — ist niedriger als bei Nengeborenen, der 
Druck ist Jodoch bedoutender, Bei einem nicht ansgetragenen Schaffiitna war der 
46mm, beim fast relfon Schafe 84mm. Man fand die fitale Drackdifferon zy 
Str veniisem Blute kaum halb so gro® wie beim erwachsenen Tiere (CoA 
n, Zunts™ 


Innerhalb der grofen Arterienstiimme nimmt der Blutdruck ; 
die Peripherie hin nur relativ wenig ab, weil die Widerstiinde in 
groBen Rohren nur unerheblich sind, Nach FB. Weber ist der Dru 
der Carotis nur 3,5 mm Hg hoher als in der Cruralis. Sobald jedoc 
Schlagadern unter vielfacher Teilung cine erhebliche Verjiingang des Lu 
ciciag nimmt in ihnen infolge der erheblichen Widerstiinde der Blut 
stark ab. 


Einflisse auf die Hthe des Blutdruckes in den Arte 

Der Blutdruck in den Arterien hingt ab: 1. von der Fiillung der Gi 

- der Blutmenge; 2. yon der Herztiitigkeit; 3. von den im Gettiisystem 
handenen Widerstiinden. 


! 1. EinfluS dor GofiBfallung. Man solite erwarteo, daB boi Vollblitigen, 
Vermohrang der Blutmasso durch ‘Tranfusion, anch nach reichlicher Nahrungsauf 
dor Blutdrock erhiht, bei Blotarmen, nach profasen Blutverlnsten oder nach bodeute: 
Avsgaben aus dem Blute (zB. durch starke Schweife, kopidien Durchfall) dageg: 
niedrigt sei. Keineswegs findert sich jedoch der Blutdruck mit der Vermehrung un 
mindorung des Blutes in geradem Verhiiltnis. Dus GefiOsystem besitat vielmehr ve 
woer Muskeln die Fithigkeit, sich dem griBeren oder geringeren Blutvolumen inn 
womlich weiter Grenzen anzupassen. Daber steigt bei miGiger Blutvermehrang der 
drook xunichst noch nicht (Worm-Maller™) (§ 35, 1). Der Umstand, da + 
Fidstigkeit ans dem Blute in die Gewebe transandiert, wirkt fiir das Konstantbleib) 
Diutdruckes mit (v. Regéczy '*), — Auch miifige Aderlasae (beim Hund bis xa 2,8) 
‘ichtes) haben noch keinen nennenswerten Abfall des Blutdruckes eur 
mes 2), nach kleinen Blutverlusten kann or sogar stelgen (Worm-Maller™). Roic 
Mutentziehnngen bringen jadoch ain starkes Sinken des Blutdruckes hervor, solche yon 
6%, des Kirporgewichtes machen ihn = 0. 


2. Einflu® der Herztitigkeit. Die Hohe des Blutdruckes | 

ab von der Frequenz und der Stiirke der Hersschlige. Beide Fak 

musammen die Grébe der in der Zeiteinheit in das Gefiilisy 
getriebenen Blutmenge und dadurch den Blutdruck. 





— 
‘[$ 60.) Der Blutdruck in den Arterien and Capillaren, 


Beim Menschen fand ?. Recklinghausen™ x. B. bei Mossung am Oberarm 
Werte fir den maximalen, minimalen Pulsdruck und die Palsdruckamplitade: 158, 
— 145, 88, 57 cm Wasser, 

Harthle™ fond beim Kaninchen den pulsatorischen Drackzuwachs fast gleich 
Drurkes withrend der Pulspause; e, Horn” gleich */, dos maximalen Blutdruckes. 

Der Ablanf der pulsatorischen Druckschwankang wird im allgemeinen von 
woholichen elastisehen Manomotern keineswegs gotren wiedergygeben, sondern mit mi 
weniger groen Entstellungen, Cher den wahren Verlauf der Drackschwankungen 
Aorta tnd in den peripheren Gefen rel Frank, 

2. Die respiratorischen Druckschwankungen. Der Drack 
Arterien erleidet durch die Atembewegungen regelmiibige Schwanke 
und zwar in der Art, da bei jeder stirkeren Inspiration der Druck 
bei jeder Exspiration steigt. Diese Schwankungen erkliiren  siel 
nichst rein mechanisch daraus, dab mit jeder Exspiration das B 
der Aorta den Druckzuwachs durch die komprimierte Luft im Thor 
fihrt, bei jeder Inspiration dagegen die Druckabnahme durch di 
die Aorta wirkende Verdtinnung der Luft in den Lungen. Auferdem 
riert die inspiratorische Thoraxerweiterung das Blut der Hoblvener 
Herzen, die Exspiration staut es an und wirkt so auch auf den Blut 
Die Schwankungen sind am ausgesprochensten in den dem Thorax 
liegenden Arterien (vgl. Avonecker u. Heinricius ''*). 

Zam Teil aber rithren die respiratorischen Blutdruckschwank 
her von neryésen Einfliissen, niimlich yon einer mit der rhythmische 
regung des Atemcentrums parallel gehenden Erregungsschwankung des 
motorischen Centrums, wodureh sich, jeder Anregung entsprechend 
Arterien contrahieren und so den arteriellen Druck steigern (,,7'rau 
Heringsche “* Drackschwankungen*), Diese Schwankungen treten bes 
dann deutlich in die Erscheinung, wenn bei einem curarisierten, also 
mehr selbstindig atmenden und daher ktinstlich geatmeten Tiere die | 
liche Atmung ausgesetzt oder ungentigend ausgefiihrt wird; durch d 
nehmende Venositiit des Blutes wird das vasomotoriseche Centram 
gereizt, der Blutdruck steigt an, die Blutdruckkurve zeigt deutlic 
thythmischen Schwankungen. 

Unter bosonderen Versuchsbedingungen lassen sich noch verschiedeno andere 
hedingte regelmiBige Schwankungen dor Rlutdruckkurve beobachten, So konnen dure 
tragung der Impulse vor Atemeentrum auf das Vaguscontrum Verinderungan de 
froquonz und dadurch Anderungen dos Blutdruckes vorursacht worden (Fredericg 
3. Mayer ™® heobachteto Blutdruckschwankungen, hei denon zahlroicho Respirationen 
Blntdrackwelle entsprochen; das Zustandekommen derselben ist noch nicht vollig ki 
Endlich kiinnen Reflexe durch die Atembewegungen von den Lungen her Blntdrucks 
Kungen horvorrufen: pulmonale Reflexwollon (Morawitz"). 


60. Der Blutdruck in den Capillaren und Venen. 


Bostimmung des Blatdruckos in don Capillaron, — Legt man ein Glasp| 
von bekanater GriGe anf dio gefiBhaltige Unterlage und belastet os in passonder W 
lange, bis die Capiliaron znorst erblussen, so findet man annithornd den Druck, welcl 
Blutdruck dieses Capillargebietes gorade fiberwindet. Man orhilt den Druck (ausg 
in Zentimeter Wassorsiule}, wenn man die Zahl fir das drickonde Gewicht (Gev 
Gewicht des Glasplittchens) durch die Zahl flir die Druekfliche (angegobon in Q 
aentimetern) dividiert (N.r. Kries™, Lombard™®), Pir die Capillaren des Fing 
erhobener Hund betrigt der Drick 24mm Hg, — dor gesenkten Hund 62 nun, — a 
2mm, — am Zabnileisch des Kaninchens 82 mm, — rc. Recklinghausen 9 tibt 

eines gelochten Gammibeutels, der mit der Pumpe aufgeblasen werden kann und 2 
die au untersuchende Haut and eine Glasplatte 2v liegen kommt, einen zunehmende 


wey “een Windigkelt des Isutstrunies, 


B : 
— Gor Kngenpparst 42 um seine Achso xy gedrebt, so da nnn B an 
Kommt, So wiederholt lait tie Erscheinung, und die Beobachtung kann oft lang 
werden. Aus der beobachteten Zeit, wolche sur Pillung der einen Kogel dur 
strémende Blut notwendig ist, berechnet sich dio anf die Zeiteinhelt entfallende 


3. C. Vierords'*” Himotachometer (1858) — miBt die Schnolligke 
stromes durch eine dem Hitelweinachen .Stromauadranten* nachgebildets * 


Fig. a7. 









































A Votkmanne Mamodromometer, — 1 Ludwigs Stromabr, 


Kin in einer strimenden Fiissigkeit niederbiingendes Pendel wird yon dieser 
und zwar um go stirker, je grifer die Stromgeschwindigkeit ist. — Der Ay 
vin Metallkfistehen (Fig. 48, I, 4) mit planparallelen Glaswiinden dar, welehes 
schinalon Seiten xum Rin- und Ausstriémen des Blutes 2 Kanilen (e, @) besitat. 
hangt dem ceintretonden Blutstrams gegeniibor ein Pendelehen (p), dessen an 
skal abzulesender Ausschlag mit der Schnelligkeit des Stromes wichst. Dor A) 
yorker emplrisch geaicht. 








Die g 
{s62] Joschwindigkeit des Blutstromes. 
» gibt ei 
Die Figur © F'Staiqu®, Nachbildung der Kurvon aus der A. ex 
Die Sebnelligkelt det sch bei ‘Me betrag in dem Moments 1,—1 = 238 
2, —2 = 225 mm, endlin Yel 8,3 
6. Aus dor pléthysmographischon Kurve (vg $56) Ja 
schwindigkeitskuryo gewitlnen. —Hje Anderungen im Volumen dor =a 
zm 





177 mm, 


mOssen offenbar um 80 Schneller erfolgen, je schneller das Bint in dea 
strimt: man kann daher aus der plothysmographischen Kurve die Ge 
Karve konstruicron (Fick**). rv. Kricy™* hat die Geschwindigkeitskurve 
Plethysmographen gewonnen. Er yerband den Hoblraum des Plothyxmogrd 
Schlauch mit einer Gasflamme; wird das Volumen dos eingeschlossenen 
schielt die Gastlamme sofort empor, wm sich dann wieder auf ihre fr 
stellen, Die Hohe, bis an welcher die Gasflammo emporschieBt, hingt von] 
koit des Blutstromes in 
Gtiedes ab, Die Schwank| 
werden auf lichtempfindl] 
L ches sich anf einem ro 
is betindet, photographiert; ( 
hoit Tachogramm; sid 
pulse (vgl. Frank" ), 


Von dem Stan 
an vergriBert sich 
Gebiet stetig durch 
der Aste, so daB in 
auflisung sich der 
Strombettes bis 2 
und dartiber erwei 
hier aus wird du 
der yeniisen Stiimr 
schnitt wieder eng 
dennoch weiter als 
Anfang. 











Ausnahmen macht 
communes, welche xusa 
als der Stamm der Aorta 
Querschnitte der vier 
zusammen enger als der 
monalis, 

Durch einen 
schnitt des Kreisla 
groben wie des klei) 
eine gleich grobi 
verschieben. So m 

[. Schema dos Photohimotachomotors von Cybutax. — “ie Aorta und Palmo 
TL. Pilots Bobro. sehr ungleichen Dru 
($61) die gleiche Bla 

Die Geschwindigkeit der Strombewegung mub sii 
einzelnen Stellen des gesamten Strombettes umgekehrt verh 
{Querschnitt des Strombettes. Es nimmt daher die Stromgeschy 
der Wurzel der Aorta und Pulmonalis bis zu den Capills 
hedeutend ab, so daf sie in denen der Siiuger nur noch 0, 
Sekunde (beim Frosche 0,53 mam) betriigt, beim Menschen 
(0. Vierordt**), Nach A, W. Volkmann®™ fliebt das Blut 
laren bei Siiugern 500mal Jangsamer als in der Aorta. Ir 
stimmen — wird der Strom wiederum beschleunigt, e 
den gréferen noch 0,5—0,75mal geringer als in den zugehi 














1308) smuwewugumg on wen yen 


Kann dshor nur AubcbIu8 £oben ther dio ktirzeste Zeit, in darein Partikelc 

dom ginatigeton Verntltnissen die ganze Kreishmfbahn dureheilon kann (vgl. r- 

Auf die Zoit fir den Umlant der ganzen Blntmasse ermoglicht slo dagen 
, diese ish unzweifelhatt gréfer. 

Nach einer anderen Methode hat Stewart ™ goarbeitet, Bestimmt man galvan 
zuniichst an ciner uneroffneten Ader den elektrischen Widerstand nnd injiziert nun 
markierten Momente etwas Kocbsalziosung in die Blntbahn, so wird, wenn das s 
Bint dic zum Gnlvanomoter abgeleitete Strecke paxsiert, der galvanische Wider 
nehmen; dieser Moment wird gleichfalls markiert, 

So fand Stewart fir den kleinen Kreislauf etwa ', der gesamten Kre 
=10A Sckunden; Kaninchen, Hund), Ex betrug ferner die Kreislanfszeit ¢ 

Sekunden, der Leber 3,8 Sekunden; — venise Blutheschaffenheit verlingort 
Janfezeit. 


64. Die Bluthewegung in den Venen. 


Die Blutbewegung in den Venen ist im allgemeinen eine d 
leichmibige Strimung, sie erfiihrt aber infolge der besonderen Bi 
lichkeiten der Venen mannigfache Abweichungen. Folgende Momente | 
hierbei in Betracht: 

1, Die relative Schlaffheit, grofe Dehnbarkeit und leic 
sammendriickbarkeit sogar der dicksten Stimme; — 2. die vie 
und zugleich geriiumigen Anastomosen unter benachbarten Sttimmer 
in gleicher Gewebslage als auch von der Oberfliiche zur Tiefe hin. Hi 
ist es miglich, dab bei partialer Kompression des Venengebietes | 
noch zahlreiche, leicht dehnbare Wege zum Ausweichen findet, ) 
also einer wirklichen Stauung vorgebeugt wird; — 3. das Vorhat 
zablreicher Klappen, welche dem Blutstrome nur die centripetale T 
gestatten. Diese feblen in den kleinsten Venen, sie sind am zahlr 
in den mittelgrofen. Hydrostatisch sind die Klappen dadurch vo 
Bedeutung, dab sie lange Blutsiiulen (z. B. bei anfrechter Stellung 
Cruralyene) in Abschnitte zerlegen, so da® die ganze Siule nicht 
drostatischen Druck bis nach unten hin wirken lassen kann. 

Sowie ein Druck auf die Vene ausgetibt wird, schlieben 
winiichst unteren und 6ffnen sich die zuniichst oberen Klappen unc 
so dem Blute zum Herzen bin freie Bahn. Ein derartiger Druck w 
regelmisig auf dic Venen bei Contractionen der benachbarten M 
durch die Verdickung der Muskeln ausgetibt und so der B 
in den Venen beftrdert. Dab das Blut aus der geiiffneten Vene stir 
yorquillt, wenn die Muskeln bewegt werden, sieht man beim Ac 

Abweichonde Anschauungen fiber die Blutbewegung in den Venen und die | 
der Venenklappen siebo boi Ledderhose "4, 

Bei der Streckung und Au6enrollung des Oberschenkels e 
und kollabiert die Schenkelyene in der Fossa iliaca unter negativen 
druck, beim Beugen und Erheben fiillt sie sich strotzend unter ste 
Drucke. Durch diese pumpenartige Wirkung wird das Blut (mit E 
Klappen) aufwiirts geleitet. Etwas Abnliches findet beim Gehen statt( Bre 


65. Die Blutbewegung in den kleinsten GefiSen, 


Methode. Die Strombewegung des Blutes innerhalh der kloinston Gefitbe 
gfinstiggon Objokten direkt mikroskopisch beobachtet werden. (Malpighi boobacht 
(1661) den Kroislauf in don LungengefiSon des Frosches,) Als Objokte sint 
fir durchfallondes Licht: — der Schwanz von Froschlarven und jungen Fis 
Schwimmbant, die Zunge, das Mesentorium oder die Lungo cururisierter Frosch 





[6h] avaw tnd Geransehe in den GefiBen. 


weit in bad wvasendiFen Gowebe ‘orien ders (Fig. 60). Bs ist zweifelhaft, « 

die etwa vorhar interendothelialen Stomata hindus 

cder ob re einfach zwischen don inlothelion darch die Kittsubstam: hinduri 

($49. 1). — Hering ™ beobachtete, daS sogar unter normalen Verhdltnissen au 

Gefen, welche yon Lymphriumen umgeben sind, die Zellen in letetere eintrote 

das Cherwandern weifer, J& sogar einiger roter Hesiearperch ans den Kieinen 1 
in die LymphgofiBe fir einen normalen Vorgang. 


66. Tine und Geriiusche in den Gefiifen. 


1, Arterien, — In der Carotis (seltener in der Subclavia) hirt man bi 
aller Gesunden zwei dentliche Tone, welche nach Dauner und Hohendifferenz den by 
tinen entsprechen und dnrch Fortpflanzang dos Schalles vom Herzen entstehen: 
leitete Heratino*. Durch die bel der Systole des Herzens entstehende cela 
der GefaBwand kann abor anch in dem GefaS selbst ein Ton, 

Herston, entstehen. Mitunter ist our ae zweite Herzton allein vernehmbar, ¢ 
stehangsort der Carotis niiber gelogen ist. 


‘Obt man auf eine beschrinkte Stelle einer stirkeren Arterie, x. B, der A, crar: 
Druck ans, dor so in seiner Stirke bemessen goin muf, daB ‘nur noch eine d 
des Lumens fir den Darchlauf des Blates fibrig bleibt, so entstehen die sog. ! 
gerausche. Bs dringt dann durch die verengte Stelle mit groBer Schnelligkeit 
‘cin feiner Blutsteahl in dio hintor der Kompressionsstolle belegene weitere 
Seblagader, der als .PreGstrahi* die Fitssigkeitsteiichen in lebhafte Osxi 
und Wirbelbewegungen versetzt und hiordurch das Goriusch im der per 
woiteren Rohrenpartic orzougt. Analog vorhilt es sich an Knickungen, sc 
und Schlingelangen der Schlagadern. 


Kin Gerdnseh dieser Art ist auch das an der Subclavia bol Pulse mit 
bare ,Subclaviculargeriusch*, Es entsteht durch Verwachsungen der boic 
‘Matter an den Lungonspitzen (namentlich bei Longenkranken, Tuberkuldsen), w 
‘A. subelavia durch Zerrung und Knickung eine lokule Verengorung erfihrt, die 
an der Verkleinerung oder am Fehlen der Pulswelle in der Radialis (Pulsus 
mitunter nachweisen 1i8t. — In gleicher Weise entstohen Geriusche — n) 
A on einer Stelle eine pathologische Krweiterung (An 
bexitzt, in welche hinein der Blutstrom von dem normalen engen Rohre any si 
— b) wenn seitens eines Organes anf cine Schlagader ein Druck ausgelbt v 
@urch den stark vergriferten Uterus in der Schwangerschaft oder durch einen 
eraengten Tumor. 


Nicht genauer hinsichtlich der Art ihrer Entstehung bekannt sind das xier 
Gerinsch in den zahlreichen, stark gowondenen, orweiterton Arterienstiimmen des s¢ 
Uterus (.Uterin- oder Placentargeriinsch*), forner das viel weniger deutli 
beiden Arteriae umbilicales, .Nabelstranggerdnach*, das an den dinnwandig 
fest der Hiilfte der Siuglinge bhirbare .Gehirngordusch*, sowie das Gerius 
krankbaft vergroBerton Milz und das Schwirron in der Sehilddriise bei Morbus 


2. Venen. Das Nonnengerdusoh. — Oberhalh der Clavieula, in dem 
awisehon den Urspringen der beiden Kopfe des Sternocloidomastoidens, und xwa 
figstan rochts, vernimmt nian bei animischen und cblorutischaa, xuweilen aber at 
snodeo Menschen entweder cin kontinaierlicbes oder ein dor Diustole des He 
aich der Inspiration entprechendes rhythmisches Geriusch yon sausendem ode 
dow, selbst xischendem oder singondem Charakter, welcbes innerhalh des Bulbas dor 
laris communis entsteht und als Nonnengeriusch (Noone = Brummkreisel) bezel 
Die Uraucho des Nonnengorduschos liogt in dom wirbolnden Rinstrémen des 
dom rolativ engen Toile dor Vena jugularis communis in den darnnter liegenden, 
Bulbus derselbon. Hierdurch ist os vorstindlich, daf Druck hegiinstigend fiir da 
des Goriusches wirkt, obenso Soitenwondung des otwas erhobonen Kopfos. Aucl 
Schnelligkeit dos Blutatromes wird dio Intensitit des Geriusches gosteigert 
erklfirt o# sich, daf die Inspiration und die Diastole des Herzens (beides d 
Strom efurdernde Moments) das Nonnengeraiusch verstiirken. Dasselbe gilt von dev 
Wirkung der xufrechton Kirperhaltung, 











[e68) ar ~""uD des Blutes, Vergleichendes, 


4. Auch bei bet ‘Transfusion defibrinierten Blutes sind ¢ 
mistiinde beobachtet Worden: vielleicht infolge des in dem de, 
Blute enthaltenen Fi Prinfermentes, Nach Freund‘ ist jedoch 
Defibrinieren im Blute entstehende, Fieber erzeugende Substanz vo 
ferment yerschieden. Landois hat Tieren mit gutem Resultate BI 
fundiert, das nicht defibriniert, sondern durch Zusatz von Bluteg 
ungeripnbar gemacht worden war, 

Infolge der zahlreichen. Bedenken, die einer Transfusion ¥ 
entgegenstehen, hat man hiiufig mit gutem Erfolge statt dessen 1 
sionen einer isotonischen (0,9°/,) Kochsalzlisung (vgl. Bre 
a it. Diese kénnen an sich zwar keine belebende Wirkung 
sie kinnen aber doch auf rein mechanischem Wege die Kreislar 
nisse bessern, Nach einem gréferen Blutverluste vermag das | 
Rest des Blutes nicht mehr im Kérper umberzutreiben, weil das 
system zum Teil nicht geftllt ist; wird jetzt durch eine Kochsalztr 
die Menge der im Gefiiésystem vorhandenen Flissigkeit wieder 
vermehrt, dai cine Bluthewegung durch die Herztiitigkeit miglic 
reichen eventuell die noch vorhandenen roten Blutkérperchen aus. 
Leben zu unterhalten (Goltz'%, Kronecker u. Sander), In Fill 
gradigen Blutverlustes freilich, in denen die noch vorhandenen BI 
chen unzurecichend sind, kann nattirlich eine Kochsalz-Transfa 
Blut-Transfusion nicht ersetzen (Landois'®), 


68. Vergleichendes. 


Wirbeltiore, — Das Herz dor Fische (Fig.51, 1) sowie der kieme 
Larven der Amphibion ist ein einfaches, venises: os besteht aus Vork; 
Kamnier, Aus der Kammer flieSt das Blut au den Kiemen, von diesen artorinlisiey 
es sich 2ur Aorta, fliebt in alle Kérpertoile und kebrt endlich durch die Kirpy 
und Venen, die sich zu einem Venensinns vereinigen, wieder xam Vorhof uric 
Amphibien (Frosch, Il) haben zwei Vorkammern und cine Kammer. Ai 
entspringt nur ein Geffil, welehos die Arterixe pulmonales abgibt und als Aorte 
Korperorgane versorgt. Die Venen des groBen Kreislanfes vereinigen sich au oi 
sous, der in den rechten Vorhof fahrt, die Venen des kleinen Kreislaufes miin 
Haken Vorhof. Bei den Amphibien und teilweise bel den Fisehon (Ganoiden, Pl 
Dipnoern) entspringt die Aorta aus einem selbstiindig pulsierenden Horzabschnitt, « 
cordis oder Conns arteriosns, Bei den Reptilien (II und IV) sehreitet die 1 
Herzens in vine rechte und linke Halfte weiter fort, indem auch die Kamm 
Abdteilungen zerfillt, Die Scheidewand der Kammer bloibt aber bel den Schlangen, 
und Schildkriten darchbrochen; bel den Krokodilen ist sie vollatindig, doch bleib 
eine Kommunikation (Foramen Panixxie) zwischen linkem und rechtem Aortenboge 
— Alle Vigel und Saugor haben, wie dor Mensch, zwei getrennte Vorkat 
zwei getronnte Kammorn. — Das niodorste allor Wirbsitiere, Aniphioxus, 
dorsalen und ventralon GefiiBstamm, welche durch Zablreiche Querschlingen yorbu 
cinzclne Absehnitte dieses GoftBapparates pulkieren, cin eigontliches Herz fohlt. 

Wirbollose. — Bei den Tunicaten findet sich ein an der Ventralseite + 
gelogenes Horz, die BlutgefiBe fahren in Lackensysteme der Loiheswandun, 
Mollusken haben ein dorsal vom Darm gelegenes Herz, welches das von don 
organen Kommende arterielle Blut aufnimmt und in fberwiegend geschlossene 
nach den Organen lsitet. Blutlacunen sind in den Verlauf der Geflibe uber ar 
goachaltot, wo wie boi den Cephalopoden Arterien snd Venon durch Capillaren verb 
— Boi den Arthropoden bildet ein an der Dorsalsvite dos Darmes vorlaufend 
tiler Liingsschlauch, das sog. ,Rickengefib*, das Centralorgan der Circulatio: 
ist in mehrere Abschnitte (Kammern) geteilt, von denen joder durch eine rechte 
Querspalte (venise Ostien) das zum Herzen stromende Blut aufnimmt, durch ef 
Oifnung (Aorta) wird das Blut rhythmisch in die Zwisehenriiume der Korperorg 
stoBen. Geschlossine GefiBbabnen fehlen. — Die Warmer haben 2um ell ther 
eigones Gofidsystam, hei anderen ist ein solehes necanriay eae eee 


lly 
bei den Anneliden: ein dorsales und vente! pire nee | 











ay ~sserwn saat 


an 
legte. Gatenus (130-200 8 [ee yiteh Vivisektioen, Wo immor* — sagt 
tine Artorie verletae, 24,.°2) Blut hervortreten, Und wenn ich durch zw: 
ein Stick Arterie on be!" Seiten untorband, #0 habe ich gexeigt, da® das 
‘voll Blut war.* 

Man hielt aber auch jetzt noch an der alloinigen centrifugalen Blut 
fest; zwischen dem rechten und dem linken Herzen nahm man irrtimlich 
Offnungen fm Septum an. 

ape Serneto (spanischer Dominikaner-Zigling, theologischor Schriftstellt 
1553 in auf Calving Antricb als Ketzer verbrannt) zeigte zuerst, dab das 
Herzens ohne Offnungen sei; er suehte daher nach einer Kommunikat'on zw 
rechten und linken Herzen, und so gelang es seinen Forschungen (1546), di 
Kreislauf xu entdeckon; ,fit autem communicatio hace non per parietam cor 
( \}, ut vulgo ereditur, sed mngno artificio a cordis dextro ventriculo, lon 
mones ductu, ugitatur sanguis subtilis; a pulmonibus pracparatur, flavus efticitu 
arteriosa (Arteria pulmonalis) in arteriam venosam (Venice pulmonales) transfy 
Fast cin Vierteljabrhundert spiiter yerfolgte Cacsalpinus die Baln des gro 
Janfes (1569): bei ihm kommt znerst das Wort .Cireulatio vor. — Weiterh 
and hestiltigte auch Fabricius ab Aquapendente (Padua, 1574) ans der Stellung 

ner untersuehten Venenklappen [welche schon um die Mitte des 5. Jahrhune 
us, Bischof yon Syrien, ferner auch Jac, Sylvius, Vesatius (1543) 4 
1546) erwihnen] die centripetale Bluthewegung in den Venen (welche bit 
ies als centrifugal gegolten hatte; doch kannte schon Vesa! den contripe 
in den Hauptstiimmen). William Harvey, Schiiler des Fabricius (bis 1604), 
endlich (1616—1619), teils anf eigone Forsehungen sich stiitzend, tells die Eig 
feGhoren Forscher zusammenfassend, das Bild des Gesamtkreisiaufes, die 
slologisehe Errungenschaft (vervttentlieht 1628), von welcher eine neue Epoche 
logic anhebt, 

Nach Hippokrates ist das Herz tleischig und die Wurzel aller Gefide; b 
emselben die groBen, aus dem Herzen hervorgehenden GefiBe, die Klappen, 
fiden, die Herzohren, der Schlu8 der Semilunarklappen. Aristofeles benennt 
Aorta und die Hohlvenon, die Schule des Erasistratus dic Carotis, dieser d 
dic Funktion der vendsen Klappen. — Bei Cicero findet sich die Unterseheidur 
Arterion and Venen, Cefsws (5 n, Chr.) betont, daB die Venen, unterhalb einer Ke 
binde angeschlagen, bluten. Aretacus (50 n. Ohr.) weil, dal dus Arterienblut hell, 
biut dunkel ist, da das yendse Blut spiiter gerinnt, dal arterielle Blutungen we 
zu stillen sind als venise, — Phinius der Altere (+ 79 n. Chr.) sehreibt der 
die pulsierende Fontanelle au. Dax Vorhandensein wines Knochens im Septa 
Stuger (Bos, Cervus, Elephas) war Galen (130—200 n, Ohr.) bekannt, Nach 
tmutong kommunixioron endlich die Venen mit den Arterien durch feinste Rohren, 
dings orst de Marchetfis (1652) und Blancurd (1676) dureh Injektionen und Maly 
mikroskopische Beobachtungen der Kreislaufsbewegung beim Froseh (1661) a 
Cowper (1697) bei Warmblittern erhiirten konnten. Sfenson (geb. 1638) konstat 
die muskulise Natur des Herzens, was freilich schon yon der hippokratisehon | 
drinischen Schule ansgesprochen war. — Cole erwies die kontinuierliche Erwe 
Arteriengebietes gegen die Cupillaren hin (1681). — Joh, Alfons Borelli (1608. 
rechnete xuerst die Kraft des Herzens nach hydranlischen Gesetzon, — Craa 
besehrieb bereits systolische Contractionen an den Venae pulmonales, — Loewwerl 
die anastomotisebe Verkniipfung der Herzmuskelfasern untereinander. Chirac (1) 
band, allerdings resultatlos, beim Hunde cine Kranzarterie des Herzens, — Tj 
den roten Blutkirperchen entdeckte Menghiné (1746). — Aristoteles kennt bereits 
Wirkung des Kohlendanstes; Porcia wihlt dureh ihn freiwillig den Tod. — Der 
wurde schon bald nach dem trojanischen Kriege von griechisehen Arzten auaget 

Die ersten Andentungen ber den direkten Blutaustansch zwischen zwei 
‘yon Gefi® xn Gefi® leiten bis zur Zeit vor Cardanus (1056). Im Ansehinsse + 
deckang des Blutkroislanfes wnrde sodann in Kngland im Jahre 1638 yon Potter 
die Ansfihrbarkelt der Transfusion erwogen. Zahireiche Versuche wurden an 'T 
stellt; namentlich an verbluteten suchte man durch Cberleitung frischen Blutes 
wieder zu erwecken. Der Physiker Hoyle sowie der Anatom Lower waren bel | 
suchen besonders titig (1 Man verwendete toils dus Blut dersetben, 
anderon Art, Die erste Transfusion an einem Menschen wurde yon Jean Den 
1667 mittelst Lammblut ansgetiihrt. Saher a 

Die Alten (Israeliten, — Bmpedortes, Kritiag, Lucretia) vote 
den Site des lebenden Prinaps fir den SD und sogar die Seele selbst 


Aristotetes, Galen). 


















we daemonmeme 1g re Mee 


BA, 1904, 373. — 804. rope: S.A. 21, 1909, 405. — 88. Wolfens 
‘Arch. £ Kindorbeill- 58; 1910, — 89. Ribemont: Archives do tocalogie, 18 
QO. L. Seitz: *alioals Samat tia, V Vortriige N. P. Nr, 320, 1901, 488. —= 91. 4 
mann: Die Hamolynamik. Leipaig 1850, 177. — 92. ‘A. Fraenkel: AP. P. 40 
— 13. K. Brenner: In. Diss, Stuttgart 1912. — 94. I. Stiabel: P. 
05. F. Hofmeister: P. A. 44, 1889, 360. — 96. Fr. N. Schulz: P. A. 115, 19( 
97. I. Cohnatein uw, N. Zuntz: P. A. 34, 1884, 173. 42, 1888, 842. — 98. BWP 
20, 1906, 123. — 99. Worm-Maller: 1. B. 25, 1873, 573. ‘Transfusion ur 
Kristiania 187). — 100. E. Regéezy: ¥. A. 87, 1885, 73. — 101. Feder 
188s, 833. — 102. Grebner u. Griinboum: Wom. P. 1899, 2083. — 108. 
DAL. M. 74, 1902, 253. — 104, 0. Moritz: D. A. k. M. 77, 1903, 389, — 10 
teins Zk. M. 50, 1908, 824. — 106, Stursberg: DA. ke M. 90, 1907, 562, — 
wwe: Meditin. Jahrbiicher 1882, 200. — 108, Kornfeld: Wien, med, Blitte: 
Nr. 30, — 109, 0, Millers DN. ke M. 74, 1902, 316, — 110, Mee, Borns 8.4 
127, — 111, 0. Frank: ZB. 46, 1905, 441. — 112. G, Heinricins u. H. Krom 
44, 1888, 411. — 115. Traube; Gosammelte Beitr, 2, Pathol. u, Pate 1, 187 
11d, E, Hering: SW. A. 0, 2. Abt., 1869, 829. — 115. Fredericg> A.B. 8 
= 116. S Mayer: 3. W. A. 74, 8. Abt, 1876, 281. —— 117. F Mora 
2 L. B. 27, 1875, 149. — 119. WP. Lombard: C- 
157. A.J. P. 29, 1912, 335. — 120. Hc. Recklinghausen: A. P. P. 55, 190 
121. 4. Basler: P. A. 147, 1912, 393. — 122. ©. 8. Roy u. J. Graham Brown: 
188), B23. — 123. Hr. Recklinghausen: A. PP. 56, 1906, 468. — 124. 1 
e P. 10, 1912, 241. — 125. Burton-0 



























136. ean fassendo Darstellang: KR. Tigerst if 

127. A. Beutner: Tet, MeN. B. 2, 1852, 97. — 198. Ph, Knoll: 8. W. A. 97, Al 
207. — 129, Badowd: Arbeiten ans dem physiol, Luborat. d. Wiireburger Hoe 
1876, 237. — 190, Fr, Goltz a. J. Gaule; PA. 17, 1878, 100. — 131, 
BA. Starting: 3.0. P, 47, 1914, 286, — 132. 0. Funke u, J. Latechenberger 
AST7, 405. 17, 1878, 547, — 133. Quincke u. Pfeiffer: A. A. P. 1871, 90, — 
Bowditch w. G,M, Garland: J, 0, P. 2, 1879, 91, — 135. S.de Jager: P. A, 
426, 27, 1882, 152. 33, 1884, 17, 36, 1886, 309, 89, 1886, 171. — 136. A.) 
#, Miller: SitzBer. d. Gosellsch. x. Beférderung d. Naturw. 2. Marburg 1913, 
137. M, Cloetta: A. P,P. 63, 1910, 147. 66, 1911, 409. 70, 1912, 407. P. A, 
B39. — 138. Th. Openchoweski: P. A. 27, 1882, 233. 7. 
139, Lichth 
A in 1876, 













ry : Diss, Halle 1846, 
Boinikoe: ALP. 1886, 1. Ki. Harthle: B.A. 9%, 1908, igs” 
seheinangen und Goxotze der Stromgeschwindigkeiten des Blutos, Frankfurt 
144. Chaurean, Bertotus a, Laroyonne: Journ. dela physiol. 8, 1860, 695. 
Recherches sur la vitesse fue cours du sang dans Jes arthres du cheval an moyen 
i: P.A. 37, 1885, 382. 0. F 
Laborat. d. Zirieher or 
254. Stud 
: ZB. 50, 




















a, 
1869, ot. "W.V.N. F. 20, 1886, 
fehre. Freiburg 1802. Z. ¢ Pu. T. 
— 150. EB. Hering: Zeitschr. t. Physiologic. Ss 1820, RD. 
2. — 151. L. Hermann: P. A. 38, 1884, 169. — 152. ©. Keri 
Festschrift £ Ludwig. 1887, 101. — 143. @..N. sf 
— 154. G, Ledderhose: Dm. W. 1904, 1563. Mitteil. ons d. Grenzgebieten d. Mediz, 
15, 1905, 355, — 155. WY. Browne: L. B. 22, 1870, 261. Beitriige x Anatomie 
1. Ludwig. 1, 1875, 1. — 156. A. Schklareesky: P. A. 1, 1868, 
— 157, J. Cohnheim: V. A, 40, 1.41, 1867, 220. — 168. B. Hering: 8. W. A. 
1867, 691. — 159. 1, Landoie: Die Transfusion des Blutes, Leipaig 1875. Deutac 
f. Chirurgie 9, 1878, 457. M. m. W. ). Kulenburgs Real-Eneyelopid 
i Panume V. 27, 1863, 



















%. kM. 48, 1908, janet 165. iy 
tel, Sender: Bok. W. 1879, 767. D. m. W. 1884, 507. 





