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Dorset-Street, Fleet- Street. 






















VOL. I. 
















T - _ — 




* - * 


Cambridge University Library, 
permanent deposit from 
Botany School 



Dorset Street, Fleet Street. 


The Translator feels that no other apology is necessary for 


introducing the present work to the British student of medicine 

than is afforded by the reputation of its Author as a physiologist, 
and the high character which the work has acquired, not only in 

Germany, but throughout Europe. Its translation was suggested 
to him by Dr. George Burrows, to whom he has on several occa- 
sions been indebted for advice always given with the greatest 

To render a faithful version of the original has been the Trans- 
lator's chief care; but at the same time he has found, that, to 
make it fitted to the wants of the student, something more was re- 
quired. In some instances the order in which the facts, and in- 
ductions from them, are stated, has been altered, that their con- 
nection might be easier of comprehension. In other cases it has 
been deemed advisable to omit from the text, and to place in the 
form of notes, discussions on subjects which, though interesting in 
themselves, did not appear to come within the limits of what is 
necessary or desirable in a text-book on Human physiology, parti- 
cularly when they formed a digression which tended to interfere 
with the course of the student's reading ; some few paragraphs 
have been entirely omitted, chiefly with the view of avoiding un- 
necessary repetition. To facilitate the labours of the student, like- 
wise, the paragraph where a new topic commences has been headed 
with a short statement of this in italics. Steel plates and wood- 
cuts, which, the Translator hopes, will be found useful, have also 
been added.* 

The additions made by the Translator consist almost entirely 
of newly-discovered facts, and are consequently, on account of the 

engraved under his direction. 




completeness of the original work at the time of its publication in 
1 835, few in number ; they are distinguished by being included in 


In reducing the numbers from the French to the EnglisMstand- 
ard of measurement, an English inch has been regarded as \ § of 



The Translator cannot too strongly express his grateful acknow- 
ledgements for the very kind and valuable assistance that he has 

Willis, and Mr. Q 


advice has mainly guided him in the execution of his task, and 

he has derived confidence from the consciousness of having such 

friends willing to aid him. 

He avails himself, also, with much pleasure, of this opportunity 
of acknowledging the many marks of kindness and friendship which 
he has experienced at the hands of Dr. P. M. Latham, and for 
which he must always retain a sense of gratitude. 

56, Devonshire Street. 



k * 


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Definition of Physiology 
1. Organic matter ; its elementary composition 

characters that distinguish it from inorganic matter 

its decomposition . . 

state in which the mineral substances exist in 

its simplest forms 

- its source, — its production by plants 

- equivocal generation 

2 . Of organism and life 

Organised bodies, — their distinguishing characters 
The organic force 
Vital stimuli 

• • 

• • 

— their mode of action 


distinguished from other stimuli 

not all equally necessary to the infant and adult 

* • 

its cause 

Decay and renovation of the organic material, — the cause 
Sources of the new matter, and renovation of the organic force 

3. Of the organism and life of animals 
Animals as distinguished from plants 
Functions of animals ; their classification 
Organic attraction 

• * 

• « 

• • 

Animal excitability, — its laws 

Exhaustion attended with material change 

EiFect of exercise 

Reaction, — its laws 

Stimuli, — their mode of action 

Medicinal agents, — their classification, and mode of action 

Brunonian theory 

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Theory of the contra-stimulists, — inflammation. 
4. The properties common to organic and inorganic bodies 

1 . Electricity ; 

its sources generally- 
electric fishes 

electric phenomena in frogs 
electricity in the human body 

2. Developement of heat 

in warm-blooded animals 
at different ages 





























Effects of external cold on warm-blooded animals, — hybernation 

of external heat 

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• • 

Developement of caloric in cold-blooded vertebrata 

in invertebrate animals 

Source of animal heat? 

• • 

in respiration . . 
in organic processes 
in nervous influence 

♦ • 

Cause of hybernation 

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« • 

3. Developement of light in animals 
Phosphorescence of the sea 
Luminous insects 

Developement of light in the higher animals 
Note on the temperature of insects . . 

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Of the circulating fluids, their motion, and the vascular system 


Of the blood. 

Its general properties 

Chapter i.— Microscopic and mechanical examination of the blood 
Of the red particles 

- their form 

- thei 

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r size 

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Chyle globules in the blood 

Action of water on the red particles 

Nuclei of the red particles 

Effect of different substances on the red particles 

Historical account of the red particles 

Of the liquor sanguinis 

I- Of the fibrin .. .. .. 

Its state in the blood 

Its proportion to the other ingredients 

1 in arterial and venous blood . . 

Coagulation of the blood in inflammation 
Cause of the buffy coat 

2. Of the serum 

• t 

t • 

its composition 

in different sexes, ages, and temperaments 











Chapter ii. — Chemical analysis of the blood 



1 . Of the red particles 

The nuclei,- — the red colouring matter 
State in which the iron exists in the blood 

2 . Of the fibrin .. 

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3. Of the serum 

4. The fatty matter of the blood 

Chapter hi. — Analysis of the blood by galvanism 
Dutrochet's hypothesis refuted 
No electric currents in the blood . . 
Bellingeri's experiments 

Chapter iv — Of the organic properties and relations of the blood 

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a. The vivifying influence of the blood 
Necessity for arterial blood § 


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b. Evidences of life in the blood itself . . 

Automatic movements of the red particles 
Motions in coagulating blood 

The organic fluids as well as the solids have life 

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c. Formation of the blood 
In the adult 

In the embryo , . I 

Influence of respiration on the formation of the blood 

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Of the circulation of the blood and the vascidar system. 


Chapter i. — Of the forms of the vascular system in the animal king- 


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Circular currents in the lower animals 
Vascular system in the avertebrate classes 
_ j n fishes . . 

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in reptiles 

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Metamorphosis of the circulating organs in the amphibia 
Aortic arches in the embryo of the higher vertebrata 

Various forms of the circulating system compared with reference to the 

greater and lesser circulation . . I 

Portal circulation 
Essential characters of the heart 

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Chapter ii. — Of the general phenomena of the circulation 
The heart's action, — its frequency 
Order of its contractions 

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Cause of the impulse 

Sounds of the heart,— their cause . . 


a. The lesser or pulmonary circulation 

Course of the blood through the right cavities of the heart 
Capillary network of the lungs 



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b. Greater or systemic circulation . . 
Course of the blood through the left cavities of the heart 
Circumstances that influence the motion of the blood in the arteries 
Anastomoses 5 — retia mirabilia 
Collateral circulation 
Capillary system of the body generally 

c. Portal circulation 

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Communications between the venous systems of the porta and cava 
Rate of the blood 9 s motion . . 

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Chapter in.— Of the heart considered as the cause of the circulation of 

the blood 

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Cause of its action 

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1. Influence of the respiration on the heart's action 

2. Influence of the nerves on the heart's action 

Nerves- of the heart, — experiments of Humboldt, Burdach, and others 
Influence of the brain and spinal cord on the heart 

Circulation in acephalous monsters . . 

Influence of the sympathetic nerve on the action of the heart 

Chapter iv. — Of the individual parts of the vascular system 





Of the arteries 

Their elasticity, —the pulse . . . . 

Arteries not muscular . . . . 

Vital contractility of arteries 

Force and rate of the blood's motion in the arteries 

Influence of respiration and of anastomoses on the motion of the blood in 

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the arteries 



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Of the capillaries 

1 . Structure of the capillaries 

Capillaries defined 

. their size 

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Form of the capillary network 

Vascularity of different parts 

Have the minute vessels open mouths ? — serous vessels ? 

Parts in which the existence of blood-vessels is doubtful 

Have the capillaries membranous parietes ? . . 

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2. Circulation in the capillaries . . • • .... 

As viewed by the microscope . . 

Degree of resistance offered to, and rate of the blood's motion in the capil 


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The heart's action the sole moving power 

The red particles themselves are passive, and are not arrested in the capil- 

Vital tumescence 

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Contractility of the capillaries 

Effects of the application of different substances to them 


Influence of the nerves on the capillary circulation 

Of the veins . . 

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vl . 




Auxiliaries of the venous circulation,— the valves,— the heart 
Influence of respiration on the venous circulation 
State of the vessels after death 

Chapter v.— Of the action of the blood-vessels in the processes of ab- 

sorption and exudation 

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a. Of absorption 

• • 

Proofs of absorption independent of the lymphatics and lacteals 
Experiments of Magendie, Emmert, Tiedemann, and others 

• • 

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Imbibition . . . . • • • » • • 


Time required for absorption by imbibition into the capillaries 

Mode of action of poisons 

Passage of ingesta into the secretions 

Matters absorbed must be in solution 

• • 

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The laws of endosmosis modified in the animal body 

Absorption by organic attraction . . 

Absorption aided by the action of the heart . • 

Influence of galvanism, of the nerves, and of plethora on imbibition 

Changes produced by the vessels on the matters absorbed 

Cutaneous absorption . . I 

Interstitial absorption 

b. Of exhalation and e xudation 

Exudation and exhalation from physical causes 
The process during life modified by organic law- 
Exudation of secretions . . . . 

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Of the lymph and the lymphatic vessels. 

Chapter i.— Of the lymph 

Physical and chemical properties of lymph 
Human lymph, — its microscopic characters 

Lymph of the frog 

Globules of the lymph and chyle . . 

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Chapter ii. — Of the mode of origin and structure of the lymphatic 


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Reticulated and cellular lymphatics . . 
Have the lacteals open mouths ? 
Structure of the intestinal villi 

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intestinal mucous membrane 

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The absorbent glands 

Structure of the absorbent vessels 

Communication of the absorbents with the secreting canals of glands 

Communication of the absorbents with small veins 

Terminations of the absorbents 

Lymphatic hearts 

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Chapter hi. Of the functions of the absorbents 

Source of the lymph 
1. Of the absorption by the lymphatics and lacteals 

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Proofs that these vessels absorb 

Peculiarities of the lymphatic and lacteal absorption 

Power by which they absorb 

2. Change effected by the lymphatic and lacteal vessels on their contents 

3. Motion of the lymph and chyle 
The moving power 
Rate of motion of the lymph and chyle 

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Of the chemical changes produced in the organic fi\ 

textures under the influence of the vital 

Purely chemical processes . . 

Organic chemical processes — assimilation 

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Of respiration. 

Chapter i. — Of respiration in general 
The atmosphere,— respirable and irrespirable gases 

Aquatic respiration 

The respiratory movements, — volume of air respired 

Necessity of respiration to different animals . . 

Chapter ii. — Of the respiratory apparatus 
Different forms of the respiratory apparatus . . 
In avertebrate animals . . . . 

In vertebrate animals . . . . 

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Chapter hi. — Of the respiration of man and animals 


1 . Of respiration in the air 

Changes produced in the air,— quantity of carbonic acid generated 

Amount of oxygen consumed 

Changes produced in the proportion of the nitrogen in the air by respira- 

• • 

• • 


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Respiration of cold-blooded animals 

Comparison of the products of the respiration of cold and warm-blooded 

• • 

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2. Of respiration in the water 
Changes produced in the water by the respiration of fishes 
Respiration of fishes by the skin,— in the air 

3. Of the respiration of the embryo of animals . . 
Respiration of the embryos of birds and insects 

• 9 

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of mammalia 


Blood of the foetus 

The liquor amnios . . 

Chapter iv.-Of the changes which the blood undergoes in the lungs 
Differences between arterial and venous blood. . 














v. n 



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« . 

• v 

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a. Experiments on arterial blood 

b. Experiments on venous blood 


Chapter v. — Of the chemical process of respiration 
Conditions on which the process depends 

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The different theories to explain the process 
Products of respiration in hydrogen and nitrogen 
Source of the carbonic acid evolved during respiration 

Chapter vi.— Of the respiratory movements and the respiratory 

a. The movements of respiration 
Movements of the thorax . . 

4 9 


of the larynx and fauces 

Contractility of the lungs and bronchi , . . . 

b. Of the influence of the nerves on the function of respiration 
Source of the nervous influence for the respiratory movements 

Sir C« Bell's views 

• • 

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Sympathetic affections of the respiratory muscles,— coughing, vomiting, &c. 

Cause of the respiratory movements 

Cause of the first respiration 

Effects of division of the vagus nerves 

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Of nutrition, growth, and reproduction. 

Chapter i.— Of nutrition 

a. Of the nutritive process 

* ~ - •• •• •• •• 

Nature of the process ; relation of the red particles of the blood to the process 
Source of the new material for the tissues 
Modification of nutrition by certain agents 

Nutrition dependent on the original creative power 
Renewal of material in the fluids of the body , . 
in the solids of the body.. 

b. Chemical composition of the organised tissues . . 

1. The brain, spinal marrow, and nerves 

2. Muscle 

3. The bones 

4. Cartilage 

5. The glands 

6. The different membranes 

c. Influence of the nerves on nutrition . , 

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Chapter ii — Of growth 

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a. Of the growth of organised parts by interstitial depositi 
Bone, — its structure 


its mode of growth . . 

Growth of muscles and nerves 

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b. Of the growth of unorganised non-vascular parts by the successive deposition 

of new layers 

• • 

1. Growth and structure of the horny tissues 
a. Epidermis and epithelium . . 

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36 L 









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b. Nails, claws, and hoofs 

c. Hairs • • » $ 

d. Horns . • 


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2. Growth and structure of the teeth 

3. of the crystalline lens 

c. Of the laws of growth and changes of form 
Limits to growth and change of form 
Law of developement from a uniform type 

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Chapter hi. — Of reproduction 

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Laws of reproduction , . . . 


Reproduction of polypes 

Production of double monsters 

Reproduction of planariae and annelides 
. in mollusca and articulata 

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in amphibia . . 

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Influence of the nerves on reproduction 
Reproduction of the tissues 
1. Reproduction unaccompanied by inflammation 

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of organised tissues 
of unorganised tissues 
The horny structures 
The teeth 
The crystalline lens 

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« ft 

2. Reproduction attended with inflammation 
a, with adhesive inflammation 

Formation of new vessels in fibrin 
Reunion of divided parts . . 

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• t 

of cartilage and fibrous tissues 
of bone, — callus 

of serous membranes, — skin . . 
of mucous membranes,— glands 

of nerves, — experiments thereon 

of brain and spinal cord 

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b. Reproduction with suppurative inflammation . . 
The process of granulation . . 
Reproduction of the skin by granulation 

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of bones after necrosis 

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Of secretion 


Chapter i. — Of the secretions in general. 

Distinction of secretions and excretions 

The secretions divided into two kinds « 

Secreting apparatus. — Secreting cells 

The cellular and adipose tissue . . . • 

The fat — Secreting membranes — Serous membranes 

The mucous membranes 

Mucus • . 

The skin. 

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its secretions 

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Chapter ii. — Of the internal structure of the glands. 
Former opinions regarding their structure 
Their simplest form a csecal tube or a follicle 
Compound glands formed of ramified cxecal canals 
The lachrymal gland 
The mammary — the salivary glands 
The pancreas 
The liver . ' 

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Glands formed of tubular, not ramified canals 

The kidneys 

The testes • . . . 

General results relative to the structure of glands 

Measurements of secreting canals, fyc. 

Chapter hi.— Of the process of secretion. 

1 . Of the causes of secretion 

General conditions of a secreting organ 

Seat of the secreting process, — mode in which the fluid is effused 

Why secretions differ from each other 

The process considered chemically . 

Microscopic globules of the secretions 

2. Of the influence of the nerves on secretion 

3. Of the changes of which secretions are susceptible 
Antagonism of the secretions 

4 . Of the discharge of the secretions 
Structure of the ducts,— their contractility 

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Of digestion, chylification, and the excretion of the decomposed effete 


Chapter i. — Of digestion in general. 

The food 

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Most simple nutritive substances, vegetable and animal 

Nutritive principle of food 

Azotised and unazotised aliments 

Necessitv of a varied diet • • I 

Dr. Front's classification of alimentary substances 

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Sensations connected with digestion, appetite and satiety, &c. 

Hunger and thirst 

Effects of long fasting 

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Chapter ii. — Of the digestive organs . 

a. Of the differ enb forms of the alimentary canal 

- r 

In the invertebrata 

In the vertebrata 

Influence of the nature of the food on the organisation 

b. Of the coats of the alimentary canal 
The mucous membranes, — its glands 

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The muscular coat, — the serous coat 

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Chapter hi.— Of the movements of the alimentary canal. 

How far subject to the will 

The sucking of new-born children 

1 . Deglutition, — its three stages 
Influence of the epiglottis in deglutition 

2. Movements of the cesophagus 
stomach during digestion 

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4. Ruminating J 

5. Vomiting 

Mode of action of emetics 

6. Motions of the intestines 

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Chapter iv. — Of the secretions poured into the digestive 
The saliva, — its chemical composition . . 


The gastric juice .. .. ... •• 

Its analysis . . . . 

The bile — biliary canals of insects . . 

Is the bile secreted from venous or from arterial blood ? 

* • * ^ 

Its properties and chemical composition 
Bile of serpents, fishes, &c— discharge of the bile 
The pancreatic juice, — its composition 
Secretion of the intestines . . 

Chapter v. — Of the changes which the food undergoes in the alimentary 

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• • 


a. Change effected by the saliva 

b . Change effected in the stomach — action of the gastric juice 
Dr. Beaumont's observations . . . . 

Table showing the time required for the digestion of different kinds of food 

Gas of the stomach . . 

Composition of the chyme 
Digestion in ruminants — in birds 
Theory of digestion,— theory of fermentation 
Theory of Schultz 
1 . Is there a gastric juice ? 

• • 

• • 

• • 



2. Is the gastric juice a solvent for food out of the body ? 
Experiments of Spallanzani, Tiedemann, and Gmelin, Dr. Beaumont and others 537 

3. Are the solvent principles in the gastric juice acids, or other unknown substances ? 540 
Experiments of Tiedemann and Gmelin, and Beaumont 



Researches of Eberle, Mueller, and Schwann 

• • 


« • 



Artificial digestive fluid 

Nature of the digestive process 

Chemical properties of the digestive principle or " pepsin 

• » 

Its action on casein • . . . • • • •••'.'• 

Suhstances not dissolved by the "pepsin" 
Influence of the nerves and of electricity on digestion 
e. Of the changes which the chyme undergoes in the small intestine 
Influence of the bile on the chyme 
Effects of ligature of the bile duct 

• • 

d. Changes which the ingesta undergo in the large intestine 

ft • 

Gaseous matters in the intestines 
The faeces . . • • 

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XV 11 






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Chapter vi.— Of chylification. 
Absorption of the chyle 
Properties of the chyle 

Differences in the chyle, arising from variety of food 
The chyle globules,— cause of the white colour of the chyle 

Its red colour • • 
The fibrin of the chyle,— its source 
The serum, — its composition 
Comparison of the chyle with lymph, 

Effect of ligature of the thoracic duct 

Chapter vii.— Of the function of the spleen, the supra-renal capsules, the 
thyroid, and the thymus glands. 

-with blood 

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• • 

• # 

a. The spleen,— its structure 
Function of the spleen 

b. The supra-renal capsules,— their structure 
Function of the supra-renal capsules 

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c. The thyroid body, 

d. The thymus gland, 

its structure 
■its structure 

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• • 

Function of the thymus . . 

; CHA p TEU viii— Of the elimination of the effete decomposed matters 
Cause of excretion,-relative quantity of the excretions 
Excretion of foreign matters . . 

1. Cutaneous exhalation and perspiration 
' Their quantity under different circumstances 

• • 

• • 

Their composition 

Object of the cutaneous secretion 
2. The secretion of urine 
' Properties of the urine 
a. Essential constituents of the urine 

1. Urea •• 

its composition, — its artificial production 

- present in the blood 

its source • • 

The urine in diabetes and dropsy 

2. Uric acid,— its composition 

In the urine,— its red colour 

Relation of uric acid to urea 
Urine of different animals 

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Urine in diseases, — source of the uric acid . . 

3. Hippuric acid, its properties and composition 

4. Lactic acid . • . . . . • « 

5. Salts of the urine 
Proportion of solid matter of urine under different circumstances 

b. Accidental constituents of the urine 


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» • 

Matters which are not excreted with the urine 



excreted with the urine, but in an altered state 

• • 

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Office of the renal excretion 

Action of alkaline carbonates, and the salts of vegetable acids on the urine 

Time which elapses before ingesta reach the urine . . 

Discharge of the urine ♦ . . . . • 








Physiology of the nerves* 


Of the properties of the nerves generally \ 

Chapter I. — Of the structure of the nerves. 

a . Of the principal forms of the nervous system 

Type of the radiata 


• • 


• 4 

• • 

• • 

1 & L 

b. Of the minute structure of the nervous substance 


Primitive fibres of the nerves . . . • 

Primitive fibres of the brain 

Grey fasciculi in the nerves . . 

Course and arrangement of the nervous fibres 

Mode of termination of the nervous fibres 

Grey substance of the brain and spinal cord, and ganglia 

Ganglia, — their classification • . . . • . 

Chatter ii. — Of the excitability of the nerves 

1. Action of stimuli on the nerves 

mechanical stimuli 

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chemical stimuli 
electric stimuli 

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2. Of the changes produced in the excitability of the nerves by stimuli 

1. Renovating stimuli . . 


2, Alterant stimuli . . . . . . 

Mode of action of narcotic poisons 

Dependence of the nerves on the brain and spinal cord 

Chapter hi. — Of the active principle of the nerves 
Comparison with electricity 
Do electric currents exist in the nerves ? . . 






Of the nerves of sensation, the nerves of motion, and the organic nerves, 

Chapter i. — Of the sensitive and motor roots of the spinal nerves 
Experiments demonstrating their properties . . 

t • 

Chapter ii. — Of the sensitive and motor properties of cerebral nerves 
The fifth pair 

• • 

• t 

• * 

• • 

• • 

» • 

• • 

The glossopharyngeal . . 

The vagus and spinal accessory 

The ninth pair . . 

The third, fourth, and sixth nerves 

The facial nerve 

Chapter hi. — Of the sensitive and motor properties of the gangl 
or sympathetic nerve . . . . . . . 

Sensitive properties of the sympathetic 
Motor properties of the sympathetic 


Composition of the sympathetic . . 

• • 

• * 

• • 


Chapter iv.— Of the system of grey or organic fibres, and its properties 

1 . Grey fibres in cerebrospinal nerves 

2. Grey fibres in the ganglionic or sympathetic nerves 

3. Functions of the grey or organic fibres .. .. .. 

Chapter v. — Of motor, sensitive, and organic nerves in the nervous 

system of invertebrata. 

• • 

• • 

• • 













, i * 



Of the mode of propagation of nervous action in different nerves. 

Theories of nervous action 
Rate of nervous action 
M. Nicolai's observations 

i ' 

• • 

• • 

• • 

» • 

• • 

Chapter i. — Of the laws of action of motor nerves 

a. Of the lavjs of the transmission of nervous influence in motor nerves 

b. Of the associate or consensual movements 

Motions of the iris 

Theory of the consensual movements 

• • 

• t 

• • 






• • 

• • 

• • 

• • 

• • 

Chapter ii.— Of the laws of action of sensitive nerves 

a. Of the laws of transmission of nervous influence in sensitive nerves 
Theory of sensation 

The sensations referred to amputated limbs 
Transposition of sensations 

b. Of the radiation of sensations . . 

c. Of the coincidence of sensations . . . 

Distinctness of sensations in different parts 
Single vision with the two eyes 

Chapter hi. — Of the reflected motions 
Different explanations of them 
Dependent on the spinal cord . . 

State of irritability of spinal cord, — how produced 

1 . Local reflected motions 

2. Reflected motions of systems of muscles 

3. Reflected motions of muscles of entire trunk from irritation of 

# • 

• • 

• • 

• • 

• • 

• • 

• • 

• • 

• • 

• • 



• • 

• • 


Dr. Hall's observations 

from irritation of nerves 

• • • • 

The reflected motions attended with sensations, though not necessarily 

Paths of transmission of the influence from the sensitive to the motor 


• • 

• • 

• • 

Theory of the reflected motions 

Chapter iv.— Cause of the different action of the sensitive and motor 


• • 

• • 

• • 

• • 

• • 


Chapter v. — Of the laws of action of the sympathetic 
Of the actions of the sympathetic in involuntary motions 
Reflex actions of the sympathetic 
Influence of the ganglia 

b. Of the sensitive functions of the sympathetic 
Influence of the ganglia , . . . 

• • 

• • 

• • 

• • 

• • 

• • 

• * 

# • 

• • 

c. Of the organic functions of the sympathetic 
Influence of the ganglia 

Chapter vi — Of the sympathies 
I. Sympathies of the different parts of a tissue 
II. Sympathies between different tissues 

III. Sympathies of individual tissues with entire organs 

IV. Sympathies between different organs 
V. Sympathies of the nerves . . 

• • 

• • 

« • 

• • 

• • 

♦ • 













• • 















Of the peculiar properties of individual nerves. 

Chapter i. — Of the nerves of special sense 

• • 

• • 

Nature of sensation . . . . . . . . . . 

The nerves of the different senses cannot perform the functions of each other 


The fifth the nerve of taste . . 

Influence of the fifth on the other senses 


Chapter ii. — Of the peculiar properties of other nerves 

• * 

• • 


Of the motor nerves of the eye and iris I 

Movements of the iris dependant on the third nerve 

Comparative anatomy of the motor nerves of the eye and of the lenticular 

Of the fifth nerve . . 

Its communications with the sympathetic 

• • 

• ♦ 

• • 

- with the lenticular ganglion 

- with the spheno -palatine ganglion 

• ♦ 

• • 

• • 

• • 

• with the otic ganglion 

Comparative anatomy of the fifth nerve 
Of the facial neuve 

Its comparative anatomy . . . . . . 

Connection of the facial with the gustatory — the chorda tympani 

Of the glossopharyngeal nerve 

Its comparative anatomy 

Of the vagus 

Its comparative anatomy 

Of the spinal accessory 

Of the ninth pair 

Its comparative anatomy I 

Arrangement of the cerebral nerves into primitive and derivative 
Of the sympathetic nerve . . . . .... 

Its peculiarities in different animals . . . . • . 

• • 

♦ • 

• • 

• • 

• • 

• ♦ 

9 • 

• • 

* * 

• » 















78 L 



Of the central organs of the nervous system 

• • 

• • 

• • 

• • 

• ♦ 

Chapter i.— The central organs of the nervous system considered 



Functions of the nervous centres 

Formation of the nervous centres 

Functions of the nervous centres in the lower animals 

Relative size of the nervous centres in different vertebrata 

Chapter ii. — Of the spinal cord 
Its structure 

1. The spinal Cord a conductor of nervous action 
Mode of origin of the spinal nerves 
Relation of the spinal cord to the nerves . , 

* • 

» • 

• * ' 

• • 












• • 




« * 

• • 

Properties of the anterior and posterior columns of the cord 
Properties of the white and grey substances of the cord 
Resemblances between the spinal cord and nerves 
2. The spinal cord as a part of the central organs of the nervous system 
The spinal cord a reflector of centripetal impressions upon motor nerves 

• • 

• • 

• • 

• • 

• • 

does not perceive sensations 

a source of motor power 

propagates any change in its state very readily 

is the source of the force of our movements 

is the source of the sexual power 

has an influence over organic processes 

• • 

• « 

• • 

9 ft 

• * 

• ft 

• • 

ft • 

Chapter hi. — Of the brain . . 

1 . Comparative anatomy of the brain 

2. Of the powers of the brain and the mental functions generally 
Relative size of the brain in different animals and man 
The brain, and no other organ, the organ of the mind 
Influence of the passions on the different viscera 
The mental principle not confined to the brain 
Latent state of the mind in the generative fluids and germ 
In idiotcy and insanity, &c. the brain only, not the mind, affected 
Is the mind identical with the vital principle ? 

The doctrine of materialism 

Source of the multiplication of the mental principle in generation 

3. The medulla oblongata . . . . . . 

• • 

• t 

• • 

• • 

• • 

Its structure 
Its functions 

• • 

* • 

• • 

• • 

* • 

4. The corpora quadrigemina 
Their functions 

5. The cerebellum 
Its functions 

• • 

• • 

• • 

Its relation to the sexual instinct 
6 . The cerebral hemispheres 

• • 

• » 

• • 

• • 

• • 

# # 

• • 

* • 

• • 

• • 

Their functions I 

Gall's doctrine of cranioscopy or phrenology 
7. Propagation of nervous action in the brain and spinal cord 
Sources of paralytic affections and of convulsions 

Parts which influence the opposite and those which influence the same side 
of the body 

• • 

• • 

• • 

• » 

• •) 

• • 













Varieties of paralysis and convulsions 
A. 1. Paralysis from lesion of the spinal cord 

• • 

• • 

• • 

• • 

• • 


the brain 

B. 1 . Convulsions from affections of nerves 

• • 

• • 


of the spinal cord 
of the brain 

• • 

# • 

ft • 

• • 

Rotatory motions of animals from lesions of certain parts of the brain 
Rotatory sensations — Vertigo — Purkinje's experiments 

• • 










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fFig. 1 to 6 represent the particles from the blood of different animals, all magnified 

about four hundred diameters. 


Fig*. 2. Red particles of the blood of the common fowl, a, Ordinary appearance 
when the flat surface is turned towards the eye ; 6, appearance which is sometimes 
presented by the particle when in the same position, and which suggests the idea of a 
furrow surrounding the central nucleus ; c, d 7 different appearances of the particles 

when seen edgeways. 

Fi&. 3. Red particle of the frog. 

of the squalus squatina, after Wagner. 

Fig. 4. 

of the lophius piscatorius, after Wagner. 

#, One 

Fig. 5. 

Fi£. 6. Particles from the blood of the scorpion, also copied from the figure given by 

Wagner, who has erroneously asserted (as cited at page 109) that the particles of the 
blood of all invertebrate animals are roundish, while in the larvae of several insects — 
the dytiscus, libellula, and ephemera, for example— the particles circulating in them 
can be distinctly seen to be much elongated and flattened. In other transparent larvae 
in which the action of the heart and its valves are very easily distinguished, no par- 
ticles are visible. 

Fig. 7- Lymphatics of the glans penis and prepuce, after Breschet. a, Superficial 
layer of lymphatics on the glans ; 6, the same on the prepuce ; c, deep layer on the 
glans ; d 7 large lymphatics surrounding the base of the glans. (See page 264.) 

Fig. 8. Lymphatics of the mucous membrane of the stomach, after Breschet. a, 
Superficial layer • 6, deep layer. 

Fig. 9. One of the intestinal villi, with the commencement of a lacteal after Krause. 
(See page 269.) 

Fig. 10. Lamina of the cartilage of bone cut from a transverse section of a cylindrical 
bone of the human subject, as viewed with the microscope, copied from Miescher's 
figure. #> One of the canals of Havers surrounded with concentric lamellae ; 5, com- 
munication between two of the canals ; c, lamellae that form larger circles around the 
medullary cavity. (See page 378.) 

Fig. 11 • A longitudinal section of the cartilage of bone, after Miescher. 
of the canals of Havers cut longitudinally ; 6, a similar canal more deeply seated in the 
lamina of cartilage. 

Fio\ 12. A transverse section of one of the canals of Havers, with its concentric 
lamellae more highly magnified, (about three hundred times,) showing the radiated ap- 
pearance produced by the short lines that partly traverse the substance of each lamella. 

Fig. 13. Osseous corpuscules, very much magnified, with the ramifying lines that 
issue from them, after Miiller, in a paper appended to Miescher's dissertation, De in- 
flam. oss. eorumque anat. (See page 379.) 

Fig. 14. Thin lamina from the ossifying epiphysis of the humerus of a foetal calf, 
taken from a section made perpendicularly to the ossifying surface, as shown in the 
outline sketch of the bone, and highly magnified, a, Uniform granular cartilage ; 6, 
cartilage nearer to the ossifying surface, the corpuscules aggregated into cells or 
columns ; 0, bone shooting into the cartilage. 

Fig. 15. Thin lamina from a transverse or slightly oblique section of the ossifying 
surface. (See the figure of the bone.) a, Cartilage with the corpuscules in groups ; 6, 
the bone enclosing cells or tubes. This and the preceding figure are copied from draw- 
ings lent to the Translator by Dr. Sharpey. (See page 382.) 

Fig. 16 represents the appearance in thin laminae of the cartilage of the epiphysis 
taken from near the ossifying surface, and magnified, but less highly than the two 
preceding figures, a, a, Sections of the canals in which blood-vessels run ; 5, commu- 
nication between two of these canals ; the corpuscules are seen to be collected into 
groups which are arranged in a radiated manner around the canals. (See page 383.) ] 




Page 110, in the note, for " Dr. Gordon, also, in his Syllabus of Lectures on Ana- 
tomy," read, " Dr. Gordon, also, in his Outlines of Lectures on Human Physiology, 
published in 1817, page GG." (The paragraph in Dr. Gordon's Outlines referred to in 
the note is the following : Venous blood " is discovered by the microscope to consist 
of two parts ; a transparent fluid, and red particles, a, The transparent fluid begins 
to suffer a species of decomposition called coagulation the moment it escapes from the 
veins of the living body, and therefore cannot be examined in its natural state. Its 
properties judged of by an examination of the products of this decomposition. These 

products are serum and fibrin.") 

Page 160. Fig. 5. The vessels distinguished by the cypher 8 are veins which 
return the blood from the muscles of the back, and pour it into the afferent renal 

vein (9). 

Page 252. Heading of page ; for " Absorption of the skin," read "Absorption by 

the skin." 



Page 87, line 4, for « Dr. Marshall Hall," read « Dr. E. Hale ' ' 
age 212 the paragraph at line 28, « This can be seen distinctly in the water sala- 
mander, to precede, instead of following, the paragraph, « At the extremity of 
each of the villi," & c . at line 26. ' 

Pro S* r UeS I* ^ 16,f ° r " N ° Va Sc ° tia '" W " New C ^onia." 

PaL S9fi' r ! 7, /° r " animalS ai * e beSt aWe '" read "animals are least able." 
*-age 526, line 3, for « goat," read " horse." 





Physiology is the science which treats of the properties of organic 
bodies, animal and vegetable, of the phenomena they present, and of 
the laws which govern their actions. Inorganic substances are the ob- 
jects of other sciences, — physics and chemistry. 

In entering upon the study of physiology, the first point to be ascer- 
tained regards the distinctions between these two great classes of 
bodies — the organic and the inorganic, — and the following questions 
suggest themselves for discussion. Do organic and inorganic sub- 
stances differ in their material composition ? and since the phenomena 
presented by these two classes are obviously so different, are the forces 
or principles on which they depend, also different; or are the forces 
which give rise to the phenomena of the organic kingdom merely 
modifications of those which produce physical and chemical actions ? 

1 . Of Organic Matter. 

Nothing analogous to sensation, nutrition, or generation, is presented 
by inorganic bodies, and nevertheless the matter which composes or- 
ganic bodies consists of precisely the same elements as inorganic matter. 
In examining the composition of organised bodies, it is true, we meet 
with substances — the proximate principles, or principes immediats— which 


are peculiar to organic bodies, and cannot be produced artificially by any 
chemical process ; such are fibrin, albumen, gelatin, &c. But all these 
substances may be reduced by chemical analysis to the same simple 
elements which constitute minerals. Of these simple substances, all en- 
tering into the composition of inorganic bodies, there are fifty-two. In 
organic bodies there have been discovered but eighteen. 

The elementary substances which are met with in plants are : 






4. Nitrogen, 

5. Phosphorus, 

6. Sulphur, 

7. Potassium, 

8. Sodium, 

their most essential components. 

found less frequently. 

, principally in vegetable albumen and gums, especially 
in the tetradynamia, combined with nitrogen. 

. almost universally. 

. principally in marine plants. 





found almost universally 
. rarely. 

9. Calcium, 

10. Aluminium, I 

11. Silicium. 

12. Magnesium, occurring rarely > 

13. Iron, 

14. Manganese, 

15. Chlorine. 

16. Iodine, 

17. Bromine, 

. frequently. 

in marine plants 

The same substances, with the exception of aluminium, are met with 
likewise in the animal kingdom. Here sodium is more frequent, the 
potassium less frequent than in plants; iodine and bromine occur in 

some marine animals. 

In man and the higher animals the components are : 





























met with principally in the hair, albumen, and brain, 

in the bones, teeth, and brain. 

in the teeth and bones. 

15. Iron, 


found in the hair. 
# . in the blood, pigmentum nigrum, and crystalline lens. 

r is also numbered among the substances which sometimes 
enter into the composition of organic bodies. Beecher asserts that he 



tutes, then, the first difference between organic and inorganic bodies. 
All the elementary substances found in the inorganic kingdom do not 
enter into the composition of organic bodies ; some are even inimical to 

their life. 

The mode in which the elements are combined forms a second dis- 
tinguishing character ; and the peculiarity of organic matter depends 
probably on the following circumstances, first pointed out by Berzelius 

and Fourcroy. 

1. In mineral substances the elements are always combined in a 


binary manner; thus, two elementary substances unite together, and 
this binary compound unites again with another simple substance, or 
with another binary compound. For example, carbonate of ammonia is 


* Tiedemann's Physiology, translated, with notes, by Drs. James Manby Gulley, 


and J. Hunter Lane, p. 6. 











constituted of carbon, oxygen, hydrogen, and nitrogen, combined as fol- 

lows : 


unite to form carbonic acid, 


which again unite to form carbonate 
of ammonia. 




Nitrogen, ^^^^^^^^^^ ^^^^^^^^^^^^^ 

In minerals the elementary substances are never observed to combine 
three or four together, so as to form a compound in which each element 
is equally united with all the others. This, however, is universally the 
case in organic bodies. Oxygen, hydrogen, carbon, and nitrogen, the 
same elements which by binary combination formed inorganic substances, 
unite together, each with all the others, and form the peculiar proxi- 
mate principles of organic beings. These compounds are termed ternary, 
or quaternary, according to the number of elements composing them. 
Vegetable mucus, starch, and adipose matter are ternary compounds of 
oxygen, carbon, and hydrogen : gum, albumen, fibrin, animal mucus, and 
resin are quaternary compounds, their fourth ingredient being nitrogen. 

A doubt has recently been thrown upon this theory of the composi- 
tion of organic substances, especially with respect to some particular 
products, such as alcohol; but there is still great probability in its 
favour, and more particularly in reference to the higher organic com- 
pounds, such as albumen, fibrin, &c.~* 

It must at any rate be admitted, that the mode in which the ultimate 
elements are combined in organic bodies, as well as the energies by 
which the combination is effected, are very peculiar ; for, although they 
may be by analysis reduced to their ultimate elements, they cannot be 
regenerated by any chemical process. 

* Berard Proust, Dobereiner, and Hatchett believe that they have succeeded in 
producing organic compounds by artificial processes ; but their results have not been 

sufficiently confirmed. 

of the artificial formation of these substances, 
solution of ammonia, after being saturated with cyanogen, contained a considerable 
quantity of oxalic acid. Again, in the preparation of potassium from charcoal and 
carbonate of potash, a black mass passes over with the metal, which, when treated with 
water, yields a large proportion of oxalic acid. Oxalic acid, however, is now regarded 
as a binary compound of carbon and oxygen ; the fact that it undergoes decomposition 
when its water of crystallization is extracted, is no proof to the contrary, for nitric acid 
also is decomposed by the extraction of the last portion of its water. See Mitscherhch's 
Chemie, p. 416. Woehler also finds, that urea is obtained in place of cyanite of 
ammonia, when a solution of chloride of ammonia is poured over freshly precipitated 
cyanite of silver, chloride of silver being formed at the same time. Urea is also form- 
ed in the decomposition of cyanite of lead by solution of ammonia. The solution at 
first contains cyanite of ammonia ; but, by evaporation of the fluid, this salt is convert- 
ed into urea. la the same way, also, when cyanous acid is mixed with water or 
liquid ammonia, cyanite of ammonia is first formed, and thence urea. — Gmelin's 
Chemie, vol. iii. p. 6 ; Berzelius, Thierchemie, p. 356. Urea, however, can be 
scarcely considered as organic matter, being rather an excretion than a component of 
the animal bodv. It has not perhaps the characteristic properties of organic products. 

B 2 






2. Another essential distinction pointed out by Berzelius is, that in 
organic products the combining proportions of their elements do not ob- 
serve a simple arithmetical ratio. Thus, for example, there is a large 
number of different kinds of fatty matters which Chevreul has examined, 
and many of which, according to his experiments, differ only by frac- 
tional parts in the numerical proportions of their atoms. 


3. Organic bodies consist chiefly of combustible matter, which, both in 
animals and vegetables, is constituted (the acids excepted) of carbon 


and hydrogen, combined with oxygen in quantity not sufficient to 
saturate the other elements.* 

Tendency to decomposition. — The matter forming organic bodies has a 
constant tendency to undergo decomposition ; it is only the continuance 
of life which preserves it. But even during life the balance, which 
maintains its elements in their peculiar combination, may be destroyed 
by the agency of certain simple inorganic bodies, or binary compounds 
of these, as we witness in the burning of parts of the living body. At 
some period or other this change necessarily ensues spontaneously in 
every living being ; the state or influence which maintains the elements 
in their peculiar combinations becomes more and more feeble, and is, at 


length, no longer able to counteract the tendency of these elements to 
form binary compounds among themselves, and with other simple sub- 
stances in the atmosphere around them. Organic matter is thus anni- 
hilated, and with it the organised being of which it formed part. 
And in ceasing to present the phenomena of life, it falls under the 
influence of the laws which govern the formation of chemical com- 
pounds, presenting the phenomena of fermentation and putrefaction, a 
foul smell being produced when the substance contained much nitrogen. 
Chemical compounds, we know, are regulated by the intrinsic properties 
and the elective affinity of the substances uniting to form them ; in 
organic bodies, on the contrary, the power which induces and maintains 
the combination of their elements does not consist in the intrinsic pro- 
perties of these elements, but is something else, which not only coun- 
teracts these affinities, but effects combinations in direct opposition to 
them, and conformably to the laws of its own operation. Light, heat, 
and electricity, it is true, influence the compositions and decompositions 
going on in organic bodies, as they do those in inorganic bodies ; but 
nothing justifies us in regarding without further inquiry any one of the 
imponderables, — namely, heat, light, and electricity, — as the final cause of 
vital actions. 

After the cessation of life, organic substances always undergo decom- 
position, if the conditions necessary for the exertion of chemical affinity 


* These distinctive characters of organic matter will be found more fully detailed in 
the classical text-books, of chemistry by Berzelius and Gmelin, and of anatomy by 
Weber in his fourth edition of Hildehranrlt.'s Anatomie des Menschen, vol. i. 









are present. The products' of this decomposition are nitrogen and hydro- 
gen, (which partly escape in a free state,) water, carbonic acid, carburet- 
ted hydrogen, olefiant gas, ammonia, cyanogen, prussic acid, phosphuret- 
ted hydrogen, and hydrosulphuric acid ; while in some cases the elements 
reunite in different proportions so as to form a new organic compound, as 
in the production of sugar from starch in the saccharine fermentation. 
Sometimes from one organic substance two new compounds are gene- 
rated, — one organic, the other inorganic., — as in vinous fermentation, 
during which carbonic acid and alcohol are formed from sugar. Decom- 
position does not commence in the bodies of animals and plants immedi- 
ately after their death. This Gmelin explains by supposing that the 
conditions necessary for the exertion of elective affinity are not then 
present, just as several inorganic substances require a certain tempera- 
ture for their decomposition.* 

The conditions more or less necessary for the spontaneous decomposition 
of organic matter, are moisture, the access of atmospheric air, and a cer- 
tain temperature. The first is absolutely necessary ; organic substances 
when perfectly dry do not undergo decomposition at the ordinary tem- 
perature of the atmosphere. Air is also often necessary, but not 
always; moist animal tissues suffer decomposition even when atmo- 
spheric air is excluded, although the presence of air facilitates putre- 
faction in the highest degree, even more than oxygen. A certain tern- 
perature is always necessary. 

The gaseous products of the decomposition of animal matter, and of 
the human body in particular, are carbonic acid, sometimes nitrogen, 
hydrogen, sulphuretted hydrogen, phosphuretted hydrogen, and ammonia. 
Acetic acid is also formed, and sometimes nitric acid. The solid matter 
that remains, consists of the carbonaceous matters, which decompose 
more slowly, and the fixed mineral ingredients, earths, oxides, and salts, 
which with the carbonaceous matters form the soil (humus).f Several 
parts of the bodies of man and animals immersed in water, or buried 
in certain situations, even without the access of water, undergo a 
peculiar change, being converted into a substance, named adipocire. 
Berzelius is of opinion, that the fibrin, albumen, and colouring matter of 
the blood, as well as the adipose matter, may be converted into this sub- 
stance ; while Gay Lussac and Chevreul state that the fat, which can 
be extracted from fresh animal textures by chemical processes, equals 
in quantity the adipocire generated by putrefaction in water, and infer, 
therefore, that the fat merely is converted into adipocire, while the 
other tissues are destroyed. 

State in which mineral components exist in organic bodies. — The pro- 
portions in which the oxygen, hydrogen, carbon, and nitrogen are com- 
bined seem to constitute the chief differences in the composition of 

* Gmelin 's Chemie, vol, iii. p. 9. 

-f See Weber loc. cit. vol. i. p. yO. 




organic substances. The organic compounds of these elements especi- 
ally, are ternary and quaternary, not binary. In what state the less 
abundant mineral ingredients exist in organic bodies, — whether they like- 
wise enter into the formation of ternary or quaternary compounds, or 
are merely mingled with them in the binary form, — is an important ques- 
tion which cannot at present be determined. Engelhardt has ascer- 
tained that the mineral ingredients can be separated from a watery so- 
lution of the colouring matter of the blood, and other animal matters, by 
means of chlorine. From this fact, and from the iron not being extract- 
ed by acids, Berzelius infers it to be probable that the iron in the 
blood is in the metallic state, not in that of oxide ; for chlorine has a 
very strong affinity for metals, and not for oxides, for which acids on 
the other hand have a great affinity. Professor Henry Rose adduced 
some experiments which seemed to show that the iron was combined as 
an oxide with the animal matter, thus as an albuminate of the oxide ; 
but Berzelius again rejects this idea, for in that case the oxide ought 
to be extracted by acids from the blood as it is from artificially formed 

albuminate of iron.* 

Berzelius cannot decide in what form sulphur and phosphorus exist 
in animals ; whether united with other simple substances to multiple 
organic compounds, or combined with the ternary compounds of other 
simple substances so as to form secondary binary compounds, or 
whether each of these substances, already in a binary form, is again 
combined with other substances. Vauquelin, by burning the fatty mat- 
ter of the brain, obtained a cindery mass, which contained so much 
phosphoric acid, that this latter substance by preventing the access of 
air arrested the combustion ; on removing the phosphoric acid by means 
of water, the mass again burned for a time, until more acid was form- 


ed upon the surface. From this circumstance we see, says Berzelius., f 
that this cinder contains phosphorus in a fixed, not volatile state, — in a 
state hitherto unknown in inorganic nature. 

Many circumstances, however, render it probable that several 
mineral substances in the binary form, as salts or oxides, exist in the 
animal body, either mixed or chemically combined with the animal 
matter. These circumstances are : 1. the appearance of minute micro- 
scopic crystals in the animal fluids simply evaporated; 2. the facility 
with which the mineral substances contained in plants vary with their 
situation, which could not be the case if the mineral elements existed 
in them merely as elements of the organic compounds ; 3. the facility 
with which salts, which enter the blood accidentally, are separated from 


* [The arguments of Rose, Engelhardt, and Berzelius, on this point, are stated 
fully in the section on the Chemical analysis of the blood ; the translator, therefore, 
considered it unnecessary to give them here at length.] 

-J- Thierchemie, p. 16. 



■ , 

1 I » c * - * 




it in the urine ; 4. that chloride of sodium can, as Autenrieth remarks, 
be separated from solid animal matter by mere washing ; 5. the state 

of the phosphate of lime in the bones. 

Professor E. H. Weber 

shows clearly, that the phosphate of lime of the bones does not exist in 
them as phosphorus, oxygen, and calcium ; but that it is in the state of a 
salt combined— perhaps only mechanically mixed— with the cartilagin- 
ous substance, since madder (rubia tinctorum), which has a strong affi- 
nity for phosphate of lime, but none for lime or calcium, is attracted, 
during the process of nutrition, by the bones from the blood of an ani- 
mal fed upon it ; and, moreover, several acids decompose the salt of lime 
contained in the bones, and extract it without altering the form or com- 
position of the cartilaginous framework.* 

Excluding from consideration the substances which in individual cases 
may be educt or product of chemical analysis, we may with Professor 


body with the more essential proximate principles, as divisible in two 

The first class may consist of binary compounds of mineral substances 
only; such as phosphate of soda, phosphate of lime, phosphate of magnesia, 
carbonate of soda, carbonate of lime, muriate of potash, muriate of soda, 
fluoride of calcium, silica, oxide of manganese, oxide of iron, and soda. 

In the second class are included binary compounds of organic with 
mineral or inorganic substances ; such as the compound which the albumen 
is supposed to form with soda in the blood— albuminate of soda— and the 
salts of lactic acid— lactates of potash and soda. 

The simplest forms in which organic matter appears, have now to be 

The first form is that of complete solution. There are many fluids 
containing organic matter, in which no visible molecules can be discover- 
ed ; such, for instance, is the serum of blood, until it is subjected to the 
influence of heat, galvanism, or different chemical agents. A part of the 
animal matter of the lymph and chyle is also in the state of solution. 

The second form is the state of softness which the solid organised 
tissues present, and which is peculiar to organic beings. The tissues 
derive their properties of extensibility and flexibility from the water, 
which constitutes four-fifths of their weight; although they cannot 
be said to be wet, and do not impart their water to other substances 
so as to moisten them. This water appears, as Berzelius remarks, 
not to be chemically combined in them ; for it is gradually given off by 
evaporation, and can be extracted at once by strong pressure between 
blotting-paper. When deprived of its water, animal matter becomes 
wholly insusceptible of vitality ; except in the case of some of the lower 
animals, which, as well as some plants, revive when again moistened.f 

* Weber, loc. cit. p. 318, 340 

I Berzelius, Thierchemie, p. 7« 




According to Chevreul, pure water alone can reduce organised sub- 
stances to this state of softness; although salt water, alcohol, ether, and 
oil are also imbibed by dry animal textures. Moist animal tissues, by 
virtue of their porosity, allow soluble matters, which come into contact 
with them, to be dissolved by the water which they contain, and which 
fills their pores ; if the matters are already in solution, they are impart- 
ed by their solutions to the water of the tissues. Gaseous substances 
are taken up in the same way. Matters, also, which are contained 
in solution in one tissue, are rapidly imparted to other tissues which can 
dissolve them. The laws of the attraction of substances in solution and 
mixture, the laws governing the uniform distribution of miscible fluids, 
are therefore also applicable in the case of moist animal tissues.* 

Organic substances are during life never crystallized, and the excreted 
matters of animals which are crystallizable, viz. urea, lithic acid, and 
some fatty matters, are never found crystallized in the living tissues, 

although crystallized mineral substances are sometimes observed in the 
cells of plants. 


The organic matter frequently appears in the form of microscopic 
molecules. These organic molecules are observed partly in fluids : 
such are the red particles of the blood which in man measure from 

iVo °f an * nc hj tlle globules of the chyle which measure 

i to 

3 7 LU 

46 00 

7 190 


of an inch according to Prevost and Dumas, and those of the 
i which measure W-™ of an inch, according to Weber. The 

globules of coagulated albumen and fibrin are less distinct. 



even of the tissues of organised bodies, particularly of animals, appear 
to consist of molecules aggregated in the form of fibres, lamellae, and 


membranes. These molecules are most distinct in the brain, and in 
the embryo, for instance, in the germinal membrane of the ovum ; in 
other tissues, it is by no means certain that the appearance of mole- 
cules, observed under the microscope, is not an illusion produced 
merely by inequalities of the surface. The opaque part of the germinal 
membrane in the ovum of the bird is evidently composed of globules 
of considerable size, which are visible with a simple lens and 
perfectly similar to the globules of the yolk : but the vessels which are 


already distributed through the germinal membrane are, according to 
my observations, formed of an incomparably finer matter ; as are also the 
central transparent part of the germinal membrane, the area pellucida, 
and the embryo itself. It appears, indeed, that the germinal membrane 
is formed by the attraction and aggregation of the globules of the yolk ; 
but all the parts developed in this germinal membrane are produced by 
solution of these globules, and conversion of them into a matter in which 
no elementary particles can be distinctly recognised, and of which the 
molecules must at any rate be beyond comparison more minute than 
the globules of the yolk and germinal membrane. 


* See the observations on imbibition in the section on Absorption by the capillaries. 



The ultimate muscular fibre in the frog is five or eight times more 
minute than the red particles of its blood, and more minute even than 
the nuclei of these red particles ; the thickness of the muscular fibre in 
the frog and in mammalia is nearly the same, while the size of the red 
particles of the blood in the two is very different. The diameter of the 
ultimate nervous fibre in mammalia is, according to my observation, twice 
or three times less than that of their blood corpuscules, and is greater 
than that of the nuclei of the blood corpuscules. In the frog, the 

fibre has only 4th the diameter of its blood 




primitive nervous 

puscules, and is therefore much smaller than the nucleus of the blood 

corpuscule. I have not been able to satisfy myself that the nervous 


fibrils consist of globules arranged in a linear form. They certainly 
present successive inequalities, but these inequalities are not regular. In 
fine, this theory of the composition of tissues by the aggregation of glo- 
bules, which are supposed to be more than ^ ^o o °^ a ^ ne * n diameter, 
is rendered exceedingly improbable by the discovery of Ehrenberg, that 
monads, which themselves do not measure more than ^ oW °^ a ^ ne ' have 
compound organs. On account of the difficulty of distinguishing by the 
microscope between inequalities and globules, this theory still remains a 
mere hypothesis. At any rate, the organic molecules are merely the 
most minute forms in which the compound organic matter appears; 
they are not the atoms of the organic combination. 

Source of organic matter. — It is only in organic bodies themselves, 
that the peculiar force which animates them is observed. It is 
manifested only in the organic compounds produced in these bodies; 
the mere accidental coming together of the elementary components is 

not capable of producing organic matter. Fray, it is true, asserts that 
he has observed the formation of microscopic infusoria in pure water ; 
and Gruithuisen says, that he has seen a gelatinous membrane form in 
infusions of granite, chalk, and marble, and infusory animalcules sub- 

sequently appear in this membrane. The fact observed by Retzius* 
is also remarkable ; namely, that a peculiar kind of conferva was gene- 
rated in a solution of muriate of barytes in distilled water, which had 
been kept half a year in a bottle closed with a glass stopper. But, in 
these remarkable cases, it is certain that either the vessels, or the water, 
contained organic matter, in however small quantity ; and, according to 
the experiments of Schultze, the most minute particles of organic mat- 
ter are Sufficient under favourable circumstances to produce the pheno- 
mena which have been regarded as instances of equivocal generation. 

Even animals themselves have not the power of generating organic 
matter out of simple inorganic elements or binary compounds ; they grow 
by the assumption of matter already organised, whether animal or vege- 
table ; they have the power of preserving organic compounds and of con- 
verting one into another, but they cannot produce them. Plants, on 

* Froriep's Notizen, v. p. 56. 













the contrary, seem to be able not merely to assimilate the organic matter 
of animals and plants, but also to generate them from simple elementary 
bodies and compounds of these, such as carbonic acid and water, although 
the presence ofspme_organic matter in the soil, in which plants grow, is 
necessary. It seems impossible to deny this production of organic mat- 
ter from inorganic matter by plants ; for, unless such were the case, 
the nutriment on the earth would be constantly decreasing, since animal 
and vegetable matters are being incessantly converted by combustion, 
putrefaction, &c. into binary compounds. 

The organic matter formed by plants, or that contained in plants and 
animals and modified by them, is capable of again forming a part of 
other living beings, when taken into them and subjected to their vital 
forces. In this manner all the organic matter which is spread over the 
surface of the earth, originates in living beings : death, that is, the ex- 
tinction of the power which produces and maintains organic compounds, 
annihilates the individual ; while the organic matter which formed this 
individual, while it is not reduced to binary compounds, is still capable of 
receiving new life, or, in other words, of nourishing other living bodies. 