Uygyois- HOS OMARG: PhrslOle gig, Want 





vere pin cer LReM,— 


Die Grobe der aa, ist verschiedon, im Mittel wtwa 
dor Alvi Millionen: 


der Lungen — gebiiren 2wei vain Systi 
system de ee Tolmonalgefie: (kleiner Kreislauf). Die Verzweigungen 
denen der Luftkanile, welchan sie unmittelbar mae Die Lan} 
men gleichfalls die Luftkanale begleitend, sind zusammen enger als 
is. roerny (Wasserabgabe in den Lungen). 


Pig 62. 








Vilelionsnsicht mehreror Lungeosiveoten  d Alveole wit den Binteapiiinren (e), + 
ren, die Alveols abgrouzonden GefkBen (gy). — H Das Rpithel einer Aly 
aloes Pistisheo, 9 erase, verschmsiaene, heralees Platten, — © Fite 
pillaren, — D Alvgote, deren ain) 
# Alveols, deren Bogrenzung alle 
elastischor Fasorn (//) daryostallt int. 







B, Das System der Bronchialgefabe (grofer Kreislanf) - 
niihrongematorial fiir das Atmungsorgan. Zwisehen den Versweigung 
bronchiales und pulmonalis bestehen vielfache Anastomosen (Zucke 
den Cypillaren hervortretonden Gefibe gehen tells in die Anfinge der 
Gber (aus diesam Grunde haben alle erhoblichen Stauungen im kleine 
Stanungen in dem Blutlanfe dor Bronchialschleimhaut, verbunden mit 1 

zur Folge) — toils bilden sie besondere Venonbaknan, die als Venae |) 
intron Mediastinalranm in die Stimme der Vv. azygos, intercostales 


Giiad intessBlllbs ‘Oswebs: der Langen at) voel siacm| Notaweck 4 
; um die gréGoron Bronchien, die Lungeniipehen und die G 
sich ein grobores, unrogelmiliges Lymphgefibnets (Mitler*). Das Sa 


wey “<enmsiuy Wer ssuMUNweRUMET. 


| 


 wiachen Langen0Perfliche und Brustranminnenfiiche (Pneum 
We betreffende LYMSC ist hierdurch fir die Atnun, keit It 
oppelseitiger Pne™Mothorax zieht demnach den Tod nach sich. 


An menschliche? Leichnamen kann man die Grofe des elastischen Zuge: 
in der Weise mossen, da man durch vinen Intereostalranm ein Manometer bis in 
raum einfigt, — oder indem man das Manometer in die durchschnittene Luftril 
und nun Se Lsconeed Pneumothorax macht, Nach Jeteterem Verfahren fund 
het Exepirationsstellung 6 mm, bei Inspirationsstellung bis 30mm Hy, — A 
fand Aro#™ bel rubiger Inspiration 4,64, bel rubiger Exspiration 3,02 vem Hy 


Werden mit der inspiratorischen Erweiterung des Brustk: 
gleich auch die Lungen ausgedehnt, so wiirde — falls flr diese 
niichst die Glottis geschlossen wire — eine Verdiinnong 
innerhalb der Lungen stattfinden, da sich ja das Volumen diese: 
ein gréBeres ausdehnen milite. Wiirde nun plétzlich die Glottis 
so wiirde die atmosphiirische Luft so lange in die Lungen ei 
bis die Lungenluft gleiche Dichtigkeit mit der Atmosphiire erlangt 
Umgekehrt: werden mit dem Brustkorbe bei der Exspiration 
Lungen verkleinert. so wiirde — falls wir uns zuntichst ebenso dii 
ritze geschlossen denken — die Lungenluft verdichtet, d.} 
Kleineres Volumen zusammengepreft, Wtirde nun plitzlich die € 
éffhet, so wiirde soviel Luft aus den Lungen entweichen, bis i 
anfen gleicher Drack herrsehte, Da beim gewohnlichen Atmen d 
ritze offen steht, so wird der Ausgleich des verminderten oder vi 
Luftdrnekes in der Lunge bei der In- und Exspiration allmihlich 
Aber auch so noch herrscht wihrend der ruhigen Einatmung ein 
negativer, bei der Ausatmung ein geringer positiver Druck in der Ly 


Sotet man hei Tioren ein Manometor mit einer seitlichen Trachealélfnu 
bindung, wahrend die Atmang ungehindert bleibt, so zeigt sich bel jeder Bins 
negative, bei jeder Ansutiang eine positive Drackschwankang. Fir den M 
Ponders” don Versuch in der Weise modifiziert, dab er bel geschlossenen 
U-+firmige Manometerrohr mit ¢inom Nusenloch verband bei Oltenbalten dos + 
nan ruhig in- und exspirierto. Er fond, da bei joder ruhigon Inspirati 
einen negativen Druck yon 1mm anzeigte, bei jeder Exspiration einen 
von 2—3 mm. Aron * beobachtete bei Operiarten mit Trachealfistel bei der Lusy 
bis —6,6 mm Hg, bei der Exspiration + 0,7 bis + 6,3 mm Hg; (beim Sprox 
die entsprechenden Schwankungen —ti und +7, beim Husten — 6 und + 46,1) 
Maund- and die eine Nasendinang geschlossen sind, so da das in der anderen S 
befindliche Manometer allein mit dem Respirationskanale kommuniziert, und no 
enorgisch in- und exspiriort wird, so botriigt der griBte Inspirationsdrack —57 m 
der stiirkste Exspirationsdeuck +- 87 (82—100) mm (Donders**), 

Trotz des hiheren Exspirationsdrackes darf nicht geschlossen werden, d 
atmungsmuskeln kriftiger wirken als die Kinatmungsmaskeln, denn ex mal b 
wtmung eine Reihe von Widerstiinden tberwanden werden, so dad nach Cberwilti 
nur noch cin geringer Kraftaufwand fiir die Aspiration des Hg Gbrig bleibt, D 
stinde sind: — 1. Der elustischa Zug der Lungen; —- 2. Das Emporheben de 
des Thorax; — 3. die clustische Torsion der Rippenknorpel — und 4. das N! 
iler Raucheingeweide und die elastische Dehnung der Banchwandungen. Alle d 
stinde wirken bei der Ausatmang unterstiitzend fir die Exspirationsmaskeln, M 
hieranf kann es keinem Zweifel nnterliegen, daB die gesumte Kraft aller 
griBer ist als dio aller Exspiratoren (vgl. Stigler"). 

Der im Abdomen herrschende sogenannte -Abdominaldrock* wird nati 
den Atmungsvorgang becintlubt; doch gehen die Angaben dariber, in welche! 
sich bei don einzelnen Phasen dor Atmung andert, noch sehr auseinander. Nach 
ist das Verhalton des Abdominaldrackes davon abhiingig, ob die Tatigkeit des 
oder die der Bauchmuskulatur bei der Atmung iiberwiegt, 

Wird bei forcierter Einatmung die Luft in der Laftrvhre verdinnt, so ¥4 
verkiirzt sich dio ‘Trachea nobst den Bronchi; umgokehrt ist das Verhnlten | 
‘spiration (Nicaive , vgl. Kahn *). 

















Say veeeee Rapazitiit, Zahl der Atematige. 


5. Vitale Kapazitat — wird dasjenige Luftvolumen genannt 
von der hichsten 8pirations- bis zur tiefsten Exspirationsstellung 
Langen entweicht. ES betriigt im Mitel 3200 bis 3800 cm. 

Aus vorstehendem folgt, daS nach einer rabigen Einatmung ¢ 
Lungen etwa 3000—3900 em? Luft enthalten (1+2+3), nach eine 
Ausatmung (142) jedoch 2500—3400 em*. Hierans sowie aus 3. 
vor, dai mit einem gewthnlichen Atemzuge ungefiihr nur '/,- 
Lungenlutt geweehselt wird. 


Macht man withrend einer Reiho ruhiger Atomatige eine einmalige H-Insp 
matersucht, wie lange noch bei weiteren rubigen Atomzigen das H in dor Aus 
funden wird, so findet man gleichfalls, 
7 Vorlauf von G—10 Atomziigen die Lunge: 

ernouert (also H-frei) ist. 

Die Luft in dem Banme von der N 
bis xn den Bronchiolen nimmt am cige 
mungsvorgange, det Sauerstoffanfnahme ¢ 
silureabgabe nicht teil, 
der Alveolen abspiclen; 
licher Luftranm* bezeichnet. Nach J 
triigt er etwa 140 cm’, 

Die Bestimmung der ¥italen Kay 
geachioht mittolst des Spirometers von 
(Fig. 53). Durch eine mit einem Mundatich 
waite Rohre blist man (bei gesehlossenor N 
spirationsinft in eino ber Wasser anfgehit 
Gewichte im Gleichgewicht gebalteno), 
Gasometerglocke. Nuch vollendeter Ex 
wird die Rohre geschlossen und das Volun 
goatmoten Luft an der Glocke abgelesen. 
Fobler zu vermeiden, ist es notwendig, 
des Spirometers auf Korpertemperaty 
men (1. Hocaslin®™, Gebhardt™), — 
man zur Bestimmung auch eine Gasoh 

Yon Einflilssen auf die vitale 
sind bekannt: 

1. Dio Kérperlainge — (Hutch 

ararerensew pircendter. vitale Kapagitit steigt mit xunehmendor 
2. Das Rumpfyolumon — (C.H 
betriigt im Durchschnitt das Siehonfache der vitalen Kapazitit. 

8. Dus Kirporgewicht. — Eine Uberschreitung dex Korpergewichtes | 
nermalen Mittels hat anfiinglich fir jedes xunehmende Kilo cine Verminderang 
Koapazitiit um 87 em® zur Folge. 

4. Dos Alter. — Das 
vou hier anfwirts bis xm 
abanzichen. 

4. Das Gesehlocht — Arnold®’ fand im Mittol bei Minnern 3660, | 
2350 em. Ist bei biden Geschlechtern die K6rperliingo und der Brustumfang gle 
verhilt sich im Mittel die vitale Kapaxitit der Miuner zu derjenigen der Weiber 























. Lebensjuhr zeigt dat Maximam der vitalen 
br und abwirts bis zom 1. Jahr ist pro an 








74. Zahl der Atemziige. GréBe der Lungenventilat 


Die Zahl der Atemaztige schwankt bei Erwachsenen 
12—16—24 in einer Minute (4 Pulse kommen dabei im Mittel 
Atemzug). Dabei machen sich mannigfache Einfltisse geltend. 


1. Die Kirperhaltang. — Guy xihlte beim Erwachsenen im Lieg 
Sitzen 19, im Stehon 23 Atemztige in einer Minnte. 


2. Das Alter und Geschlecht. — Nach Chai 
liché Atmungsfrequens bei Kindern im Alter bis xu ei 






wird die maximale d 
Jahr beobachtet, dir 


{Srey penne “oMAERUNE Del Oar LxEpiration, Vas Waphragmas 


B. Exspiration. 
I, Bei ruhiger Atmung 
Dewirkt die Verkleinérang des Thoraxraumes lediglich die Seh) 
Brustkorbes, sowie die Elastizitit der Lungen, der Rippenkn 
der Bauehmaskeln. 
IL. Bei angestrengter Atmung wirken: 

1, Mm. intercostales interni (soweit sie zwischen den Rippen] 
liegen) und Mm. infracostales (Nn. intercostales). 

2. Die Banehmuskeln (Nn. abdominis interni sive anteriore: 
intereostalibus VIIL.—XII.). 

3, M, triangularis sterni (Nn. intercostales). 

4, M. serratus posterior inferior (Rami exteriores nervorum de 

6. M. quadratus lumbornm (Rami museulares e plexu lumb 


77. Wirkung der einzelnen Atmungsmuskeln. 


A. Inspiration. — 1. Das Diaphragma — stellt eine gegen den 
gewolbte Doppelkuppel dar, in deren griBerer, rechtsseitiger Konkayitit dir 
deren kleinerer, linksseitiger Milz und Magen liggen, In der Rube werden diese 
durch die Elastizitit der Bauchdecken wnd den intraabdominalen Druck #0 gegen 
Fliche des Zwerchfolls angedriickt, daB dieses sich in dio Thoraxhéhle hinoinw 
der elastische Zug der Langen beitrligt. Der Mittelteil des Zwerchfells (Centram 
ist oben groftenteils mit dem Horzbeutel verwachsen. Diese Stelle, auf welche 
rabt and die yon der unteren Hohlvene (Foramen quadrilateram) durchbohrt wii 

ruhenden Znst: 


Pig. 50. mehr gegen ¢ 
raum herab 1 


Zwerchfellabgt 
lich als die ti 
des Mittelteiles 
non (Fig, 56). 

Bei ¢ 
traction 
beide 1 
des Zwe 
abgeflach 
der Brustra 
ee hin; 

jerbei gel 
siichlich di 
len muskuli) 
Prootalschnitt durch den ‘Thorax an der Spitee dor 12. Lippe (rz. ¢) US dem g 
Jedersoits xur Demonstration der Gestalt dor Zwercbioll in der Bexpira- Zustande 
slow (4e-e) und in der Inspiration (%i- — Te Te rox we im Ex 
spirationsstadivin, (4 in der Inspieation, — CY Cantrom tendineom. Die mehr eben 
Preite svigen dle foxpiratoriseh erfolgends Richtuog der MewoxunR 8% Wohej gig 

gleich yon d 

wand, der sie in der Exspiration unmittelbar anliegen, abhet 
Mitte des Centrum tendineum, wo das Herz ruht, nimmt bei ral 
mung an der Bewegung keinen erheblichen Anteil, bei tiefster In 
senkt jedoch auch sie sich nachweislich. 

Boi horizontalor Lage und guter Belonchtung kann man, namentlich be 
oft die Bowegung des Zwerchfulls direkt sehen in Form einer wellenfirmigen 
wolche im (}. Intercostalraum beginnt und je nach der Tiefe der Inspiration | 
eostalriume abwirts dareblinft (Létten"), 
took jg 2M Zwerebfell kann anBer der Enwelteene jusdehnen: indo os niknlic 
ang gj, nteren Teile in transvorsaler Rich cece seittich ausenwsichen und 

Bingeweide des Abdomens Artickt, suche” 














von oben nach unten den T 





1ST = Seg pet der ane nt maRpIniuOR 

Pig. 57, 1 (linke Serer Figur) zeigt, dai hel Hebuag dor Sthbe sich die 1 

et fy ing der Intercostales oxterni), —- /m sich jedoch ver 

a ie. — Fig. If zeigt, daf die durch gh angedontet: 

eh '® ezeiehnoten Intereostales externl sich bei Hebunz der 

verkirzen. Bei Hetung def Rippon wiirde niimlich die Lage dieser Muskelzize di 
karzer gewordenen Diagonilen der panktierten Rhomben gegeben sein, 

Der Streit iber die Wirkang der Entercostalmuskeln ist uralt: — ¢ 
130—200 n. Chr.) hielt die Extent far Inspiratoren, die Interni fiir Exxpirato 

7 (1727) schloB sich (nach Willie’ Vorgango) dieser Ansicht an, er bex 
aueh noch die Intereartilaginel als Inspiratoren, — 4. ¢. Haller (Hamberyers entael 
Gegner) hetrachtate Interni und Externi belde fir Inspiratoren; — Vesaline (1540) 

fir iratoren an, 

Nach Landois ist es eine wiehtige Aufrabe der Externi und Intercartilagh 
Inspiratoriseben Dehaung der Intercostalrinme und dem gleichzeitig verstirkten ela 
Zuge dor Langan entgegen 2u wirken, Aufgabe der Interni, bel starker Exspirations! 
(x. B. Huston) der exspiratorischen Dehnnng Widerstand zu leisten, Ohne Muskelgegen’ 
wiirde auf die Daner der ununterbrochene Zug und Druck die Intercostalsnbstam 

Bei ruhiger Atmung sind die Mm. intercostales externi ui 
{ntereartilaginei allein als Rippenheber titig. 

Die Mm, lovatores costarum longi et breves, die wohl auch als Ripp 

werden, kinnen als solche fberhaupt nicht in Betracht kommen: 
hioter dor Drehnngsachse der Rippen angreifen, kiinnten sie nur dazu dienen, die 
ma senken, Da sie jedoch ganz dicht an der Drehungsachso angrelfen, konnten sie 
diesem Sinne nur eine sehr geringfigige Wirkung austiben. 

Bei angestrengter Atmung kommen als Rippenheber die Sc 
und der Serratus posterior superior hinzn, Der Serratus ani 
magnus, Pectoralis major und minor vermégen zur Hebung der J 
nur dann mitzuwirken, wenn die Sehultern unnachgiebig gehalten w 
teils durch festes Aufstiitzen der Arme, teils durch die Mm. rhomb 
wie an Atemnot Leidende es instinktmibig ausfihren. 


3. Auf Brustbein, Schliisselbein und Wirbelsdule wirkende Mu: 
— Bei fixiertem Kopfe (durch die Nackenmuskeln) kann der Sternoe] 
mastoideus durch Emporaiechen des Manubrium sterni und der Extn 
sternalis der Clavieula den Brustkorb wirksam nach oben hin dure 

wheben erweitern, die Scaleni somit untersttitzend, — In abnticher ' 
jedoch weniger erfolgreich, kann die Clavicularinsertion des Trap 
titig sein. — Eine Streckung der Brustwirbelsiiule mob-ein 
hebung der oberen Rippen und Erweiterung der Intercostalriiume zur 
haben. — Der Trapezius, die Rhomboidei, der Levator sca 
kénnen schlieBlich dadurch untersttitzend wirken, dab sie den Bra 
yom Drucke der oberen Extremitiit entlasten, 

4, Bei angestrengter Atmung wird mit jeder Inspiration ein Se 
des Kehlkopfes und Erweiterung der Stimmritze beobachte 
gleich wird der Gaumen stark emporgehoben, um dem dureh den 
eintretenden Luftstrome einen miglichst freien Weg zu bereiten. 

5. Im Gesichte priigt sich die forcierte Atmung zuerst durch 
ratorische Erweiterung der Nasenlicher aus (Pferd, Kaninchen). Bei hé 
Atemnot wird die Mundhéhle unter Senkung des Kiefers bei jeder 
ration erweitert (,Luftschnappen*). 


B. Exspiration. — Die ruhige Ansatmung verliiuft ohne Muskelwit 
auniiehst lediglich bedingt durch die Sehwere des Brustkorbes, w 
ans seiner erhobenen Stellung in die tiefere Exspirationslage zuriicl 

n wirkt die Elastizitit verschiedener Teile unterstiitzend mit. I 
Erhebung der Rippenknorpel, welche mit einer leichten Drehung 





3 
i 


ome Ger DUMgON= UU RErEErENECN 


7 
a 
; 
Bes 


dor AsMMinie big sum oboren Rande der 7. Ripe; links 
Tae 468 Nerzeng), dio untere Lungengremo orn Ble 
Linie @ fb die antere Grenze der ruhenden Lungen a 
Lnngen bis UF 10, Rippo, Warend einer milickst Mefen F 
Shere Rippe abwirts bis zur 7. nieder, 
wobel sich das Zworehfell von der ‘Thoraxwand abhebt. Bei a; 
aD regi enaspr re ee anc et a A 
sinken, (In Pig. 68 zeigt ma die Gronze des rechten Langenrandes bei 


Besondere jae gina die Lago des linken Langenrandes xum 
30 ist die fast dreieckige Stolle von der Mitte des Ansatzes der 4. Riy 
links vom Sternum sichtbar, an welcher das Herz bel ruhendem Thorax 
Pig. bt 
leerer 


HI 
i 





i 
i 





HH 
252 
ite 


direkt anliegt. In diesem Bereiche, welchom das Dreieck ¢ ¢’t* in 
zeigt die Perkussion die .Horzleere*, d.h. hier herrseht vollig 


Pig. 88, 





‘Topographic der Lungen- und Herzgronen bei der In- und Exspiration ouch ¢ D 


(,Schenkel-*)Seball. Im Bereiche dos groften Dreleckes dd’ d“, innerhalb 

relatiy diinno Lungenmassen das Hore von der Brustwand trennen (vel. Fig. 30) 

Porkussion .godimpfter* Schall zn hiren, Erst nach anfen davon ist ȴ 

*, Bei tieforer Inspiration schiobt sich nan der innere Rand der 1: 

Aber das Hors bis zur Insertion des Mediastinums (ygl. Pig. 30), wodurch ¢ 

bis anf das kleine Dreieck ¢ i i eingeengt wird. Umgekehrt weicht bei stirksten 
der Langenrand so woit zurlick, dafl die Horalocre den Raum f ¢ e umfabt. 


79. Pathologische Abweichungen 
yon den normalen Schallverhiltnissen am Brastkor| 


Andeutungen Gber die Perkussion (auch des Unterlelbes) Jassen 
Avetaewe (81 n. Chr.) auricktihron, Der eigentliche Erfinder ist jedoch A 
(£1809), desson grundlegende Arbeit (1761) namentlich von Piorry und Skod 
wurde; letsterer schaf dio physikalische Theorie dor Porkussion (1839). 

Im Berelche dor Lungen wird der sonst voll — oder lant — erkli 
knssionsschall gediimpft, wonn entweder die Lungen in geringerer oder gr 





ewes spent axa aggaguctmeonatee 


si. Pathologische Atmungsgeriusche. 


Dio Kenntuis det Stkkussions-, der Reibo- und mancher katarrhalischon ¢ 
reieht bis Hippokrates (460—377 y. Chr.). Die eigentiiche Erfindung dor phy 
begriimdeten Anskultation Tibrt yon Laénnee her (1816), ihre klassische Durchbil 
Skoda (1839). 

1. Das sbronchiale* Atmen — entsteht im ganzen Bereich der Lung 
wenn entweder die Luftblischen Luftleer geworden sind (durch ErguB), oder > 
‘Langen von aufen komprimiert werden. In beiden Fallen leitet die verdichtete 
snbstanz das bronchiale Atmen bis xar Thoraxwand hin. Auch innerhalb patho 
groBerer Hohlriume der Lungen, die mit einem gréBeren Bronchus kommunizie 
es vertiommen, fills diese hinteichend nahe der Thoraxwand liegen und ihre W 
ziemliche Resistenz haben, Hier kann e# entweder (bei mangelnder Lufthewegun 
Kaverne) lediglich ans der Trachea bin fortgeleitet sein, oder bei ausgiebigem Lu 
Kann (wie an der Stimmritze) am elnmindenden Bronchus ein Stenosengeriiuseh ¢ 
swelehes durch Resonanz in der Kaverne ,amphoriseh* wird. 

2, Das wamphorische* Atmungsgerdusch, dbnlich demjenigen, wel 
‘ateht, wenn eine Flasche angeblasen wird, —— wird beobachtet entweder, wenn in ¢ 
vine mindestens fanstgroBe Hohle sich findet, welche beim Laftwechsel a 
wird; — oder wenn neben einer teilweise noch Infthaltigen und ausdehnangsfihig 
sich Luft im Pleuraraum befindet (Resonanz). 

8. Findet die Luft anf ihrem Wege Widerstinde in den Lungen, so k 
verschicdene Atmungageriiusche erzeugen. — 4) Mitunter werden die Lungenbliisel 
in cinem Znge, sondern absatzweise mit Luft gefillt, wenn (namentlich in der 
teilweise Schwellung der Wiinde der Luftkaniilchen den stetigen Luftwechsel erachy 
ssuccadierto™ Atmungsgeriusch ist die Folge davon. — b) Ist ein zn einen 
gischen Hohlraum der Lunge fahrender Bronchus derart verengt, da die Luft in ¢ 
voribergchend Widerstinde erfihrt, so pilegt der orste Teil der Inspiration schar 
torisch G-artig zu lanten, geht dann aber fir die Daner der letaten */, der Inspi 
tin bronchiales oder amphorisches Geriinsch fiber: ,metamorphosierendes* G¢ 
—e) Wenn in griBeren Luftkanilen die Luft in dem Schleime Blasenspringen 
fo entstehon ,Rasselgeriusche*, In den kleinen Luftriiumen entstehen sie, 
Wandungen dergolhen bei der Inspiration sich entweder von vorhandenem flissig 
abheben, oder wenn sie aufeinander liegend sich plotzlich yon einander trennen, M 
acheidet fenchte (in wisserigem Inhalt) oder trockene (in zihklebrigom In 
stohende) Rasselgeriusehe, ferner inspiratoriache oder exapiratorische, ode 
nuierliche, — sodann groBblasiges, kleinblusigos, ungleichblasiges 
das sehr hohe Knisterrasseln, endlich das in groBen Hoblen durch Resonunz 
metallisoh klingende Rasseln. — d) Wenn die Schleimhaut der Bronchien 
achwellt oder mit Schleim so belegt ist, da® die Loft sich hindurchewingen mu, » 
in den grofon Luftkaniilen cin tief snmmendes Schnurren (Rhonchi sonori), in de 
ein bell pfeifendes Geriusch (Rhonchi sibilantes). Bei ansgedebnten Bronchial 
fihit man nicht selten die Brustwand durch die Rasselgeriusche erzittern (Bri 
fremitus*). 

4. Befindet sich in dor Plenrahdble bei xusammengesunkener Lange Laft anc 
keit, so hirt man bei Erschiitterang des Thorax ein Gerinseh, wie wenn Wasser 
in einer goriumigen Flasche geschattelt wird (das Sukkussionsgerauach de 
krates), Selten vernimmt man iihniiches (huher kiingend) in fanstgrofen Lungen! 

5. Wenn die ancinandor liegenden Blatter der Plouron durch entstindliche 
rauh geworden sind, 80 verarsachen sie, indem sie bel den Atembewegungen «i 
cinander verschicben, cin Reibephinomen, das toils gefahit (of von dem F 
selbst), trils gehirt wird. — Reibegeriusche kommen auch bei der Herzbewegnng 
den beiden Blittern des erkrankten, rauhen Perikardiums vor (§ 48, S. 122). 

G. Beim lanten Sprechen oder Singen wird die Wand des Brostkorbes mite) 
(.Pectoralfremitus"), weil die Schwingungen der Stimmbiinder sich durch 1 
Bronchinlveraweigung fortptlanzen. Die Erschiitterung ist natiirlich im Rereiche 
rohre und der grofen Luftkaniile am stirksten. Das anfgelegte Ohr vernimmt 
Stimme nur ein unverstiindliches Summen. Befinden sich grofe Ergiiase oder Luft i 
faame oder verstopfen reichliche Schleimmassen die Bronchien, so wird der Pectors 
geschwacht oder aufehoben. Dagegen haben alle Momente, welche bronchiale 
‘Yerursachen, eine Verstirkung des Peetoralfremitus zur Folge. Lanter wird er 

Stellen gehort, wo anch unter normalen Verhiltnissen bronchiales Atmen 
anfgelagte Ohr hort in diesen Fillen eine varstirkte Schalleitung bis aur B 
-Bronchophonie*. 


Rosomann, Physiologie. 14. Aufl. } 








[s84) Methoden “~" “"CerSuchong des reapiratorischen Gaswochsels, 


5, Schnarchen? — ntsteht beim Atmen durch die gosffnete Mundhahle, i 
In- und Exspirationsstro™ das schist Siececkbeaniterd in aa 


seblotternde Bewegungen Versetzt, Moist im Schlafo unwillktrlich; anch willktrlic! 


6. Gurgeln: — besteht in dem goriinschyollen, langsamen Hindurehtreten! 
Exspirationsinft in Blasenform durch eine bei riickwirts jeneigtem Kopf in 
zwischen Zange und weichom Gaumen gehaltene Fitixsigkeitamasse, WillkGrlich, 


7. Weinen: — Darch Gemitsbewegnngen hervorgerafene, kurze, tiefe In- 
ygetogene Exspirotionen bei verengter Glottis, erschlaiten Gesichts- und Kiefermus) 
enter der M. xygomaticns minor titig), anter Triinensekretion, oft mit klagenden, wnart 
Lantinlerungen verbunden. Bei intensivem, Linguram Weinen entsteben stoBwelse ) 
Heh erfolgende unwillkiirliche Zwerchfelleontractionen, welebe durch yrentilartige 
einandersehlagen der Stimmbinder das als — Schlachzen bekannte Inspiration 
erzeugen. Nar unwillktirlich. Das so hdefige Schtachzen in der Agone ist nach 
dareh cine Reizong der beim Absterben hochgradig erregbaren Nn. phrenici ¢ 
Aektrischen Vorgiinge bei der Contraction des Horzens 20 erkliren, — Seufzen 
gedehnte Atembewogung mit moist klagendem Lante, oft nnwillkirlich durch sch 
Affekte erregt. 