Equivocal generation.— The ordinary mode of production of organic 
beings is from others of the same species, by ova or shoots. But it must 
be inquired, whether the organic matter left after the destruction of 
one living body can, under certain circumstances, generate living bodies 
of another kind; whether it is capable, not only of nourishing bodies 
already living, but also of continuing its own life in a modified form ; 
whether, in fact, under certain conditions,— namely, under the influence 
of atmospheric air, water, and light, — small microscopic animals, the 
infusoria, and under other conditions the simplest plants, forming mould, 
are generated from this apparently dead organic matter. 

In a more extended sense the ancients, especially Aristotle, had 
admitted this equivocal generation, this spontaneous formation of 
animals ; for they had an old tradition, that the lower animals, 
insects and worms, were generated during putrefaction. This opinion 

still maintained among the other superstitions of natural his- 
tory and medicine even in the seventeenth century. At that period 
Redi wrote his " Experimenta circa generationem insectorum," in 
which he proved that all the instances of equivocal generation, which 
the ancients had adduced, were erroneous ; that all these worms and 
insects were produced from ova which had been previously deposited. 
His proofs were convincing, and from that time no well-informed natu- 
ralist believed in the fable of generation by putrefaction ; so that the 
proverb " Omne vivum ex ovo," retained its force. Subsequently, how- 
ever, Needham* pointed out, that although no insects are produced by 
putrefaction, yet that, during that process, minute microscopic animals 
till then unknown are generated. If water is poured over animal or 


* Nouv. Observ. Microscop. and « New Microscopic Discoveries," London 1745. 






vegetable substances, and tlie infusion exposed to air and light at the 
usual temperature of summer, after a few days the organic matter will 
have undergone partial decomposition, being in part converted into other 
organic matters, partly reduced to globules, and in part dissolved ; and 
there will appear in it either mould, or those microscopic animals, in 
which Ehrenberg has discovered a very complicated organisation. 

Since the time of Needham, our knowledge of this subject has been 
extended by the observations of Wrisberg, O. F. Miiller, Ingenhouss, G. 
R. Treviranus, Gruithuisen, and Schultze. 

Wrisberg* observed, that no animalcules are produced when atmospheric 
air is excluded, for instance, when the surface of the infusion is covered 
with olive oil. They are generated by an infusion of any animal or 
vegetable matter which contains nothing acrid or acid, and nothing 

which would prevent putrefaction. The development of infusoria com- 
mences as soon as a certain degree of decomposition with escape of gas 
has taken place. , From this time a large number of microscopic mole- 
cules are seen in the infusion $ these molecules are sometimes diffused 
in it, sometimes form a kind of membrane at its surface, and are produced 
by the dissolution of the organic matter. Fray and Burdachf state, that 
infusory animalcules are also generated in an atmosphere of hydrogen and 

Spallanzani and several other physiologists attacked this theory of the 
equivocal generation of animalcules. Spallanzani J explained the pro- 
duction of these animals by supposing ova to have been present in the 
fluid, and to be developed by the influence of warmth, water, air, and 
light. This physiologist's own experiments, however, show that organic 
substances do not lose their property of producing animalcules by being 
boiled, and that distilled water is as well adapted for making the infusion 
as other water. Besides, Spallanzani's experiments merely prove that 


atmospheric air is necessary for the development of these animalcules ; 
and that, when bottles filled with infusions, and hermetically closed, were 
exposed for an hour to boiling heat in vessels filled with water, no ani- 
malcules were afterwards discoverable in these infusions. Spallanzani also 
found that the animalcules differ according to the nature of the infusion* 
From experiments with the seeds of the water-melon, gourd, hemp, and 
millet, it resulted that the number of the infusoria is greater when the 
germ is in the progress of growth, than when the seed is just germinating, 
and that the number diminishes as the seed decays. The smaller kinds 
of animalcules were succeeded by larger, until, after a certain time, the 
power of developing them seemed to be lost. The infusory animalcules 
from uninjured seeds were said to be larger than those from pulverized 
seeds. They were generated from flour quite as well as from seeds merely 
bruised. If, however, the starch of the flour was separated from the 

* Observ. de Anim. Infus. 
Physical, und Mathem. Abhandl. 

t Burdach, Physiologie, t. i 



■-* - 

- - - 



gluten, and an infusion made of each of these substances separately, 
very few animalcules, or none at all, were developed in the infusion of 
starch, while in that of the gluten a host of living animals were seen. In 
infusions of barley, Indian wheat, beans, lupin-seeds, rice, and linseed, no 
animalcules were developed.* But since the genera and species of infu- 
soria are as determinate as those of higher classes of animals, and since 
Spallanzani has not particularized the differences of form of his infusoria, 
since moreover the forms of the infusoria in the different stages of their 
development are not known, Spallanzani's experiments lose much of 
their weight in reference to his discovery of perfectly different animal- 
cules in the infusions of the gourd, chamomile, sorrel, corn, and spelt. 

Treviranus f has, by his numerous and more accurate experiments, 
given a much greater importance to the hypothesis of equivocal genera- 
tion. The following are the grounds of his arguments : 


1. Infusions, with the same water, of different organic substances, — for 
instance, cress-seeds and rye, — give rise to different animalcules. 

2. Light has a very great influence on the process of equivocal 

generation. Thus, the green matter of Priestley, which is remarkable 

for its property of exhaling oxygen, is produced only under the influ- 
ence of light ; when water, particularly spring-water, is exposed to the 
sun in transparent vessels, whether open or close, this matter appears in 
the form of a greenish crust consisting of round or elliptic granules, in 


which crust at first the slight motions of single molecules are discover- 
ed, and afterwards transparent threads moving irregularly. These 



According to 

of green animalcules, the euglena viridis and others, which have died. 
In that case the moving threads would be independent beings, distinct 


from the green matter, and Ingenhouss would have committed the error 
of regarding different kinds of simple beings as different states of the 
same molecules. 

3. The entozoa and the spermatozoa, bodies with tails and spontaneous 
motions, which are seen by the microscope in the seminal fluid, even of 
invertebrate animals, seem to afford arguments for the spontaneous origin 
of living beings in organic matter. 

4. Treviranus found in his own experiments that, under circumstances 
otherwise similar, different organic beings, namely infusoria or mould, are 
formed in different infusions; and he found that these differences did not 

depend on the water, but on the substances infused in it. 

5. Treviranus observed that in one and the same infusion, under 
different accidental conditions, different animalcules were developed ; 
thus, from an infusion of the leaves of the iris with fresh spring- water, in 
a long vessel covered with linen, and exposed to the sun, infusory ani- 

* Treviranus, Biologie, ii. pp. 279, 280. f Biologic, ii. p. 264—406. 

$ Vermischte Schriften phys. medic. Inhalts, 




malcules were generated; in another vessel, placed in another situation, the 
green matter of Priestley was formed. Thus also the products in the same 
infusion of rye with spring- water were different, when Treviranus placed 
a bar of iron in one of the vessels. This result seems to agree with that 
of Gleditsch, who found that in separate portions of melon covered with 
muslin, and placed at different heights, the various living organic sub- 
stances, namely mould, byssus, and tremellae, were produced in different 
proportions. To this might be added, that Gruithuisen states that he 
has found perfectly different animalcules in infusions of pus and mucus. 

From all these facts Treviranus has inferred, that throughout all 
nature there exists an absolutely indecomposible, indestructible ( ?) 
organic matter which is constantly active; which gives life to every thing 
living, from the byssus to the palm, and from the point-like infusory 
animalcule to the monsters of the deep ; and which, in its essence un- 
changeable, is constantly changing its form : that this matter has itself no 
proper form, but is capable of assuming every form of life ; that it receives 
a determinate form only under the influence of external causes, retains 
this form only during the continuance of these causes, and takes another 
form as soon as other causes act upon it. According to Wrisberg and 
others, the animalcules are formed from particles which separate from 
the substance infused, and which gradually begin to move ; while 
Gruithuisen* says, that they appear first in the solution of extractive 
matter obtained by the action of the water on the infused substance. 
Professor Schultze f says, "I have never seen a globule of blood, or of 
milk, or of cerebral substance, begin to move about in their several 
infusions, as a monad, or become changed into one. Every single globule, 
by its solution, affords matter for the production of several hundred 
monads." This last observation, however, does not agree with the results 
of measurement ; for Ehrenberg estimates the smallest visible monad at 

of a line, that is -^ 


about ^o 

of human blood are only 3 7 4 

globules of the milk are still smaller. 

of an inch ; while the corpuscules 
q\q of an inch in diameter, and the 

Schultze states that he has 


observed the conversion of dust-like particles of organic matter into 
infusoria; these particles in the water become, he says, in a few hours 
surrounded by a turbid ring which extends until the particle is quite 
dissolved ; this ring separates into monads. 

Equivocal generation not proved by these observations. — If we criticise 
the observations of these observers, we shall find that the mode in which 
the experiments have been performed do not leave the results free from 

1. In the experiments made with boiled organic matter, in the air, it 
is not certain that the infusoria or mould did not arise from the dust of 

* Gruithuisen, Beitrage zur Physiognosie und Eautognosie. Miinchen, 1812. 8vo. 

+ C. A. S. Schultze, Microscop. Untersuchungen uber R. Brown's Entdeckung le- 

bend. Theilchen in alien Xvorpern, und fiber Erzeugung der Monaden. Carlsruhe, 1824. 

"J*-** ^»"« 





desiccated animalcules, or their germs, floating in the air. Perhaps, as 
Humboldt remarks,* when waters on the surface are dried up, the winds 
take up the germs of the simplest organic beings, which, being received 
by other water in the form of dust, are revivified, as in the well known 
and attested fact of the revivification of the wheel-animalcule, first 
observed by Spallanzani. The fact of the dust which floats throughout 
the air containing particles which swell when moistened, has very recently 
been applied by Schultze to explain the production of infusoria; he regards 
these particles as monads which have been dried, and which when 
moistened recover life. Schultze, however, does not consider this very 
frequent source of infusoria as the only one ; he admits the conversion of 
organic substance into protozoa. 

2. The equivocal generation of infusoria is not better proved by the 
experiments in which boiled organic substances and common water were 
used ; for the water may have contained the ova of infusoria, or animal- 
cules themselves, which have afterwards multiplied very rapidly at the 
expense of the organic matter in the infusion. The use of perfectly pure 
distilled water can scarcely be presupposed, for even water distilled five 
times may still contain organic particles. 

3. Those who have experimented with fresh organic substances and 
distilled water, or even artificially prepared gases, cannot prove that the 
ova of animalcules, or animalcules themselves, were not in some way 
contained in the organic substance : the microscopic animalcules which 
are known to exist in living tissues are indeed few, and the common 
globules of the organic fluids, such as those of the blood, have certainly 
no individual life ; but mucus itself contains microscopic animals ; the 
intestinal mucus of the frog, as well as the semen, contains animalcules. 
Baer has seen microscopic particles moving spontaneously at different 
spots in the muscles. f The grain of wheat, and some varieties of agros- 
tis, often contain vibriones, which even after being dried recover their 
active life if moistened. Some animalcules also which are met with in 
other animals, but especially the epizoa, will continue to live when placed 
in water. 


4. Lastly, although some experimenters should have employed organic 
substances long boiled, with distilled water and artificially prepared air 
at the same time, still the accuracy necessary for a sure result is neither 
probable nor generally possible, since every instrument used for changing 
the water ought to be absolutely free from particles of organic matter, 
and every cleansing is a source of errors. 

Ehrenberg s observations are opposed to the theory. — These remarks do 
not disprove the existence of the equivocal generation ; they merely show 
that it is scarcely possible to prove it by direct experiment. The inves- 
tigations of Ehrenberg, however, relative to the organisation of these 

* In liis Ansichten der Natur. 

t See Nov. Act. Nat. Cur. 13. 2. p. 594 




; ■- - • 





animals and plants, which are supposed to be generated in this equivocal 
manner, have thrown new doubt upon the theory. In the first place 

smallest monad 

2 000 

Ehrenberg discovered the real germs of the fungi and mould.* Th 
propagation of these organic bodies was thus established; it was shown 
that, by means of the germs or seeds of the mould, new mould can be 
produced, which rendered it probable that the cases of the unexpected 
production of mould arose merely from seeds, which had been diffused in 
the atmosphere or water, having then found the situation required for 
their development. With regard to the infusory animalcules, their com- 
plicated structure was first discovered by Ehrenberg ; he found that the 

of a line in diameter has a complicated stomach, and 
organs of motion, in the form of cilia. In others he observed the ova, 
and the propagation by ova. This excited the greatest doubt with regard 
to those earlier observations, in which, the complicated structure of these 
animalcules being unknown, they were said to have been seen to ori- 
ginate in particles of the organic substance of the infusion. Ehrenberg 
has never succeeded in obtaining determinate forms of infusoria, accord- 

* "I 

mg to the nature of the infusion ; and even by the most similar modes 
of performing the experiment, sometimes one, sometimes another set of 
animalcules were obtained. Ehrenberg believes that there are certain 
forms, of which the number is limited, which are most widely diffused ; 
the ova or individuals of these forms may exist in all waters, even in 
some parts of plants, but perhaps only in the noxious parts ; and of these 
forms different kinds may be much multiplied, according to the kinds of 
ova or individuals which were in the water, or were introduced into it. 
The increase of these animals appears to be extraordinarily rapid. A 
single wheel-animalcule, Hydatina Senta, which was watched for more 
than eighteen days, and which lives still longer, is capable of a four -fold in- 
crease in twenty-four or thirty hours. This rate of increase affords in ten 
days a million of beings. This, in some measure, explains the extraordi- 
nary number of infusoria in a drop of an infusion. Ehrenberg never ob- 
served any animalcules in dew or rain ; but he has found some in 
Africa and Asia as well as in Europe, in sea water as well as in river 
water, in the depths of the earth and at its surface. During their de- 
velopment, however, these animals seem to present many forms, and the 
forms dependent on the different stages of development of one animal- 



1 , . JL ~».-.~^* vxt« WWVV/1UO* J. 1 UHI 

these observations Ehrenberg concludes, that all infusoria are, like other 
animals, propagated from ova,-omne vivum ex ovo,-and leaves it un- 
decided whether the ova are, or are not, in part really the product of 
a generatio primitiva.f 

■ * Nov. Act. Nat. Cur. t. x. See also Ness. v. Esenbeck, Flora, 1826, p. 531 • and 
Schilling in Kastner's Archiv. x. p. 429, ' ? 

+ Ehrenberg in Poggendorf's Annal. 1832. 1. See also Wagner in the Isis for 
1832. Wagner regards as certain, the transformation of infusoria into the green 














.Facte relating to Entozoa, favourable 


primitive formation of certain animals from animal matter, till then un- 
organised, is still best supported by the facts regarding the entozoa. A 
complete series of arguments in favour of equivocal generation rests 
upon the impossibility of explaining the first production of entozoa, 
without supposing a spontaneous generation. 1. The immense majority 
of the intestinal worms are quite distinct in their organisation from all 
the beings which are met with out of the animal body. The similarity 
of some distomata to the planarise of fresh and salt water is only apparent. 
2. A small number only of intestinal worms occur in different genera of 
animals. Thus the Taenia of man is peculiar to him ; on the contrary, the 
Distoma Hepaticum, the hydatid of the liver, seems to be common to 

the hare, cow, camel, deer, horse, and hog; the thread-worm, 
Ascaris Lumbricoides, is common to man, the hog, ox, and horse. 
Most animals have their peculiar intestinal worms, differing specifically 

from those of others, 
ticular organs. 


3 e Many of these entozoa occur only in par- 
4. Intestinal worms generally die when removed from 
the animal body. 5. They have been observed even in the embryo. 
6. The fact of animals, which feed on vegetables solely, having never- 
theless their own peculiar entozoa, proves that these entozoa, or their 
o-erms, cannot be introduced with the food. In carnivorous animals this 
introduction of the entozoa from without can be admitted in very few 
cases only ; such are the facts of the Echinorhynchus of the field-mouse 
having been sometimes found in the falcon, the worms of the frog in ser- 
pents, the Ligula of fishes, the Bothriocephalus solidus of the stickleback, 
in the intestines of wading and swimming birds. But many other ento- 
zoa are met with in other parts than the intestinal canal, and beyond the 
reach of matters introduced from without.* 

Ehrenberg endeavours to set aside the equivocal generation of the 
entozoa, inclining to the old opinion that the ova of these animals cir- 
culate with the fluids in all parts of the body. He assumes that, since 
the generative organs of the entozoa contain a great number of ova, 
these ova are carried by the circulation into all parts of the body ; so that 
all the fluids are, as it were, infected with the ova of the entozoa, which 
are seated in particular organs. The milk with which other individuals 
of the same species are nourished, may itself contain the ova of these 
worms. The embryo of mammalia in which entozoa already exist, may 
receive the ova from the fluids of the mother. Entozoa have been 
found in the eggs of birds. Eschscholz found them in hen's eggs.f It 


matter of Priestley, as many persons have described. This green matter, however, 
is nothing more than the remains of dead infusoria, the euglena viridis. The conver- 
sion of this green matter into confervas, ulvje, tremellee, or even mosses, is doubted by 
Wagner, and with justice. ■ 



•J- Burdach's Physiologie, i. p. 22. 




is possible that they may have originally found their way thither from the 
fluids of the mother ; but, in fact, the suppositions on which the equi- 
vocal generation is here sought to be refuted, are as improbable as that 
theory itself. The ova of the entozoa are evidently too large to enter the 
lymphatics of the organ in which the worms live ; they are much too large 
to circulate in capillary blood-vessels, of which the diameter is only wouv 
of an inch, or in fine to pass into the secretions, — the milk, or yolk of "the 
egg, for example : the explanation of the occurrence of entozoa in herbi- 
vorous animals, by transmission from mother to young, is consequently 
completely opposed to the known data afforded by the micrometer, un- 
less it be admitted, that the smallest particle of the germinal matter 
formed by entozoa already existing is as capable of propagating them as 
an entire ovum. With regard to the spermatozoa, Ehrenberg assumes 
that every animal receives them at the time of fecundation. 

M. Von Baer * has observed many other extraordinary circumstances 
in the generation of the entozoa. The animals which he names Buce- 
phalus, are generated in thread-like ovistocks, which are found in mus- 
cles ; and Bojanus and Baer have described a worm, found in the lym- 
naeus stagnalis, which again contains numerous animals of a perfectly 
different form,— the cercaria. Nordmannf has seen monads in the body of 
living intestinal worms, namely, diplostomata ; and has seen infusory ani- 
malcules produced in the interior of the putrefying ova of lemsese. On the 
other hand, the changes which certain entozoa undergo deserve atten- 
tion; for example, the ligula and bothriocephalus solidus of fishes have 
no distinct genital organs until they are received into the intestines of 
water birds : some young distomata have at first a different form from 
that which they afterwards present ; thus the distoma nodulosum of the 
perch has, according to Nordmann, at first no sucker, and is, then, pro- 
vided with a trace of an eye and with cilia, as if to swim in water. The 
infusoria and entozoa of living plants still require investigation. It is 
important to know, that the diseased grain of agrostis or bent-grass, 
phalaris or canary-grass, and wheat, contain, according to SteinbuchJ 
and Bauer,§ vibriones ; that Bauer, having inserted vibriones into the 
stem of the young wheat, found them again in the grain ; and that the 
worms of the dried seeds, according to the same observers, if placed in 
water after several years, will again present all the phenomena of life. 

of organic matter and of the organic f 


In the production 

of infusoria there is no new formation of organic matter ; the previous 
existence of organic beings is presupposed. Organic matter is never 
produced spontaneously. Plants alone seem to have the power of ^ 
nerating ternary or organic compounds from binary or inorganic com- 
pounds ; while animals are nourished only by organic matter, which 

* Nov. Act. Cur. xm. 2. 

* Aaialecten. 1802. 

f Microgr. Beitrage. Berlin, 1832. 

§ Philos. Trans. 1823. 







they cannot generate from binary compounds, and consequently their 
existence presupposes that of the vegetable kingdom. How organic 
beings were originally produced, and how organic matter became en- 
dowed with a force which is absolutely necessary to the formation and 
preservation of this organic matter, but which is manifested only in it, 
it is beyond the compass of our experience and knowledge to determine. 
The difficulty is not removed by saying that the organic force has re- 
sided in the organic matter from eternity, as if organic force and organic 
matter were only different ways of regarding the same object: for, in 
fact, the organic phenomena are presented only by a certain combina- 
tion of the elements ; and even organic, matter, itself susceptible of life, is 
reduced to inorganic compounds as soon as the cause of the vital phe- 
nomena, namely, the vital force, ceases to exist. This problem, however, 
is not a subject of experimental physiology, but of philosophy. Conviction 
in philosophy and in natural science has entirely different bases ; the 
first suggestion here, therefore, is, not to be led away from the field of 

rational experiment. We must be content to know that the forces which 
give life to organic bodies are peculiar, and then examine more closely 
their properties. 

i i 

r * 

2. Of Organism and Life. 

Organised beings are composed of a number of essential and mutually 
dependent parts. — The manner in which their elements are combined is 
not the only difference between organic and inorganic bodies ; there is 
in living organic matter a principle constantly in action, the operations 
of which are in accordance with a rational plan, so that the individual 
parts, which it creates in the body, are adapted to the design of the 
whole ; and this it is which distinguishes organism. Kant says, " The 
cause of the particular mode of existence of each part of a living body 
resides in the whole, while in dead masses each part contains this cause 
within itself." This explains why a mere part separated from an organ- 
ised whole generally does not continue to live ; why, in fact, an organ- 
ised body appears to be one and indivisible. And since the different 
parts of an organised body are heterogeneous members of one whole, and 
essential to its perfect state, the trunk cannot live after the loss of one 

of these parts. 

It is only in very simple animals or plants which possess a certain 
number of similar parts, or when the dissimilar parts are repeated in 
each successive segment of the individual, that the body can be divided, 
and the two portions, .still possessing all the essential parts of the 
whole, though in smaller number, continue to live. Branches of plants 
separated from the trunk, being planted, form new individuals. The 
different parts of plants are so similar,, that they are convertible one 











into another, branches into roots, and stamens into petals.* This is 
the case also with some simple polypes. The experiments of Trembley, 
tioesel, and others, prove that portions of a divided polype will continue 
to grow until each half becomes a perfect animal. In the same way some 
worms, as the naides, in which each segment contains nearly the same 
essential parts,— the intestine, nerves, and blood-vessels,— have been ob- 
served to propagate by spontaneous division. Bonnet states, that he 
has seen this new growth and reproduction in the portions of a divided 
earthworm ; but this animal, when thus divided, could not continue to 
live for neither portion would contain all the parts essential to the 



whole. \t£> 






In the higher animals, and in man, there are certain organs,— that 
parts differing in their properties and functions,— which cannot be 
removed without destruction of life, and of our idea of the whole ; and 
such organs also only occur singly, as brain, spinal marrow, lungs, heart, 
and intestinal canal. Other parts, on the contrary, which are not mem- 
bers essentially necessary to our conceived idea of the whole, or which 
are several in number, may be removed with impunity : no part, how- 
ever, of one of the higher animals can continue to live when separated 
trom the body, for no one part contains all the organs essential to the 
whole. The ovum, the germ itself, alone possesses this power ; for, at 
the time of its separation from the parent animal, the vital force has 
not formed in the germ the essential parts of the whole ; and yet, when 
separated from the original being, it forms a new integral being. There ^ 
is then in the organism a unity of the whole, which governs its formation 
out of dissimilar parts. From the facts we have stated, however, it 

appears that organised bodies are not absolutely indivisible ; they may 
indeed always be divided, and still retain their properties, if e'ach portion 
contains the essential heterogeneous members of the whole, and in the 
generation even of the highest animals and plants a division takes place. 
m of inorganic bodies are homogeneous and independent of each 

Inorganic bodies are divisible in a much more extended sense, 
without the parts losing the chemical properties of the whole: they may 



(to use the common expression) ad infinitum 

--, — that is, ac- 
cording to the atomic theory, into the ultimate atoms which, on account 
of their minuteness, elude the senses ; and in chemical compounds into 
molecules which are formed of the different component atoms, and which 
are likewise not recognisable by the senses. 

There are, however, even among inorganic bodies, some which cannot 
be reduced by division to their ultimate particles without losing some 
of their properties; I mean the crystals. These bodies can be di- 
vided with facility only in certain directions, and the portions thus ob- 

* Goethe, Metamorphose der Pflanzen. 


*^\^<~ ' / Kv«^i L \rU- 



•t^ In^-tcLc) \sAJ^ , 


L-~Cvl<s7 J 





-uJr Ic L. 




be - 






tained are often different in form from the whole; for which reason 
some persons regard crystals also as "individuals," which exist from the 
continuance of the force which formed them, and cease to exist when 
external, chemical (atmospheric), or mechanical influences overcome 
their force of crystallisation or hardness.* But even if crystals are re- 
garded as individuals in this sense, there is still this great distinction be- 
tween them and organised bodies, — that the molecules of crystals are 
homogeneous throughout, and that crystals are divisible, at least, into 
homogeneous aggregates ; while organised bodies are composed of per- 
fectly different members of one whole, such as tissues endowed with 


peculiar properties. Organic combinations, moreover, never occur in a 
state of crystallisation in organised bodies during life. Again, in an in- 
organic body which is composed of heterogeneous substances aggregated 
together, these parts have no reference to the design and existence of 
the whole. 

Adaptation displayed in organised bodies. — - Organised bodies being 
composed of a certain number of dissimilar essential parts all adapted to 
the plan of the whole, it necessarily follows that the external and internal 
comformation of themselves and of their organs are such as to distinguish 
them entirely from inorganic bodies. That which we admire in the 
whole animal is not merely the manifestation of the ruling forces, as 
crystallisation is the consequence and manifestation of a certain force in 
a binary compound ; but the form of the animals and of their organs 
evidences also an arrangement rationally adapted to the exercise of the 
forces, a most excellent harmony of the organisation with the faculties 
intended to be exercised. Crystals, on the contrary, present no adap- 
tation of form to an intended action of the whole, because the whole 
crystal is not a body composed of a number of dissimilar adapted tissues, 
but is produced merely by the aggregation of similar elements or for- 
mative particles, all subject to the same laws of crystalline attraction. 
Crystals, therefore, increase by the aggregation of new particles on the 
external surface of the parts already formed ; while in the organised 
body the formation of the parts situated side by side, each having a 
different organisation, is for the most part contemporaneous ; so that the 
growth of organised bodies takes place in all particles of their substance 
at the same time, while the increase of the mass in inorganic bodies is 
produced by external apposition.t 

This law of organic conformation, 

/ 0^ -Hu, ^/^ T' <-*42^J Ov^U^n^ 

adaptation to aa-e»d, 


the form, not only of entire organs, but also of the simplest elementary 
tissues. Thus it will in a future page be shown, that the manifold 


* See Mobs, Grundriss der JVI ineralogie, i. Vorrede, p. 6. 

-j- Professor E. H. Weber has made some other very interesting comparisons be- 
tween organisation and crystallisation in his General Anatomy. Hildebrandt's Anat. 

pter Band. 





forms of secreting glandular structures depend simply on the various 
modes in which a large secreting surface can be realised in a small 
space. The fibrous structure of muscles is necessary to enable these 
organs to shorten themselves in a determined direction by the zigzag 
flexure of the fibres. Thus also in treating of the Physiology of the Nerves 
it will be shown, that unless the nerves had been divided into a certain 
number of primitive fibres, which do not communicate one with another, 
their local action,— local circumscribed sensation,— would be impossible, 
ine same adaptation is seen to be equally necessary in the organisation 

of plants. The organs of plants are 1 

heterogeneous, and, in place of 

being so much enclosed in the interior, are expanded on the surface — 
the reciprocal actions with the external world being effected by the whole 
surface rather than by particular points ; hence the general character 
of the conformation of plants is a surface increasing in perfect conformity 
with the intended purpose, this surface being presented in the manifold 
forms of the leaves; the individual forms in which the increase of surface 
is effected are more numerous than the most lively fancy can imagine, 
and a great part of terminology is only an attempt to form logically, a 
plan conformable to nature, of the possible varieties in the increase of 
surface obtained by variations of the leaves, and of their relation to pe- 

dicle, twig, branch, and stem. 


The only character 



that can be possibly compared in organic and inorganic bodies, is the 
mode in which symmetry is realised in each. Crystals have symmetrical 
and asymmetrical surfaces, angles and corners. Animals have also sym- 
me nca and asymmetrical parts, and the laws of symmetrical and asym- 
metrical conformation in organised bodies present similar manifold 

The original form of the animal germ, for example, is a 
roundish flat disk, •'••-- 

bird's egg ; this germinal disk, white in the ovary, appears" from the 
researches of Purkinje and Baer, to be a vesicle. The germ is also 
disk-shaped m invertebrate animals, as I have seen in the planaria. The 
torm of the ovum and yolk must not be confounded with that of the 
germ. The forms developed from the germ, however, are very various. 
*or instance, we recognise first a radiate symmetrical type in the radiata, 
similar parts being arranged around a common point ; the anterior and 
posterior surfaces of the body being the only asymmetrical parts. Secondly, 
we distinguish^ symmetry of similar parts in an arborescent type, as 
presented by the leaves and flowers in plants, and by the polypes on the 
branched stem in polypiferous animals. Thirdly, we distinguish the suc- 
cessive symmetry m the succession of similar parts from before backwards 
in worms, in which the only want of symmetry is between the dorsal and 
ventral surfaces. Fourthly and lastly, we recognise the lateral symmetry 
in the repetition of similar parts on each side, in man and the higher 







animals ; here the want of symmetry is seen in the organs taken from 
before backwards, and in the dissimilarity of the dorsal and ventral sur- 
faces. In many animals the lateral symmetry is in part combined with 
the successive symmetry, which is seen in the vertebrae of the higher 
animals. In addition to the circumstance that the symmetry and asym- 
metry of crystallised inorganic bodies are always represented by plane 
surfaces and straight lines, the reverse of which is the case in organised 
bodies, there is also this great difference, that the symmetrical and asym- 
metrical parts of crystals have a simple composition, while the symme- 
trical parts of organised bodies are themselves in the first place formed 
of heterogeneous tissues. The causes which give rise to the different 
types of organic symmetrj', just mentioned, and which first determine in 
the germ the position of the axis for the symmetrical developement, are 
as difficult to imagine as the causes of the symmetry of form in crystals. 
The elementary particles of the organised body are, moreover, never 
crystalline ; for although some kinds of fatty matter are crystalline in 
the pure state,, it is only when they are subjected to external influences 
and withdrawn from that of life. The same is the case with sugar, urea, 
and lithic acid. Most of the organic substances and fluids do not crys- 
tallise even when removed from the living body. The spinal canal and 
the cranial cavity of the frog have, surrounding the central parts of the 
nervous system, a layer of white pulpy matter which, according to Eh- 
renberg and Huschke, consists of microscopic crystals of carbonate of 
lime. In the peritoneum of fishes, and in the tapetum of the choroid 
of the same animals, Ehrenberg* has also discovered microscopic crys- 
tals of organic matter. 

[Professor Schoenlein t has discovered, in the intestinal excretions, and 
in the yellow crusts covering the excrescences of the mucous membrane 
in typhus abdominalis, which are supposed to be Peyer's follicles, a great 
number of small crystals, which consist chiefly of phosphate of lime, 
some sulphate of lime, and a salt of soda. In other kinds of fevers and 
of diarrhoea, and in healthy persons, the faeces contained no crystals. 

Valentin J 


the egg of the lacerta viridis.] 
Hitherto I have examined merely 


that peculiarity of organised bodies which consists in their being systems 
of dissimilar organs, the existence of each of which has its source, not 
in itself, but in the entire system, as Kant expressed it. The organic 
force, which resides in the whole, and on which the existence of each part 
depends, has however also the property of generating from organic matter 
the individual organs necessary to the whole. Some have believed that 
life, — the active phenomena of organised bodies, — is only the result of 


M'uller's Archiv. fur Anat. und Physiolog. 1834, p. 158. 

t Ibid. 1836, p. 258. 

% Ibid. p. 256. 




the harmony of the different parts — of the mutual action, as it were, of 
the wheels of the machine, — and that death is the consequence of a dis- 
turbance of this harmony. This reciprocal action of parts on each other, 
evidently exists ; for respiration in the lungs is the cause of the acti- 
vity of the heart, and the motion of the heart at every moment sends- 
blood, prepared by respiration, to the brain, which thus acquires the* 
power of animating all other organs, and again gives occasion to the 
respiratory movements. The external impulse to the whole machinery is 
the atmospheric air in respiration. Any injury to one of the principal 
moving powers in the mechanism, every considerable lesion of the lungs, 
heart, or brain, may be the cause of death ; hence these organs have been 
named the atria mortis. But the harmonious action of the essential parts 
of the individual subsists only by the influence of a force, the operation 
of which is extended to all parts of the body, and which does not depend 
on any single parts ; this force exists before the harmonizing parts, which 
are, in fact, formed by it during the developement of the embryo. A 
complicated piece of machinery, constructed in adaptation to an end, — for 
example, a watch,— may present an action resulting from the co-opera- 
tion of individual parts, and originating in one cause : but organic beings 
do not merely subsist by virtue of an accidental combination of elements ; 
the vital force inherent in them itself generates from organic matter the 
essential organs which constitute the whole being. This rational creative 
force is exerted in every animal strictly in accordance with what the 
nature of each requires. 

force exists already 

of the ft 

The germ is "potentially" the whole 

animal ; during the developement of the germ, the essential parts which 
constitute the "actual" whole are produced. The developement of the 
separate parts out of the simple mass is observable in the incubated egg. 
All the parts of the egg, except the germinal membrane or blastoder- 
ma, are destined for the nutrition of the germ ; the entire vital principle 
of the egg resides in the germinal disk alone, and since the external 
influences which act on the germs of the most different organic beings 
are the same, we must regard the simple germinal disk, consisting of 
granular amorphous matter, as the « potential" whole of the future animal, 
endowed with the essential and specific force or principle of the future 
being, and capable of increasing the very small amount of this specific 
force and matter which it already possesses, by the assimilation of new 
matter. The germ expands to form the germinal membrane, which grows 
so as to surround the yolk; and by transformation of this germ the organs 
of the future animal are produced, the elements merely of the nervous and 
vascular systems, and of the intestinal canal, being first formed, and from 
these elements the details of the organisation afterwards more fully de- 
eloped; so that the first trace of the central parts of the nervous system 










U^ p^u^ C 

4 l^^AxfLA 







must be regarded neither as brain nor as spinal marrow, but as the still 
"potential" whole of the central parts of the nervous system. In the 
same manner the different parts of the heart are seen to be developed 
from a uniform tube ; and the first trace of the intestinal tube when there 
are no salivary glands and liver, is more than the mere intestinal tube ; it 
is the "potential" whole, — the representative of the entire digestive ap- 
paratus ; for, as Baer first discovered, liver, salivary glands, and pancreas 
are in the further progress of the vegetative process really developed from 
that which appears to be merely the rudiment of the intestinal canal. It 
can no longer be doubted that the germ is not the miniature of the future 
being with all its organs, as Bonnet and Haller believed, but is merely 
"potentially" this being, with the specific vital force of which it is endued, 
and which it becomes " actually" by developement, and by the production 
of the organs essential to the active state of the " actual" being. For the 
germ itself is formed merely of amorphous matter, and a high magnifying 
power is not necessary to distinguish the first rudiments of the separate 
organs, which from their first appearance are distinct and pretty large, 
but simple; so that the later complicated state of a particular organ can 
be seen to arise by transformation from its simple rudiment. These 
remarks are now no longer mere opinions, but facts; and nothing is more 
distinct than the developement of glands from the intestinal tube, and 
of the intestinal tube itself from a portion of the germinal membrane. 

The creative organic force is not, like the mind, connected with one special 
organ. — If Ernst Stahl had been acquainted with the above facts, he 
would have been still more confirmed in his famous theory, that the 
rational soul itself is the primum movens of organisation ; that it is the 
ultimate and sole cause of organic activity ; that the soul constructs con- 
formably to design, and preserves its body in accordance with the laws 
of its operation; and that by its organic action the cure of diseases is 
effected. Stahl's contemporaries and followers have partly misunderstood 
this great man, in believing that, according to his view, the soul, which 
forms mental conceptions, also conducts with consciousness, and design- 
edly, the organisation of the body. The soul (anima) spoken of by Stahl is 
the organising power or principle which manifests itself in conformity with 
a rational law. But Stahl has gone too far in placing the manifestations 
of soul, combined with consciousness, on a level with the organising 
principle ; the operations of which, though in accordance with design, 

obey a blind necessity^/ The organising principle, which according to an 

creates the different essential organs of the body, and animates 
them, is not itself seated in one particular organ ; it continues in opera- 
tion up to the time of birth in^anencephalous monsters; it modifies the 

other organs in the 

already existing nervous system, as well as^a 

larvae of insects, during their transformation, causing the disappearance 

of several of the ganglia of the nervous cord, and the union of others ; 






by its operation during the transformation of the tadpole to the frog, the 
spinal marrow is shortened in proportion as the tail becomes atrophied, 
and the nerves of the extremities are formed. This principle, thus acting 
Conformably to design, but without consciousness, is also manifested in the 
phenomena of instinct. There is great beauty and truth in the saying 
of Cuvier, that animals acting from instinct are, as it were, possessed by 
an innate idea, by a dream . But that which excites this dream can 
be nothing else than the organising principle, the « final cause" of the 




The existence of the organic principle in the germ, and its apparent 
independence of any special organ in the adult, as well as the fact that it 
is manifested in plants, in which both nervous system and consciousness 
are wanting, prove that this principle cannot be compared with mental 
consciousness, which is an after product of developement, and has its 
seat in one particular organ. Mind can generate no organic products, it 
can merely form conceptions ; our ideas of the organised being are mere 
conscious conceptions of the mind. The formative or organising princi- 
ple, on the contrary, is a creative power modifying matter, blindly and 
unconsciously, according to the laws of adaptation. 

genera and species.— Organism, or the organised state, is 

e result of the union of the organic creative power and organic matter. 
Whether the two have ever been separate, whether the creative arche- 
types, the eternal ideas of Plato, as he taught in his « Timaeus," have at 
some former period been infused into matter, and from that time for- 
ward are perpetuated in each animal and plant, is not an object of 
science, but of the fables and traditions which cannot be proved, and 
which distinctly indicate to us the limits of our me 




All that is known is, that each form of animal or plant is continued un- 
changed in its products, and that, in a roughly calculated number of 
many thousand species of animals and plants, there are no true trans- 
itions of one species to another, or of one genus to another; each 
tamily of plants and animals, each genus, and each species, is connected 
with certain physical conditions of its existence, with a certain tern- 
perature, and with determinate physico-geographical relations, for which 
it is, as it were, created. In this endless variety of creatures, in this re- 
gularity of the natural classes, families, genera, and species, is manifested 
one common creative principle, on which life generally throughout the 
world depends. But all these varieties of organism, all these animals, 
which are as it were so many modes in which the surrounding world 
may be enjoyed by means of sensation and reaction, are, from the mo- 
ment of their creation, independent. The species perishes when the pro- 
ductive individuals are all destroyed; the genus is no longer capable of 
generating the species, nor the family of restoring the genus. In the 
course of the earth's history, species of animals have perished by the 







revolutions of its surface, and have been buried in the ruins ; these belong 
partly to extinct genera, partly to genera still existing. 

The study of the successive strata of the earth, in which the remains 
of organic beings occur, seems to prove that the beings, which have 
thus left their remains on the earth, have not all existed at the same 
time, that the simplest creatures have first inhabited the earth ; while 
the remains of the higher animals, and particularly those of man, are 
not met with except in the most superficial of the deposits which 
contain organic remains. But no fact justifies us in speculations con- 
cerning the original, or subsequent origin of living beings ; no fact 
indicates the possibility of explaining all these varieties by transformation, 
for all creatures maintain unchanged the forms which they originally re- 

Nature of the organic ft 

The unity resulting from the combination 

of the organising force with organic matter could be better conceived, if 
it could be proved that the organising force and the phenomena of life 
are the result, manifestation, or property of a certain combination of 
elements. The difference of animate and inanimate organic matter would 
then consist, in that state of combination of the elements, which is neces- 
sary to life, having in the latter undergone some change. Reil has stated 
this bold theory in his famous treatise on the Ci vital energy/'* which 
some physiologists, — Rudolphi, for example, — regard as a masterpiece, on 
which the principles of physiology must be founded. 

Reil refers the organic phenomena to original difference in the ele- 
mentary combination and form of the organic bodies. Differences in 
the mode of combination of the elements and in form, are, according to 
his theory, the cause of all the variety in organised bodies, and in their 
endowments. But if these two principles be admitted, still the problem 
remains unsolved ; it may still be asked, how the elementary combina- 
tion acquired its form, and how the form acquired its elementary com- 
bination. That the form of the organic matter does not determine 
originally the mode of its action, is proved indisputably by the fact, 
that the matter from which all animal forms are produced is at first 
almost without form. The germ in all vertebrata, and probably also in 
the invertebrata, from what is known of a few species, and from what I 
have observed in the planaria, is a round disk of simple matter ; here is 
no difference of form corresponding to the difference of the animals. 
On the other hand, the form of inorganic bodies is always determined 
by their elements, or by the combination of their elements. And this 
Reil himself admits ; for he says : " Form of matter is itself a phenomenon, 
which depends on another phenomenon, namely, the elective affinity of 
the elements and their products." Hence it would follow, that if the 
elementary combination were alone the cause of the organic forces, this 

* Rett's Archiv. fur Physiologic, i. Bd. 


* , 







elementary combination itself would be at the same time the formative 
principle. Now, since in organised bodies immediately after death the 
elementary combination does not appear to be different from that of 
bodies still living, Reil must admit the existence of other more sub- 
tile matters not recognisable by chemical analysis, which are present in 
the living body, but are wanting after death. Into the composition of 
the organic matter of the living body there must enter an unknown 
(according to Reil's theory, subtile material) principle, or the organic 
matter must maintain its properties by the operation of some unknown 
forces. Whether this principle is to be regarded as an imponderable 
matter, or as a force or energy, is just as uncertain as the same ques- 
tion is in reference to several important phenomena in physics ; phy- 
siology in this case is not behind the other natural sciences, for the 
properties of this principle in the functions of the nerves are nearly as 
well known as those of light, caloric, and electricity, in physics. 

At all events, the mobility of this principle is certain. Its motion 
evident in innumerable vital phenomena. Parts frozen, stiff, and 
deprived of sensation and motion, are observed gradually to recover 
animation, which extends into them from the borders of the living parts. 
1 his passage of the vital principle from one part to another, is seen 
still more clearly on the removal of pressure from a nerve, after that 
state has been produced in which the limb is said to be « asleep." The 
fibrin effused in inflammation on the surface of an organ, is observed to be- 
come endowed with life and organisation. This organic principle exerts 
its influence even beyond the surface of an organ, as is shown by the changes 
produced m the animal matter contained in the vessels, for instance, in 
the lymph and chyle, which latter fluid during its progress through the 
lacteals acquires new properties; from the coats of the blood-vessels 
again, the organic principle exerts an influence on the blood, maintaining 
its fluidity, for out of the vessels the blood coagulates under almost all 
circumstances, unless it has undergone some chemical change. Lastly 
I may with Autenrieth adduce that property of animal tissues, by virtue 
ot which vital energy is at one time withdrawn from them, and then 

I do TH t0 ! Cm ' and iS ° ften quick ^ accumulated in one organ, 
an unino wl ' * '* ** inflU6nCe ° f the vital energy which in 

zr r t : k v tnri;? s t the r lk and white from putrefacti °- as 

bidly collected flutT IVTZT^**™*** ""^ " ni0r " 

from putrefaction L ge "e li^h 7"? "'^ " ^^ 
j . . ,7 ln the lmn g body than out of it ; which 

does not arise merely from the exclusion of air, since, when the vital 
powers are low, blood and pus rapidly undergo decomposition even in 
the body.* From all these facts the existence of a force which is often 
vapid in its action, and which moves through space, or of an imponderable 

* Autenrieth, Physiologie, i. 






of this 

matter, is evident; nevertheless we are by no means justified in regard- 
ing it as identical with the known imponderable matters, or general 
physical forces, — caloric, light, and electricity, a comparison which is 
refuted by any close examination. The researches on the so-called 
animal magnetism at first promised to throw some light on this enig- 
matical principle, or imponderable matter. It was thought that, by one 
person laying his hand upon, or passing it along the surface of another 
and by other procedures, remarkable effects were produced, arising from 
the overflow of the animal magnetic fluid ; some indeed have imagined 

t I 

that by certain operations they could produce accumulation 
hypothetic fluid. These tales, however, are a lamentable tissue of false- 
hood, deception, and credulity ; and from them we have only learned 
how incapable most medical men are of instituting an experimental in- 
vestigation, how little idea they have of a logical criticism, which in other 
natural sciences has become a universal method. There is no single 
fact relating to this doctrine which is free from doubt, except the cer- 
tainty of endless deceptions ; and in the practice of medicine there 
is also no fact which can be connected with these wonders, except 
the often repeated, but still unconfirmed accounts of the cure of para- 
lysis by investing the limbs with the bodies of animals just killed, and 
the willingly credited fables of the restoral of youth to the old and 
diseased by their being in the proximity and exposed to the exhalation 
of healthy children, and vice versa. 

We have thus seen that organic bodies consist of matters which pre- 
sent a peculiar combination of their component elements, a combination 
of three, four, or more to form one compound, which is observed only in 
organic bodies, and in them only during life. Organised bodies more- 
over are constituted of organs, — that is, of essential members of one 
whole, — each member having a separate function, and each deriving its 
existence from the whole ; and they not merely consist of these organs, 
but by virtue of an innate power they form them within themselves. 
Life, therefore, is not simply the result of the harmony and reciprocal 
action of these parts ; but is first manifested in a principle or impondera- 
ble matter which is in action in the substance of the germ, enters into 
the composition of the matter of this germ, and imparts to organic com- 
binations properties which cease at death. 

Conditions necessary for the manifestation of life.— Vital stimuli.— -The 
action of the vital or organic force is, however, not independent of cer- 
tain conditions. The necessary elementary combination and the vital 
principle itself may be present, and yet not manifest themselves by the 
phenomena of life. This quiescent state of the vital principle, as it is 
seen in the impregnated germ of the egg before incubation, or in the seed 
of plants before germination, must not be confounded with the state of 

'Cirvv^ir^^ V^ ( 

(CA i 



^ — 



that is 

death; it is also not life, but a specific state of " capability of living." 
Life itself, namely, the manifestation of the organic or vital force, begins 
under the influence of certain necessary conditions : these are warmth, 
atmospheric air, (in ova which are hatched in water, the air diffused 
through the water), and the supply of moist nutritive matters,— 
to say, of nutriment and water; and these conditions do not cease to 
be necessary for the continued manifestation of life. 

The ovum of animals and plants remains in the state of germ only so 
long as it is maintained perfectly quiescent and beyond the influence 
of external agencies: it then remains capable of developement, and retains 
the creative force of the germ, but this force is in a quiescent state. The 
ova of animals will retain for a long period their capability of develope- 

ment, while withdrawn from the influence of the atmosphere. Thus 
the productive power of the germ of the ova of many insects is preserved 
through the winter, and the ova of insects of transatlantic countries are 
batched in the botanic gardens of Europe, an instance of which has fallen 
under my observation. In the same way the germinating power of the 
seeds of many phanerogamic plants is said to be preserved under water 
for twenty years, and in the ground beyond the influence of the atmo- 
spheric air for one hundred years.* Treviranus adduces the observations 
of Van Swieten that the seeds of the mimosa have germinated at the end 
of twenty years, and beans after two hundred years ; and cites another 
observation, according to which an onion taken from the hand of an 
Egyptian mummy, perhaps two thousand years old, had been made to 
grow.f As soon, however, as it is subjected to the external influences 
above mentioned, the germ, when capable of developement, becomes 
developed, or it undergoes putrefaction ; while the already developed or- 
ganism, when the conditions necessary for its further growth fail, either 
falls into a state of apparent death, as in hybernation, or it dies. The 
quiescent vital force of the germ required no external stimuli for the 
maintenance of its passive existence ; but these stimuli are very neces- 
sary for the developed and active life. 

Action of the vital stimuli.— The external conditions which are neces- 
sary to life,— caloric, water, atmospheric air, and nutriment, at the 

time that they maintain life, induce constant changes in the 
composition of the organised body ; themselves combining with the 
body, while certain old components are again decomposed and cast off. 
lhese external agencies have been called vital stimuli; they must, 
however, be carefully distinguished from many other accidental stimuli 
which are not essential to life; and it must always be remember- 
ed, that these vital stimuli produce the phenomena of life by effecting 

* Ann. d. Sc. Nat. t. v. 380. 
+ Treviranus, Erschein. u Gesetz des Organ. Lebens, p. 47. 








material changes, by producing an interchange of ponderable and im- 
ponderable matters. The essential elementary combination of the fluids, 
for example the blood, is by their agency constantly maintained, and the 
blood having suffered the necessary change by the action of the vital sti- 
muli, in its turn stimulates all the organs of the body, — that is, produces 
in them organic changes of composition, essential to the manifestation of 
life, by the interchange of ponderable and imponderable matters, the 
old components of the organs being at the same time in part decom- 
posed and cast off. In animals the nerves also effect important material 
changes in the organs ; and their active force, probably an impondera- 
ble agent, is an important internal vital stimulus. The property of or- 
ganised bodies of suffering constantly, by the action of the vital stimuli, 
certain material modifications necessary to the manifestation of life, has 
been termed incitabilitas, excitability (Reitzbarkeit). The stimuli are 
as it were the external force which sets in motion the wheels of the 
whole machine ; and although the comparison of the animal body with a 
machine may not be very apt, yet the organic principle which in the 
organised body creates the mechanism necessary to life, is incapable of 
activity without this external impulse, and without the constant mate- 
rial changes effected by the aid of the external vital stimuli. Riche- 
rand has, therefore, not unaptly compared the manifestation of life with 
the phenomenon of combustion and flame. The appearance of fire en- 
dures only as long as the combinations and decompositions essential to 
combustion take place ; the oxygen unites with the burning body, 
caloric is developed, and so long as oxygen and the combustible mat- 
r are supplied, the phenomena of fire continue. I am very far from 
making life dependent on combustion ; I merely say, that, in both, cer- 
tain essential combinations and decompositions are constantly going on, 
which in the one produce the phenomena of combustion and light, in 
the other those of life ; that the vital stimuli are for the organised body, 
what the oxygen of the atmosphere and the combustible matter are for 
the phenomena of combustion ; in which case, however, the oxygen is 
not called the stimulus of the flame : and I further say, that the name 
stimulus, vital stimulus, gives an empty and indeed false notion, un- 
less the material changes, — the constant new combinations and decom- 
position of ponderable and imponderable matters — induced by it be 
at the same time remembered. It is, however, necessary always to 
recollect, that in the material changes effected by the vital stimuli, 
although inorganic substances come into play in them, binary com- 
pounds are not generated for the organism, but only cast off as the 
result of the decomposition of the old matter ; such a product is carbonic 
acid : while the oxygen, which in the process of respiration partly enters 
into combination with the blood, produces a certain change in this 

fluid, which in its turn must produce in the organs endowed with the 

1Hvl^7 %^ \j\ 




• — 


"M € 

\ A ^vU^j 






vital principle, material changes very different from those that would 

be exnected in a. d«»ad hnAir 



be expected in a dead body. 

These general essentials o. «*, M1C vllul summt) or re novatmg (mte- 
gnrende) stimuli, are common to plants and animals : for plants, light 
■ also an i ndispensab le vivifying stimulus ; for animals, although the 
want of its influence renders the body scrofulous and rickety, it is not 
immediately necessary, as is proved by the life of many animals, particu- 
larly the entozoa, and its absence is only so far injurious as it modifies the 
other essential vital stimuli. As an essential for animal life must be 
recko ne a not merely the assumption of new matter, but more especially of 
ma er already organised; while plants take upas nutriment organised 
matters partly converted into binary compounds, and change ^binary 
mto ternary compound, The necessity of new matter, caloric, water* 

and atmospheric air for the development, subsistence, and growth of 
organised bodies, is quite indispensable. 
A great error has been committed in l 

othpv cfl™ r i-i i c«««»«*g me vivijyirtg stimuli with 

n c Z ' J ? d ° " 0t eSSentia11 ^ enter int0 the composition of orga- 

nic r*<? ,° n0t reMVate * eir P° wers - A "echanical stimulus, 

for eta m °f 6 C ° n,liti0n ° f 8 memWe e " dOT ™ d «* — *%. 

but doeTuo't PK T'T eXCitCS ' U " tme ' a Vilal P^omenon-sensaL, 

contrarv T "',■ ,"• f ^"'^ the ° rganic forees ' " hiIe > « *e 

the o™ eSSent,a i, v ' tal «*»"* "ally contribute to the formation of 

tlie organic matter. The nutrimpnt in ^ « * i • »■***»« 

mulus of th« ~ • t , WMmwe ^» ln "»e first place, is not merely a sti- 

searcely dispense with food for loneer thaT',, I u 7 *' Ca " 
seouences , the higher brutes do XZ^^Z^ Z 

tdes, on the contrary, have been known to fast f„ r m „„ ths !! hi 7" 
be en ch.efly observed in serpents and tortoises. Water, Uethe it 

comb ne e ; ^l ^f^"— >. " •"» absolutely essential in its un- 
less thlv. mamfestafon of life, since the animal tissues, un- 

so esTenL" f : T T ' "" ^P* 16 ° f »*» ^'- * 

higher an^Y / mamfeStat! ° n ° f «"» "tal phenomena, that in the 
out the'Tnt t ,T S J? S J Ub8iSt a m0MCnt With0ut aspiration, with- 
influence „f Xd " ctf ° ^"^ * ^P™"""' "* " ith » ut * e 

and the a S sum P U„ n of ""/ ° P ° n ?' ° rga " S - T bo supply of nutriment, 
be .uspended C a co„ alir:- ft0m *! "T" '"'" tha OT « a " s > -X 
other change, which ZtZlCXZT " u V" ' ^ ** 

tion m »t,j l, t. be or gans by virtue of its aera- 

man onty for few _ ^ ., ^ ^ 

at the tune when the animal system is itself yet unable to generate anv 
"eat, but ,s mdispensable for all organic beings, plants and animal'seel 

this has 



r ^^p 





also to enter into the composition of the organic system. For the organic 
processes require in every animal and plant a certain temperature ; and it 
is also known, that in chemical processes among binary compounds, while 
a certain temperature is required, a determinate quantity of caloric be- 
comes latent, or is absorbed for the formation of new compounds. Under 
the influence of the vital stimuli, — nutriment, water, air and caloric, — the 
organic being is developed spontaneously from the germ, while the organic 
matter present in it is constantly undergoing decomposition, and the phe- 
nomena of life are themselves the results of the constant union of new 
and the separation of old elements of the organised matter. Whether 
electricity also is necessary to the developement of life is at present quite 

There is, however, an evident difference in the degree in which living 
beings are dependent on different vital stimuli. M. Edwards has observed, 
that newly-born warm-blooded animals have most need of external 
warmth, and without it cannot live ; while they can live under water, 
without breathing, much longer than adult animals. The time that they 
can remain in the water is longer in proportion as the temperature of 
the water rises from 32° to 68° Fahr. ; remains the same when the 
water is between 68° and 86° Fahr. ; and becomes shorter between 86° 
and 104° Fahr.* The adult animal has, according to the vital relations of 
its species and genus, a certain temperature, and consequently a certain 
geographical tract, assigned to it in which to live. 

The duration of irritability without the application of the vital stimuli, 
is generally in the inverse ratio of the perfection of the organisation. 
The simplest animals can longest dispense with these stimuli. Mol- 
lusca and insects, as well as the scorpion, have been kept for months 
without food f Serpents and tortoises also live for months without food, 
while man in the healthy state can scarcely survive a week. Several 
insects will live for days in mephitic gases ; the larvae of the cestrus, for 
example, according to the experiments of Van der Kolk, live for a long 
period in irrespirable gases. Molluscous animals have been kept during 
24 hours under the air-pump. Reptiles live a very long time without 
respiring; in water deprived of its air some few hours, according to Spal- 
anzani and Edwards, and in water still containing air, from 10 to 20 
hours : frogs, the lungs of which I had extirpated, lived 30 hours. The 
numerous accounts, however, of toads, &c. having been found living in 
blocks of marble, and in trees, are to be regarded as instances of decep- 
tion and credulity, although Herissaut and Edwards kept reptiles alive 
for some little time enclosed in gypsum. But Edwards is convinced 
that gypsum is permeable to atmospheric air ; when the reptiles were 

* Edwards, De Tinfluence des agens physiques sur la vie. Froriep's Notiz. 150, 151. 
See also Legallois, Exper. sur le principe de la vie. 

i* See my paper on the Scorpion, in Meckel's Archiv. 1828. 






und™,- • \/ OTSUm a " d merCUry ' the ^ dicd » 1» ic % » ^ 

Z state tA , 8reater C ° m P licati ™ of *e organisation increases 

mals there* d . el>e, : dence f the ^ans on eaoh other. Simple ani- 

Eeviva, frl f h " . "^ "*" ^ "^ " ,an a " imaIs hi 8 h « ! " th " -ale. 

an m >s Sua T IS*""" ^ <* """* "> OTe eas * ia *• '°«r 

ftred de.ioo^ am "" r'^ ^ wheel - a " ! ™leole S> which had snf- 
wa er Eh'T' T 0VCT the a P? earan - "I* »n being moistened with 

Bauer hale 11^ ST"' f ' ^ "* ° 0Uld ° CCUr " Sleinbuch » d 

eased ll, ?T^ "^ ** Wkh "** *> the " bri °«os of dis- 

presen, signs o f ,ifie f or a^mtf^heZ ^^ 

n the muscles and nerves of these animals is well known. The <Z ? f 
hfe continue for a longer period in young animals also, probab v fn ac 

abTi s I h gre8ter f mpliCity ° f th6ir StrUCtUre - Ia *• «*■£ f 
rabbits, I have seen the muscular irritability continue longer after death 

made stf ! 1 T '• ^ ^^ °" this P™ 1 - I -8-"'* *- 

"frabb^ b 6 '"? eXpenme,Us ' tha "•■* of which is, that on Idli- 
ng rabbits by immersion in water, excision of the heart, or opening the 

thorax on the first fifth, tenth, and so on every fifth day until tlfe thbtie h 
day after birth ft ,s found that the duration of sensibility is less every 

lation after the spina, cord was Z „y d t/STK? *l *"? 
these facts are fuHy explained by the l£ '£££?£« £ 

upon the other. 


Organised bodies are subject to death. 

^4 of fh^^ ptTa."" ^ ma,S M PlantS ' beC ° maS exti -> a - aa 




m a stream from rtl j • ^y^^jarce nows, as it were, 

while the „,d ""a * e JSJ *?^ int °, ** «« "ew.y Placed, 
" Those organist bodi 6 ; .^ " "'" deScHbed ^ Autenrieth : 

roots,-as fhe «S "t W ," "!** ^'^ **« *«" 

rees, bv nTeafst" It l!™?*' b 7 means of runner, ; or, as 

s c r th b c ::^f zf i b ™ d - 7 do Mt dfe - ia * 

individual, at the same Letht ft [s a ne^r* a Tf- ^ ° W 

even in ,h„, „u„.. .!,„ „,j s « new and independent betng. But 



' ^-rf^.. 


* Edwards, in Meckel's Archiv. iii. p. 6I7. 




. : 




continues active only in the new offset, which in its turn orf^B^ 
extend itself on the one side, while it dies on the other. 


takes place connectedly,— namely, the decay on the one side, and the for- 
mation of a new living body on the other,— is effected in an interrupted 
manner in man and the more perfect animals. The young is separated 
from the parent as a new living body, before the old being perishes ; 
and the original individual dies, while the species seems to be im- 




It would not be 

force is transferred from the producing parts of organic beings to the 
young livhig^roducts, while the old producing parts perish, is one of the 
most difficult problems of general physiology. We can ' x ~~ 
can only describe the phenomena in their connection, 
sufficient to say that inorganic influences gradually destroy life ; for in 
that case the vital force would begin to diminish from the very com- 
mencement of existence ; and it is well known that at the time of virility 

the vital force is in such a state of perfection that it multiplies itself by 
the formation of germs. There must then be some other more occult 
cause, which induces the death of the individuals, while it ensures the 
propagation of the vital force from one individual to another, and in 
this way secures it from perishing. It might be asserted that the in- 
creasing fragility of organic bodies in old age arises from the increasing 
accumulation in them of certain products of the decomposition of the 
organic substance, the chemical affinity of which matters at last balances 
the vital or organic force ; but in that case, also, the vital force must 
diminish from the very commencement of life ; and there is besides no 
proof of such accumulation taking place. All that can be done, ^eforej 
is to show the connection of these phenomena with developement. 
o-erm of an organic being is compared with its state in extreme age, it is 

£3 **^ .__ — r — «■ « ^ 1 • ■ "¥"7"" 

If the 

seen that, at the latter period, the whole, on which, according to Kant, 
the existence of the individual parts depends, subsists almost solely by 
the reciprocal action of the individual parts and of their forces, like the 
working of a piece of machinery, which is maintained solely by the reci- 
procal action of the parts of the machine on each other ; in the germ, on 
the contrary, the force, in which is seated the producing cause of all the 
parts of the future body, is still undivided. The organic principle in the 
o-erm is, as it were, in the state of the greatest concentration. The capabi- 
lity of developement is at its highest degree, developement itself at its 
lowest. When the operation of this principle has endured for a certain 
time when the period of youth is passed, this state of simplicity, in which 
the whole force is undivided, no longer exists ; there is then a state of 
complication, in which the force is divided among the different parts. 

* Autenrieth, Physiol, i. 112. 



But the more the single organic force of the body becomes divided, and 
the less of this force remains unapplied, so much the more does the 
organism seem to lose the property of becoming vivified by the influence 
of the general vital stimuli ; and the less strong becomes, as it were, the 
affinity between the organised substance and the stimuli, which seem 
to nourish the flame of life. Therefore, when developement is complete, 
if the immortality of the vital force is to be secured, the formation of a 
germ is necessary. The germ, containing the vital principle in an un- 
divided state, also possesses the greatest affinity for the vital stimuli, 
and this affinity again diminishes in proportion as the organism is deve- 
loped. This has the appearance of explaining the phenomena, but is in 
reality merely a statement of their connection, and it is not even certain 
that the statement is correct. 

Why organic matter perishes.— The cause of the constant destruction 
of the matter of organic bodies during life, and of the necessity for its 
being replaced by new organic matter, is the second point to be investi- 
gated. In plants this change of material is less remarkable, and is 
seen, to a great extent at least, only in the gradual death of the old 
leaves : in plants, as Tiedemann remarks, what is once formed, is for a 
long time subject to no change of material, but retains, for a certain 
period, its first composition. In animals, on the contrary, there is a 
constant, renewal of the component matter. This difference between 
animals and plants, Tiedemann explains, by supposing that in animals 
there are certain functions, the performance of which induce changes in 
the material composition of the organs, as seems to be the case in the 
action of the nerves. # 

M. SniadecMs theory.— M. Sniadecki, who has endeavoured to solve 
this problem, t calls the substances which are capable of nourishing or- 
ganised bodies, matters susceptible of animation. The susceptibility of 
animation with which these matters are endowed, is however quite 
general ; they are capable of taking any form as long as they are not 
subjected to special influences, and for that reason are without special 
form. Organic matter then has, as M. Sniadecki expresses it, a general 
tendency to life and organisation. But as soon as any part of it comes 
withm the influence of any individual being, the vital force of the indi- 
vidual gives a special direction to this general tendency; hence the in- 
dividual and local conformation, and the different modes of life. Every 
special form of organisation is thus, according to M. Sniadecki, the result 
of two tendencies ; one general, which resides in the matter itself, and by 
virtue of which certain substances strive towards life and organisation 
generally; and a second special tendency, which exists in the individual, 
and this latter determines the mode in which the life shall be manifested, 

* Physiol, i. p. 376. 

■f Theorie der organischen Wesen, aus dem Polnischen. N'urnberg, 1821. 

n 2 






and the form in which the organisation shall be effected. This particle 
of vivifiable matter, therefore, which has been subjected wholly or in 
part to the influence of the vital principle of a certain individual,, has 
acquired a proportional degree of vitality ; but, as it has not ceased to 
be susceptible of life, it must, in virtue of this susceptibility, still tend 
towards further life, and to the assumption of all the other forms of 
organisation, — that which it already possesses being alone excepted. If 
this particle of matter is now compared with the organic matter, which 
is as yet quite unorganised, and which has an equal tendency to assume 
all forms, it is evident that it must possess less susceptibility of life than 
the latter. The diminution of its susceptibility of animation must be 
commensurate with the tendency which it had to take the particular form 
in which it exists, this tendency being already satisfied. 

From this reasoning M. Sniadecki concludes, that the capacity of the 
matter in organised individuals for life, is in the inverse ratio of the 
vital force to which it has already been subjected ; or, in other words, 
the matter which is taken into organised bodies loses just as much of its 
capacity for life as it gains of individual power ; consequently, in the 
same proportion as it assumes a given form, it loses its faculty of assum- 
ing that form. As soon, then, as it is completely organised, and has 
undergone the whole vivifying power of the individual, it loses all suscep- 
tibility of organisation in reference to this individual. The vital force 
of the individual then loses all power over it; and this matter will, in 
the midst of the living body, be incapable of living and inert, and con- 
sequently only fit to be discharged from the body. In this way Snia- 
decki explains the constant change of organisable matters in organised 


If this explanation is adopted, the general processes in organised 
bodies can certainly be further explained, as has been done by M. Snia- 
decki with admirable simplicity and clearness. Strong objections, how- 
ever, may be urged against it. According tc 
only essential part of organised bodies is, not the organised matter, but 
the organic force. The force manifests itself as long as its organising 
action is continued ; that is, as long as matter susceptible of organisa- 
tion is present: the organised matter itself possesses no organic force, 
and is excreted from the body as being useless. But, according to this 
view, the excrementitious matters ought to bear the character of com- 
plete organisation, and should be susceptible of immediate organisation 
by other beings. This is not the case. The excrementitious matters 
of most general occurrence are the urine, and the carbonic acid which 
is exhaled in respiration. But these substances are not susceptible of 
organisation by other animals ; they are the products of the decomposi- 

tion of animal matters. 

Author's views.— It is much more consonant with facts to suppose that 




the matter assimilated by an organised body becomes endowed with the 
organising power at the moment that it is organised. The organising force 
itself is in many simple organic beings divisible, by division of the organised 
matter. We are thus led to the very opposite conclusion to that of 
M. Sniadecki. He maintains that the matter loses its capacity for life 
in proportion as it is endowed with life. We say, matter becomes vivi- 
fied in proportion as it has experienced the vivifying force ; it acquires 
the power of imparting life to other matter in proportion as it is 
itself vivified ; and it exercises this power while acted on by certain 
vital stimuli, which, while they unite with the organised tissues, cause 
the separation and excretion of other substances. Certain vital stimuli 
entering the blood, as in the process of respiration, and then exerting 

their influence on the organised tissues, cause the affinity between certain 
elements of the organised matter and the blood to become greater than 
that between the different elements of the organised matter itself. The 
vivification of the organised matter by the vital stimuli, in a manner which 
is attended with excretion, renders it capable of receiving nutriment ; but, 
in proportion as a portion of matter has life imparted to it, it acquires 
the faculty of giving life and organisation to other matters : it does not 
become excrementitious ; on the contrary, it participates in the organis- 
ing force of the original body. 

The cause why organic substances are being constantly decomposed 
and cast off from the animal body, might at first sight be thought to lie 
in the following circumstance : — In the conversion of the food into 
matters proper for the nutrition of the body, some substances, from 
containing an excess of useless elements, may be necessarily ejected 
again. Thus plants, in forming ternary vegetable compounds from car- 
bonic acid and water, give out the superfluous oxygen. In animals the 


only excrementitious matters of any consequence, which are quite 


useless in the organic system, are the carbonic acid and the urine. 
The excretions of animals, it is true, nearly equal in quantity the 
matter taken into the body; but in part they are purely useless excreta: 
many are destined for particular purposes, or are evacuated acciden- 
tally, as the mucus of the intestines, and perhaps also the bile. The 
faeces consist partly of substances taken as food ; whereas the urine 
and carbonic acid are separated from organised tissues, and are per- 
fectly useless to the system. The urine certainly varies in its compo- 
sition according to the nature of the food, and therefore evidently con- 
tains also useless components of the yet unorganised food. But the 
composition of the urine remains unaltered in animals which live without 
food even for months, as many reptiles, serpents, and tortoises will do. 
The urine, therefore, it is certain, must be a means of carrying out of the 
system parts of the organised components which have become useless; and 
it is evident that the vital actions themselves are attended with decomposi- 





tion of organic matter. Thus even the pupse of insects at the period of 
their transformation, when they take no nourishment, afford excremen- 





he embryo of the higher animals, also, forms a peculiar excretion by 



It is remarkable, also, that urea and lithic acid are excreted by many 
invertebrate animals as well as by the vertebrate ; thus insects, as we 
have said, secrete lithic acid by the Malpighian vessels, and M. Jacob- 
son has discovered lithic acid in a special excretory organ in molluscous 
animals. We have not the most distant conception of the cause which 
renders the reciprocal action of the atmospheric air with the living body 
so necessary to life ; but the hypothesis that respiration supplies the ele- 
ments still required for the formation of animal matter, or removes the 
elements superfluous to this compound, is refuted by the facts that most 
animals take the animal matter ready formed, and that reptiles continue 
to respire, to consume the oxygen of the air, and to exhale carbonic 
acid, when they take no food for months. 

The excretions which are being constantly formed by the vital process 


Carbonic acid is 

a binary compound formed by the decomposition of animal matter : urea 
is very analogous to a binary compound, and is perhaps really one ; at 
all events, Woehler has shown that it is produced from cyanite of 
ammonia with extreme ease. As these excretions are constant, even 
when the supply of nutriment is stopped, it necessarily follows that a 
constant decomposition of the substance of the body is essentially con- 
nected with life. It cannot indeed be otherwise, if it be true, as it has 
already been proved to be, that the vital force is manifested in an animal 
only while certain vital stimuli produce in the living tissues constant 
material changes, of which the phenomena of life are merely the exter- 
nal signs, just as flame is the appearance resulting from the material 
changes effected in combustion. The impulse to these material changes 
is given by respiration ; the blood, undergoing a constant change by 
respiratory process, again effects constant material changes in the organs 
to which it is distributed : from the former components of the tissues 
are formed the general products of decomposition,-carbonic acid, and 
the substances so rich in nitrogen which are found in the urine, urea and 
lithic actd;— and this decomposition of the materials of the body, which 
constantly attends the vital process, in its turn renders necessary the 
supply of new nutritive matters, which are subjected to the organising 
force. An organised part presents vital phenomena, and organises new 
matter, only while excited by the constant exertion of organic affinity 




between the blood and the components of the tissues ; by the exertion of 
which affinit}' certain components of the organs are decomposed, their 
place being again supplied by new nutritive matter acted on by the or- 

ganic force. 


The nutriment of animals consists of 

organic matters, animal and vegetable ; the nutriment of plants consists 
partly of vegetable and animal matters not wholly decomposed, and 
partly of binary compounds, namely, carbonic acid and water. It has been 
imagined that plants can nourish themselves from carbonic acid and water 
alone ; the experiments of Hassenfratz, M. de Saussure, Giobert, and 
Link, have proved however that plants under these circumstances if 
they grow at all, do so very imperfectly, and seldom flower and bear fruit.* 
It appears, therefore, that it is only when they are at the same time 
nourished by organic compounds in solution, which have not wholly 
undergone decomposition, that plants generate organic matter from 
binary compounds. 

The power of generating organic from mineral compounds cannot, 
however, be entirely denied to plants ; for, were it not for this power, 
the vegetable and animal kingdoms would soon perish. The unceas- 
ing destruction of organic bodies presupposes the formation by plants 

of new organic matter from binary compounds and elementary sub- 

The wgmti&foz ce also is increased during the organisatio7i of 
Now, by the growth and propagation of organised bodies, the organic 
force seems to be multiplied ; for from one being many others are pro- 
duced, and from these in their turn many more ; while, on the other hand 
with the death of organised bodies the organic force also 
perish. But the organic force is not merely transmitted, as it were, from 
one individual to another, — on the contrary, a plant, after producing 
yearly the germs of very many productive individuals, may still remain 
capable of the same production, — the source of the increase of the organic 
or vital force seems therefore also to lie in the organisation of new matter ; 
and, this being admitted, it must be allowed that plants, while they 
form new organic matter from inorganic substances under the influence 
ot light and caloric, are also endowed with the power of increasing the 
organic force from unknown external sources, while animals also in their 
turn would generate the organic force from their nutriment under the 
influence of the vital stimuli, and distribute it to the germs during propa- 
gation. Whether during life the organic force, as well as the organic 
matter, is constantly suffering destruction, is quite unknown. Thus much 
however seems certain, that, at the death of organic bodies, the vital 
force is resolved into its general natural causes, from which it appears 
to be generated anew by plants. If this increase of the vital principle 

* Tiedemann's Physiolog. i. 218. Translation, p. 83. 

seems to 






in existing organised bodies from unknown sources in the external world 
be not admitted, it must be supposed that the apparently endless mul- 
tiplication of the vital force in the process of growth and in propagation 
is merely an evolution of germs encased one within another, or it must 
be admitted that the division of the organic force which takes place in 
propagation does not weaken its intensity ; a supposition which appears 
absurd. But the fact would still remain, that, by the death of organised 
bodies, organic force is constantly becoming inert, or resolved into its 
general physical causes, 

8. Of the Organism and Life of Animals. 

Differences of plants 

Developement, growth, excita- 

bility, propagation, and decay, are the general phenomena and pro- 
perties of all organised bodies, and are the results of organisation ; but 
there are other properties peculiar to animals, which may therefore 
be termed animal in contradistinction to the general organic proper- 
ties. Sensation and voluntary motion are the more remarkable animal 

Motions of plants. — Plants, it is true, are not wholly without motion, 
for their organisation is attended with internal motions, namely, the cir- 
culation of the sap; moreover, they turn spontaneously towards th 
light, their roots extend in the direction of the most nutritious soil : 
some plants climb along the surface of bodies which offer them means 
of attachment, and their stamens incline towards the pistil at the time 
of impregnation ; many plants indeed, particularly those of the genus 
mimosa, possess in their leafstalks a power of motion which can be ex- 
cited by various irritants, whether mechanical, galvanic, or chemical 
such as alcohol, mineral acids, aether, and ammonia, — as well as by change 
of temperature or light; thus affording another instance of the general law, 
that the specific excitable properties of organic bodies do not vary in 
the mode of their manifestation according to the nature of the stimulus 
which excites them, but are manifested each in its peculiar manner on 
the application of the most different stimuli.* Lastly, in the hedysa- 
rum gyrans there is, besides the general influence of light on the motion 
of the larger middle leaflet, an incessant rising and falling of the two 
lateral leaflets, independent of external stimuli ; and some of the lower 
vegetables— the oscillatoria, for example,— present a constant vibratory 
motion. The twining of certain plants is supposed by Palmf to be de- 
pendent on their mode of growth causing the extremity of the branches 
to describe circles, thus enabling them to lay hold on near objects : but, 
however this may be, the fact that the cuscuta twines only around 
living plants, seems to show that, in it, this motion is in some measure 


Treviranus, Biologie, v. 201. 229. 

f Palm uber das Winden der Pflanzen, p. 48. 




dependent on organic attraction; and the motions of stamens and 
leafstalks have too much resemblance to the irritability of muscles, not 
to be compared with it. Dutrochet* has discovered, that in the mimosa 
the irritability resides in the cortical part of a swelling situated at the 
articulation of the leafstalks. When this swelling, which exists in those 
mimosse only which possess this irritability, was removed, no motion could 
be excited; when the upper half only was cut away, the leaf was elevated 
but not depressed again. Hence Dutrochet infers that the elevation 
and depression of the leaf and leaflets arise from incurvation of the 
opposite sides of the swelling ; elevation being produced by the lower 
part of the swelling becoming convex, depression by a similar incurva- 
tion of the upper part. Slices taken from the cortical part of either 
the upper or under half of the swelling, when placed in water, are seen 

to become curved. Other physiologists, Lindsay, Hitter, and Mayo, have 

observed a change of colour at the time of the movement, so that the 

phenomena might be attributed to an afflux of sap to either side of the 

Motions of animals — There are then, in plants, organs which, by their 
motions, resemble either the muscles or the erectile parts of animals ; 
but there is this difference, that the motions of animals are not merely 
the result of the action of a stimulus on irritable parts, but are produced 
by the internal operation of parts not endowed with motion, namely, the ' 
nerves, on those which have motion. Dutrochet, it is true, has ob- 
served that, when he directed the focus of a burning-glass on a single 
leaf of the mimosa, the impression was propagated gradually to the other 
leaves ; and he considers the false trachea?, or ducts, to be the organs 
which transmit this influence. But, as Treviranus justly remarks, this 
is merely an hypothesis ; for other observers have perceived only the 
local effect of concentrated light, and, besides, the shock produced by 

the local motion may be sufficient to excite motions throughout the 
whole plant. 

Another remarkable character of a part of the motions of animals is, 
that they are excited, not merely in accordance with the harmonious action 
of the whole organism, but by the voluntary operation of a single organ,] 
namely, the organ of the mental faculties. These motions are voluntary.' 
J ratability again must not be confounded with sensibility. Plants are 
irritable, but not sensible ; the muscles also when separated from the 
animal body are still irritable, but they are not sensible. Plants cannot 
be affirmed to possess sensibility, unless they manifest consciousness, 
amfestations of sensation and voluntary motion are the sole charac- 
eristic mark of the simplest animals. Compound animals have often a 

itecnerches Anat. et Physiol, sur la structure intime des animaux et des vegetaux. 

t Tiedemann's Physiologie, i. 623. G. R. Treviranus, Ersclieinungen und Gesetze 
des organ. Lebens. 



















- ^ 






ramified and vegetable form, and are fixed by a stem to the ground ; the 
individual faculties of the single polypes,— the voluntary motion of each 





movements of infusoria are free and voluntary. If, therefore, it is still a 
matter of doubt whether certain simple organised beings, such as the 
sponges and several so called alcyonia, are animal or vegetable, the absence 
of all voluntary motion in these bodies, whether of the whole or of indivi- 
dual parts of it, must determine the question, and they must more properly 
be numbered among the vegetable marine structures. It may certainly 
be said that the embryo of sponges, as Dr. Grant* has shown, like the 
embryo of polypes and corals, moves by means of cilia ; but the distinc- 
tive marks between the embryo of sponges and marine infusoria are 
by no means certain, and similar motions have been many times observed 

in the embryo of true vegetables, 

+ Th 

movements of the ova of zoophytes by means of cilia, are not to be 
regarded as voluntary ; the vibrations of cilia on the branchiae of some 
of the lower animals are a similar phenomenon. It would appear from 
the researches of Nitzsch^:, that some vegetable and animal products of 
infusions are very closely allied to each other. Thus the bacillaria 
pectinalis, and other species of this genus, would seem to have completely 
the characters of plants ; while other species again have the characters 
of animals. Ehrenberg, however, seems not to admit the existence of 
such a relation between the two kingdoms; he remarks also that the 
active movements of algae should not be regarded as proofs of animal 
life, for he has never seen the moving sporules of algae take the slightest 

solid nutriment ; and thus, according to M. Ehrenberg, the algae scattering 
their ova or sporules differ from monads, as a tree differs from a bird. 

* Edinb. Philos. Journ. vol. xiii. p. 382. 

<t This has been observed by Trentepoil with respect to the conferva dilatata, £, 
Roth, or ectosperma clavata, Vauch., and by (jr. R. Treviranus with respect to the* 
conferva limosa, Dillw. See Treviranus, Biologie, t. iv. p. 634. Recently Unger has 
repeated these observations, in watching all the transformations in the conferva dilatata; 
and it appears, as Treviranus also maintains in opposition to Vaucher's supposition 
that the presence of infusoria had given rise to error, that these originally moving 
gemmules are again converted into algae from which they were produced. See Unger 
in Nova Act. Acad. Nat. Cur. t. xiii. p. 2, p. 789, and Treviranus in the Biologie, t. iv. 
and in Erschein. und Gesetz. des organ. Lebens, p. 51 and 183. This motion of the 
embryo of vegetables is also instanced in the Zoocarp6es of Bory St. Vincent, which, 
themselves jointed threads, emit germinal granules, which move about like infusoria, 
and then again assume the vegetable form ; these he places together with the whole 
tribe of arthrodi6es, in a class intermediate between the animal and vegetable king- 


± Beitra^e zur infusorienkunde. 
Poggendorfs Annal. 1832. 1. 

Halle, 1817. 





opinion ; he remarks, that the motions of these germinal granules cannot 
be regarded as an animal act, although it appears more wonderful than 

the regular motions of some of the lower vegetables, namely, the 

Animals have a nervous system — The sensations and other incitements 
to voluntary motion, — the true animal functions, in fact, — are dependent on 
the nervous system. The organs of animals manifest as great a depend- 
ence on the nerves as the plants on light. Nerves were known to exist in, 
all vertebrate animals, but they had been discovered in a part only of 
the invertebrata ; and the opinion was very general, that the lower 
animals have no nerves, all the functions of sensation, motion, and di- 
gestion being performed by the same particles of their simple substance. 
The great divisibility of the lower animals seemed indeed to justify, in 
some measure, this conclusion. The nerves were not known to exist in 
the infusoria, polypifera, acalepha, and most of the entozoa. But Otto had 
already described the nervous system of the strongylus gigas, a worm of 
the kidney. In the round worm, the nervous cord between the two 
vascular trunks is very evident. Mehlis has described the nervous 
system of the d.stoma hepaticum, Nordmann that of the pentastoma 
and diplozoa. There is no doubt but it exists in all the intestinal worms, 
liedernann discovered the nervous system of the echinodermata; at least, 
that of the asterias. Lastly, Ehrenberg* has shewn the existence of a 
complex structure in the lowest animals, the infusoria. In the simplest 
mfusory animalcules Ehrenberg has discovered a mouth and compound 
stomach ; in others, mouth, intestine, and arms. In the more perfect 
rototona, and in some infusoria, Ehrenberg has even described, and re 
presented very distinctly, a kind of teeth in the mouth, male and female 
organs of generation, muscles, ligaments, a trace of vessels and nerves 
and eye-points. These points, which Ehrenberg believes to be real 
eyes, are of especial importance for the question of the existence of a 
nervous system in the simplest animals. On the head of planari*, in which 
no nervous system has hitherto been discovered, exactly the same eye- 
ots have been seen as exist in many annelides, which are known to 
thTe n 7 VOUS /^' Stem ' from whi <* circumstance, and from the fact that 
ont,V n! r" 16 nereides are rea % formed of an enlargement of the 

tha 2 l' a CUP " 1Ike C0V6rin S of black Fg»ent, * » very probable 

that the plananae also, and indeed all the lower animals which have 

c 1 eye-dots, really possess optic nerves, and consequently a nervous 

system.t It becomes indeed more and more probable that all animals, 

* Organisation der Infusionsthierchen. Berlin, 1830. 
tW H Gl ' uithuisen beli eves that every dark spot of the skin has a certain relation to 
e unction of vision, his reasoning is quite inexact ; for the first condition for vision 

1 1 



without distinction, have a nervous system. The difficulty of distinguishing 
the nerves of the asterias, and of several mollusca, teaches us that we must 
not attribute too much importance to the fact that even in larger animals, 
such as the actinia and medusa, there are no distinct traces of this 
system. [Ehrenbergf has recently discovered a nervous system in the 
medusae, with red points, which he believes to be eyes.] 

Digestive apparatus. — Animals are distinguished from plants, however, 
not merely by sensation and voluntary motion. These attributes neces- 
sarily modify the other functions which animals possess in common with 
plants. This is very beautifully set forth by Cuvier. Vegetables, fixed 
to the surface on which they grow, absorb immediately, by their roots, 
the nutritive particles of the fluids which permeate them ; animals, on 
the contrary, which generally are not fixed to one spot, but either wholly 
change their situation, or at least, as polypes of a solid stem, seize their 
food, must have the means of carrying about with them the store of fluids 
necessary for their nutrition. By far the greater number have an internal 
cavity, into which they introduce the matters intended for their nourish- 
ment, and in the parietes of which arise the absorbent vessels, which, as 
Boerhaave aptly remarked, are true internal roots. \ In some animals 
there is no anus, in others the existence of an intestine is doubtful. 
Nevertheless Mehlis states, in opposition to the common belief, that in 
the taenia there is a vessel-like intestine, commencing at the narrow oral 
orifice and soon becoming bifurcated. A well-known narrow bifurcated 


canal in the echinorhynchus is supposed to be the intestine. There is 
another cause than that above mentioned, for the necessity of a special 
cavity for the first process of assimilation in animals; the food of animals 

requires to be dissolved. The nutriment of plants is already in solution, 
and consists partly of water holding carbonic acid in solution, and partly 
of the dissolved organic matters of the soil, humus. The food of animals, 
consisting of compounds already organised, requires to be prepared, com- 
minuted, and dissolved ; hence digestion is a preparatory assimilation of 
the food, peculiar to animals. 

The circulation in plants is much more simple than in animals, and is 
in no case provided with a special organ for the distribution of the 


is, that the optic nerve shall have a special sensibility for light, and not be a mere nerve 
of sensation. Those lower animals which, without having eyes, are sensible of the 
influence of light, can be so only by reason of the warmth accompanying the light. 
Hence the annelides,— for example, some nereides,— without having a transparent optic 
apparatus for distinguishing different objects, nevertheless have nerves for the mere 
general perception of light and darkness ; and the mere existence of optic nerves for the 
general perception of light in an animal which, from the absence of optic apparatus, 
can distinguish no definite object, is a strong proof that the perception of light is always 
connected with special nerves. See my Observations on the structure of the eye of the 
Nereides. — Annal. des Sciences Nat. t. xxii. p. 19. 

w » 

t Miiller's Archiv. 1834, p. 571. X Cuvier, Anatomie Compared, t. i. 





fluid, namely, a heart. In some simple plants there is a rotatory motion 
of the sap in the interior of internodia and in cells. Corti discovered 
this motion in the chara, and his observation has been confirmed by 
Fontana, by G. R. and L. C. Treviranus, Amici, C. H. Schultz, Agardh, 
and Raspail ; Meyen has discovered a similar motion in the cells of the 
vallisneria spiralis, and in the hairs of the radicle fibres of hydrocharis 
morsus ranae. In the higher vascular plants Professor Schultz* has 


discovered a continuous motion of the sap, which according to Schultz, 
is a true circulation, ascending in one vessel, and descending in the 
other ; the two streams, however, communicating by cross branches 
between the different vessels. In fine sections of the leafstalk of many 
plants it may also be distinctly observed that the course of the sap is 
different in different vessels ; and this I have seen very distinctly even 
in fine sections of the leafstalk of fig-leaves. Whether the section 
whether the division of the vessels, has not some share in determining 
the direction of the currents, can be ascertained only by observing 
the different currents in uninjured leaves. In leaves of the chelido- 
nium which were . still in connection with the living stem, I have cer- 
tainly seen currents in opposite directions. The circumstance observed 
by Dutrochet, that an ascending and descending rotatory motion is 
produced in a perpendicular thin glass vessel filled with water, when it 
is heated differently at different parts, cannot be applied to explain the 
motion of the sap in plants ; for in that case the sole cause of the 
rotatory motion is the ascent of the heated and expanded molecules of 
water. It appears, therefore, that the motion of the sap in plants is 
effected, in some manner at present not understood, by attraction and 
repulsion, exerted in the leaves on the one hand, and in the roots on the 
other. It is certain, however, that light exerts an attraction upon the 
sap, since it evidently determines the growth of the whole plant. 

The circulation in animals, on the contrary, derives its impelling force, 
not from external influences, but from the contraction of a central 
organ, the heart. It is still uncertain whether a perfect circulation is 
an absolute predicate of animals; at all events, in many simple animals 
neither heart nor vessels have at present been discovered. 

he respiration of animals and plants affords a very important dis- 
ve character. In plants, and in the most simple animals, respiration 

p oimed by the entire surface ; but in the more perfect animals the 
surface is not sufficient for the necessary aeration of the fluids, and an 

gan is required, which in a small space shall afford an immense super- 
ficies for contact with the atmosphere. But the products of respiration in 
the vegetable and the animal kingdom are also different. In plants the 

Ueber den Kreislauf des Saftes im Schollkraut. Berlin, 1822.— Die Natur der 
lebendigen Pflanze. Berlin, 1823.— Annal. des Sc. Nat. t. xxii. p. 75, 70. 












assimilation of nutriment consists partly in the conversion of binary- 
compounds, carbonic acid and water, into ternary compounds of the 
elements of these substances— into vegetable matter, in fact. In this 
process an excess of oxygen remains, which is then exhaled by means 
of the leaves. The leaves also absorb carbonic acid from the atmo- 


sphere, as has been proved by the researches of Priestley, Scheele, 
Ingenhouss, Spallanzani, Sennebier, Humboldt, and De Saussure. By 
the action of the leaves, the carbonic acid contained in the atmo- 
sphere is decomposed ; the carbon and a part of the oxygen combine 
with the plant, while the greatest part of the oxygen is restored to the 
air. During the night, and in the shade, as well as in an unhealthy or 
fading condition, plants absorb a part of the oxygen of the atmosphere 
and exhale carbonic acid ; but the quantity of carbonic acid thus ex- 
haled is less than that which they ordinarily absorb during the day.* 
Respiration, then, in plants appears merely to serve for the correction 
of the assimilating process. The respiration of plants also removes 
from the atmosphere a part of the carbonic acid formed by animals, 
and yields to it an abundance of oxygen. Animals are nourished by 

matter only, not by inorganic matter; and besides carbon, 
oxygen, and hydrogen, nitrogen also, which in many plants is quite 
wanting and in others exists in very small quantity, enters into the 
composition of animal matter. From the circumstance that a large 
quantity of animal matter is constantly undergoing putrefaction, and is 
thus converted into binary compounds, while animals are quite incapa- 
ble of generating new organic matter from simple elementary bodies or 
binary compounds, it is evident that plants, which have the latter 
power, are absolutely necessary to animals, just as animals on the other 
hand are indispensable for the existence of plants ; for animals exhale 
that which plants inhale, namely, carbonic acid, and inhale that which 
is exhaled by plants, namely, oxygen. Hence, without the existence of 
the vegetable world, the atmosphere would become irrespirable for 
animals; while, by the reciprocal action of plants and animals, the com- 
position of the atmosphere is preserved nearly absolutely unchanged. 

Propagation by shoots and by division in plants. — Plants, having only 
one mode of manifesting life, namely, by vegetation, do not require mani- 
fold organs in addition to their roots, stem, and leaves ; and, with the ex- 
ception of the organs of fructification, present merely a repetition of 
perfectly similar parts, in all of which the simple relation of branches to 
leaves is the same ; and even the sexual organs are evidently allied to 
the leaves, and in some cases are transformed into them. Moreover, a 
consequence of plants thus presenting before fructification merely a re- 
petition of similar parts united by one stem is, that each of these parts 

* Tiedemann's Physiology, Translation, p. 118. Gilby, Edinb. Phil. Journ. 




phenomena comprehends the processes which lead to the formation of 
new germs in an individual, and to the separation and developement of 
these germs; and consequently have for their object the preservation of 
the species, while the individuals perish. 

The above mode of classification has its advantages, but may give rise 
to misconceptions. The force which determines the developement of the 
germ is identical with that which is the source of the constant preser- 
vation and renovation of the individual. The primary forces of the 
animal body would, therefore, appear to be the vegetative, the motor, 
and the sensitive forces; but it is again a question whether even this is 

not an artificial division. _ 

It can be conceived that the essential principle of vegetable lite 
the vegetative force, - may be combined in animals with other forces, 
namely, with the sensitive and motor, or with the nervous power, if the 
contractile power of the muscles is regarded as derived from the nerves, 
and not inherent in themselves. It may be imagined that these forces 
are united in the germ, and that, from the period of developement, 
they manifest themselves in the different systems of organs, which react 
on each other ; so that the vegetative, directed by the nervous force re- 
produces and constantly preserves the organs of nervous life as well as 
other parts, while the nerves again give sensibility to the parts organised 
by the vegetative force. If, however, this theory be reconsidered, it 
will be seen to involve contradictions. 

It is much more probable that these apparently distinct forces are 
merely different modes of action of one and the same < vis essentialis' 
resident in the animal, which modes of action are determined by the 
different composition of the organs. There is indeed an absurdity m the 
very idea that the nutritive force forms the nerves, and that the action 
of these nerves, when formed, results from a force distinct from that 
which formed them. The vital force creates in animals all the essential 
parts, and generates in them that combination of elements, the result of 
which in the nerves is the power of motion and sensation, or the power 
of conveying impressions to a central part, and reflex actions from it. 
The organs endowed with the power of assimilating matters which are 
destined for the use of the indivisible whole, the organs of motion, and 
the organs by means of which a central organ receives impressions from 
all the other organs and transmits its reflex actions, are only the differ- 
ent products of this first and sole principle of animal existence, 
,rimum movens, which produces and reproduces all parts of the body. 
The first set are the organs subservient to the renovation of the body, 
the second the muscles, the third the nerves, - Then there are also parts 
which receive from the creative organic force merely the physical pro- 


perties of hardness, elasticity, toughness, &c. 
cartilages, ligaments, and tendons. 

for example, the bones. 



pJptr.y'of d aurtV eXamPle : ^ " Utriti0n a " d "I™***", acquire the 

and renovation ih„ m i y e Same P rocess of nutrition 

noL speeW & e " ' '•T ! ; rOPe, ' tyWhich ' S th »esult of „ utriti „n, 
vital phenomeTaTh ch . $ T ^ PWCT of "anifesthig their 

ting LrronsUe" al„ 8 r "* mere '{- the "^ of ««'»'»"• Omit- 
force merely ES^X^ ^^ *- the nutritive 

9*« of the animal body may be indicated as folW ° ther P ™ C 'P al 

bloody -CC-y- «*• -■« • the 

dement, in n^lieh ^ t T.^ ."" -T™ «"**»*» »f the 

organic affinity. 

fluids which are in contact with them, 

by exerting an 


nuences, their fib™ b com „ g fl ed n a 2 , UP °" "* Ce " ain '"" 
where a change of their substule^ZS ZZl^t T* 

has named the nrooertv nns„. JT ' and thus sh °"ened. Haller 

influence of mecZ cal T t ^ ""«*» * contracting under the 

the W^S*"!^^ f™"' ***"*' a " d 
while other structures are chara^ is ed b.^! ** " P^. 
kind of excitability. By some writers tiiZmlf'Zf " differen < 

greatly misapplied; thus, they have spoken of a^S *" ""* 
as .fat one toe their irritability, at another th d Zli ST?!* 
undergo a change. In the living body the acti( l „f ?b * , C ° Ul<J 
always determined by their nerves! am/evert ^^1^*"***^" 
composition of the nerves, although but slii,l vnf 7 ?*** " ,e 

as it were, of the nervous force, and, as th tlu'of h " d,8Charge ' 

the muscles. Hence the smd„ „r , thls ' a con traction of 

P-alytic ^^S^ "*■*■- of spasmodic and 
-gnlate ,he action^ tb P t ttf '"a ?. ?= »""«««» of the laws which 

composition • it tah„s „l„ • I accompanies all changes of 

accretion, and an B al Z "* pr ° Cesses »' formation, nutrition, and 

tissues produce th?!?- "? r™* ^'^ ,he bl ° od and the 

muscles are not the , ° accompany tumescence or erection , 

»nly organs which m I P """ '^ ° f m °' ion > but 'W are the 
a" Partf which » T ^ COntractl< »> and zigzag flexure of fibres , and 

f% ^3f dT- t-° C °° ,ra ; t !n ' hiS mannCT ' alth0 "Sb not essen- 

^cuTfibr; tT /° W > ' ? ^ mUSCUlar SUb? ' anCe ' Particularly 
ducts of „, I m ' ermixed wtb their tissue ; such parts are the efferent 

nets of glands, which are distinctly contractile. ' 











■i - 

*V\ c 








has the power of becoming in its turn an independent living body when 
separated from the rest of the plant ; for, besides the generation by 
seed, there is here a generation by shoots. The seed also is an inde- 
pendent part ; the only essential point in which it differs from a shoot 
being, that in the seed the vegetative power is great, while vegetative 
action is very imperfect, or even does not exist. 

In animals, on the contrary, the reciprocal action of circulation, res- 
piration, and the nervous system, is actually necessary to life. The respi- 
ratory movements are dependent on nervous influence : but the nerves 
do not exert this influence unless supplied with blood which has been 
aerated in the lungs ; and the blood again is not sent to the different 
organs, and therefore not to the nerves, without the contractions of the 
heart are performed; while the heart in its turn is dependent on the in- 
fluence of arterial blood and of the nerves. The brain, heart, and lungs 
are therefore, as it were, the main wheels of the animal machine ; which 
wheels react one on the other, and are set in motion, as it were, by the 
change of material which takes place in respiration. The growth of ani- 
mals also is not effected by an external protrusion of new parts, but ge- 
nerally by enlargement of the whole animal-by increase in size of each 
original part internal as well as external. The compound polypiferous 
amma^ afford the only example in the animal kingdom of the^ode of 
growth by new shoots. Most animals, and especially the more perfect 
do not constitute an aggregate of similar parts united by one trunk • on 
he contrary they contain parts of very different vital properties and 
this circumstance renders propagation by division in them ^ImpoJsible 
unless, as in the case of polypes and some annelides,-as the n ^ and 

each of the separated portions still contains the essendal ^rts 

The object of the entire of the foregoing comparison has been merely 
to show how the possession of new properties by animals modifies in them 
even those functions which are common to them and plants 

^f^ion of the functions of animals -The comparison of animals 

2£^T2£ the earlier physiologists their mode of «S 

hav^Zata oT hich plants ? d animais appear to p— - 

and nZ:^:L r JlZ° r Vttah ^ ^^ '" thdr 6nd the P r0ducti - 
are the manifest th /. Se P arate ^ b the ^-existing whole. They 




of the whole. 

are the manifestations of 
or vital force. 

or vital force Th« fe ^^ ^^ ' n the °P erations of the organic 
namely sen^f " S Which es P ecia % distinguish animal beings, 

ex'teL T , m ° tl0n ' th ° Ught ' &C ' appear t0 be the end of ^ 
althJi 6 Cti ° nS h is Which WOuld <*a«cterize the animal 

in com™!^ ! X1Sted ° nly a m ° ment - The ancIents named them «^ 
contiadistinction to the former, organic functions. A third series of 













The nerves are in part motor, in part sensitive. The motor nerves 
are those which, under the influence of changes in their condition so 
slight as to elude the perception of the observer, excite motions in the 
muscles : the sensitive nerves are those which have the faculty of com- 
municating every change which they suffer to the brain, the central 
organ, from which again certain influences are transmitted to all the other 
organ's of the body. Many nerves, arising from the brain and spinal 

^ are, while in connection with these organs, voluntary excitors 

ofmotion in the muscles ; while, under the influence of a change in their 
condition they may become excitors of involuntary muscular contractions, 
whether the connection between them and the brain and spinal cord is still 
maintained, or not. Those parts, on the contrary, which are endowed with 
motion, and are dependent on the sympathetic nerve, are withdrawn from 
the power of the will, and are only, in a certain degree, dependent on the 
brain and spinal marrow, through the medium of the connection of the 
sympathetic nerve with cerebral and spinal nerves. It is in the nerves 
that the mobility of the organic forces, without motion of the ponderable 
masses, is most manifest ; their operation is necessary for the exercise 
of all the functions of the body, since all parts of the system, through the 
medium of changes produced in the nerves, react on the brain and spinal 
marrow, and receive from these organs certain influences necessary for 

their peculiar actions. 

These systems of organs are interwoven in different manners one 
with another. The sensibility of any part is solely owing to the nerves 
which enter into its composition : the organs which serve to produce 
chemical changes in the fluids, if contractile, are so only by virtue of the 
muscular fibres which they contain ; and when there is a secretion of 
fluids in a part endowed with other peculiar vital properties, there is 
always a peculiar tissue for this purpose ; such, for example, is the case 
in the organs of sense, in which fluids are secreted by special tissues. 

Organic attraction.— The reciprocal action of these systems of organs, 
and their nutrition from the blood, cannot take place without the mani- 
festation of affinity in the ponderable and imponderable matters, toge- 
ther with organic attraction. A knowledge of the laws of this attrac- 
tion would be of the greatest importance ; but the facts relating to it 
•which we are acquainted with, although remarkable, are very few in num- 
ber ; such are the attraction of the blood into parts which are capable of 
erection and which are at the time in a state of excitement, and that 
remarkable mode of union of germs by which a part of the double mon- 
sters are to be explained. Such a union of the germs could not have 
taken place without an attraction having been exerted between similar 
_ „ , for in almost all cases the monsters are united by their corre- 
sponding parts, face with face, snout with snout either by the anterior 
or lateral surface, occiput with occiput either by the middle or side, 

parts ; 






neck with neck, breast with breast, or merely belly with belly, or side 
with side, or merely buttock with buttock; the uniting parts of the 
two embryos, in these cases, always becoming single, while the cavities 
of the two are double. A single actual observation of this organic at- 
traction between minute parts would be of the greatest importance. 
But all my endeavours to obtain this desideratum by experiment have 
been fruitless : I placed the nerve of a frog exposed and dissected out 
under the microscope, and watched the end of the nerve while sur- 
rounded by blood-globules ; again I placed some semen of the frog with 
portions of the unimpregnated ovum under the microscope ; but in neither 
case could I perceive anything like organic attraction. 

Animal excitability. — The laws of the excitability of organic beings 
generally, have been investigated in the former section ; the relations 
which the vital stimuli bear to the manifestations of life have been there 
determined. The laws of the excitability of animals will be here more 
particularly set forth, although in the present state of science it is 
scarcely possible to throw any light upon this difficult problem, a know- 
ledge of which however is so desirable, since it is here that practical 

medicine has much to expect from physiology. 

Whether the vital principle or organic force is the result of the combi- 
nation of ponderable and imponderable matters, or itself determines and 
maintains the peculiar composition of organic matter, it is an observed 
fact, that under certain circumstances this force becomes strengthened 
in particular organs, of which in this case the action becomes greater 
and more continued, as is observed in the genital organs during preg- 
nancy and the sexual ardour. Thus also the organic force is observed 
to become less in the antlers of the stag just before they fall off, and 
to be again increased when they are reproduced in an organised state. 
An accumulation of organic force in a part is accompanied by an in- 
creased afflux of blood, and a more abundant conversion of blood into 
organised matter. Tiedemann remarks, that an organ in an excited 
state undergoes more rapid changes in its material composition, and 
therefore attracts more quickly and in larger quantity the blood, which 
alone is able to render an organ capable of increased vital action/* 
When, on the other hand, any organised part has suffered a lesion from 
change in its material composition, in that case also if the destruction of 
0r ganised texture has not been too great, increased action ensues for the 
Purpose of restoring the healthy state. Organised beings have the power 
°f preserving in all parts the composition necessary for the life of the 
w hole. When the composition is disturbed, the curative effect of this 
power is manifested. This is a necessary consequence of the law, that 
in organic bodies there is a constant striving to counteract chemical 
Unities. Hence the increased flow of blood to an injured part arises 


* Tiedemann's Physiologie, i. p. 32G. 

E 2 







from the organic action in it being increased. The reciprocal action 
of the increased organic process, and of the commencing tendency to 
decomposition in the part, on each other, is seen in inflammation. In- 
flammation is not essentially a state of increased action, but is com- 
pounded of the phenomena of the local injury, a tendency to decom- 
position in the part and increased vital action striving to balance the 
destructive tendency. When the degree of change of composition in 
the animal tissues is greater, reaction does not ensue, and inflammation 
is not produced ; such is the case in death by narcotic poisons, 
inflammation does occur, the change produced by the injury may soon 
become so great that the organic reaction is not able to counterbalance 

it, and local death ensues. 

These and many other cases, even the fatigue and ex- 
haustion which follow great exertions, show that the organic force is 
consumed as it were by the exercise of the functions. This circum- 
stance is evident even after death ; for if we take two similar portions of 
muscle of an animal just killed, and excite in the one slight contractions 
with a knife, while the other is left unirritated, the first portion will 
lose its irritability sooner than the other, and the difference will be 
proportionate to the number of contractions which have been excited 
in it.* In the same way every impression of light deadens the power of 
vision in some degree, and an equal stimulus immediately afterwards 
does not produce an equal reaction ; the eye requires rest. 

This might be explained by supposing that a part of the organic force 
is exhausted in balancing the material changes produced by the sti- 
mulus. But exhaustion also ensues when the action of an organ is in- 
creased without any external stimulus, if the organic force is not increased 
at the same time. It appears, therefore, that the very action of organs 

produces a change in their composition 

It may be that the constant 

change which is produced in the organic substance by the action of the 
arterial blood, and which is as necessary to life as the decomposition of 
the burning matter is to the phenomenon of combustion, is accelerated 
or increased by the action of the organ, while the renovation from 
new nutritive matter does not take place with proportionate rapidity, and 
can only be effected gradually during rest. Generally, however, the more 
exertion a man uses, the more active seems to be the decomposition of 
the matters in his body, and the more need has he for nutriment. Both 
men and brutes that have died after very violent exertion, as in the 


instance of a stag hunted to death, undergo putrefaction much sooner 
than animals bled to death. Autenrieth,t who makes this remark, also 
instances, that a muscle taken from an animal before irritability had 
ceased, putrefies much sooner if stimulated to frequent contractions, 

* Autenrieth's Physiol, i. 63. 

t Physiol, i. 115. See also Humboldt uber die gereizte Muskel und Nerven-fiiser. 


than if left at rest. L 

rest is «n ™ , " "° " l uie IM3rvous system especially, 

t is so necessary, that even a life the most tranquil requires sleep 

Itrzir. while the causes which excite the ™ W 

svstetT- ^ G eXtenial Stimuli ' are in operation; the nervous 

C nTz e r n ;: d - nsensible to these impressi ° ns ^ — * ™ 

range induced in it by its state of activity. 

ordinandi r?™*"* the tis — "y the general vital stimuli 

ilrta S "'* ° f a W*»— — cise of their func- 

Cc^rv to rel^f " ' S T"* "* ™ d ™e«> -bseonent rest 
consnmed "' P ° We '' *" new acti °» - b» been thns 

generated in ^"^ ' m th f . health y sta '«. j-t as mnch power is 

generated m a certain space of time as has been exhausted by the exer 

c se of the functions ; but there are cases in which the nutriL „f Z 

organ becomes gradually increased while the state of action is either 

eaual anrl vomilo^ ii. ,• .., ° clu *er 

equal and regular, or alternating with 

rest. This is the case, for instance, 

l y Zt bec r e d the affi r ° f the tiss - ^*sz: 

omp Z e in rt y S ' ated ' l ° " e grea ' er Whe " the "-elopement is les 
~ h'v '■ Catmi !pariiuS ' ,hc P° Wer of « ««■» - ""-ays in- 

creased by exercise, not carried too far, and alternating with rest • 
while mere rest often weakens an organ. This alternation of » 

and roof • *!, , 6 alternation or exercise 

a rest is the means by which a gradual increase of strength is to 
ac quired Llfe generally is attended with decomposition of organic 

W ith L m r 6 ?* PCrh T' ^ aCti ° n ° f an °*Z™ is ""ended 
Jith decompos, .on of a part of its material, while another part be- 

comes more intimately combined, so that, although 
loses matter by its state of action, still the 

more capable of attracting new material and of strengtLnfogSelf! 
tfut when the action is repeated too frequently and violently, the 
renovation of material is even less, and exhaustion ensues. This is 
the case when the vital force is consumed, or rendered inert, by in- 
creased action, more quickly than renovation can be effected. The 
exhaustion is so much the greater, the more numerous and the more im- 
portant the parts of which the action is thus frequent and violent, as, 
or example, in coitus, in which nearly the whole nervous system is 
lr own into a state of activity, attended with consumption of vital force • 

an organ really 
same action renders it 

organ is attended with a loss of 

— — ^^^^ ^^ ^^ ^^ "^^ r^^ ^mrwf ^^ ^* ^k& M* JK ^_- j *m ^^_J ^^f%W TV MM I ■ ■ ^^ft ^^fc 

fornething which it imparts to another part, as seems to be the case 
| n the action of the nerves ; and, lastly, the more the action of the part 
* s attended with a real loss to the whole system, as in the case of 
increased secretions, for example, of the milk. The momentary state 
of inertness of the vital force after action, and its gradual restoration 

in parts of frogs separated from the body; the irrita- 

l _* A\- _ _ _ I ^ ^a a L _-^ L I _*_ — L-^ tea « A- 1a _t**_ tek ^ JL _ _ I J I ■ * mn ■* 

seen even 

oiiity being restored probably by the action of the blood still 








1 * 






tained in the part, as well as by that of the air on the tissues. 

the repeated application of galvanism to the leg of a frog separated from 

the animal exhausts its irritability, which is again restored after a certain 

interval of rest. # ' ■; _ 

If an organ is very rarely called into action, its power is not restored 

by rest in the same degree as when it is subjected to more frequent 

^^ The eye, for example, requires rest after being in action ; but 

by alternating exercise and rest it is strengthened. If the eye is kept 
long in complete rest, it will have acquired great sensibility; but the 
vital force will have become weaker in proportion to the time that it has 
been left without exercise ; and a strong impression of light will be 
sufficient even to blind an eye which has thus been kept long in darkness. 





of the muscles of the ear, for instance, is lost for want of being exer- 

Reaction —Hitherto change in the organic activity of animals has been 
considered merely in a general manner. The operation of external in- 
fluences in producing change in this property of animals shall now be 
investigated. The external « vital stimuli" are not the only agents which 
give rise to vital actions ; everything which disturbs the elementary 
composition of organs, and the balance in the distribution of impondera- 
ble matters in the organic tissues, may also modify the action of the 
organism and of the separate organs. Such a modification when consi- 
derable is called reaction ; the influence which produces this reaction 
in the organism is called irritation ; and the cause exciting this irri- 
w „,„, the stimulus or irritant. The reaction is always a vital pheno- 
menon, a manifestation of an organic property of the animal system. 
The property of reaction, of being excited to the manifestation of some 
inherent power on the application of an external influence, is not con- 
fined to organic beings, and still less to animals. Light or warmth 
are developed from many inorganic bodies, under certain circumstances, 
for example, by a blow. In these cases it is probable that the light and 
caloric existed in the bodies in a combined state, and are set free by 
the action of the external influence. A still better instance is afforded 
by elastic bodies, the minute particles of which have such an attraction 
for each other, that an attempt to displace a portion of them acts upon 
the whole • and by the power of attraction between them a restitutio in 
integrum ensues, accompanied with the phenomena of elasticity or sono- 
rous vibrations. But no inorganic bodies are so uniform in their mode ot 
reaction as the organised bodies, which, under disturbing influences, 
however various, always manifest the same phenomenon,-^ namely, 
with the capability for which each organ is endued by hie. ■ ~ -— 
formity in the mode of reaction of organised bodies arises probably from 

The uni- 

* Autenrieth, Physiol, i. 104. 



in it. 

that fundamental property resident in them, of counterbalancing disturb- 
ances in their composition, by a force which, in the healthy state of the 
body, is much stronger than the disturbing cause. The force which 
restores the balance in the composition of the tissues after such a dis- 
turbance, is identical with that which preserves all the properties of a 
part during the constant process of nutrition and renovation of material. 
The phenomenon which ensues on the restoration of the balance, is con- 
stituted partly by the change produced by the external cause, and partly 
by the effort exerted to restore the balance. Dutrochet* maintains that 
all stimulants produce the same change in the organism,— that they 
modify the state of oxidation of the organic matter on which they act; 
the stimulant, he says, acts simultaneously on the oxygen and the organic 
matter, causing them to unite. Ingenious as this theory is, it is at^pre- 
sent a mere hypothesis ; as is also the conclusion that Dutrochet comes 

to, namely, that excitability is really a state of susceptibility of oxida- 


^Irritation of an organ must always be attended with some material change 
^ Such a change indeed must be presupposed even in the effect of 
the stimulus of light upon the eye. Light appears to enter into the com- 
position of many bodies, and produces chemical changes, which are 
evident in several chemical preparations, and even in plants, in which 
light causes the developement of oxygen. The immediate effect which 
a stimulus produces, varies with the nature of the stimulus and of the 
body irritated ; thus, it may be compression or a chemical change. 
But the secondary effect — the effort to counteract the former— is quite 
independent of the nature of the stimulus, is not mechanical or che- 
mical, but is a manifestation of the vital property of the organ, such 
as sensation, manifested by pain, or inflammation, or spasm. Caloric, 
electricity, and light are imparted to organised beings according to the 
general laws of physics; but in the "restitutio in integrum" there always 
arises, at the same time, a vital action, which differs in its kind accord- 
mg to the part that has undergone the change ; and the phenomena 
observed, until the part is restored to its natural state, are compounded 
°f the operation of the stimulus and the reaction which it has excited. 
Chemical substances also produce a change in organic bodies, and have 
a tendency to form binary compounds with their elements. If this 
occurs, — if the organic affinity is not able to counteract the chemical 
agency, — a chemical product is formed, at the same time that the life of 
the part is destroyed, as is observed in the case of burns, and of the 
a Pplication of mineral acids or a caustic alkali. But the organised struc- 
tu re, thus acted upon by a chemical agent, while it retains its life, and 
°n the boundaries of the part after its death, manifests the organic pro- 
perties peculiar to it, such as sensation, motion, or inflammation. 