8 Lachen: — Kurze, schnell erfolgende Exspirationsstoe dureh die meixt 
‘Tinen gespannten, bald genaherten, bald von einander entfernten Stimmbiénder 
unter charakteristischen, unartiknlierten Lanten im Kehlkopfo mit Eraittern des 
Ganmons, Mund moist offen, dag Antlite durch Wirkung des M. zygomaticus ma} 
des M. risoring) mit charaktoristischem Zoge. Meist anwillkfirsich darch Vorstellan 
sehwache sensible Reize (Kitzeln) erregt und durch den Willen (dareh forciert 
sehinf und Atemanhalten), ferner anch darch schmerzhafte Reizung sonsibler Nerve 
anf Zange oder Lippen), jedoch nur bis 2a einem gewissen Grade (,Augpl 
unterdrtickbar. 


9. Gihnen: — Langgezogenes, tiefes, unter sukzessiver Aufbietang gable 
spiratoren erfolgendes Kinatinen bei weit gedffnetem Munde sowle offonem Gaume 
Gilottis; Exspiration kiirzer, beide oft mit langgezogener, gedebnter, charakteristisc 
Sinferang, auch unter allgemeinam Strecken und Reckon. Meistens unwillkirlich, err 
Schiiifrigkeit oder Langeweile, doch auch willkiirlich nachxuahmen. 


84. Chemie der Atmung. Methoden der Untersuchung 
respiratorischen Gasweehsels.* 


Die Untersuchung dos respiratorischon Gaswochsols orfolgt in_verschiodener 
nachdem man das Verbalton des Gaswechsels wilhrend eines bingeren Zeitraumes (2: 
und mehr) oder wihrend kirzorer Zoit (15 Minuten bis 1 Stunde) feststellen 
arsteren Fulle muf natirlich die Versnchsperson oder das Versnchstior sich ix 
geschlossenon Raume befinden (Rospirationsapparat); die durch die 

Veriindorangen in der Znsammensetzung der Luft dieses Raumes werd: 
sucht Hierbei wird aufler der Langonatmung auch die Perspiration durch die and 
fostgestellt. Soll dagegon die Untersuchung dos Gaswochsols anf kiirzero Zelt b 
werden, so gonligt os, die Versuchsperson oder das Veranchstier darch ein Mu 
atmen xn lusson; durch gecigneto Ventilo wird dafiir gesorgt, dal die Finatme 
Ausatmungsluft durch zwei gotrennte Rohrisitungen atreieht und so untersncht wen 


I. Untersuchung des respiratorischen Gaswechsels in lé 
Zeitriumen. — Die Respirationsapparate. — 1) Reynault v. Reisets® 
(Pig. 59) besteht aus einer Glocke (R), in welcher sich das Versuebstier (Hound) 
(Um dicselbe herum ist die Zylinderhille (yg) gesetet, die eventnell xu ecalorim 
Versuchen beniitat werden kann, wozu bei f cin Thermometer angebracht ist.) In 4 
(RD (Mhrt zundchst das Rohr ¢, wolches die (in Pig. 59, O) gemessenen Mengen ¥ 
‘stoff (welcher in Fig. 59 CO, die noch etwa beigemischte Kollensiure an Kalilauge 
soll) zulcitet. Dax MaBgefid fir den Sauerstoff (0) wird durch eine Chlorealciumlé 
der mit grofen Flaschon versehenen Chlorealciumwanne (CaCl,) nach A hin enth 
FB ans fohren die Rohren d und e, durch Kautschukrohren mit den kommunizierer 
dlaschen (KOH, koh) verbunden, welche durch einen Wagebatken (1) abwechseln 
und gehoben werden. Hierdurch aspirieren sie abweehselnd die Taft aus F and 


>; a lie Gewiehten 
culate hjorbei die 00, anf. Nach dem Tere cen 0 =H 


die Monge der ausgeatmeten CO, pie Me™ 1 


($85) Motto ©” or Untersuchung des respirator 


meter i 
Probe davon schlieBlich analysiert. — Rei der von Zunts 
atmet ebenfalls die Versuchsperson durch ein Mundstick 
wird in einer Gasuhr gemessen und withrend der ganzen 
‘aatmungsiuft gesammelt und diese xam SchluB analysiert. 
Jaquet hat einen Respirat rat konstruiert 
in einem groBen Inftdicht schlieBenden Raume aufhiilt, = 
Mare gemessen werden kann. Von der durch den ¥ 
ithnlich wie bei dem Zunts-Geppertschen Verfahren, © 


Fig. 00, 





Schoma des Respirationsapparates you © P 


sammelt; im Loufe eines 2dstindigen Versaches werden + 
auch der Verliuf des Gusweehsels wihrend der Versuche + 
vereinigt somit die Vorzige der Methoden 1 and I mite) 


85. Zusammensetzung und E 
der atmosphiirischen | 


1, Die trockene atmosphiirische Luft e 


Gasurt Volumenpn 
Sauerstoft 20,94 
Stickstoft 78,40 |, 
Argon, Krypton, Neon 0,68 
Kohlensiture ne 


100,00 


1887) YORANwwee- oe AUST ONeSlutt, Dor respiratorische (notiers t, 


4. Die Ausatmungsluft ist bei rahigem Atemholen mit Wass 
gesittigt (Galeotti"’, Loery u. Gerhartz™). Infolgedessen wird 
selndem Wassergebalte der atmosphirischen Luft der 
verschieden grobe Mengen Wasser durch die Lungen entleeren. Bei s 
Atematigen sinkt der Prozentgehalt der Ausatmungsluft an Wasser. - 
die Temperatur der Umgebung hat einen Kinflub auf die Gr 
Wasserabgabe: bei 15°C liegt ein Minimum, von hier abwiirts st 
Abgabe miifig, aufwiirts jedoch steigt sie rasch (Rubner™). 

5. Die Ausatmungsluft hat eine ziemlich hohe Temperatu 
oie u. Gerhartz** betriigt die Temperatar der Monisuea 
zwischen 32 und 35,259, die der Nasenansatmungsluft ist niedri 
Mittel 32.2. Die Werte schwanken mit der Atemtiefe und dem . 
lumen nur in sehr engen Grenzen. 

6. Nach Regnault u. Reiset sollte N in sehr geringen Menger 
Ausatmungsluft vom Kérper abgegeben werden; dieser Befund 
anderen Autoren bald bestiitigt, bald bestritten worden. Nach den 
Untersuchungen von Krogh? u. Oppenheimer®® kann es keinem 
unterliegen, daG dieser Befund auf Versuchsfehler zuriickzufihren is 
N wird vom Kérper durch die Atmung nicht abgegeben. 

Nach Versnehen yon Magnus* wird von der Iebenden Tunge weder Am 
resorbiert, noch aus dem Blute (in welches es injiziert worden war) in die Ausat 
abgegeben. Nach Haber® findet jedoch eine Aufnahme von Ammoniak aus den 
in das Blut tatsichlich statt; daB eine Abgabe aus dem Blate in die Alveolen nie! 
win nicht etwa durch eine Undurchgingigkeit der Alveolarwand fiir Ammoniah 
sondern darch die anBerordentlich grobe Absorbierbarkeit des Ammoniaks in Was 

7. Geringe Mengen Wasserstoff und Sumpfgas (CH,) — 
vom Darm aus resorbiert, werden in der Ausatmungsluft ausges 

Tacke® find beim Kaninehen pro Stunde und Kilogramm Korpergowh 
bis 3.9 cm® Wasserstoft nnd 1,214—4,24 om Sumpfigus. Beim Merde hestimmten 
Lehman den Gebolt der Exspirationsiaft an Waswerstoff xu 0/013"), und an Sur 
0,088"), im Mittel. Bei Wiederkiiuern sind die in der Exspirationsluft enthaltene 
Wasserstoff nnd Sumpfgas wesentlich hiher; Henneberg w. Pfeiffer ® fanden beim 
dal 73%, des gesamten abgegehenen Kohlenstofts als Sumpias ausgeschieden wi 

Die durch Kiilte kondensierten Wasserdiimpfe der Exspirationslaft mane 
tan) ziftig (Brown-Séquard u.d’Araoneal®) durch die ¢ 
(RK. Wurtz"), oder von Ammoniak, welehes sich als Ze 
produkt in hohlen Zibnen oder in kranken Laftwegen bildet (Formiének*), 









87. Der respiratorische Quotient. 


Wenn der in der Atmung aufgenommene O einzig und alle 
verbraucht wiirde, um den C der Nahrungsstoffe zu CO, zu verl 
so mil6te das Volumen der abgegebenen OO, gleich dem Volumen 
genommenen © sein (gleiche Volumina O und CO, enthalten gleie 
Mengen ©). Da aber mit dem aufgenommenen 0 auch noch and 
standteile der Nahrang verbrannt werden (H zu H,O, N zu H 
5 zu Schwefelsiiure usw.), so wird unter gewbhnlichen Verhiiltnis 
Volumen der ausgeatmeten CO, kleiner sein miissen als das des au 
menen O, das Verhiiltnis o oder ,der respiratorische Quotient 
Kleiner als 1. Wie gro der respiratorische Quotient im speziell 
ist. hiingt in erster Linie yon der Art der im Kérper verbre 
Nahrangsstoffe ab. Die Kohlehydrate 2B. enthalten moet ‘ 
viel 0, als zur Verbrennung des H ndtie, it, os wir’ mith 

ton Wit 3 ii aller cingeatmete 0 
Koblehydrate im Kirper verbrenne® “8° a 


assy) a “ Tespiratorischen (aswech#els, 


bedingt wird. (Uber die Berechnung der gesamten Energieprodukti 
dem respiratorischen Gaswechsel ygl, § 195.) 

Der Grundumsatz, bestimmt im nlichternen Zustande, etwa 12S 
nach der letzten Mablzeit, bei yollkommener Muskelerschlaftung un 
meidung aller Kérperbewegungen, betriigt nach Magnus-Leoy und 
bei gesunden Miinnern von 60—70 kg Gewicht im Mittel: 










pro Minute 





Sauerstoft Kobleasiure 











em ’ 




















pro Lky | 8,6 nis} 0051 
Korpergewieht 37 0,0053 








fir den ganzen 





«| 0,815 
» 220bis| OF 
Kirpes h His a1 A 
(60-70 ky) 250 0.858 200 | ggg | Liter Liter 


























Benedict uv. Cathcart’ fanden in eebr sorgfiltig ausgefabrten zahlreichen Vej 
die sich Gber die Zeit von 5 Monaten verteilten, bei einem Manne von 64,5—68 ky 
gewicht die folgenden Werte fir den Grundumsatz pro Minute und ky Korperg 
‘Sanerstoif 3,38—4,09 cm*, im Mittel 3,87 em; Kohlensinre 2,86—8,49 em?, im Mittel 3 

Der Granduimsatz ist fiir ein und dasselbe Individum unter gt 
Verhiiltnissen ein annihernd konstanter Wert (Léwy %), Bei verschii 
Individuen welchselt er dagegen in gewissen Grenzen und kann av 
demselben Individaum durch anbere Einwirkungen Anderungen erl 

Bezioht man, wl es gewdhnlich geschieht, den Gaawechsol auf dic Kinh 
Korpergewichts, so erbilt man bei verschiodenen Individuen schwankende Wer 
artige Abweichungen vorschwinden dagegen fast villig, wenn man den Gaswechsel 
auf die Kinheit der Korperoborflache (vgl. $202). In 7 Versuchen an Miinnorn 
nach Magnus-Lery w. Falk’ pro Minute und pro 1m? Obortliche im Mitte! die 
stoffinfnahme 118 em', die Koblonsinrenbgabe 93 em? (Grundumsata). 

Die absolute Muskelerschlaffung und Muskelruhe, w 
bei der Bestimmung des Grundumsatzes von der Versuchsperson absiy 
eingehalten werden mu$, kann nattirlich immer nur fiir yerhiiltnis 
kurze Zeit bestehen; sie ist daher wohl zu unterscheiden von der ge 
lichen ,Bettrube*, bei welcher leichte Bewegungen und Muskelspann 
nicht ausgeschlossen sind, und noch viel mehr von der ,Zimmerruhe*, 
Zustande ruhigen Sitzens und leichter Beschiiftigung ohne direkte A 
leistang. Johansson® schied pro Stunde CO, aus bei absoluter Ruhe 
bei Bettruhe 24,8, bei Zimmerruhe 38,1 g. 

Zu dem Grundumsatze kommt nun hinzu der Leistungszuw 
der im wesentlichen bedingt wird durch die Titigkeit der Musku 
die Nahrungsaufnahme und die Einwirkung der Umgel 
temperatur. 


1, Muskelarbei 5913), — Schon ganz geringfligize y 
bewegungen me Marke $2! ae erhihen den Umsatz merklich; 
dery elspanninge p hoher als beim Liegen (Johan 


erbrauch beim Stehen und Sit#” 


Biches cvs FOSPITALOTISCHEN UnSWeENSeIs. 


dynamische WirkU"g der Nahrangsstoffe. — Pir die prakti 
Erntthrungsverhiltnisse des Menschen, bei denen in der gem) 
Kost das Eiweié gegentiber den N-freien Nahrungsstoffen zurticktri 
jedoch dieser Einflab der Nahrung auf die Zersetzungen von keine 

Bedeutung, Rubner' yeranscblagt den vollen Tageswer 
Energieverbrauchs des Menschen bei mittlerer Kost nur um 7—8%), 
als den Hungerverbrauch. 

Die spexitisch-lynamische Wirkung der Nahrungsstoffe kann nach Rubner* 
anf die Verdauungsurboit im Sinne von Zuntz? xuriiekgofibrt werden (vgl. Heil 
‘Reber nimmt zur Erklirung der Brécheinung an, daQ bei der Zersetzung der Na 
stotfe im Korper Energie in zwei verschiedenen, fiir den Kirper nicht gloiehy 
Formen auftritt, nimlich Wiirme, welche als Kraftquelle for die Lebensvorging 
welter benutzbar ist, und biologisch ausnutzbare Knergie; der Betrag der biolagise 
Yerwertharen Wirme ist besonders gro bet der Zersetzung der Kiweibkirper. Die +p 
dynamische Wirkung ist eben bedingt durch denjenigen Teil der Energie der Nahrun 
der bei der Zersetzung sogleich als Warme auftritt: bei abundanter Kmahrang, bv 
aber bei hoher Unigebungstemperatur kann diese Wirmo tiberhaupt nicht mehr 
weeks dos Kirpers verwandt werden, sic wird auf dem Wege der physikalischen 
regulatinn (s. unten) nach auBen abgegebon, so dal dio spexitisch-dynamische Wirku 
lesen Umstinden voll in Erschoinung tritt. Bei niedrigen und mittleron ‘Temperatn 
gegen uni bei einer den Bedarf gerade deckenden Nahrangseufuhr kann diese Wit 
‘Aufrechterhaltung der Korpertemperatur yerwandt werden, es wird dann eben + 
sprechender ‘Teil bei anderen Zersetzungon cingespart (Com pensationstheori 
diese Weise tritt unter diesen Verhiltnissen die spezitisch-dynamische Wirkung nic 
oder dberhaupt nicht in die Erscheinung; die Nahrungszufubr verliuft dann obne B) 
der Zersetuungen, 


3. Die Temperatur der Umgebung (vgl. § 200). — Zu untersel 
ist das Verhalten der Kaltbliiter und Warmbliiter. 

Die Kaltbliiter (wechselwarme, poikilotherme Tiere) — 
ihre Korpertemperatur der Umgebungstemperatur an; bei héherer ‘I 
ratur der Umgebung steigt ihre Eigentemperatur und damit zuglei 
respiratorischer Gaswechsel und umgekehrt (H. Schulz 1), 

Die Warmbliter (gleichwarme, homoiotherme Tiere) 
halten bei weiten Schwankungen der Anbentemperatur ihre Kérper! 
ratur konstant. Erst bei Einwirkung extremer ‘Temperaturdifferenze) 
unter pathologischen Bedingungen undert sich die Kigentemperat 
Wanmbliiter; in diesem Valle verhalten sie sich wie Kaltbliiter: bei st 
Sinken der Kérpertemperatur findet eine betriichtliche Verminderm 
CO, -Abgabe statt (Piliiger%%, Velten*, Erler 7) — bei Steigernr 
Korperwirme (auch im Fieber) eine Erhéhung der CO,-Abgabe (C. 1 
u. Sanders-Ezn*), — Solange dagegen die Anderangen der Umge 
temperatur keine ganz extremen sind, bleibt die Kirpertemperatur der ! 
Dliiter anniihernd konstant. Dieses Resultat kann nun auf zweifache 
erreicht werden: 

1. durch physikalische Wirmeregulation. Dabei blei 
Wirmeproduktion ganz unveriindert, ein Kinflué der Umgeb 
temperatur auf den Gaswechsel wird also ganz vermib 
KGrpertemperatur wird vielmehr dadurch konstant erhalten, dab de 
derangen der Umgebungstemperatur entsprechend die Bedingunge 
Wirmeabgabe verindert werden, z. B. durch Veriinderungen der 
der Hantgefiibe, der Puls- und Atemfrequenz, der Kérperhaltung, ¢ 
auch willkiirlich durch Anlegen wiirmerer oder diinnerer Kleidung 
Die Wirmeabgabe wird anf diese Weise trotz den Veriinderungen di 
gebungstemperatur stets konstant erhalten. Diese Art der Wiirme 
lation jst beim Menschen die vorherrgchende. 








6 
(sev "elle des respiratorisehon Gaswechsels. 


aa Bor: Kiirperoberiliches, Yorhalt Sich abweichend von dem iilterer Kinder; in de 
ee Vagen ist er ofr 11 driger als der des Rrwachsenen, steigt dann any 
Gen Aer Eirwachsenen gleich, erreicht aber erst frihestens am Ende des 3. Monats d 
‘wiz wa spiliteren Kindesalter. 


5. Das Gesehlecht. — Bei gleichem Gewicht und gleicher Kérpe 
fiche haben Erwachsene beiderlei Geschlechtes denselben G 
umsatz (Magnus-Levy u. Falk”). In der Pubertiitszeit fanden $ 
u. Tigerstedt® die CO,-Ausscheidung der Knaben bei Zimmerruh 
$1—56/, hoher als die der Madchen (stiirkere Bewegung der Knal 
Magnus-Levy u. Falk® fanden O,-Verbrauch und CO,-Ausscheidun 
Knaben nur um 6—7°/, hiher als bei Midehen. — Im Greisenalte 
nach den letzten Untersuchern der Sauerstoflverbrauch bei Miinnern 
grifer als bei Frauen. 

Durch die Menstruation wird die Intensitit der Oxydationsvorginge niy 
einiluBt (1. Zunts'), Wihrond der Graviditiit ist der Sanerstoftverbranch pro Kil 


Gewicht der Mutter und dex Kindes unveriindert oder hichstens um $—4°), 
( Hasvelbatch °), 


6. Schwankungen zur Tages- und Nachtzeit. — Wuhren 
Schlafes ist der Gaswechsel natiirlich geringer als im wachen Zu: 
wegen des Vehlens der Muskelbewegungen, der Nahrungsaufnabme 
Sondén u. Tigerstedt** fanden im Mittel fir das Verhiiltnis der CO, 
seheidung wiihrend des Schlafes zu der wihrend des wachen Zust 
den Wert 100:145, An sich hat der Schlaf keinen Einflu6 av 
Umfang der Verbrennungsprozesse im Kirper; der Umsatz wihren 
Sehlafes ist ungefihr derselbe wie der Grundumsatz bei absoluter M 
ruhe. Benedict u. Cathcart geben allerdings im Gegensatz hierz 
da® nach ihren Versuchen die Verbrennungsvorgiinge im festen S 
niedriger waren als im wachen Zustande bei vollkommenster Muske 

Im Laufe des Tages zeigt die O-Aufnahme und CO,-Abgabe 
Hangernden und bei Ausschlub wechselnder Muskeltitigkeit) keine w 
lichen Schwankungen (Rubner™, Magnus-Leoy™, Johansson **): bei 
nahme von Nahrung bedingt nattirlich jede Mahlzeit eine entspree 
Steigerung. 

Im Winterschlafe (vgl § 206), — in welehem die Korpertemperatur stark 
gesotat ist, die Nahrongsanfnahme nnd Muskeltitigkelt villig unterbleibt, selbst die 
bowegangen ganz suspendiert oder doch anBerordentlich verlangsamt sind, findet eine 
Herabsetuung des respiratorischon Guswechsels statt. Am stirketen erniedrigt ist d 
Ansscheidung: nich Pembrey™* kann dieselbe hei Myoxus anf "fj, der Menge sink 
im wnchen Zustande ausgeschieden wird. Die O-Anfnahme wird ebenfalls, aber in | 
ringerem Grade orniedrigt, so dal der respiratorische Quotient bis auf 0.23 sinker 
Beim Erwachen aus dem Winterschlnfe steigt der respiratorische Gasweebsel in kur: 
fudeutend; der respiratorische Quotient wird anf 0,7 erhiht (vgl Nagai), 


7. Der Aufenthalt im Hellen — sollte nach tilteren Untersuch 
eine direkte Erhdhung des respiratorischen Gaswechsels zur Folge 
gegenitber dem Gaswechsel bei Aufenthalt im Dunkeln; es diirfte sie 
bei aber um eine indirekte Rinwirkung durch Anregung zu Mus) 
wegungen gehandelt haben. Wird der Einflué weehselnder Muskeltat 

chaltet, so erhdht weder die Einwirkung des Lichtes auf die. 
Wane noch die Bestrahlung des ganzen Kirpers mit Sonne 

Wolpert'**) den respiratorischen Gaswechsel. 


8. Zahl und Tief —. haben auf den Verbr 
von O und die Bildung der Cre ale0 auf die Verbrennung 


ate - o> MasHUSLAUSCHES am Uer Lage. 


fangt, die erste Hulfte (aus den gréSeren Luftkaniilea stammend) w 
©O, enthilt (3,7 Vol-Prozent, Vierordt '8) als die zweite Hiilfte (5, 
Prozent). Diese Ungleichheit des Gasgemenges in den verschiedenen! 
des Atmungsorganes ruft selbstverstiindlich eine fortwihrende Gasdil 
zwischen den verschiedenen Schichten heryor, und ebenso endlich 2w 
den Larynx- und Nasenhhlen-Gasen und der iiuberen atmosphiirischen 
und zwar wird die CO, bestiindig aus der Tiefe der Lungenbliischen 
die tufere Luft, hingegen der O der Luft in das Gasgemenge der Ly 
alveolen diffundieren. Unterstiitzt wird diese Diffusion bei Ausfa 
Atembewegungen durch das bestiindige SchiitteIn der Atmungsgase i 
der kardiopneumatischen Bewegung; im Winterschlafe mu 
diese Weise einzig und allein der Gaswechsel innerhalb der Laungen 

halten werden (vgl. 8. 135). Fiir gewéhnlich ist jedoch dieser Mee 
mous ftir den AtmungsprozeB unzureichend; es kommt vielmehr der dur 
Atembewegung veranlaite Luftwechsel hinzu: hierdurch wird in d 
meisten nach den Ausflihrungsréhren liegenden Teile der Lungen 

sphirische Luft eingebracht, aus welcher und in welche die Diffo 
strémung von O und CO, wegen der gréSeren Spannungsdifferenz 
Gase um so lebbafter vor sich geht. 

Von der cingeatmeten Luft dringt immer nur ein Teil bis i 
Alveolen; ein Teil verbleibt in den Bronchien, der Trachea, Mund- 
Nasenhihle (sog. ,schiidlicher Raum“), ohne an dem Gasanstausel 
zunehmen. Bei der Ausatmung mischt sich die Alveolenluft mit der 
sphiirischen Luft des ,schiidlichen Raumes* und wird so zur Ausatn 
Taft. Aus der Gréfe des schiidlichen Raumes (140 em, vgl. 8. 183) 
Grobe eines Atemzuges (500 cm, vgl. 8. 182) und der Zusammenst 
der atmosphitrischen und der Ausatmungslaft kann man die Zusam 
setzung der Alyecolenluft berechnen; nach Bohr enthiilt di 
14,6°/, O und 5,6°/, CO,, entsprechend einer Partialspannung yon 
baw. 40 mm Hg (Gesamtspannung nach Abzug der Tension des W 
dampfes von 50 mm = 710 mm). 

2. Gasaustausch zwischen der Alveolenluft und dem | 
der Lungencapillaren, Uber die Art des Vorganges, durch welcl 
der Lunge der Sauerstoff aus der Alveolenluft in das Blut aufgenor 
die Kohlensiiure aus dem Blute in die Alveolenluft abgegeben wird, | 
sich zwei Anschauungen gegentiber. Nach der einen handelt es sic 
bei um einen rein physikalischen Vorgang nach den Gesetzen de 
fusion, wonach jedes Gas von dem Orte hiéherer Spannung nacl 
Orte niedrigerer Spannung wandert. Nach der anderen Anschanung da 
fibt die Lunge cinen spezifischen Einflu® darauf aus in der } 
da6 sie gleichsam wie cine Drlise die Gase secerniert. 


Methode der Untersuchung. Pfliger u, Wolffberg" haben in der fo 
Weise die Spannung der Gase im Blute der Lungencapillaren, resp. in der abges 
Alveoleninft bestimmt. Bei gesffacter Trachea wird einem Hunde ein elasti 
Katheter (Lungenkatheter, Fig. 61) in den zum linken uateren Lungenlappen fl 
Bronchialast eingeftibrt, Um denselben in dem letzteren au dichten, wird um den K 
eine yon thm durchbohrte Gummiblase (mittelst kommunizierender Gummiballonpu 
anfgebliht, so da nun ans dem augehdrigen Lungenterrain keine Loft neben dom K 
vorhei entwaichen kann, Der Katheter ist an seinem AusfluBende vorerst versehlosse 
Hund atmet selbstandig und méglichst rubig. Schon nach 4 Minuten hat 1 
Alveolenluft des abgesperrten Lungenbezirkes vollig mit den Blutgasen ausgeglichen. 
daber nunmehr ans dem Katheter (bei b) die Langenluft Be ciate one) Fra 
atiet die Spannung yon OO, und Qin ihr augleich wnt indirektem Were die 


befden Gase in dem Blute der Lungeneap* os 





[8905 Die Hantotin wemgre 


Das Hb des Blutes findet in den Lungencapillaren reichlichen 
her bildet sich bie? "nter dem hohen Partiardruck des O die che) 
Verbindung des Oc-Hb. Auf seinem Wege durch die Capillaren des | 
Kreislanfes kommt dieses in Berthrang mit den O-armen resp. O-frei 
weben: es dissoziiert sich das 0,-Hb, sein O fillt den Geweben zu 
mit gasfreiem oder reduziertem Hb kommt das Blut zum rechten 1 
und von da zur Lunge zurlick, um aufs neue O aufzunehmen. 

Die CO, trifft das kreisende Blut am reichlichsten in den Ge 
an; der hohe Partiardruck der CO, an dieser Stelle bewirkt, dab si 
betreffenden Blutbestandteile mit CO, zu einer chemischen Verbindun; 
einigen. In den Lungen jedoch, in welchen ein niedriger Partiardruck fi 
herrscht, dissoziiert sich das Gas und die CO, gelangt zur Aussche 


90. Die Hautatmung (Perspiration). 


Methode. — Bei cinem in der Kammer eines Respirationsapparates sich beti 
‘Menschen oder Tiere wird der Lungengaswechsel durch ein Mundstick und eine da 
seblicBende Robrieitung nach anBen abgeleitet, so dal mit der Luft des Reapirationsay 
nor die Haut des Versnchsobjektes in Verbindung steht. Weniger korrekt ist es, den 
Kopf anGerhalb des Kastens xo lassen und den Hale in der Kammerwand einzudich 
Von cinzelnen Kirperteilen, zB. yon einer Extremitit, kann man die Hautatmung 
suchen, indem man sie in einem geschlossenen Zylinder cindichtet, Abnlich wie d 
im Methyxmographen ruht (§ 56). 


Das respiratorische Organ der Haut sind die reichlich mit Blatg 
versehenen Kniueldrtisen. Der Korper erleidet durch gasftirmige Ab 
yon der Haut im Laute des Tages einen erheblichen Gewichtsverlus 
aber der Hauptsache nach anf die Abgabe von Wasserdampf kc 
daneben findet auch eine geringfigige Kohlensiureabgabe und S 
stoffaufnahme statt. 

Die Wasserabgabe ist nattirlich wechselnd nach der Temp 
und Feuchtigkeit der umgebenden Luft. Fiir 24 Stunden betriigt sie 
Atwater u. Benedict *° 9359. Vir 1 Stunde fand Schwenkenbecher* 
mittlerer Temperatur und Feuchtigkeit 28 9, Wolpert*** hei 25° und 
bis 34°, Feuchtigkeit 62 g. 

Die Kohlensiiureabgabe betriigt fiir 24 Stunden 8-109, ali 
ea. 1°, der durch die Lunge abgegebenen Menge. Steigerung der | 
bungstemperatur vermehrt die CO,-Abgabe, sie betriigt bei 29°—30° 
in 24 Stunden, bei tiber 33°C 20g (hier beginnt auch der Schwe 
brach), — bei 384°C 27,59 CO, (Schierbeck'**). — Vermehrte 
seheidung wird auch durch lebhafte Muskeltitigkeit bewirkt. 

Eine Sauerstoffaufnahme durch die Haut ist zwar nachgev 
worden; sie ist aber sehr geringftigig, Im Hichstfalle macht si 
der Sauerstoffaufnahme durch die Langen aus (Zilzer***), 

Abgabe von gasformigem N oder NH, durch die Haut is 
hanptet worden, kommt aber in irgendwie betrichtlichem Mabe nich 


Bei Warmbliitern mit dicken, trockenen Epidermoidalgebilden ist der entar 
weehsel noch geringer uls beim Menschen, — Prdache und andere Amphibien m 
durchfouchteter Hant zeigen dagegen eine viel hervorragendere Hantatmung. Die Haut 
ope aller ahgeschiedenen OO,, bel Winterfrcen och meh r (lg ee 
ein wichti orange. Bintauchen in Ol totet diese ‘Te 
als die Ge . Steet als die om ‘wird beim Frosh durch die Haut 
lich die lung der Lungen. Nach Krogh veatoffantnahme durch die Langen 
hlensiure abgegeben, wiihrend die 5° " 


'S-Rosomann. vhesiolow'a ys son 





Landy 


($92) Atmung im abgesperrten Ranme, 


verwandeln sic in uneeAibte Redoktionsprodukte. Pankrea# und Subbmicesris wi 
gar nicht reduaierend ("lich **), (Dig Modifikationen der Reaktion eiadiarten , 
‘and Fialo™,) 

In vielen tierisebe? Organen und Geweben sind Fermente aufigefunden worden, 
oxydierende Wirkungen #USiben: Oxydagen (vgl 8.19, 4, Battell’ a. Stera™). 
dinge Oxydasen mit der physiologischen Verbrennung in dea Geweben irgend etwas 
haben, ist aulerordentlich 2weifelhatt. 

Im Blute — findet, wie in allen Geweben natiirlich ebi 
O-Verbranch und CO,-Bildung statt. Dies beweist schon die Tatsach 
entleertes Blut allmihlich O-irmer und CO,-reicher wird (S. 94); 
der Umstand, dali im O-freien Blute Erstickter, und zwar in den 
Kiérperchen (Afonassic/*") immerhin, wenn auch nur geringe M 
reduzierender Stoffe sich finden, die nach O-Zutritt sich oxydieren. 
dings ist dieser Gaswechsel gegeniiber dem in allen tbrigen K 

eben nur sehr gering. Dab auch die Gefibwiinde, zumal 
ihre Muskeln, © verzehren und CO, produzieren, ist selbstyerstii 
wenn auch dieser Prozei nur so gering ist, dai das Blut auf seiner ¢ 
arteriellen Bahn keine wahrnechmbare Varbenveriindernng zeigt. 