* Froriep's Notizen. 724. Stances de l'Acad. d. Sc. Jan. 30, 1832. 


I I 




The reaction of animal bodies on the application of external stimuli 
is peculiar, not merely in being manifested by vital properties, but these 
vital properties are frequently different, according to the nature of the 
organ and of its composition. Thus, for example, mechanical, chemical, 
or electrical stimuli applied to a muscle, all produce in it the same mode 
of reaction, namely, motion. So, also, all the different stimuli applied to 
a sentient nerve, excite sensation merely; and the kind of sensation is very 
different in different nerves, when the exciting cause is the same, and the 
sensation produced in the same nerve is always the same, although the 
exciting causes be different. Thus,, for example, mechanical and electric 
stimuli excite, in the optic nerve, the perception of light, which is the pe- 
culiar property of this nerve, and seem to excite no pain; while pain, and 
not the perception of light, is the constant result of irritation of a sentient 
nerve. In the same way, mechanical and electric stimuli produce in the 
auditory nerve the perception of sound, and electricity excites in the 
olfactory nerve the sensation of smell. The anterior roots of the spinal 
nerves when irritated mechanically or by galvanism, give rise to no sen- 
sations, but to muscular contractions ; while the posterior roots of the 
same nerves, under similar circumstances, excite sensations only, no 
contraction of muscles. By knowing the mode of reaction peculiar to 
all parts of the body, physiology acquires an empirical knowledge as 
certain as any possessed by the other natural sciences. 

In perfectly different diseased states of the same organ the symptoms 
are often very similar ; for in a state of excited action, as well as in a 
state of irritation with diminished power, the organ will manifest the vital 
properties peculiar to it. There are certain groups of cerebral symptoms, 
and of symptoms of cardiac disease, which occur in very different morbid 
conditions of each of these organs respectively. We may here remark 

upon the folly of the homceopathists, who imagine that they can cure dis- 
eases by means of substances which shall produce states of the system re- 
sembling the diseases; while they either do nothing whatever, or nature 
applies the remedies otherwise than the homoeopathist imagines. The 
fact of two substances producing similar symptoms in one organ does not 

prove that these substances produce exactly the same effects, but merely 
that they act on the same organ, while the essential actions of the two 
may be very different. Syphilis, and the mercurial disease, may be 
essentially very different, and yet they so far resemble each other that 
certain organs are affected by both. Mineral acids and alkalies, also, 
are equally destructive to the organised tissues, and nevertheless no one 
will assert that they are "sirnilia" In the same way, mercury, by inducing 
a slight change in the organic matter of the body, may render it unfit 
for propagating the destructive process of syphilis ; and then the natural 
vital process, and not the mercury, effects the further cure. 

The action of an organ being excited by stimulants, and every increase 



SZ^JEEZZZ 1 °T' C force being " d 

general **rf *Wt, the y hav / at t „; «. " '" * C " Se ° f the 

temporary cessation of the action rht^ 7 reSt ° ra ' ive aCti ° n ' a 

follow, although theil . ;nflu I » y have themselves excited win 
racter of many vital phenomena A , . , ' enCe the P eriodic cha- 

jWeh stin^es ^-SS^ i^^^**^ • -tter 
of eontraction the part is rendered t k * ; ontracte - By this act 
contracting with eq P uaI !t J^^ "J '% f »» -men,, of again 
«ored, and the stimulus, wh f ch s "£ £™** * *"*'*>' ~ 
and so the contractions are repeatedTo" . " **** eSectiv * ' 

mittent action is seen in the ZT, , 1'°* '° time - This »ter- 

ence of an eouable lg M, ££*££ ° f f ! ™ aad " the i„ flu . 
intestines, stomach, he^rt, ulert,^ bid'" % * ^ 
winch expel the contents of the urethra in co.tu Th , ," """^ 
traction is, in these cases, frequently externa, » „?! ' *° ^ 

the cavity „ f the organs> , J ag J™ ' * c sub ;'»oe contained in 

also to be frequently intPm«i f • * appears, however, 

as in the case of h e W t ' TT? * * ***** from the nerves > 
to be attributable to nt ? t . he / h ^ thmic ^'actions of which appea 

vacuum. e actlon continues in a 

A stimulus, too often repeated, deadens the excitabiH. v ^ a 

be explained a part of the phenomena observed in eL72 

aitho„ gll many things which this insens . b b ;'; of * '• 

produce not merely the phenomena of excitement at firs,, but a du able 

rue ural change, whence alone the subsequent inefficiency o the 1 

stimuli can be explained. y ese 

Classification of rnedieinal agents.- As the modifications produced in 
the composition of the organised tissues by the numerous agents and sub 

rm "d ' ^ I""" 6 " 06 ° f WhiCh "» °^ nism is **~* a're „ various 

*se ^iZ7lZ ymS " C0 1" g '° * e " atUre and oo mP ositi„r o f 

na u^of ^ch modTfi "r CeS '~ and " "* ™» U " abIe t0 "otermine the 
nature o each modification, a „ impossible to bring the substances u«ed 

m med.cme under a general good arrangement. Viewing them generalTv 
however there can be but three principal modes of action, Id three' 

classes of agents. 

1. Stimnlants.-The true and most important stimuli are the vital 
stimuli themselves, the constant operation of which on the tissues is 
alone the cause of the manifestation of life, and of the increase of the 




vital force.* The vital stimuli are, a certain degree of external heat, 
atmospheric air, water, and nutriment. These agents do not merely 
produce a change in the composition of the organic structures and stimu- 
late by disturbing the balance in the system, but renovate the tissues by 
entering, in a manner indispensable to life, into their composition. These 
influences, which are constantly in action, and which, while they stimu- 
late, leave no exhaustion after them, are the only efficient means for 
restoring the powers of the body after an illness. There are many other 
stimuli which excite reaction, but which are not essentially renovating, 
and indeed for the most part have no restorative action on the organs; 
and which, except in producing symptoms or phenomena of reaction, have 
no vivifying influence; but, on the contrary, are injurious in proportion to 
the change effected by them in the organic composition 
jury has been done to medicine, and many lives have been lost, through 
the error of confounding all agents which excite reaction in the system 
with those which are absolutely essential to life, and which renovate while 
they stimulate the organs; the false notion having been thereby induced, 
that because certain stimuli feed as it were the flame of life, stimulating 
agents generally are necessary to life. There are however some agents, in 

addition to the general vital stimuli, which under certain conditions 

An endless in- 


exert a local, vivifying, and strengthening influence ; they produce this 
effect by restoring the composition of the organ by their ponderable 
or imponderable influence, or by so changing its composition that the 
renovation by the general vital stimuli is facilitated. All this, how- 
ever, depends on the state of the diseased organ ; and the cases in 
which the so-called stimulant and tonic remedies have really their sup- 
posed effect, are very rare, 
have been stimulated to death by a host of remedies which, under the 
circumstances of the case, or in all cases, stimulate, it is true, but only 
produce a tumult in the system, and do not strengthen it. Those sub- 
stances which under certain conditions have a vivifying influence, also 
act principally, according to their composition, on different organs, and 
form natural groups according as their principal action is on the nervous 
system or on the organs destined to effect changes in the blood. Several 
of these agents are imponderable matters, such as electricity, which 
has been used with success in paralytic affections. Caloric, that agent 
which is necessary in the developement of the embryo, has also an emi- 
nently vivifying influence, when other means are fruitless; for in- 
stance, in affections of the nerves and spinal cord, — paralyses, neural- 
gia dorsalis, and commencing tabes dorsalis ; the application of heat 
being made, for example, in the form of moxa, and frequently repeated, 
even by a new moxa on the old granulating surface : the application of 


* See section 2. p. 29. 



neat?tt t ~ mCTe tnfl,ng - A mUCh m ° re durable ****** ^ 
*>g and e nl h r t T "^^ ^ * pr ° duCed by hold ^ a ^urn- 
P^n bv ^ht h Vf Ct6d ^ f ° r a Ion * time ' *° as *oUduce 

"he formltt f 6anS ^ ^^ ^ ° f heat is obtained > *** 
often of* an ^char and the subsequent suppuration, which is 

* not evlT" The m ° de " Whidl the Cal ° ric acts in *~ -ses, 
*hen S ; r^ ^ beneficial in diseases of the spinal cord, only 

of the bod y ! t0 ^ WhHe Pain may bG 6Xcited in ™y P art 

vivifvW an ! Cal i 1 nfluence in frictions act s «nder certain circumstances as a 

Position o?r UUS; k haS thl ' S effeCt ' Pr ° bably ' hy indudn ^' in the co ^- 
the affinit f SSUes ' sh g ht chemical changes, as a consequence of which 

p-im'l *• • the tissues for the g en eral vital stimuli already in the' or- 
ganism, is increased. 

as cdor^ ^ haml aH ag6ntS ° f this kind ' as Wel1 m edicinal substances 
tusion 1°' ectncit * and mechanical influences, such as pressure, con- 

of a vivifl 111 * ff WhC v th6ir aCti ° n iS eXC6SSive ' haVe the ver ? °PP° site 

matte r! ? .1 ' bj F ° dUCing SUCh a Vi ° lent chan S e in the organic 
hence '^ I' 6 Combinati °ns necessary to life cannot be maintained: 

condkionT rf 6nCeS are Spedal StimUli ' Vivif > in ^ ° nly under c ertain 
omw eJ 6Xert a Vivifyin ^ m^ence when their action on the 

pans Th ttCr S thC P roduction of *e natural composition of the 

orhpr r 7 maj ' therefore > be terme d homogeneous stimuli; while all 
and tb T ' WhlCh ° nlj diStUrb the natural composition of the body 

and thus the state of the vital powers, may be termed heterogeneous ^£1 
these have no vivifying influence, but ratber an injurious influencTt 
hfe. It must however be remembered that every homogeneous stimulus 

when used under improper circumstances, becomes a heterogeneous 2 
mulus. The st.mulants thus would seem to be divisible into 1 the 
general vital stimuli ; 2. the special stimuli ; and these again are 'divi- 
sible into a, the homogeneous, and b, the heterogeneous. I have alreadv 
—ed that Dutrochet supposes the true stimuli to act by IvtnW 
and accelerating the combination of oxygen with the organic matter It 
js probable that the action, at least of several stimuli, depends on their 
iavmg the property of strengthening the affinity between the organic sub- 



) and thus of increasing and accelerating 
^ organic matter by this principle (oxygen) Ii 



In cases of rapid sinking of the vital force, all our stimulant remedies 
are of no avail ; and the greater part of such remedies merely excite 
the system, and do not add to the strength. 

2. Alteratives. — A great number of substances 

are important as 

medicaments, from producing a chemical change in the organic matter of 









which the result is, not an immediate renovation of material and increase 
of vital force, but the removal of that state of combination of the ele- 
ments which prevented healthy action, or excited diseased action ; or 
the chemical change produced is such as to render the organ no longer 
sensible to a morbid stimulus ; or it is such that certain apprehended 
destructive changes in its composition are no longer possible, as in the 
antiphlogistic plan of treatment ; or, lastly, these substances produce a 
change in the nutritive fluids. Such substances are alteratives. By 
these remedies an organ morbidly changed in composition cannot be 
rendered sound by, as it were, a chemical process, but such a slight 
chemical change can be produced as shall render it possible for nature to 
restore the healthy constitution of the part by the process of nutrition. 
These remedies again may be divided into two principal kinds, according 
as they act chiefly on the nervous system or on the other organs depend- 
ent on that system. Among those of the first kind the most important 
are the so-called narcotics ; those of the latter kind comprehend the 
numerous medicines which exercise their action on diseases in other 

These remedies also, by removing the obstacles to cure, be- 
come indirectly vivifying or renovating stimuli, and they may them- 
selves, by disturbing the balance in a part, produce symptoms of irri- 
tation! If used in excess, they either give rise to the injurious effects of 
the heterogeneous stimulants, or, by inducing a sudden change of compo- 
sition, annihilate the vital force, as is the case with the narcotics. Since, 
however, such alterative medicines affect the composition of an organ 
each in its own way, one alterative may, after a time, lose its influence, 
as it were, from saturation, while the organ may still be susceptible of 
the influence of another. A great number of the instances of habitua- 
tion are referrible to this cause. The administration of medicines affords, 
in innumerable cases, the confirmation of this statement. By the con- 
tinued use of an alterative medicine, the composition of the organ shall 
have suffered such a chemical change, that the same affinity for this 
substance no longer exists in the organism, while an affinity for another 
substance may still remain. Imponderable matters also are in this way 
alterative ; thus the eye, after being long fixed on a green surface, be- 
comes gradually more and more insensible to this colour, which becomes 
dull and grey. At the same time, however, the sensibility for the red 
rays is increased, and a long exposure of the retina to the red rays 
makes it susceptible of the green. In the same way, by fixing the eye 
long on yellow, the sensibility for that colour is lost, while the percep- 
tion of violet becomes more intense, and vice versa ; the same relation 

exists between blue and orange. 

3 Agents which destroy the organic composition. (Zerzetzende mittel.) 
—These are influences which, without first producing a stimulant or 
simply alterant effect, directly destroy the essential composition of the 





organised tissues. Some of the agents which are stimulant when 
they operate gently, produce by a more violent action too important a 
disturbance of the powers of the part ; such are heat, electricity, &c. 
Others are alteratives, which by an extreme degree of their action 
produce great changes in the composition of the tissues, forming with 
organic matters combinations which the organic force is not able to coun- 
. alance ' li is in this way that the narcotic alterants have a destruc- 
tiveaction ; and those alterants which modify the formation of the fluids 
* e body and the organic changes effected in them by different organs, 
or example, the antimonial and mercurial preparations, and the mineral 
acids and alkalies,— have, when in a concentrated state, an equally de- 
uc ive influence on the organic composition. Stimulants can produce 
disorganisation in two ways. They may, in the first place, be stimulants 
y when their action does not surpass a certain degree of intensity ; and, 
en their action is more violent, they may, instead of renovating the 
material, or even favouring this renovation by exciting new affinities, pro- 
uce immediately an essential change of composition. In this case no 
irritation or reaction precedes the local or general death; the disorganisa- 
tion is immediate, as in death from electricity, lightning, &c. Or, secondly, 
a stimulus, which under certain conditions has a renovating action, may 
have a destructive effect by exciting the action of an organ during too 
ng a period ; more force being exhausted than can be restored again in 
an equal space of time. This action is called over-excitement. An 
organ thus over-excited, as, for example, the eye by light, is rendered 
permanently weaker. The agents here referred to are used in medicine 

only when it is wished really to produce destruction of a part. 

John Brown, who, by 

the discovery of some of the laws of excitability, was enabled to give 



in his 


medicine, but in a crude, and, for application to practice, dangerous 
form, was as little acquainted as his followers with the mode of action 
of alterative medicines. According to Brown's theory, no change can 
take place in the state of the excitable powers without previous excite- 
ment; and it is only by over-excitement thaf the excitability, with life, 
can be exhausted. The Brunonians were obliged to maintain, that, 
whenever exhaustion was produced by any influence, absolute over- 
excitement had preceded this exhaustion. As proof of this assertion, 
they adduced the circumstances that many substances administered in 
small quantity stimulate, in larger quantity produce quite a different 
state, and in still larger quantity cause exhaustion : opium was their 
example. In the last case, when exhaustion is produced, the period of 
excitement is extraordinarily short and imperceptible. They explained 
the action of all agents which rapidly produce exhaustion in the same 
manner. But there are many substances which, even in small quantities, 


1 19 





^^ —*** -' 




produce these disorganising effects in a slighter degree ; such are the 
irrespirable gases, the poison of the viper, &c. The contra-stimulists, 
Rasori, Borda, Brera, and Tommasini, perceiving this defect in the 
Brunonian theory, gave the name of contra- stimulants to those substances 
which, in place of stimulating, have the very opposite effect, — that is 
to say, diminish the excitability of parts ; so that they have divided 
their medicines into the stimulants and contra-stimulants : but, although 
they have not overlooked this great error of Brown, they have failed 
to recognise that alterative action of many medicines which has been 
pointed out in the preceding pages. 

The distinctions made by Brown originate in a very partial appli- 
cation of some well-grounded laws of excitability, and in the error of con- 
founding the renovating vital stimuli with substances which modify the 
action of organs and their healthy composition, and which in that respect 
stimulate, but do not renovate at the same time. A narcotic— that is, 
an alterant of the nervous system,— may from the commencement to the 
end of its action produce symptoms ; by changing the organic composi- 
tion, it acts upon that fundamental property of the organism by which 
external influences determine them to action in accordance with inter- 
nal laws, or, in other words, stimulate them. But this is not a stimu- 
lant in a therapeutic sense ; by which is understood an agent which 
vivifies the organs, and renovates their composition. 

John Brown divided diseases into the sthenic and the asthenic. In 
the former, he supposes the vital force to be increased ; in the latter, 
diminished. But a disease with increased vital power involves a con- 
tradiction ; and diseases present merely an endless variety of defects in 
the composition of organs, in which the general forces at one time fail 
from the very beginning ; at another time, are present at first, but after- 
wards diminish: the best mode of arranging diseases, therefore, is 


founded on the different systems of organs affected, and the types of 
disease established by their natural history. Physicians have always 
been inclined to regard inflammation as a disease with increased vital 
er : but it is in reality a disease in which certain properties of the 
body are undoubtedly increased, — for example, the heat ;— in which the 
quantity of the blood in the capillaries is greater, but in which other 
conditions of the part are altered; while the function of the organ is in- 
terrupted, and the sensations indicate a violent lesion. The exciting 
cause of inflammation produces a chemical change in the composition of 
an organ ; it is in this way produced in the practice of medicine by che- 
mical agents. A chemical affinity, an attraction, may arise between the 
blood and the tissues thus chemically changed. This affinity may be 
greater than in the healthy state. But whether the increased affinity 
between the tissue and the blood in inflammation be merely a greater 
degree of the natural organic attraction, such as is observed in certain 












healthy phenomena, as in all the phenomena of tumescence, „ 
whether it is essentially different from the organic attraction, and is a 
newly arisen chemical affinity between the disorganised matter and the 

ffl d '~~ Cann0t With certaint y be determined. But even if the increased 

affinity between the blood and the organic substance be really a greater 

gree of that reciprocal action which is constantly going on between 

e blood and the tissues, still inflammation is not a disease of increased 

power ; for the phenomena of inflammation arise as much from the 

existing tendency to decomposition excited by the chemical change, as 

rom tlle taction of the tissues to oppose this destructive tendency. 

e mt ^ate reciprocity of action which exists between all parts of 
organism, especially through the medium of the nervous system, 
produces in animal bodies a kind of balance ' - - 

« X • / 

e it results, that an exciting cause of disease acting on one part, 
j[ changing tne state of tne ponderable and imponderable matters, 

exerts its influence through a chain of such changes on distant 
Parts, which are most susceptible of this form of disease. It is _„. 
re y that the withdrawal of matters at one point prevents the accu- 
mulation of similar or different matters at another spot, on which is 
ounded the use of evacuating means at parts of the body distant from 
isease ; but the increase of vital action in one organ excites many 
ers: hence the connection of the increased vital action in the genital 
organs with the reproduction of the antlers in the stag, and with changes 
m many organs in man, which changes, both in the stag and in man, 
are prevented by castration. The application of renovating stimuli, 
also, to one part, has a vivifying influence on the whole system, reacting 
from the skin, for example, on the central organs of the nervous system 

through the medium of the nerves ; whence arises the successful use of 
frictions, and other stimulants to the skin, for the restoration of sus- 
pended animation. 



4. Of the phenomena, or active properties common to inorganic 

and organic bodies. 


Organic bodies participate in the general properties of ponderable 
matter. The laws of mechanics, statics, and hydraulics, are also appli- 
ca e to them. Several of these properties which organic matters may 
possess in common with inorganic substances, such as cohesion, elasti- 
city, &c. exist, however, only while the essential composition of the part 
is maintained by the continued operation of the organic force ; thus the 
elastic coat of arteries loses its elasticity soon after death. The appli- 
cation of the laws of mechanics, statics, and hydraulics to the actions 
ot organic bodies is also limited, from the circumstance that the causes 
of motion most engaged in them are essentially vital in their nature. 




The imponderables, also, namely, electricity, caloric, and light, are de- 
veloped by organic bodies. It is these matters that we must here par- 
ticularly consider, 


1. Developement of Electricity. 

The electricity excited by friction is well 

known to be developed more especially from many substances of organic 
origin : galvanism, or the electricity of contact, is not produced merely 
by the contact of heterogeneous metals ; many other substances, par- 
ticularly carbon and graphite, may, as has been shown by Humboldt 
and PfafF, supply the place of metals ; and even many animal substances 
connected by conducting bodies will produce in a less degree the same 
phenomena as metals of different kinds. It would, therefore, be quite 
erroneous to suppose that the causes of galvanism are to be sought only 
in the properties of different metals. Seebeck has discovered that even 
bars of the same metal heated to different degrees of temperature, and 
placed one upon the other, will become electric ; and that one simple 
metallic bar made of a different temperature at the two ends has the 
same property: so that different quality of the parts coming in con- 
tact (by throwing the electricity which is present in all bodies into the 
state of positive and negative electricity, or by disturbing the balance 
of the electric matter,) together with connection by means of a con- 
ducting substance, seem to be the most general conditions required 
for the production of galvanism. Galvanic phenomena are also pro- 
duced in the parts of animals under these circumstances. The Baron 
von Humboldt discovered that feeble contractions are produced in the 
leg of a frog by touching the nerve and muscle at the same moment 
with a fresh portion of muscle. This is certainly one of the more rare 
results of galvanic experiments ; but I have repeated the experiment 
several times, and can confirm the accuracy of the result. Buntzen 
indeed formed a weak galvanic pile with alternate layers of muscle 
and nerve ; and Prevost and Dumas state that a circle formed simply 
of one metal, fresh muscle, and a saline solution or blood, affects the 


If to the conductors of the galvanometer, plates of 
platinum are fixed, and a piece of muscle of several ounces' weight 
placed upon one of these plates, the conductors being then immersed in 
blood or a saline solution, a deviation of the magnetic needle of the 
instrument takes place. Or if to one of the conductors, a piece of pla* 
tinum moistened with muriate of ammonia or nitric acid is attached, to 
the other a portion of nerve, muscle, or brain, and the two conductors 
made to communicate, the same deviation is produced.* Kaemtzf has 
moreover shown, that dry but efficient galvanic piles can be constructed 
from organic substances without any concurrence of metals. Concent 


Magendie's Journ. t. iii. 

t Schweigger's Journ. 56. 1, 


•Wi disks rffh! ° rgi "" c , substances ™« spread upon thin paper, and 
<"» subs^ees he- PaPer P *" •'"" *■*«««* the two layers of differ- 

np»Kl_ , . peQ D ^ these P ll es was tested bv an eWtrnm^r /r„k 



Linseed oil 

Linseed oil 



White of egg 
White of egg 
Bullock's blood 
Bullock's blood 

It was by this means ascertained that 

w positive with i 

eference to Mutton fat. 

Cane sugar. 
Common salt. 
Sugar of milk. 

White wax. 


Mucus of tragacanth. 

Seeds of lycopodium, (barlappsamen.) 

Bullock's blood. 

Extract of belladonna. 

although ! 8 Vn ' thG el6Ctric fishes a PP ear less extraordinary, 

life L , P ° Wer ° f Pr ° dUCing deCtric dischar S eS exists <>n\y during 

elect^ fi ^l ^ Undisturbed state of the nervous influence. The 

which th. T b6St kn ° Wn are the eleCtHc ™y> or torpedo, of 

nich the species ocellata and marmorata occur in the seas of the south 

seveZ° Pe ' ! o leCtriC eel ' ^ mnotus electricus, which is found in 

e era nver S of Sou th America ; and the silurus electricus, or malapte- 

rurus electricus, met with m the Nile and in Senegal. The rhinobatus 

electricus, trichiurus electricus, and tetrodon electricus 

known. Walsh 

are less 

a . o' — j ~~«*«*,, anu x^uiiiDoiat, have cor 

tributed most to our knowledge of these fishes. 

The electric organs of the torpedo lie on each side of the' head an 
gills, and consist of a number of five or «iv. fi M^ ™u_ ^^ 

five or six-sided prisms placed per- 

pendicularly side by side, and occupying the whole thickness of the 

an Each prism consists of a tube with thin membranous parietes, 

surrounded with nerves and vessels, and containing a great number 

<one hundred and fifty) of extremely thin lamella,, lying transversely, 

Parallel one above another, with a gelatinous fluid in the intervals 

inree large branches^ the vagus nerve are distributed to these organs 

on each side, branches being previously given to the branchiae A branch 

ot the fifth nerve also is distributed to" the anterior part of each organ * 

ihe electric organs in the gymnotus and silurus are described by Rudolphi 

to extend from the head to the tail, two on each side ; one of these is 

situated deeply, and one superficially, the two being separated by a 

septum, and in the gymnotus, at the sides, by muscles also. In the 



* Hunter, Philos. Trans. 1773, p. ii. tab. 20. 


■ ■ , 




gymnotus electricus the organs are formed of horizontal membranes 
extending longitudinally, one-third of a line distant from each other, with 
septa passing perpendicularly between them and running from within 
outwards, the spaces between these septa containing a fluid. The smaller 
deeply seated organ is still more finely divided. The nerves are two 
hundred and twenty-four intercostal nerves, which descend at the inner 
side of the organ and distribute branches in each layer; the minute 
terminations of the intercostal nerves themselves passing under the 
small organ to the skin. A nerve, composed of branches of the fifth 
and vagus nerves, passes superficially, and is distributed to the muscles 
of the back without giving branches to the electric organs.* 

In the silurus, Rudolphi ascertained that there are also two elec- 
tric organs on each side ; the following account of them is derived 
from my own observation, as well as from Rudolphi's description. The 
two organs are separated by an aponeurotic membrane ; the external 
one lies superficially under the skin, the deeper one immediately upon 
the muscles ; the nerves of the external organ are derived from the 
nervus vagus, which runs under the aponeurosis, and sends branches 
through it to reach the organ. The nerves of the internal organ are 
derived from the intercostal nerves, and are very minute. The external 
organ consists of very small lozenge-shaped cells, which it requires a 
lens to see : the internal one seems also to be formed of cells. Rudolphi 
calls the substance of the internal organ flaky .f 

The effects produced by the electric fishes on animals are perfectly 
analogous to electric discharges. The shock from the torpedo when 
the fish is touched with the hand reaches to the upper arm. The gym- 
notus will attack and paralyze horses even, as has been so well described 
by Humboldt. Substances which are conductors or non-conductors of 
electricity bear the same relation to the influence communicated by 
the torpedo and the gymnotus, which are the only electric fishes that 
have been hitherto accurately examined with reference to their electric 
action ; and a shock is propagated through a chain of several persons 
when those at the extremities of the chain touch the fish. Walsh has 


indeed obtained sparks by conducting the discharge of the gymnotus 


through a strip of tin foil which was gummed to a piece of glass and cut 
through in the middle ; it was at the line of the section that Walsh, 
with Pringle, Magellan, and Ingenhouss, saw the spark pass from one 
half of the foil to the other. % Fahlenberg has repeated this experiment 
with the same result, while the fish was exposed to the air. § Not the 
slightest action had ever been observed to be produced either by the 

* Rudolphi in den Abhandlungen der Academie von Berlin, 1820, 1821, p. 229, 

tab. i. ii. 

f Rudolphi in Abhandh der Acad, zu Berlin, 1824. 

% Journ. de Phys. 1776, Oct. 331. 

Vetensk. Acad. Abhand. 1801, ii. p. 122. 




rpedo or by the gymnotus, on the electrometer, by Humboldt and 
^onpjand, Gay Lussac, or Sir H. Davy. But Dr. John Davy has dis- 
covered that the electric organs of the former fish really have an elec- 

tric action on the galvanometer. 



also ascertained clearly 


,j , o ™-~»~»» L ^i. x/avj aiou ttatci tctlilCU Clearly 

at the electric discharge of the torpedo will render needles magnetic. 

tai^d beCn COnfirmed b ^ L inari,t who, as well as Matteuci, has ob- 
ined sparks, decomposed water, and observed marked deviations of the 
galvanometer at the moment of the discharges.] 

Zaws t which regulate the discharges.— The power of producing the dis- 
charge is quite voluntary, and dependent on the integrity of the nerves 
e organs. The heart may be removed, and the shocks will still be 
communicated for a long time ; but with the destruction of the brain, 
ivision of the nerves going to the organs, the power ceases. The 
es^ ruction of the electric organ of one side does not interrupt the 

!£o 10n ° f the °PP osite or gan- All observers agree, that the electric dis- 
°rge does not take place every time that the fish is touched, but de- 
pends on a voluntary power, so that it is often necessary to irritate the 

sh. Moreover, it would appear that it has the power of determining 
the direction of the discharges ; for when Humboldt and Bonpland laid 

old of the fish, one by the head, the other by the tail, the shock was 
not always felt immediately, and both did not always receive it. Some- 
times the animal struggles when teased, without giving any shock. It 
seems to be itself scarcely sensible of the shocks. In the electric eel 
no motion is observed at the time of the discharge, and in the torpedo 
there is merely a slight motion of the thoracic fins ; while the electric 
fishes are very sensible to the artificial galvanic stimulus applied 

No convulsive motions, however, are produced in the gymno- 
tus, - according to Humboldt's observation, when one of these fishes 
receives a shock from another. 

The electric shock is felt, if the animal is inclined to communicate it, 
by merely touching one surface with a single finger, as well as by ap- 
plying the hand to both surfaces, dorsal and ventral. In either case it 
is a matter of indifference whether the person, who touches the fish, is 
isolated or not. Dr. John Davi 





of the dorsal surface is positive, that of the ventral surface negative ; and 
that unless both surfaces are touched, no shock is felt. 


who had the opportunity of instituting experiments on a great number 
of these fishes, could detect no current by means of the galvanometer, 
when both plates connected with the wires of the instrument were 
placed upon the back, or both upon the belly, 
was connected with the back, the other with the ventral surface, 


* Philos. Trans. 1832. 
t Phil. Trans. 1834. 

-j- Stances de l'Academie des Sciences, Juillet, 1836, 
|| Stances de l'Academie des Sciences, Octob. 1836. 

F 2 






the same side, or one on 



;r "r^" " a current was detected passing 
tl the do sd to the ventral surface, the dorsal surface being postuve, 
u entral ulative. These current,, however, were not perceptible 
2T.T5 o f h body except during the discharges The expert- 
lets of M. Colladon/ who had more than forty torpedos at his dis- 
nosT seem to explain the discrepancy in the statements of different 
*b e 'vers as to the possibility of perceiving the shocks when one surface 

ooserveife a& tv r ' mi u ^ A/r p n n ai q nn obtained with 

only of the body is touched. 

X ce to t ZplTare the flowing. The dorsal surface through- 
out is positive, when it is connected with any part of the ventral sur- 

andTe electric action is weaker the more ^^J1,Z 

from the electric organ. 

face ; 


T "• V „f he tack no effect is produced upon the galvanometer. 
But when the to pots on which J wires are placed are not syntme- 

"he h r they be both on the belly or both on the back a current 
deleted by the" galvanometer, a deviation sometnnes of S>0° or 30 

being produced, the part nearest to the organ positive or nega- 


e eiecuicxij a^^«"' & . - ,.„ 

In many respects the torpedo and gymnotus agree ; in a few they dif- 
Gay Lussac and Humboldt have remarked some interesting points 


of difference. When 

But when 
If the tor- 

discharge takes place, whether the person is isolated or not. 
he is isolated, the contact with the fish must be immediate. 
P do is touched with a piece of metal held in the hand, no .shock is fe 
while the gymnotus transmits its electric discharge through a bar of iron 
leveral fell in length. If a torpedo is laid upon a very th ^ate of 
metal, the hand which holds the plate never perceive, the shock even 
though the fish be irritated by another person who is isolated, and 
though the spasmodic movements of the thoracic fins indicate that 
strong discharges are taking place. If, however, the torpedo, lying on 
a metallic plate, which is held as before with one hand is touched on 
the upper surface with the other hand, a powerful shock is felt in both 
arms The sensation is the same when the fish is between two metal 
mate's the edges of which do not touch each other, and when the hands 
are placed at the same time on the two plates. But when the borders 
of the plates are in contact, the shock ceases entirely to be felt ; the 
circle between the two surfaces of the electric organs is completed by 
the metallic plates, and the new circle formed by bringing the two 
hands in contact with opposite plates, has no effect. 

Electric fishes, which are still vigorous, exert their electric power as 

strongly in the air as in the water. If several persons form the chain 

• bltween the upper and under surfaces of the fish, the shock is not felt 

* Stances de l'Acad. des Sciences, Octob. 1836. 



unless these persons have previously moistened their hands. The dis- 
charge, however, is felt by two persons, who, while grasping the tor- 
pedo with their right hands, complete the circle — not by holding each 
other by the left hands, but by each dipping a small bar of metal into a 
drop of water on an insulated body.* Lastly, it is to be remembered 
that Spallanzani observed, that the torpedo loses its power of giving 
shocks when its skin is removed. [Matteuci, however, states that the 
electric shock of the torpedo is felt when the skin is removed from the 
or gan, and even when slices of the latter are removed. M. Matteuci 
thinks that the electric influence is derived from the brain, and is only 
strengthened in the organs as in a Leyden phial. He found the intensity 
of the shocks diminish in proportion to the number of the nervous fibres 
going to the organ, which he divided. Two grains of muriate of mor- 
phia introduced into the stomach, in ten minutes produce death, 
attended with convulsions and strong electric discharges, 
animal had ceased to give shocks, even when irritated, discharges 


stronger than ordinary, and following the usual course from dorsal to 
ventral surface, were excited by laying bare the brain and touching the 
posterior lobe from which the nerves arise. If, instead of simply touch- 
ing the brain, wounds were inflicted on it in no certain direction, the 
shocks were renewed, but the electric currents followed no constant 
course ; under these circumstances 


M. Matteu 


Electric phenomena in fi 

The electric phenomena of the electric 

fishes are effected by means of special organs. Whether electricity is 
developed in animals by ordinary vital processes is another question. 
Electricity exists in all bodies in a state of equilibrium, and by contact 

of certain bodies can be made evident by being thrown into positive and 
negative states even in living frogs. In the spring before the time of 
breeding, and in the latter cold part of autumn, but not in the summer, 
frogs evince great sensibility to the galvanic stimulus. If at these times 
the leg of a frog, dissected in the usual manner, is laid upon a glass 
plate, and the crural nerve touched with a plate of zinc held in one 
hand, while the experimenter touches the leg with a finger of the other 
hand, a strong contraction of the muscles ensues every time the circle 
is thus closed; if copper is used in place of zinc, the result is the 
same, but the contraction is not so strong. I found also that if the 
nerve of the frog's leg was laid upon a plate of zinc, and the nerve 
and muscles of the leg then connected by a piece of the flesh of a frog, a 
contraction of the muscles was always produced. The effect was indeed 
the same, when the zinc plate on which the nerve lay was approxi- 
mated to the surface of the limb. Lastly, having removed the thigh, 

See Gay Lussac et Humboldt, Ann. de Chemie, 65, 15. 

A. v. Humboldt's Reise 

in die ;Equinoctialgegenden des neuen Continents. 3 Theil, pp. 295—324. Treviranus 
Biolog. vi. 144—180. 

I :l< 

i i 




leaving merely the crural nerve attached to the leg, I brought this nerve, 
by means of an isolating rod, near the surface of the limb, and made it 
touch the moist skin of the leg; contraction of the muscles then took place 
both at the moment of contact and also at the moment that the nerve 
was separated from the surface of the limb. This experiment, which 
Humboldt had already performed in a different manner, is extremely re- 
markable, and is the simplest galvanic experiment which can be made on 
a frog. No metal is required, but the leg with the nerve hanging from 
it must lie upon a glass plate. The nerve is raised gently upon a quill, 
and turned back so as to touch merely the leg ; a contraction of the leg, 


then, sometimes occurs. Another experiment, which I have made, is 
more complicated ; it consists in closing the circle between the nerve of 
the dissected thigh and the surface of the leg, by means of two living 
frogs or two frogs' legs ; even portions of a dead and putrefying frog may 
be used to complete the circle. If the nerve which hangs to the upper 
extremity of the frog's leg is laid in a saucer containing blood or water, 
it matters not which, and the fluid in the saucer is brought into connec- 
tion with the muscles of the thigh by means of a copper wire, a muscular 
contraction is produced, equally as well as if the nerve itself and the 
thigh were directly connected by means of a copper wire, or a portion of 
fresh or putrid muscle. In the first experiment, in which I closed the 
circle between the nerve lying on a zinc plate and the leg, by means of 
my own body, I imagined that the contraction produced was excited by 
the electricity of my body. But when I saw that a dead frog or a piece 
of putrid muscle was equally efficient, and that muscular contractions 
could be produced by closing the circle between the ischiadic nerve and 
muscles of the thigh with copper wire and water, I immediately changed 
this opinion. Lastly, the experiment in which, nearly in the same 
manner as Humboldt, I excited muscular contraction by turning back 
the nerve towards the surface of the leg still covered with cuticle, with- 
out any intermediate conductor of metal or muscle, proves that for the 
simplest electric phenomenon on frogs, or separated parts of frogs, the 
mere contact of nerve and muscle, which at their other extremities are 
organically connected, is sufficient, and that the use of conductors of 
metal, or of fresh or putrid muscle, merely strengthens the phenomenon. 
It appears then, either that free electricity is generated in living bodies, 
and that when certain substances come into contact an overflow of this 
electricity takes place and produces muscular contractions, or that the 
mere difference in chemical properties of the nerve and muscle, produces 

an electric tension, while closing the circle restores the electric equilibrium 

and produces the contraction. All the phenomena above described are 
observed in frogs only in the spring before the breeding season, and in the 
cold part of autumn, either on account of the greater excitability or the 
greater accumulation of electricity at those times. 



Explanation of 

From the above experiments it ap- 

all ^h thC dectricit ^ which exists in d ead and living animals, as in 
ten 0, b ° dieS ' is Under certain circumstances thrown into a state of 
trick "' ^ ^ ° ther W ° rdS ' se P arated int0 Positive and negative elec- 

ciid \ ^ the 1Cg ° f the fr0g ' the discnar § e takes P lace wh en the 

c e between the nerve and muscles, which are in different electric 

^tes is c l osed . The thigh of thg frog ^ thig cage acts the ^ rf & 

^ ost delicate electrometer, contraction of the muscles being produced 

y^ the electricity developed in it. It is uncertain whether the different 

ectnc state of the nerve and muscle under these circumstances is a 

6S . U t of tne vital process, or arises merely from the electricity, which 

s ed previously in a quiescent state in these parts, being, as in the 

P enomena of galvanism generally, thrown into a state of tension by 

e contact of heterogeneous substances 

it cannot be ascertained 


w ether a dead nerve and muscle are susceptible of this tension ; for, 
even if it were produced in them, the dead muscle having lost its 
contractility would not indicate it. Much that is fabulous has been 
a Jeged concerning the developement of electricity during the vital 
Process. The truth is, that the electric phenomena, which are mani- 
ested in animals independent of friction, are very feeble ; although it 
oes not appear possible for the various chemical changes, which take 
place m them, to occur without some developement of electricity. 

All that is known concerning the develope- 
ment of electricity in the human subject under the influence of the 
vital process, is furnished by the researches of Pfaff and Ahrens.* The 
experiments were performed with the aid of a gold-leaf electrometer, 
the persons who were the subjects of the experiments being placed 
upon an insulating stool. The collector plate of a condenser, which was 
screwed upon the electrometer, was touched by the person, while the 
other plate of the condenser communicated with the earth. The re- 
sults obtained are the following : 

1. As a general rule, the kind of electricity evidenced by man in the 
healthy state is the positive. 

2. It seldom exceeds in intensity the electricity excited when cop- 
per, which communicates by a conducting substance with the earth, 
comes in contact with zinc. 

3. Excitable persons of a sanguine temperament have more free 
electricity than indolent persons of a phlegmatic temperament. 

4. The quantity of the electricity is greater in the evening than at 
other periods of the day. 

5. Spirituous drinks increase the quantity of electricity. 


there is no determinate rule for the prevalence of this kind of electri- 


* Meckel's Archiv. iii. 161. 



city. Gardini had found that women manifested negative electricity at 
the time of menstruation, and also during pregnancy. 

7. In the winter, bodies, which are very cold, at first give evidence of 
no electricity; but it gradually becomes manifest as warmth is re- 

8. The body, when perfectly naked, manifests the same phenomenon, 

which is also common to all parts of it. 

9. During the continuance of rheumatic affections, the electricity of 
the body seems to be reduced to zero, and to reappear as the disease sub- 
sides. It appeared to Humboldt,* that rheumatic patients had an 
insulating action on the feeble current produced by a simple galvanic 


Do any vital actions depend on electricity ?— Much has been said 

of the production of several vital actions, particularly those of the 
nerves, by the agency of electricity. But nothing of this kind has been 
demonstrated. Neither Person! nor I have ever been able to detect 
electric currents in the nerves.^ Pouillet at first thought that he had 
perceived electric currents in needles inserted into the flesh in the 
operation of acupuncturation; but he has himself acknowledged his error." 
Having inserted a needle into a diseased or healthy part of the body, 
and taken another needle into the mouth, he connected the conducting 
wires of the galvanometer with the two needles, and perceived several 
times soon afterwards oscillations of the magnetic needle ; but I did 
not perceive this effect on the needle when I repeated the experiment. 
Pouillet, however, imagined that the electricity arose from the oxidation 
of the needles inserted into the flesh ; for a very delicate galvanometer 
will indicate the oxidation of metals. In fact, not the slightest devia- 
tion of the needle took place when the needles employed were formed, 
not of steel, but of a metal which does not easily oxidise, such as platina, 
gold, or silver. In that case it is also possible for oscillation to be 
caused by the end of the needle inserted into the body being heated 
more than the other, which alone, it appears from Seebeck's discovery, 
would be sufficient to develope galvanic electricity in the needle, 

Donni has recently discovered, by means of a very delicate galvano- 
meter, that there is really an electric action between the inner and 
outer surfaces of the skin, which action he attributes to the alkaline 
and acid properties of the secretions. || Matteuci has seen a devia- 
tion of the needle amounting to 15 or 20 degrees when the liver and 
stomach of a rabbit were connected with the platinum ends of the wires 
of a delicate galvanometer. He imagines that this action does not de- 

* Humboldt, iiber die gereizte Muskel. und Nervenfaser, i. v. 159. 

-f- Magendie's Journal de Physiol, x. 216. 

t This subject is more particularly discussed in the Book on the Nervous system. 

§ Magendie's Journal de Ph. v. p. 5 

Ann. des Sciences Nat. 1834, Fev 






Pend on the difference of the chemical properties of the secretions, be- 
cause ,t became very feeble, or entirely ceased, after the death of the 

dnima . r» fl^ — . -i. i ^.^ 


ct o n . but he alsQ found that the Mrves ^ not affect t ^ ^ 

eter, even when the current of a galvanic battery is passed through 
em. Hence, even if there were really electric currents in the nerves 

Bellingeri has made 

they would not be detected by the galvanometer. 

some experiments on the electricity of the blood removed from the body 

^ at of the bile, and of the urine, from which he concludes that in inflamec 

ood the electricity is diminished, and that blood retains its electricity 

on g after it has been abstracted from the body.-|- But how desirable it 

would be to prove first the real existence of free electricity in the bloor 

revost and Dumas regard the microscopic flattened particles of the 

°od, consisting of a nucleus and capsule, as pairs of galvanic plates ; 

an Dutrochet even endeavours to prove that the nuclei are negative 

e ectnc, the capsules positive electric. This hypothesis will be refuted 

jn the section on the Blood. Dutrochet's imagined formation of muscu- 

ar nbre from the blood by the agency of electricity, will be shown to 

e equally an error. Several French physiologists, following Hunter, 

bernethy, Prochaska and others, attribute every process in the animal 

ody to electric action. In treating of the nervous system, I shall 

show, however, that although, as appears from my own experiments, 

electric actions can be generated in the nerves, still the mode of action 

of the nerves is wholly different from that of electricity. 

Among modern physiologists, no one has carried the hypothesis of 
electricity being the cause of vital phenomena to a more extravagant 

length than the chemist Meissner.+ With no proofs to support it, he 
advances the following hypothesis. He supposes that, during the 
chemical process of respiration, the blood becomes charged with elec- 
tricity ; that at the same time the electric fluid is distributed through 
the pulmonary nerves and the ganglionic system, and from them is 
communicated to the great nervous centres. He supposes further, that 
the brain, the seat of volition, being thus charged with electricity, ex- 
cites the action of any desired organ by giving an electric spark to the 
corresponding nerve ; that the electric fluid sent to the muscles forms 
an atmosphere around each of the molecules, which by their union in a 
linear form constitute a fibre, and thus forces asunder at their middle 
the muscular fibres, which being firmly united at their extremities, con- 
traction of the muscle is produced, just in the same way as, when several 

* Matteuci, L'Institut. N'. 75. 

1* Experimenta in electricitatem sanguinis, urinae, et bilis, Mem. d. A. d. Tor 
81 — Froriep's Not. 19, 177. 

System der Heilkuude aus den allgemeinsten Naturgesetzen. Wien, 1832. 








threads, with a number of pith balls strung upon them, are tied together 
at both ends, hung upon an electric conductor and electrified, the indi- 
vidual balls and threads are forced asunder, and the two ends of all 
the threads are approximated. Independent of the known fact that 
muscular fibres while contracting do not separate from each other, but 
are thrown into zigzag flexures, there is not one single proof in support 
of all this visionary speculation. Meissner explains by his theory the 
cures effected by the so-called animal magnetism. But it ought first to 
be ascertained whether electricity is really developed in the processes of 
incubation, respiration, &c. 

Pouillet has endeavoured to prove, that during the vegetation of 
plants, an abundance of electricity is developed. Pouillet first investi- 
gated the generation of electricity in the formation of carbonic acid. 
He placed a cylinder of carbon on the plate of a condenser, inflamed 
the upper end of the cylinder, and supported the combustion by a mo- 
derate current of air. In a few moments the condenser was charged 
with negative electricity, while the carbonic acid formed, coming in 
contact at the height of a few inches with a brass plate, which was con- 
nected with the condenser, was found to possess positive electric proper- 

In his experiments on the developement of electricity during ve- 
getation, Pouillet made use of twelve glass vessels from eight to ten inches 
in diameter, which he covered externally for the extent of one or two 
inches near the border with a varnish of gumlac. These vessels he 
placed in two rows on a piece of very dry wood. He then filled them 
with garden-mould, and connected them by metallic wires, which passed 
from the interior of one vessel to that of another, so that the interior of 
all the vessels formed part of one circle. If, now, electricity was deve- 
loped in them, it would be distributed through all the vessels, but would 
be prevented from escaping by the varnish at their margins. He now 
connected the isolated plate of a condenser with one of the vessels bv 
means of a brass wire, while the lower or moveable plate of the con- 
denser communicated with the earth. The apparatus being thus pre- 
pared, some seeds were sown in the earth contained in the vessels. In 
a few days resinous electricity was developed in the vessels, while vitreous 
electricity was detected in the gases formed. This continued until the 
air of the chamber became impregnated with moisture.* These expe- 
riments must be repeated with the necessary modification on incubated 
eggs, and on animals with reference to the formation of carbonic acid 
during respiration. 



Of the generation of 

The temperature of the human body in those internal parts which are 
most easily accessible, such as the mouth and rectum, is 97-7° or 98-6° 

* Aimal. de Chim. et de Phys. 35, 420. 






Ma*™ J hQ tem P. erature of the blo «d is found to be from 100* to 10U° . 
£gh as from 106° to 107°. In the morbus cceruleus 

is defer*.™ o * • r • . , U1UIUUS "eruieus, m which there 

the ZT artenallsatlon of the blood from malformation of the heart 

W insir^l ° f the b ° dy " ° ften S6Veral d ^ eeS l0 ™ «»» « 

t- placed t » "> " T 5 " *" ^"^ Chole ^ a ther — 
' placed m the mouth rises only to 77° or 79". 

bodv in K. nu • ,* ' ' ine tem perature of the 

than d„rin * X \ aCC ° rdl ^ t0 A «tenrieth, 1|° Fahr. lower during sleep 
evenino f Y ' 8nd somewhat lower in the morning than in the 

interior nP^ 7? CHmateS ' ^ D&Vy f ° Und the temperature of the 
he oC ^ 2 ' 7 °-3-6° Fahr. higher than intemperate climates: 

ages I difference of temperature in individuals of different 

This'l m natlVes as wel1 as in P ersons coming from cooler climates, 
villi aSt observat ion is, however, quite opposed to the results of Dou- 
Ule s experiments.* 


collected ,n a "<• ma T aUa ^ hlrdS "~ Tiedemann and Rudolphi have 
mals. n relative t0 the temperature of different ani- 

mannl f ° llowin S is d onved from the more copious table of Tiede- 

The Ox . 






Bat. — Vespertilio noct 


Vespertilio pipistrellus 

-Simia aigula 
Porpoise — Delphinus phocama 
Narwhal.— Monodon monoceros 
Whale — Balaena mysticetus 

has a temperature of from 99° to 1 04° Fahr. 

. 100-40° to 104°. 

. 97° to 98-24°. 
. 99j°. 

. 96-37o to 100-40° 
. 1 00°. 

. 99*46° to 104°. 
. 105°. 

. 102°. 

. 99-30° to 101-30°. 

. 98-60° to 103-60°. 
. 102°. 

. 105° to 106°. 
. 103 86°. 

. 95-90° to 99-50°. 
. 96°. 

. 102° 



From this table it appears, that the heat of the body varies in 
different genera of mammalia ; and it is also seen, that there 


is no 

la in 

remarkable difference between the cetacea and the other mammali 
respect to their temperature 

The temperature of the body in birds seems, from the following 

* Froriep's Notizen, N. 686. 

+ Tiedemaim's Physiologie, i. p. 454.-The English translation, p. 234. 














table, which is also taken from Tiedemann, to be, almost without excep- 
tion, higher than in man and mammalia. 

The gull. — Larus 

has a temperature of 100° Fahr. 

White game. — Tetrao albus 

Common cock 

Common hen 


Anas, different species, 

Bearded vulture. — Vultur barbatus 

Falco, different species, 
Raven.— Corvus corax 
Fringilla, different species, 
Great titmouse. — Parus major 
Hirundo lagopus 


102-99° to 103-78°. 
102-99° to 109-94°. 
106*70° to 109-58°. 
106° to 111°. 


104-50° to 109-74°. 

105-99° to 109-23°. 

107° to 111-25°. 


Production of animal heat in old age and early lift 

Edwards found 

the power of generating heat to be less active in old people. It was 
$hown by the experiments of Autenrieth and Schultz,* that the embryo 
of mammalia owes its heat to the mother, and loses it when removed 
from the uterus. The same rapid diminution of temperature was ob- 

served by M 

in the new-born young of most carnivorous 

and rodent animals when they were removed from the parent, the tem- 
perature of the atmosphere being between 50° and 53|° Fahr. ; whereas, 
while lying close to the body of the mother, their temperature was only 
2 or 3 degrees lower than hers. The same law applies to the young of 
birds. Young sparrows, a week after they are hatched, have, while in 
the nest, a temperature of 95° to 97° ; but, when they are taken from 
the nest, their temperature falls in one hour to 66^°, the temperature 
of the atmosphere being at the time 62^°. Other experiments, which 

id, showed that the want of feathers is not the 
cooling.f It appears from his investigations, 

M. Edwards institut 
cause of this rapid 

that several kinds of mammiferous animals are born in a much less 
perfectly developed condition than others ; that the young of dogs, cats, 
and rabbits, for example, are far inferior in the power of generating 
heat, to the young of other animals which are not born blind. In four- 
teen days this defect is removed, and they have then reached the stage 
at which the young of these other animals are born.J The need of ex- 
ternal warmth to keep up the temperature of new-born children is well 
known ; it is not less necessary, indeed, than to the young of carnivo- 
rous and rodent animals. The statistical researches of M. Edwards have 
shown that the want of external warmth is a much more frequent cause 
of death in new-born children than has been hitherto supposed. § 

* Experimenta circa calorem foetus et sanguinem. Tub. 1799. 
f Froriep's Notizen, 151.— Edwards, On the Influence of Physical Agents on Life, 
translated by Drs. Hodgkin and Fisher, p. 117 — 121. 

% Compare Legallois , Meckel's Archiv. iii. 454. § Edwards, loc. citat. 



Effects of 

animals. — Hyb 

The generation of 

aionc m adult warm-blooded animals is in a certain measure independent 
or external temperature : this independence, however, varies in degree 
according to the geographical distribution, and the internal vital con- 

itions of the animal; hence the migrations of many animals with th 

c ange of the seasons. But it appears from Captain Parry's observa- 

H>ns, that the mammiferous animals of polar regions will support the 

emperature at which mercury freezes, namely, —40° Fahr., or even 

J temperature as low as —51° Fahr* There are some mammalia, 

owever, namely, the hybernating animals— the marmot, rellmouse, 

amster, hedgehog, bat, beaver, and bear,— which, when the external 

emperature is not low, maintain an animal heat which does not differ 

iom that of other mammalia, but lose this heat when the surrounding 

a mosphere becomes very cold, and fall into a state of torpor or 

asphyxia, and several of them even become frozen at 10° or 6J Fahr. 

he beaver and bear hybernate but imperfectly. 

The phenomena of hybernation have been studied more especially 

external temperature is 


As long as the 

as high as 50° or 521°, the phenomena of 

ybernation are not induced : the hazel-mouse, indeed, retains, Saissyt 

says, all its vivacity at 43-1 


Saissy also 


Spallanzani had stated the contrary. 

external temperature, and neither commences later nor ceases earlier 
when the winter is late and the spring early. Pallas induced sleep in 
marmots during summer by placing them in an ice-house ; and Saissy 
succeeded in the same manner in producing this state in hedgehogs, 

myoxus glis. In the depth of winter these animals 

awake, if placed in a temperature of 524° or 541°. 

myoxus avellanarius — throughout the 

and rellmice 


winter in a room, the temperature of which was never lower than 50° 
Fahr., generally was between 59° and 63|°, and sometimes was as high 
as 701°, without the animals being roused from their torpid state. He 
hence concludes that neither external cold nor the necessity of external 
warmth for the maintenance of internal heat is the cause of hyberna- 
tion. But that external temperature has a great influence on hyberna- 
tion is evident from Berthold's own experiments ; for the animals which 
he kept in a warm room were much more easily roused than those which 
were exposed to the cold of the season : the animals exposed to the 
cold air fell into the state of hybernation in October; while those which 
were kept in the room, did not become torpid before the middle of 
December; and when the torpor of these latter animals was not com- 

* See Tiedemann, loc. cit. pp. 461. 466. Translation, p. 236. 
t Mem. de Turin, 1810—12. Meckel's Archiv. fur Physiol, iii. p 


% Mailer's Archiv. 1837, p. 67. 





plete, it was always rendered deeper by a sudden change from mild to 

severe weather, and vice versa.] 

The temperature of the animals during hybernation, although it falls 
proportionately with the temperature of the surrounding air, still is 4§ 
Fahr higher than it. Respiration is kept up, though slowly and almost 
imperceptibly. The marmot during hybernation breathes seven or 
eiiht times in a minute, the hedgehog four or five times, the great 
dormouse nine or ten times in the same period. During the state of the 
deepest torpor, however, respiration ceases entirely ; and the animals 
may" then, if Spallanzani's observation is correct, be f^^^ 

" Saissy found that until this last state 

nitv in an irrespirable gas. . „ - . 

Ls, they continue to remove the oxygen from the £*»J 
of oxygen consumed decreasing as their temperature falls , but i sUll 
continues, together with the exhalation of carbonic acid , ^^J 
oxvaen remains in the air; whereas animals which do not hybeinate, 
uTL Tbbits, rats, and sparrows, die when they have consumed a 
small portion only of the oxygen of the air contained in the ves eh, 
M Prunelle states that the arterial blood of the bat is less bright ra 
colour during hybernation. With respect to the circulation, Saissy 
found that, at the commencement and towards the termination of the 
state of hybernation, the motion of the blood is extremely slow ; and 
tat while the torpor is complete, the capillaries of the extreme parts 
ar almost empty! and the large vessels only half distended I was 
ony in the larger trunks of the chest and abdomen that an undulatory 
moLn of the blood was still observable. In the bat during hybema- 
Znle heart beats, according to Prunelle, only fift y or « ^ve time 
in the minute, while ordinarily it beats about two hundred times in the 
anoint erva Sensibility, and the irritability of the muscles, as tested 
b7mechanical or galvanic stimulants, are diminished, but are not entire- 
I" : a nt g except during the state of the deepest torpor This entire 
absence of sensibility and irritability of the muscles has been witnessed 
bv Saissy a few times only in hedgehogs and marmots. The secretions 
do not wholly cease ; for Prunelle found that bats lost jfr of their weight 
between the 19th of February and the 12th of March. . 

Saissy states moreover that the blood of the marmot and hedgehog is 
remarkable for the small quantity of fibrin and albumen which it con- 

tains ; 

that the bile is sweetish, but that the fat is unchanged- 


ing to Prunelle and Tiedemann,* an apparently glandular but really fatty 
mass forms in the neck and anterior mediastinum before hybernation : 


thymus gland. 


* Meckel's Archiv. t. i. p. 481. 

± N. act. ac. csss. nat. cur. t. xiii. p. 1 

f Ibid. iii. 151, 152 




pared to the internal carotid, passing through the stapes of the tym- 
panum in the following genera, Vespertilio, Erinaceus, Sorex^ Talpa, 
Hypudaeus, Georhychus (Lemmus), Myoxus, Mus, Cricetus, Dipus, 
leriones, Arctomys, and Sciurus; all of which animals,, Otto says, are 
Object to a state of more or less complete hybernation. The assertion 
Mangilr, that the cerebral vessels are remarkably small in hybernat- 
n g animals, is denied most expressly by Otto, who also did not observe 
e large size of the nerves of the superficial parts, which was spoken 
by Saissy. It is generally known that, during hybernation, a part of 
e fat formed in the autumn is consumed to nourish the bodj. But 
e experiments of Pallas, who produced hybernation during the height 


°* summer by means of artificial cold, prove the incorrectness of the 
theory, which supposes that it is the accumulation of fat, and the enlarge- 
ment of the glands in the chest and neck during the autumn, which 
J nduce hybernation, by exerting pressure upon the respiratory nerves, 
^he spinal cord is very short in the hedgehog ; but this is not a general 
character of hybernating animals.* 

Effects of external heat on the temperature of warm-blooded animals, 
y- the temperature of the atmosphere, in which a mammiferous animal 
ls placed, exceeds the natural heat of its body, a slight elevation takes 
place in the temperature of the animal's body, not however in propor- 
tion to the elevation of the external temperature. Experiments have 
been instituted by Duntze,f Fordyce, Banks, Blagden,^ and Delaroche,, 
and Berger, to ascertain the effect of increased external heat on the 
temperature of the body. Sir C. Blagden and others supported a tem- 
perature between 198° and 211° Fahr. in a dry air for several minutes; 
[in a subsequent experiment Blagden himself remained eight minutes 

in a temperature of 260°;] Delaroche and Berger observed an eleva- 
tion of temperature of a few degrees only in rabbits exposed to a heat 
varying from 122° to 194° Fahr. In birds also the heat of the body 
did not rise commensurately with that of the surrounding atmo- 
sphere: it did not suffer an elevation of more than 11 or 12 degrees, 
fhis power of maintaining nearly their original temperature when ex- 
posed to great external heat, is owing to the cooling effect of the in- 

The principal treatises on hybernation are : — Saissy, Recherches experimen tales 
anatomiques sur la physique des animaux mammiferes hybernans ; Paris et Lyon, 
lo08; iibersetzt von Nasse. ReiFs Archiv. fiir Physiol, t. xii. p. 293. Saissy, 
M6m. de Turin, 1810—1812. Meckel's Archiv. fur Physiol, t. iii. Mangili tiber den 
Winterschlaf, in ReiFs Archiv. Bd. 8. Prunelle, Recherches sur les phenomenes et 
sur les causes du sommeil hivernal : Ann. du Mus. t. xviii. Gilbert's Annalen, Bd. 
40 u. 41. 

+ Exp. calorem animalium spectantia. Lugd. Bat. 1754. 

t Philos. Transact. 1775, v. 65. 

Delaroche and Berger, Exp. sur les effects qu'une forte chaleur produit dans 
l'economie animale. Paris, 1806. Journal d, Phys. 71. ReiFs Archiv. 12. 370. 









, - i • i„ cffor under these circumstances. 

-sea ^TirlT tJs etpZat ""by the *— - * 
^eatytXl^l the heated atmosphere is at the £. « 

SuU with moisture which ^^^JvZ^ that 
temperature of the animals me. 4, 7, even 9 d*«»J« e 
of L surrounding atmosphere It ^'J* ^J^ in ° a dry 
that the increased from the surface o t > 

heat does hot arise solely *•£*£*£££, ^ 

heat here excites an f»^?»*^J^ „„' internal causes ; and in 

rnyf^rrrilSly^mereJfrom Us being dry, and 

from perspiration being obstructed. 

It has been often said, but 

no power of 

Temperature oj «^™~ . lg have themselves no power ot 

incorrectly ^^^^^^ «■* *~ f "'" 
generating heat^but den ^ and .^ ^ researches 

ing medium. Wl * '^^ ^Tiedemann, have proved that the 

° fDr -^^— alLgh it generally falls with that of 
temperature ot tnese anuueu , & „ AVPrthe i eS s mostly two or 

the surrounding medium to a certain point, »£*££,„ Ls also 

m „re degrees higher; and tha ^ ugh then t ^ ^ ^ 

with that of the medtmn, yet -. «£ P^ ^ ^^^^ temperat „ re . 

and at great degrees of heat even '° Wbia the tem . 

From Czermaclfs.exper.mentsa appear^ r ^ 

peratnre of the body exceeds that of *e ^ ^ 

Thus the temperature of the body^ ^P ^ temperature rf the a , r 

<? CCX.O Tn wafpr. 

tli^t of the air was 55 1°> — *™~ — * p^ 

that oi uie a ^ temperature of 55 

was 63§V~ and was 65 in water oi <* v _ _ ^^ 

In water, 

was 63r,-and was bo u> » « r was 48 „ . in 

of which the temperature was44 , *. te P ^^ ^ ^ 

„lr of 54i". was 464". Czei macK mm. r 

air of 54i% was 46 i " ^^ e tem perature of the body differs most from 
pen* are those m which .the te P rf ^^ ^ Dr 

that of the atmosphere to * ext ^ ^ ^ ^ rf g 

Davy t also found the tempe a ternpe rature of a testudo 

Fab,, and 89- 9 • ■» a, of 82 94 ^^ ^ ^ ^ ^ 
my das was only 84 , tne ne«* 
8 /. when the heat of the *"**££ „L„ the water was frozen, a 

Tiedemannt observed that ^ night ^ fc ^ m _ 

frog had a temperature of 33 ». , , ow terape . 

frozen. Frogs «^«£££L. „f elation. Fishes also, it 
f ature in a great external Heat oy ^ ^^ Br0USS0Ilet( an( l 

appeal s »«"' »- ~- r — 

.■■«*- Af rVermack on the temperature of reptiles in 
* See the numerous experiments of Cz ^ ac ph - k mld M athematik, 3 Bd. 

Baumgaertner's and ^^^TtvZ. 1814. Jameson's Journal, v. xix. 


;rtner s aim *jw» h 4 j ame son T s Journa 

+ „ Noli, i^W- . * — ^ Md LaM> p , 240 . 

riftmann. Physiol, u Iiansiauim vy 

Tiedemann, Physiol, i. 






surro ^r haVe a temperature one or two Agrees higher than that of the 

hr. ; in the eel 1$> ; in the carp lf>. Despretz found the 

surro Unding water . In smal] fisheg Broussonet found the djfference of 

gree ruo'p f W6en ?"* b ° dieS a " d the Water t0 be from A <* a de- 
^emperature of two carp to be 58«» Fahr., of two tench 52? Fahr.; the 

taineH I" 6 f ^ SUrroundin g water bein g 51 1° Fahr. Dr. Davy ascer- 
a that the temperature of a shark was 77° Fahr. when the tem- 
perature of the sea was 42f ° Fahr. 


He finds that the 

abs e animalS haVe bCen instituted ^ Berthold.* „ e mms mat me 

tn enCe .° r existen ce of a great difference between the temperature of 

iese animals, and that of the medium, depends wholly on the circum- 

ance of the temperature of the medium having been stationary for 

some time, or having recently become elevated or lowered ; for, if the 

^emperature of the medium has changed, a considerable time is required 

* t i e heat of their bodies to undergo a corresponding change. «. w «- 

low S ° UrCe ° f err ° r ' Berthold found that amphibia had generally a 

^ower temperature than the surrounding air, which arose from the cooi- 
ng effect of evaporation. In water, frogs had the same temperature as 
e water. During the act of copulation, the frogs had a temperature £> to 
* • or |° to i|° Fahr. higher than that of the water. Reptiles, when 
e external temperature is moderate or rather elevated, have a heat h" 

10 14.° Po^ M t~:_i .i . _ 7 + 



Pallas t 

some cold-blooded animals also present the phenomenon of hyberna- 
fon. Franklin relates, that many fishes, when laid upon the ice be- 
came instantly torpid, but recovered again after several hours or days 
It has, however, been frequently asserted, that fishes continue to live in 
ice, and that the water around them is not frozen.f 
that crucians (cyprinus carassius) are restored to life „„ _ „,„«« 
of lakes in Siberia, which were frozen to the bottom, and mentions a 
smnlar fact observed by Bell, namely the revival of gold-fishes from 
ozen water. Reptiles become torpid not only during winter, at the 
^ommencement of which they bury themselves, but during summer also, 

a *1! J ^ !f S * In the dr y season re P tn es bury themselves and fall into 

r tQ hyb ernat j on) f rom w hi c h they recover in the rainy 

Humboldt has observed some very interesting facts of this kind, 
warm-blooded animals there is only one known instance of this sum- 

a state similai 



mer sleep ; that is in the tanrec, 



Some complete observations on 

e temperature of invertebrate animals are still wanted, but the facts 

Neue Versuche iiber die Temperatur der Kaltbltitigen Thi 

Mullep's Archiv. 1836, Jahresbericht, p. cxix. 

t Jahresbericht der Schwed. Acad, iibersetzt von J. Miiller, 1824. 

ere. Gotting, 1835. 

In Rudolphi's Grundriss der Physiologie, i, p. 176, 







that are known prove that their temperature, like that of the other 
cold-blooded animals, varies with the temperature of the medium ; but 
that it may nevertheless, even in insects, be a degree or two higher or 
lower than the external temperature is evident from the experiments of 


In the 




ant-hills a very much higher temperature has been observed.* 
river crawfish, Rudolphi saw the thermometer, which in the water was 
at 52 i0 , rise to 54|°, and even to 59° F. Similar evidences of inde- 
pendent heat, though less considerable, have been observed in the mol- 
lusca.t In snails the temperature is two degrees higher than that of 


the medium. 

The insects and mollusca, of temperate and cold climates at least, are 
known, with certainty, to be subject to hybernation. Some of Jthe 
lower animals seem to require a pretty high external temperature ' 

instance of the small snail,— the cyclostomum thermale Ranzani,— which 
lives in the hot springs of Abano, the temperature of which is 83f " ™ 
appears extraordinary. Rudolphi saw these animals move briskly even 
in water of 99^° F. But the entozoa of man and mammalia live in an 
equal, those of birds in a still higher temperature. Rudolphi remarks, 
that the entozoa of warm-blooded animals become torpid in the cold, but 
are a°-ain revived when placed in warm water; while the entozoa of cold- 
blooded animals bear a low as well as a. high temperature. 

The hybernation of snails has been described by Gaspard ; durin 
this state the heart, he says, ceases to beat, respiration is no longer 
carried on, and the tentacula, if cut off, are not reproduced. These 
animals also fall into a summer sleep when the heat is great ; but, m 
the summer sleep, respiration, the heart's action, and the reproductive 

" Sources of animal heat— I now proceed to inquire what are the pro- 
cesses by which heat is generated in the animal body. The first point 
of interest in this inquiry is the difference of temperature of different 
parts of the body. The temperature is lower, the further removed the 
part is from the centre of the body ; thus, in the human subject, a ther- 
mometer placed in the axilla stood at 98° F. at the loins it indicated a 
temperature of 961°, on the thigh 94°, on the leg 93° or 91°, on the sole 
of the foot 90°.§ Dr. J. Davy found the temperature of the rectum, in 
several experiments, somewhat higher than that of the brain ; this ap- 
pears extraordinary, and probably arose from some error of observation. 
Dr. Davy's experiments on the temperature of the different kinds of 
blood are very interesting. Eleven experiments were instituted on sheep 


* See note at end of Prolegomena. • . 

t An account of the different observations relative to this snbject will be found m 
Rudolphi's Physiolog. 179, in Treviranus, Biologie, 5-20, and in Tiedemann s 
Physiol. 476 ; Translation, p. 244. * Meckel's Archiv. 8. 

§ Dr. J. Davy, Phil. Transact. 1814. Meckel's Archiv. n, p. 312. 



ai > oxen ; and from the mean of these experiments it would appear that 
6 temperature of arterial blood is about 1° or 1|° R higher than that 
venous blood.* Mayerf found the temperature of the blood of the 
jugular vein to be from 1° to & R. or from 2|° to <*# F. lower than that 
the blood of the carotid ; but he could not discover the difference of 
J-mperature of the blood of the two sides of the heart, which is spoken 

y Davy. Saissy has made similar observations in livbernatin*? 
animals. fo 

heory of the production of heat in respiration. — According to the 
leory of respiration, invented by Lavoisier and Laplace, and adopted 
y most modern chemists, the oxygen of the atmosphere combines in 
the lungs with carbon of the blood, and is expired in the form of car- 
onic acid ; and if more oxygen disappears from the atmosphere than is 
accounted for by the carbonic acid expired, it is supposed that this por- 
tion of the oxygen which does not go to form carbonic acid, unites with 
lydrogen in the blood and forms water, which is exhaled. Admitting 
t iese hypotheses, it might be imagined that the source of animal heat 
Was the caloric developed during the combination of the oxygen with 
the carbon and hydrogen in the lungs. To render this more probable, 
and to explain more easily the distribution of the caloric, when deve- 
°Ped, through the body, Dr. Crawford $ stated, that arterial blood has 
a greater capacity for caloric than venous blood, about in the proportion 
of U-5 to 10. Thus he supposed, that the caloric developed in the 
un gs at first served to maintain the temperature of the arterial blood, 
and that afterwards, during the conversion of this arterial blood into 
venous blood in all parts of the body, the heat, before latent in the 
arterial blood, was set free. Dr. J. Davy has, however, shown, that the 

capacity of the two kinds of blood for caloric differs, either not at all 
or only very slightly, as in the proportion of 10 to 10-1 1. 

But, supposing that Lavoisier's theory of respiration is correct, the 
amount of caloric that can be generated by the respiratory process may 
be ascertained by direct calculation. This calculation has been made by 
Dulong and Despretz. Dulong introduced different mammiferous ani- 
mals, carnivorous as well as herbivorous, into a receiver, in which the 


n ges produced in the air by respiration, and the volume of the different 
Products, could be determined, at the same time that the amount of 
caloric lost by the animal could be ascertained. Dulong found, that all 
animals extracted from the air more oxygen than was accounted for by the 
carbonic acid which they exhaled. In herbivorous animals, the oxygen 
tlUs Iost amounted on an average only to -& of the whole quantity of 

Uavy. Tentamen experimentale de sanguine. Edinb. 1814. Meckel's A rchi v. i. 
10 $>. Phil. Transact. 1814. f Meckel's Archiv. iii. 337. 

* Dr. Crawford, on Animal heat. Versuche und Beobachtunffen iiber die War- 
der Thiere. 



Leipzic, 1799. 







the oxygen extracted from the air ; in carnivorous animals, the maxi- 
mum quantity of this oxygen, which was not converted into carbonic 
acid, was §, the minimum £, of the whole amount of oxygen consumed. 
If now it be admitted, that, by the conversion of the oxygen into carbonic 
acid during respiration the same quantity of caloric is developed as 
Laplace and Lavoisier found to be produced by the combustion of carbon 
in oxygen gas, it will be found by calculation that only T \ of the heat 
that is lost during a given time by herbivorous animals, and % of that 
which carnivorous animals lose in the same space of time, can be thus 
accounted for. Again, admitting that the oxygen, which is converted 
intocarbo nic acid, is consumed in forming water by uniting with hydro- 
gen, and that as much caloric is thus generated as would be developed 
during the combustion of equal quantities of oxygen and hydrogen 

still the whole quantity of caloric produced by the combination of 
carbon and hydrogen with the oxygen, would amount only to from 
3 to a of that which is developed during the same space of time 
by ca/nivorous as well as herbivorous animals.* 

Despretz placed animals in a vessel surrounded with water; an un- 
interrupted current of air to and from the vessel was maintained, and 
the volume and composition of the air both before and after the experi- 
ment which was continued \\ or 2 hours, as well as the increase in the 
temperature of the surrounding water, were ascertained : by tins means 
he found that the heat, which would have been generated in the respira- 
tory process according to Lavoisier's theory, would have accounted for 
from 0-76 to 0-91 of that which the animals really gave out during the 

same time.t .„,,•! ^^^ 

From these experiments it results, that, even if the chemical theoiy 

of respiration is adopted, there must be still some other source of 
animal heat. But it is exceedingly improbable that the water exhaled 
from the lungs is formed during the respiratory process by the union ot 
its elements ; it is much more probable that a part of the oxygen is 
retained by the blood : the heat produced by the process of respiration, 
therefore, can be estimated as being derived only from the union of the 
oxygen and carbon, and the heat thus generated would, according to 
Dulong, amount in herbivora to T V only, and in carnivora to \ only of 
the heat really developed in the body. Besides, it is at present merely 
an hypothesis that the oxygen of the atmosphere unites with the car- 
bon in the lungs to form carbonic acid; although new facts render it 
exceedingly improbable, that the carbonic acid exists already formed in 
the venous blood, and is merely exhaled in the lungs, while the oxygen 
combines with the blood. According to this latter view, which would 


* Berzelius, im Schwedischen Jahresbericht ; Boun, 1824, p. 67. 
Journal fftr Chemie und Physik. N. R. Bd. 8. S. 505 

t Gmelin's Chemie, t. iv. p. 1523. Ann. d. Cmm. et de Phys. 26, 338. 

See also Neues 



explain the phenomena equally well, the oxygen combines with the carbon 
*n the course of the circulation, and thus imparts to the blood a higher 
temperature. Wherever the carbonic acid is formed,— whether in the 
ungs or in the blood,— the oxygen inspired would in either case be the 
immediate source of its formati 

ion, and respiration might be regarded 

as e cau se, mediate or immediate, of the developement of animal heat ; 
and, adopting the results obtained by Dulong, it might be admitted that 
ln erDlv «ra T tj., in carnivora |, of the animal heat is generated by respi- 
ration. This being conceded, it would be easy to explain the want of per- 
ceptible independent heat in the embryo, in which no oxygen is inspired ; 




»mes a temperature some degrees lower than natural, as well as the 
small degree of independent heat possessed by cold-blooded animals, (in 
which only a part of the blood is aerated, as in reptiles, or in which 
respiration is performed only by means of the air dissolved in water, and 
is consequently less perfect,) might then be likewise easily accounted for. 

o put the chemical theory of animal heat to a decided test, experiments 
must be instituted on the plan of those of Dulong and Despretz, but on 
cold-blooded in place of warm-blooded animals, to ascertain whether, calcu- 
ating from the changes produced in the air by respiration, the quantity 
of caloric generated by the chemical process would not be too large, 
compared with the very small quantity of heat really evolved by the 
former animals. This is an interesting problem for chemical inquiry. 


There must be other 

sources of animal heat, besides respiration. Some physiologists, and 
among them Professor von Walther and Dr. Paris, have thought to find 
a principal source of animal heat in the different secreting pro- 
cesses, in which fluids having a less capacity for caloric than the 
blood are separated from the latter fluid, and caloric before latent 
thereby rendered sensible. According to Dr. Crawford, the capacity of 
milk for caloric is less than that of the blood. Dr. Paris* estimates the 
capacity of urine for caloric at 0-777, that of arterial blood at 1-003. 
Ahese results are directly opposed to those obtained by Dr. Nasse, who 
ound no difference, as regards their capacity for caloric, between the 
different secretions and water ; and Dr. Davy detected scarcely any dif- 
ference in this respect between the blood and water. M. Pouillett has 
directed attention to another source of heat in the vital processes. All 
solid bodies, inorganic as well as organic, undergo an elevation of tem- 
perature when moistened with different fluids. This elevation of tempe- 
rature is much greater in organic substances ; in several cases 
Pouillet found that it amounted to from 11° to 18° of Fahrenheit, 


London Med. and Physic. Journal. 21. 1809. Meckel's Archiv. ii. 308 
t Ann. Chem, Phys. 20, 141. Meckel's Archiv. viii, 233. 




The solution of the food by the fluids of the stomach might be taken as 
on example, and perhaps the slight increase of heat during digestion 
might be thus explained. But a more considerable and more general 
source of animal heat is undoubtedly to be sought in the organic pro- 
cesses, in which by the operation of the organising forces on the organic 
matter heat is generated not in one, but in every organ of the body : 
hence it is, that in cases of long fasting, in which the separation of the 
old matter continues, but not the organisation of new matter, the tem- 
perature of the body, according to Marline, falls considerably, to the 
extent even of several degrees, although at the same time the source of 
caloric in the formation of carbonic acid remains. In inflammation the 
flow of blood to the part is increased, and the temperature is at the same 
time elevated; but Dr. J. Thomson* thinks that it never rises higher than 
the temperature of the blood in the great vessels. Muscular exertion 
and febrile irritation also cause elevation of temperature ; while the de- 
pression of vital energy in nervous affections, and in rigors, causes the 
temperature of the body to fall, although respiration is unaffected. Dr. 
Currief found the temperature in the palm of the hand during syncope 

to be as low as 63° F. XT . „ 

Influence of the nerves in the generation of heat— Now, since all organic 
processes are chiefly dependent on the influence exerted by the nerves 
on the organic matter of the body, it cannot appear wonderful if the 
reciprocal action between the organs and the nerves is a main source of 
animal heat. The experiments of Brodie, Chaussat and others, have 
proved this. Elliot and Home have observed, that, after division of the 
Uves of a limb, its temperature falls, and all observers confirm this 
result in the case of the nervus vagus. The diminution of temperature 
is detectible by a thermometer ; the mere sensation of cold after injury 
to the nerves of a limb must not be confounded with it. Mr. Ear let 
found the temperature of the hand of a paralysed arm to be 70- Fahr., 
while that of the sound side had a temperature of 92' Fahr. On electri- 
fying the limb, the temperature rose to 77°i In another case the tem- 
perature of the paralysed finger was 56" Fahr. while that of the unaf- 
fected hand was 62°. m . 

Brodie§ having killed an animal, either by decapitating it, by dividing 

its medulla oblongata, by destroying its brain, or by poisoning it with 
Worara poison, kept up artificial respiration, and found that the action 
of the heart continued, and that the blood became arterialised in the lungs 

* Lectures on Inflammation. Edinb. 1813, p. 46. 



Leipzic, Bd. i. p. 267. 

Currie on Cold Affusion. 

"Lie, in Med. Chirurg. Transact, vii. p. 173. Meckel's Arch**, m. p. 419. See 
also Yelloly in Med. Chir. Transact, iii. 

Sir b! Brodie, in Phil. Trans. 1811, 4 5 1812, 378. R«l'« Archiv. 12, 1*7, 199. 




as during life, but that the heat of the body was not maintained; 
indeed, it became cold more rapidly than a body in which artificial 
respiration was not kept up, being cooled by the air forced into the 
un gs. Dr. Marshall Hall,* however, observed the very contrary of 
ls ; he found that a decapitated animal retained its warmth longer, 
when artificial respiration was performed. The results obtained by Le- 

f also, do not exactly agree with those of Brodie's experiments ; 

e gaIlois found that every impediment to respiration, whether from the 

animal being fixed upon its back, or from the air which it breathes 

ei ng rarefied or mixed with nitrogen or carbonic acid, is attended with 

*\ diminution °^ temperature; that even the inflation of the lungs with 

air ? by impeding the process of respiration, causes diminution of the heat 

fc he body, and that the greatest degree of cold always corresponds to 

e smallest consumption of oxygen. Emmertrj: repeated Brodie's ex- 
periments with poison and artificial respiration, and found a change 
°f temperature of only 6f ° Fahr. in the space of 74 minutes. Wil- 
son Philip^ infers from his own experiments, that artificial respiration, 
en the inflation of the lungs is performed too frequently, cools the 
body very quickly, but that when employed with moderate frequency it 
retards the cooling of the body. Brodie's experiments are, however, 
lor the main point, convincing. He has shown, that living rabbits 
expire 28*22 cubic inches of carbonic acid in half an hour ; that, when 
artificial respiration is kept up in rabbits after death by poisoning, 
or destruction of the medulla oblongata, a quantity of carbonic acid, 
varying from 20-24, or 25-55, to 28-27 cubic inclies, is still exhaled ; 

us, that under these circumstances, the products of respiration are 
nearly the same as ordinarily during life, and that, nevertheless, the 
temperature falls six degrees of Fahrenheit in the course of an hour. || 
The sinking of the temperature of the body, which Legallois stated 
to be constant in animals fastened down upon their back, was not 




on the contrary, Chaussat confirms 

Brodie's observations. After injury of the brain, the temperature fell 
from 104° Fahr. to 75° before death, which occurred in from eleven to 
twenty-two hours. Division of the nervous vagus, which, without 
essentially affecting the chemical process of respiration, produces death, 
according to Legallois, by inducing congestion of the lungs with serum 
or blood, caused the temperature of the body to fall, during a period 


■ ■ 


London Med. Phys. Journal, 32, 1814. See also Brodie, ibid. p. 295. Meckel's 
Archiv. iii. 429, 434. f Ann. Chem. Phys. 4, 1817. Meckel's Archiv. iii. 436. 

t Meckel's Archiv. 1, 184. 

§ Untersuchung. iiber die Gesetz. d. Function, des Lebens iibersetzt. von Sonthei- 
raers. Stuttgardt, 1822. Inquiry into the laws of the vital functions. 

II See Nasse's Remarks on Brodie's experiments in ReiFs Archiv. xii. p. 404. 

f Meckel's Archiv. vii. 282. 








varying between twelve and thirty-six hours, as low as 97° or 98£° 
Fahr. and at last even to 68°. In all these experiments, unfortunately, 
the temperature of the atmospheric air is not mentioned. Injuries of 
the spinal marrow produced more striking effects on the animal heat, 


the higher the seat of the injury ; so that the effects on the generation of 
caloric, like other consequences of lesions of the spinal cord, were 
greater in proportion to the number of nerves arising below the point of 

Chaussat endeavours lastly to prove, that the sympathetic nerve also 
has a great share in the production of animal heat : he found, that after 
injury of the splanchnic nerve, produced in the extirpation of the supra- 
renal capsule through a wound, which, he says, was not very large, (?) 
the temperature gradually fell from 104-88° to 78*8° Fahr. during the 
ten hours which preceded death. Chaussat applied a ligature to the 
aorta of a dog, at the point where it passes through the aortic open- 
ing of the diaphragm, and then examined the temperature of the upper 
and lower half of the animal; he repeated this experiment, and each 
time it appeared that the oesophagus, up to the time of death, had a 
somewhat lower temperature than the rectum. This slight difference is 
attributed by Chaussat to the cooling effect of respiration. Chaussat 
thence inferred that much less influence on the developement of animal 
heat is exerted in the thorax than in the abdomen through the medium 
of the nerves. The diminution of temperature, which ensues on division of 
the nervus vagus, cannot be assumed to prove the contrary, for this nerve 
supplies branches to abdominal as well as to thoracic organs. But 
Chaussat here attributes great importance to indecisive experiments, 
which prove little or nothing, and does not perceive how many objec- 
tions might be made to them. 

Several of the facts which we have mentioned prove, however, that 
the influence of the nerves in the organic processes of the body contri- 
butes greatly to the production of animal heat in other parts than the 
lungs. Berzelius is also of this opinion, which moreover seems to 
derive confirmation from the rapid and momentary increase of temperature, 
sometimes general, at other times quite local, which is observed in states 
of nervous excitement ; from the general increase of warmth of the body, 
sometimes amounting to perspiration, which is excited by passions of 
the mind ; from the sudden rush of heat to the face, which is not a mere 
sensation ; and from the equally rapid diminution of temperature in the 
depressing passions; — all phenomena, however, which might certainly be 
explained by the increased or diminished flow of blood to the part, and 
in some cases also by a change induced in the heart's action. From the 
facts at present known, the inference we deduce is, that elevation of 
temperature takes place in all organic processes, but that it is in part 
determined by the influence exerted on these processes by the nerves. 




. . - -^.^ w ^^vcu tiiat eaui contraction 01 

muscle zs attended with an elevation of its temperature, amounting to 

1 2° Cent, nr 140_ ().,o C„t,_ n,l . . , , & 


2 f° Fahr. They ascertained the temperature of 

7 Part by means of thermo-electric multiplier, a needle composed 

two other needles united at their point being thrust into the part, 

ue the other extremities of the needles were connected with the 

wires of the multiplier.] 

If now the warm-blooded and cold-blooded animals are compared, the 
cause of the difference of temperature in the two may be sought, either 

ne relative intensity of the respiratory process, or of the 
Processes generally. Without referring one phenomenon to another as 
J ts cause, it may be remembered, that in the cold-blooded animals the 
8 |ze of the central portions of the nervous sjstem is smaller in propor- 
tj on to^ the nerves themselves ; that the respiratory process is far less 
active in proportion to the weight of the body ; that the blood of these 
cold-blooded animals contains, according to Prevost and Dumas, less 
coagulable matter; a similar state of the blood being also found by 
aissy in hybernating animals ; and, lastly, that birds and some mam- 
jnaha, the blood of which, according to Prevost and Dumas, contains a 
"JgW quantity of red particles and coagulable matter, also have a 
higher temperature. 




Before all these facts with respect to the 
cause of animal heat were considered, no inquiry with reference to the 
spontaneous diminution of this power of generating heat during hyberna- 
tion, and regarding the causes of this latter phenomenon, could be 
attended with any satisfactory result. In this inquiry the phenomenon 

of hybernation as presented by a few animals must not be considered in 
an isolated manner, but the investigation must be grounded upon the 
fact, that all animals, when the external temperature falls below a 
certain point, become torpid and frozen, without thereby entirely losing 
the faculty of living ; but that the point to which the external tempera- 
ture may be lowered without this state being induced, varies very much 
according to the organisation of the different animals, and their geogra- 
phical distribution. 

1. Man evidences in this respect a very great tenacity of the organic 
powers, since he maintains his proper temperature, under favourable cir- 
cumstances, in all climates in which animals exist, — in the extreme 
north, as well as under the equator. But even man, when deprived of 
necessary covering and acted on by cold, or, in other words, deprived 
of a vital stimulus, falls into a state of torpor, and the more easily when 
his vital force is depressed by the influence of intoxicating substances. 

2. Many animals fall readily into this state of torpor, when the neces- 

* Ann. d. Sc. Nat.— Mai. Oct. Miiller's Archiv. 1836. Jahresbericht, p. cxix. 






sary degree of "external warmth which determines their geographical 
distribution is wanting ; it is from the necessity of a certain external 
temperature that birds migrate. 

3. The young of mammalia become torpid at a temperature which is 
sufficiently elevated for maintaining the vital force of the adult animals 
in an active state. This is proved by the observations of Legallois, on 
rabbits six or eight weeks old, which however may be restored from the 
torpid state by raising the temperature of the medium. 

Now, the cold in these cases does not exert a direct depressing 
effect on the respiratory process : all the first symptoms of the torpor 
from the influence of cold, namely, the insensibility, sleepiness, and 
debility, are rather indicative of depression of vital force from want of 
vital stimulus ; the subsequent effect on the respiration must therefore 
be regarded as a consequence, not as the cause of this torpor, just as in 

the case of syncope from nervous affections ; and the diminution of the 
temperature of the body is likewise a consequence of the depression of 
vital energy, which might perhaps prevent the generation of caloric sup- 
posed to take place in the lungs, by primarily causing retardation of the 
resniratory movements, and rendering the respiratory process less active. 
The facility with which this state of torpor is induced in some animals 
arises therefore from the greater delicacy of their structure, and from 
the vivifying and stimulating influence of warmth being more necessary 
for the continuance of their organic processes. This must also be re- 
garded as the cause of the winter sleep of hybernating animals, in 

which the only great peculiarity is, that in them the torpor may con- 

tinue a long time without danger to life. Of the causes of hyberna- 
tion advanced by Saissy and others, some are merely consequences of 
the depression of the vital energy ; others, such as the supposed large 
of the external nerves and small size of the cerebral vessels, do not 



The hybernation of animals then is perfectly analogous to what is called 
the nocturnal sleep of plants, — the change of position of their leaves, 
which is also occasioned by want of external stimulus, namely, the 
light; and is sometimes observed during the day, when plants are in 
the shade.* The ordinary sleep of animals, on the contrary, is by no 
means dependent on want of stimulus, but arises from the material 
change and exhaustion induced in the body by the state of action, and 
may, therefore, occur naturally at any time of the day, although from 
accidental causes it mostly comes on at night. 

The summer sleep of reptiles and of the tanrec seems, on the other hand, 
to arise from a disturbance of the system induced by too much heat. 
The want of water also appears to be a main cause of this state, which 



* Joum. de Phys. 52. 124, 


* 91 

m al tissues has a disorganising effect. 

raay therefore be regarded as the effect of the want of one vital stimulus, 
and of the excess of another. * 

These facts relative to winter and summer sleep, are closely connected 
Wl «i the known depressing effects of a long-continued high temperature 
°n the functions of the nervous system in man, and this is a very fit 
occasion for comparing the effects of heat and cold. Both may induce 
a disturbance of the excitability of the body, as well as irritation, inflam- 
mation, and sphacelus. The sudden violent action of cold on warm ani- 

Very cold bodies, when touched, 
produce a sensation of pain and then numbness. When the cold is 
m ore extreme, sphacelus or local death ensues. A slighter application 
°t cold, by extracting the animal heat, produces symptoms of inflamma- 
tl on and irritation, from the effort which is made by nature to restore the 
balance in the part. A moderate degree of cold has at first an exciting 
effect. Thus cold water produces instantaneous reddening of the skin, 
a ^ I have myself observed when bathing in the month of October ; but 
this effect is only momentary, and the phenomena of disturbance of the 
internal organs from extraction of heat soon follow. Cold is sometimes 
used in this way, as a stimulant, to produce a temporary disturbance of 
the nervous system, which may be beneficial. In fevers with a hot dry 
skin, cold water often acts indirectly as a vivifying stimulant, and 
restores the action of the skin, as warmth does in parts suffering from 
cold. The secondary effects of continued cold are always relaxation of 
the nervous system. The gradual action of cold to a high degree in- 
duces in the human subject a state of torpor, and in hybernating animals 
the state of hybernation by the withdrawal of a stimulus ; while a too 
elevated temperature also depresses gradually the action of the nervous 
system, but probably by producing a change of composition ; and in the 
sandy deserts excessive heat with want of water, causes asphyxia, and 
gives rise to the summer sleep of reptiles and the tanrec in hot climates. 


Of the developement of L 


the light visible in the waves, especially in the track of sailing vessels, 
which has been observed as far south as 60° S. L. arises from the presence 
of luminous animals in the water. These animals are in part infusoria, in 
part polypifera,— veretillum, pennatula,— in which it is chiefly the polypes 
themselves which are luminous; while many medusae also, perhaps all 
those of tropical climates, and some annelides — nereides and polynoe 
tulgurans,f — planariae, and mollusca— - particularly pholades, salpae, and 

* See also Pastr6, Nov. Act. Acad. Nat. Cur. 14. 661. 

1* For an account of the Polynoe fulgurans, an annelid e which contributes to the 

phosphorescence of the Baltic, consult Ehrenberg in Poggendorf s Annal. d. Phvsik 
1831,9. ' 














pyrosomata, — contribute to the phosphorescence of the sea. It appears,, 
that even the water which flows from these animals is also luminous, 
and that the phosphorescence continues for a certain time after death. 
When pholades are placed in a vacuum, the light disappears, but be- 
comes again visible on the re-admission of air. When dried, they re- 
cover their luminous property in some degree on being rubbed or 
moistened. Meyen* distinguishes three sources of phosphorescence in 
the sea: 1. mucus dissolved in the sea-water; 2. animals covered 
with a luminous mucus, — medusee, pholades; 3, animals possessing 




In the carci- 

phosphorescent organs, 

nium opalinum, or oniscus fulgens, special organs for the develope- 

ment of the light are seated in the fourth and fifth rings of the body. 


[Ehrenberg t 

covered that in many medusse of the Baltic light issues solely from 
particular parts of the body : in some, as the cydippe pileus and Oceania 
pileata, from the spot where the two ovaries are situated ; in others, as 
the Oceania hemispherica, from the base of the cirrhi, or from organs 
near the cirrhi, and alternating with them at the border of the animal. 
The dead animals were not luminous in the slightest degree. M. 
Ehrenberg believes the developement of light to be connected with the 

sexual function.] 

The luminous insects are the elater noctilucus, phosphoreus, and igni- 
tus ; the pausus sphserocerus, scarabseus phosphoreus,, several species of 
lampyris, and the scolopendra electrica.J In the elater, the principal 
sources of the light are two oval spots at the side of the thorax covered 
with transparent laminae. Treviranus could discover no difference be- 
tween the luminous substance and the fat of the body. In the glow- 
worms, — lampyris noctiluca and splendidula, — the light issues from 
the under surface of the last three abdominal rings^ particularly from 
two whitish spots on the last ring ; the ova of the lampyris splendidula 
are also luminous, and it seems that the pupa and larva are not entirely 
without light. In these animals the internal parts of generation, ac- 
cording to Treviranus, are the source of the light. The apparently volun- 
tary influence which the animal exerts over the emission of light, is 
effected, Treviranus says, by the inspiration of air. All observers ex- 
cept Macartney and Murray agree that in irrespirable gases, and in a 
vacuum, the phosphorescence ceases, or at least diminishes. After the 


death of the animal, the phosphorescent property is not entirely extin- 
guished. The luminous parts, even after being dried, recover their 
brilliancy when moistened with water. The brilliancy of the luminous 
beetles does not diminish for several hours when they are placed in 
water, but ceases immediately in oil ; it is restored, however, when the 

* Nov. Act. Nat. Cur. vol. xvi. suppl. 
t Abh. d. K. Academie d. Wissensch. zu Berlin, p. 411. % Trevianus, Biol. 5. 97- 



msect, whether dead or living, is exposed to the vapour of fuming 

citric acid.* From all the above facts, the 

opinion of Treviranus 

appears most probable, namely, that the light is derived from a matter 
containing phosphorus, which is formed under the influence of light, 

u > once formed, is in some measure independent of light. Several 
P ^enomena would lead us to believe, that the luminous insects absorb 

gut during the day, like the Bononian stones, and emit it in the evening ; 

llJ s was indeed the opinion of Carradori, Beccaria, and Monti, and is 
Su pported more especially by the circumstance that this absorption of 

J ght is evidenced by several mineral substances such as sulphate of 
D &rytes mixed with sulphuret of barium, oystershell heated to redness 
Wl th sulphur, &c. and also by several organic substances, when dried, 
su ch as seeds, flour, starch, acacia gum, quills, cheese, yolk of egg, muscle, 
tendon, isinglass, glue, and horn. But this opinion does not agree with 
the observation of Todd and Murray, namely, that glow-worms shine 
ln the evening, even when they have been kept in the dark during the 


Macaire and Macartney, however, deny that this is the case.f 


There is no instance known 

°i the developement of light in any of the higher animals, except, per- 
haps, the phosphorescence of the ova of lizards, and that which has 
been sometimes observed in the urine. [Some fishes have been recently 
discovered to be luminous.^] The supposed luminous property of the 
eyes of many mammalia, particularly of the predacious animals, and more 
especially cats, and also of the eyes of oxen and horses, is now scarcely 
regarded but as one of the superstitions of medicine. The luminous 
appearance of the eyes of some animals arises from the reflection of the 
light from a brilliant tapetum which is devoid of black pigment ; for which 

reason the eye of the white rabbit is especially brilliant, and the eyes of 
the Albino Sachs are said to have been luminous. Prevost§ was the first 
to explain the phenomenon ; he showed that it could never be seen in com- 
plete darkness, and is dependent neither on the will, nor on the passions, 
but is the effect of the reflection of light which enters the eye from with- 
out. Independently of Prevost, Gruithuisen || had observed the same 
facts. Rudolphi«|j was of the same opinion, and remarks that the appear- 
ance of light can be seen only in certain positions, and is also perceptible 
m the eyes of dead cats, when regarded in a favourable direction**. The 
Albinos are themselves never sensible of the light which is visible 

On this subject, consult Treviranus, Biologie, loc. cit. Tiedemann's Physiol, i. 
488—510. The translation, p. 257—271. Gmelin's Chemie, 81—86. 


+ Tiedemann's Physiol, i. 503. 

t Paper by Mr. Bennet, read at the Zoological Society, May 30th 1837. 

§ Biblioth. Britannique, 1810, t. xlv. 

II Beitrage zur Physiognosie und Eautognosie, p. 199 

1f Physiol, i. 197. 


I have myself made the same remarks. See my treatise " Zur vergleichende 

p hysiologie des Gesichtsinnes ;" Leipz. 1826, p. 49. 






I am glad to find 

ns. He ob- 

to others in their eyes.* Esseiyf moreover, has shown that the eyes of 
cats, dogs, rabbits, sheep and horses, are not luminous when external 
light is perfectly excluded; and that the reflection of light remained the 
same when the cornea, iris, and lens were removed. 
Tiedemann'sJ experience correspondent to these obs< 
served the luminous appearance of the eyes of a cat, in a head which 
had been twenty hours separated from the body. It is then the more 
astonishing to find the emission of light from the eyes of many American 
animals more than once asserted in so distinguished a worJ^as Rengger's 
Natural History of the Mammalia of Paraguay, and to find it there said, 
that this emission of light ceased on division of the optic nerves. But 
even this testimony cannot induce me to alter my conviction. 

Some persons have imagined that the sensation of light produced 
by pressing the eye was also owing to the emission of light. But it is a 
mere sensation like that of pain in the skin, and is produced by any irri- 
tation of the retina, from whatever cause, whether from chemical, 

electric stimuli, or from an internal organic cause. 

mechanical, or 

The flashes of light perceived when the retina is thus irritated are un- 
attended with any emission of light, and are, therefore, never visible to 
any other person than the subject of them, 

* See Schlegel, Beitrag zur nahern Kenntniss der Albinos ; Meiningen, 1824, 


f Esser, Kastner's Archiv. viii. 394. 

J Tiedemann, loc. cit. 

§ Compare my remarks on a medico-legal case, in which a person was said to have 
recognised a robber by the light produced by a blow on the eye. Mailer's Archiv. fiir 
Anat. und Physiol. 1834, p. 140. 

Note on the temperature of Insects .—I have been favoured by my friend, Mr. New- 
port, with the following interesting facts relative to the developement of heat in in- 
sects ; they are extracted from a paper presented to the Royal Society on the 15th of 

June, and not yet published. 

The amount of heat developed is proportionate to the quantity of the respiration ; 
being, caeteris paribus, greater when the changes produced on the air by respiration are 
greater, and vice versa. Berthold detected the evolution of heat only when several 
insects were collected together, not in one isolated from the rest. This must 
have arisen from his having ascertained the temperature only while the insect 
was in a state of rest ; for Mr. Newport found that, although during such a state the 
temperature of the insect was very nearly or exactly that of the surrounding medium, 
yet, when the insect was excited or disturbed, or in a state of great activity from any 
cause, the thermometer rose, in some instances, even to 20° Fahr. above the tempera- 
ture of the atmosphere,— for instance, to 91° when the heat of the air was 71°. ^ The 
increase of heat is not dependent simply on the rate or velocity of the circulation as 
measured by the pulsations of the dorsal vessel ; for in the earlier stage of the larva the 
amount of heat developed is less, while the frequency of the pulsations is greater ; and at 
a later stage of the larva condition the frequency of the pulsations is less, and the heat 
greater, while at the same time the quantity of respiration, on which the evolution of 

heat really depends, is also increased. 

Mr Newport has observed, that a short time previous to each change, the tempera, 
ture of the insect, as well as the frequency of the pulsations, and quantity of respira- 
tion, suffer a diminution. 




Of the Circulating Fluids, their Motion, and the Vascular System. 



^ i he quantity of the blood in the body cannot be exactly determined : 
is calculated, however, that in adult individuals it varies from eight to 
thirty pounds. It is the fluid from which are derived the materials for 
the formation and nutrition of all parts of the animal body. It takes up 
the effete materials from the different tissues for the purpose of their 
excretion by special organs, and is renovated by the new nutrient 
batters poured into it by the lymphatic vessels. These nutrient matters 
consist partly of substances introduced from without, and partly of matters 
which have already been organised components of the body. Their con- 
version into blood is effected not so much, probably, by the operation of 
particular organs as by the general action of all parts of the system upon 
them ; for in the ovum, even before most of the organs exist, and when 

the first traces only of the central parts of the nervous system are 
formed, blood is generated within the area vasculosa by the germinal 
membrane, which is the cicatricula or germ more fully developed by 
the attraction and assimilation of the fluids of the ovum. 

The blood which is brought to the heart from the lungs by the pulmo- 
nary veins, and projected by the left ventricle through the aorta and its 
branches into all parts of the body, has a bright red colour; that which 
returns through the venous system of the body to the right ventricle, 
and is thrown by it again into the lungs, has a dark red colour. The 
blood is also red in some invertebrate animals, as in the red-blooded 


* On the blood generally, consult Parmentier and Deyeux in ReiPs. Archiv. b. i. 
heft. 2, p. 76. Hewson's Experimental Inquiries, 1772, in German, Vom Blute. 
Nurnb. 1780. Prevost and Dumas, Bibliotheque Universeile, t. xvii.p. 294. Meckel's 
Archiv. viii. Scudamore on the Blood, London, 1824, or iiber das Blut aus d. Engl. 

burg, 1826. Berzelius, Thiercbemie, 1831, or the 7th volume of his Traite de 
Chimie, translated, into French by M. Esslinger. Denis, Rech. Experim. sur le Sang 

in, Paris, 1830. Thackray, Inquiry into the Nature of the Blood, London 
1819. Dr. G. Burrows, Croonian Lectures for 1834, in Medical Gazette. 







» i 
i ■ 




It has a reddish colour in some of the mollusca, at least in the 
planorbis, according to the observation of Treviranus and myself. In 
many invertebrate animals it is colourless. 

If the blood is examined with the microscope either in the minute 
vessels of a transparent part, or immediately after it has flowed from the 
body, it is seen to consist of small red particles or globules, and a clear 
colourless fluid. This fluid is the lympha or liquor sanguinis, and must 
not be confounded with the serum, which is the thin fluid that separates 
from the crassamentum during coagulation. The liquor sanguinis can 
be obtained free from the red globules before coagulation takes place, by 
filtering the blood of the frog or some other animal in which the red glo- 
bules are so large as not to pass through the white filter paper. m 
red particles are specifically heavier than the fluid, and consequently 


can contain no gasiform substance. 


The specific gravity of human blood varies from 1-0527 to 1-057. 
has a saltish taste, a weak alkaline reaction, and a peculiar odour,— ha- 
litus sanguinis, — which differs somewhat in different animals, and is 

strongest in the blood of the male sex. 

The blood of all vertebrate animals usually coagulates within the 
period of from two to ten minutes after its escape from the vessel ; the 
blood of the human subject requires from three to seven minutes for its 
coagulation, that of the rabbit two minutes only. It becomes first a ge- 
latinous mass, which slowly contracts, and presses out a dirty yellow 
fluid,— the serum,— which appears first in drops on the surface, and 
gradually increases in quantity. The red coagulum is called crassamen- 
tum, placenta, coagulum sanguinis, or clot. 

The serum has a specific gravity of from 1-027 to 1-029. It has a saltish 
taste, and in the higher animals has a weak alkaline reaction, which is 
scarcely perceptible in the frog. Herman was led into the error of 
supposing the serum to be acid, by observing that blood treated with 
tincture of litmus yields a reddish serum, which, however, arises from 
the red colouring matter of the globules being soluble in the tincture, 
iust as it is in water. The serum holds in solution several animal matters, 
of which the chief is albumen. This substance requires for its coagula- 
tion the action of certain chemical agents, such as acids and alcohol, or 
a temperature of 158° Fahr.; it does not coagulate spontaneously. 

If the red coagulum is washed for some time in water, the colouring 
matter is dissolved, and a white fibrous substance remains which is called 
fibrin. This substance, like the red clot, sinks in water unless it acci- 
dentally contains bubbles of air. 

In females during pregnancy and in the puerperal state, in acute rheu- 
matism and in inflammation,— indeed in all cases where the blood coagu- 
lates more slowly than usual, 
surface of the fluid before coagulation takes place, and the consequence 

the red globules often subside below the 



the cl 

ere to the rod with which it is stirred, 
e rest of the blood remains fluid with the red globules floating 

J that afterwards, when the whole mass coagulates, the upper part of 
e lol 1S WhUe '- formin S the inflammatory crust or buffy coat,-while 

globi ' Pan " "f' Wh£n fresh bl °° d is stirred q uic %' the red 
into col J? n °i lncIuded in the coagulum; the fibrin coagulates slowly 
whiJe ° t 1 i ourJes s fibres, which adhere to the rod wir.h whinh it L afi«~i 

ttiav'in^ eSh bl °° d ' If ex P° sed t0 a vei 7 low temperature, freezes, and 
when it I ***** ^ preServed ' bein S sti11 susceptible of coagulation 
a thous 1 \ t u aWed * Alkalies P^vent the coagulation of the blood ; even 

sulphat f ^^ ° f ° aUStiC S ° da haS this effect * Some salts also ' as 
Potash G h S ° da - nitrate ° f P otash > carbonate of soda, and carbonate of 

this h n mixed with the blood out of the body, prevent or retard 

of th* en ° menon * Fontana states that the poison of the viper, and that 
hav e ^ 1CUna ' added in the proportion of one part to twenty parts of blood, 

latio f Same effeCt ' While the vi P er ' s P oison quickly induces the coagu- 
are° n ° -^ bl °° d when inserted into a wound of the living body. There 
vessT^ 111 Circumstances ' also > in which the blood remains fluid in the 
sh S k S> ! mmdy ' in men and anima l s k iHed by lightning or strong electric 
an ° d C . S ' m those Poisoned by prussic acid, in animals hunted to death, 

that - n ^ en kIlled bj violent b l° ws on the epigastrum; and it is said 
at m these cases the limbs do not become rigid. 

the rT 1 UndCr the circumstances stafc ed, blood, when removed from 
wl G h ' alWayS coa S u l ate s 5 whether it be kept at rest or in motion, 
w lether it be placed in a temperature equal to that of the living body, in 
vacuo, m close vessels quite filled so as to exclude the air, or in various 
gases which do not form part of the atmosphere. [Dr. B. Babington* 
has shown that coagulation is retarded by exclusion of air, and to such a 

degree, that the red particles have time to subside. By letting blood 
flow mto a vessel containing oil, he obtained a thick fibrinous covering, 
while a portion of the same blood received into an empty vessel formed 
no buffy coat.] The sole cause, therefore, of the coagulation is, that the 
Proper combination of its elements is maintained so long only as the 
t *ood is under the influence of living surfaces, viz. of the vessels. [This 
jequires explanation. Blood which is enclosed in a vessel between two 
'gatures, or of which the motion in the vessels has been impeded in 
an y way, coagulates, though more slowly than out of the body ; it seems 
necessary, therefore, not only that the blood should be in contact with 
ivmg surfaces, but also that it should continue in motion.] Blood extra- 
cted in the body, also, generally coagulates. 

°lk'sf experiments seem to show that coagulation takes place with 
extraordinary rapidity after the brain and spinal marrow have been 

Medico-Chirurgical Transact, vol. 
t Comment, de Sanguinis Coagulatione. Groeningen, 1820. Diss, sist S 
oa gulantis Historiam. Groning. 1820. 

Schroeder van der 












A \\ 



broken down ; in a few minutes even after the operation, coagula were 
found in the great vessels. Mayer observed that, after the application 
of a ligature to the nervus vagus, the blood coagulated in the vessels, 
and death was thus produced. In four experiments, however, which 
were performed under my direction, two on dogs and two on rabbits, 
although the animals were examined immediately after death, which was 
the effect of this operation, — ligature of the nervus vagus,— in two 
cases only was a small coagulum of the size of a pea discovered in the 
left side of the heart, none in the pulmonary vessels. Hewson, Par- 
mentier, and Deyeux, have observed that blood extracted from the 
vessels coagulates more rapidly in proportion as the vital powers of the 

animals decline. 

Several observers— Gordon, Thomson, 


for example,— declare that they have observed elevation of temperature 
during coagulation ; while Dr. J. Davy* and Schroeder v. d. Kolk deny 
this most decidedly. 




Of the Red Particles . % 

There is great want of accordance in the descriptions which writers 
have hitherto given of the red particles of the blood,§ I shall state 
here merely the results of my own observations. || 

Mode of examining the red particles.— F "or the purpose of microscopic 
examination, the blood must not be diluted with water, for this fluid has 
the property of immediately changing the red particles from a flattened 
to a spherical form, and of rendering circular those which were elliptical. 
The blood should be either diffused very thinly over the surface of the 
glass, or diluted with some serum, or with a weak solution of common 
salt or sugar ; these solutions produce no change in the appearance of the 


* Tentamen experimental de Sanguine. Edinb. 1814. Meckel's Archiv. i. p. 117- 
See also Meckel's Archiv. ii. 317, and iii. 454 and 456. 

+ From original researches. See Poggendorf's Annal. 1832. 8. 

+ [Considerable alteration has been made in the arrangement of the matter con- 
tained in this account of the red particles, for the sake of greater perspicuity.] 
' § A full account of the observations of different physiologists will be found in E. H. 
Weber's edition of Hildebrandt's Anatomie, Bd. i. and in Burdach's Physiologie, 
Bd. iv. The best observers have been Muys, Fontana,— Nouvi Osservazioni sopra 
i globetti rossi del sangue, Lucca, 1766. Hewson,-Experimental Inquiries, pt. iii. 
Lond. 1777. Prevost and Dumas,-Biblioth. Univers. t. xvii. Meckel's Archiv. t. vm. 
R Wagner,— Zur vergleichende Physiologie des Blutes, 1834. 

\\ [Professor Miiller is evidently not aware that the most important facts stated in 
the following description of the red particles of the blood were ascertained long ago in 
this country, although they have since been much neglected. The translator has 
deemed it advisable to add a brief sketch of the labours of previous physiologists in the 
investigation of this subject.— See p. 107. 

re <l particles. 