Lavoisier hatte den gesamten Gaswechsel, O-Verbranch und (( 
dung, in die Lungen verlegt. Dies ist nach dem oben Gesagten unzutri 
Nattirlich haben aber auch die Lungen als lebendes Gewebe am Gasw 
einen gewissen Anteil. Nach Bohr u. Henriques’, Pittter?** soll in der 
sogar ein Sauerstoffverbrauch und eine Kohlensiiureproduktion stattl 
die durebsehnittlich etwa ein Drittel des gesamten Stoffwechsels bv 
doch wird die Beweiskraft ihrer Versuche stark bestritten (Loe 
Zuntz*, Evans u. Starling”), 


92. Atmung im abgesperrten Raume 


oder bei kiinstlich verindertem Gehalt der Atmungsluft 
an O und CO,. 


Die Atmung im abgesperrten Raume hat zur Folge: — 1. d 
mihliche Verminderang des O, — 2. die gleichzeitige Vermehran 
©O, — und 3. eine Verminderung des Gasyolumens. Ist der Raw 
miaGig groB, so verzehrt das Tier den O fast vollstindig (S. 94 
Blut wird fast O-frei und unter Erstickungskriimpfen erfolgt schl 
der Tod. Dieser ist also bedingt durch O-Mangel. 

In gréferen abgeschlossenen Riumen kommt es eher zu 
reichlichen CO,-Ansammlung als zu einer das Leben bedrohenden ( 
minderung. Da die CO,-Ausscheidung aus dem Kérper nur erfolgen 
wenn die CO,-Spannung im Blute gréfer ist als in der umgebender 
so wird mit zunehmender CO,-Ansammlung in dem abgeschlossenen | 
alsbald ©0,-Retention, ja schlieBlich CO,-Zuriicktritt in den Kérper 
finden. Dies erfolgt zu einer Zeit, in weleher der O zum Leben noel 
reicht. Es tritt daher hier der Tod direkt durch CO,-Vergiftung ein 
den Erscheinungen kurz dauernder Dyspnoe, der sich Betiéiubun; 
Abkiihlung anschlieBen. So starben Kaninchen, nachdem dieselben 
Teil der nachweisbar vorher yon ihnen ausgeschiedenen CO, zurile! 
genommen hatten (W. Miller %7*), 

Ernouerung der Luft in Wohnriumen, Ventilation. In Gberfillten 
stelet zuniichst der (0,-Gehalt; 0. Pettenkofer"® fand don normalen Gehalt d 


(=0,5%,,) gestaigort im behaglichen Wohnzimmer aut 0,o4—0/ in schh 
al Krunkenstaben aut 2, ON i ask eer ear a cht die’ 00, of 
anf 4.99 =F [go = mn st ‘Anbordings sind os nicht die CO-Me 


oy — in Schulzimmern aut V2 oo" u 





1898) Atmen fremdartiger Gase, 


man den CO,-Gehalt der einzuatmenden Luft, so 1 
die Atembeweg@mge" Zu, es tritt Dyspnoe ein. Eine Luft von 0,1° 
bezeichnet v. Pettenkofer als ,schleehte Luft*, doch riihrt das i 
selben empfundene Unbehagen (z. B. in Uberfiillten Ruiumen) mebr ¥¢ 

tmeten widrigen Dinsten unbekannter Natur, als yon der CO, 
her. Luft mit 1°/, CO, erzeugt merkliches Unbehagen, bei 10°, wit 
Leben ernstlich gefiihrdet, bei noch héherem ©O,-Gehalt (25/,) tr 
Tod unter Kriimpfen ein (Albitzky™*), 

Bietet man Tieren cin der atmosphirischen Luft iihnliches Gasgemenge, in > 
N durch H ersetat ist, so atmen sie vollig wie normal; der H dea Gemisches erleidk 


penpengwerte Mongenverinderung, — Zunahme oder Abnahme des N in der Luft b 
einfach eine griBere oder kleinere Absorption desselben seitens der Korpersiifte (5 


93. Atmen fremdartiger Gase. 


Kein Gas vermag ohne hinreichende O-Beimischang das Leben 
halten, es tritt vielmebr ohne © bei allen, anch an sich yollig unsehiidlichen 
Gagen sehnello Erstickung (in 2—3 Minuten) ein. 


1, Véllig indifferente Gase — sind N, H und CH,. 


IL Giftige Gase. 

a) O-verdrdingende: — 1) CO (siche $21). — 2) CNH (Blausiare) verdr 
© ans dem Hb, mit dem es cine stabilere Verbindung eingeht, wnd titet tinBerst 
BlatkGrperchen mit Blaustiure beladen, verlieren die Fuhigkeit, Wasserstoffsupero 
Wasser and © 2u_ zeraetzen, 

b) Narkotinieronde: — 1) CO,. Vgl. § 92. — 2) N, 0 (Stickoxydolgas) ein 
(mit '), Vol. © yermischt), bewirkt in 1*),—2 Minuten einen schnell vortbergehen 
sondera Instigen Ranschaustand (Lastgis*), welchem eine vermehrte CO,-Ansse 
folgen soll. — 3) Oxonisierte reine Luft wirkt ahnlich: auch sie erzengt angenebn 
gong, dann Schlifriekeit und rasch voribergehenden Schl: 

e) Reduzierende: — 1) HS (Schwefelwasserstoff) entzieht schnell d 
thrveyten allen O, bierdurch tritt schon sehleuniger ‘Tod ein, beyor noch dae Gas ej 
Anderang des Himoglobins unter Bildung yon Suiphhisnoglobin bewirken kann (3. 6 

2) PH, (Phosphorwasseratoff wird im Blute xu phosphoriger Sire und 
exyiiert enter Zerseteung des Hb. 

B) AH, (Arsenwasserstoff) nnd — SbH, (Antimonwasserstoff) 
dem Phosphorwasserstott unilog, lassen Uiberdies das Hb aus dem Stroma anstreten, 
Nb-reiche Ansscheidungen erfolgen. 

4) ON, (Cyangas) wirkt O-entaichend und weiterhin daa Blut zersetzend. 


IL. Irrespirable Gase — konnen dherhanpt nicht goatmet werden, da bein 
in don Kehikopf reflektorischer Stimuiritzenkrampf entstebt, Gewaltsam in die 1 
gebracht, bewirken sie lebhafte jindungen and weiterhin Zerstorungen und d 
Ks sind Chlorwaaserstoffiure, — ewasserstofisiinre, —~ schwetlige Siure, — Unters 
siure, — salpetrige Siure, — Ammeoniuk, — Chlor, — Fluor, — Jod, — Brom, 
verdiinntes Ozon, — reine CO, 












94. Normale Schleimbildung in den Luftwegen. 
Der Auswurf (Sputum), 


Die Sehleimhaut des Respirationskanales ist von einer diinnen 
Schleim bedeckt. Diese verhindert mechaniseh durch Abhaltung di 
wohnlichen Reize der Luft und des Staubes eine weitere Sehleimbil 
Letatere erfolgt nur insoweit, als die Verdunstung sie zum Ersatz 
wendig macht. Im allgemeinen tritt mit vermehrter Blntdurchstrémm 
Trachealschleimhant auch yermehrte Sekretion cin. Einseitige Ni 
durehsehneidung bewirkt Ritung dieser Seite und. stirkere Absond 


; . kung des Bauches) wird die Sch! 
Boim Rintritt von Hrkdltung — (Bisbee der Absonderung. tiefrot. 


Vollig blaB, dann unter sehr starker ¥ 





| 1896] ares, Literatar (jf 1U-vo), 
| 

| ams dem Kirper entfernt Werde, zugleich mit dem ausgeatmeten Wasser, Von G 
i Esperimente Uber die Mechanik der Atmune her: ie beable, 
| Laangen passiv den Bewegungen des ‘Thorax folgen, daB das Zworebfell de 


‘ien, 

m Pneumothorax beide Langen zusimmensinken (360m. Chr.). ~ 
ua beschreibt bereits dic kiinstliche Atmung zur Wiederbelebung und aur A) 
eo Malpight antersuchte 1661 den Bau der Den Mech 
erklirte xuerst am griindlichsten Joh. Alf Borelli (+ 1679). 
eisen entdeckte 1808 die Muskulatur in den Bronchien bis in ihre feineren Y 

deren Contraction auf Reix schon Varnier 1779 bekannt war. 
Die chemischon Vorginge — bei der Atmung ahnte schon Mayow 1 
‘et vita jisdem partienlis aéreis sustinetur.* Dennoch konnte genauere Einsi¢ 
wonnen werden nach Entdeckung der einzelnen in Betracht kommenden Gase; 
ean Helmont (+ VG44) entdeckte die CO,, or fand, daB die Luft durch die / 
versehlechtere, aber erst Black 1757 ermittelte die Ausscheidang der CO, dareh 
= 1774 entdeckten Mriesttey und Scheele den O; Lavoisier fand 1775 den 
mittelte xugleich die Zusammensetzung der atmosphirisehen Luft. Derselbe For 
dann auch die CO,- nod HyO-Bildung bei der Atmung als das Resultat einer |} 
im Innern der Langen dar, J. Ingenhousz entdeckte (1779) die Atmung der Pf 
nahme der (0, und Abgabe des O darch dieselben; daB dieser exhalierte O ar 
stamme, fand Senebier 1785. — Vogel und andere wiesen mit Bestimmt 
vendsen Blute, Hofmann und andere O im arteriellen nach. Lavoisier machte 
1789 dic ersten Mitteilungen tber die quantitative O-Aufnnhme und CO,-Abg: 
Atmung. — Volliger Binblick in den Gaswechsel bei der Atmung konnte ers 
werrlen, nachdem durch Magwus (1887) die Gase des arteriellen und yenésen 

gepmmpt und analysiert warden. 


Literatur (§ 70-90). 


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388 
























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18 Ch. 





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Andernng des Drucks und des Snuerstoffigchaltes dee Luft. Berlin 1895. — 174 
A. P. 1903, Suppl, 209. — 175. Benedict u. Higging: A. J.P. 28, 1911. 1. - 
sammenfassende Darstellung: EJ. Lesser: 8. P. 8, 1909, 742, — 177. 1 
Untersuch, ther d. Stoffwechs. d. Muskeln. Berlin 1867. — 178, EB. Pliiger: P. 
251. — 179. H. Aubert A. 26, 1881, 293. 27, 1882, 566. — 180, G. Bung 
8, 1883, 48. 12, 1888, 565. 14, 1890, 318. — 181. FE. Weinland: Z, B. 42, 1 
1906, 87. — 182. Putter: %. a. P. 6, 217. 7, 16. — 183. P. Albiteky: PA. 1 
— 184. Zusammenfassende Darstellung: F. Kalk: E. P.9, 1910, “ 
i e ene Votan te Handbuch der Biochemie, Jena 1910. TI, 1, 7 — 185. Gi 
86. A. Schmidt wu, F. Miller: B. ke W. 1898, T3. — 187. ay 
i 901, 468. — 188. F. Wanner: Diss, Basel 1903. D. A. kM. 75, 100 
189. Fleischer: Sitx.-Ber. d. physik.-med. Sozietit xu Erlangen 1879. — 190. 
B. k. W. 1896, 293, 333, 420, 191. Fr, Maller: % k. M. 12, 1887, 83. 
W. Weber: Mechanik d. mensehlichen Gehwerkzenge. Gottingen 1836. 2. Tei 
— 193. N.Zuntz, A. Loewy, Fr. Maller, W.Caspari: Hohenklima 
Berlin 1906, A. Durig u. N. Zunte: B.Z, 39, 1912, 435, 8. A. 
5. PI, Ae 1903, 612. 194. ve 
= 105. "ber die physiolog. 






















































A. 92, 1902, 1. 93, 
ung des Hihonklimas, Basel 1904. — 196 
a Mitarbeltor: ©. P. 27, 1918, 628. Z. B.61, 1913, 379. — 197, 0. Cohnhetnu. 


D. ALK. M. 140, 1913, 225. MK. 1913, 783. 198, . Laquer: D.A. kM 
189. — 190. E. Abderhalden: %. B. 48, 1902, 125 u. 443. P. A. 92, 190 
200. Morawits: D. m. W. 1910, Nr. 8. — 201. E.Stern: B.k, W. 1914, 720. — 
eckor: Die Bergkrankheit. Berlin a. Wien 1903. — 203, Mosso: Der Mensch un 
alpen. Leipzig 1897, — 204, R. Heller, W.Mager u. H. 0. Schrotter: P.A.@ 
Z.k. M. 88, 1897, 341, 84, 1898, 129. Luftdrack-Rrkrankungen, Wien 1900. — 
Vernon: PRS. 7%, B, 1907, B68. — 206. A. Quincke: A. P,P. 62, 1911 
207. P. Bert: 0.1%. 74, 1872, 617. 7, 1872, 29. 76, 443, 578, 1276, 1493. 77, 
rn rossion barometrique. Paris 1878. — 208. KH. Lehmann: PA. 27, 188 
, 173. — 209. Regnard: C. r. soc. biol. 1887, 265. — 210. A. Jaeger: B.A 
O11. D. Calugareanus P. A420, 1907, 45. 














a sae muneEOnIe und hry Drasen, 


“sentitmlichkeit desienigen KiweiBes bewahren, aus dem sie hervorg 
Sind (Rindseiweib, Pferdeciweib, Pfanzenciweib usw.), sondern das 
Muh abgebaut werden bis zu den cinzelnen Aminosiuren, die al 
‘Keine Arteigentiimlichkeit mehr besitzen. Diese erst werden resorb 
‘us ihnen als indifferenten Bausteinen setzt dann der betreffende Org 
wieder dasjenige Eiwei8 zusammen, welches ihm zukommt. So i: 
den weitgehenden Abbau der Nahrungsstoffe im Darm eine Garant 
geboten, da die Arteigentiimlichkeit erhalten wird. Dringen gh 
artfremde Substanzen in den Kérper ein, so sehtitzt dieser sich 
durch weitere Mafnahmen: Bildung von Antikérpern (vgl. $27 
scheidung durch den Harn usw. — Ganz ebenso wie die Eiwe 
unserer Nahrung wird auch die vegetabilische Stirke im Verdauung: 
bis zu ihren indifferenten Bausteinen, den Dextrosemolekiilen, a 
aus denen dann nach der Resorption der tierische Korper die 
Stirke, das Glykogen, aufbaut. Auch fiir die Fette sind derartige 
sehiede im Aufbau denkbar und wahrscheinlich. 

Die Bearbeitung der Nahrangsbestandteile im Verdauungs: 
ist zuniichst eine mechanische: Zerkleinerung durch den Kauakt. 
schlieBt sich dann die chemische Einwirkung der mit den Verdauun, 

jiedenen Fermente. Diese zerlegen im Wege der hydrol, 
Spaltung die Nahrungsstoffe in ihre einzelnen Bausteine, die zur Re 
geeignet sind. Dabei wirkt entsprechend der Natur der Fermen 
$. 17) jedes einzelne Ferment immer nur auf eine ganz bestimmte 
yon Nahrungsstoffen ein, deren chemischem Bau es angepabt ist. 
tieferen Abschnitten des Verdauungsapparates nehmen auch Miki 
nismen an der Aufspaltung der Nahrungsstoffe teil, doch ist ihr 
samkeit fiir den Menschen und den Fleischfresser von untergeordn 
deutung, von Wichtigkeit dagegen ftir den Pilanzenfresser. 


98. Die Mundhéhle und ihre Driisen. Die Speicheldr 
Veriinderung der Driisen bei der Titigkeit. 


Die Schleimbaut der Mondhihle besteht uns fibrillirem Bindegew 
foinen elastischen Fasern vermengt, und trigt cin vielschichtiges Platten 
— Von den ziemlick reichlichen Blutgefaben liegen die gréberen in der Sab 
wihrend die feineren bis in die Papillen ecindringen, in denen sie entweder 
Maschen oder einfuche Schlingen bilden. — Von den Lymphgefaben liegon die) 
weite Maschen bildenden Stimme in der Submucosa, wiihrend dic feineren, xu einer 
Netawerke gefigten in der Mucosa selbst verlinfen. Za dem Lymphapparate ge 
Balgfollikel oder Lymphfollikel Auf dem Ricken der Zungenwurzel bilden 
eine fast xasammenbiingende Schicht; sie liegen zu mehreren in rundlichen, die Se) 
etwas erhebenden Grappen xusammen. In der Mitte ciner jeden Gruppe liegt « 
tiefung (Fig. 63), in deren Grand Schleimdrisehen ihre Ausmfindung finde 
den kleinen Krater mit Schleimsekret avsfillen, — Die Tonsillen Inssen ix 
denselben Ban erkennen; buchtenartige Vertiefungen, in deren Sinns kleine Schle 
einmiinden, sind von Haufen (von 10—20) Lymphfollikeln umlagert. Festere Bini 
Jagen geben den Tonsillen eine Umbiillang. — Ziemlich zahlreiche haltige 
fasern, — welche von der Submneoga ans hervortreten, verteilen sich in der Sel 
und endigen zum Teil in einzelnen Papillon in Form der Arauseschen Ene 
rechlieher an den Lippen und am weichen Gaumen, spirlicher an den Wangen 
Boden der Mundhohle. Wahrscheinlich finden jedoch die Nerven auch noch ihre Ao 
mitielst foinster Terminalnoduli zwischen den Epithelzellen nach der Cohnheim 
Aansschen Verbreitungsart, 

Die Driisen der Mundhible — liegen a8 Kleine Droachen, sum Te 

Schieimhaut der Mandhohle verstreat, 20m ee ae ee ee a sekre 

groflen Spetcheldrisen. Simtliche Dri” Aer werosen Drowen, in do 
unterschieden: — 1, Die iweigdrise™ 











LSS] 4® Speicholdriisen. 


miindenden, aus vielf@h gewundenen und yereweigten le 
% nea Priisen Mt kleinen, schmalen, mit Sencopeie cafillion Zell 
Blandin-Nuhnsche Dri innerhalb der Zangenspitze besteht aus Schleim- 0 

Hippehen, ist also Cine gemischte Drdse, 

Die Speicheldriisen — zeigen (ebenso wie das Pankreas 
sammengesetzt-tubulésen Typus. Die Ausfithrungsgiinge, a 
und elastischem Gewebe bestehend, flilhren Cylinderepithel. Der 
sxebenden strukturlosen Membran des Acinus ist ein Gesp 
formiger, anastomosierender Zellen eingeftigt (Fig. 64D), Der A 
der Acini liegen zuniichst spaltférmige Lymphriiume an 
welcher erst die Bluteapillaren in netzartigen Maschen verla 
LymphgefiiBe treten im Hilus aus der Driise hervor. 

Die Sekretionszellen — sind verschieden gebaut, je na 
Spe evictas schleimabsondernd (Sublingualis vom Mensche 
aillaris yom Hund), oder eiweifsecernierend (Parotis yom } 
— oder eine gemischte Driise ist (Submaxillaris yom Mensch 

1, In den Acinis der Submaxillaris (Hund) und Sub] 
(Mensch) finden sich zweierlei Arten zelliger Elemente: — 1. die g) 
-Schleimzellen* (Fig.64 B,c) (R. Heidenhain»), welche den Sekré 
zuniichst begrenzen. besitzen eine Membran, sind prall gefiillt und 
einen abgeplatteten, der Acinuswand zugekehrten Kern. Der Zell 
reichlich impriigniert mit Mucin, das ihm ein gliinzendes, stark lichth 
Aussehen yerleiht. Dieses Schleimgehaltes wegen furben sich die! 
durch Karmin fast gar nicht, withrend der Kern den Farbstoff an 
yon der Zelle abgehender Fortsatz schmiegt sich gebogen an die i 

nuswand an; das eigentliche 
Pig. tbs plasma zieht als fadenfirmiges 
yom Kern aus durch die Mueini 
dorch. — 2. Die andere Art d 
Elemente liegt zu einem oder 
halbmondfirmigen Kor 
(B, d) (Gianuezis ~Halbmons 
denhains ,Randzellenkomp! 
Acinuswand unmittelbar an, Ji 
mond besteht aus einer Anzah 
dicht gelagerter, schwer is 
eckiger, stark eiweilhaltiger | 
Kern; sie sind granuliert, dun) 
Schleiminhalt, durch Farbste 
impriignierbar und zeigen zwi) 
Zellen Sekretspalten, 

2. Die Kiweib absondernd 
(Mensch und Siingetiere) en 
eine Art von Sekretionszellen 

tihnliche, im Protoplasma grob 

Fitachensilliges (ecktarecturoten) sere, Wenig durch Farbstoffe tingier 
ingen in don Ausfubrungenang (a) des lenlose Zellen mit zackigem, + 
*owernhy, nash der Atsonderung. flirbenden, central gelegenen, s 
brechenden Kern ohne Kernki 

die Zellen haben Sekretgiinge zwischen sich (2. Miiller®). Dai 
material findet sich in Gestalt von Kornern oder Granula ¥o 
Lichtbrechungsvermigen in dem Protoplasma der Zel\en (Langl 


Landois-Rosomann, PnysioloB: ¥- Avt- 











jang, rr Spoicholrohrou, 9+ 





[s90y Die Innervation der Speicheldetisen, 


sogar die palsatorische Bewegung der Arterien sich bis in die 
t (8. 145) (Cl. Bernhard, Mebr als viermal so viel Blu 
Vene zurlick, das itberdies fast hellrot erscheint und m 
ein Drittel griferen O-Gehalt zeigt als das Venenblut der nicl 
Driise. ‘Trotz dieses relativ hohen O-Gehaltes des Venenblutes y 
absondernde Driise doch absolut mehr © als die ruhende, niin 
mal mehr, bei gleichzeitiger starker CO,-Bildung (Barcroft®), 
Lymphbildung in der Driise steigt parallel mit der Speichela 
(Asher w. Barbira®), 

Im N. facialis liegen zweierlei funktionell verschieder 
fasern: — 1. echte Sekretionsnerven, — 2. gefaberweitern 
Vasodilatatoren. Es ist nicht zuliissig, die Erscheinung de 
etwa als eine einfache Folge der lebhafteren Circulation 4 
(Siehe unten.) 


H. Reizung des N. sympathicus bewirkt eine spirliel 
derung eines sehr dick flissigen, zihgallertigen, fadenzichende 
(Kekhard*), in welchem die spezifischen Bestandteile reichlicb 
sind, namentlich der Schleim; das spezifische Gewicht steig 
bis 1010, Gleichzeitig verengern sich unter Abnahme des ] 
die Gefiife der Dritse, so da6 das spiirliche Blut dunkelbla 
Venen abfiiebt. 

Im N. sympathieus liegen ebenfalls zweierlei fanktionel 
dene Nervenfasern: — 1. echte Sekretionsnerven — und 
verengernde Nerven, Vasomotoren. 


Mit steigender Stirke dea Reizes nimmt die Absonderung und in ibe 
Salze xu. Die Menge der organischen Bestundteile hiingt auber yon der Stir 
auch yon dem Rohbe- oder Erschipfungszustande der Driise ab (Heidenhain "), 
Bintmischnng und die Cirenlationsverhiltnisse in der Drise becintl 
sammensetaung des Speichels (Langley u. Fletcher, Asher u. Cutter), 

Da die Absonderung der Driisen nicht als einfache Piltrati 
Polge der verinderten Blutfiille angeschen werden darf, sondern dof 
stindige Leistung der secernierenden Zellen neben der Veriinderang an 
anftritt, geht aus folgenden Tatsachen hervor: 

1. Die absondernde Tatigkeit der Drive bei Reixung der Nerven biilt s 
lang an, nachdem alle Gefibe unterbunden sind (Crermak™, Gianuesi® 

2. Atropin und Daturin vernichten die Titigkeit der Sekre 
in der Chorda tympani, nicht jedoch die der gefiberweiternden Fas 
hain), — Durch Yohimbin kann der BlutdarchiiaB durch die Driise 
10fache gesteigert werden, e da® Speichelsekretion ointritt, ¢ 
verbrauch der Driise bleibt dabei unveriindert. Wird aber nachher die Choré 
tritt Speichelsekretion ond damit eine Steigerung des Sauerstoffyerbranchs 
Fiache ein (Barcroft uv. Miller), 

3. Der Druck im Ansfihrungsgange der Speicheldriisen (dureh ein 
‘Manometer 2u messen) kann fast die doppelte Hihe betragen als der in « 
Geffen der Driise (C. Ludwig), im Ausfihrangygange der Submaxillaris 
200mm Hg. — [Mit Steigerung des Druckes im Ansfilirangsgange nimmt 
menge ub, ebenso auch die yon der Driise geleistete Arbeit (Granbaum™)), 

4. Abnlich wie Nerv und Muskel ermfiden auch die Speicheldrisen, a 
Finspriteung von Siluren oder Alkalien in den Ausfihrangsgang, Es bewelst | 
sekeotorische Gewebe unabhiingig von der Circulation unter dem influ der 
(Gianuzzi"). 5 

Es muB somit gefolgert werden, da ein direkter EinflnB 
auf dio Sckrotionszellen der Driigen vorhanden ist, unabhingi 
Vermittiung durch die Gefibe, 

Wahrend der Sckretion steigt die Temperatur der Submaxillariy 
der Chorda um 15° (Ludwig u. Spiess*), bei Reizung des Sympathikus 
(Burton-Opitz®), die Drige sowie das aus der Vene abtiiellende Blut i 
wirmer als das Arterienblut. 











(81004) BA NSchatten und Zusammonsetenng dos Speichels. 


Das Reflexc"t'um steht in leitender Verbindung mit den Ga 
halbkugeln, WS schon daraus hervorgeht, daf bei Vors 
sebmeckender SubS!anzen zumal im Hungerzustande diinnfllissige $ 
eintritt (vgl. Paclow*). Auch bewirkt Reizung der Gro®hirnr 
der Gegend des Sulcus cruciatus Speichelflus beim Hunde (Lépine* 
de Bary** erbielt Speichelsekretion beim Hunde nach Reizung ein 
im Gyrus suprasylvius anter.; Kerber3* zeigte, dai beim neug 
Hunde dieses Centrum noch nicht funktioniert, obwohl Reizung de 
Speichelsekretion bewirkt. 

Solange jede Nervenreizung unterbleibt, findet anc 
Speichelabsonderung statt, wie im Schlafe (Mitscherlich*). 
sistiert unmittelbar nach Durebschneidung aller Driisennerven 8 
Absonderung. 

Nach Pawlow u. Glinshi® reagicren die verschiedenen Speicheldrasen 
auf den Reiz der eingefubrten Nahrung. Wiibrend die Submaxillaris (beim Hund 
alle Reize, welche die Mundschleimhaut treffen (Fleisch, aber auch Sand, Sli 
Speiehel absondert, tritt hei der Parotis, wenn dem Hunde rohes Fleisch oder fe1 
zu fressen gegeben wird, keine Sckretion ein, wohl aber, wenn ihm fein gepn 
trocknetes Fleisch oder trockenes Brot gegeben wird (vgl. Popieleki). — Cher div 
Yer Parotis beim Pferde vgl. Scheunert u. Gottschalk *, beim Menschen gl. ¢. Zt 
Brunacei. 

Die Parotis des Schates (Wiederkiiner) secerniert kontinuierlich (Kekhard’ 
schneidung aller gutretenden Nerven dindert hierin niehts. Vielleicht enthalt deat 
die Anregung der Absonderung leitendes Centrum in sich selbst, 

Fntzindungen der Mundhdhle, Neuralgien der Nerven derselben, Durel 
2Zihne, Geschwire der Sebleimbant, Auflockerungen des Zahnileiaches (x. B, nach a) 
Quecksilbergebranch) rufen oft Iebhafte Speichelabsonderang (SpeiebelfloB, Ptyalism 

Auf die Speichelsekretion wirken dicjenigen Gifte, welche tberhaupt m 
innervierte Organe wirken (§ 270), niimlich Atropin lihmend, Pilocarpin 
stigmin, Masearin anregend auf die porasympathischen Fasern, d.h. die 
Sekretionsfisern. Der durch Pilocarpin bewirkte Speicheliiu wird dare Atropin a 
nimgekehrt wirkt bei der Sistierung der Speichelsekretion durch Atropin die Ver 
von Piloearpin, Phy#ostigmin oder Musearin wieder speicheltreibend, — Cui 
speleheltreibend durch Reizung des Centrums (Heck), 

Pawlow®® ywigte, dab ex gelingt, auch solche iufere Kinwirkungen mit 
Jorisehen Speichelabsondernng in Verbindung zn setzen, die xunfichst in keiner ? 
damit steben. Wenn man einem Hunde Speisen in den Mund bringt, die Speichela 
hewirken, xugleich damit aber regelmabig eine andere Eeregung centripetaler Ne 
tie an sich zuniichst keine Speichelsekretion bewirkt, #. B. der Anblick der Sp 
auch hestimmte Gerausche, Kratzen einer bestimmten Huntstellc usw, #0 erfolyt n 
Yoit Speiehelsekrotion auch dann, wenn keine Speisen in den Mund gebracht, 
die damit bisher regelmaBig yerbundenen Exregungen gesetat werden; Speich 
orfolgt also x. B. schon beim Anblick der Speise, oder beim Ertonen doa Gere 
beim Kratzen der hestimmten Houtstelle (.Bedingte Reflexes) 

















100. Eigenschaften und Zusammensetzung des Spei 


Methode. — Zur fangeren Beobachtung der Speichelsekretion unter da 
malen Verhiltnissen hat Glinski Wei Hunden den Teil der Schleimbant, in w 
Ausfihrungsging der betreffenden Drise sich éffnet, mit einem Kleinen Stick dt 
ganges frei priparicrt, durch eine spaltfirmige Offnung der Mandhiilenwand 
gezogen und hier «i it. Der ausiliefende Speichel wird durch einen Tricht 
Gliisehon aufgefangen. 


Die ,Mundflfssigkeit* ist ein Gemisch dey Sekrete der 
driisen und der kleinen Driisen des Mundes, 


1. Physikalische Eigenschaften. — Opaleszierend®s Se 


geruchlose, etwas fadenzichende Fltissigkeit von Loge 


Gewicht und alkalischer Reaktion gegen Lacy 











[etn *“yslologische Wirkungen des Speichels. 


Gase des SPCHMELs, — tm Submaxillasisspeichel fand Pfliger® in 100 
— 64,7 00, (tells “P"Mphare, tells durch Phosphorsinro austreibbare); — 
Kaiz™ tad im Parctidenspeichel des Menschen bis 146 Vol-Prozent 0, — 3,2 
auspumpbare CO, und "2 gebundene CO,. 

Abnorme Speichelbestandteile, — Vermehrten Harnstotf fund man be 
(Pleiacher™), Harnsiure bel Uriunie (Boucheron), berhaupt stets, wonn die Ha 
Tiate vermebrt ist (Stocker®). Von verabreichten fremden Substanzer 
den Speichel Uber: Quecksilber, Kalinm, Jod+ und Brommetalle, Blei, Morphin, Lith 
sale (Ellenberger*). 


Der Speichel der einzelnen Speicheldriisen. — Der Speichel der Pa 
hilt kein Mucin, ist daber nicht fulenzichend, leicht nd; alkaliseh (gegen 
you 1,003—1,006 spez. Gew. Der Speichel der Submaxillaris enthilt stets N 
ist daher etwas fudenziehend; der der Sublingnualis ist sehr reich an Mucin 
stark klebrig, Der Speichel dieser beiden Drasen reagiert stark alkalisch geger 


101. Physiologische Wirkungen des Speichels. 


I. Der Speichel enthilt als physiologisch wichtigsten Bestan 
Ptyalin, ein hydrolytisches Ferment, welches die Verdanung dei 
hydrate einleitet. Es verwandelt die Polysaccharide unserer 
yon der Formel (C,H,)0;)x, im wesentlichen Stuirke, Amyl 
infolge ihres groben Molekiils schwer léslich und daher nicht zm 
tion geeignet sind, unter Wasseraufnahme in Kérper von kleinerem 
die nanmehr leicht lislich sind. Als Zwischenprodukte entstehi 
auniichst Dextrine, Kérper, die auch noch 2u den Polysacchariden 
aber schon ein wesentlich kleineres Molektil als die Stirke hal 
Endprodukt ist cin Disaccharid: Maltose C,H. 0,, (vgl. § 7) 

Wenn man durch Kochen mit Wasser verkleisterte St 
Speichel versetzt und bei Kérpertemperatur stehen list, so kann 
Verlauf der Umwandlung im einzelnen yerfolgen, Zuerst entsteht u 
fliissigang des Stirkekleisters das Amylodextrin: es reduziert 
sche Lisung nicht, firbt sich durch Jod blau (ist Hauptbestandteil 
.lisliche Stiirke* oder Amydulin bezeichneten Priiparates). Die 
fibergeflihrt in Erythrodextrin, Feidingsche Lisung sehwach red 
dureh Jod sich rot fuirbend. Dieses wird in Achroodextrin tibe 
Fehlingsche Lisung reduzierend, durch Jod unfiirbbar, Aus diesem 
schlieBlich Maltose (und Isomaltose?), 

In keimonden Getreidekirnern kommt ein ahnlich wirkendes Ferment vor, die 
sie verwandelt die in den Samen als Reservematerial aufgespeicherte Starke ¢ 
Maltose und macht sie so der keimenden Pilanze xuginglich (ygl. die Herstellung de 
bei der Bier! wr durch Keimenlassen von Gerste). Danach heien alle Fer! 
Vulysaccharide in Disaccharide umzuwandeln yermigen, dinstatische Ferme: 

Dureh Kochen mit verdiinnter Schwefel- oder Salzstiare 
Stiirke ebenfalls gespalten; doch macht die Zersetzung nicht bei 
dung von Maltose Halt, sondern diese wird weiter gespalten un 
ganze Stlirke in Dextrose thergefihrt. Im Gegensatz hierau wi 
das Ptyalin (und die diastatischen Fermente tiberhaupt) die Stu 
fiherwiegenden Teile nur in Maltose tibergefiihrt; daneben wird i 
eine allerdings nur geringe Menge von Dextrose gebildet (Kalz u 
Hamburger™). 