Woocfof t h e fr0 ^s t T " eXamining :the8e b0dieS in the 

^is ani mal on f h S l° Place f Sma » *«»■% * the serum of the blood of 

It ^ doubt Ls anrfbuTh, a ^ t0 * & Sma11 ««•** ° f th « blood - 
Wood havinTh" r V ** USe ° f bad 'laments, and to the 

^^^Z^lrl^ *" ** *"***»» given of 



so various. 

elliptical or n,V, i I, ery vanous ; Dut > whether they be 

P"cal 01 circular, they are always flattened. 

disk,* ^T™ 1 "' "^ i g thC hUman SUbjeCt ^ they are -cular 
well as in t "T ^ " the C&lf ' Cat > do S> and rabbit, as 

anbai s a w ?' and a "! winced that they are flattened in all these 

to ascertl f "" ? ' ^^ ^ fisheS ' Xt WOuld be interesting 

renMl f ° rm m the ora ithorhynchus and echidna. In birds 

are 2' ^^ *** ^^ they are elli P tic '+ In som e fishes they 
^d Mrd! TJ f ^"^ T* P 6 ^ so 4 In reptiles, amphibia, 

the prono'rt 7 f ' dmmeter ° f the red P articIes are ab ™t in 

c proportion of two to one. 

bodl r ,T ireS a g ?° d microsc °P e t0 P ercei ve the flattened form of these 

* ag ta ed Tn7 ^ " ^ *" ***** ^ ° f a — iferous animal 
and w X T ^ the r CroSC ° Pe > many ° f the red Prides roll over ; 
line thl P . °" " r edgC arS SeeD t0 resemble a short thick dark 

Thev 1 e f remitieS ° f Which are not rounded, but cut off abruptly. § 

portfon !o t, G T Pa ^ d t0 ' Pi6Ce ° f m ° ney S6en ed ^ ways « but > in Pro- 
LneT T r l0ng diarnete u r '. ^ey are much thicker than a piece of 

fift f' ,W an bl °° d thdr thickneSS IS ab0ut one-fourth or one- 

nrth of their transverse diameter. 

The flattening is greatest in reptiles, amphibia, and fishes , and of all 
animals is most remarkable in the salamander. In birds, also, the red 

a P mpntbil are " **'**** ' ^ "" * S ° *** a *°^° as t 

In the frog, the red particles-the thickness of which does not mea- 
sure more than one-eighth to one-tenth of their long diameter-present 
when seen edgeways, a slight prominence rising from the centre of each 
lateral surface, as Prevost and Dumas have represented. In other ani 
jnals, even in the salamander, I have observed no prominence of this 

both R :, Wagn r; b0Wever > has observed it in many other animals, 
ooth reptiles and fishes. H 

* See Plate i. %. 1. 

f See Plate i. figs. 2, 3, 4, 5, and 6. 

tRudolphi describes the red particles of fishes to be circular, and I formerly thought 
they W ere so in the clupea alosa ; hut it was before I was acquainted with the right 
method of examining them. The error arose probably from inaccurate observation 
oi from diluting the blood with water. * 

§ Plate i. fig. 1 . 

II Plate i. figs. 2, 3, 4, 5, and 6. 

ii 2 



s * 


: : . 




Central spot.— In the centre of each red particle is a spot, which in 
the circular bodies is circular, in the elliptic also elliptic ; on the illu- 
minated side of the particle it appears light, on the opposite side dark. 
This spot has sometimes — I may say, indeed, has always in the elliptic 
globules, — the appearance of being produced by a central nucleus, 
especially when the particle is brightly illuminated, and all shadow 
avoided. By a less brilliant light this central spot suggests rather the 
idea of an elevation ; and this is particularly the case in the frog, 
has not at all this appearance in the salamander, nor in birds, nor fishes. 
The apparent elevation in the red particles of the frog's blood is most 
marked when the quantity of serum in which they are contained is 
small, and then it looks as if it were surrounded by a depression between 
it and the outer ring.* These, I say, are the appearances presented 
under certain circumstances : I give no opinion as to their mode of pro- 
duction. But as the red particles in birds, salamanders, and fishes, 
generally present no appearance of an elevation on their flat surfaces 
when they are rolling over on their edge under the microscope, it is 
evident that in them this central spot cannot be produced by an eleva- 
tion, and must be referable to the central nucleus, which all these 
bodies contain. And the slight lateral prominence observed in the par- 
ticles of frog's blood, and, by Wagner, in those of many other animals, 
when seen edgeways, must also be attributed to the central nucleus. 

In the red particles of mammalia, the central spot never appears 
elevated. It is from writers having assumed that what they observed 
in one animal existed also in others, that so much confusion with refer- 
ence to this subject has been produced. In many points, however, I 
have found the observations of Prevost and Dumas correct. In mam- 
malia, the red particles have sometimes, by a certain light, the appear- 
ance of being very slightly excavated from the border towards the cen- 

Dr. Young is inclined to regard this appearance as a real depres- 
sion of the surface : this, however, seems to me to be very improbable ; 
for I have satisfactorily ascertained that each of these bodies contains a 
small nucleus, equal in thickness to the red particle itself. When the 
red particle of mammalia is placed obliquely, so that part of one surface 
and part of one border meet the eye, the upper border forms a dark 
semicircle, convex in one direction, and concave in the other. I will 
presently detail experiments by which I am able to demonstrate the 
existence of a nucleus, with chemical characters perfectly different from 
those of the outer vesicle, in each of the red particles of the frog and 
salamander. And as this nucleus has under the microscope exactly 
the same appearance in the red particles of birds and fishes as in those 
of amphibia, it would be expected to exist in those of mammalia also. 


* See Plate i. figs. 2 and 3. 

-j- See Plate i. fig. I. 



And although, on account of the minuteness of these bodies in mam- 
m aha, it is more difficult to demonstrate the nucleus in them, I have 
with an excellent (Fraunhofer) microscope really seen it, and distinctly, 
ven m the red particles of human blood, I have seen a minute, round, 
accurately-defined nucleus, which had a more yellowish and shining 
aspect than the transparent part around it. The existence of the nuc- 

eus can also be demonstrated by the action of acetic acid, though much 
Jess distinctly than in the case of frog's blood. 

Ihe size of the red particles in human blood is pretty uniform ; some 

ew are larger, but none have twice the diameter of the majority. In 
e frog also their size is for the most part equal ; some, however,, with- 
out differing in any other respect, are somewhat smaller than the rest, 
and a Ppear to be, as it were, in the process of formation. Prevost and 
-Dumas have found the red globules in the embryo to be larger than 

hose of the adult animal. In the embryo of the rabbit their dimensions 

are very unequal ; the greater number are quite as large as in the adult, 

and a few are more than twice that size. In the tadpole the same bodies 

appear to be somewhat smaller than in the frog, and are much paler. 

Ihe red particles of amphibia are the largest that I am acquainted 
with ; in 


birds, reptiles, and fishes, they are smaller ; in mammalia 
smallest, and among mammalia those of the goat are the most minute, 
as Prevost and Dumas correctly observed. In the calf they are rather 
smaller than in man. The red particles of frog's blood being taken as 
a standard of comparison, and observed under the microscope side 
by side with those of other animals, it is found that those of birds 
are about one-half the size of those of the frog; that the red particles 
of the salamander are somewhat larger, not so much as one-third larger 

than those of the frog, they are rather more elongated ; those of the 
lizard compared with the same bodies are found to be about two-thirds 
the size, while the circular particles of human blood measure only 
one-fourth the long diameter of the elliptic particles of frog's blood. 
The red particles in man I have found to measure from 0-00023 to 
0-00035 of an inch French in diameter. 

[From the following table it will appear that the measurements of the 
red particles given by different physiologists, with the exception of Sir 
E. Home and Mr. Bauer, are all within or nearly within the limits 
assigned by the author. 

Dr. Young 

Captain Kater 

Dr. Wollaston . 

Sir E. Home and Mr. Bauer 

Prevost and Dumas 

Dr. Hodgkin and Mr. Lister 

Professor E. H. Weber 

Parts of an English inch 









I' J 



, It 



Professor R. Wagner 
M. Milne Edwards 
Professor M'tiller 

Parts of an English inch 







t0 stiwr 

The following table, showing the size of the red particles in the blood 
of different vertebrate animals, is derived from Professor Wagner's 
treatise, a few examples only of each class having been selected.] 

Name of the animal. 

Name of observer. 

In mammalia, 
Simia callitrix 

Prevost and Dumas 


Prevost and Dumas 

In birds. 
Common fowl 


Goose, Raven, House- 
sparrow, and Goldfinch. 


Prevost and Dumas 


Size infractions of an 
English inch. 




• • 









422 6 





2 7 6~S 


20 3 8 

3~8 lO 



38 lO 

In reptiles. 
Land tortoise 

Do. . 
Coluber berus 
Laeerta agilis 

Prevost and Dumas 

Prevost and Dumas 
Wagn er 






TUT? 8 


234 o 







In amphibice. 
Salamandra cincta et 

cristata . 
Rana bufo, esculanta, 

Rana esculanta 

In fishes. 
Lophius piscatorius 
Squalus squatina 

Prevost and Dumas 



R. Wagner 
Do, . 

88 y 


1 1«J3 

TToT cu TJiTt" 

1 U38 

1 107 

to w 



l 9 O 3» 


C%/e globules in the blood. — In the blood of the frog as obtained from 
the heart of the animal, I have found other smaller bodies, much less 
numerous than the red particles, about one-fourth their size, and per- 
fectly spherical. They agree in every respect with the scanty globules 
seen in the lymph of the frog, which will be described in a future 
section ; and are evidently identical with them, being poured into the 
blood with the lymph and chyle. 

[Hewson* observed these lymph globules in the blood, and believed 
that they were identical with the nuclei of the red particles. He 

* Hewson's Experimental Inquiry, p. 133. 




supposed that the nuclei are formed in the lymphatic glands, and that 
the red envelope is afterwards found around them, chiefly by the spleen.] 
It is possible that the nuclei of the elliptic particles are derived from 
these lymph globules. The nuclei freed from the covering of colouring 
matter are of about the same size, but they are elliptic in form, and 
*& the salamander distinctly flattened, while the lymph globules are 
spherical. In mammalia, too, the globules of the lymph and chyle are 
much larger than the nuclei of the red particles in the same animals; 
and from the entire red particles they differ, in being perfectly insoluble 
in water, while the red particle, with the exception of its minute nucleus, 

is soluble in that fluid. 

It is generally believed that the conversion of the chyle into blood is 
effected very quickly. Such may certainly be the case ; but the diffi- 
culty of distinguishing the chylous globules in the blood is sufficiently 
explained by their being diffused among the more numerous red par- 
ticles. During the ordinary coagulation of the blood of man or mam- 
malia generally, the chylous globules are included in the crassamentum 
with the much more numerous red particles, and the serum is left trans- 


parent ; but if coagulation is retarded by the addition of a minute pro- 
portion of carbonate of potash, the red particles subside, while the 
chylous globules being lighter are suspended in the upper part of the 
fluid, rendering it milky. 

Different action of serum and water on the colouring envelope. — Sir 
Everard Home* speaks of the red particles undergoing rapid decomposi- 
tion ; this is quite incorrect. The blood of a mammiferous animal from 
which the fibrin has been removed by brisk stirring, retains all the 
appearance of fresh blood, and the red particles remain suspended 
in it, with no change of their form or size discoverable by the best 
microscope after the lapse of several hours, or even on the following day. 
At the end of twenty-four hours, although they have then subsided 
several lines below the surface of the fluid, no perceptible solution of 
their red envelope has taken place ; the supernatant serum is still yellow, 
and untinged by the red colouring matter. In the blood of sheep and 
oxen, thus deprived of fibrin, the red particles subside 1| line in the 
course of from twelve to twenty-four hours, and after being kept several 
days at a temperature of 59° Fahr. the depth of the supernatant fluid left 
free from red particles by their subsidence is not more than 2^ lines, and 
the fluid is but very slightly tinged. In human blood, and in that of the 
cat, the red particles subside somewhat more rapidly, namely, as much 
as four or six lines in a few hours. In the serum of frog's blood, they 
subside very rapidly, but nevertheless, they preserve their form and size 
unaltered for several days, if the atmosphere is not very warm. 

But if water be added to such a mixture of the red particles and 

* Philos. Trans. 1818. 










serum of the blood of a mammiferous animal, a part of the colouring 
matter is quickly dissolved,, and a large portion of the red particles sink 
to the bottom of the vessel. The further effects of water on the red 
particles are best observed in a mixture of the serum and red particles 
of frog s blood. Such a mixture I obtain by removing each portion of 
coagulum as it forms, having first agitated it a little in the serum to 
separate any adherent particles. By this means a considerable number 


of the red particles are left in the serum, although many are removed 
in the coagulum. Thus prepared, the blood of the frog is adapted for 
many microscopic experiments on the changes produced in the red 


particles by different substances ; experiments for which fresh blood 
cannot be used on account of the coagula which form in it. 


-If such blood is mixed with water, the colouring matter of 
the red particles is dissolved. To accelerate the solution, the water 
should be added in considerable quantity. The solubility of the colour- 
ing matter in water enables us to demonstrate the existence of a nucleus 
in each of the red particles. For this purpose a watch-glass should 
be filled with a mixture of this blood and water, and after waiting a 
short time for the particles to subside, the whole should be 
ed in a large glass vessel partly filled with water, taking care not to 
disturb the sediment in the watch-glass. 

or twenty-four hours the red deposit will have become white, and, if 
some of it be examined with a microscope, the elliptic red particles will 
no longer be seen, but in their place a great number of small bodies, not 
more than a fourth the size of the original red particles, and for the most 
part roundish in form, a few only oval. If the sediment is examined 
at intervals during the period mentioned, it will be quite apparent 
that, in proportion as the water becomes tinged with the colouring 
matter, the elliptic particles lose their red envelope, and become smaller 
and smaller until the colourless nuclei merely remain. These nuclei are 
not further soluble in water, but form at length a mucous matter at the 
bottom of the glass, still consisting of the same granules. The nuclei 
of the red particles cannot be demonstrated in this manner in human 
blood on account of their minuteness ; but from analogy it is probable 
that, when human blood is treated as above, the nuclei of its red par- 
ticles also remain undissolved, but are suspended in the water. When 
the blood of mammalia coagulates, the red particles are included in the 
clot ; and when the red colouring matter is extracted by washing in 
water, the nuclei may still remain in the fibrinous mass, or they may be 
separated from it, becoming suspended in the water, but they are not 

After standing for eighteen 

Effects of difft 

The nature of the 

red particles of the blood is much elucidated by the changes produced in 
them by the action of various fluids. To watch these changes a ^ood 



de^Z r rOS T ^ reqUir6d ' ^ the bl ° 0d ° f the fr °S - «*"w 
fibrin Id I mP T ' A dr ° P ° f the fr °^' S blood fre * d *°™ the 
should b^LfrLl Eny . J flUid ° f Whi ? h We de8ire » * *e effect, 


ex periments 


made t n ' u i_ ^ F S^ss, ana tne two drops 

mixed L ' ^ CffeCtS Pr ° duced at the raoment that th ey become 
^ay be rf W&tched > means of the microscope ; or the red particles 
added T • eXa T ed se P a '-ately, and again after the re-agent has been 

• itns is the method I have constantly adopted in the following 


remark M ^ instantaneous effect of w ater on the red particles is very 
chan * Th ° Se ° f human blood become indistinct ; the further 

counf eS f that - ^^ SUffer Cann0t be distin S uished wit h accuracy, on ac- 
Slobul ? eIr minUte SiZe ; * thin1 ^ however ' that they are rendered 
could ^ ' While they Wel ' e fl ° ating ab0Ut under the microscope, I 
everv P r' CeiVe n ° ne With a Sharp border * But m the blood of the frog 
globnl ang V S distinct 'y «een. The elliptic bodies immediately become 

in th. fl ^ 2ff presentin S a shar P e %e to the eye as they roll over 

detent \ f^ * ey "* CnIarged at the same tim *> I ca ™ot 

shorts \ I diame ter is now intermediate between the long and 

uneoutr " ^ ell, ' PSiS Which ^ bef ° re P resented Many appear 
maioritl TlT ^^ ° U tbe SUrface ' and ^"regular form; the 
A-ZITa g ° bular ' but n0t accurat ely m. In several the nucleus is 

wan inf' " "!! Dg6r at thC C6ntre ' bUt Et the Side ; in a few h is wh <% 
by the^riT Jt S T: " ^ f- e Vi ° lent Change P roduced ia them 

l k i ! ° aUSed the ex P ulsion of tbe nucleus, for, besides these 

globules winch have lost their nuclei, a few nuclei without'en^e Z 

also be seen strewed over the field of the microscope. These free 
nuclei are ^tmgu.shed from the smaller globular or chylous particle, of 

be n ! !Z ft T^ d6SCribed ' hy their elH P tic fo ™ M«e water 
being add d th d partideg ^ ^.^ ^ 

ca bon 7 , DOth T g bUt the inS ° lubIe nuclei reraai - Water to which 

sowT / P ° ta ' C ° mm0n "^ S31 ammonia ^ or sugar has been dis- 
olved produces no change in the size and form of the globules, unless 
t be a saturated solution of carbonate of potash, which seems to pro- 

a «ce a slight and gradual diminution of their size. 

Dortf ' *i Bei * ZeliUS remark8 ' di8S0lves the Colou ™g ma tter in all pro- 
ful d -uT° St ^f DUmaS h3d denied this ' but the experiments 
vond 7 C l : ^T y those P erf °rmed with frog's blood, prove, be- 
yond doubt, that the colouring matter is really dissolved, and not sua- 
penoed in minute particles in the water. 

. Berzelius seems to attribute the insolubility of the colouring matter 

in serum to the albumen, which this fluid contains. But I cannot think 

iat this is the sole cause, and believe this property of the serum to be 

c ^efly owing to the salts which enter into its composition; for when 



— ■ 




Ii i 



I added to a small quantity of the frog's blood under the microscope a 
solution of yolk of egg, the change in the red particles from the flattened 
to the spherical form, took place as rapidly as when I added pure water ; 
but when, in place of the solution of yolk of egg, I added a watery solu- 
tion of any salt which produces no chemical change in the blood, such 
as carbonate of potash, or common salt, the form and size of the red 
particles were not in the slightest degree altered. 

Acetic acid. — If, instead of water, dilute or concentrated acetic acid 
is used, the elliptic particles immediately become irregular in form, and 
some are rendered globular. The red colouring matter is in a few 
minutes almost entirely dissolved, leaving small bodies not more than 
one-third or one-fourth the diameter of the original red particles. These 
are not globules contracted by the action of the acid, but nuclei deprived 
of the red colouring matter. The colouring envelope is not however 
wholly dissolved, for with the Fraunhofer microscope I could still distin- 
guish a delicate exceedingly pale line, surrounding the central nucleus. 
The outline of these bodies is the same as that of the red particles; in 
those obtained from frog's blood I could not distinguish any flattening, 
but those from the salamander's blood are as distinctly flattened as the red 
particles themselves. The length of the nuclei from frog's blood is the 
double of their breadth ; some few, however, approach the circular form. 
In the red particles of the salamander, the nuclei are more elongated, 
their lateral borders are almost parallel, while their extremities are 
rounded. By means of acetic acid, the extremely minute nuclei of the 
red particles of the blood of mammalia can be rendered visible, but the 
most careful manipulation and a very clear instrument are required for 

the experiment. 

If the blood of the frog freed from fibrin be mixed in some quantity 
with acetic acid, the same change in the globules takes place ; but we 
also observe that the nuclei subside in the form of a light brown powder, 
which after the lapse of several days, remains undissolved, and which 
is found even at a later period, if examined by the microscope, to consist 
of the unaltered nuclei of the red particles. Fibrin and albumen are not 
rendered brown by the action of acetic acid ; on the contrary, it renders 
them transparent, and by degrees in part dissolves them. The brown 
colour of the deposit, therefore, seems to depend on some of the colour- 
ing matter which still adheres to the nuclei, and is perhaps chemically 
changed ; for the nuclei obtained by subjecting the red particles to the 
action of a large quantity of water are white, and remain so when acetic 
acid is poured over them. The acid used in these experiments was 
ascertained to be pure, and was somewhat more concentrated than the 
acetic acid of the Prussian pharmacopoeia. 

Muriatic acid does not dissolve all the colouring envelope ; it dimi- 
nishes the size of the red particles very slightly. Chlorine destroys the 





^ 0U mnf : e I r : S ^!rl b !. C °" eS firSt bTO ™> *<"* -% "toe, 


albumen at the same time coagulates into globular 
11 this white matter is examined by the aid of a microscope, 

the form nf th ir - , CAdUJ,xieu °y tne am of a microscope, 

in it Z I P ^^ GS ° f the bl ° 0d Can Sti11 be distinguished 

two wa 1 % are r m6What Sma " er ' The ex P eri ™nt may be made in 
internal^ ' ^ ^ may be paSSed throu S h a tube moistened 

row ne^ J lth *? bl °° d ' ° r the b,ood »V * poured into a very nar- 
rows a 1 f g SS J f fiIled With Chl ° rine - In the latter case the blood 
^ short way down the side of the jar, but soon coagulates. 

acid. 6 ° rm ° f the red P articles is not affect ed by oxygen or carbonic 

J • 

mor potasses dissolves the red particles very quickly,— the nuclei 

e as the colouring envelope, 
01 m - The solution is effected still more rapidly by liquor "ammonite, 

without previously changing their 

an( j • . ~~ "*-" " w « c layiuiy uy nquor ammonia, 

becom/i°i C ? mplete; bU * ^ the m ° ment ° f mixture the red P^cles 
and th g k i AlC ° h ° l mCrely P roduces s1i ght contraction of them ; 
cloud ri TT^f albumen ' Produced by the coagulation of the serum, 

nine »Ta \ ^^ *** r6nder thc red P articles distinct. Strych- 
me and morphia produce no change in them. 

^! h tV nd ^ ° fthe red P artides are the same in arterial and 

us Wood. This is contrary to the statement of the otherwise accurate 

*al enbrunner, who describes them as increasing somewhat in size, and 

pal a t 't" 6 " b ° r t' Which " disS ° lved awa * as it were, in their 
passage through the capillaries. I also found that no change was pro- 
duced in the form of the red particles of the frog, when I tied the Ws 
at their root and cut them out ; the animal still lived thirty hours 
probably from respiration being carried on by the skin, as it was in the 
fishes m Humboldt's and Provencal's experiments 

^l^rlTX:! ^ red Tl Cle: r^ 6XiStenCe ° f the red * articl - in ^ blood 
vas discovered by Malpighi, and shortly afterwards by Leeuwenhoeck * in 1673 who 

these bo„fr «\ ' •"* *' ^ **"" The re P^ntation that he has given of 
It in th m „" intereSti " g ' InaSmUCh aS H PP0VeS that he had obs <*ved the oval 

ss^zr f s b j t observations ° f M - de ia T ° rre ' f which - 

next ? glV6n 5 ^ ^ PartideS ° f the bl °° d ^ Mr - H ™>* *» 1 77 Z 

flaulf ^ attentl ° n * ThlS ^ ° bSerVer asce ^-^ with certainty, that they are 

thlth ^ T f f qUadrUPedS ' " WeH " ^ the ° ther ™ tebrate *«? "* ^ found 

oft f I" *TT T " eqUa% dIStinCt " ^ livin * animal ( { o* instan <*> *» the web 
c rres'2 8 ^ whe " ™ ed f ™ ** body. He observed that their size does not 

Zul t t Tt ^ 1 ? a r a1 ' bUt " Sma " er in qUadr "P eds than in birds, and 

fowl t? u ,?' ^ * " y aPe ^^ ^ the ? 0lm 8 of the -P^ and common 

owl than in the adult animals. Hewson knew the advantage of diluting blood with 

His experiments to prove that the central spot is produced by a solid nucleus 

e particularly interesting, since they show that he was fully aware of the changes 

Produced on red particles by the action of water. He describes their change from a 

attened to a. spherical form, when water was added ; the gradual thinning of the 


Phil. Transact, 1674 and 1684. 

t Phil. Trans. 1765. 

t Loc. cit 

. ; 

: ' 





external vesicle till merely the middle globular and very small particle was left, 
nucleus, he observes, is less easily soluble in water than the envelope. The property 
which serum possesses of not dissolving the red particles or altering their shape, 
Hewson attributed chiefly to its saline ingredients, and proved by experiment that so- 
lutions of neutral salts, if not too concentrated, have the same property as serum in this 
respect, and are equally well adapted for diluting the blood in microscopic experiments. 
He observed that concentrated solutions of salts produce contraction and shrivelling of 
the vesicles. Other of Hewson's observations have not been confirmed. 

Dr. Young* published, in 1818, a concise account of his microscopic examination of 
the red particles. He confirmed Hewson's remarks as to the existence of a nucleus in 
the particles of the blood of the skate, but believed that in those of human blood there 
is no nucleus ; on the contrary, that their form is that of a doubly concave lens ; 
although he remarks that the apparent central depression on each surface may depend 
on some internal variation of refractile density. 

The appearance of a central depression had been previously seen by Fontana,t for 
in all the figures which he gives of these particles, the line which surrounds the central 
bright spot is darkest on that side which is most illuminated. But he paid no atten- 
tion to this circumstance. 

The statements contained in the memoirs of Sir E. Hornet and Mr. Bauer, on this 
subject, were nearly all erroneous. These observers added nothing to our knowledge 
of the bodies, but unfortunately were too willingly credited, and caused the more ac- 
curate observations of Hewson to be neglected. 

The subsequent researches of MM. Prevost and Dumas § tended in part to confirm 
the views of Hewson, namely, as to the flatness of the particles and their consisting 
of a nucleus and enveloping coloured vesicle. They first perceived a slight promi- 
nence in the centre of the lateral surface. But in some respects their statements more 
nearly coincide with those of Sir E. Home and Mr. Bauer, and here they are obviously 

Thus they suppose that during coagulation the red particles lose their co- 
louring envelope, and that the nuclei then coalesce. They believe that the red vesicle 
falls to pieces when acted on by water, without being dissolved ; and they even give a 
drawing of a red particle of the blood of the salamander, which had been some days 
in water, and of which the envelope had burst and the nucleus not escaped. The 
immense magnifying power with which this was viewed, namely, 1000 diameters, 
would excite a doubt as to the accuracy of the observation, and this doubt is strength- 
ened when we consider that all the best observers agree as to the solubility of the 
external coloured portion of the particles in water. 

By varying the mode of observation, Dr. Hodgkin and Mr. Lister || endeavoured 
to prove the correctness of Dr. Young's opinion that the red particles of human blood 

of a doubly concave lens. They think that this is demonstrated, 
1. by the circumstance that the image of any opaque body placed between them and 
the light, is transmitted in an inverted position, precisely as would be done by a con- 
cave lens ; 2. by the appearance presented by the particles when viewed dry as 
opaque objects ; and 3. by the appearance of two concave surfaces when the particle is 

in error. 


at right angles to the surface of the glass in the focus of the lens. 
The originality of Professor Muller's investigation of these bodies consists principally 
in his employing blood from which the fibrin had been removed ; and in his ascer- 
taining the action of different substances, particularly the gases, upon them. The pro- 
perty of serum and saline solutions was known to Hewson, who also knew well the 

* Medical Literature. t Traite du venin de la Vipere. t Phil. Transact. 1818. 

§ Loc. citat. 

|| In their translation of Dr. Edwards, on the influence of physical agents on Life, 

Appendix, p. 432. 





effect of the admixture of water; while Dr. Milne Edwards had, in 1826,* observed 
* at acetic acid strips the red particles of their envelopes and leaves the nuclei isolated. 

Professor Wagner's f account of the red particles in the vertebrate classes are 
c iefly confirmatory of the observations of preceding physiologists ; but he extended his 
servations to a greater number of species. He observed the central elevation in birds, 
reptiles, and fishes : in reptiles he found this elevation generally less prominent than 
lr * birds : in all the vertebrate classes the border is generally cut off abruptly, but in 
SOme nsn es it appeared to be sharp, the central prominence rising gradually from it. 

Wagner has also examined these bodies in the different classes of the invertebrata. 
He found that whatever the colour of the blood might be, the particles floating in it were 



e c * rcu Jation, these particles underwent great changes of form. In some invertebrate 
animals a number of small granules or nuclei are seen in the interior of the blood par- 
ticles. In the blood of some animals the particles are very scanty ; Wagner formerly 
supposed that they were entirely wanting in some species, and instanced the hirudo 
vulgaris ; but he has since found them in this animal. They are most numerous in 
tne blood of cephalopods and ascidi<e, but even in them they are less abundant than in 
the vertebrate animals. The following table is sufficient to show that the size of these 
bodies varies very much in the different invertebrate animals as well as among the 


Name of animal. 

Maja squinado 


Larva of ephemera 


Octopus moschatus 
Helix pomatia 

Astirias aurantiaca 

Observer . 


Prevost & Dumas 

Of the liquor sanguinis. 

Greatest diameter. 
Infractions of an English inch 



Wtt tO 


S3 23 










t0 t^t] 

The liquor sanguinis^ — the fluid portion of the blood in which the 

red particles float during life, — separates, when coagulation takes place 

previously in 

into two parts, 


solution. The fibrin coagulating encloses within it the red particles. 
The serum still retains the albumen in solution. We shall treat first 

the Jib 

Of the Jib 

It is generally supposed, that the coagulation of the blood results 
from the aggregation of the red particles. These bodies are thought 
to be merely globules of fibrin in an envelope of red colouring matter, 
and it is imagined that the clot is formed of these red particles, and 
is rendered white by washing, from the red envelopes being removed 
from the particles so as to leave merely the nuclei of fibrin. This 
explanation of the process of coagulation was proposed more especially 
by Sir Everard Home and by Prevost and Dumas. It has been pre- 
supposed also by Dutrochet in his late investigations on the action 


* Ann. des Sciences Nat. t. ix. 

-f Loc. citat. 

$ See the representation of the corpuscules in the blood of the scorpion, Plate i 





r I 






I I 



of galvanism on the blood. Berzelius, observing that lymph contains 
fibrin in solution, conjectured that the blood also must contain it in 
that state ; because, he says, the lymph is a fluid separated from the 
blood: a still stronger reason might be adduced, — namely, that the 
lymph is poured into the blood. Berzelius, therefore, suggested that 
the clot was formed by the fibrin coagulating and enclosing the red 
particles. This idea of the fibrin being in the state of solution in 
the blood has been advanced several different times. I have been so 


fortunate as to discover a definitive proof of Berzelius's conjecture.* 

In some frogs blood which had been received into a watch-glass, 
I observed that before the whole mass coagulated, some colourless 
transparent clots formed, which I could draw to the edge of the glass 
with a needle; and on pouring off the blood, one or two minutes after 
it had flowed from the animal, I perceived that there were points 
or small fragments of similar coagula remaining adherent to the bottom 
of the glass. To this experiment it might be objected that in am- 
putating the frog's thigh, which is the readiest mode of obtaining 
blood from this animal, some lymph had escaped with the blood, and 
had given rise to these coagula; I therefore collected the blood for 
the future directly from the great ischiadic artery, which runs among 
the muscles at the posterior part of the thigh. I laid bare this artery, 
which is easily found, on account of its running close to the great ischi- 
adic, or crural nerve, as it is usually called, and collected the blood from 
the artery only, and with such care as to be sure that I had pure 

* [In England this has not merely been the opinion of individuals, but, before 
physiologists were led astray by the incorrect observations of Sir Everard Home 
and Prevost and Dumas, it was the opinion generally held and taught in the schools. 
Thus Mr. Hewson, speaking of the constitution of the blood, does not assert it as 
his own discovery ; he says, " It is well known that the crassamentum consists of 
two parts, of which one gives it solidity., and is by some called the fibrinous part of 
the blood, or the gluten ; but by others more properly termed the coagulable lymph ; 
and of another which gives the red colour to the blood, and is called the red globules." 
Dr. Gordon also, in his Syllabus of Lectures on Anatomy, describes the blood to 
consist of the fluid portion and of the red portion, and the fluid portion to consist 
of the serum and lympha ; and I am informed by Dr. Sharpey that Dr. Gordon 
was in the habit of giving this description of the blood in his lectures, not as the 
result of a new discovery, but as the general opinion of physiologists. 

As to the proofs on which this opinion rested, much more had certainly been done 
than Professor Muller supposed. Hewson, who was acquainted with the effects of 
neutral salts in retarding the coagulation of the blood, observed, (p. 11, Experimental 
Inquiry,) that when a salt, such as Glauber's salts, is mixed in considerable quantity 
with the blood, the red particles subside, and the surface of the mixture becomes clear 
and colourless, and that this clear fluid can be poured off from the red part, and 
is found to contain coagulable lymph, which coagulates on the addition of water. 
He observed (p. 35), that " in inflammation the surface (of the blood) became trans- 
parent, that the transparency went deeper and deeper, the blood still remaining fluid :" 
he removed a part of the clear liquor with a wet tea-spoon, and put it into a phial 



high magnifying 

blood. I obtained blood in the same way from the heart, which is 
done with more facility. In this blood, of the purity of which there 
could be no doubt, the same small transparent coagula were always 
formed before the entire mass of blood coagulated. A drop of this pure 
blood was diluted with serum, and placed under the microscope. The 
globules then appeared widely separated, but in the spaces between 
them I could discern the formation of a coagulum which connected 
these bodies together, however wide the intervals between them ; and 
y placing a needle between any two globules, and moving it about, 
could set the whole mass in motion. As the red particles of the 
tr °gs blood appear very large when viewed by a 

power, this experiment admits of the greatest accuracy, and is perfectly 

A here is, however, another much easier, and indeed still more un- 
questionable method of demonstrating the same fact. Knowing that 
the red particles of frogs blood are four times the size of those bodies 
In the blood of mammalia, I conjectured, that, although the red parti- 
cles of the latter animals pass through filter paper, those of the frog 
flight not : I found this opinion correct. Thus, as generally happens, 
the most simple means was the last thought of. I am now enabled to 
show at lecture by an easy experiment, that fibrin is held in solution in 
the blood ; that it passes limpid through the filter, and then coagulates. 
The experiment can be made quite on a small scale with the blood of a 

with an equal quantity of water, a second portion he kept in the tea-spoon ; " both these 
portions, as well as the surface of the larger mass of blood, coagulated ; the portion in 
the tea-spoon, when compressed, yielded serum." He observed also that inflamma- 
tory blood coagulates more slowly than healthy blood (p. 49) : u May we not con- 
clude, therefore/' he says, " that in those cases where the inflammatory crust appears 
the coagulable lymph of the blood is thinner, and its disposition to coagulate lessened ? 
both of which circumstances contribute to the subsidence of the red globules from 
the surface of the blood, which then coagulates." And again : " This remarkable 
appearance might be accounted for by supposing that the lymph had ascended to 
the surface of the blood in those cases \ but this is improbable from considering that 
m its coagulated state it is of greater specific gravity than the serum and sinks in 
it ?" These passages show that Hewson had no doubt in his mind as to the state 
in which the fibrin exists in the blood. But still his proofs are defective in one 
point ; he did not show that the red globules still preserved their perfect state 
when the fibrin separated, and that the fibrinous transparent portion of the blood 
did not contain colourless globules ; that the fibrin consequently was independent 
of the red particles. In this respect the merit of the definitive proof is certainly 
due to Professor Mtiller. Mr. Hewson knew that the crassamentum contained red 
particles in their perfect state, for it was by agitating crassamentum in the serum 
that he obtained the red particles for observation, but this did not prove that all 
were unchanged. Professor Miiller, by his experiment of filtering the blood before 
coagulation, has proved that the fibrinous portion contains no globules, and has shown 
that, when the fibrin is removed, the red particles can still be seen by the microscope 
all in their perfect state.] 








single frog; a small glass funnel and a filter of common white filter 
paper, or not very thick printing paper, are all the apparatus required. 
The filter must of course be previously moistened ; and it is better to 
add some water to the blood as soon as the latter is poured into the 
filter. What then passes through is a perfectly clear serous fluid 
diluted with water, and merely tinged in the slightest degree by the 
red colouring matter, which in frog's blood is not rapidly "dissolved. 
Sometimes it is quite colourless. If, in place of pure water, a very 
dilute syrup — containing one part of sugar in two hundred or more parts 
of water — is employed, the red envelope of the particles is not at all acted 
on, and the filtered fluid is perfectly colourless. No globules can be 
discerned in this fluid by the aid of the microscope. In a few minutes 
a coagulum forms, which on account of its transparency would not be 
remarked, were it not drawn out of the fluid with a needle. This 
coagulum gradually contracts, becomes whitish and fibrous, and then 
has exactly the aspect of human lymph.* The fibrin of the blood is by 
this means obtained in a purer state than is possible by any other 
method. Of course all the fibrin of the blood is not obtained by this 
process ; the greater part of it coagulates before it can pass through the 
filter. To find the paper best adapted for the filter, some trials must 
be made with different kinds. If the paper is too thin, some few 
red particles pass through it with the fluid, and will afterwards be 
seen here and there in the coagulum. If the paper be of the proper 
thickness, the coagulum will not contain a single red particle. There 
is no distinct appearance of granules in the fibrin thus obtained ; it 
is quite homogeneous ; when it has contracted and become white, it 
acquires a finely granulated aspect. This appearance, which it pre- 
sents when viewed with the compound microscope, may, however, arise 
merely from unevenness of the surface. 

There is still another mode of proving that fibrin exists dissolved 
in the blood of the frog as well as of mammalia. By adding to the 
blood of man or any vertebrate animal some drops of a very con- 
centrated solution of carbonate of potash, coagulation is retarded, so 
that the red particles have time to subside. In the space of half 
an hour a soft coagulum forms, of which the lower part containing 
the red particles is red, while the upper part is white. 



and Dumas for an attempt to calculate the amount of the red particles 
in the blood of different animals from the weight of the crassamentum 
when dried. However, as Berzelius has remarked, the result of such 
calculations can never be exact, because the crassamentum contains 
a large quantity of serum, the albumen and salts of which must be 
left behind during desiccation; and if the coagulum were washed, 

* See Book i. Section iii. on the Lymph. 



^ove d ly if" ?,?' bUt ^ ^ C ° l0UrIn S matter rf~ would be re- 
s ider the IZ ' ♦ T"*\ ' remembered ^ that Prevost and Dumas con- 
^ they i " ^ l h ° Uy deHved fr0m the red P-ticles, so that 
the sum of rt °J ^ , am ° Unt ° f red Partides ' must be re S ard * d as 
t^ir „ umer ^ e red P r deS ^ fibriU t0gether ' With this —tion, 
component. / f ° nS ° f thC P r °P° rt ional weight of the different 

c °mponent parts of the blood 

a] so to thp^ • T ue ' inese remarks a PP'y 

the quan ri! ? 6 r Se , eXCe l6nt researches of Lecan « with regard to 
quantity of the red particles in the different temperaments and 


To det 


™a in d^"* the ^^ ° f fibn ' n in the bl °° d ° f different animals 
mode f ent dls eases, ne w experiments are required. The best 

with ascert aining the quantity of fibrin is briskly stirring the blood 

of a a 1 ° r bUn ° h ° f twigS ' When the fibrin se P ara tes in the form 
itsnaf°T leSS ° r nearlj colourless coagulum, and leaves the blood of 
chan J COl ,° U j r '' the red partideS fl ° atin S in h havin S undergone no 
method I , that Water had not been added '* This ™ the only 
state f Y I the r6d Partides Can be se P arat ^ in their perfect 

linen 21 A ^ ^ the fluid parts are strained off through a 
the weth/ Tk S ° lid fibHn WaShed S ° aS t0 purif ^ h from ser ™ > 
«^£^ZT^ in a ~*? ^-^7 of blood can be 
be zmJ-T- 6XaCt P r °P° r tion of red particles cannot 

ascertamed. The weight of fibrin deducted from the weight of 

same quantity of 

kill in- 

assamentum ascertained to be formed from the same qu 
ooq, say one hundred parts, will leave a remainder, which win , n 
oicate the quantity^ of red particles, together with the albumen and 
salts contained ,n the coagulum. The proportion which the albumen 

° the red P artic] es may be ascertained by finding the weight 

of albumen: in a certain proportion of serum; and then, after , c „ luV ing 
the fibrin from some blood of the same animal, evaporating the blood 

Wood B wh eli ri (T r It6 ^ CMmie ' t0m - ViL CMmie Animale ) remark * ^at when 
Pound ^ ^"^ ° f hS fibrin iU this ™* is ex ™* «^er a com! 

cZiZrr 6 ' th : re ?rf s are no ionger visiwe; but in ^ ^ 3* 

mm inuted f ntSj whlch he regardg ag port . om of the peii . cie ^ ^ 

he IT; rr n , T ing , in a yelI ° WiSh ^^ They paSS thr0U ^ h the filt «- Paper, 
« says . but so d0 the red panicles of the fregh unst . rred blood of the h J?v> 

er Z ehu S further states that when blood is kept several days in a temperature of 

quite T *Z * §mentS SWy SUbsIde and leave the -npenuitanf fluid 

ZJr-'TT^T™^ fluid " Peddened ^ a ^le of the colouring 
patter being dissolved Notwithstanding the high respect I entertain for this greaf 

wan, I must say that the red particles of blood which has been deprived of its fibrin 
y stirring, always appear to me to preserve their perfect form unless water had 
°me into contact with them. I have examined these bodies in the blood of the 

° af , ox, cat, and man, previously freed from its fibrin in this way, and have never 

ound them altered in any respect, their flattened form being as distinct as in the 
fresh blood. 






K \ 






; ■ 



to dryness, and observing the weight of the water lost. Now admitting 
that this water, and consequently the water with which the red parti- 
cles were impregnated, contained the same proportion of albumen as 
the serum, the weight of the albumen left in the residue after 
the desiccation of the blood freed from the fibrin may be easily calcu- 
lated ; and, by deducting its weight from that of the whole residue after 
desiccation, the quantity of the red particles will be found. This is the 
method Lecanu appears to have adopted in determining the proportion 
of the cruorin, but it rests on a mere supposition. 

The only point which I have investigated, is the proportion of fibrin 
in the blood, this being the only one which can be determined with ac- 
curacy. From 3627 grains of bullock's blood I obtained, by stirring, 18 
grains of fibrin. The crassamentum of 3945 grains of the same blood 
weighed, when dried, 641 grains. So that in 100 parts of the blood of 
this animal there were 16*248 parts of dry crassamentum and 0*496 
parts of fibrin. Fourcroy estimates the quantity of dry fibrin in 1000 
parts of blood at from 1*5 to 4*3. Berzelius calculated that it was 0*75; 
while Lassaigne found it to be 1*2. In twenty- two experiments Lecanu 
found, that the proportion of dry fibrin in 1000 parts of human blood 
varies from 1-360 to 7-235 parts.* 

Proportion of fibrin and red particles in arterial and venous blood. 
Prevost and Dumas state, as the result of their experiments, that arte- 
rial blood contains more red particles than venous blood ; meaning of 
course that it contains more crassamentum. Arterial blood would be 
expected to contain more fibrin, because the material for the nutrition 
of the body is derived from arterial blood, and the lymph and chyle, 
both of which contain fibrin in solution, are being constantly poured into 
the central parts of the circulating system. The result of several expe- 
riments instituted by Mayer and Berthold, was the same. I thought it 
necessary, however, to assure myself of the fact. I therefore extracted 
1392 grains of blood from the jugular vein of a goat, and shortly after- 
wards 3004 grains from the carotid. The two kinds of blood were 
stirred separately so as to remove the fibrin, care being taken that none 
was lost. The arterial blood yielded 14| grains, the venous 5 \ grains of 
fibrin. So that in 100 parts of arterial blood there was 0*483, in the 
same quantity of venous blood 0*395 of fibrin. Denis gives the pro- 
portion of fibrin in arterial and venous blood as 25 to 24. Berthold 


found the proportion in the goat to be as 429 to 366, in the cat as 521 
to 474, in the sheep as 566 to 475, and in the dog as 666 to 500.f The 
mean result of the foregoing experiments is that the quantities of the 
fibrin in arterial and venous blood are in the proportion of 29 to 24. 

The substance which has been subjected to chemical analysis under 
the name of fibrin of the blood, is the matter which, while the blood is 


* Lecanu, Transact. Med. 6 Oct. 1831. 92. f Burdach's Physiologie, iv. 282. 



* P cu eT till l Wh r ° btained ^ Stirri ^ the bl ^> it is pure ; but 

of the ,! d y g e coagulum ' k ma y also contain 

the nuclei 

e red ttai.f;~i rni * tuluaili "*e nuclei 

cannot h„te v " h 'T^ Which theSe bodies «"» ia * 

»eigh beZen A ^ ^ I°" thm is scarcely any difference in 

-as! in? a ^ !L fih C ° agU , ^T ***** ° f i,S C ° Iouri "S ma «« ** 
•&*»* r" :, £? ? bta, " ed fr ° m the sarae «»»*y <* Wood by 

minute are rl P ° 8 !; I "' "" " UC ' ei ""* in man ™ alia a "> » very 

«>e *Z 77 J e C0, ° Uring matter ' and reraai0 8 "^"<Ied in 

«>c W or of ^ 7 * T e th<! C, °' ° f the bl0 ° d ' wne ' h » "f 
des oaf h mammaba ' ln the se ™»> » '^ge number of the red parti- 

in the L,? se P a ™« ed '" « heir PerfeCt State fr0m tl,e c ° a g«'«™. and float 

And if the nuclei are really contained in the solution of 

e serum. 

dL^T^?" 6 *' obtained by washing the crassamentum, -they wiH be 

lo Urin lit Ma . ^ty of blood under the microscope, the red co- 
can thlhP 7^ f S e ' '^ nCither the red P articles nor their ™clei 
it is oni k T Y S6en ; and *' in P lace of water > ace£ic a ^d * added, 
which r ; • c m °l t atte " tive ° bservation that ^ small central bodies 
Whl _ mam aftCr , thG S ° luti0n of the col °uring matter can be discerned. 



e nuclei which I obtained from frog's blood 

consist of 

Tin t». nnt • j-m , o "■*«"« vwiioisi, or 

affu]a not »" difficult to say ; they have the more general properties of 

coagulated fibrin and albumen.* 



In inflammation, and under some 

er circumstances, the blood coagulates in an unusual manner. Before 
coagulation commences, the particles subside to a certain extent leav 
wg the upper part of the still fluid blood colourless or milky • and the" 
upper layer of the gelatinous coagulum, which soon afterwards forms 
is white or of a greyish yellow colour, while the lower part is red' 
during the contraction of the coagulum, these two portions of the clot 
amrinish unequally in size ; the upper whitish or greyish yellow substance 

eon T 1 ^t * and ' alth ° Ugh at firSt the COa S ulum occu P- ; cd 

equally at a U heights the entire diameter of the vessel which contains it, 

e wmtish portion acquires at length a much smaller diameter than the 
ea portion, and thus arises the peculiar form of the coagulum of in- 
named blood. The cause of the unequal contraction of the two parts 
°r the crassamentum is, that in the lower portion the fibrin is kept 
mechanically extended, as it were, by the red particles which it con- 

tQlnCJ YYrl\iils\ ■!*-* 4-1-v ^ ,,^^^„ Aril _ ... . 

tains, while in the upper there 

none of these bodies to pre- 

sent its close contraction. It must, however, be understood that fibrin 

js present and coagulates in all parts of the clot. The formation of a 

"uffy coat may always be predicted before coagulation ; for the subsi- 

ence of the red particles being a necessary condition, the surface of 

* See page 120. 





the blood is observed to become first transparent,, and afterwards to 
acquire an opaline aspect. Mr, Hewson and Dr. B. Babmgton* have 
shown that the colourless fluid which produces this appearance can be 
removed with a spoon, and that it afterwards coagulates. This fact I 
have seen verified on the blood of a pregnant woman. [Dr. B. Babing- 
ton removed sufficient of the colourless liquor sanguinis to obtain a clot 
from which the serum separated. He has observed that in shallow ves- 
sels the buffy coat is less perceptible for two reasons : first, that the 
blood coagulates in them more quickly than in deeper vessels ; secondly, 
that the particles have less distance to subside. The form of the vessel 
also influences the size of the crassamentum, and therefore its propor- 
tion to the serum, which latter circumstance has been usually noted as 
important in disease. Thus the blood of the same person at the same 
bleeding, when drawn into a pear-shaped vessel, yielded a much smaller 
proportion of crassamentum than when drawn into a shallow basin ; in 
the former case the proportion of the serum to the clot being as 1000 to 
1292, in the latter as 1000 to 1717. In the former case, however, the 
clot is much more compact, the fibrin seeming to contract more firmly 
when its particles are less spread out and less distant from a common 


Cause of the buffy coat, — This peculiarity in the blood under certain 
circumstances, namely, the subsidence of the red particles to a certain 
extent before coagulation, might be supposed to depend on diminished 
specific gravity of the serum ; but. for as much as is known, the serum 
of inflammatory blood has the same specific gravity as that of healthy 
blood. The fact that inflammatory blood coagulates more slowly than 
blood under ordinary circumstances, may in some measure explain the 
phenomenon, for it may be imagined that the red particles would thus 
have sufficient time to subside before the fibrin coagulates. This was 
the view that Hewson took of the formation of the buffy coat. To as- 
certain the correctness of this mode of explaining the phenomenon, I 


instituted a series of experiments with different kinds of blood. First, I 
wished to ascertain the time in which the red particles begin to sub- 
side in blood from which the fibrin had been removed. As I have 
mentioned already, this subsidence of the red particles in the serum 
takes place much more rapidly in the blood of cats and man than in 
that of sheep and oxen; in the former instances it amounts to one line 
in an hour and a half, and in several hours to from four to six lines. 
But this is not sufficient to explain the formation of the inflammatory 
crust ; for although the coagulation of inflammatory blood takes place 
slowly, it does not occupy several hours, and, nevertheless, the buffy coat 
is frequently half an inch in thickness. I observed, in the next place, 
that the subsidence of the red particles is more rapid in blood of 

* Medico-chirurgical Transact, vol. xvi. p. 11. 

t Dr. Babington, loc. citat. 




winch the coagulation has been retarded by the addition of carbonate 
°* potash ; at least, in the case of the blood of man and that of the 


This effect is not produced in the blood of sheep and oxen. In 
a ^ the experiments in which the coagulation of healthy human blood 
™»° thus retarded, the red particles in five or six minutes sank one 
two and a half lines below the surface, and within an hour as much 
as four or five lines. The supernatant fluid became gradually milky, 
fnd, if too much carbonate of potash had not been added, coagulated 
ln to a soft viscous fibrinous matter. In one case in which the blood was 
not inflammatory, the fibrinous coagulum became pretty firm, and form- 
ed a kind of buffy crust. With the blood of the cat I obtained the 
same result. Thus, by merely retarding the coagulation, I was able 
give rise to the process by which the inflammatory crust is formed ; 
the only difference being, that the fibrin which formed the artificial 
crust was softer and more glutinous; which depended, perhaps, on some 
c ^emical change effected by the carbonate of potash. There is another 
ca use also for the greater firmness of the inflammatory crust ; it is, that 
mflammatory blood contains more fibrin than healthy blood,— a fact 
which Sir C. Scudamore ascertained. It is difficult to say why the red 
particles should begin to subside in healthy blood as soon as it is drawn 
rom the body, and yet sink so very slowly in blood deprived of its 
hbnn, even though it be inflammatory. The relative specific gravity of 
the serum and liquor sanguinis cannot be the cause, for the blood when 
deprived of its fibrin is specifically lighter than it was before. It may 
be that there is less adhesion exerted between the red particles and the 
hquor sanguinis, which still holds the fibrin in solution, than between the 
red particles and the serum without the fibrin. 

Dr. J. Davy has observed, that inflammatory blood, in some instances, 
does not coagulate more slowly than healthy blood, and since the pre- 
sence of fibrin in the blood appears from the above-mentioned experi- 
ments to favour the subsidence of the red particles, the formation of the 
buffy coat in these cases may arise from the blood containing a greater 
quantity of fibrin. So that the principal causes of the subsidence of the 
red particles and formation of the buffy coat in inflammatory blood 
appear to be the slow coagulation of the blood and the increased quan- 
tity of fibrin. The formation of a loose crust on the crassamentum in 
cases where we suspect a commencing disorganisation or decomposition 
of the blood, rather than that it contains an increased quantity of fibrin, 
is sufficiently explained by the slow coagulation of such blood. 

Of the Serum. 

The fluid which remains after the coagulation and contraction of the 
fibrin of the blood is called the serum, and, as we have before remarked 
must not be confounded with the liquor sanguinis. It is yellowish, has 







a saline taste, a specific gravity of 1-027 to 1-029, and, in the higher 
animals, has a distinct alkaline reaction. When exposed to a tempera- 
ture of 158° or 167° Fahr., it is converted into a gelatinous mass by the 
coagulation of the albumen which it contains, and this takes place 
in vacuo as well as in atmospheric air. The albumen is its most essen- 
tial component. Besides this, it contains a free alkali, 

bases. We 

soda, (potash, 

)— combined with albumen and salts of these 

O ' 

showing the proportional quantity of the solid components of the serum 
and the other ingredients of the blood in different animals. 

Name of Animal 

In 100 parts of Blood, 


Simia callitriche 
















Tor toi se 

In 100 parts of Serum. 






























84 60 


















89- 1 





From this table it appears, that in the serum of human blood about 

one-tenth part in weight consists of solid ingredients in solution the 
chief of which is albumen ; and that this relative proportion is pretty 
nearly maintained even as low as the fishes : while in these animals, 
the fishes,— and in the amphibia, the proportional quantity of the coa- 
gulum— fibrin and red particles— in the blood, is less than in the higher 

classes. The proportion of the solid parts of the crassamentum to those 
of the serum in human blood is as 12-92 to 8*69, or about 3 to 2. The 
blood of carnivorous animals yields more crassamentum than that of 
herbivorous animals. Dr. Davy states, that the blood of the lamb affords 
a softer and less abundant coagulum than the blood of the full-grown 
sheep. As Fourcroy has stated, the coagulum of foetal blood also is, 
according to my observation, softer than that of the blood of the adult 
animal. From Berthold's* experiments it appears that the quantity of 

* Beitrage zur Anat, Zool. u PhysioL Gott. 1831. 



to 805-26. 

fZ 5 I 1 *, ° f cold ' blooded ani ™ls is as great as in that of 

waim-blooded animals, while the colouring matter is less in quantity. 

^omposiUon of the blood in the different sexes, ages, and temperaments. 

i am inquiry, and with it a new epoch in this department of Physio- 

og'cal Chemistry, was originated by Lecanu. Lecanu* seems to have 

aoe an extraordinary number of observations, and to have compared 

inem with accuracy. He found the quantity of water in 1000 parts of 

blood to vary from 778-625 to 853-135, the average being 815-880 In 

!! e on7!f! e h VaHeS from 790 ' 394 t0 853 ' 135 » in the m ale, from 778-625 
/""" So that the blood of the female contains the greater pro- 
portion of water. This was the result also of Denis's experiments, of 
w ich twenty-four were made on men, and twenty-eight on women. 
ie latter author found the proportion of water in man to vary from 

tw ^ 782 ' ^ Woman frora 848 ta 75 °* The mean proportion of the 
wo is as 767 to 787. The quantity of water in the blood, according to 

ecanu, bears no determined relation to the period of life; Denis, how- 
ever, found its proportion greater in children and aged persons. With 
e spect to the temperaments, Lecanu found that, in the sanguine temper- 
ament, the blood contains less water than it does in the lymphatic. In 
women of sanguine temperament, the proportion of water in four expe- 
riments varied from 790-394 to 796-175 in 1000 parts of blood ; in 
women of phlegmatic temperament, it was found as the result of five 
experiments to vary from 790-840 to 827-130. The average in women 
ot sanguine temperament was therefore 793-007 ; in those of the phleg- 
matic 803-710. From similar observations on men, the average for 
those of the sanguine temperament of this sex was found to be 786-584- 

for those of the phlegmatic 800-566. Thus, in the female sex, the ex- 
cess of water in the phlegmatic temperament is 10-703; in the male it 
is 13-982. 

The proportional quantity of albumen varies in general from 57-890 to 
78270 ; the quantity of albumen is nearly equal in the two sexes ; it does 
not vary in any determinate degree between the ages of twenty and sixty, 
nor is there any striking difference in its quantity in the different tem- 

The quantity of crassamentum in 1000 parts of blood varies generally 
from 68-349 to 148-450, the average being 108-399. In men it varies 
from 115-850 to 148450, in women from 68-349 to 129-990; so that, 
according to Lecanu, the blood of men contains, in 1000 parts, about 
32-980 parts more of the components of the crassamentum than the 
blood of women. The quantity of the coagulum does not, however, 
appear to increase proportionally with the age, at least not between the 
ages of 20 and 60 years. The quantity of the coagulum is, however, greater 
lr * the sanguine than in the phlegmatic temperament, which agrees with 

* Beitrage zur Anat. Zool. u Physiol. Giitt. 1831. 