Darstellung des Ptyalins. — 1. Man erzengt in dem Speiehol durch 
Phosphorsiture und Kalkwasser einen voluminésen Niederachlag von Calciumphy 
this Ptyalin mit niederreift, Dieser Niederschlng wird auf dem Pilter gesammelt 
mit wenig Wasser das Ptyalin daravs anfgelist. In diesem wigeerigen Auszug 














(#102) Die Kanbowagung. 


102. Die Kaubewegung (Masticatio). 


Das Kistergelenk ist durch einen Zwischenknorpel (Vidias > 1567), 
bel der enetgischen Witktng der Kaumuskeln den gegenseitigen direkten Drack der) 
fiehen abhalt, — in Zwei fibereinander lingende Hoblriume geteilt. Die Gelenk 
namentlich durch das linfere Band anschnlich verstirkt, ist so gerinmig, daB sic 
dem Heben und Senken des Unterkiefers zugleich noch eine Verschiebung des | 
Kopfes nach worn anf das Tuberculum articulure 2uligt. 

a) Die Erhebung des Kiefers — wird durch die vereinigte 
‘Kung der Musculi temporales, masseteres und pterygoidei interni be 
War vorher der Unterkiefer stark gesenkt, so daf die Gelenkkipfe 
vorn auf die Tuberenla articularia getreten waren, so gehen sie nw 
in die Gelenkhihle zuriick. 

Bei Erhebung des miglichst hervorgestreckten Unterkiefers fallt die W 
der Mu. temporales ans, weil diese bei ihrer Hobowirkung den Kiefer zugleich xurie 

; — bei moglichst stark zurfickgeschobenem Unterkiefer wirken hebr 
die Temporales, weil die anderen Muskeln zugleich hervorzichend wirken wirden; 
seitlich verschoben gehaltenem Unterkiefer fillt die hebende Wirkung der 
rales ans. 

b) Die Abwirtsbewegung des Unterkiefers — erfolgt schon 
sein Gewicht, — unterstiitzt wird sie durch miifige Contraction det 
deren Biuche der Digastrici und der Mm. mylo- und geniohyoidei. 
Muskeln wirken stirker bei weiterem und angestrengtem ()ffner 
Mundes. Die hierbei notwendige Fixierung des Zungenbeines besorge 
Omo- und Sternohyoidei sowie die vereinigt wirkenden Sternothyr 
und Thyreohyoidei. 

Da beim starken Niedergehen des Untorkiefers sich die Gelenkkipfe nach vt 
die Toberenla articularin begehen (Ravine 1719), so ist angonommen worden, cd 





in 





Fualle die Mm. pterygoidei externi dieses Vorschicben aktiy beginstigen. —- Bei be 
starker Mundoffnung wird der Kopf hintentber gebengt, wobei (bei tixiertem Zang 
die hinteren Binche der Digustrici sowie die Stylohyoidei wirken. — (Bei m 





Pieren sind anf- und abwiirts bewegliche Oberkiefer vorhanden, x. B, bei Pap 
Krokodilen, Schlangen und Fischen.) 

ce) Verschiebung beider oder eines Gelenkkopfes nach 
oder hinten. — 1, Das Hervorstrecken des Unterkiefers bewirke 
Mm. pterygoidei externi. Da hierbei der Gelenkkopf auf das Tuber 
articulare (also auch niederwirts) tritt, so mitissen die Fliichen der seit 
Zihne in dieser Stellung von einander weichen. — 2, Die zuriickzie 
Bewegung besorgen die Mm, pterygoidei interni, — 3, Es wird nu 
eine Gelenkkopf nach yorn gezogen und wieder zurtick durch di 
pterygoideus externas und internus derselben Seite; hierbei findet 
Transyersalbewegung des Unterkiefers statt. — Je mehr der Unter 
gesenkt ist, um so unergiebiger sind diese Bewegungen. 

Bei der Kaubewegung, bei weleher sowohl die Hebung und Ser 
des Unterkiefers als auch die transversale ,Mahlbewegung* sich 
fach kombinieren, werden die zu zerkleinernden Speisen von auber 
durch die Lippenmuskeln (Orbicularis oris) und die Buccinatoren, — 
innen darch die Zunge unter die Kauflichen der Backen- und Mabl 
geschoben. Das Muskelgefithl der Kaumuskeln sowie das Tastgefiih 
Zibne, der Mundschleimbhaut und der Lippen regulieren auf reflek 
schem Wege die aufzubictende Kraft der Kiefermuskeln: das Re 
centrum fiir die Kaubewegung liegt in der Medulla oblongata 
$278. 5). Unter gleichzeitiger Finspeichelung kleben die zerteilter 
tikel zn einer Masse zusammen, Welehe dann auf dem Zungenriickey 
linglichrunden =Bissen* (Bolus) geformt wird, 





[103] Ban und Entwicklung der Zihne. 
‘etas wand verkalkte Oy li 
‘See recilagete = beraiene. Tie ogee Atel Lon: Gee Sabieapltel Die 
Mautehen. 


‘Das Cement — (Substantia stellt cine dinne, Warzel i) 
Kaochenrinde dar (Fig. 68a). mane “ ae 


Chemie der Hartgebilde des Zahnes. — Die Zihne bestehen ans cin 
leimgebender Substanz, durchdrangen von Caleiumphosphatcarbonat (ital) 
Knoeben). — 1, Das Dentin Re eos Substanz 27/ nat 

72,06, — Magnesium) a » neben Spuren Eisen, an 
siure (Aeby™, Hoppe-Seyler’ ers Mattes, 00, (Gabried™, ay 


ig. 87, sitet als organis« 


organi 
stanz): — Oaleiu 


stimmt vollig 4 
Knochensubstans, 


Weichteil 
ness — Die 
— ist im erwael 
der Rest der Zahi 
A Zahoschlitf an der Grenze b ewitchon Dontis und Schmele, welche sich die 
je Sehmele — Dentinsehicht abg) 

Sie besteht aus 

unter weniger 
tigen, eapillurreichen Bindegewebe mit Bindegewebszellen und Leukocyten. Di 
lichste, dem Dentin aniiegende Schicht der Zellen sind die Odontoblasten, d. bh. 

Yellen, von welchen die Bildung 

aa ausgeht. Sie entienden in die 

lange Fortsitee, wihrend ihe keenb 
kirper, auf der Oberitiiehe der Pull 
durch andere Fortsitze eine Verbindy 
Pulpa und mit benachbarten Odonto 
wirkt, Zablreiche markhaltige, nach ¥ 
feilung marklos werdende Nervenfal 
gen awischen die Odontoblasten 1 
unter dem Zahnbeine mit freien, hi 
knotig verdickten Spitzen. Weitere F; 





@ Schnielx, ¢ Dentineheen. — 8 stark ¥ 
prismen, — C dieselbon im Qoereehtitt, 




















gen unter pinselformiger Ansstrahluny 
faseriger Plexus liegt nnter dem 
Die Arterien des Zahnes liegen of 


M14 Yi, der Nervenstimmehen; die Capill: 


dor Wareal; « Comont mit Knoehen> welbet \bis:hn dhe” Cdontebiestealaqesro 


> Dentin mit Zahnkanilohen, Die Entwicklung der Zithn 

Aes: schon gegen den 40. Tag, Aut der 

des Kieferrandes betindet sich eine 

Rpithelialschichinng gebildete, hervorragende Kante, der Kieferwall*. Von| 

thelsebicht senkt sich in den Kiefer hinein eine ebenfalls on Fpithelien ange} 
sie Zahnfurche*. Die Zahnfurche vertieft sich weiterhin in ihrer 

ting zn einer Form, welche dem Querschnitte einer yon wnten eingebuch' 





(sj Seblingbewerung. 


angeprebt, wodurch der Mundinbalt nach dem Rachen hin verdriin 
Ist ier Bissen an den vorderen Gaumenbiigen v igeglitten (der 
der Mandeldritsen macht ihn schlipfrig), so wird ihm die Riick 
die Mundhihle dadureh abgeschnitten, dal die in den yorderen ( 
bigen liegenden Mm. palatoglossi diese Bigen kulissenartig strafi 
einander und gegen den erhobenen Zungenriicken (M. stylogloss 
spannen, 

Der Bissen betindet sich nonmehr hinter den yorderen ¢ 
bigen und der Zungenwurzel, im Innern des Schlundkopfes der suk 
Kinwirkung der drei Schlundschniirer ausgesetzt, welche ihn» 
herschieben. Dabei muf — 1. das Cavum pharyngo-nasaleabg: 
werden, damit der Bissen nicht in die Nasenhohle getrieben wi 
— 2. der Eingang zum Kehlkopf geschlossen werden, um ci 
schlucken* zu verhtiten, 

Der AbschluG des Cavum pharyngo-nasale erfolgt in de 
daG sich die Tiitigkeit des oberen Schlundschniirers stets kombin 
einer horizontalen Erhebung (M. levator veli palatini; N. facialis ode 
und Anspannung (M. tensor veli palatini; N. trigeminus, Ggl. otic 
weichen Gaumens. Der obere Schlundschniirer prebit (durch den M. 
pharyngeus) die hintere und seitliche Pharynxwand wulstférm 
gegen den hinteren Rand des horizontal erhobenen und gespannten ( 
segels (,,Passavantscher Wulst*), wobei sich zugleich die Rin 
hinteren Gaumenbigen nithern (M. palato-pharyngeus). 

Bei Menschen mit angeborenen oder erworbenen Defekten des weichen 
gelangen beim Schlingen Speiseteile in die Nase. 

Der Kehlkopfschla6 kommt in folgender Weise zustande 
wird der Kehlkopf (bei Fixation des Unterkiefers) in der Richtu; 
oben und vorn unter die hierdurch sich tiber ihn hinwegwilbende | 
wurzel emporgezogen. Dies geschieht durch Emporhebung des Zungi 
nach yorn und oben durch den M. geniohyoidens, den yorderer 
des Digastricus und den M. mylohyoideus sowie durch Anniihert 
Kehikopfes an das Zangenbein durch den M. thyreohyoidens. — b 

mun noch die Zunge durch die Styloglossi etwas nach hinten 
wird, driickt sie den Kehldeckel iiher den Kehlkopfeingang nie 
Aa6 der Bissen tiber ihn hinweggleiten kann. — c) Es wird fiber 
Kehldeckel durch die Muskelfasern des Reflector epiglottidis und ¢ 
© piglotticus tiber den Kehlkopfeingang niedergezogen. — d) Endl 
Brindert die Schliehung der Stimmritze durch die Constricto 
BXehlkopfes ein Eindringen der niedergeschluckten Substanzen 
Euarynx. 

Absichtliche Verletzangen des Kehldeckels bei Vieren oder Zerstirung dest 
Menschen sichen leicht -Verschincken* von Filissigkeiten nach sieh, wiht 
Wissen xiemlich obne Storangen niedergebracht werden konnen. Bei Hunden wer 
<Aings gefirbte Flissigkeiten vom Ricken der Zungenwurzel direkt in den Schium 
Wefinlert, obne dab sie die obere Fliiche des unter der Hberhingenden Zungenw) 
Woorgenen Kehldeckels zn fiirben branchen. 

Wenn so der Bissen an dem Nasenrachenraum und am K 
eingang vorbei passiert ist, gelangt er in die Gegend der mittle 
unteren Schlundsehniirer, durch deren Contraction er in den Oeso 

trieben wird. In der Speiserihre, deren geschichtetes Plattenepith 
len Schleim kleiner Schleimdrtisen schlipfrig erhalten wird, erfol 
die Abwirtsbewegnng durch eine peristaltische Contraction der 





18105.) Bewegungen des Magens. 


jedoch nur fur den ia S**il der Speiserihre; im Brusttell ist die Speiwernuin 
Fremdkérper direkt re#*ar, os wird hier eine peristaltisebe ae 
Fremakirper in den Men befordest. Diese Reizbarkeit nimmt mit der 
Pharynx an. Die Peristaltik setzt sich stets ber die ganze Linge der Spoisero 
‘sogar wenn dieselbe unterbunden jst, oder ein Teil derselben ausgeschnitten war 
Rbengo verliiuft die Peristaltik bis abwiirts, wenn man Hunde ein an einem Fader 
Fleisch bis zor halben Oegophagusliinge versehlucken lift und es yon 
herauszieht (C. Ludwig u. Wild“), 
Nach Kronecker u. Mettzer*™ ist dic Dauner deg Schlingens — 
0,3 Sek.; dann contrahieren sich die Sehlundsebniirer, 0,9 Sek. gspiter der ob 
‘bnitt, sodann nach 1,8Sek. der mittlero und dann nach 3 Sek, 
ie Verengerung der Kardia, nach dem Durchtritt der Massen, macht den Bi 
gesamten Bewogungerethe, — Nach Schreiber’ beginnt otwa 0,2 Sek. nach 
Mundschinckens (Mylohyoideus-Wirkung) guerst eine Eroffnung des Ocsophagn 
un die Pharyoxsehndrer wirken. Daran schlieBt sich die peristaltische Wi 
Maskulatur der Speiserviire, welche bis xum Eintritt in den Brostkorb 3,5 Se 
zur Karilia 5—7 Sek. dauern kann (vgl. Kraus), 


105. Bewegungen des Magens'", Das Erbrechei 


Methode. Zur Untersuchung der Magenbewegungen dient: 

a) ein durch eine iinfere Magentistel bei Tieren eingebrachter Gummi 
man an versehiedene Stellen dex Innenraumes bringen kann; der Ballon ist 
Sehreibyorrichtung durch Luftibertragung (§ 51. 2) verbunden (Ducceschi*®), 

b) Die Beobachtung des Anstritts des Mageninhalts aus Dnode: 
(Birsch!, ©, Mering', Morit="*, Otto, Tobler™), 

¢) Die Bestimmung des im Magen herrachenden Drucks and der Ande: 
selben miltetst der Schinndsonde (Moritz"*), 

d) Die Durchleuchtung mit Rintgenstrahlen; dabei wird der Magen 
Speisen angefllllt, die mit dem fir Rontgenatrahlen undurchlissigen Bismutum | 
versotzt sind (our u. Balthasard™", Cannon"), 

Der heransgenommene, in einer fouehten Kammer legende Magen zeigt 
gungen (Hofmeister u. Schatz"). 

Am Magen verlaufen inBere longitudinale, innere ringfirmige Fus 
innorst in diagonaler Richtnng die Fibrae obliquac, jedoch mit vielfachen 
ineinander, Am Pylorns hildet die Muskulatar einen ringformigen Se blic 
(Sphinctor pylori), dessen Fasern sich bis in die Valynla pylori hinein erstreckes 

Kardia grappieros Fasern xn cinem .Kardiaschnirer. 

Bei den Bewegungen des Magens sind getrennt 2a be 
1. Die Bewegungen der Kardia. — 2. Die Bewegungen der Magi 
— 3. Die Bewegungen des Pylorus. 

1. Die Bewegungen der Kardia. — Bei gefiilltem Ma 
normalem Salzsiiuregehalt des Mageninhalts (Cannon'*) ist diy 
durch die in ihrer Wand gelegenen Muskeln (Strecker™®) geschk 
da® der Mageninhalt selbst bei Drucksteigerang im Magen nich) 
Oesophagus gelangt. Eréffnet wird die Kardia reflektorisch bei se} 
Reizung der unteren Oesophagusschleimhaut, wie sic d 
niedergleitenden Bissen ausgelist wird; auf diese Weise eréffnet d 
selbst sich den Weg zum Magen. Auf starke Reize hingegen ver 
sich die Kardia; so werden kaltes oder kohlensturehaltiges 
iitzende Flissigkeiten vor der Kardia angehalten (Kronecker u. ¥ 
Cannon u. Moser, v. Mikulicz"°, Kraus**), 

Bei schnell aufeinander folgenden kleinen Schlucken wird die Kardia erst 
dritten bis vierten Schinck gedffnet (Kronecker u. Meltzer), 

Beim Verschlucken fitzender Flissigkeiten tindet sich die Veriiteang » 
gerade im unteren Teile des Ocsophagus, weil die itzende Filissigkcit yor 
angebalten worden ist. 

2. Die Bewegungen der Magenwand. — Der Fundus- 


Torusteil des Magons verhalten sich in ihren Bewegungen durcl 











Cannon) und Mt Pett (Best u. Cohnheim') bewirken £ 
Pylorus; d: in bewirkt Berithrung der Duodenalschleimhaut 11 
alkalischen Plussigkeiten, Salziisungen Entleerung des Magens ii 
denum, In abnlicher Weise wird aber Schlué und Offnung d: 
auch yon der Magenschleimhaut ans reflektorisch beeinfli 
Cannon * bewirkt Berlihrung des Pylorusteils des Magens mil 
Speisebrei Erschlaffung des Pylorus. 
Der Pylorusreflex hat zur Folge, daf die Entleerung de 
in den Darm in einzelnen Sehiiben erfolgt, Ist der / 
des Duodenums leer, eventuell sogar mit alkalischem Darmsafte | 
so ffnet sich der Pylorus, sobald der saure Speisebrei die 5 
des Pylorusteils des Magens beriihrt, ein Teil des Mageninhalts t 
Dnodenum ein. Durch die Bertlhrnng der Darmschleimhant mit d 
Mageninhalte wird aber sofort wieder Schlui des Pylorus bewir 
vergeht jetzt eine gewisse Zeit, bis der Inhalt des Duodenums n 
resp. weitergefiihrt ist: alsdann erfolgt wiederum (ffnung des Py 
Eintritt eines weiteren Teiles des Mageninhalts in den Darm. 
Nach Boldyre™ soll unter bestimmten Bedingungen (bei fettreicher | 
reichlicher Siuremengen in den Magen, wihrend des Hiingers) ach « 
treten yon Pankreas-, Darmsaft und Galle aus dem Duodenam in den Magen 
Im Magen sollen dann unter dem Fintlu® vor allem der Pankreasfermente ¢ 
Verdanangsvorgiings sich vollziehen; besonders soll die Fettverdanung im Mage 
tunler dem FiniluS zuriickgetretenen Pankreassaftes erfolen. 

Tnneryation der Magenbewegungen. — Das Centrur 
Magenbewegungen liegt im Magen selbst in Gestalt des auton 
Gangliennetzes des Plexus Auerbachii awischen den beiden 
der Muscularis (vgl. 5.244). Die Kardia und der Pylorus haben 
automatische Ganglienzellen (v. Openchowski*). Diese automatise 
rate stehen mit dem Centralnervensysteme in Verbindung durch d 
und den Sympathicus. 

Nach e. Openchowsk 
in den hinteren Vierhigeln, v 
die Splanchniel, abwiirts laufon. 








liegt ein Centrum fiir die Contraction ¢ 
wo aus dic Bahnen meist durch die Vagi, w 
Das Centrum fir die Eréffnung der Ka 
Corpus striatum (und in Verhindung damit cins am Suleus cruciatus der E 
Hundes); dic Ieitende Bahn geben die Vagi ab. Auch im oberen Rickenmar! 
Sffnende Contra, yon hier Minft die Bahn darch den Symphathicus (Plexus aorth 
niens minor). Retlektorisch liGt sich eine Eriffnung der Kardia bewirken d 
der sensiblen Eingeweidenerven (auch des Ischiadicus), 

Fir den Magenkorper liegt ein Contractionscentrum in den Vir 
wo Buhnen durch die Vagi und das Riickenmark und yon leteterem in den 
treten. Hommende Contra enthilt das obere Rickenmark; die Bahnen geb 
Sympathici und Splanchnici. 

Der Pylorus zeigt einen gowissen, jedoch wechselnden Tonus im Ver 
Splanchnicas kann den Pylorus mehr eroffnen, der Vagus ihn versehlieben. Ds 
fir die Bréffnung der Kardia hemmt die Pylorushewegung: Babn durch 
mark und dje Splanchnicl, Hemmende Pyloruscentra liegen in den Vi 
den Oliven: Bahn durch das Rickenmark. Das Kardia-eroffuende Hirnrinde: 
trahiert zugleich den Pylorus: Bahn durch die Vagi. Contractionscentri 
Hegen in den Vierhtgeln: Bahn durch die Vagi (wenige Fasern durch das 
und den Sympathicus). 

Der heransgenommene, in ¢iner feuchten Kammer oder in Kinger 
Hegende Magen zeigt noch die Peristaltik des Antrum pylori; dagegen nicht 
SohlicGung des Pylorus (Cohnheim™*), Darchsehneidang der Vagi oberhalb ¢ 
TaBt den ‘Tonus, dio Bewegungen des Magens und Pylorus unverindert 
o. Mering “), cbenso Ansrottung des Plexus cocliacus (nach zuerst auftretends 
Durehschneidung der helden Vagi am Halse dagegen bewirkt sokretori#ele 
Stimngen des Magens (Katschkowsky '). 


Landols: Rosomany, possioim Av 








106. DarmbeWegungen. Innervation der Darm 


Methode. — Zur Reobachtmg der Darmbewegungen 
hohie zur Vermeidung des Tauftentritien unter blutwarmer mah tees Kod 
(eum Braan-Houekgeest™), — oder man beobaehtet durch die rasii 
Banebdecken hindureh (Pal'*). Katseh u. Borchers" lieben ein Zell 

eines Kaninchene einhellen und beobaehteten dareh dies 
des Magens und Darms. — Cannon'* untersuchte die Darmbewegun 
straklen, der Darminhalt wurde durch Bismutum subniteieum ftir die R 
darehsichtig gemacht (vgl. $289). —- Man kann anch den Darny ang d 
nehmen und in sanerstoffgeslittigter Ringerscher Lisung von Korpert 
‘wegungen beobachten (Magnus). 

Am Darm kommen zwei Arten von Bewegungen yor: | 
Pendelbewegungen und die peristaltischen Bewegun 

Die Pendelbewegungen oder Mischbewegung 
segmentations*, Cannon’) bestehen in einem rhythmisi 
Herbewegen des Darminhalts in einer Darmschlinge ohne We 
desselben. Sie bewirken dadurch eine sehr innige Vermisch 
inhalts und bringen ihn immer aufs neue mit anderen Stell 
haut in Beriihrung. 

Die Pendelbewegungen sind in ihrem Rhythmus und threr Geschy 
Temperatar abhingiz; bei Korpertemperatur erfolgen 10—12 Pendet 
Minute, jede in einer Daner yon 5—6 Sekunden (Magnus™®), 

Die peristaltischen Bewegungen treten auf, + 
(ota lee mechaniseher Art durch Berithrung der Da 

loch sind auch mechanische, chemische, elektrische Reizun 

fliche des Darms wirksam) den Darm trifft, Es kommt da 
Reiz aus magenwiirts gelegenen Teilen des Darms zu ein 
in den afterwirts gelegenen dagegen zu einer Erseblaffi 
Starling’): auf diese Weise wird der Darminhalt verseh 
nun yon einer weiter unten gelegenen Stelle denselben — 
auslisen. 

Pendelbewegungen und Peristaltik kommen am Di 
darm vor. Am Cécum und obersten Teil des Kolons gese 
normalen Peristaltik noch eine Antiperistaltik, die den 
nicht weiter vorriicken la6t, sondern immer wieder zurlick! 
Anfang des Dickdarms zu erneuter Darcharbeitang (Cannon! 
gewissen Zeit wird dann die Antiperistaltik durch eine in 
tung verlaufende peristaltische Welle abgelist, die den Inh 
befirdert. 

Die zwischen Diinn- und Dickdarm gelegene Valvuli 
der die Diinndarmmiindang ringfirmig umgebende Sphin 
sehliefen unter normalen Verhiiltnissen den Dieckdarm 
yollstindig ab (vgl. Hertz '®*), so dab einmal in das Kolon ¢ 
nicht wieder in den Diinndarm zurtickgelangen kénnen. U 
Verhiiltnissen kann aber gleichwohl die Valvula Bauhini a 
werden (s. unten). 

Der Sphincter ileo-coliens wird nach Elliott ™® vom Splanchniew 
Durchschneidung des Splanchnicus oder Zerstornng des Rilekenmarka wi 
Vihmt, so da6 Dinn- und Dickdarm mit einander kommounizieren; eine 
gung der Verdanung scheint dadurch nicht hervorgerafen 21 werden. 

DaG sine Antiperistaltik im ganzen Darme vorkomimen kann, 
ans dem Anftroten des Koterbrechens bei Menschen mit Darmyerschlo 
Kotige Gernch der orbrochonen Magsey kann jedoch auch herrihren vo 
Verweilen der Massen im Doodenym, yon wo aus, wie das allbekannte 
zeigt, Ingesta in den Magen 2urjojtyeten kommen. Versuche, in denon 





($106) Innervation der Darmbewegungen. 


sich Mannose, 104 Galaktose in hiherer Concentration, dagegen ist Frakta 
sie wird auch nicht ¥on dem Darm yerbraucht. Disaceharile sind ebenfalls w 
anch eine groBe Reih® underer organischor Stofte. Bemerkenswert in, da de 
siure chenfalls eine Stirk anregonde Wirkung besitst (Neubireh u. 18), 
dentung des osmotischen Drocks der Nihriliissigkeit fir die Darmbewegungen 
— Zuelzer, Marzer 0. Dohrn extrabierten aus der Magenschleimhant anf 
Verdannng, aber anch aus Milz einen Stoft, der die Poristaltik bei Injoktio, 
stark erregt: Peristaltikhormon, Hormonal (vgl. Dittler u. Mohr'™ 
gewann darch Extraktion mit Tyrodescher Lisung oder destilliertem Wasst 
Dinn- oer Dickdarm eine Sabstanz, welche auf den Gberlebenden Darm stark « 

Der Plexus submucosus (Meissner) enthalt cin Reflexcentram 
eularig mucoswe: bei Berdhrung der Darmschleimhant mit einem spitze 
{Knochensplitter, Nadel) weicht die berthrte Stelle zarick, die benachbarte 
sich: so witd der Gegeostand an seinem spitzen Endo fostgehalten und durch 
welterbin mit dem andern, stumpfen Ende nach vorn forthowegt (ener *), 


Die peripheren Darmneryen. 


Anatomisches. Dio peripheron Darmnerven stammen aus dem anto 
system (vgl. $270), ond 2war verlimft vom Sympathicus im engeren Sinne de: 
nicns major und minor, vom parasympathischen bulbiren System der } 
Darm. Der N.splanchnicns major stammt aus den Rami communicant 
der N.splanchniens minor aus denen des 10.—12. Dorsalneryen; die Fa 
als priganglionire Fasern ohne Unterbrechung dureh den Grenzstrang de 
und enden erst an den Ganglienzellen des Gangl. coeliaenm nnd Gangl. maser 
‘Teil an noch weiter peripherwiirts gelegenen Ganglienzellen. Von hier aus verl 
postganglioniiren Fasern als Nn, mesenteric! zam Darm, Die in den Verlar 
Tasern eingeschaltoten Ganglienzollen legen durchweg in dea innorvierten G 

Der N. vagus vermehrt bei seiner Reizung die Bewe 
Verdauungstraktus, hauptsiichlich im Magen und oberen Teil 
darms, und zwar durch eine direkte Einwirkung auf den 
nur dadurch, dali er Contractionen des Magens hervorruft, welel 
als rein mechanische Impulse den Darm zur Bewegung anreii 
u. Starling “7, Klee'™). Ob die Vagi auch einige bewegungs! 
Fasern enthalten (Page May'**), ist zweifelhaft. 

Der N. splanchnicus ist: — 1. Hemmungsnery 
bewegungen (Pliiger*™, Klee?) Einige Autoren haben 
sonderen Versuchsbedingungen bei Reizung des Splanch) 
motorische Wirkungen beobachtet; nach Bayliss u, Starling’? 
sich dabei jedoch um Versuehsfehler: die Splanchnici sind 
reine Hemmungsnerven fiir beide Muskellagen des Darms. I 
bewirkt Reizang jedes sensiblen Nerven Hemmung der Darmt 
der Reflex verliinft dabei durch den Splanchnicus, da er 1 
seitiger Durchschneidung des Splanchnicus ausbleibt (Hotz '7*). 
N. splanchnicus ist auferdem der yasomotorische Nery ¢ 
arterien und Venen, mit Einschluf der Pfortader, beherrseht 
gribte Gefibgebiet des Korpers. Seine Reizung verengt, s¢ 
sehneidung erweitert alle muskelhaltigen Gefitbe des Darms. | 
Falle findet eine enorme Blutansammlung in denselben ste 
Aniimie der tibrigen Kérperteile eintritt, wodurch selbst der 
Blutleere der Medulla oblongata bewirkt werden kann. — 3. Der 
nicns ist endlich sensibler Nerv des Darmes (Neuwmann*"°; vy; 
Sensibilitiit der Bancheingeweide § 340). 

Roizung der Hirnrindo am Gyrns sigmoideus (Hund) sowie anSen n 
selben wirkt anf die Darmbowegungen durch die Vagi anregend, ebenso 
der Sebbigel. Hemmende Fasern verluifen von diesen beiden Stellen a 
Riekenmark, welches sig etwa yon der Mitte des Dorsalmarkes verlassen 

Mistnweski™), 


sw, “uuBETTIng des NOTE, 


gehen in den Mastdarm ereugt die Empfindung des Stubldr 
dem Stahldrange Nicht Folge geleistet, so kann das Geftih 
wieder eine Zeitlang verschwinden; es wird also nicht dure 
Handensein von Kotmassen im Rectum ansgeltist, sondern 
Chertritt des Kotes in das Rectam. Wenn nach einiger Zeit y 
tassen in das Rectum tibertreten, so stellt sich aufs Neue Stub 
Der Schluf des Rectums wird durch zwei Sphinctere 
Sphincter ani internus, der aus glatten Maskelfasern, und 
ani externus, der aus quergestreiften Fasern besteht. Bei 


Fige70, 





Der Damm and felow Muskeln. 

J Anuy, — 2 Steitboin, — # Sitzhocker, — 4 Lig. taberio-sactum, — 6 1atthoiapfat 

bulbo-cavernosnn, — Perino! superficialis, — F Fasoin des M. perine 

profandus, — JM. neh — OM, obturator internas, — 5 Mf. apbineter 
jevator ani, — 2? M. piriformis 





befinden sich in einer dauernden tonischen Contractio?s 
vermehrt oder gehemmt werden kann. Ein neryése* Gents 
die Bewegungen dieser Muskeln liegt in ihnen gerdeh vy 
Tonus derselben nach Zerstirung des Riickennar** et 
pathischen Ganglien nach anfinglichem Verschwinge™ aes 
(Goltz u. Ewald'*’, v. Frankl-Hochwart u, France” yn 
Normalerweise stehen jedoch die beiden Sphinetere™-s yo? 
tibergeordneten Centren im Riickenmark und igs a 
Das Centrum im Riickenmark (Budges a0) 
ist durch 2wei Bahnen des antonomen Systems 


verbunden (Hund, Katze, Kaninchen); Fasern, die, "7° 





(8107, Entlenrung des Kotes, Literatar (§ 97—107)- 


Bei Hunden, denen Lendois die hinteren Wareeln der unteren I. 
Sakralnerven simtlich durchschnitt, sah er, als sie sonst wieder horses 
After offen stehen; nicht selten ragte Mngere Zeit eine Kotmasse tr 
‘Da solchen Tieren die Sensibilivit im Rectum und After febite, so kont 
reflektorisch die Sphincteren zusammenziehen, noch auch erfolgte, durch 
nnlaft, cine willkiirliche Afterschliefang, welche doch sonst swelfellos » 
wikre (vel. Merzhacher*™). 

Sollen die Faces willktirlich entleert werden, so mub ¥ 
aus die Contraction der Sphincteren gehemmt werden. ' 
Innervation dieses Eipaumtnges pansies verliuft die Kotstiu 
After, ohne reflektorisch den Schluf desselben zu bewirken. 

Die die Defttkation einleitende stiirkere Peristaltik kann | 
im gewissen Grade erregt werden teils durch Pressen, teil 
kiirliche, kurze Bewegungen des Sphineter externus und des 
wodurch eine mechanische Anregung des Plexus myentericu: 
unteren Dickdarms bewirkt wird, welche nan den Dickdarm 7 

ristaltischer Bewegung veranlabt. Die Ausstofung der Kot 
rt durch die willkiirlich titige ,Banchpresse*, 2 
spiratorischem Zwerchfellstand. Die Weichteile des Beckengro 
bei starkem Stuhldrang konisch abwiirts gedriingt, wobei ¢ 
die zugleich venis-blutreicher werdende Afterschleimhaut hervo 
den Levator ani (Fig. 70 und 71) wird willkiirlich nunmet 
der Weichteile der Beckenhéhle gehoben und so der After im 
iiber die niedergehende Kotsiiule emporgestreift. Dadureh \ 
eine ausweitende Erschlaffung der Weichteile am Beckengrui 
lich der Fascia pelvis verhindert. 


Literatur (§ 97—107). 


1. KR. Heidenhain in L, Hormanns Handbuch der Physiologie. Loipzig 
2. EB Miller: A.m, A. 45, 1895, 463, A. A. 1896, 305. Zeitsehr. £. wise. Zoo 
624. — 3. J. N. Langley: J. 0, P. 2, 1879, 261. — 4. Zusammonfassende 
A. Noll: B.P. 4, 1905, 84. . Metzner in W.Nagols Handbuch d. Physiologie. Bro 
2, 899. — 6. P. Stohr: Festschrift £ Kolliker 1887. A.m. A. 47, 1896, 447. - 
Am A. 45, 1895, 93, 49, 1897, 707. 59, 1902, 407. — 7. C. Ludiig u. © 
N.F. 1, 1851, 255 u. 285. — 8. Eckhard: Boitr. x Anat. n, Physiol, Gielen, 
CL. Bernard: 0, 2.46, 1858, 159. 47, 1 
weroft: J.0.P. 25, 1900, 265 w. 479, 27, 16 
908, 731. — 11. L. Asher u. A.G. Barbera: %.B. 36, 1898, 154. — 12. 
PAA7, 1878, 1. — 13. JN. Langley uw. H. M. Fletcher: Phil. Transact. + 
of London 180 B, 1889, 109. — 14. L. Asher wu. W.D. Cutter: %. BAO, 
15. J. Czermak: 8. W.A. 39, 1860, 529. — 16. G. Gianuzsi: L. B. 1%, 
17. R. Heidenhain: P. A. 8, 1872, 309. — 18. J. Barcroft u, F. Milller: « 
250. — 19. C. Ludwig: %.r.M.N.F. 1, 1851, 271. — 20. 0. FF. Grinbe 
1898, 885. — 21. C. Ludwig u. A. Spiess: S. W.A. 25, 1857, 584. Ludwig: 
Nr. 28. — 22. BR. Burton-Opit: q 
4 physiol. 1, 1864, 507, — 24. angley: J.0. P. 6, 1885, 71. — 
A. J.P. 4, 1901, 483. — 26. R. Heidenhain: P.A. 17, 1878, 28. — 27. 
J.0. P. 9, 1888, 309. — 28. G. Marinesou: A.P. 1891, 357. — 29, M 
1864, 336. — 30, Th. Aschenbrandt: P. A. 25, 1881, 101. — 81. P. Gré 
1878, 522. — 32. A, Beck: ©. P. 12, 1898, 33. — 83. Eckhard u. Loob: 
uv. Physiol. 5, 1869, 1. — 34. FR, Miller: Quart. journ. of Physiol. 6, 
85. J. Pawlow: P. A. 16, 1878, 272, — 36, J.P. Parclow: E.P. 3, 1, 1904, 
957 u. 372, — 37. Lépine: G. m, 187, 382, — 38, Bary, Kerber; sh 
AP. 1902, 264. — 39. C. G. Mitscherlich: Rusts Mag. £. d. es, Heilk. 38, 18 
4, Physik m. Chemie (Poggendorit) 27, 1833, 320. — 40. J. P. Paclow: Dig 
dauungsdrisen. Cbersetzt von A. Walther. Wiesbaden 1898, — 41, L. Popie 
1909, 443. — 42. A.Scheunert y. A. Gottschalk: C. P. 28, 1909, 249. 



































In-Diss, Ziirich 1910, —- 43, B. v. Zebrowski: P.A. 110, 1905, 105. — 44. Br 
Fisiol. 8, 1911. — Eckhard: %, 1. M. (8), 29 1867, 74. — 46. Diem 





Kilnstlichen h — gewinnt man (berle 1834) darch Ex 
xerriebenen Magen *®*hleimhaut mit verdinnter Salzsdure, die 1 
von *, Liter von 6 at 8 Stunden stots anfs neue infundiert; [die spiteren 
sogar wirksamer ale deF erste (Aug *)), 

Die fir die Pepsinwirkung notwendige Salzsiure kann auch darch 
ganisehe and organisehe Siiuren ersatzt werden, doch sind von diesen hohere F 
erforderlich. Die Angaben der verschiedenen Untersucher iiber die von jeder « 
erforderliche Konzentration stimmen jedoch nicht fiberoin (Hibner™, | 


on, 

ve. Wittich® aeigte, dab man anch mittelst Glycerin aug der Ma 

des Pepsin sehr rein extrahieren kann, Die gereinigte Schleimhant wi 

in Alkobol dann getrocknot, gepulvert und gebentelt, hieranf eine Wor 

extrahiort. abiiltrierte Extrakt liBt durch Alkohol das Pepsin ansfulle 
Salzsiiuro gelést den wirksamen Saft gibt. 

Bel allen Extraktionsverfahron ist die Ausbeute an Pepsin am griBt 
Schleimhaut vor Piulnis geschiitzt einige Zeit an der Luft gelege 
sich noch nachériiglich in den Drisenzellen Propepsin und Pepsin  bilden 
Podwyasozki**). . 


110. Sekretion des Magensaftes. 


Wiihrend des Verlaufes der Verdauang gehen an den Ha 
und den Pylorusdriisenzellen (Hund) charakteristische histo lo; 
finderungen yor sich (Heidenhain', Ebstein®). 

Die Hanptzellen — xcigen Kirnchen, welche wiihrend der Absonder 
werden. Die Kirnchen enthalten die pepsinbildende Substanz, welche + 
facet wird. Anch die Gréfe der Hauptzellen sebwankt wihrend der Seb 

nehmen dic Zollen ans der Lymphe wieder Stoffe zur Kornchenbildw 
Relegzellon scheinen bei der Absonderung erst geschwellt, dann kleiner x 
Yellen sind ferner donkler, der Kern der Pylorusdrisenzelion riickt mehr in 
Sekretgiinge werden praller. — Die Belogzellen mancher Tiere tragen wiih) 
sonderung einen nach dom Lamen der Driise hin gorichteten Besatz kurze) 
Portsiitze (-Birstenbesate Torniors). 


Das Pepsin — wird in den Hauptzellen gebildet (A 
Sind diese geschwellt, so enthalten sie viel Pepsin; sind sie ; 
so enthalten sie wenig. Die Pylorusdriisen sondern eber 
auch weniger, Pepsin ab (Hbstein u. Griitzner™, Klug® u. a, 
des ersten Stadiums des Hungers wird das Pepsin angesamm 
der Verdauungstittigkeit (aber auch bei anhaltendem Hunger 

Kare nach der Nahrangsanfnahme ist der Pepsingehalt des Magensaf) 
ainkt er, um spiiter wieder zn steigen; ahnlich verhilt sich das Labfermen 
Hohmeier ™), 

Tanerhalb der Drtisen ist noch kein Pepsin vorhanden, 
eine Vorstufe oder das Zy mogen desselben: die ,pepsino 
stanz oder das .Propepsin® (Kbstein u, Griitener™), welch 
chen der Hauptzellen entsteht (Langley*). Das Zymogen ist 
sich unwirksam auf Eiweifkérper; wird es aber mit Siuren 
mit Salzsiiure) behandelt, so wird es in Pepsin umgewandelt; 
ae geht sehr schnell yor sich (Langley u. Edieins®*), Di 


freies Wasser kann man aus einer Magenschleimhaut neben 
zugleich die Paperoget Substanz ausziehen. — Auch das | 
in den Hauptzellen. 


Die Salzsiure — wird yon den Belegzellen gebildet (7 
sie findet sich auf der freien Pliche der Schleimbaut, & 
Ansty. ~1se4agen der Magendrysen. In der Viefe der Dri 

Tandolr- “toweic von, Physiologie. 14. Aya. 


sm suusenvordatung der Biweilkorper, 


mosen werden aus ihrer neutralen Lisung durch Stittigung mit Ki 
w jeden, di¢ Deuteroalbumosen dagegen nicht; sie fallen e 
gleiehzeitigem Zusatz einer Siinre aus. Die primiren Albumosen sin 
in reinem Wasser lisliche Protalbumose und die nur bei gleich 
art von Salzen lisliche Heteroalbumose, Die aus n 
primiiren Albumosen bei weiterer Verdauung entstehenden Deuter 
mosen zeigen untereinander nur geringfligige Unterschiede. 
Derch fraktionierte Fillung mit Ammonsalfat haben Hofmeister w 
eee eine noch weiter gehende Trennang der bei der Verdanung entstehenden 1 
ansgel 


Aus den Albumosen entstehen bei weiterem Fortgang der 
lytisehen Spaltung endlich die Peptone. Mit der Bildung der Pepto 
die Magenverdanung der Eiweibkérper ihren Absehluli erreicht; si 
nicht weiter bis zur Bildung von Aminosiiuren (vgl. 5. 269). Br 
Inge fortgesetzter Einwirkung des Pepsins soll allerdings die Sy 
doch bis zur Bildung yon Aminosiiuren fortsehreiten kénnen (Lang: 
Lewrow™, Salaskin u. Kowalewsky™, Kohlenberger®\; doch werde: 
Angaben bestritten (Abderhalden®*). 

Die Peptone sind noeh leichter léslich als die Albumos 
diffundieren leicht durch tierische Membranen (sie filtrieren 
leichter als Eiweif). Sie werden nicht gefillt durch Kochen, 
Skttigung mit Ammonsulfat, durch Salpetersiiure, Essigsiiun 
Kaliumeisencyantir, Essigsiiure und Kochsalzsiittigung. Dagegen w 
sie gefiillt durch Phosphorwolframsiiure, Phosphormolybdiinsiiure, ¢ 
siuren, Gerbsiiure (im Uberschu$ von Gerbsiiure lésen sie sich 
auf). Sie geben alle Farbenreaktionen des Eiweibes, spezi 
Natronlauge und Kupfersulfat in der Kiilte cine rotviolette Farbe (B 
reaktion). — Reines Pepton bildet ein amorphes, sehr hygrosko} 
Pulver, die Lisungen schmecken ekelhaft widerlich und bitter. 


Die Ausiriicke -Albumoson* und .Peptone* diirfen keinoswegs otwa uls 
nungen fir bestimmte, chemisch genau detinierte Substanzen anfgefabt werden; beide | 
stall vielmolr Gemlsche wehr verschiedenartiger ADbanprodukte dee Eivel di 
einmal die Vorstellang ist allgemein zutreffend, da die Albumosen Kirper von g 
Miolekil sind als die Poptone; nach Abderhalden™ ist os nicht notwendig, dab 
welche die Reaktionen der Albumosen zeigen, ein besonders groBes Molekiil besi 

t verhilinismabig einfach zusammengesetzte Polypeptide mit den Reaktionen der Alt 
‘Diese Reaktionen hingen danach nicht von der Grobe des Molekils ab, sondern » 
svon der Art and der Anordnung dar am Anfbau boteiligten Aminosiuren. 

Die bei der Magenverdauung wntstebonden Peptone werden yon Kahne als 1 
peptone boxcichnet (vgl. 8. 269). 


Darstellung reinen Peptons. — Die verdiinnte, von Albuminuten und & 
Jharen Stoflen befreite Verdanungslisung wird xnerst bei nahexn neutraler 
sicdend mit Ammonsulfnt gesittigt, kalt filtriert, — wieder erhitet, nach beg 
Sieden mit Ammoniak und Ammoniamearbonat kriftig alkalisch gemacht, abe 
der Hitze mit Ammoninmsnifat gesiittigt, — abgekiiblt filtriert, dann nochmals 
bis der Gerneh nach Ammoniak verschwunden ist, nochmala mit Ammoniumes 
gesiittigt, mit Fesigsiure angesinert, In der kalt filtrierten Fifssigkeit ist rein 
enthalten; nach Entfornung der Salze wird die Plissigkeit auf dem Wasserbade 
konzentriert und das Pepton mit Alkohol gefallt, 

Hydrolytisehe Spaltung der KiweiBkorper kann gnch durch Bebandlung 
mit Oberhitetem Wasserdampf, starkes m und Alkaljen sowie wach durch « 
mente (vel. 8.268) herbeigefihrt werd: 

Danilewsky" fond, dab, wenn man Lisungen ., Verdanungsprodulcten 
Jichem Magensaft oder Labferment bei Brutwirme aja. 0. hf fiogaes ned 
eine feste Gallerte entsteht; Sawjatow™™ nennt {eee sper Bierce 
Koagulose. Vielleicht handelt og sich dabel Uy) Be. gokbildane 

ne 





_ 
a 


Pan) seponraraaming der Riwoiblkiirper, Tesubs fenvent 


Neurokeratin, AMyloid. — Die Proteide werden unter der Ei 
des Magensaftes in ihre Bestandteile gespalten. So zerfiillt das 
lobin in Globin und Himatin; ersteres wird peptonisiert, 
leibt unveriindert und erscheint teils in den Faces, teils wird es re 
Die Glykoproteide (Mucin) werden in Eiwei6 and Kohlehydrat 
Die Nuneleoproteide zerfallen in Eiweif und Nuclein, welel 
Widerstandsfithigkeit gegen die Wirkung des Magensaftes 
as Nuelein kann jedoch zum kleineren Teil noch weiter in Eiw 
Nueleinsiiure gespalten werden; eine weitere pacientes der Nucl 
findet jedoch im Magen nicht statt (vgl. S. 269) (Umber "%, Abd. 
u. Schittenhelm '*), 

Abweichend gestaltet sich die Einwirkung des Magensaftes 
Casein. Dieses wird im Magen zuniichst in fester Form ausgefi 
bei es die Fettkiigelchen der Milch mit einschliebt). Die Ausfillu: 
bereits bewirkt werden dureh die freie Siure des Magensaftes. 
sein ist in der Mileh niimlich als Kalksalz vorhanden; wird ihm ¢ 
durch die Siiure entzogen, so fillt das unlésliche Casein als sole 


Es kommt aber im Magensaft noch cin besonderes Ferme 
das Labferment (Chymosin ), welches das Casein auch bei 1 
oder alkalischer Reaktion ausfillt (Hammarsten '** 1872). Dieser” 
hat aber mit der Fiillung des Caseins durch Stiure nichts zu tun. 
das Labferment wird niimlich das Casein hydrolytisch gespalten 
racasein und cine geringe Menge eines albumoseartigen aH 
Molkeneiweib (Fuld ‘*), Beide Kérper sind zuniichst lslich; di 
casein bildet aber mit Kalk unlisliche Salze, welche nunmebr als 
ausfallen. Werden die Kalksalze vorher entfernt, so tritt die § 
des Caseins in Paracasein und Molkeneiwei durch das Lab ein, 
Paracasein bleibt in Lisung. Setzt man nachtriiglich Kalksalze 
hinzu, so erfolgt nunmehr die Bildung und Ausfillung des Kises. 


Das Lab entsteht in den Haupteolion der Magendriisen durch Siiurnwiekung 
Labbildenden Substamz, Lotztere ist viel betrichtlicher in der Sebleimbat 
fertige Lab (Lircher™, Glisaner'®). Bin Teil Labferment kann 800000 ‘Tei 
Gillen. Znsatz von etwas Chlorealcium beschleunigt, yon Wasser versigert dic 
CHammarsten'™), Cherschul von Alkali schiidigt die Labwirkung (Johnson, 
Fxtemperer, Laqueur™), — Dos Labforment wird naterstiitet am be 
Bie Salasinee, ihr folgen nach ihrer Wirkung geordnet: Mileh-, Essig-, Seby 
F*hosphorsiinre (Pfleiderer"). 

tur Darstellung von Lab sebattelt Hammarsten'® ktinstlichen Kalb: 
x2ach seiner Neutralisierung mit Magnesiumearbonat. Im Filtrate ist nar Lab, we 
-Ansiiuren mit Essigsiiure darch Einschiltten yon fllssiger Stearinsiure geffllt wh 
zenhaftet. Letatere list man in Xther, den man leicht trennen kann. 

Die Labenzyme verschindenor Nerarton sind verschieden (Hedin 

Zwigehon Labfermont und eiweilspaltendem Furment besteht sowohl im 
CGrittener™, Winogradow™, Nencki u, Sieber) als auch im Pankrowssat 
Beziehung; dio Mengen dor beiden Fermente gehen vollatindig parallel. Atwne! 
Jhaben daher angenommen, da es sich therbaupt nicht nm awei  versshics 
handle, sondern um einen itlichen Kirper, dex augieieh ciwoiGepaltenc. | 
Wirkang habe; von and dies bestritten (ygl. Savjatow™*. Seu, 
Sacoby™, Gewin™, veh, Hammarsten®», Burge, Rakecsy" > 

Nachdem das Casein im Magen augge fal it, wntertiegt 

= Be ied gesyalter 

dauenden Wirkung des Magensaftes. Dabei wit & cere ast 
welches peptonisiert wird, und Paranuclei m- Das reer y 
islich, wird aber schlieBlich auch geldst unter PAWug ™ ‘o> 


orgunischen Siure, der Paranueleinsiur © (Salhot® 





130) 








ES 





{$1121 Absonderung des Pankreassnftes. 


ernont sich die homok2® Snbstanz, welche sich woiterhin wieder in hirnige Ma 
Hie dann wieder nxch Mnen tritt (Heidenhain'*, Bremer 

In dem 1. VeFduungastadinm (6.—10, Stunde) tindet ein Verbrauch a 

Innewzone und ein WaChstum der gestrichelten AnBenzone statt (Fig. 77, 2). Im 

a (10.80. Stunde) 

a1 geschwellten Driist 


tere wieder (Fig. 
dem paralytiseh 
renden, verklein 





reas ist die 

Vergnderungen dor Paokronssell jolene a 

Tisipuelts 1 ior Hungervortande, —"2 tr orton edie der Vers CC Seeehrmmptl 

davung, — ¢ im zweiten Stadium, — 4 bol due paralytischon Sekretion. (ie 7h i eH 

77, Je 

Zwischen den Drisenschliinchen liegen eigentiimliche Zellenkom plexe( Langer) 

Insoin), welche mit keinem Ausfuhrungsgnng in Verbindung steben; die Bedeutung 

ist noch nicht klar (vgl. 8. 286). 


Absonderung des Pankreassaftes. — Man kann beim | 
einen Ruhezustand, in welchem die Driise schlaff und blabgelb 
tinen Zustand der sekretorischen Tiitigkeit, in welchem das O 
schwellt und blabrot erscheint, unterscheiden, Bei der Absonder 
halten sich die GefiiBbe tihnlich wie die der Speicheldriisen nach 
reizang: sie sind erweitert, das Venenblut ist hellrot: es ist dalv 
scheinlich, daG hier eine ihnliche Innervation vorhanden ist (§ { 
Tiitigkeit der Driise ist in hohem Grade von der hinreichenc 
versorgung abhiingig, aniimische Zustiinde schiidigen die abso 
Vorgiinge (Pawlow*!, Gottlieb). Bei der Tiltigkeit der Dritse is 
wie bei den Speicheldriisen der Sauerstoffverbrauch und die Koh 
abgabe vermehrt (Barcroft u. Starling’), die Lymphbildung 
( Bainbridge '*). 

Das Sekret steht beim Kaninchen unter cinem Absonderangsdrne 


AT mm He. — Kohne w. Lea fanden, da nicht alle Lippehen 2a gleicher Ze 
ionstiitigkeit waren. (Dax Pankrens der Herbivoren secerniert ununterbrochen.) 





Die Absonderung des Pankreassaftes findet nur nach Na 
nahme statt, und zwar wird dieselbe veranlabt durch den Ube 
sauren Mageninhalts in den Darm (Dolinsky%, Pawloe 
Heim t. Klee™), Bringt man im Versuche Situren (80—50 ene® 
in das Duodenum oder Jejunum, so beginnt nach etwa 2 Mi 
lebhafte Absonderung des Pankreas; dieselbe dauert etwa 
nimmt dann ab und hért nach etwa 10 Minuten ganz auf. 

Uber die Art und Weise, wie diese Anregung des Pankr« 
tigkeit zustande kommt, gehen die Ansichten noch auscinsax 
Bayliss vu. Starling *° (1902) wird durch die Siiuren ein in dex 
des oberen Darmabschnittes gebildeter Stoff, das ,Prosekret io 
nimlich in .Sekretin* umgewandelt. Dieses wird durch & 
fife dem Pankreas zugefiihrt und regt direkt die Driisenze=% 
sonderung an, Dab die nervésen Elemente dabei nicht beveili 
auch daraus hervor, das die Wirkung des Sekretins auch 
vergiftang bestehen bleibt. 

Das Sekrotin 1i8t sich mittelst Sure (O4°/, Wo, oe 
vg). Stepp **) ans der Schleimhant des oberen Detandarmig ff a sake 


Cxtrabieren; bei intraveniser Injektion de# EXAK tag ena ¥* 


113. Der Pankreassaft. 


Zur GewinnuH® des Pankreassaftes — bund schon Regner de Gi 
tei Hunden in den Auslihrungsgang eine Kaniile mit einem Bltachen, in w 
Saft sich sammelte. Andere leiteten das Réhrchen durch die Banchdecken 1 
snd machten so eine transitorische Kanilenfistel. Aus einer solchen flieBt 
gleich nach der Operation so gut wie gar kein Sekrot; dag Pankrens scheint fy 
darch den Operationsreiz gesetzten Hemimung seine Arbeit fast ganz eingusb 
sucht man das ‘fier mit der Kantile am Leben 2u erhalten, so tritt mach 1—2 
bestiindige, tbermiiBige Absonderung eines dinnilisaigen, sebleeht wirksamen Se 
‘welches offenbar dem normalen Sekrete nicht entspricht. Noch che dieser Zustar 
wird dias eingcbundene Kantilenende entzindlich abgestoben und dio Fistel scl 
wieder. — Kine wirklich danernde Pankreastistel erreichten Palow™ u, Hei 
iadureb, da sie das Stick des Duodenums, in welehem der Punkreasgang m 
sohnitten und nach aulen in die Bauchwnnde einnihten. Kin so operiertes Pie 
sorgfaltiger Pileze (iie Banchhaut wird leiebt durch den austlielienden Saft mac 
pastender Ernahrang (Milch und Brot, dazi 2—5g Soda pro die) monatelang 
erhalten werden. 


Die Menge des im Tage abgesonderten Pankreassaftes ist 
nan bekannt, da bei den Tieren mit Pankreasfisteln unbekannte 
des Saftes durch Nebenausfiihrungsgiinge in den Darm gelangen 
so der Bestimmung entzichen kénnen. Auch wechselt die Menge 
Nahrung (vgl. unten die Tabelle nach Pawlow). Glaessner® ke 
einem Patienten die Absonderung des Pankreassaftes beobachten: 
ternen Zastande wurden 15—18 cm*, nach einer Mahlzeit 30—5( 
Stunde abgesondert. Die pro Tag secernierte Saftmenge schwankte 
500 und 800 em*. 

Der zeitliche Verlauf der Pankreassekretion zeigt in der 2.—3 Stunde 
Nahrungsanfnahme ein Maximum; im einzelnen gestaltet sich der Veelauf je naw 
geffihrten Nahrang verschieden (vgl. Pawlow, Rabkin", Wohlgemuth'®*), 

Der normale Pankreassaft ist durchsichtig, farb- und ¢ 
salzig yon Geschmack und besitzt infolge des Gebalts an Natriu 
bonat cin erhebliches Siurebindungsvermigen, bei Siturezusa 
er durch Abgabe von CO, auf. Von dieser starken Titrations: 
cenz ist zu unterscheiden die aktuelle Reaktion (vgl. § 11.3), 
cluerbach u. Pick” sich nur sehr wenig vom Neutralpunkte | 
einer_sehwach alkalischen Reaktion entfernt. 


Paelow ™ gibt folgende Tabelle aber die Zusammenseteung des Pankroa 
Hundes nach verschiodener Nahrung: 





























Menge Mittlore | Troeken Organ. 
Monge und Art| des Dauor | Sokretions-| ritek- | Asche! Su ‘ 
dor Nahrung | Pankrons- ier goschwin nd wane in 
‘safes Sokretion | digkeit (a |———!—_1___ x 
6 Minuten in Prozenton a 


























600 em? Mitel 45,7 |4 St. 80Min.| 0,85 em® | 5,268 )0,869)| 4,399 |0,68) 





250 9 Brot 1624 | 7St. 35 Min.) 1,75 om? | 3,228 0,025 98 |0,39 








1009 Fleisch| 131,6 |48t. 12Min,| 2,61 em? | 2,465 a 0.24 





Die Hanptmasse dor organischen Bestandteite syd Foecsuoryer, me 
am den Nucleoproteiden (de Ziliea)?, 2 sezanihy. 
Fir menseblichen Pankreasgaft (2 Portioney wien ‘Laan 
aweite Portion steht in Klammopn) gibt Glacwaneyry {Ee ne Re . 
997292 (98,7510), ‘rockensubstine S27? XL Rgqy, MSF 


safe. Soda witht OUF Ihmend, nicht sorsiorend, Salzsinre bewirkt 
Werno™). Durch Ethitten anf 65% wird dio Kuterokinase unwirksam 
Rérperemperatar wird “0 allmahlich zerstort (Vgl. aber das Verhalten yor 
sinogen umd Enterokina% gogentiber zorstirenden Fintlissen Metlandy a. 
‘Die Enterokinase kant durch yerdiinntes Glycerin (Vernon) over ( 
(Bayliss 0. Starling™*) wns der Schleimhant dos oberon Dinndarms extrab 

2 Aktives Trypsin vermag aus dem Zymogen weiteres Try 
anne Sele daber ¢inmal ein Teil des Zymogens in aktives Tryp! 
Ast, geht diese Umsetzung schnell weiter yor sich. — B Stark 
Jedoch diese Angabe; nach ihnen erfolgt die Aktivierung des a 
darch die Enterokinase. 

Die Umwandlung des Trypsinogens in aktives ‘Drypein orfolgt poy 
Darmsatt als auch durch das aktive Ferment nicht annihernd 99 schne 
‘wandlung dos Propepsins in Pepsin (vgl 8. 257) (Fernon™). 

3, Kalksalze haben nach Delezenne®® ine ausgesprochen aktivic 
uum besten bei einer Konzentration von ungefihy 0,5°),; stiirkere Konzentrat 
Fermentwirkang auf (vgl. Zwnz"’, Metlanby u. Woolley). 

4. Durch Liegenlasson der Driise an der Lmft, Verdannen der Extra 
wird das Zymogen in Trypsin umgewandelt. Bei Nekroxo cines Teils de 
‘weilen spontan beim Menschen, experimentell bei Tieren) entsteht ebenfalls « 
das bisher unwirksame Trypsinogen der Drise zu aktivieren vermag, so da 
verdanende Wirkungen in der Umgebung ausiben kann (Lattes*™*), — Dele 
auch wirksame Stoffe aus Bakterien, Schlangengiften, giftigen Pilzen. 

5, Die iiltere Angabe, dal die Milz auf die Aktiviernng des Pank 
BinilnB habe, ist von Prym* widerlogt. 

Tutrayendse Injektionen yon aktivem ‘Trypsin wirken bei Moers 
Kaninchon giftig (Krimpfe, Dyspnoe); inaktiviertas Trypsinogen ist verhiittn)) 
lich (Kirehheim™), 

Ill. Wirkung auf die Fette.*** — Die Fette werden zunii 
den Pankreassaft (auberdem durch die Galle, vgl. S. 293, un 
saft, vgl. S. 298) in eine Emulsion yerwandelt (Hberle*** 1) 

Enthilt das zu emulgierende Fett freie Fettsiure (was bei alle 
Nahrong dor Fall ist) und reagiort die Flissigkeit zugleich alkaliseh, so 0 
sionierung auferst schnell. Kin ‘Tropfehen Lebertran, der stots etwas frele 
0.3%, Sodaldsung gobracht, xerstiebt momentan in feine Emulsionskiirnche 
bildet sich an der Oboriliche des Oltropfons auerst cine foste Soifenhaut, 
uber schnell anf und os werden dabei kleine ‘Tropfehen abgerissen. Die 
bekleidet sich aufs neue mit cinor Seifendecke usw. (G. Quincke®*). Dio g 
‘wirken selbst wieder emulsionsbildend. 'Tierische Fotte lieforn teichter ot 
pilanzliche, das Ricinnsi! Aberhanpt gar keine (Gad*"*), 

Man nahm frither fast allgemein an, dai das Fett im | 
Emulsion als solches ohne weitere Verinderungen in 
resorbiert und in die Chylusgefiibe tibergeftihrt werden kénne. Na 
ist diese Vorstellung unrichtig: alles Fett mub, um resorbi 
zu kinnen, vorher gespalten werden (s. u.). Die Bedentu) 
sionierung des Fettes liegt vielmehr darin, da{ dadureh dj 
des Fettes auferordentlich vergribert wird; infolgedessen | 
Wasser unlisliche Fett mit dem in Wasser lislichen f 
Ferment (s. u.) in ansgiebige Wechselwirkung treten. 

2. Der Pankreassaft enthiilt ein Ferment, Steapsin « 

aunt, welehes die nentralen Fette spaltet in Glyeeria 
4iuren (hauptsiichlich Palmitinsiure, Stearinsiure ut 
daneben aber auch geringe Mengen niederer Fettsiuren). 
des Ferments wird durch Zusatz yon Galle stark erhiht ( 
Pawlow u. Bruno®™); wabrscheinlich handelt es sich dabei 1 
tivierung des in unwirksamer Form abgesonderten Fermen 
Galle (ntsprechend der Aktivierung des ‘Trypsinogens dure 
kinase, ygl. 5. 270). 


auf dem Umwege darch das Blut in den Darm bo inten (Abein 
Zunz n. Mayer***, Lombroso™ n. a, nebmen an, Pankreas 9 
‘eret noch auf andere Weise (innere Sekretion?) die Verdaunnge- und 
boeinflabt (von Burkhardé** bestritten), 


Literatur (§ 108—114). 


2 Asm. A, 6, 1870, 368. I. Hermanns Handbm 
tt: C. mW. 1870. Unters. ans d. Instit. £ 
. W, Zimmermann: A. m. A. 52, 1898, 552. ~ 
gender u, S. Laserstein: B.A. 55, 1894, 5 

@ . 805. Zeitschr. £. wissonsch. Zoolagi 
Pd a8, 198 G. Haane: A. A. 1905.1 
|. — 10, J. Disses Asm. A, 78, 1912, 7h. 