Denis's observation. In four observations on women of sanguine tern- 
peraments the proportion of coagulum in 1000 parts of blood varied from 
121-720 to 129-654; in five observations on women of phlegmatic tem- 
perament, from 92*670 to 129*990; the average in women of sanguine 
temperament being 126*174, in those of the phlegmatic 117-300, — the 
difference being 8*874. In men of the sanguine temperament the pro- 
portion of coagulum, in five observations, varied from 121*540 to 148*450 ; 
in those of the phlegmatic temperament, in two observations, it was 
1 15*150 and 1 17*484. During menstruation Lecanu found that the blood 

contained less coagulum. 



1 . Of the Red Particles . 

The nuclei. — No complete chemical analysis of the nuclei of the red 
particles has hitherto been made, on account of the difficulty of obtaining 
these bodies in sufficient quantity. The red particles being large in 
frog's blood, the nuclei can be easily obtained free from their envelope 
by the method already described. t They are insoluble in water, and in 
acetic acid they remain several days without suffering any change ; while 
they are soluble in a solution of alkali— of soda and potash, as well as of 
ammonia. In these characters they resemble coagulated fibrin and al- 
bumen, but the latter substances are more soluble in acetic acid. When 
the red particles of the frogs blood are treated with acetic acid, the 
nuclei are left in the form of a brown powder ; fibrin and albumen, on 
the contrary, are rendered transparent by the action of this acid. But 
the brown colour of the nuclei probably depends, as I have before re- 
marked, on their still retaining a portion of the colouring envelope, 
chemically changed by the acid ; for nuclei previously freed from their 

red envelope by the action of water do not acquire this colour when 
acetic acid is added. 

The colouring matter, hcematin y cruorin. — Berzelius has analysed 
cruorin in three states : 

1st. As it exists on the red particles ; 2nd. dissolved in water; 3rd. in 
the coagulated state, in which it is insoluble in water. 

1. The colouring matter in its natural state has a great affinity for 
oxygen, uniting with it, and becoming of a brighter colour whenever it 
comes into contact with it or atmospheric air. Carbonic acid is at the 
same time developed; this was the result of the experiments of Berthold, 
and of those of Christison and myself. If a stream of oxygen is passed 


through some blood from which the fibrin has been removed, this fluid 
becomes throughout of a bright red colour. The same change is effected 

* In this chapter Berzelius is chiefly followed 

t See page 104. 



on the surface of blood thus prepared, as well as of freshly drawn blood, 

i£Th T '°, Sir ' By ,0ng C ° nt8Ct with «»» *• Soaring 
matter becomes black, (which arises, perhaps, from the carbonic aci! 

aeam ^ * j „ , J «" 6 .ii. icu uujour cannot tnen be 

cW T \ Carb ° niC add ' sul P hurous a cid, ^d the acids generally, 
fibrnft \ C0 ° Ur ° f the bl0 ° d t0 a dark br0Wn ' Bl00d fr ^ which the 

become ^ en ^T^ abS ° rbS nitr ° US ° xide in lar S e *«*%> and 

tranl'l 1 PU1 * P ^ COl ° Ur; bUt itS " atUral Colour is stored by 
^ nsmittmg through it a stream of atmospheric air. Carburetted hy- 

Seve^l 1S i Smd t0 communicate a brighter colour to dark blood. 

r ai salts,— for example, common salt, nitre, and sulphate of soda,— 

^ a je the same effect.* Schroeder Van der Kolk observed that bright 

^ e spots were produced on the surface of venous blood by the electric 

obta^ ,° d0Uring matter is dissolved by water in all proportions. It is 
cannt m i he StatG ° f SOlUti ° n by wa shing the crassamentum ; but as we 
ed i? a * .7™°™* the nuclei at the same time, these bodies suspend- 
m tne fluid necessarily enter into its analysis. 

• The solution of the cruorin is reddened less strongly than blood by ex- 
P sure to air. By evaporating it at a temperature of 1 22° Fahr. a blackish 
a " 1S ; btained which can be rubbed to a dark red powder, and is then 
again soluble m water. At 158° Fahr. the colouring matter in the watery 
solution coagulates, and is then insoluble. Alcohol and the mineral acids 
also coagulate it ; and the addition of an alkali to its solution in acetic 
acid, or of an acid to its solution in an alkali, likewise precipitates it in a 
coagulated state. The precipitates thrown down by the salts of earths 
and metallic oxides are in part brown ; others are black, and others red t 

3. In the coagulated state produced by a heat of 158° Fahr the colour 
mg matter is red and granular ; when dried by heat, it becomes black. 
The long action of boiling water changes the red colouring matter, iust 
as it does fibrin. Acids also form with coagulated cruorin, as with 
Jbrm neutral combinations, which are soluble in pure water; those 
tormed with cruorin are of a dark brown -colour. The coagulated 
cruorin is soluble in alkalies also. It is precipitated from its solutions 
«» alkalies and acids by tannin. Tiedemann and Gmelin have discover- 
ed that it is slowly soluble in alcohol, giving this fluid a dark red colour 

may, therefore, be separated from the albumen which it contains by 
means of alcohol, in which the albumen is insoluble. Lecanu on this 
account, regarded the substance forming the pellicle of the red par- 
ticles,— the haematosine,-as a compound of the true colouring matter 
which he calls globulin, and albumen. There is, however, no reason for 
this supposition ; for the albumen may be derived from some serum, or 
from the nuclei of the red particles, separated with the colouring matter 

* Berzelius, loc. cit. p. 48 

t lb. pp. 50, 51. 




r r 




from the clot during its ablution.* Michaelis gives the following as 
the result of his analysis of this substance : 


In Arterial Blood. 
. 17-253 

. 51-382 
. 8-354 
. 23011 


In Venous Blood. 





From this it appears, that the elementary composition of the colouring 
matter agrees with that of fibrin : the former substance, however, leaves, 
when calcined, a larger quantity of ash ; which ash contains a large pro- 
portion of iron ; for Berzelius and Engelhardt have proved that Brande 
and Vauquelin were incorrect in asserting that the colouring matter does 
not contain a larger proportion of iron than the serum and other animal 
substances, Oehlenschlagerf also discovered iron in the blood of puppies 
which had not yet sucked. Iron is therefore not an accidental ingredient 
derived from the food. The ash of the colouring matter is always alka- 
line, and of a red-brown colour ; and, according to Berzelius, in human as 
well as in bullock's blood amounts to 1± or 1^ per cent of the weight of 
the dried colouring matter. In the colouring matter of calf's blood it 
amounts, according to Michaelis, to 22 per cent. Berzelius, in the 
analysis of 1*3 parts of ash, obtained from 100 parts of dried colour- 
ing matter, found 

Carb. soda, with traces of phosph. soda, . . . 

Phosphate of lime, 
Pure lime, » 

Subphosphate of iron, 

Oxide of iron, . 
Carbonic acid, and loss, 




In another experiment Berzelius obtained from 400 grains of dried 
colouring matter, five grains of ash, which was composed of 

Oxide of iron, 

Subphosphate of iron, ....... 

Phosphate of lime, with a small quantity of phosp. magnes. 

Pure lime, . * . * . 

Carbonic acid, and loss, . 





The average result of Berzelius's experiments is, that the colouring 
matter contains rather more than one-half per cent, of its weight of me- 
tallic iron. Few persons have hitherto found manganese in the blood. In 
two grammes X of blood ashes, Wurzer§ found 0108 of oxide of iron, and 

# 034 oxide of manganese. 

State in which iron exists in blood. — Menghini asserts that blood dried 

* Lecanu in Poggendorf 's Annal. 1832. iv. 550. 

t Kastner's Archiv. 1831, Sept. Oct. p. 317. 

± [A gramme equals 15-438 grains avoirdupois.] § Schweigger's Journ. lviii. p. 481. 

• - 



and powdered is affected by the magnet, by virtue of the iron which it 

nteins. while, according to Sir C. Scudamore, the red colouring matter, 

^ en calcined, is not so affected. None of the common and most deli- 

acid IZ \ S J° T ° Xlde ° f ir ° n '~ aS ferroc y an ate of potash, tannin, gallic 
or nfc v Str ° ngest mineral acids,-detect the slightest traces of iron 
apoel° SP .f G f lime b thG colourin S m atter before it is calcined ; it 
state f t 1 herefbre ' that the iron and lime of the blood are not in the 
solntJ e Th6 aSsertion of Fomcvoy, that the colouring matter is a 
iron r ♦ • Sub P hos P hate of the Peroxide of iron in albumen, and that the 
is pr , amed m the ch y le is neutral Phosphate of the protoxide of iron, 
ph °r hy the ex P eriments of Berzelius to be incorrect ; for the sub- 

wh° S h -° f the peroxide of iron is insolubl e in serum and in albumen, 

ether with or without the addition of an alkali. The opinion of MM. 

^revest and Dumas, that the colouring matter is albumen containing per- 

acid 6 ° f " ° n ^ solution ' a PP ears t0 be also incorrect ; for the mineral 
s and aqua regia should extract the iron from the uncalcined colour- 
g matter* if such were its constitution. 

the - ngelhart+ has made some important discoveries relative to the share 

tion'T h i aS ^ pr ° ducin S the red col ° ur - He first showed that a solu- 

hvdr °" nng matter in water > when impregnated with sulphuretted 

y rogen, after a time loses its colour, becoming first violet, then green. 

rim S T t XaCtlj the effeCt Which the Same gas has on iron 5 and the ex Pe- 
ment therefore seems to prove that this metal contributes to the pro- 

auction of the red colour. Engelhart also found that all the iron, mag- 
nesium, and phosphorus, can be extracted from the watery solution of 
colouring matter, or from the coagulated colouring matter suspended in 
water, by passing a stream of chlorine through the fluid, or by mixing it 
with a solution of chlorine in water. The solution of colouring matter 
becomes at first greenish, and then quite colourless ; the animal matter is 
preempted in white flocculi combined with chlorine or hydrochloric acid • 
while the iron, calcium, magnesium, and phosphorus remain in the solu- 
tion, combined either with oxygen or with chlorine,— the iron for ex- 
ample, m the state of chloride of iron, the phosphorus as phosphoric acid, 

and may be separated from it by filtration. The precipitated M . ai 

matter yields no ash by calcination. Now chlorine has no affinity for ox- 
aes, but has a very strong affinity for metals. Moreover iron is not ex- 
tracted from the blood by muriatic and other mineral acids, although these 
acids have a great affinity for metallic oxides, but none for the metals 
tftem se]ves . Hence Berzelius consid e red it more probable that the iron 

m the blood is in the metallic state, not in the state of an oxide, although 
there is no analogous instance known of a quinary combination of a metal 

with *».;** i i -i i 



* Berzelius, loc. cit. p. 58, French translation, p. 61. 
e vera materiae sanguini purpureum colorem imperti 




«. ,. 










M. Rose* has lately adduced new facts in support of the opinion, 
that the iron contained in the blood is in the condition of an oxide. 
Rose repeated Engelhart's experiment. By filtering the fluid after the 
change effected by the chlorine, and after the precipitation of the animal 
matter, the iron could be separated from the fluid ; if, however, it were 
not filtered, but ammonia added in excess, all the precipitate was 
again dissolved and a dark red colour produced, and no iron was thrown 
down. Rose then mixed a solution of colouring matter with a certain 
quantity of persalt of iron, and added ammonia in excess, when the 
peroxide of iron remained in solution, and could be separated neither by 
sulphuretted hydrogen nor tincture of galls. Rose found, moreover, 
that when a persalt of iron is mixed in small quantity with a solution of 
many fixed organic substances, such as sugar, gum,, starch, sugar of 
milk, and gelatine, the peroxide of iron cannot be precipitated from the 
fluid by alkalies. These experiments are certainly in favour of the sup- 
position, that the iron in the colouring matter of the blood is in the state 
of an oxide combined with animal matter. Berzelius, however, is of 
opinion that the kind of combination which in the experiments of Rose 
retains the oxide of iron dissolved in the albumen or colouring matter, 
is not that by which it exists naturally in the colouring matter of the 
blood ; because, were that the case, the iron would be extracted from 
the latter by acidsy as it is from such artificial compounds of colouring 
matter or albumen with peroxide or protoxide of iron, 
acid is added to such an artificial compound, the 
or albumen is precipitated, and the oxide dissolved in the acid. 

Berzelius believes, therefore, that the iron in the colouring matter is 
in the metallic state organically combined with nitrogen, carbon, hydro- 
gen, and oxygen, together with a small quantity of phosphorus, calcium, 
and magnesium ; and that by calcination of the colouring matter its 
elements are oxidised, so as to form phosphoric acid, lime, magnesia, 
and peroxide of iron. The state of the iron in the chyle seems also to 
favour this view; for in this fluid, in which the iron must be in quite a 
different state, — in the state of peroxide, namely, — Emmertf has found 
that it is extracted by nitric acid> and forms then with tincture of galls 
a black, with ferrocyanate of potash a blue, precipitate. 

Meanwhile, GmelinJ opposes this view, which attributes the red 
colour of the blood principally to the iron, admitting even that iron in 
the metallic state be combined with nitrogen, carbon, oxygen, and 
hydrogen, in the colouring matter. He argues, that the discoloration of 
this substance when the iron is extracted, does not prove that the 
removal of the iron is the cause of the discoloration, for the bleaching 
action of the chlorine on the colouring matter may arise simply from its 
extracting the hydrogen so as to leave the oxygen to unite with its 

* Poggendorf's Ann. vii, 81. f Neil's Archiv. 8. £ Gmelin's Chemie, iv. 1169. 

When a mineral 
colouring matter 

■ * 




p components, while the muriatic acid produced by the union of the 
chlorine and hydrogen might then dissolve the peroxide of iron of the 
alkaline fluid. When the serum mixed with colouring matter, 



is treated with excess of cold muriatic or sulphuric acid, 

jnstead of with chlorine, and the colouring matter which is darkened, 

ut by no means bleached, is separated by filtering, peroxide of iron can 

e discovered by means of sulphocyanate of potash in the serum, 

Proving that the oxide of iron may be separated from the 

Wl thout the latter losing its colour. 



O - -~ •- * ~-~w~ «v.« ""iWH U1C ilUIill 

as been removed is evaporated, and the residue boiled repeatedly in 
a ^ oh °l> till very nearly deprived of its colour, this residue when calcined 
1 yields a notable quantity of peroxide of iron. 

* r eviranus has offered a peculiar view of the condition of the iron in 
le blood. Winterl, by carbonising blood with potash, obtained a sub- 
C ^ " # " was soluble in alcohol, and which did not, like ferro- 

stance which 

Fussiate of potash, precipitate iron from its combinations, but coloured 

it red. 



in th e 

becomes of a blood-red colour when mixed with a solution of iron in 
ni tnc or sulphuric acid. The colour produced when I repeated this ex- 
periment was, however, yellowish red, not blood-red. Treviranus sup- 
poses that the substance alluded to, combined with iron, is the cause 

of the red colour of the blood. Gmelin has discovered that „ 

saliva it is sulphocyanic acid that has this action on salts of iron. 
Kuehn, however, doubts this again.* 

Hermbstaedt,t recently, from observing that sulphuretted hydrogen 
is developed during putrefaction in blood and albumen, as well as from 

several experiments, has been led to the conclusion that sulphur is an 
ingredient in the blood. The ash of calcined blood contains an alkali 
which must, Hermbstaedt concludes, be also contained in carbonised 
blood. If, however, carbonised blood be exposed to red heat with 
potash or soda, cyanuret of potassium or of sodium are formed. If C y- 
anuret of potassium or sodium be heated to redness with sulphur, sul- 
phocyanuret of potassium or sodium are produced, which have the 
property of imparting to the peroxide of iron a blood-red colour. In 
fact, serum, solution of albumen, or milk, if treated with sulphocyanic 
acid, become, says Hermbstaedt, of a blood-red colour, on adding a few 
drops of chloride of iron. 



The fibrin has been examined hitherto only in the solid state ; but 
by filtering fresh frog's blood, as I have directed at page 111, we obtain 
** in solution, and by allowing it as it passes through the paper to drop 

* See the Analysis of the Saliva in the 2d book, chap. iv. 
f Schweigger's Journ. 1832, v. and vi. p. 314. 





-- ** - 



into a watch-glass which contains acetic acid, its coagulation is pre- 
vented; or if, in place of acetic acid, the glass contains solution of com- 
mon salt, the fibrin either does not coagulate at all, or only in a 
very small proportion. In the same way the coagulation of the fresh 
blood of the frog is delayed for a very long time, though not entirely 
prevented, by adding to it a solution of common salt. It has been long 
known that certain salts, such as sulphate of soda and nitrate of potash, 
when added in some quantity to fresh human blood, have the property 
of preventing its coagulation. And this in some measure explains the 
action of the cooling salts on the blood in the treatment of inflam- 
mation; they produce some change in the fibrin, which counteracts the 
great tendency that it has in inflammation to accumulate and coagulate 
in the vessels of the inflamed organ and on the surface of membranes 
after exudation. 

It has also been long known that a watery solution of caustic potash 
or soda prevents the coagulation of human blood out of the body. 
According to MM. Prevost and Dumas, the coagulation of the blood of 
the higher animals, when removed from the body, is prevented by the 
addition of as little as xoViyti 1 P art of caustic potash. If the liquor san- 
guinis of the frog's blood, while filtering, is made to drop into a watch- 
glass in which there is some liquor potassae, the fibrin does not coagu- 
late to a clot, but there are slowly formed in it very small flocculi, 
which it requires close inspection to discover. The production of these 
flocculi is still more evident when the watch-glass contains sulphuric 
ether, fresh ether being added in proportion as it evaporates. No 
globules or flocculi are produced in the liquor sanguinis by the action of 
liquor ammoniae. 

Fresh coagulated fibrin may be obtained for chemical analysis by 
washing the coagula which adhere to the twigs with which fresh blood 
has been stirred, or by merely washing the crassamentum. As thus 
obtained, it is specifically heavier than water, serum, or blood deprived 
of its fibrin ; it sinks in all these fluids if it is free from air-bubbles. 
The following description of fibrin is borrowed from Berzelius. 

The coagulated fibrin when washed is white ; by drying, it becomes 
yellowish, hard, and brittle, not transparent, and loses three-fourths of 
its weight. It softens again in water, but is not dissolved. It has no 
particular smell or taste. At the temperature at which it undergoes 
decomposition, it melts, puffs up, and burns, leaving a shining cinder, 
just as is the case with other substances which contain nitrogen. The 
cinder burns to a grey-white, compact, semi-fused ash, which amounts 
to -| per cent, of the weight of the dried fibrin. The ash is neither acid 
nor alkaline : after solution in muriatic acid it leaves traces of silica : it 
consists chiefly of phosphate of lime, some phosphate of magnesia, and 
a very slight trace of iron. The components of the ash cannot be 
extracted from the fibrin, before combustion, by acids, and appear there- 



J to have entered chemically into the composition of the fibrin, and 

is i„,°i Tl ? merely miX6d With h ' In the coa g^ted state, fibrin 
in l t .? b ° th m C ° ld and warm water > but by long-continued boiling 
hard 7 T* 1| COm P° 8ition "^ergoes a change ; it shrivels up, becomes 
n ' f 8 t0 pieC6S ° n the sli S htest Pressure. During this change 

found Y* eVel ° ped; but tbe fluid becomes turbid, and is afterwards 

to contain a newly formed substance derived from the com- 
F ents of the fibrin. The solution of this new substance has no simi- 
Jd nty to solution of gelatin.* 

hav ' 'v C ° agulated albumen > casein, and colouring matter of the blood 
. e this character in common, that they yield no gelatin by boiling 

ln water, 

(not albumen,) 

* Property of decomposing peroxide of water by mere contact ; oxygen 

If th g d6Veloped and water formed > while the fibrin remains unaltered. 

e quantity of fibrin is large, heat is at the same time developed. 

^ ' h acids and alkalies it unites, playing in the one case the part of 

ase, ln the other that of an acid, at least of an electro-negative 

nee. W 

acted on by the acids in the same 


„ i . . ^.« .*, owciio up, loimiug a, transparent 

8 atinous acid substance ; with diluted acids it forms a neutral com- 
Fund contracting considerably at the same time. The acid compound 

soil T neral add is insolubIe in w ater, the neutral compound is 
omble . while both the neutral and acid compounds with acetic acid 
e soluble. The ferrocy an ure t of potassium, when added to the 
so ution of fibrin in acetic acid, throws down a precipitate, which is 
characteristic of fibrin ; this not being the case with cellular tiss 
tendinous structure, and the elastic tissue of arteries. Albumen 
n _ „ way as fibrin. According to 

Caventou and Bourdois, fibrin, albumen, casein, and mucus, are dis- 
solved by cold concentrated muriatic acid, and if kept at a temperature 
of from 64° to 68° Fahr. acquire after twenty-four hours a beautiful 
blue colour ; while this effect is not produced on gelatin and the sub- 
stance of tendons. If the fibrin used in this experiment had not been 
perfectly freed from the colouring matter, the fluid, instead of being 
wue, was purple or violet. Fibrin, albumen, and casein, also agree in 
eing dissolved to a gelatinous mass by caustic potash and soda, without 
emg, like horn, converted into a soapy substance. The gaseous ele- 
ments of fibrin according to the analysis of Gay-Lussac and Thenard, 
and that of Michaelis, are combined in the following proportions • 

Gay-Lussac and Thenard. 



















* Berzelius, loc. cit. pp. 35, 36. 

t See also Berzelius, loc. cit. pp. 34-47. E. H. Weber, loc. cit. p. 83. 






jr ' 



Besides in the blood, fibrin also exists in solution in the chyle and 
lymph, and the muscles and uterus contain it in the solid state. In the 
fibres of the arteries, however, there is no fibrin. 


Besides the salts, J-* of its 



3. The Serum. 


If the coagulum formed by exposing serum to a temperature of 
169° Fahr. be dried and then treated with boiling water, and the 
residuum left on evaporating the solution thus obtained be afterwards 
acted on repeatedly with alcohol, the alcohol will be found to take 
up lactate of soda, chloride of potassium and sodium, and osmazome ; 
while the substance, which neither the boiling water nor alcohol dis- 


solves, is pure albumen. The animal matters of the serum are, there- 
fore, lactic acid, osmazome,, and albumen. 

All the components of the serum, with the exception of the albumen, 
are obtained in solution in a small quantity of water when freshly coa- 


gulated serum is subjected to a gentle pressure. The clear fluid which 
then exudes has been called "serosity." 
weight is animal matter, which according to Brande is albumen, at least 
in part, it being coagulated by the action of galvanism. Dr. Bostock, 
however, maintains, that, if the serosity is in a pure state, it contains no 
albumen, but merely what Dr. Marcet and Thouvenet have called muco- 

extractive matter or osmazome.*] 

This acid is composed of carbon, hydrogen, and 

oxygen ; it has some analogy with acetic acid, but according to Ber- 
zelius is quite distinct from it. It forms with bases, salts of peculiar 
form, which Berzelius says are not produced by acetic acid rendered 
impure by animal matter. Pure lactic acid, prepared by the method 
most recently described by Berzelius, is colourless, without smell, and 
has a pungent acid taste, which is very quickly diminished by addition 
of water. It is soluble in alcohol in all proportions, while ether dis- 


solves it in a small quantity only. It is found in muscle and in the 
crystalline lens, and, with its salts, occurs in many secretions, parti- 
cularly in the milk. Lactic acid and its salts are always combined 


with osmazome, are extracted together with it by alcohol, but can be 
separated from it by means of infusion of galls, which precipitates the 


(2.) Osmazome^ or animal extractive of Thouvenet, is soluble both in 
water and alcohol, whether they be hot or cold ; it deliquesces in a 


damp atmosphere, melts in a warm air, and is precipitated from its solu- 
tions by infusion of galls. Osmazome is found by Gmelin to exist also 
in saliva, and in the pancreatic and gastric juices. Berzelius regards 
osmazome not as a peculiar substance, but as a compound of an animal 
matter with salts of lactic acid. 

* Dr. Bostock's System of Physiology, p. 292. 

» * 




(3.) Albumen. — The substance which remains after the extraction of 
the lactic acid and the osmazome from the dried coagulum of the serum 

,s albumen. It is also an ingredient in lymph and chyle, in the white 
an d yolk of the egg, (in the latter mixed with oil,) in the exhalations 
°f the serous membranes, in the fluid of the cellular tissue, in the 
a queous and vitreous humours of the eye, in the brain and nerves in 
c onibination with fat containing phosphorus, and in the contents of the 
Graafian vesicle of the ovary of mammalia and man. Here we have 
to consider principally the albumen of the serum, and this in two states. 
#• Albumen in the state of solution. — In the serum it is in combination 
Wl th soda, forming what is called albuminate of soda. Berzelius does 
n °t believe that the albumen of the serum is held in solution by means 
of the soda, for the soda may be saturated with acetic acid, without any 
precipitate being produced. Stromeyer found that ten drops of distilled 
vinegar are necessary to neutralise half an ounce of blood. If serum 
or solution of albumen be evaporated at a temperature below 140° Fahr. 
he albumen is left dry and transparent, and is in that state soluble in 
w ater. At a temperature between 158° and 167° Fahr. the albumen 
Coa gulates, and is then insoluble in water. 

11 serum be mixed with a large quantity of water, it no longer 
^comes solid by heat, but coagulates in globules, so as to form a 
1J ky fluid, which, however, when evaporated, yields coagulated albu- 
men with the usual characters. Albumen is coagulated by the action 
or the galvanic battery, by alcohol, mineral acids, metallic salts, — for 
example, by salts of tin, lead, bismuth, silver,, and mercury, — by chlo- 
rine, and by infusion of galls ; and the same effect is produced on the 
albumen of the serum, according to the observations of Dutrochet and 
myself, by a very concentrated solution of fixed alkali,— for example, 
coagulation is produced when a small quantity of serum is mixed with 
a large quantity of liquor potassae. White of egg, however, I find, is 

not coagulated by the liquor potassse unless it (the white of egg) is in 

lts undiluted state. Liquor potassae precipitates also the albumen of 

yraph and chyle. Albumen of the egg is coagulated by pure ether, 

^vhich produces no precipitate in serum. This was first observed by 

me hn, and I have since seen it confirmed. 
*y experiments on the fibrin in the fluid state as it exists in the 

00 * lave afforded me data for comparing it with albumen in a state 

solution. Acetic acid produces no precipitate in serum, and none 

al so in the solution of fibrin; thus the liquor sanguinis of frog's blood 

allowed to drop from the filter into acetic acid does not coagulate. 

Th ... 

in e neutral salts produce no precipitate in serum; and many of them 
a s the carbonates of potash and soda, nitrate of potash and sulphate 
°f soda, — prevent the spontaneous coagulation of fibrin. Common salt 
has the same effect on the fibrin in frogs blood. Liquor ammoniae 



* . +* 



produces no precipitate in the fibrinous fluid obtained by filtration from 
frog's blood, any more than in solution of albumen or serum. Liquor 
potassas precipitates the albumen from serum, and likewise precipitates 
in small flocculi the fibrin of the liquor sanguinis when this fluid is 
allowed to drop from the filter into a watch-glass containing liquor 
potassae. Ether produces no precipitate in serum, but the fibrin coa- 
gulates when the liquor sanguinis of filtered frog's blood drops into 
a watch-glass containing ether. The coagulation of fibrin by HquoF 
potassae or ether differs from its spontaneous coagulation, inasmuch 
as in the latter case a completely coherent coagulum is formed which 
is at first transparent and gradually becomes turbid or opaque, while in 
the artificial coagulation the fibrin takes the form of separate globules, 
as is often the case with albumen when coagulated. The principal dif- 
ferences between the solution of fibrin and that of albumen in the serum, 
are, that the former coagulates spontaneously, while albumen coagulates 
only under the action of heat or certain reagents, and that the fibrin is 
precipitated by ether in the form of globules, while the albumen is not. 

If albumen in solution is mixed with acids or alkalies, the part which 
unites with the reagent undergoes the same change as when it is coagu- 
lated, even although the reagent does not precipitate it ; thus it is pre- 
cipitated from the solution in acetic acid when potash is added, and 
from the alkaline solution on the addition of acids, just as is the case 
with colouring matter under similar circumstances. 

If a small quantity of a metallic salt is mixed with serum, and a rather 
larger proportion of caustic potash added than is necessary for the de- 
composition of the metallic salt, the oxide is not precipitated, but re- 
mains in solution combined with the albumen. Berzelius, who men- 
tions this, remarks that it is by this means that metallic salts, or oxides, 
are absorbed from the intestinal canal or the skin, carried into the circu- 
lation, dissolved in the serum, and expelled with the excretions; and 

hence it is that after the continued use of mercury we find the protoxide 
dissolved in the fluids of the body.* Would not the extremely intimate 
combinations of the metallic oxides with albumen be useful 
medicine? Albumen or serum coagulates when mixed with concen- 
trated solutions of earthy or metallic salts, and the coagulum contains 
the components of the salt These coagulated combinations of albumen 
with salts also deserve a greater attention in medicine. Among the 
metallic salts already mentioned, the acetate of lead, and still more the 
bichloride of mercury, are remarkable as being the most delicate tests 
for albumen. Corrosive sublimate renders turbid a fluid which contains 
on ty Woo** 1 P art of albumen in solution. From its great tendency to 
unite chemically with this salt, albumen is an antidote for it. 


* Autenrieth and Zeller, Rett's Archiv. via. Schubarth, Horn's Archiv. 1823, 
Nov. 417. Cantu, Mem. d. Tor. 29. 1825. Buchner s Toxicol. 538. 


■ i 





b. Albumen in the coagulated state y in which it consists of aggregated 
globules. In this state albumen has the same chemical properties as 
«brin, and Berzelius knows no chemical test to distinguish them, except 
"tot coagulated albumen does not decompose the peroxide of water. 
Iheir elementary composition also differs little, as is seen by comparing 
the analyses of albumen given by Gay-Lussac and Thenard, Michaelis, 
and Prout, with those of fibrin given at page 127 

Gay-Lussac and Thenard, 

Carbon . 








Arterial. Venous. 

15-562 . 15-505 

Prout . 










Berzelius found the proportion of the albumen to the other compo- 
nents in 100 parts of the serum of human blood to be as follows : 

Water . . 


Osmazome, with lactate of soda 

Chloride of sodium 

Extracted by alcohol 

Modified albumen — alkaline, > ^ . .* v 

y \ Extracted by water 

carbonate, and phosphate 





In^addition to these ingredients, Lecanu has found in the serum the 
sulphate of an alkali, carbonate and phosphate of magnesia, and phos- 
phate of lime. Berzelius conjectures that the three principal components 
of the blood, fibrin, colouring matter, and albumen, are only modifica- 
tions of one and the same substance ; that the colouring matter, for 
example, may owe its peculiarity to the iron it contains. Treviranus 
is of the same opinion. 

4. Fatty matter of the blood. 

In some rare instances the blood contains fatty matter in a free state 
which we then see floating on the surface ; but the fatty matter of the 
blood is for the most part combined with the fibrin, colouring mattei 
a nd albumen. If the mixture of serum and red particles, obtained by 
stirring bullock's blood, be boiled with alcohol, and then filtered, the 
nrst portions of the fluid are found by Gmelin* to contain cholesterine, 
stearine, elaine, and stearic acid. Berzelius was formerly of opinion, that 
this fatty matter was formed during the chemical process. But it is 
m ost probable that fat is really contained in the fibrin, albumen, and 
colouring matter, and is merely extracted from it by the process of 
boiling in alcohol, for the chyle from which the blood is formed contains 
fatty matter in the free state, in the form of emulsion ; and during the 

* Chemie, iv, 1103. 

K 2 

I i 




formation of the blood this fatty matter unites probably more intimately 
with the other animal matters. Chevreul has by means of ether sepa- 
rated from fibrin a fatty matter, analogous to that which we obtain from 
the brain, and like that chiefly remarkable from containing phosphorus in 
a combined state. Berzelius also is now of opinion, that the fatty matter 
is only extracted, not produced, by the analysis ; and he is led to this 
opinion more especially from observing that the fibrin is not chemically 
changed by the extraction of the fat by ether or alcohol, and that after 
the usual small quantity of fat is separated, no more can be obtained by 
continuing the process. The fatty matter of fibrin is, according to Ber- 
zelius, in a saponaceous state, for its solution in cold alcohol reddens 
litmus paper ; a proof that at least a part of it must be in the state of 
an acid, as is the case after the process of conversion of a fat into soap. 


Berzelius describes two modifications of the fatty matter of fibrin, and 
concludes with the remark, that it has great resemblance to the acid 
salts of stearic and elaic acids with potash, described by Chevreul, ex- 
cept in its greater solubility in ether and alcohol. According to Che- 
vreul, the fatty matter in fibrin amounts to 4 or 4^ per cent. Lecanu 
found a crystallisable fatty matter, and an oily matter in the blood ; of 
the first there were from 1-20 to 2-10 parts, of the latter from 1-00 to 
1 30 parts in 1000 parts of serum. Boudet* confirms Gmelin's state- 
ment that the blood also contains cholesterine. 

All kinds of fat are remarkable from the small quantity of oxygen, 
and the preponderating quantity of carbon, which enter into their com- 
position. It is also remarkable that the fatty matters, — elaine and 
stearine, — which occur in the body in the free state, always combined 
one with the other, contain absolutely no nitrogen. Elaine and stearine 
are soluble in ether and hot alcohol, and the elaine remains dissolved in 
the alcohol even after it has cooled. 









Other fatty matters, — for instance, that of the blood, — are combined 
with other animal substances, they crystallise in part when exposed to 
the cold, contain nitrogen, and cannot be converted into soap. The 
fatty matters of the blood and brain contain phosphorus also. Fatty 
matters of this kind occur in a combined state in the blood, cerebral 
and nervous substance, in the liver, and perhaps in some other parts. 

If the new organic matters formed by the secretions, — 
picromel, casein, mucus, &c. — are not taken into consideration, the 
blood will be found to contain the proximate elements of all the solid 
parts of the body, — namely, fibrin, albumen, osmazome, lactic acid, and 

* Essai Critique et Experimental sur le Sang. Paris, 1833. 





y matter* The only exception is the gelatin or gluten which is 
obtained from the tendinous fibres, cartilages, bones, serous membranes, 
a nd from the cellular tissue generally, particularly from the cellular 
tissue of the muscles. Parmentier and Deyeux, and Saissy thought, 
indeed, that they had discovered gelatin also in the blood. But this 
w as evidently an error. It is a question, however, whether gelatin 
generally is not formed during the changes produced in the composi- 
tion of the tissues by boiling. Gelatin is obtained from the parts 
Mentioned by boiling water : it is insoluble in alcohol and cold water, 
by which it is distinguished from osmazome: it forms a jelly on 


cooling even when dissolved in one hundred and fifty times its weight 
°f water: in this jelly it is combined with water, and is again soluble in 
boiling water, by which it is distinguished from fibrin and albumen. It 
*s slowly soluble in acids and alkalies, and is precipitated by tannin and 
chlorine. E. H. Weber has stated several facts which render it proba- 
ble that gelatin does not originally exist in the body, but is formed by 
e decomposition of other animal matters, in which opinion Berzelius, 


Pr ochaska, and Ficini 

us concur. The strongest argument in favour of 

this opinion is, that, according to the statement of Berthollet, flesh of 
an imals, which by boiling in water has ceased to afford gelatin, reac- 
quires that property after undergoing putrefaction in a close air with 
developement of carbonic acid.* 



Dutrochet has made some ingenious experiments respecting the 
action of galvanism on animal substances. He even flattered himself 
that he had formed muscular fibres from albumen by the agency of 
galvanism, and supposed that the red particles of the blood formed each 
a pair of plates, the nucleus being negative, the envelope positive. But 
all the appearances which he has attributed to different electric proper- 
ties of the blood are explicable by the precipitation of the albumen 
and fibrin in consequence of the decomposition of the salts of the serum, 
and of the oxidation of the copper wire used in the experiments — both 
th e decomposition of the salts and the oxidation of the copper being the 


consult Wienholt. Meckel's Archiv. i. p. 206. Berzelius, loc. cit. p. 661. The 
French translation, p. 703. 

T The original observations are in Poggendorf's Annal. 1832, 8, 

+ [The translator has conceived it to be better to place the long detail of experiments, 

which the author enters into for the purpose of refuting Dutrochet's erroneous views, 

l n the form of a note, giving in the text merely the inference that he deduces from 

the experiments.] 

If a drop of a watery solution of yolk of egg (in which very minute microscopic 

globules are suspended) be submitted to the action of galvanism, we soon remark the 


i ■ 




Should any physiologist be so fortunate as to prove beyond doubt the 
electric property of the blood, I could only congratulate science on the 
great advance which it would thus have made. Till then it is proper to 


submit to severe criticism all experiments which do not justify the con- 

waves (ondes) which were first observed by Dutrochet (Ann. d. Sc. Nat. 1831). The 
wave originating at the copper or negative pole, is transparent on account of tbe al- 
bumen being dissolved by tbe alkali ; wbile that commencing at the positive or zinc 
pole where the acid collects, is opaque and whitish, particularly near the wire. The 
two waves tend towards each other, and at the moment of contact a linear coagulum 
is suddenly formed along the line at which the two waves meet, and has therefore ex- 
actly the form of that line j it is waving like the border of the two undulations at the 
moment of their meeting, A visible movement attends the formation of the coagu- 
lum ; as soon, however, as it is formed, all is still, and not the slightest movement 
is afterwards perceptible. It is therefore difficult to conceive how an observer of 
the first rank, like Dutrochet, could pronounce this coagulum of albumen to be a 
contractile muscular fibre produced by electricity. It is nothing more than coa- 
gulated albumen, and is quite soft, like the albumen which collects around the zinc 
wire in galvanising serum. It consists of globules which can be easily wiped asunder, 
and which have been merely deposited in the form of the line of contact of the two 
currents without any cohesion. If both wires are placed in a drop of serum, whether 
of the blood of the frog or of one of the mammalia, no distinct waves are perceptible ; 
but a deposition of globules of albumen takes place at the zinc wire, and gradually 
increases, the globules first deposited around the wire being pressed outwards, while 
a new deposition takes place. According to the view which Dutrochet takes of the 
action of galvanism on animal substances, we must consider the albumen of the 
serum as a negative electric body, since it is deposited at the zinc or positive pole of 
the battery. But the real cause of its precipitation is the coagulation of the albumen 
by the acid which is derived from the decomposition of the salts, and collected at the 
positive pole. The albumen is not deposited around the negative wire, because it is 
there held in solution by the alkali. By a very powerful battery, however, the albu- 
men is precipitated at the copper wire also, as Gmelin has pointed out : this depends 
either upon the heat developed, or, what is more probable, on the circumstance of a 
concentrated solution of a fixed alkali, having the power of precipitating albumen, a 
fact observed both by Dutrochet and myself. The difference of the quantity of the 
salts in the two fluids clearly explains why with a battery of the same strength albu- 
men is copiously precipitated around the zinc or positive wire in the serum, while in 
solution of yolk of egg merely a turbid undulation is perceived, and no coagulum is 
found until this undulation meets that from the negative pole. Lassaigne (Ann. d. 
Chim. et d. Phys. t. xx. p. 97. Weber's Anat. t. i. p. 87.) coagulated albumen by al- 
cohol then washed it with the same fluid until chloride of soda could be no longer de- 
tected in it by means of nitrate of silver. Of the coagulum thus free from salts, 
water took up — \^ y and the small quantity of albumen thus dissolved did not coagu- 
late under the influence of galvanism, because it contained no muriate of soda : it co- 
agulated when this salt was added. 



whereas the albumen of the serum would be negative electric, for it coagulates at the 
positive pole. But we need only add to the solution of the yolk of egg some common salt, 
and it coagulates at the positive pole, and no currents are formed. If we expose to 
the action of a galvanic pile a drop of the blood of a frog, or of a mammiferous animal, 



elusions deduced from them : the conclusions being but too readily ad- 
mitted by those who do not repeat the experiments 

I have already mentioned that with the galvanometer no electric 
current can be discovered in the blood ; I perceived no variation of the 


pread thinly out, the usual gaseous bubbles are formed around the copper wire, and 
around the zinc wire the albumen coagulates to a soft mass of granules, just as when 
serum is treated in the same manner. The red particles, on the contrary, do not collect 
either at the positive or at the negative pole- The coagulation of the fibrin is neither 
accelerated nor retarded ; it takes place neither around the positive nor the negative 
P°le particularly, but throughout the entire drop between the two wires, and in the 
Clr cumference of the fluid at some distance from them. Immediately around the 
wires the red particles are decomposed by the acid and alkali collecting there. In the 7 
other parts of the drop they suffer no change. The coagulation of the fibrin takes 
place in the same way when arterial or venous blood of the rabbit is used instead of 
frog's blood. 

When a drop of frog's blood from which the fibrin has been removed, is exposed to 
the action of galvanism, it presents the same phenomena as fresh blood, with the ex- 
ception of those dependent on the presence of fibrin. If a drop of the strongest possible 
solution of colouring matter, obtained by washing the crassamentum of the blood of 
quadrupeds which has been previously freed as completely as is possible from the serum 
it contains by means of blotting paper, was subjected to the voltaic pile, I obtained 
liferent results according as I closed the circle with the copper wire itself, or fixed a 
Piece of platinum wire on the extremity of it, so that the quick oxidation of the copper 
might not interfere with the experiment. In the last case the results were the same as 
those described by Dutrochet ; in the first case they were different. When I used a 
ware copper wire to close the circle, a red pulpy coagulum of albumen and colouring 
matter formed around the zinc wire. The coagulum gradually increased by new depo- 
sitions around the zinc wire, extending the original red ring. The later depositions were, 
however, less red than the first — mostly of a whitish grey colour. The coagulation takes 
place all around the zinc wire, but extends rather further in the direction of the cop- 
per wire than in other directions. The precipitate has the form of the wave in the 
preceding experiments, but is formed of a consistent pulp. At the copper wire the 
usual developement of gas is remarked, and sometimes a very indistinct undulation, in 
which the colouring matter remains dissolved, as in the rest of the fluid : the border 
of this undulation is of a somewhat deeper red than the rest of the fluid. Dutrochet 
calls this a red wave, but for this there is no reason. The alkali which collects around 
the negative wire usually holds in solution the animal matter of the fluid, which, in 
this case, contains red colouring matter in solution, as does the rest of the fluid, while 
around the positive pole the albumen and colouring matter coagulate. The descrip- 
tion which Dutrochet gives of the effects of galvanism on the solution of colouring 
matter is quite different. (See Froriep's Notiz, No. 715.) Thus, he says, that two 
undulations appear ; the one at the zinc pole was acid and transparent, and, as it in- 
creased, drove before it the colouring matter, which collected in the upper part of the 
fluid around and beyond it ; the alkaline wave at the copper pole was on the contrary 
occupied by the colouring matter. The two waves formed in uniting a slight coagu- 
lum derived from the albumen of the serum removed from the crassamentum with the 
colouring matter. The red colouring matter combined almost wholly with this 
coagulum. From this experiment, in which the red colouring matter is said to retire 
from the positive pole and collect at the negative pole, Dutrochet without reason con- 
cludes that this substance is an electro-positive body. I have already stated that 


1 1 

r * 

. . . ■ 




magnetic needle of the multiplicator, even when I inserted one wire 
into an artery of a living animal, the other into a vein. Bellingeri be- 
lieved that he had discovered a means of proving the electric property 
of the blood by the contractions excited in the leg of a frog., when 


when I used copper wire to close the circle, the colouring matter coagulated with the 
albumen around the zinc pole, and the red coagulum by further coagulation of the 
albumen was only further extended. If, however, I put a piece of an unoxidisable 
metal, as platinum, on the end of the copper wire, to avoid the influence of the oxidation 
of the latter, the appearances were exactly those described by Dutrochet. There were 
now really formed at the copper and zinc poles two waves which tended towards each 
other, each wave having a distinct red border. Dutrochet overlooked the red border 
in the wave of the copper pole. The wave of the copper pole is not redder than the 
rest of the fluid ; it is its border only which is redder. Dutrochet is therefore incorrect 
when he says, the colouring matter accumulates at the copper pole. I have repeated 
the experiment very often, and have never seen this accumulation take place. The 
red colouring matter in the red border of the wave of the copper pole retires, indeed, 
in some measure from the copper wire, as that in the border of the wave of the positive 
pole does from the zinc wave. Although the undulation from the negative pole is not 
redder than the rest of the drop, that of the positive pole, on the contrary, is in fact 
less coloured than the fluid beyond the wave, but yet not quite colourless. The border of 
the more transparent wave of the positive pole is redder than that of the wave of the 
negative or copper pole, which is, however, itself remarkable from its deeper colour : in 
the border of the wave of the copper pole the colouring matter is in the state of a concen- 
trated solution ; in the margin of the wave of the zinc pole the colouring matter is in 
the form of very small globules. This experiment appears to me to be very similar to 
that in which solution of yolk of egg is exposed to the action of the voltaic pile. If in 
the experiment on the solution of colouring matter bare copper wire is used to close the 
circle, the colouring matter and albumen coagulate at the zinc pole. If common salt 
be added to the solution of yolk of egg P the albumen coagulates at the zinc pole. If 
common salt is mixed with solution of colouring matter, it is acted on, even with the 
platinum wire, like the solution of yolk of egg with common salt ; no waves are formed, 
and a whitish coagulum collects at the zinc pole. All these facts being considered, 
Dutrochet's assertion that the colouring matter of the blood is electro-positive, appears 
to me unfounded. 

Dutrochet having obtained some fibrin free from colouring matter, by washing the 
crassamentum, which he incorrectly regards as formed by the aggregation of the nuclei 
of the red particles, dissolved it in a weak alkaline solution, and then subjected it to the 
action of a voltaic pile : hydrogen was developed in considerable quantity at the negative 
pole ; at the positive, oxygen ; but at neither was any undulation formed : the fibrin coa- 
gulated at the positive pole only ; whence Dutrochet concludes that the alkaline solution 
of fibrin is acted on as a neutral salt, of which the alkali passes over to the negative pole, 
and the acid to the positive, and therefore that the fibrin is a negative electric substance. 
We know, however, that fibrin can unite both with acids and alkalies ; in the one 
acting the part of a base, in the other that of an acid. From its forming neutral com- 
pounds with mineral acids, we might have come to a conclusion the very opposite of that 
of Dutrochet. However, in repeating Dutrochet's experiments, as might be expected 
from so exact an observer, I found them in most points correct. When I exposed a so- 
lution of fibrin of the blood in a weak alkali, on a glass plate or in a watch-glass, to the 
action of the voltaic pile, a white pulpy coagulum was deposited in small quantity at 
the positive pole. I had washed the fibrin, obtained by stirring bullock's blood for a 






a circle, formed of blood, the nerve and muscle of the limb, and a metal, 
] s closed by bringing the blood and metal in contact. He set out from 
the principle, that by contact of two heterogeneous bodies the electricity 
present in them is thrown into a state of greater or less tension, and 



n g time on the filter, so that I could be pretty sure that it was free from serum and 

1 e salts of serum: it appears therefore, at first view, that the alkaline solution of 

nndoes really separateinto electro-negative fibrin and electro-positive alkali. In c6ming 

jus conclusion, however, the mineral substances and salts which are ingredients in the 

1111 x tself are lost sight of ; their decomposition by the galvanic pile would necessarily 

e at tended by the developement of acid at the positive pole, and therefore might cause 

e n brin to coagulate by forming with it a neutral substance. However, there are still 

jections which may be urged against the value of the experiment itself. The effect 

escribed by Dutrochet only occurs when copper wires are used. I never observed it, 

0u gh I made the experiment repeatedly, when, to prevent the oxidation of the end of 

e copper wire of the zinc pole, a piece of platinum wire had been affixed to the end of 

• -Dutrochet seems to have made his experiments merely with copper wires. If 

P atmum wire is used at the positive pole, the developement of gas remains the same ; 

m eed, still more gas than before is formed at the positive pole, because it no longer 

0X1 lses tne copper wire as before. But not the slightest trace of a coagulum is formed 

the zmc pole or around the platinum wire. Hence we must conclude that the 

ormation of a coagulum from an alkaline solution of fibrin, at the positive pole, when 

* e copper wire is used, is dependent on the oxidation of the copper. 

t appears then that the alkaline solution of fibrin is not decomposed by the galvanic 
P 1 e, unless copper wire, which so readily suffers oxidation, is employed at the zinc pole ; 
an therefore that fibrin is not proved to have the character of an electro-negative body. 
. 0W muc h the precipitation of the albumen and fibrin depends on the salts contained 
m e s °hrtion, i s shown by the following circumstances : — Alkaline solution of fibrin 
never deposits the slightest coagulum around the platinum wire of the zinc pole • but 
this coagulation takes place immediately that some common salt is added to the solution 
the muriatic acid of the salt in that case causing the coagulation at the zinc pole : con- 
sequently, before making experiments with galvanism on a solution of fibrin in a weak 
alkali, the fibrin must be completely free from serum, for serum contains muriate of 
soda. We may obtain it thus pure by washing the coagulum, obtained by stirring 
blood, for a long time with a large quantity of water. 

^ It occurred to me that it would be very interesting to try the action of the galvanic 
Pile on the still fluid fibrin of the liquor sanguinis. For this purpose, equal quantities 
of distilled water and frog's blood were poured into the filter (as described at page 111), 
and the fluid which passed through was immediately subjected to the wires of the gal- 
vanic pile. At the zinc pole a pulpy coagulum of albumen was immediately formed, 
he transparent fibrin collected at neither pole, but coagulated in the middle of the 
uid in the watch-glass, in the form of an isolated clot, quite unaffected by the action 
the galvanic apparatus. It coagulated in the usual time. The albuminous deposit 
a t the zinc pole was of the same kind as I had obtained it by application of the galvanic 
Pue to blood freed from the coagula of fibrin. 

I have also tried the action of the voltaic pile on the colourless nuclei of the red par- 
tl cles of the frog's blood. The red particles were freed from their coating of colouring 
Matter, as already described, by means of a large quantity of water. The greatest 
Part of the supernatant fluid was taken up again with a syphon, and the white sedi- 
nient being then mixed with some water, a drop spread upon a glass plate was subjected 
to the action of galvanism. The same phenomena were produced as when a watery 




that this tension is so much the greater the more distant these bodies 
are one from the other in a scale in which they are arranged according 
to their electrical properties. Bellingeri arranged the metals in the fol- 
lowing order : — zinc, lead, mercury, antimony, iron, copper, bismuth, 
gold, platinum. He compared the electrical property of the blood with 
that of the above-mentioned metals, blood being brought into contact 
with one of the metals, and the blood and metal with the nerve and leg 
of the frog, when the contraction of the frog's leg served as electro- 
meter. He had found, he says, that when two metals are brought into 
contact, respectively with the nerve and muscle of a frog which had 
already lost some portion of its irritability, that metal is positive with 
regard to the other, which when applied to the muscle excites con- 
traction at the moment that the circle is closed, and either not at all, or 
only at the moment of interrupting the circle, when applied to the nerve. 
(The reverse, however, is the fact.) M. Bellingeri asserts, that when 
he tested the electric property of the blood in this way, substituting it 
for one of the metals, he found that it stands in different relations to 
different metals, and that in general it evidenced the same electric pro- 
perty in relation to the other metals as iron. Arterial and venous blood 
did not differ in this respect. The electric property of the blood is pre- 
served, he says, long after its abstraction from the vessels.* It is incon- 
ceivable how any great value can be accorded to these experiments. I 
have already recounted the experiments which I made on the frog in 
the spring before the breeding season of the animal ; when by laying 
the nerve of the frog's leg in a small saucer containing blood or water, 
(it was indifferent which,) and bringing the muscles of the leg and the 
blood in contact by means of a piece of copper wire, a contraction in the 
leg of the frog was produced. In repeating this experiment now in the 
cold season of autumn (end of October), I obtain the same results, and 
am convinced that the rare electric phenomena already relatedf are 


solution of yolk of egg is exposed to the same influence : two waves were formed ; that 
of the zinc pole was turbid and drove before it the minute globules, that of the copper 
pole was transparent and contained no globules. When the experiment was made 
with solution of colouring matter, the wave arising at the zinc pole drove before it red 
globules, while in this mixture of nuclei of the red particles with water, the particles 
at the margin of the same wave were white. This experiment shows that there is no 
electric difference between the nucleus and its envelope. The only apparent difference 
was, that the wave at the zinc pole in the solution of colouring matter was more trans- 
parent, while in the mixture of nuclei of the red corpuscules and water, as in the so- 
lution of yolk of egg^ which also contains globules, it was turbid. 

While I differ from Dutrochet in many points in the results of my observations, I 
must express my admiration of the ingenuity displayed by this talented inquirer in en- 
deavouring to solve this difficult question. 

* Froriep's Notiz. 408. See also page 73 of this work. 

t Page 00. 



Produced, not merely before the time of pairing in the spring, but also 
with the same facility in the cold autumn season. In this experiment 
J s evident, that a circle of copper and water between the nerve and 
Muscle is perfectly as efficient as one of copper and blood. What then 
a s Bellingeri proved if the electric quality of water is the same as that 
blood? It is, indeed, very probable, that neither the blood nor the 
w ater excites the electricity in this circle ; they may be mere conduc- 
es, the electricity being developed between the copper and the 





a. The vivifying influence of the blood. 

The arterial blood in its course through the capillary vessels of the 
body loses its bright red colour and becomes a^ain venous. The 

unknown reciprocal action between the blood and the organised matter, 
y w hich this change is effected, maintains the vitality of the organs, at 
tne same time that it renders the blood incapable of again exercising 
this necessary vital stimulus until it has regained its arterial character 
*n the lungs. In the process of arterialisation, the blood absorbs oxygen 
from the atmosphere and gives out carbonic acid, — the oxygen which it 
absorbs being in greater quantity than the carbonic acid exhaled. The 
same portion of blood acquires and again loses its arterial properties 
within the period of a few minutes ; for it will be shown at a future 
page, that the blood circulates through the whole body in that space of 
time. It is only while in its arterial state that the blood is capable 
of maintaining life. The suppression of the change which the blood un- 
dergoes in the lungs produces asphyxia and death, chiefly, as Bichat has 
shown, by interrupting the functions of the brain and nervous system. 
The necessity for arterial blood is less urgent, however, in new-born 
children, and still less so during the state of hybernation and torpor, and 
*n the lower animals ; in the foetus of the mammalia the necessity for 
the aeration of the blood seems to be wholly wanting. The functions 
uiost dependent on the arterial state of the blood are those of the ner- 
vous system, and those of animal life generally. This is evidenced by 
the symptoms of the morbus coeruleus, in which the two kinds of blood 
continue, from some defect in the circulating organs, — for instance, 
a persistence of the canal in the ductus arteriosus, or of the foramen 
ovale, — to be partly mixed. Nutrition and secretion are here little 
interfered with, even although the surface is dusky and blueish : but the 
muscular power fails ; the slightest exertions bring on symptoms of suffo- 
cation, fainting, and even asphyxia ; the sexual passion is not developed, 

i 1 1 

■ I 





the temperature is lower than natural, and there is a tendency to he- 
morrhage even to a fatal extent.* That arterial blood is not so neces- 
sary for the performance of the functions of organic life is moreover de- 
ducible from the fact, that secretions are in some cases formed by 
organs which receive a much larger quantity of venous than of arterial 
blood. Thus the bile is secreted in part from the venous blood of the 
porta, the urine in reptiles and fishes in greater part from the venous 
blood which in these animals is carried to the kidneys by afferent veins 
which are independent of the arteries, and of the efferent veins that re- 
turn the blood to the heart. 