WH. Roeder: B. x. W. 1904, 1301. Sommerfeld: A... 1908, Supp 
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1805, & $55: — 2. Zusammontausonds Darsitliuag: Oloeseaies 
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a ‘Sallneskiz V.A. 70, 1877, 188. 81, 1880, 352. — 33. A. Bu 
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Bk. W. 1896, 383. — 43. Zawadzki: Ci, M15, 1804, Nr. 50. - 
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— 72. B. Linnqvist: 8. 4. 18, 1906, 194. — 
7. phe Ch. 03, 1909, 393. — 75, ci. Hersems* 
Sg R. Mark-Schnorf 1D A. 85, 1901, 143. — 77. Haan: 0.1. #¢ 
— 78. C.Radzikowski: P. A. 84, 1901, 513. — 99. Spiro: Me my 
80. Sehits: Prag. med. Wochonschr. 10, 1885, 193, — 81. W. Bue, 
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7 PA. 60, 1895, 543. — 204. F. Kohmann: B. d ch. G. 27, 1 
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130. Verh. naturhistor. med. Ges. au Beaders 2 N. P. 1, 1874, 195. 3, 188 
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264. — 217. EB. Abderhalden u. ¥. Teruuchi: %. ph. Ch. 49, 1906, 1. 
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890. Z. ph. Gh. 0, 1907, 497. 52, 1907, 412. — 231. Jochmonn u. | 





























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2 Bk. W. 1908, 1396. 0. Bergmann a. K. Meyer: Bok. W. 1 
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%. £ Hyg. 18, 88. — 237. Moye: Untors. physiol. Instit. Heidelberg 3, 378] 
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PA. 104, 1904, 483. 107, 1905, 599, — 204 1. Kirehhe 


























et DOL) Tan der Leber. 


Arteietchon begleitend) in Zeige der Pfortader einmlnden 
‘Srnrmwsgy eo! is sur Oberac der aber hervor, wwoselbst si0 me 
dor Peritonealhiille Weitmaschiges Netzwerk bilden. Die sich von hier an 
“Venenstitmmmehen gleichfalls an Pfortaderiistehen, 


3, Die Gallenglinge, — Dio foinsten a 
Centrom des Acinns her, und ebenso im dra Rema car sneer a 
(1=2u dicke), sehr rogelmaBig anastomosiorunde, gerade verlanfende Rokrehen, 
um jede Leberzelle eine polygonale Masche. Die Ritrchen liegen fast gtets in 
der Flaicho xweior benachbarter Loberzellen (Fig. 78. 0. @) als echte Inter, 
oder Sckretspalten. Beim Anseinanderfallen der Zellen durch tion verbleit 


Fig, 78, 












Hobolores. — V.¢ Vous centralis.— 
V, © Yona vaseularis, — AA A) 
grO0eren Gofibe tretend und wei 


boraellen verEw 
. — I Iolierte Let 
jallongang bildend, 


Zollon nur halbrinnenfirmige Kindriicke. Da die Blutexpillaren anf den Kanten 
‘xellonreihen verlanfon, die Gulleardhrehen jedoch anf den Flichen dor Zellen, s 
Robronsysteme stets durch dazwischonliegende Lebersellen getrennt (Fig. 79). 
Tnnerhalb des poripheren Rindenteiles des Lippebens vergriBern sich di 
Josen Robrchen durch Anastomosen benachbarter und verlasson sodann den Aci 
nun an interlobnllir (Pig. 78 g) sich mit den anstoBenden vereinigend, rib: 
anastomosicrende Gallenginge xn bilden, welche fortan in Bogleitung der Ast 
hepatica and der Vena portarnm schlieblich als Yuctas hepations die Laeberpfo 
— Die feineron interlobuliren Gallenginge bositwen eine Creede 
sit einem nicdrigen Bpithel. Dig geuberem Zelen eine ana Tinie 
Fasorn gowebte, doppolte Haut, djp inner *8teich We 





pe den 8 rice i chniei bert 
wr idia ter Spl*tchniet is ee 


azarae \ervorgernfen werden. Nach Cavazsani*® kann anch 
cooliacus die Zuckerbildung in der Leber angerogt worden. 

Nach Claude Bernard* wirkt der Zuckerstich in der Weise, dal dur 
des Centruns cine Erweiterung der Lebergefiife und Tem 
wodureh die Wirksamkeit des Fermenta auf das Giykogon sehr 
stellt sich singegen in Analogie der Verhiiltniase bei den Speicheldrisen ” 
Xn. splunchnict nicht bloS Gefidnerven ffir die Leber, sondern anch #0 
welche die Zuckerbildang in der Leber spexifiach beeintlassen, indem + 
ellen xu lebhafterer Produktion des Ferments anregen, 

n soll aber die Anregang der Zuckerbildung in der Leber be 
nicht in der Wolse stattfinden, da der Reix durch die Splanchnici d 
wird, die Anregang soll vielmehr darch Vermittelang der 
erfolgen, Der nervose Relz wird auf der Bahn des Sympathicus und Splane} 
‘en. den Nebennieren geleitet und bewirkt hier cine erhéhte Produktion ux 
Adrenalin (vgl. $192. TI) ins Bint; das Adrenalin bewirkt dann in der Lets 
tung des Leberglykogens in Zucker. Auch nach Injektion von Adrenalin tri 
ansschefdung im Harn auf: Zuckerstich- und Adrenalinglykosurie 
identisch. Nach Exstirpation der Nebennioren ist diher der Zuckerstich ¢ 
u. Starkenstein®). Auffallender Weise tihermittelt nur der linke Sympatl 
und zwar zonichst anf die linke Nebenniere, von hier aus gelangt er dure! 
bindungen zar rechten (Kahn", v. Noorden“), (Nach Gatin-Gruzeiwska™ } 
Adrenalininjektion Kaninehen glykogenfrei machen.) Anch fiir das % 
einer Reihe anderer experimentellér Glykosurien ist die Bedeutung der Neb 
pom. 80 flir die Glykosurie nach Koffein, Dinrotin, Strychnin usw. und 
ervenreizung (Pollak®), nach Asphyxie (Starkenstein™), — Allerdings + 
‘stellang, da8 die Zuckerstich- und andere Glykosurien auf dem Woge tber d 
dre Vermittlung des Adrenalins zustando kommen, anch manche Schy 
Wege (vgl. Bany®): im Blutsernn nach erfolgreichem Znekerstich ist kein 
nolingebalt nachwoisbar, es zeigt keine erhohte rasoconstrictorische Wit 
Negrin y Lopez), der Zuckerstich, ebenso dic Dinretin-Injektion kann ¢ 
hme da der Blutdrock steigt, wihrend bei intravendser Injektion von 
Giptomrie erst bei soleben Adrenalinmengen eintritt, die auch eine sehr 1 
rung bewirken (Trendelenburg vu. Fleivchhaner®), Wenn also a 
ggung der Nebennieren an dem Rintritt der Glykosurie nach Zuckerstich ur 
# ist doch die Art nnd Weise der Wirkung noch durchaus unklar. 

Mit dem Zuckercentram stehen cine grobe Zahl centripet: 
bahnen in Verbindung. Auf der Bahn dieser Nerven werde 
den von ihnen versorgten Gebieten ein gréferer Bedarf an | 
handen ist, Reize auf das Zuckereentram und von hier aus a 
libertragen, welche nun reichlicher Zucker durch das abfliebe 
den Korper abgibt. 

Reizung dieser Nervonbuhnen wird daher anf dem Wege dos Retle 
Yuokerbildung in der Leber und damit Zackerauescheldung durch den Har 
Hierher gebirt die Zockerauascheldung nach Durchschneidung des Vagus ode 
dos centralon Endos dos durchschnittenen Vagas (Cl. Bernard, Eckhard" 
contralen Endes des N. deprossor (Filehne"), Reizang dex Kopfstumptfes 
durchschaittenen Sympathicns (#. Kaz"), Durchschneidung und Reizung de 
(Schiff a. a, BE Kals™), 

Bin weiterer sehr bedeutungsvoller Kinflub auf die Re 
Zuckerstofiwechsels wird von dem Pankreas ausgetibt: ' 
stirpation des Pankreas hat einen ausgesprochene) 
zur Folge (v. Mering Minkowski7®, 1889). Wird nicht 

Pankreas exstirpieyt, so bleibt der Diabetes ans, falls das zurt 


ee 


Andere org #nische Bostandteilo: Fleischmilchsiiare, Lee 
daldes Uber eo, Cholesterin nur clpecaecae: goringe 
‘Harnsiure, Purim bason, Lencin, Cystin. — Die Leberzellen enthalten 


5. Anorganische Bestandteile: — Kalinm, Natrium, Calcium, 
— Chlor, Phosphor-, Kieselsiinre. (Kupfer, Zink, Blei, (uecksill 
Bestandteile gefunden worden; sie werden, wean sie in den 

werden, in der Leber abgelagert.) 


117. Die Zuckerharnrahr.” Experimentelle 6 


Die Zuckorharnrahr (Diabetes mollitns) stellt eine Stérang 
Verbiltnissen dos Kohlehydratstottwechsels dar. Es kommt dabei aur 
‘Traubenzucker im Harn (oft in sehr groBen Mengen; bis au 1 kg und d 
ulation: starker Vermehrung der Harnmenge (bis zu 107 und 

Kranken leiden infolge der erhdhten Dinrese an bestlindigem Darst 
lustes eines wertvollen Nahrungsstoifes (des Zuckers) an starkem Hunger. 
hydrate aus der Nahrang fortgelasson, so kann die Zackerausscheidun 
anfhiren, sogenannte ,leichte Fille”; in anderen Fallen bleibt sie aber ar 
freier Kost bestehen, sogenannte .schwere Fille” (vel. 8. 281). Kon 
nicht zum Stillstand, so tritt starke Abmagerung und schneller Verfall 

des Blutes (vgl 5.82) und der Siifte ist erhdht; er bedingt 

(Farunkulose, Hantjncken, Gangriin, Linsentriibang, Dispositic 

Im Harn kommt os zur Ansscheidung yon Accton, Acotessigaiure, 

echweren Fiillen wird zuweilen ein collapsusartiges Coma (Coma diabetir 
welchem der Tod erfolgen kann, 

Experimentell kann man Zuckeransscheidung durch den Har 
Weise erzongen; dio Ausscheidung von Zucker durch den Harn kann aby 
weiteres mit dem Krankheitsbilde des menschlichen Diabetes identifiziert 


1. Alimentiire Glykosurie, Nach sehr reichlicher Zofubr 
Nahrang tritt cine kurze Zeit anbaltende, guringfigige Znckerausscheidu 
ein. Die Leber vermag offenbar den reichlich xastromenden Zucker ni 
Glykogen abzulagern, cin ‘Teil gelangt direkt ins Blut (auch unter Us 
durch Resorption in die Lymphgofife, vel. $130.2), erhoht den Binten 
Norm und fiihrt so zur Ansscheidung dorch die Nieren. 

Digg Monge eines Zackors, die gerade genfigt, um alimentiire 
anfihren, als .Assimilationsgrenzo* bezeichnet. Dieser Wert ist fi 
bel verschiedenen ‘Tierarten, verschiedenen Indivyiduen verschieden; 0 
Individnum schwankt er nach den jeweiligen Umstinden, Die Assimila 
vorsehiedenen Zuckerarton ist ebenfalls verschioden: am hiechsten liegt 
facchariden (Tranbenzncker), am nicdrigston bei den Disacchariden, be 
aneker. Dies orklirt sich durans, da8 dio Disaccharide erst in die Monos 
werden mitsson, um von der Leber in Glykogen umgewandelt werden xt 
‘sio boi reichlicher Znfuhr zum Teil ungospalten ins Blut, so ktinnen s 
etwa noch im Blnte gespalten werden, wie 2 B. die Maltose, weder y 
yon den anderen Orgunen yerwertet werden and gelangen durch den Han 
(vgl. 8. 281). 

2. Eingriffe, welcho die Znckerbildung in der Leber s 
die normale Znckerbildang in der Lobor dhermabig gesteigert, so wire 
Frhihung des Blatanckorgchaltes cintroten missen, da den Organen m 
uls aie yerbrennen kinnen, und damit Zuckerausscheldnng darch den Hi 

Unter den Eingriffon, welche in dieser Woise wirken, ist an erste 
dor Zuckerstich Claude Bernards; durch diesen wird das die Zuckerbi 
anregende Centrum in dar Medulla oblongata direkt gerelat (ygl. $2 
die Roixang gewissor ‘Teil des Nervensystems, welche das Zuckercontt 
verbinden, sowie retlektorisch die Reizung centripotuler Nervyenbahnor 
Ynokerconteum in Verbindung stchen (ygl. 8-283). So ork\irt sich 
Yon Zacker im Harn boi Ischias und anderen Nervenieiden, Hine Be 

Uowirken dadarch Znckeransscheiding, da si¢ 408 Zuck¢reenteam i & 





In mensehlicher Galle (ebenso beim Rinde) tberwiegt die GI 
Hundegalle enthalt Uberhaupe pig reed At oe 


a) Die GlykOcholsiure — C,, Hy, NO, zerfaillt durch 
Kalilauge oder Barytwasser oder mit verdiinnten Mineralsiure) 
nahme yon H,Q in Glykokoll, Aminoessigsiiure CH 
COOH + Cholalstiure — (auch Cholsiiure genannt) C,, Hy, 


b) die Taurocholsiiure — C,, Hy, NSO, zerfillt bei 
hat unter Aufnahme yon H, O in Taurin, Aminoithyl 
CH, ) — CH, — SO, (OH) + Cholalsiure C,, Hy) O,. 


Darstellung der Gallensiiuren, — Galle wird anf‘), ihres Volume: 
sor Entfernung der Farbstoffe mit Tierkohls zu einem Brei verrieben 
getrocknet. Die schwarze Masse wird mit absolntem Alkohol ansgozogen, 
Jos abfiltriert. Nachdem man einen Teil des Alkohols dare Abdampfen verjs 
jm UbersebaG bingngesetater Ather die gallensauren Salze anfangs hi 






hare gehen eine Krystallmasse gliinzender Nadeln liber (Platners 
lisierte Gal 1844). Die so gewonnenen Alkalisalze der Gallen 
leicht in W. r oder Alkohol lislich, anlisiich in Ather, 


fosung der beiden Salze schligt nentrales essigeauros Bloi (Bleizncker) of 
Glykocholsiure roin nieder (als glykocholsaures Blei); letateros wird + 
gesammelt, in hoifem Alkohol gelist, durch H,S wird Schwofelblei ni: 
nach Entfernung des Niederschlages bewirkt Wnaserausatz das Ansfallon 
Glykocholsiiure. — Wird nach Ansfiillung dos glykocholsanren Bleies d 
Dbasisch-essigsaurem Blei (Bloiessig) versetzt, so bildet sich ein Nieders) 
rocholsaurem Blei (jedoch veranreinigt durch glykocholsaures Blei), aus 
in analoger Behandlung die freie Sinre gewonnen wird (Strecker), 

In der Rindsgalle und Menschengalle kommt noch die Gy kochole: 
G@ykokoll ond Oholeingiinre bestehend) vor, in der Hundegalle and Rinds 
rocholeinsinre (aus Tanrin und Choleinsiiure bestehend), in der Seb 
Hyoglykocholsiure, in der Ginsegalle die Ohenotaurocholsaiure, | 
Menschengalle noch die Fellingiure. 


Die Cholalsiure — C., Hy) O, ist rechtsdrehend, unlislic 
Wslich in Alkohol; in Ather ist sie schwer lislich und scheidet 
in Prismen ab. Ihre krystallinisehen Alkalisalze sind leicht s 
Wasser lislich. Mit Jod gibt sie cine im anffallenden Licht 
durehfallenden blane krystallinisehe Verbindung (Mylius*"*). 
sie nur im Darme vor (S. 292). Durch Kochen mit kon 
oder trocken erhitzt auf 200° wird die Cholalstiure zum Ant 
Dyslysin. 

Das Glykokoll (auch Glycin genannt) ist eines der 4 
des Biwei6 (hauptsiichlich des Leims) (vgl. 8. 10); im Harn 
Verbindung mit Benzoesiiure als Hippursiiure vor (§ 165). 

Das Taurin leitet sich yon dem schwefelhaltigen Spalt 
Kiweib, dem Cystin ab (vgl.S. 11). Das Cystin ist das 
Cysteins, dieses geht in folgender Weise in Taurin fiber: 


CH, — SH CH, — SO, (OH) CBs — 80, 

ihe —NH, —> a — NH, —» OH, — NB; 

COOH COOH . 
COystein. Cysteinsiinre, ‘Tauri. 


ee 
Friedmann" fibre Oystein in Tunrin ther; ¢. Bergmann’ 9" 


zeigten den Cbergang vou Cystin in Tanrin im tierisehen SPER os 
Die Pettenkofersche'* Probe (1844). — wie “eilt 
Cholalsiiure und ihre Anhydride geben gelést oder 20! 


| Wsa18) Die Gallenfarhstoife. 

yon oben nach Whten folgende Farbenringe: Grin ve, 
— Violett — Rot — Gelb. Die hierbei aiehen set ret 
dationsprodukte der Gallenfarbstofte. 


Der bei der Gmelinsehen Probe ontstehende lave Farbsto” wird als Billy 

der mat lotates Oxydationsprodukt ontstehende gelbe Farbstof? als Gholanln bo 

In Gallenstcinen sind anfer dem Bilirubin und Billverdin noch eine Reihe 
Gallenfarbstotte gefunden worden. 

Biliverdin soll in hetriichlichor Menge in der Placenta des Hundes yorkomm 


Das Bilirubin eit durch Reduktion (bei Behandlung der 
schen Lisung mit iumamalgam) unter Aufnahme von H, +] 
Hydrobilirabin, Cy HyoN,O,, tiber (in Wasser nur wei , leichter i 
fésnngen oder Alkalien, Alkohol, Ather, Chloroform Voslich). Umwa 
vollzieht sich regelmibig im Dickdarm durch ie Piuinis, das" 
bilirubin ist daher ein konstanter Farbstoff der Faeces, aus denen 1 
area mit Schwefelstiure durch absoluten Alkohol 

kann. Wahrscheinlich ist es mit dem Harnfarbstoffe Urobilin id 
oder nahe verwandt. 


Auber don sperifisehon Gallenbestandteilen: 
kommen in der Galle noch yor: 

8. cin xchleimahnliches Nucteoalbumin (Paijkull™), abor auch echtes 
(Hammarsten*, Cacazzani*); si@ machen die Galle tudenzichend. Sie stammen 
Schleimdrisen der Gallenwogo and der Gallenblase; durch Alkohol oder verdiinnte 8: 
Essigsfiure werden sie gefillt, 

4. Cholostorin, Cy, Hy, 0 (vel pag. 20). Ex bildot glashelle rhombische 
(Fig, 62, 4), ist unldslich in’ Wassor, Wslich in heifiem Alkohol, in Athor oder Chi 
In der Gally wird es durch die gallensanren Salze in kolloidaler Léiaung erhalten. 

Am infuchsten wird es aus sogenannten ,weion Gallenateine 
gestellt (die nicht selten groBentoils aus fust reinem Cholesterin bestohon), indi 
Hie zerreibt und mit Alkohol nuskocht. Die bei Verdunstung des Alkobols sich nbseh) 
Keystalle firben sich mit Schwofelsiure (5 Vol. 2u 1 Vol. Wasser) vom Rands aus r 
violett, — mit Schwefelsiure und Jod violett, blan und grin. 

5. Lecithin (vgl 8.21), Fetto, Seifeo, Atherschwefelsiuren, gupaarte G 
siuren, Sparen von Harnstofl. 

6. Anorganische Bostandteile; Chlornatrium, Chlorkalium, Caleium- uné 
siomphosphat und wechsetnds Mongen von Risen, endlich otwas Mangan und Kiq 
able fitch abenconderte Calle eniht bein Hinde, ther 60, tein Kaninchen 

Prlager™, Charles™), teils an Alkali gobundone, tails absorbio 
Jaubese wisd ‘Scortild cr Blase fast vallig-remarblect, 

Analysen monschlicher Loborgallen (nach Hammarsten™, vgl. By 

e.Ceyhlars, Fuchs 0. ¢. Firth), 


Gallensiiuren und Gullenfa 
























Festo Stoffo . wt 25,200 35,260 25,400 
Wasser. 974,300 964,740 974,600. 
Mucin und Farbstow . . 5.20 4,290 5,150 
Gallensaure Alkalien . . 9,310 18,240 9,040 
Tanrocholat . 2... 3,034 2.079 2,180 
Glykocholat . 6,276 16,161 6,860 
Fottsiluren ans Scifen 1,230 1,360 1,010 
Cholesterin .. 0,630 1,600 ay 
Lecithin... 574 
ee Jo220 oars 0,610 
Lisliche Salze . 8,070 6,760 7,250 
Unldalicho Sale 2]! 0,250 0,490 O20 
3 Biat) 
In dic Gallo gohon verschivdene Substanaem, welche die 
sleren, liber, so 2. B,: dio Motallo, die auch im Leborgewebe Geponiers Sy 
8.285); Jod-, Brom-, Rhodankalivm, chlorsanres Kalium, AtS®%s cant oy 
gespritate Galle (anch dio anderor Tiere), salicylsanres Notringx» 


Methylonblan, Robr- und T'raubensucker, Athyly Amylalkehol (aaP°S ” el ‘Jom 
bores Eiweif in der Galle auf) (Prérost a. Binet ™™, Brauer #2" )- ae 
boi Pankreasdiabotes ist die Gallo zuckerhaltig, nicht jedoc®* 
(Brauer). 


Landois-Rosemann, Vhysiologip, 14, ABM 














{teichliche nx14 miglichst schnetle Durchstrdmang wirkt am vorteilbafte 
Absonderang: Hiertyed kommt der herrsehends Blutdruck nicht in erster Linie 
denn die Ligatur dex Cav inferior oberhalb dex Zworehfelles, wodurch in de 
hiehste Stauungsblutdruck eich entfultet, sistiert die Sekretion (Heidenhain 
fusionen Bintmengen vormehren stets die Gallenbildung (Landois'**), 1 
Drnck in der Pfortader durch Kinleitang des Carotisblates eines anderen ‘Tiare! 
beschritnkt sie (Heidehain '*), 


3. von dem Umsatz der roten Blatkirperchen — we 
— in der Leber (§ 16) das Material dazu 


Alle Eingritfe daher, welche stiirkere Einschmelzung roter Blutkorperche 
machen die Leber Hb-reich und haben vermehrte Gallenbildung zur Folge (j 
pathologisch, z. B. bei Malaria und Blutzersetxongen. 

4, yom Nervensy stem. — Alle Eingritte, welche die arteriellen Gefid 
Ieibes verengern: izung der Ansa Vieussenil, des Ggl. cervicale inferins, der 
des Splanchnicns (J, Munk'*), des Riickenmarkes (direkt durch Strychnin, oder 
dureh Reizung sensibler Nerven)}, becintrichtigen die Absondernng. Ebenso 
Fingriffe, welche cine Stagnation des Blutes in den Lebergefigen bewirken, 
(pag. 282), Durebschneidung des Halsmarkes. Durchschneidang der Nn. splanch 
Bee der Erweiterung dor Unterleibsgefife Vermebrung der Gallenabsondern 
hain 4), 





Kinige Stoffe sollen die Absonderang der Galle beférdern (Chola 
vend], ‘Torpentinil, salicylsaures Natriam, alkalinisehe and abfihrende M 

wivgen ist die befirdernde Wirkung der Galle and gallonsauren Sa 
bie), — Nach Injoktion ron Sekretin ins Bint wird nicht nar die P 
sondern anch die Gallenabsondernng angeregt (vgl. S. 266). 

Der Druck in einer mit den Gallenwegen in Verbindung 
Glasréhre steigt bis auf 200 mm (Meersehweinchen, Hund, K; 
wird der Druck noch weiter erhiht, so erfolyt Rtick-Resorp 
Galle, erst in die Lymphwege und durch diese ins Blut (vgl. Tkte: 
(Heidenhain**, Biirker *). 

Die Galle wird kontinuierlich abgesondert, auch wit 
fitalen Lebens, aber teilweise zuniichst in der Gallenblas 
speichert und zur Zeit der Verdanung reichlicher in den Darm 
Der Austritt der Galle in den Darm steht in Zusammenhang 

yehischen Reiz der Nahrangsaufnahme, ferner ganz besonders 
rtritt der Speisen in den Darmkanal (Klee u. K7iipfel). 
schiedener Nahrung ist nicht nur die Menge und Zusammense 
Galle, sondern auch der Verlauf des Galleaustritts in den Darm ve 
Es handelt sich dabei um einen Reflexvorgang, der von der Sc 
des Dnodenums ausgeljst wird; als Erreger der Galleausscheic 
nachgewiesen die Produkte der Eiweifverdauung und die Fette 
Wasser, Salzsiiure, Soda, Stiirke in dieser Beziehung wirkun 
(Babkin**°), 

Dio Gallenblase und die Gallengiinge besitzen glatte Ring- und TLAngsm 
Contraction das Sckrot weiter befrdert (Bainbridge u, Dale!), Der motorit 
der N. splanchnious. Auch durch Reizung dos eentralon Vagus- oder Ischia 
kann die Bewegung der Gallenwoge teil errogt, teila gehemmt werden. An 
dungastelle des Dactos choledochus in den Darm (Papilla Vater?) Lapa 
firmige, aus glatten Fasern bestohende Muskellage, die yon der ObriKe 
getrennt ist and als Sphincter wirkt (vel Rost #*), 

Im Darm werden von den Gallenbestandteih 
sorbiert, andere mit den Faeces entleert, g\exot 

Die Gallensiiuren werdenzum grohtenT © * na 
des Jejunums und Teums wieder resorbier® ar we fe 
aufs neue verwendet (Gallenkyeis!®™)- Tappeine= 








en singe 







n nahin Srther vielfach an, dal auch ohne di 
Man. Bt in an chee e Lehst 
Im Gegensitz zu diesem sogenannten himatogen 
“Tkter behiwelehem in der Laber geblldete Galle Ins Blut ge 
4a 


i Chats LB Toa soge:Taloe heretaioincien emt 


‘Darm gelangt), — fettreich (well die Fotte ohne Galle im 
P bis 78"), des 


‘ en vorwiegend Fetisinren und Seiten in den Faeces, 1 
und sehr stinkond (weil unter normalen Verhiltnissen die in 
faulige Zersetaung des Darminhaltes einschrinken soll; di 

sehr xweifelhaft). — Die.Kotentleerung erfolgt tr 

teils wegen Fehlens der die peristaltischen Bew 


Le |. Der Herzschlug wird bis gegen 40 Sehliige in 1 
rihet her yon den rep Salzen, welche das Hors xuert 
Be — Neben der Einwirkung auf das Hers zeigt # 
Kleinsten Blutgefibe, — Verlangsamung der Atm 
Vom peratur, 
5. Bine anf das Nervensystem, wabrschy 
lensauren Salze, vielleicht auch anf die Muskeln, zeigt sich 
4 nung, Midigkelt, Schwiiche und Seblatsucht, endlich tie! 
 Schlaflosigkeit, Hautincken, selbst Tohsacht und Krimpfen. 
} 6. Bei hochgradigem Ikteras entsteht Gelbachen (Lue 
Amprignation der Netehunt mit gelbem Gallenfarbstot, 


121. Wirkung der Galle, 


A. Die wichtigste Wirkung, welche die Galle 
ist ihr EinfluS auf die Verdanung und Resorpti 
1. Die Galle wandelt (ebenso wie der Pant 
die neutralen Fette in eine Emulsion um; indem hi 
des Fettes stark vergréfert wird, wird die Einwi 
léslichen Steapsins des Pankreassaftes auf die in Wi 
wesentlich instigt. 
2. Auf das emulsionierte Fett wirkt nunmehr | 
Krenssaftes (die Galle selbst hat keine fettspaltende 
in Glycerin und Fettsiiuren, Das Glycerin ist in \ 
ohne weiteres der Resorption fithig. Die Fettsiiuren sin 
unlislich; sie werden nunmehr dureh die Galle 

\ dem Alkali des Darm- und Pankreassaftes i 

_ lichen Zustand tihergefithrt (Pfiiger™). 

} Nach Moore u. Rockwood" losen 100 em? frische alli 
Olsiinre. Plager ™* bestiitigte diese Beobachtang, zeigte aber w 
Maximom dor zngesetzten Olsiiure orst dann Wat, wenn ihr ¢ 
Monge Soda angesetet witd: 100 cm? Galle Wisen alsdann wenig 
Gogonsatze dazu Wst Galle von Palmitinsinre und Stearinsiny 

| —praktisch so gut wie nichts, Wirkt aber Galle anf ein Ge 

oder Steurinsiinre mit Olsiinre bei Gegenwart der aquivalente 





193267 Ver UMS 


Bei Gallentistelt#reu und bei Behinderung des Abflusses der Gal) 
Darm liegt die Peristaltik sehr darnieder. 

E. Beim Wintritt des stark sauer reagierenden Mageninh 
das Duodenum werden die gallensauren Salze zerlegt, es ent 
Niederschlag von Gallenstinren und Eiweib, der auch das Pepsin m 
reift. Auch durch das Abneutralisieren des sauren M all 
eine weitere Wirkung des Pepsins im Darme gehindert. 


Wenn Galle in den Magen tritt, so wird dadurch in gleicher Weise | 
mung becintrichtigt werden; sobald aber wieder nener Magensaft abges 
wird die Verdaunng fortgesetzt werden. 


122. Der Darmsaft. 


Der Darm des Menschen ist 7mal so lang wie die Kirperlinge vom S 
gum After (der Darm der mebr Pflanzen essenden Asiaten ist um '/, linger). 
und die Kapazitit des Darma ist bei Kindern relativ am griften, Der Minne 
etwas Iinger als der der Weiber. — Der Darm der Herbivoren ist linger al: 
Carnivoren, Bei Froschlarven stellte Babdk*™ fest, daB Pflanzenfitterung eine | 
¥ des Verdaunngskanules gegeniiber Fleischfiitterang hervorruft. 
Menschen kénnen 2-4 m Dorm roseziert werden, ohne da dadurch eine Gefal 
Patienten enitsteht; allerdings ist die Darmtitigkeit, besonders die Resorption bee 
(Sehlatter™™, Storp™*, Arhausen*™), Hunde ertragen noch die Wegnahme y 
Dinndarms (Erlanger v. Hewlett), 


Der Darmsaft (Suceus entericus) ist die von den zal 
Dritsen der Darmschleimhaut abgesonderte Verdauungsfltissigk: 
‘ibte Menge derselben liefern die Lieberkithnschen Driisen; oben 
um wird dazu das spiirliche Sekret der Brunnerschen Driisen ¢ 


Die Brunnerschen Driisen — finden sich beim Menschon nur verein 
Sehafé in kontinuierlicher Schicht im Duodennm. Thre Zellen stehen denen de 
drigen nahe. Wihrend des Hungerzustandes sind sie grof nd hell, wihrend 
dannngstitigkeit klein und trib (Grifzner‘™); die Driisen enthalten, obensc 
Pelorusdrisen des Magens Granula (Schirathe™*, Bogomolets"*), Thr Sokret 0 
dom Pepsin analoges ciweiflisendes Ferment; bei alkalischer Reaktion ist es t 
(Fonomaree™, Abderhalden vw. Rona), Beim Pferd, Rind, Schwoin konnte 
Scheunert u. Grimmer* keine proteolytieche Wirksamkeit des Sokretes der Bru 
Driisen nachweisen. 


We Lieberkiiinschen Driisen — sind einfach-schlanehfirmige Driisy 
aight nebonoinander in der Darmschlcimhant, und 2war am reichlichsten in der 
arms (wegen des Fehlons der Zotten) vorkommen. Sie besitzen eine avs feinston 
gowebto Mombronn proprin und cine einschichtige Lage cylindrischer Drise 
awischen denen anch Becherzellen vorkommon, spiirlich im dimnen, sebr roi 
dicken Gedirme; die Dinndarmdriisen lieforn vorwiegend dines Sokret, die des } 
ans ihren zablreichen Bechern zihen Schleim (Heidenhain n, Klose). — 
der Lisherkihnschen Drfigen ist vom Duodenum an abwirts der Hauptbesta 
Darmsattes. 

Der Darmsaft wird nach Thirys™ Mothodo (1864) In folgender Weise 
Darmfistel — xewonnen. Aus einer hervorgozogenon Darmschlinge des Hundes w 
awei Scbnitte sin handlanges Stick so getrennt, da8 mor das Darmrobr, nicht 
Mesenteriam durebschnitten wird. Dax cine Ende dieser Strecke wird xngebur 
andere offen in die Banehwnnde eingendht, nachdom vorher die Endon des 
ayisehen denen die Strocke ansgeschaltet war, durch Nabte sorgfaltig wieder 
wordin sind. Vella’ (1881) liBt beide Endon des hnfeisenfiirmig umzxublegen 
siickes auf der Banchwand ausmiinden. Auf diese Weise kann das ‘Tier nach | 

jon mit seinem nur wenig verkiirzten Darme weiterleben. Die nach | 
mindande Darmfistel aber gibt einen durch kein anderes Verdanungssekret vor 
Darmsaft. — London '** hat bei Hundon im Vorlaufe des Darms mebrere Fisteln 
(Polyfistolmethode); nach Spoiseznfuhr fijeBt dann was dea ob e T 
bret it Maget-, Pankrenseatt, Gulle ab, wahrend die wateren Fistela Warm 














reaay ~senaugen Wes LaATMmsuItes. 


= Fettm, i 
Die Zuiuby grober engen in der Nahrang bedingt nach Pl 
| sare Reaktion des Diinndarms, indem das Alkali des Pankreo 
Darmsafies bei der Verseifung der freien Fettstiuren verbraucht w 
Bei Pflanzenfressern reagiert nach Bidder u. Schmidt*** die Dim 
schleimhaut gegen Lackwus alkalisch, aber der Darminhalt sauer 
dureh die G&rung der Kohlehydrate, ygl. S. 300). Gegen kohle 
empfindliche Indikatoren, z. B. Phenolphthalein, reagiert nach 1. 1 
der Diinndarmehymus bei Carni-, Herbi- und Omniyoren schwach 
oder fast neutral. — Im Dickdarm ist meist saure Reaktion weg 

sauren Giirang des Darminhaltes. 

1. Wirkung auf die Kohlehydrate. — Der Darmsaft 
diastatische Wirkung, aber in geringerem Mage als Speichel un 
Kreassaft (Hamburger '", Mendel'**, Hamburger u. Hekma™, Nage 
Die Wirku des Darmeaftes auf die Polysaccharide kann dat 

i fies Dageren enthiilt der Darmsaft sehr wirksame Fermente, 
Disaccharide in Monosaccharide ttberfiihren, und zwar; 

1, Maltase, welche Maltose in Dextrose tiberfiihrt (Pant: a. Vi 
Hamburger’, Mendel*, Nagano), Dieses Ferment setzt also d 
statische Wirkung des Speichels und des Pankreassaftes, welche im + 


Pig. #2. 






— Drtisenepithel 





Hohiranm der Drtren- — Bindogewebe 


wchlauche 
Gefaie 


Querschnitt Lirberkahascher Drisen. 


Tichen nur Maltose bilden, fort. — Wird etwa unverdnderte Maltose res 
so kann sie noch durch die Maltase des Blutes (ygl. 8. 83) in D 
gespalten werden. 

2. Invertin, welehes Rohraucker in Dextrose und Liivalose 
(Miura 2°, Pautz a. Vogel, Mendel***, Nagano '"?, Rékmann**). Das F 
‘ommt nur im Ditondarm vor, nicht im Dieckdarm. 

3. Lactase, welche Milchzucker (Lactose) in Dextrose und 
tose spaltet, kommt gewohnlich nur bei Tieren yor, die in ihrer N 
Milehzucker aufnehmen, und zwar im Diinndarm junger (saugender) 
tiere und des Neugeborenen, ferner bei den Omnivoren, Schwein wnt 
nicht beim erwachsenen Rind, Schaf, Kaninchen, Huhn, dagegen 1 
wachsenen Pferd (Weinand**), Warden Kaninchen vom Siiugli 
an mehrere Monate lang fortgesetzt mit Mileh gefuttert, so WaT ™ 
dauernd Lactase bei ihnen vorhanden. 

Im Footus tritt das Invortin zuorst anf, am Anfang gos 4- Menats, die ? 
Ende des 4.Monats, dio Lactaso dagogen erst im 7. bis 8. Monat (£Brahin w- Kow 

2. Eine Wirkung auf native Eiweibkirper pesitat es 
nicht. Dagegen wies Cohnheim2 in Extrakten der Darms 
Kiutseher u. Seemann ®®, Salaskin®°*, Hamburger u. ekma'* auch 
saft ein besonderes Ferment ,Erepsin*® nach, welches, vor ey 
Ferchieden, die echten Eiweibkiper nicht avgreift, aber die 


[e124) Die RiweiSfiulnie im Darme. 


rt nicht iMer ein Harn, der reich an Phenyhchwefelsin 
Seve Indies cothanee = 


3. Aromatische Oxysiuren: Paraoxyphenylessigsiture 
GH, <o, COOH — Paraoxyphenylpropionsiiure (Hydroparacumar 


OH, oo _ cat, .coon emtstehen ebenfalls bei der Piulnis des ‘Ty 


and sind auch im Harn nachgewiesen. 
Der stufenweise Abbau des Tyrosins wird durch folgende Fo 
wiedergegeben : 


‘Tyrosin, p-Oxyphenylaminopropionsiiure C, Hor — CH(NH,) .¢ 
y p) .€ 
p-Oxyphenylpropionsiiure ©, H, Or —CH, .COOH, 
p-Oxyphenylessigsiiure (, H, ae — cooH 
, 


p-Kresol G, Hy ee , Phenol C,H, -OH. 


4. Nur unter pathologischen Bedingungen (bei der Cysti 
bei Cholera, Dysenterie und akuter Enteritis) entstehen im Darm, 
scheinlich infolge abnormer Fiulnisvorgiinge Diamine: Putresein ( 
methylendiamin, C,H,,N,) und Cadaverin (Pentamethylendiamin, 0, H 
(Baumann u.v, Udrdnszky***); dieselben treten dann auch in den Harn 

Das Putrescin leitet sich ab von dem Ornithin des Riv 


(vgl. S.11): 
OH, (NH,) — CH, — CH, — CH (NH.) —COOH = 
Ornithin, Diaminoyaleriansinre 
= CH, (NH,) — CH, — CH, — CH, (NH,) + CO0,. 
Putrescin, ‘Tetramethylendiamin, 
Das Cadaverin entsteht ebenso aus dem Lysin des Eiv 
(vgl. 8.11) (Allinger #9), 
CH, (NH,) — CH, — CH, — CH, — CH (NH,) — COOH = 
Lysin, Dinminocapronsiure 
= CH, (NH,) — CH, — CH, — CH, — CH, (NH,) + ©O,. 
Cadaverin, Pentamethylendiamin. 
Im Darme des Foetus und des Neugeborenen fehlen die Finknisprodakte (Sena 
im Stiuglingakot fand Blawberg*” kein Indol, Skatol, Phenol, dagegen deutliche B 
auf Oxysinren. — Belm Erwachsenen weehselt die Menge der Fiulnisprodukte ats 
nach der Art der Nahrung, der Intensitit der Darmfilnlnis und der GriBe der Rew 
Durch Koblehydratreiche Nahrung, noch besser durch reine Milchdilt kianen sie ex 
doch fast villig zum Verschwinden gebracht werden (Wintermits*%), ebenso auct 
sturke Abfiihrmittel, namentlich dureh Calomel, nicht aber durch die verschiedenen #° 
ten Darmantisepticn (Albu™*). 


124. Vorgiinge im Dickdarme. Bildung der Faeces.’ 


a ag 

Innerhalb des Dickdarms ttberwiegen die Fiwulnis- un 
zersetzungen die fermentativen oder eigenthichen Verione 
pasar eelir geringe Mengen der Darmsattferments a darm 
werden, Auberdem ist die aufsangende rr wtige et alles, Sach 


eriiver als die absondernde, dig Konsisten de 


was ae 3 ee ae 

wasserreichete Feces, die Menge anfgenon 
"Chery, flu, —— Je schineller ferner die Peristalt 
sind die Faeces, weil nicht hinreichend Zeit 


Che, vorrtickenden Ingestis Flissigkeit zu resorb 
Ret at De Re lend ist oft sauer, a 
be Garang ©) “ate entstandenen 

ing doch im unteren Darmabschnitte aur Bild 


so kann neutrale und selbst alkalische Reak: 
sonderung von Schleim im Darm beglinstig 

Die Farbe — riehtet sich nach der 
iinderten Gallenfarbstoffe. 

AuBerdem wirkt die Farbe der Nahraungsm 
der Nabrang macht die Faeces fast braunschwars dary 
durch die Darmfiininis zu Hiimochromogen reduziert, 
= griine Vegetabilen braungriin arch Chlorophyll; . 


Vig. 88. 









Faecos: 9 Muskelfusorn, b Sena, ¢ 
Piaurensclion, daewisehon wborall m 
phoreures Ammonitinmas 


t; — blaurote Pflanzensiifte blanschware; 
Bildung von Schwefeleisen (teilweise) schwarz. 

Die Facees enthalten (siehe Fig. 83): 

1, Die unverdanlichen Riteketiinde der Gewebo 
Fmittel: Haare, Horngewobo; — Cellulose, Holzfasern, 
=eellen, Gummi. 

2. Bruchstiicke sonst woh! verdanticher Subst 
Bhergroler Menge genossen waren oder durch Kauen 
erfahren hatten: Fleischreste (bis 1%,), Schinkenstiick« 
etxen, Knorpelstickehen, Flocken von Fetteewebe, elas 
or Darmachleimhant, — ferner Pilanzenzellen: Sticke 
reifor Hlsenfrichte, unzerriebene Kicberzellen des Ge 

8, Nuch sehr reichem MilchgenaS, ebonso nw 
Kote Krystalinadeln von fottsaurem Kalk, Katkat 
Klumpen von Casein und Fett auftreten. Reichere F 
schlochtere Verdanung und Ausnutzung des Fettes bi 
Hes Pankreassaftes). 

4. Uber den Chergang von Gallenbestandt 
Parinbasen tinden sich in den Fueoos mehr als 4 
Harnsiiure kommt fast regelmiBig jm Meconium > 

der Facces stammen znm kleingten Teil Mo 
Sanpisiichlich aus abgestobenen Darmepithelie = 


= 






qpereres 


£5 
es 


gaat nm meen AT SETI Oe 


5. J.J. R. Macleod uw. BG. Pearce: A. J.P, 25, 1910, 235. — BI. BL 

52, Cf 471. Z. B. 60, 1913, 371 0. 388. M, m. W. 1913, 311, — 52. Arthas 

Gur, soc, biol, 4M, 1889, 674. "A. d.P. 28," 1800, 168. — 53. a. 

1894, 656. — D4. Doyon uw. Dufour: ret 1901, 703, — 55. Cl. Berm 
cours du semestre dhiver 1854-55), 8. 289. — 5G. Kekhard: Beitiige 
Physiol, 4. 1869, Jl, 138. 8, 1879, 77._—_ 57. Cl. Bernard: Tecons sur 

. *. Dock: P. A. 5, 1872, B71. — 59. B. Carazzan 

1881) 181. — 00. E. 

EB, Starke 








Pfliiger: oben unter 7., 8. 393 0.394. — BL B. 
nstein: P. A. 130, 1911, 181. — 62. ELH. Kahn: P. A. 140, 191) 
1912, 251, 896. 146, 1912, 578 — 63. ©. Noorden: M. K. 7%, 1911, 1. — 64 
Gruzewska: C. 1.142, 1906, 1165. — 65. L. Pollak: A. P,P. 61, 1909, 376 
Ho Pow T. 10, 1912, 78. — 67. J, Bong: Der Bluteucker. 
1913, 5.98 — 68. J. Negrin y Lopez: P. A. 145, 1912, att. — 69 P. Tr 
un, AL Bletachhauer: Zeitschr. f. d. ges. exper, Med. 1, 1913, 369, — 70, Ch Ber 
unter 5 |. 325. — 71, Kekhard: Beitrige z, Anatomie u, Physiol. 8, 18 
72. Filehne; C, m, W. 1878, 321, — 73. BE. Kitlz: P. A. 24, 1881, 109, — 
Journ. de Uanat, et de In physiol. 3, 1866, 354. Minkovesl 
mellitus mach Pankreasexstirpation. Leipzig . 26, 1: 
ee es tiher den Diabetes mellitus. Leipzig 1893. — ib. Wes 
1892, 86. — 77. Zusammentassende Darstellung: S. 
Handbuch der Biochemie. Jena 1910. 3, 1, 245. — 78. LU. Lombroso: 
79. FP. Knowlton a. &. A. Starling: ©. P, 26, 1912, 169. J.0. P. 4, 1912, 1 
1912, 218. SW. Patterson u. EH. Starling: J... P. 47, 1914, 137 
Cruickshank u. &. W. Patterson: J. 0. P47, 1914, 381, — 80. E. Pliiger: PLA 
265 u. 267. 119, 1907, 227, 122, 1908, 267. 123, 1908, 323, 124, 1908, 1 n 
1909, 125. A, Herlitzka: P. A. 123, 1908, 331. — 81. 0, Minkowski: A. PLT 
QU. Re Ehrmann: PA. U9, 1907, 295. 124, 1908, 237. S. Rosenberg: P. 
358. B.%, 18, 1909, 99. E. Tacherniachowski: Z. B. 53, 1910, 1. 
PA. 118, 1907, 271. — 83. FE. Leschke: AP. 1910, 401. — 84. 0, Minkows 
1892, 90. — Si Hédon: OC. r, 11D, 1892, 292. ©. r. soe. biol. (4) 9, 1892. A 
‘Travaux de pian Paris 1898, — 86, Eppinger, Falta uw. Rudinger: 
1908, 1. — 87. E Drechsel: J. p. Oh. N. a, 1886, 425. L. B, 88, 188¢ 
83, 1896, 85. — 88. J, Meinertz: %. ph. Ch, 46, 1905, 376. — 89. M. Sieafried 




































7. ph. Ch. 46, 1905, 492. — 90. A. Baskof’: %. ph. Ch. 57, 10 390. 61, 19 
91. J. oho "PLA. 74, 1899, SIL. — 92. F i. 
86. — 99. G. Kosenfeld: Z. k. M. 28, 1895. 36, 1898, E. ne 1902, BOL. 





50. — 94. Dastre u. Floresco ) 10. Mutiires colorantes di foie w! 
Paris 1899, — 95. Nawnyn: Der Diabetes mellitus. 2. Antl. Wien 1906. C. 
Die Zockerkrankheit und ihre Behandlung. 6. Auf. Berlin 1912. Handbuch « 
Stoffweehsels. 2. Autl, Berlin 1907. 2, 1. — 9G. W. Schulze: A. m. A. 56, 19, 
O27. Ssobelow: V. A. 168, 1902, 91. — 98. A, Weichsethaum: SW. A. 119, 3. 
73. — 99. Herrheimor: V. A. 183, 1906, 238, D. m. W. 1906, 829. — 106 
10, internat. med. Kongr. 2u Berlin 1890, 2, Abt. 5. 97. De Henzi u. Reale: B. 
560. Vgl. O. Minkowski: B. k. W. 1892, 90. Untersuch. ther d, Diabetes mellit, 1, 
LEW, Pilager: oben unter 7. 8. 468. — 101. 0, Merings Vea. | 
Ne. k. M. 14, 1888, 405. 16, 1889, 43. 
131, “1910, 306. — 103, A. Evlandsen: B.%, 23, 1910 
* 104 4 Frank: ALP. P, 72, 1913, B87. — 105. L, Pollak: , 
— 106. E. Hirsch w. H. Reinbach: %. ph. Ch. 87, 1913, 128. — 10 
rf BP. 4, 1905, 1. — 108. 0. Jacobsen: B. d. ch. G. 6 1873, 1 
Bk. W. 1900, B66, 891. — 110. 11 Strauss: B.k. W. 1908, Nr. 12 
PA, 109, 1905, 807. — 112. Platners A. Oh. Ph. 51, 
‘A. Ch. Ph. 67, 1848, 1. 70, 1849, 149. — 114. 


















2 
= 











My ph. Ch. 11, 1 
1868, 2062. doh. G, 19, 1886, 369, 2000. 20, 1887, 685,"1988" Set ne 








115. B. Friedmann: BH. B. 8, 1903, 1, — 116. 


. Be i. 
117. J. Wohlgemuth Pagh tistics] 


Pettenkofer: 4. Oh. Ph, 


18, 1889, 248, — 

Ch. 45, 1905, 166. — oh 0, Minkowski wu. B.D y) A aH 
cS gear G. ‘Stddeler: A. Ch. Ph. 182, 1864, 323. — 123. IL Sters 

— 124. Brugsch w. Yoshimoto: Zo, Pou. 8, 1911, 639, .. 
H. Seopield: P. 3, 1889, 229. 7, 14, 1890, 173. — 126. L. Pax tar 
i 1888, 196. — 127. £. Cavazzoni: A. i. Be 57, 1913, 284. — WR. EP 
2 1889, 173. 12, J. A Charles: PA. 26, 1881, 201, — 180. 0. Hi 
Lehrbuch d. physiol. Chemic, 8, Auj, Wiesbaden 1914, ‘8.412. — 181. J. By 
90, 1902, 491. — 182. Be. Coyhlars, A. Fuchs ws 0.6. Firthe: B79 W 























ree) 
+7 
Wert 


7 


ET; FY led 
Pe ai 1 


r 
oo 
ry 

of 
fs 


i 


aa 

Bie 

a 
erst 


Pde 
Pe 
ie 
ape 
ole 
f-) 





‘erhardt> BP 
Centrathl. 1862, 
tonn 1897. — 
Ch. 50, 1906, 
Strashurger: 












27.) Literatur (§ 1 





BNF 

5 
s 
Z 


aus d. kais. Gesundheitsamte 1914. — 
77. — 230. Kxcherich: Die Darmbal 


Bg 
a 
= 
3 

Fee 
: 
= 
: 
‘ 
— 


ce 
Bis 
are 
Rent 
e 
i 


1, 1898, 5 


RS 
= 
Ss 

F 
+8 
ra 
FI 
ee 
& 
2 


= 
B 





ne 
PB 
bs 


§, 1801, 74. — 250. M. Borenstein: ¥ 
325. — 252. We. Moraczewski: %. 
‘Munk, Senator, Zuntz: V. A. 181, | 
f. 


FEES 
ay 
= 
i 
Ls 
i) 
> 
z 
a 
i 


260. J. Gi. Rey: A.V. P, 85, 1895, 205, 
"263. i. Gotitieh: 2. ph. Ob. 15, 4891, 
m, 


#5 


1896, 159. — 264. E. Abderhalde, 
158. — 266. F 
267. W. Biedermann: Die Aufnahme, Ve 
Wintersteins Handbuch d. vergleich. Physiologi 
P. 1906, 139. — 269, N. Zunte n. W. Ust 
Z. 4, 1907, 154. 





etal eta 


wae Ss wet a aesun pune marasamen mraico. 


tivem Druck kinnte durch die Zotten vermittelt werden. 1 
niimlich diese energisch zusammenzichen, so entleeren sie cent) 
Inhalt der Blut- und Lymphgeftibe. Namentlich die letateren w 
entleert bleiben, da der Chylus in den feinen Chylusgefiifen 
zahlreichen iglsppen am Zuriickstrémen verhindert wird. Geher 
die Zotten wi in den erschlafften Zustand tiber, so werde 
mit den filtrationsfihigen Flissigkeiten des Tractus vollsauger 
Nach Spee*® und Heidenhain*® sollen die Muskeln der Zotten di 


Lymphgefib aktiv erweitern. 
Uber den Einflub des Drackes auf die Griibe der Resorption \ 


IL. Diffusion und Osmose — ygl. § 15, 


Wenn xwol durch cine Membran voneinander gvtronnte Filssigkeite: 
Membran miteinander in Austausch troten, 0 hingt os yon dem Verhalten « 
ab, ob mar Diffusion oder nur Osmose oder beides cintritt. Ist dio Memb 
‘Lasnngamittel (Wasser) und den geliisten Stoff gleich gnt durchgdngig, so wird 
eintroten (als ob gar keine Membran vorhanden wire). Ist dagegen dio Memb 
das Lisungsmittel, nicht fir den geldsten Stoff durchgingig (semipermeabe! 
so wird nur cin Anstansch von Wasser (Osmose) eintreten. Tierische Mombran 
sich aber hiufig so, daB sie zwar sowohl fir Wasser, alt aueh fiir gewisse 5 
ig sind, ubor micht fir beides im gleichen MaBe (auch fur 
Stotfe in verschiedenom Grado); sie setzan dam Durchtritt der eldston 
grifleren Widerstand ontgegen ala dem des Wassers. Unter diesen Umstit 
Diffasion und Osmose nobenoinander her gehen kounen, — Kéth' stellty 
suche, in welchon die Resorption isotonischer Lisungen yon Harnstoff, Kochsalz 
‘aus der Bauchhéhlo von Kaninchen untersucht wurde, fost, da die hivrbel 
Kommonden Mombranen (PeritonoalEndothel, Wand der Bluteapillaren) am du 
sind ftir Harnstoff, weniger fiir Kochsalz, am wenigston fiir Zucker. 


Til. Es ist zurzeit noch nicht mdglich, alle bei der Resc 
Magen-Darmkanal beobachteten Vorgiinge auf Filtration oder Dif 
Osmose zurtickzufiihren. Es ist vielmehr nitig, anzunehmen, di 
Resorption eigenartige vitale Prozesse hauptsiichlich in dei 
zellen eine Rolle spielen, die wir zurzeit noch nicht nach e 
physikalischen Gesetzen erkliren kiinnen. 


So worden ans isotonischen Lisungen Kalinmsnlze schlochter resorbiert 
salxe, Auch aus hypotonischen Kochsalzkisungen wird noch NaCl resorbiart (vj 
—Hundoblutseram wird im Hundedarm ausgiebig resorbiert (Hi 
hier tindet also Resorption statt untor Verhaltnisson, wo xu boiden Soiton da: 
Membrun vollig gloichartig zusammengesetzte Flissigkeiten sich befinden. — 
‘man cinem wihrend dor Verdauung getiteten Kaninchen cin Stick Dinnday 
gpannt diese als Diaphragma in einem mit physiologischer Kochsulzisung gol 
aug, so wandert cine Zeitlang Flissigkeit von dar Schleimhautiliiche durch di 
nach der serisen Fliche (Zeid), — Werden die Darmepithelion goschildigt 
0,08 bis 0,3°/, NaF oder 0,006°/, Kaliumarseniat] oder entfernt, so entsprecher 
die Vorginge der Resorption den Gesotzon der Diffusion und Osmose (1 
Cohnheim®). 

Bei Rosorptionsversuchen am Oberlehenden Darm von Octepoden fand 
da Jodnatrium aus dem Darminnern vollatindig verschwand; ein Ubortritt 
Yo den Darm fand dabei nicht statt. 

For cine aktive Beteiligung des lebenden Protoplasmas dex Wpithels 
Resorption spricht auch die Tatsache, dal sogar Icichte Stdrungon in der 
Zellon, % B. nich Erkiltung oder Anfregung plitzlich erhebliche Abweichong 
tion, ja soxar Flissigkeitsabgabo in don Darm hinein zur Folge haben. 
Aiosy Weise xu erkliiren, dal die Gegenwart von verschiedener Gew™ 
die Resorption im Magen lebhaft vermehrt- 

vier?! find, dad dio Darmepithelion hungornder and Eek 
morphologische Untorschiody zeigem woraus ebenfalls went a” — We 
Zollen an der Veedannng tnd Rogorptio® goachlossen werden S80 qsstere® 


tic i orden 
es Darms zeigt bei Anregung der Resorptionstiitiskeit cime 


{§180) Resorption der EiwoiBatotte. 


sollten dies die ALbumosen und Peptone sein, die wegen ihrer | 
keit zum Durehtritt durch die Darmwand beftihigt erschienen. 

Nun sind aber wiihrend der Resorption einer eiweibreichen N 
Albumosen oder Peptone niemals im Blute nachweisbar. Brin, 
sie experimentell direkt in die Blutbahn, so wirken sie giftig: Sink 
Blutdruckes (junge Tiere kiénnen schon bei Gaben von 0,1—0,3 9 
pro Kilogramm Tier zugrunde gehen), Herabsetzung oder Aufhebun; 
rinnung des Blutes (vygl.S. 75); zugleich werden sie dureh 
ausgeschieden. Daraus folgt, dai bei der normalen Eiweifresorpt 
Albumosen und Peptone nicht als solche in die Blutbahn gy 
kinnen. 

Die Angaben tber den Nachweis von Albumosea im Blate werden von Abd: 
bestritten; dagegen fand Adderhalden, daB wihread der Verdanung Aminogit 
Blate in sehr geringer Menge vorhanden sind (vgl. 8. 81). 

Man hat friher angcnommen, daf die Peptone allerdings resorbiert wird 
vor ihrem Ubertritt in das Blut cine Rackverwandlung in Eiwei® erfubr 
meister™*, Heidenhain™, Glaessner™, Grossmann, Pringle u. Cramer). 

Es kann heutzutage kein Zweifel daran bestehen, da6 die Alb 
und Peptone nicht die zur Resorption bestimmten Endprodukte di 
dauung des Eiweif sind. Die Aufspaltung im Darmkanal schreitet v, 
tiber die Stufe der Peptone hinaus zu einfacheren Bausteinen des 
fort. Die Trypsinverdauung der Eiweibkérper (vgl. $114. 1) ms 
nicht bei der Bildang von Peptonen Halt, sondern flibrt bis zu 
spaltung des Eiweifi in die Aminosiiuren. In der Tat konnten K 
u. Scemann® im Dtinndarmehymus des Hundes Lenecin, Ty 
Lysin und Arginin nachweisen, dagegen keine nennenswerten | 
yon Albumosen und Peptonen; London’? fand auberdem auch noch : 
und Asparaginsiture, Abderhalden™ noch weitere Aminostiuren. 
Cohnherm™ im Darm entdeckte Erepsin (vgl. S$, 297) endlich 
nicht auf natives Eiweif, sondern nur auf die Albumosen und Pept 
und spaltet sie bis zu den einfachsten Spaltprodukten; nach Co 
wird das Kiweib im Darm durch die vereinigte Wirkung der Verds 
fermente vollstiindig in die einfachsten Spaltprodukte zerlegt, 
dureh kochende Schwefelsiiure. 

Andererseits hat sich zeigen lassen, dab Tiere mit weit abgeb 
Eiwei6 ausreichend erntihrt werden kinnen. Es gelang, Hunde 
Fiitterung mit Verdauungsprodukten des Eiweifi, die keine I 
reaktion mehr gaben (vgl. S. 269), im Stickstofigleichgewicht 
halten (Loewi?*, Henriques u. Hansen**, Liithje?*). Allerdings j 
negative Ausfall der Biuretreaktion noch kein Beweis dafiir, dab das 
auch wirklich vollstiindig bis zu den einzelnen Aminostiuren abgel 
(Abderhalden u. Prym*). Aber auch mit Verdauungsprodukten des 
die nachweislich nur noch aus Aminosiuren bestanden, gelang es, 
ausreichend zu ernihren, ja sogar Stickstoffansatz bei ihnen zu» 
(Abderhalden u. Mitarbeiter ??), Dasselbe ist beim Menschen bei Err 
mit abgebautem Kiweif vom Reetum her gelungen (Abderhalden, 
u. Schittenhelm*®). Man mu sich daher vorstellen, da in der 
Darm unter gewohnlichen Verhiiltnissen das Eiweif ganz oder ac 
grofien Teil bis zu den cinfachsten Spaltprodukten, den Armin 
abgebaut, dai also das Kiweif in Form yon AminosSurer 
biert wird, 

a nes Bicol 

Wird dem Gemisch von Aminosiiuren, da8 Arareh NW oor es Be 
Standen ist, cin Banstein (x. B, das Tryptophan) “Czogen, * © 


Landols-Rogomann, Physiologic, 14. Ang, 


Ey 


Ernihrende Kiistiere. Subentane Ernihrong, 
























veal) 


neathy Resorption anderer Stoffe. — Auch vie 
ice Stoffe kommen im Darmkanal zur Resorpti 
iS Chol schnell resorbiert, hauptsiichlich durch die B] 
F auch durch die Chylusgefiibe (Dogiel °), 
Pe A Farbstoffen wird Alizarin, Alkanna, Indigokarmin 
vin, Vt) wie Himatin; Chlorophyll wird nicht resorbiert, Zahlt 
in Ceneumlge Anfnahme (Blausiure nach wenigen Sekunden); ( 
hylns, 
Resorption ans den Geweben herans (nach parenchym 
). — Filissigkeiten, welche man in die Parenchyme einspr 
+ Hierbei heteiligen sich in erster Linie die Blutgefibe, d 
self elie, In letutere treten hierbei, von den Spalt- und Saftlticks 
nt, pine Kiirperchen hinein, z, B. Zinnober- und Tuschekornchen 
ing Blatkorperchen von Blotergiissen her, Fetttropfehen vom Marke 
Frege erden alle Lymphgefide eines Tiles unterbunden, so finde 
Bates fe schnell statt wie vorher; miissen die resorbierten F 
binge tie aufgenommen worden sein. Der entgegengesetste Versuch 
% iller Blutgefiibe keine Resorption der Parenchymfltissigkeit 
Ulop ,,*ite Mitbeteiligang der Lymphgeftife an der Aufsaugang, w 


tng “jetitentiBe natirlich auch die Lymphbildang in den, Geweber 
n't dod fe 


























Ty Qh Varabreichung per o%. Man bedient sich daher auch vielfi 

tiongm von goldsten Aransimitteln zu Heilzwecken. AuBer di 
wt die subeutane Injektion vor der Verabreichun 
dB manohe Mitel, welche cingenommen werden, 
auungsprozeB ao xersetzt werden, da sie gar nicht mnvi 





Ernihrende Klistiere. Subeutane E 


Menschen die Anfaahme der Nahrung durch den Mi 
rkeit des Oesophagns, hei anhaltendem Erbrechen 
Fon Corn. Celsus (3—5 n. Ohr.)) cine Ernihrang v 
Ledt die Resorptionstiihigkeit des Dickdarms der des 
‘Tatigkeit des Dickdarms fast gar nicht stattt! 
resorptionsfithige Sub: a. Man ii 
{- Jamgsam in den After cinlanfen; phinger 1 
‘acre surtckzuhalten. GroBere Mengen als 300 ene? 
sie lebhafte altik bewirken und schn 

die Flissigkeit mitunter 











nende 














1, Eiwei 
esorbi 


“bh Yi 
“Feectum allmiblich in Znoker ver 
5 rin wird von Reach" als besondors geeig 
Bre worden aur in solr geringor Menge reso 
FPankroas gomischt gegebon wenden. Auch Fl 
eewending kommen, (60 Punkreassubstana 7 
Aherang durch Klistiere bleibt jedoch stots 
‘dio Resorption des vierton Toiles dor xnvy 
NY (¥oit «. Baner®) and nur ines Diy 
ratorionmenge (Leube "). 
guhee eur Ergiiaxung cine subeutane & 
* Yeeds alloin wie Fette: 50—1009 lauw 
gaan in ca. 1 Stunde aus einem mit 4 


Far ant ficken. — Nach Henderson a 
Pedi dos injizierton Oles ausgenutat, 
Howe aubentanen Bindecowebe in dag 









ve 






















» 
Li 


Hit 


i 


TTY fo 
pr eance 
Feceeede 





154.) Krunkhafte ” 


ERedingungen. i fie 
eee uyzttem | 


geesetat, ‘und bei Morbaus 


chem erhiht ist (Maga 
‘FeGrperwmperatur vgl. anti 
Als Stoffwechsel 





oom Bodarf; in 


‘g> & = position cine Rolle: | 
== "FFeitencht (chenso gewi 
. Bedarf kann verwrsac 


n~ Perungszufuhr. — Di 
= die Quanti 


. 2 > erschub fiber den Bed 
es seaitz von Fett. Alerding 
Su == FRenommen, vo x. By 
lor fottreiche Nahi 


= == ound fir sich gering 
SE jabrelang Tag for Tag 
eS Be een onl. 

2. Durch einen ¢ 
© Se t igkeit: wonig Bew 
ea iehung des phiegmatisel 
WS S eclleicht spielt auch die E 
<> EeH wosentliche Rolle. — | 
SE ce Bbesform, toils wegen dor 
wr kt. — 0) Darnieder! 
<Roe Kastration, Fottsncht 
SH & istige Titigkeit: Fott 

Die Behandlung d 
e Nahrangss 
sce eed cinsoitize Bescbrinkun, 
exe 5glichst alle Fotte und Ke 

Ite schnelle Abmahme d 
BP esice. Dic Beschriinkung d 
SSteoile erstrecken und nicht 
ww Erd am choston das Ziel 
= rhaltung dos Kérpere 
b) den Vorbrauch 

item Heraen!) — 

er — ‘Trinkkuren usw. 





Unter den niedere) 

“KE © ile (Regeneration) 
PAerschneidung des Sibwa 
~~ Feuon xur Folge; ja es v 
F=seerr08 Weson hervor (Sp 
FSreinzngon. Avs jedem 
Sour einen Toil des Ran 
Ww iirts gerichteten Toile ei 
‘Saree, aus dom oberen Toile 
E2nden Kiipfo. — Auch bei 
Aeerschnittene Infusorien 
sstlicke war. — Quer zerse 
cweieder gu ganzen Individu