The application of a ligature to all the arterial trunks of a limb de- 
prives it of power of motion, and at last of vitality. Great losses of 
blood produce immediate asphyxia in the higher animals : cold-blooded 


animals, however, survive for a considerable time the abstraction of the 
greater part of their blood, and frogs live many hours even after the re- 
moval of the heart, and retain perfect power of motion. But even parts 
which have been removed from the body, and have lost their irritability, 
appear to recover in some degree their vitality by immersion in blood, 
as in the case of the heart of the frog in Von Humboldt's experi- 

Transfusion of blood. — -Prevost and Dumas showed that the vivifying 
power of the blood does not reside so much in the serum as in the red 
particles. An animal bled to syncope, is not revived by the injection of 
water or pure serum of a temperature of 68° Fahr. into its vessels. But 
if blood of one of the same species is used, the animal seems to acquire 
fresh life at every stroke of the piston, and is at last restored. Professor 
Dieffenbach has confirmed these experiments. It is stated by Prevost 
and Dumas, and by Dieffenbach, that revival takes place likewise when 
the blood injected has been previously deprived of its fibrin. I have 
shown that the red particles of the blood remain perfectly unchanged 
after the removal of the fibrin ; blood, therefore, from which the fibrin 
has been removed, and heated to the proper temperature, ought to be 
preferred in the few cases where transfusion of blood is justifiable, or 
necessary, on account of hemorrhage ; for in this state the blood is com- 
pletely fluid and remains so, and thus the principal difficulty of transfu- 
sion, namely, the ready coagulation of the blood in passing from one 
animal to the other, is avoided. Blood of animals of a different genus, 
of which the corpuscules, though of the same form, have a different 
size, effect an imperfect restoration, and the animal generally dies in 
six days. The pulse becomes quicker, the breathing remains natural, 
but the temperature sinks very rapidly ; the excretions are mucous and 

* Consult Nasse's Remarks on the influence of arterial blood on the developeraent 
and functions of the human body, founded on cases of the morbus coeruleus. Rett's 
Archiv. t. x. p. 213. 




foody; the cerebral functions seem to be unaffected. The same sym- 
ptoms ensue when the serum and red particles without the fibrin are in- 


■ The injection of blood with circular corpuscules into the vessels of a 
** (in which the corpuscules are elliptic and of larger size), produces 
•o ent symptoms similar to those of the strongest poisons, and generally 
eath, which ensues, indeed, instantaneously, even when a small quan- 
1 y only of the blood has been injected; such, for example, was the 

e ect of the transfusion of some blood of the sheep into the veins of a 

while in many cases in which the blood of sheep and 



e c 

In Dieffenbach's* 

to be fatal to 

duck ; 

as injected into the vessels of cats and rabbits, these animals were re- 
Vlved for a few days. The fact of the blood of mammalia being poison- 
ous to birds is very remarkable ; it cannot be explained mechanically. 
■■^ e injection of fluids containing globules of greater diameter than 

apillary vessels produces death by obstructing the pulmonary 
ve ssels, and producing asphyxia ; but the corpuscules of the blood in 
mammalia are even smaller than those of birds. 

numerous experiments, pigeons were killed by a few drops only of 
tn e blood of mammalia. The blood of fishes is said 
mammalia as well as to birds. 

[The interesting experiments of Dr. Bischofff throw new light on 
e subject of transfusion. He confirms the statements of Prevost and 
umas, and of Dieffenbach, as to the deadly effect of the blood of 
mammalia injected into the veins of birds. In all his experiments made 
with the fresh blood of mammalia, the birds (common fowls) died with- 
in a few seconds after the performance of the transfusion, with violent 
symptoms resembling those of poisoning. But when, instead of the fresh 
unchanged blood, he injected blood from which the fibrin had been re- 
moved by stirring, and which was heated to the proper temperature, he 
was surprised to find that no symptoms were produced,-the animal ap- 
peared to suffer no inconvenience. These experiments were performed 
repeatedly, so that there could be no fallacy in the result. I was pre- 
sent when Dr. Bischoff performed them before his class at Heidelberg 
in July 1835. The deadly effect then of the blood of mammalia on 
birds is in some way connected with the fibrin of the blood. The prin- 
ciple which renders the blood of one class of animals thus injurious for 
another class, is not, Dr. Bischoff remarks, identical with the vivifying 
Principle of the blood, which might be supposed to be peculiar to each 
individual class, and deadly to others ; for the blood, when thus deprived 
of its fibrin, has still the effect of perfectly restoring the animal from 
which it was taken, although the latter be reduced by loss of blood to 
extreme syncope or apparent death: but it is an important fact, that 

* Die Transfusion des Blutes, von Dieffenbach. Berlin, 1828. 
t Miiller's Archiv. 1835. 



■ [mil 

m I 



when blood thus deprived of its fibrin is injected into the veins of 
an animal of a different class, reduced to a similar state of syncope, no 
revival takes place, — the animal dies. Hence the blood of an animal of 
a different class, even when deprived of its fibrin, although not poison- 
ous,, is not adapted for the operation of transfusion, in cases where this 
is necessary in man. 


Dr. Bischoff mentions but one experiment in which he injected the 
blood of a hen (about half an ounce), deprived of its fibrin and warmed, 
into the vessels of a dog, and in this instance no other effect was pro- 
duced on the animal than a state of exhaustion which might be the re- 
sult of his struggles during the operation. 

The experiments of Dr. Bischoff on the transfusion of different kinds 


of blood into the veins of frogs, are from the difficulty of the operation 
less satisfactory. The results, however, which he has deduced from 
them seem to be tolerably certain. The blood he used was in all cases 
deprived of its fibrin, and its effects, so far corresponded with those on 
the higher classes of vertebrata that it did not produce an immediately 
fatal result; but it nevertheless had a marked injurious effect on the 
system, and this was most violent when human blood was injected, less 
so when that of mammalia and birds was used. The blood of fishes had 
in several instances no particular effect. When the blood of crabs was 
injected, the frogs lived several days, but died eventually. The effect of 
the transfusion of the blood of man, mammalia, and birds, was always 
death, generally in a few hours, the only symptom being diminished 
activity of the circulating organs ; the heart in some cases seemed to 
be paralysed. After death there was found in almost all cases effusions 
of a reddish serum, containing the red particles of the frog mixed with 
those of the blood injected, particularly in the stomach and abdominal 


An incautious injection of air into the veins and blood of a living 
animal is almost immediately fatal by obstructing the circulation in the 
small vessels, and in the heart. Nevertheless, in Nys ten's experiments, 
very small quantities, not only of atmospheric air and oxygen, but even 
of irrespirable gases, such as nitrogen, nitrous oxide, hydrogen, carbu- 
retted hydrogen, carbonic acid, and carbonic oxide, were injected into 
the vessels without fatal consequences. Nitric oxide gas, sulphuretted 
hydrogen, ammonia, and chlorine, were the only gases which he found 
to be deadly.* 

b. Evidences of life in the blood itself. 

of the 

Professor C. H. Schultz 

has spoken of an active vital process which can be seen to be constantly 
going on between the individual molecules of the blood and the sub- 

* Nysten, Recherches de Physiol, et de Chim, Pathol. Paris, 1811. 



stance of the vessels.* When 


we sun, which produce a dazzling but very confused illumination 


< e slightest appearance of spontaneous independent motion of the 

th . dual red P articles - During the last ten years I have examined 
e circulation of the blood in the most various parts, at every oppor- 
tunity, and with different instruments; but have never, when the ob- 
ject was well illuminated, seen what Schultz describes, — I mean the 
constant assimilation, disappearance, and new formation of the globules ; 

nor have other observers 



or e successful than I have been. The observer may convince him- 

also that the motion of the red particles in the circulation is 

passive, by compressing the vessels of a limb, or the whole limb itself. 

either under these circumstances, nor at other times, do 

the glo- 

u es show any attraction or reciprocal action among themselves. 

' 10 ^ever, the direct rays of the sun are allowed to shine through 

a transparent part, the distinctness of the image is entirely lost owing to 

e refraction of light which is produced by the inequalities of the sur- 

ace, as well as by the red particles which act as so many little lenses ; 

16 obser ver no longer perceives the red particles flowing through the 

essels, but there is a general sparkling flickering motion, in which 

requently even the direction of the current is not distinguishable. 

e same deception of vision is produced, when a fluid containing 

g obules — milk, for example — is viewed while flowing over the surface 

°f a glass under the microscope, by the direct rays of the sun ; and even 

clear water flowing over the surface of ground glass has by a similar 


to the 

■will be considered in treating of 

animals, is still less admissible. The theory which ascribes 
blood a self-propelling power— a power of motion, which continues 
^nen the heart has ceased to act 
circulation in the capillaries. 

Treviranus, Mayer, and others, have regarded as an automatic 
movement that confused motion of the globules which is seen to con- 
tmue for several seconds in a drop of blood placed on a glass under 
the microscope. The fallacy of this opinion is, however, completely 

C. H. Schultz, der Lebensprocess im Blute. Berlin, 1822. 
t Meyen, Isis, 1828, 394, and the review by an anonymous writer,— Isis 1824 3 
are especially worthy of being consulted on this subject. 

Mayer, Supplemente zur Lehre vom Kreislauf. Bonn, 1827. 

[The hypothesis here alluded to is partly discussed by the author in this place • 
but the translator, to avoid repetition, has placed all the arguments together in the 
caapter on the circulation in the capillaries.] 


t . 





single contiguous 


proved by the fact, that these momentary whirling motions can be seen, 
as I have often witnessed, in drops of blood which has been long re- 
moved from the body. Thus, for example,, in a drop of frog's blood 
which has been taken from the animal twelve or twenty- four hours, and 
from which the fibrin has been removed, we can distinguish by means 
of the microscope the same motions of the red particles as in fresh 
blood ; they cannot therefore be dependent on vitality. In the blood of 
warm-blooded animals such motions may also arise from evaporation. It 
is probable, likewise, that the slight change of form which every drop of 
fluid spread on a glass plate suffers at the edges, and sometimes quickly, 
has considerable influence on these motions. I have also often remarked 
in a drop of diluted frog's blood, whether when fresh, or after it had 
been kept several hours, the fibrin having been removed, that, after the 
cessation of the first described motion, 

approach each other very slowly. This, however, is probably also 
dependent on physical causes, such as evaporation, and the attraction 
of adhesion. > 

Motions in coagulating blood. — Heidmann* has described contractions 
and dilatations which he has observed in the blood during coagulation. 
I have myself, however, been able to detect no dilatation, and no other 
contraction than the gradual imperceptible contraction of the coagulated 
fibrin. The contractions which Tourdes and Circaud described to be 
produced in the fibrin by galvanism have been proved, even by Heid- 
mann himself, not to exist, and I certainly saw nothing of the kind 
in galvanising the liquor sanguinis of the frog's blood.f 

Is the blood endowed with life ? — The question whether the blood 
be a living fluid or not, calls to mind a critical state of our science. 
Everything which evidences an action which cannot be explained by 
the laws of inorganic matter, is said to have an organic, or, what is the 
same thing, a vital property. To regard merely the solids of the body 
as living is incorrect, for there are strictly no organic solids ; in nearly all, 
water constitutes four-fifths of their weight. Although then organic 
matter generally be considered as merely u susceptible of life," and the 
organised parts as " living," yet the blood also must be regarded as 
endowed with life, for its actions cannot certainly be comprehended 
from chemical and physical laws. The semen is not merely a stimulus 
for the fructification of the egg, for it impregnates the eggs of the 
batrachia and fishes out of the body ; and the form, endowments, and 
even tendencies to disease of the father are transferred to the new 
individual: the semen, therefore, although a fluid, is evidently endowed 
with life, and is capable of imparting life to other matter. The im- 
pregnable part of the egg^ the germinal membrane, is a completely un- 
organised aggregation of animal matter, and nevertheless is animated 

* Reil*s Archiv, vi, 425. 

f See experiments related at note, p. 137. 




with the whole organising power of the future being, and is capable of 
imparting life to new matter, although soft and nearly allied to a fluid, 
■The blood also evidences organic properties ; it is attracted by living 
or gans which are acted on by vital stimuli; there subsists between the 
blood and the organised parts a reciprocal vital action, in which the 
Wood has as large a share as the organs in which it circulates. The 
fibrin of the blood effused in inflammation is at first fluid, and forms, as 
11 becomes solid, pseudo-membranes ; but this exudation, by means of 
a mutual vital action exerted between it and the organs by which 
11 is poured out, becomes organised and traversed by blood and vessels. 
The blood itself has, therefore, the properties of life, and this is the 
case with all the animal fluids except those which are the means of 
carrying out of the body the effete material, such as the urine and 
carbonic acid. The saliva and the bile exert an assimilating action on 
the food, the different organs perform the same functions with regard 
to the blood, and here there is no clearly defined limits between sub- 
stances capable of life and those endowed with it. Those substances, 
however, in which life is least evident, remain susceptible of life as long 
a s they are not chemically changed. 

c. Formation of the blood. 

The materials for the formation of the blood are the contents of the ab- 
sorbent system, namely, the transparent lymph and milky chyle, which 
convey into the thoracic duct, and thus into the blood,— the former fluid, 
those nutritive matters taken up from the intimate structure of the 
organic body; the latter, those absorbed from the intestinal canal. The 
lymph and chyle contain albumen and fibrin in solution, but these sub- 
stances are in less proportion in them than in the blood. The lymph 
has the greatest possible resemblance to the liquor sanguinis of the 
blood, which also contains lymph and albumen in solution; so that the 
liquor sanguinis may be correctly termed the lymph of the blood, while 
the blood may be regarded as lymph with red particles, or the lymph as 
blood without red particles. The chyme or digested food in the intes- 
tines contains albumen in solution, but no coagulable fibrin ; the latter sub- 
stance is formed in the absorbents, and thence is poured into the blood. It 
s a remarkable fact, which I have observed to be nearly constant, that 
in frogs kept long without food, the blood frequently loses its property of 
coagulation, and that in these cases the lymph, which usually coagu- 
lates quickly like the blood, also does not coagulate. In winter, how- 
ever, the blood of the frog often coagulates, although not completely ; 
but in all cases where their blood does not coagulate perfectly, the 
coagulation of the lymph is also not so firm. I find this to be the 


case in many frogs dug out from the ground in winter, although they 
are quite active. Lymph and chyle contain somewhat less solid matter 







■ ~» - ^ 

's * 



than the blood, and especially less fibrin ; 100 parts of chyle, according 
to Tiedemann and Gmelin, contain from 0-17 to 1*75 parts of dry 
fibrin. Chyle is less distinctly alkaline than the blood. There is a cer- 
tain quantity of uncombined fat in the chyle, which appears to become 
more intimately combined in the blood. Iron also is in a state of less inti- 
mate combination than in the blood, and can be detected, according to 
Emmert, by adding tincture of galls to chyle previously treated with 
nitric acid. [The globules of the lymph will be particularly described at 
a future page ;* we have already seen that they differ both from the 
red particles of the blood, and from the nuclei of the red particles, in 
form as well as in size, but they resemble exactly the more scanty 
globular bodies which are contained in the blood mixed with the red 

Autenrieth supposes that the chyle poured into the circulation, is con- 
verted into blood in the course of ten or twelve hours, because within 
this period the serum is frequently observed to be milky. It is proba- 
ble, however, that the change is effected still more slowly; for, as I 
have already remarked, when the coagulation of the blood is retarded 
by the addition of sub-carbonate of potash, the supernatant fluid from 
which the red particles have subsided, is often somewhat turbid and 

In what part of the system the red colouring matter or envelope of 
the red particles of the blood is produced, is quite unknown ; it is not 
present in the chyle and lymph ; a slight trace of it only being sometimes 
detectable in the thoracic duct. Respiration seems to have a share in 
its production. Hewson's hypothesis that the red colouring matter is 
formed in the spleen and in the lymph of the spleen, which is sometimes 
of a dirty red colour, is without foundation ; the spleen may be extir- 
pated from living animals without bad consequences. 

It is quite impossible to imagine the cause of the different forms of 

the red particles in the different classes of vertebrate animals. There 
are no similar elementary forms in the whole body. 

Formation of the 

In the incubated egg the sole 

material for the first formation of the blood, is the substance of the 
germ or germinal membrane, which itself grows by assimilation of the 
fluid of the egg, or the yolk. It may be distinctly observed, that the 
blood is first generated in the germinal membrane before the vessels and 
before the glands are formed, which in the adult have some influence on 
the formation of the blood. The germinal membrane, at first simple, 

a short time found to consist of an upper thinner or serous 
layer, and an under thicker or mucous layer. Around the first trace 

[The description of the lymph globules, and the comparison of them with 

the red particles of the blood were repeated here, but have been omitted by the 




of the embryo, which is visible in the centre of the germinal membrane, 
a transparent space or area pellucida is formed, while the part of the 
germinal membrane nearer the circumference remains opaque, and 
this opaque portion again is soon divided by a line of separation into 
a *i outer and inner space; these changes take place in the ovum of 
hirds, in from sixteen to twenty hours.* That division of the opaque 
portion of the germinal membrane, which is immediately within the 
hne of separation above mentioned, and which surrounds the innermost 
portion or transparent afea, is called the area vasculosa, because within 
*t the blood and vessels are formed. As far as the area vasculosa ex- 
tends, there is found between the two layers of the germinal membrane 
^ granular deposit which soon becomes arranged in granular close 
*slets separated by transparent interspaces, in which first a yellowish, 
afterwards a red fluid, — the blood,— collects. The presence of blood is 
" r st distinctly observable in the periphery of the area vasculosa. 

The red particles of the blood in the embryo of the bird for the first 
ew days after its appearance in the germinal membrane, are, according 
Prevost and Dumas, round, and do not begin to assume the elliptic 
form before the sixth day ; on the ninth day they are all elliptic, f new- 
son, Schmidt,^ and Doellinger have made a similar observation. The 
same fact has been observed also by Baumgartner § in reptiles and fishes, 
and by E. H. Weber|| in the tadpole. 

Baumgartner describes the formation of the red particles of the blood 
in the following manner : — The corpuscules, he says, are at first not 
elliptic or flattened, but globules composed of a number of smaller 
globules similar to those of the yolk of the egg ; they gradually become 
transparent, and at the same time this granular state disappears ; the 
transparent ring is then developed, and the nucleus formed. The elliptic 
form is gradually assumed. Weber also describes the corpuscules of 
the blood in very young tadpoles to be composed of several smaller 
granules. Baumgartner supposes that the smaller granules here mention- 
ed are derived from the yolk. Another mode in which Doellinger^ and 
Baumgartner imagine the red particles of the blood to be formed, both 
young and adult animals, is the separation of particles from the 

!t is evident that in the embryo the blood is formed from the 

substance of the germinal membrane, which assimilates to itself the 

uids of the egg, and that no particular organ is then required ; for 

*t that period no organs, such as intestinal canal, liver, spleen, or lungs, 

This fact teaches us that we must not expect to discover the 

Y/ Baer ; de ovi mammalium genesi. f Froriep's Notiz. 175. 

t Uber die Blutkorner. Wiirzburg, 1822. 

§ Uber die Nerven und das Blut. Freiburg, 1830. || Loc. cit. iv. 478. 

% Denkschr. der Akad. zu Munchen, vii. 169. 











indeed it is very probable that the chyle is converted into blood, in 
the adult also under the influence of the same general vital conditions 
which are in action in the incubated egg. 

Action of respiration in the production of blood. — Respiration seems to 
have an essential share in the process, inasmuch as even in the incu- 
bated egg the influence of atmospheric air, and in aquatic animals that 
of water containing air, seems to be quite necessary for the develope- 
ment of the embryo, and the air suffers the changes which ordinarily 
take place in respiration. From an important observation of Von 
Baer * it would seem probable that in the original formation of the 
blood in the germinal membrane in mammalia, the respiratory change 
is by no means essential ; for Baer has seen the ovum of the bitch, at 
a period when the area vasculosa of the germinal membrane already 
contained blood and vessels, quite free in the cavity of the uterus, and 
without any connection with it, by which the function of respiration 
could be supplied : Burdach supposes that under these circumstances 
the plug of mucus closing the uteri of pregnant mammalia allows the 
passage of air to the ovum. The state, in which there is no vascular 
connection with the uterus, is indeed a permanent condition of the 
ovum of the marsupial animals.f In the foetus of mammalia there is, 
however, even at a later period, no distinct difference between arterial 
and venous bloody and the want of respiration is supplied by a process 
of another kind, which is maintained by means of the union of the 
ovum with the uterus, but of which the nature is unknown. 

Perhaps respiration is not immediately necessary to the formation of 
the colouring matter. The necessity of respiration is indeed supported 




when obtained pure) has a red tinge in the thoracic duct, cannot at pre- 
sent be adduced as a proof that the formation of the colouring matter 
commences in the lymphatic vessels, for it is very possible that a few 
red particles may regurgitate into the ductus thoracicus from the venous 
trunk and mix with the chyle. I cannot confirm the observation of 
Goeze, which Treviranus adduces, namely, that the blood in the 

hyberaating frog in its torpid state in winter is whitish ; although 
throughout the winter season, when the weather allows of digging, I 
obtain frogs which have been dug from the earth, although certainly 
not torpid. 

That the blood during respiration undergoes a change necessary to 

* Loc. citat. ^. o W en. Philos. Transact. 1834, p. 2. 

$ See the chapter on the respiration of the ova of animals. 

J 4 



the preservation of Jife, is proved by death occurring whenever this 
function is interrupted. The nature of the change, however, — the 
influence which respiration has on the formation of the blood,— cannot 
be accurately determined ; we have no means of ascertaining whether 
the blood would acquire its red colour and the other properties con- 
nected with this colour, — whether any red particles would be develop- 
ed, if respiration was not performed, A very small portion only of the 


changes which take place in the passage of the blood through the lungs 
is recognisable, and that is the change of the dark red colour of the 
blood to a bright red, which during its passage through the capillary 
vessels of the body generally is reconverted to a dark red. But 
unfortunately even here it is the change of colour only that we are ac- 
quainted with, and not the material change which accompanies it.* 

It is still uncertain in what part of the body the carbonic acid which 
is expired during respiration, is formed. The changes produced in the 
air by respiration, as far as regards the bulk of the component gases, 
can be as well explained on the supposition that the carbonic acid 
is formed in the lungs by the direct union of the carbon of the blood 
with the oxygen of the air, as on the theory that the carbonic acid 
is formed in the course of the systemic circulation, and especially in 
the capillaries. But it is at least probable that a part of the oxygen 


of the air is absorbed by the blood ; and as no oxygen can be again 
separated artificially from arterial blood, it appears to enter into a state 
of chemical combination with it. The proportion of nitrogen in the 
air respired is not essentially altered. 

The absorption of oxygen and the separation of a portion of carbon, 
therefore, are the causes to which arterial blood owes its property of 
being the sole stimulus of living structures. Venous blood which has 
not undergone this change has a poisonous action on the organs of the 
body, particularly on the nervous system, and annihilates their irrita- 
bility ; its action being similar to that of carbonic acid, sulphuretted 
hydrogen, carburetted hydrogen, and some other gases, by which the 
irritability of the organs of the body is destroyed, and by most of which 
the arterial blood is darkened in colour. Cuvier* supposes, indeed, that 
the arterial quality of the blood is diminished even during its course 
from the heart to the capillary vessels, by reason of some change of 
composition which it undergoes, and thus explains the inferior degree 
of vitality possessed by parts distant from the heart. 

Another difficulty which we are quite unable to solve is, whether the 
venous blood is incapable of supporting life from having lost some- 
thing which arterial blood possesses, or from having suffered some 


See the comparison of arterial and venous blood in the chapter on the changes 


which the blood undergoes in respiration, 
f Verg. Anat. p. 147. Anatomie compare. 








noxious change in the Combination of its elements, the natural combina- 
tion being in the latter case again restored by respiration and the separa- 
tion of the carbonic acid. It is very remarkable, however, that the 
venous blood of the embryo of mammalia, although strictly speaking it 
does not respire, has not this injurious, as it were a suffocating, influence 
on life, whether it be that this injurious quality cannot be developed until 
respiration, and consequently the reciprocal action of true arterial blood 
with the tissues take place, or that the want of respiration is supplied 
by the connection of the embryo with the mother. 

Since the blood is constantly throwing off carbon in the process of 
respiration, it might be thought that the relative proportion of nitro- 
gen in the body ought to increase. Cuvier believed that animal matters 
are in this way more highly animalised, because the characteristic 
element of animal substances is the nitrogen they contain. If this were 
correct, the flesh of a living animal must contain more nitrogen than 
the flesh of animals from which it is nourished, which involves a con- 
tradiction. Respiration viewed in this way would be no advantage to 
carnivora, and would be more necessary to herbivora, because their food 
contains less nitrogen. But the relative increase in the quantity of 
nitrogen in the animal body which the separation of carbon in respira- 
tion would produce is generally not permanent, for an excess of nitrogen 
is being constantly excreted from the body in the urea and uric acid of 
the urine, which contain more nitrogen than any animal substance. 

The influence of the spleen, suprarenal capsules, and of the thyroid and 
thymus glands on the formation of the blood, is not at all understood.* 

Influence of the excretions on the formation of 

The separa- 


tion from the blood of certain matters which are afterwards excreted 
from the animal economy, has a great share in preserving the normal 
composition of the circulating fluid. Some of the matters here al- 
luded to have been introduced from without, and are either in 
themselves useless, or are in too abundant quantity. Of these, water 
is got rid of by exhalation from the lungs and skin, and by the urine ; 
the mineral substances are expelled chiefly by the urine ; and matters 
containing an excess of carbon, nitrogen, oxygen, or hydrogen, 
eliminated in various ways :— the carbon by the lungs ; combinations 
containing much carbon and hydrogen by the liver ; and those in which 
the nitrogen is abundant by the kidneys. Other of the substances that 
disturb the normal constitution of the blood are newly formed in the 
body, and, being taken up into the blood, must be subsequently excreted 
from it. Such seem to be several of the matters contained in the urine. 
This shows how the proper composition of the blood when once esta- 
blished is maintained. 

Another question is, whether the separation of certain ingredients 
from the new nutritive matter which the blood derives from the food, 

* See Book II. section 2, 




contributes essentially to the original production of the normal compo- 
sition of the blood? The lithic acid of the urine, — a product contain- 

• - 

mg a large quantity of nitrogen, — is derived without doubt, at least in 
part, from this source ; for its quantity in the urine is increased by 
merely taking animal food, or substances containing a large proportion 
of nitrogen ; and in the urine of herbivorous mammalia it does not exist, 
but is replaced by hippuric acid (urino-benzoic acid). It is not yet 
known whether lithic acid exists in the blood, and is merely separated 
from it by the kidneys, or whether it is first formed in the urinary or- 
gans ; although under certain circumstances it is deposited from the 
blood in different parts, for instance, in the neighbourhood of joints, 
forming gouty concretions. 

Urea is not formed originally by the organs which excrete it, — name- 
ly? the kidneys ; for Prevost and Dumas have shown that it can be 
detected in the blood when the kidneys have been extirpated, so that 
the reason why this substance is not found in healthy blood, is that it 
*s separated from it by the kidneys as fast as it is formed. On the third 
day after the extirpation of both kidneys, the following symptoms arise ; 
brown, copious, very fluid evacuations from the intestines, and vomiting, 
fever, with the temperature raised to 110° Fahr., sometimes, however, 
depressed to 92° Fahr. ; the pulse becomes small, and quick, and rises to 
200 beats in a minute, the breathing frequent and short, and at last 
laboured. Death ensues between the fifth and the ninth day. In 
Mayer's* experiments it took place in from ten to thirty hours, being pre- 
ceded by tremblings and convulsions. Effusion of clear serum is found 
in the cavities of the brain, the bronchi are full of mucus, the liver 
inflamed, the intestinal canal full of fluid feces coloured with bile, the 
urinary bladder much contracted. The blood of the animals experi- 
mented upon — dogs, cats, and rabbits — was more watery than natural, 
and contained urea, which was extracted by means of alcohol. Five 
ounces of the blood of a dog, which lived two days after removal of 
the kidneys, afforded more than twenty grains of urea ; two ounces of 
cat's blood yielded ten grains.f Vauquelin and SegalasJ have con- 
firmed this discovery. In their experiments the blood was evaporated 
to dryness, the residue washed, and the water evaporated ; the mass 
left was then treated with alcohol, and this again evaporated. The 
water, however, must be evaporated at a low temperature, under the 
vacuum of the air-pump, with sulphuric acid. They thus obtained from 
the blood of a dog, whose veins were opened sixty hours after the ope- 
ration, xi^th part of urea. Urea and uric acid contain more nitrogen 
than any other known organic substance. || 

* Tiedemann in Treviranus, Zeitschrift fur Physiol. 2, 2, 278. 

t Biblioth. Univers. xviii. 208. Meckel's Archiv. viii. 325. 

t Magendie's Journal de Physiol, ii. 354. Meckel's Archiv. viii. 229. 

|| See the Section on Secretion, chapter 8. 





The first conclusion might 


The presence of urea in the blood may be accounted for in two ways. 
First, it may be supposed to be formed as a useless compound of the 
superfluous elements in the conversion of the food into the essential 
components of the blood ; or, secondly, it may be conceived that it is 
an effete product of the change of material that is constantly taking 
place in the organised parts of the body, 
be suggested by the circumstance that Tiedemann and Gmelin, in one 


of their experiments on chyle, observed that the muriate of soda mixed 
with the osmazome of the chyle crystallised into octahedrons instead of 
cubes, while in other cases it took the cubic form ; for urea is known to 
have the power of altering the crystallisation of this salt to the octa- 
hedric form,* But there are other facts which render this conclusion 
improbable. Urea is formed in a certain quantity by reptiles, which 
have fasted even for months ; and in the urine of a madman who had 
fasted eighteen days, Lassaigne found all the components of healthy 
urine, f Moreover, in the urine of herbivorous animals, (whose food 
contains very little nitrogen,) there is a considerable proportion of sub- 
stances containing nitrogen, such as urea. There is certainly no doubt 
but that the kidneys separate from the blood the useless matter derived 
from the food ; for the urine varies in composition, according as the food 
varies; for instance, it contains more uric acid when the food consists of 
animal matter. 

trogen, the excrements contain much less white matter, or uric acid, 
than when they are fed upon white of egg. j: In the composition of the 
urine of herbivorous and carnivorous animals, there is a difference cor- 
responding with the difference of their food ; the urine in the former 


animals contains hippuric acid, instead of uric acid, and is alkaline in- 
stead of acid: the urine of birds generally contains superlithate of am- 
monia ; but the urine of birds feeding on vegetables contains no urea. 
There is, however, also no doubt but that certain components of the 
urine are also formed from effete elements of the blood, or of the solids 
of the body. Since then it appears certain that the products of the 
urine are not merely separated from the blood to give the latter its 
proper elementary composition, we may suppose that the urea is pro- 
duced by component parts, either of the blood or of the tissues of the 
body becoming unfit for further use, or that during the reciprocal action 
of the arterial blood and the organs on each other— an action so neces- 
sary to life — certain components, either of the blood or of the tissues 
of the organs, are converted into useless combinations, being in fact 
chemically changed. It is, however, improbable that the latter is the 
mode of their formation, from the circumstance that lithic acid at least 

* Tiedemann und Gmelin, Versuche liber die Verdauung, ii. 91. 
t Journ. de Chim. Med. 272. - 

% Tiedemann und GmeJiri, die Verdauung, ii, 233. 

In birds which feed on substances containing no ni- 




is formed in the embryo. It is found in the allantois not only of birds, 
but also of mammalia ; and the foetus of mammalia, while in the uterus 
of the mother, does not respire in the proper sense of the word, and 
therefore has no arterial blood, although the want of respiration is sup- 
plied by the connection of the foetus with the mother. Besides, the 
formation of the substances of which we are here speaking commences 
extremely early in the embryo. The kidneys, it is true, are not formed 
in the incubated egg of the bird till about the sixth day ; and in the 
embryo of fishes and salamanders, according to my researches, not 
till the state of larva has succeeded that of the embryo; but at a re- 
markably early period there are other organs in their place, namely, 
the Wolffian bodies, first accurately described by Rathke and myself. 
These organs consist of caeca communicating with an excretory duct ; 
in the embryo of birds they exist as early as the third day ; and, 
according to my observations, form from the blood a true secretion of 
a yellow colour, similar to the urine of birds ; while the allantois, as 
Jacobson* discovered, contains at the same time, namely, a very few 
days after the commencement of incubation, lithic acid. The 
bodies are found in the embryo of all vertebrata with the exception of 
fishes : they disappear in some animals earlier than in others ; in the 
batrachian reptiles not until they have acquired the state of larva ; 
in birds at the time of hatching, or even later ; in the mammalia very 
early, and earliest of all in man.f 

By means of the skin the blood throws off lactic acid, lactate of ammo- 
nia, muriate of ammonia, and carbonic acid. Lactic acid, which also 
passes off by the urine, is, according to Berzelius, an universal product of 
the spontaneous decomposition of animal matters within the living body; 

it is formed in great quantity in the muscles, is neutralised by the blood 
and its alkali, and separated in the kidneys with acid urine. 

The important office which the bile performs in the assimilation of ani- 
mal matters in the intestines is not better understood. The fact of its 
being poured, both in vertebrata and in mollusca, into that part of the 
canal where the formation of the chyme is completed, proves that it is 
not excrementitial merely ; besides its most abundant component, pi- 
cromel, has evidently some connection with the assimilation of the chyme, 
for it is not found in the faeces. Some, however, of the components of 
the bile are certainly excrementitious matters thrown off from the blood ; 
and these are essential components of the faecal matter. Such are the 
resin of the bile, cholesterine, and the colouring matter of the bile, of which 
no traces are found in the chyle. The liver, therefore, frees the blood 
from an excess of matters containing carbon and hydrogen, and from 
fatty matter, while the kidneys remove from it the superabundance of 


* Meckel's Archiv. viii. 322. 

t J. Mueller Bildungsgeschichte de Genitalien. Dusseldorf, 1830. 






those materials which contain a large proportion of nitrogen. The co 
louring matter of the bile, which is also excrementitious, contains nitrogen 
The lungs and liver are so far analogous, inasmuch as both separate from 
the blood substances containing a large proportion of carbon In the 
former case, however, it isalready combined with oxygen; in the latter case 
it is still in the oxidisable state. Earlier physiologists, and more recently 
Antenneth, and particularly Tiedemann and Gmelin, have directed 
attention to a certain vicarious action in the functions of the lungs and 
liver. Although it does not appear that the size of the liver is throughout 
the animal kingdom in the inverse ratio of the size of the respiratory or- 
gans, yet pathological observations are certainly in favour of the existence 
of such a relation. 


The excretory action of the liver is exerted also under circumstances 
in which digestion is not carried on. For although the liquor amnios is 
swallowed by the foetus, it is only during the latter period of gestation • 
while the liver is developed and secretes at a very early stage of fcetal 
life, and the bile, although less bitter and less coloured at that period 
contains, according to Lassaigne,* a green resinous matter and a yellow 
colouring matter, but no picromel. In fact, it is the excrementitious 
matter of the bile of the foetus, which collects together with intestinal 
mucus m the lower part of the canal, forming the meconium. It appears 
from the experiments of Tiedemann and Gmelin that the secretion of bile 
is carried on in the same way in hybernating animals during their state 
of torpor. These inquirers also state, that Cuvier has observed in many 
molluscous animals that a small portion only of the bile is poured into 
the upper part of the intestinal canal ; while the rest is evacuated by 
a separate duct either into the caecum, as in the aplysia, or near the 
anus, as m the doris and tethys. It is, however, at present very doubtful 
whether the secretion which in the last two animals is poured out near 
the anus, is bile, and it certainly cannot be the greatest part it. I have 
examined several large examples of the doris, and found the excretory 

r rV^ ^ UViGr i 1 ^ d ! SC0Vered ' Jt a PP e ^> ^wever, to arise, not, 
like the bile ducts, from the clustered vesicles of the liver- but by nu 

merous branches, some of which run between the lobes of the liver from 
a reticular tissue which is extended over its whole surface, while one 
large trunk comes from the interior. To me it appeared that two kinds 
of fluids are here separated from the blood, which is distributed through 
the mass of the liver, there being perhaps a special apparatus for the for- 
mation of each secretion. In its point of termination, this duct discovered 
by Cuvier , s analogous to the excretory duct of the saccus calcareus of 
snails, but its origin is certainly very different. 

The frequency of diseases of the liver and the intestinal canal in tro- 
pical climates and hot seasons, and of affections of the liver and abdomi- 


Ann. de Chim. et de Phys. xvii. 304. 



nal organs in damp marshy air, is still unexplained. Could it be ascer- 
tained that these circumstances in some way impede the circulation and 
cause congestions, it would be easy to conceive why the liver and intes- 
tinal canal should suffer most in those cases; for the circulation in these 
viscera must be doubly impeded, the blood of the intestinal veins and 
porta having to circulate through a second capillary system, namely, 
that of the liver, before it reaches the general circulation. Tiedemann 
and Gmelin maintain that the increased secretion of bile in tropical 
climates is required to compensate for the diminished purification of the 
blood in the lungs ; many persons supposing that the function of the 
latter organs is rendered inefficient on account of the rarification of the 
air by the heat. Stevens* thinks this assumption incorrect; for in the 
West Indies, he says, the inhabitants of the smallest islands, which are 
the driest and hottest, but in which there are no stagnant waters, are 
free from diseases of the liver and increased secretion of bile, and these 
diseases are prevalent in hot climates only where there is a marshy at- 
biosphere (malaria). 


Of the Circulation of the Blood and of the Vascular System. 




Peculiar chemical changes of an organic nature are effected in the 
blood in special organs of the body. All parts of the system, however, 
require a supply of blood which has undergone these changes, and hence 
the circulation of this fluid is indispensable. 

The circulation of the blood was discovered in the higher animals by 
Harvey in 1619. It has since been found to have a much more extended 
existence ; and although it cannot be asserted to be a universal character 
of all animals, yet at every advance of observation new traces of vessels 
are discovered in the most simple beings. Ehrenberg has described them 
in the rototoria, and even microscopic minuteness does not appear to 
preclude the existence of this complex structure. The following are the 
more important facts relative to the different forms of the vascular system 

in the animal series. 

Circular currents in the lower animals. — In several of the lowest tribes 
of animals there are circular currents similar to those in the chara. Thus 

* Observations on the Healthy and Diseased Properties of the Blood, London, 1832, 

p. 59. 

f [The translator has made considerable alteration in the arrangement of the con- 
tents of this chapter.] 



r gt 

Nordmann has observed in the envelope of the alcyonella diaphana small 
isolated circulations, and similar currents have been described by Carus 
between the ambulacra of the sea urchin ; the ascending and descending 
motions in the stem of the sertularia observed by Meyen* and Lister are 
of the same kind. Lister asserts that they are connected with the sto- 
mach, and change their direction from time to time. Ehre 
observed circular currents of granules in the medusa and in the retractile 
fibres on the dorsal aspect of the asterias. These phenomena seem to 
be wholly independent of the action of a heart, but they have not hitherto 
been sufficiently investigated, to lead to any important conclusions with 
reference to the circulation in the higher animals. It is possible that they 
depend on the motion of cilia within the vessels. 


Circulation in acalepha and entozoa. — In the medusa tribe the fluids 
are distributed through the body by means of vessel-like ramifications of 
the digestive sacs. In the planaria and the trematoda the intestine is rami- 
fied like a vessel. But, in addition to this, these animals possess an inde- 
pendent vascular system, which however in the distoma and diplostoma 
appears to have an external opening at the posterior part of the animal.^ 
In thediplozoa,whichalsobelongto the order trematoda,— intestinal worms 
provided with suckers,— Nordmann has described two vessels on each side 
in which the blood moves in opposite directions. It appears from the 
statements of Ehrenberg and Von Nordmann that in these animals,— the 
trematoda, — the motion of the fluid is not dependent on contractions of 
the vessels themselves ; it may possibly be effected simply by the con- 
tractions of the entire body, if the vessels are furnished with valves 
arranged all in a certain direction. 

In the lowest animals of which the circulation has been accurately ob- 
served, as in the planaria, echinodermata, and leech tribe, the motion of 
the blood is effected by one, two, or more contractile vessels. These 
vascular trunks are however neither arteries nor veins, but are in part 
contractile hearts, which force the blood into anastomosing branches. 

Holothuria. — The vascular system discovered by Tiedemann in the 
holothuria seems to be of this nature ; it is situated in common on the 
intestine and on the respiratory organ, and is independent of the system 
of water tubes with which the skin of this animal is provided for the 
erection of the tentacula.|| 

In the annelides there is a progressive contraction of the vascular 
trunks, advancing regularly in one direction, and thus, 
Duges, driving the blood in a continued circle in the larger vessels; 
while at the same time the circulating fluid is thrown alternately from 
side to side through the transverse anastomosing branches, one trunk 

* Nov. Act. Nat. Cur. vol. xvi. Suppl. 

f M uller's Archiv. 1 834, 571. 

X Nordmann, Micrograph. Beitrage, 1832, i. pp. 39. 98. 

|| Tiedemann, Anatomie der Rohrenholothurie, &c. 





• * 


being filled while the other contracts, as is seen in the hirudo vulgaris.* 
When the principal trunks lie at the sides, as in the hirudo family, the 
direction of the circulation is horizontal ; when they are situated above 
and below, as in the lumbrici, arenicolae, and naides, it is vertical. 
From my own observation, I thought that in the hirudo vulgaris both the 
lateral vessels alternately emptied themselves from behind forwards. 
Duges, however, maintains that the motion is progressive in a continuous 
circle. The respiratory organs of the annelides, whether they be bran- 
chial tufts as in the arenicolae or sandworms, or pulmonary vesicles, re- 
ceive their blood, like the other organs of the body, from branches of the 
main vessels. In the nereides, Professor R. Wagner has described two 
longitudinal trunks; one on the dorsal aspect, which pulsates and impels 
the blood from behind forwards; the other on the abdominal aspect lying 
upon the nervous cord under the intestines ; the latter does not pulsate 


or contract: in addition to these Fig.l.% 

there are transverse vessels, superior * ; . f 

and inferior, corresponding to the 
ri ngs of the body; of these the infe- 
rior, which arise from the abdominal 
vessel and pass to the feet or bran- 
chiae, pulsate beautifully; the superior 
branches, which commence in the 
branchiae and terminate in the dorsal 
vessel, do not pulsate. 

Insects. — In animals in which there 
is but one contractile vessel, the cir- 
culation is simple but perfect ; the 
fluctuating motion of the blood from 


side to side does not exist, and there 

are distinct arterial and venous cur- 
rents. Such is the circulation which 

Carus f has discovered in insects (fig. 
I.): the blood flows in a simple circle, 
being impelled forwards by the dor- 
sal vessel; it returns in the opposite 

direction through the body, and again 

enters the dorsal vessel. 

* J. Mueller, Meckel's Archiv. 1828 ; and my observations on the Arenicola in the 
4th vol. of Burdach's Physiol. On the subject of the annelides generally, consult Duges, 

Ann. des sc. nat. t. xv. 

+ Entdeckunff eines Blutkreislauf, &c. Leipzic, 1827. Nov. act. nat. cur. t. xv. p. 2. 

1 . Dorsal vessel ; 2. 


simple loops to the feet ; 3. simple arterial and venous currents of the antennae ; 4. anas- 
tomosing vessels in the wings ; 5. simple currents in the caudal appendages, arising from 
and returning into the lateral venous currents (6), which brings back the blood to 
the dorsal vessel : 8. and 9 are the two lateral venous currents described by Wagner ; 




. - * 

I J 






Fig. 2 + 

I !) H 


The currents are very simple and do not ramify ; the feet, for example, 
have each two currents running in opposite directions, the arterial being 
reflected uninterruptedly into the venous, forming a loop. It is at present 
unknown whether the internal organs of insects receive any vascular 
currents. As early as 1824, however, I discovered and described a con- 
nection between the oviducts and the dorsal vessel of many insects.' 
Wagner also has since observed these connections, but agrees with Carus, 
Treviranus, and Burmeister, in considering them not to be blood-vessels. 
Whatever they may be, their existence is indubitable ; in two insects how- 
ever I have not succeeded in finding them. Wagner has added new 
facts to Carus's discovery of a visible circulation in insects; he has seen 
the particles of the blood flowing in two venous currents (fig. i. 8, 9) at 
the sides of the intestine and dorsal vessel, probably in canals without 
membranous parietes, and at the same time he has seen particles of the 
blood from these currents enter the dorsal vessel through lateral clefts. 
Strauss had previously described these lateral 
clefts at the divisions of the dorsal vessel : he 
says, that in the cockchafFer — melolontha vul- 
garis, — this vessel consists of eight chambers 
which communicate by two-lipped valves (fig. 
i. 10, 11) directed forwards, so as to allow the 
blood to pass from behind forwards.! 

Arachnida and Crustacea. — The circula- 
tion in the arachnida and the lower Crustacea, 

such as the aselli and daphnige, according to 

Zenker and Gruithuisen, is nearly as simple 

as in insects. There is no distinct pulmonary 

circulation ; but as in the arachnida with pul- 
monary sacs, a part of the blood is aerated in 

the respiratory organs in its course through 

the general circulation. In the arachnida, 

with tracheal organs of respiration as well as 

in insects, the blood is aerated by the tracheae 

mify most minutely in all parts of 

the body. In the higher Crustacea there is 

either a long tubular heart as in the squillae 

and allied genera, or a short wide one as in 

the decapoda. (Fig. 2.) 

10. is the posterior, and 1 1. the anterior of the valves discovered by Strauss ; a bristle i 

which n 

passed through the cleft between them ; 12. a bristle passed through another of the 
lateral clefts, from which the lower valve has been removed.] 

* Nov. act. nat. t. xii. 2. Compare Wagner's observations in the Isis, 1832 320. 

t Strauss, Considerations g£n6rales sur l'anatomie des animaux articul&s, & c Paris 
1829. . ' 

$ [Circulation in the lobster copied from the diagram given by Dr. Allen Thomson 
in his excellent paper on the circulation, in the Cyclopaedia of Anatomy.— 1. Heart • 2. 




The blood is collected from the body by veins, from which it is carried 
into the branchiae, returning from these to the heart, which again distri- 
butes it to the body. This course of the blood was discovered by M.M. 
Edwards and Audouin, and while at Paris I satisfied myself of its exist- 
ence by injecting a lobster. I agree with Meckel that Strauss is incorrect 
*n considering the membranous covering of the heart of these animals 
to be an auricle.* 

Mollusca. — The circulation in the mollusca is similar to that in the 
Crustacea. In the naked acephala or tunicata, — as the ascidia and salpa, 

the veins from the branchiae enter the ventricle immediately. In the 
conchifera, as well as in most gasteropoda, the blood is first collected in an 
auricle, (in the conchifera there are two auricles,,) and thence passes to 
the ventricle. 

Fig. 34 


In the majority of the mollusca all the venous blood circulates through 
the branchiae before reaching the heart, but in the conchifera (fig. 3) 

Bojanusf says, that, after passing through the hollow organ provided 
with an excretory duct, — which he considers to be a lung, later anatomists 
to be a kidney, — it is chiefly distributed to the branchiae, while a portion 

systemic veins which convey the venous blood to the sinus (3.) at the base of the 
branchiae ; 4. branchial arteries arising from the sinus ; 5. branchial veins by which the 
aerated blood is carried to the heart : 6. the systemic arteries ; 7. depression on the sur- 
face of the heart. There are two such depressions, one on each side. Lund and Strauss 
suppose that they are openings through which blood enters the heart from the cavity 
°f the pericardium or auricle. Mr. Owen also believes that they are openings closed 

by valves.] ^^fl 

* See Ann. d. sc. nat 1827, tab. 24—32. 

t Isis, 1819. 


[Diagram of circulation in the fresh-water muscle, adapted from the drawings of 
^ojanus. — 1. Ventricle ; 2. systemic arteries ; 3. systemic veins, — 14. is the large artery, 
and 15. the vein, which run near the margin of the mantle. The veins carry the blood 
in part directly to the organ (4), which is called the kidney, and in part to a venous sinus 
on the superior surface of the organ, to whiclrnt is afterwards distributed ; 5. veins by 
which a portion of the blood is returned from the kidney immediately to the auricle, 
while the rest is poured into the sinus (6), from which the branchial arteries (7) arise; 
8. branchial veins ; 9. auricle. In the smaller figure are seen the position of the two 
auricles (11) with relation to the ventricle (10), and the course of the intestine (13) 
through the ventricle ; 12. is the principal arterial stem to the anterior part of the body.] 




reaches the auricle without entering 
the respiratory organs. Treviranus* 
again says, that a portion of the blood 
returning from the branchiae in the 
bivalves circulates through the spon- 
gy organ before it gains the heart, 
just as in gasteropoda (limax and 
helix) the blood from the lungs is 
in part distributed to the organ which 
secretes the lithic acid (saccus cal- 
careus), and is then collected again 
to be sent to the auricle. 

Cephalopoda. — In the sepia (fig. 4) 
there are three separate ventricles ; 

the systemic ventricle or heart gives 
off the aorta, which distributes the 
blood to the body, from which it is 

brought by veins to the two lateral 


branchial hearts; by these it is sent 
to the branchiae, and by the branchial 
veins is returned to the systemic heart. 
In fishes (fig. 5) there is but one 
auricle and one ventricle, the venous 

* Erschein. u. Gesetze des organ. Lebens, 
i. p. 227. 

\ [Circulation in the sepia officinalis or 
cuttle-fish, after Hunter. Catalogue of Mus. 
of Coll. of Surgeons, vol. ii. — 1. The syste- 


mic ventricle ; 2. the systemic arteries ; 3. 
vena cava, with its spongy cellular covering ; 
4, 4. the divisions of the cava going to the 
branchial ventricles (6, 6), which likewise 
receive the blood from the visceral veins (5, 
5), and from the great veins of the mantle, 
of which 10 is one, the others are those 
which are seen running up by the side of 
the branchia (8); 7. branchial artery; 9, 

9. branchial veins.] 

% [Diagram of the circulation in the skate, 
raia batis. — 1. The auricle ; 2. the ventri- 
cle ; 3. the bulbus arteriosus ; 4. the bran- 
chial arteries ; 5. the branchial veins ; 6. 
the aorta \ 7* an artery given off by a bran- 
chial vein to the head (there are two or three 
such arteries on each side). The venous 
system commences by the single caudal vein 
(7*), which divides into two branches (9, 9), 
one going to the posterior surface of each 
kidney (11), to which it is distributed after 

Fig. 4.f 

Fig. 54 


^HF r 




Fig. 6. 


blood from the body generally being collected in the auricle and thence 
transmitted to the ventricle. From the ventricle it is impelled into the 
contractile bulbus arteriosus, which gives off the arteries for the bran- 
chiae, generally four on each side ; from the branchia? the blood is re- 
turned by the same number of branchial veins which unite to form the 
aorta, by the branches of which it is distributed to the body. 

[In reptiles (jig. 6) there are two auricles and one ventricle imnprfpptW 
divided into two cavities. The ve- 
nous blood brought from the body to 
the right auricle is partially mixed in 

the ventricle with arterialised blood, 
which is received from the lungs by 
the left auricle, and poured into the 
ventricle: from the right compart- 
ment of the ventricle the left aortic 
trunk and the left pulmonary artery 
generally arise ; from the left cavity 
the right aortic trunk and generally 
the right pulmonary artery; it is from 
the right aortic trunk that the arte- 
r |es of the head and upper extremi- 
ties arise, and these parts, as in the 
foetus of mammalia and birds, receive 
a larger proportion of arterial blood : 
e two arterial trunks unite poste- 
riorly to form the descending aorta. 



description has been recently published by Dr. BischofF of Heidelberg,f 
the septum between the ventricular cavities is complete, but there is a 
communication between the two aortic trunks immediately above their 

receiving veins from the muscles of the back. The two venae ( 10) cavae commence by a 
series of loops or arches, receive the renal veins (which are seen on the left side running 
between the lobes of the kidney), and afterwards the veins of the epididymis and vas de- 
epens, and then, running up behind the testes (13), unite with the large sinuses (14) 
which Heat the inner border of these organs. The sinuses mentioned communicate 
y ery freely with each other. At the point where the cava on each side pierces the 
laphragm it is joined by the brachial and jugular veins, and by the hepatic veins (15), 
°f which there are three communicating by a cross branch. Within the pericardium 
he venae cavae unite, forming a transverse tube, from which there is one opening into 
the auricle.] 

* [Heart of turtle, after Martin St. Ange. — 1. Left auricle ; 2, 2. the pulmonary 
y eins ; 3. the right auricle ; 4, 4. systemic veins ; 5. the ventricle ; the common trunk 
(6) of the pulmonary arteries, and the left aortic trunk, arise from the right side of the 
heart ; the trunk (10), which gives off the right aortic trunk (12) and the great artery 
(11) of the head, arises from the left side of the heart ; 13. the aorta.] 

t In Mdller's Archiv. for 1836. 



i i 




Fig. 7.f 

origin, by means of an opening through 
which, during the diastole of the ven- 
tricles, blood might pass from one 
aortic trunk to the other, but not dur- 
ing the systole, it being then closed 

by the valves of the aortic orifices.] 
Amphibia. — Intermediate in the 
chain of animals between fishes and 
reptiles is the class of amphibia or ba- 
trachian reptiles, of great interest in 
a physiological point of view on ac- 
count of the metamorphosis of the 
branchial into the pulmonary circu- 
lation which is observed in them. All 
the amphibia have two auricles,* the 
separation between which is not vi- 
sible externally, and one ventricle; 
they have two occipital condyles, no 
cochlea in the ear, no fenestra rotunda, no penis, no true ribs. All the 
true reptiles (saurians, chelonians, and ophidians) have two auricles dis- 
tinctly separate even on the exterior, one ventricle, one occipital condyle, 
a cochlea and fenestra rotunda, true ribs, a distinct penis, and they under- 
go no metamorphosis. All the amphibia appear to have branchiae in the 
early stage of their existence, but all except the proteidea lose them at 
a later period. The distinction between the two classes — reptiles and 



* [The existence of two auricles in the perenni -branchiate amphibia was discovered 
by Mr. Owen, (See Transactions of the Zoological Society for 1834), and a year later 
by Prof . Mayer of Bonn. See his Analect. zur vergl. Anat. 1835.] 

•J- [Heart of crocodilus lucius, after Dr. Bischoff.— The venous blood brought by the 
superior venae cavaa (1, 1), and by the inferior cava (2), to the right auricle (3), is 
poured into the right ventricle (6). The arterial blood is transmitted through the 
pulmonary veins (4, 4) to the left auricle (5), and thence to the left ventricle (7). 
The wire (8) shows the course of the venous blood to the arterial trunk (9), which 
gives off the pulmonary arteries (16, 16) and the left aortic arch (15). The wire 
(10) indicates the course of the arterial blood to the arterial trunk (11,) from which 
arise the carotid arteries (13;, and the right aortic arch (14.) Besides the opening be- 
tween the two great arterial trunks, through which the wire (12) is passed, there is a 
communicating branch passing from the right aortic arch to the left, which is conti- 
nued to the posterior extremities, while the right is distributed to the abdominal viscera. 
The similarity between the course of the circulation in this reptile to the fcetus of 
mammalia and birds, and the analogy pointed out by Professor Mayer to exist between 
the left aortic arch of the crocodile and the ductus arteriosus, are very striking.] 

% The amphibia may be arranged in five orders, (as follows.) — 1. Caeciliae, without 
feet and tail, vermiform.— In the first period of their existence they have a branchial 
cavity, in which there are two branchial clefts on each side of the neck, which I have 
discovered in the caecilia hypocyanea ; at a later period they have lungs without bran- 



Fig. 8. 





In the proteidea^— for example, the 
proteus, (fig. 8,)— the arterial trunk 

chiaa or branchial foramina. Their os hyoi- 
ues has four pairs of arches, in the larvae five. 

[This is the order apoda of Mr. T. Bell. 

■See Cyclop, of Anat.] 

2. Derotremata.— The individuals of this 
order have extremities and caudal prolon- 
gation, an opening on each side of the neck 
Without true external or internal branchiae. 
1 hey breathe by means of lungs ; have four 
*eet. The genera are the amphiuma and 
*nenopoma.— [The abranchia of Mr. Bell.] 

3« Proteidea. — These have extremities 

aj id caudal prolongation, and both lungs and 

branchial clefts on each side of the neck, 

wuh external tufted branchiae throughout 

ue. The genera are siren, menobranchus, 

Proteus, axolotes.— [Amphipneurta of Mr. 

^ 4. Salamandrina. — During the first pe- 
n od of their larval condition the salaman- 
dnna have external branchiae and branchial 
clefts, no extremities, but a caudal prolonga- 
tion. In the second period of their existence, 
they have, besides a tail, four extremities, of 
which the anterior appear first ; at the same 
time they have tufted branchiae, and bran- 
chial clefts, with rudiments of lungs. In 
this stage of their developement therefore 
they resemble the permanent state of the proteidea. In the perfect state they retain 
the tail • but their ^chia and branchial clefts disappear when the larval state ceases. 
[Ihe urodela of Mr. T. Bell.] 

5 Batrachia._The frogs and toads [anoura of Mr. Bell].-These in the first stadium 
of their larval condition have a tail and no extremities, and have branchial clefts and 
arches, and external tufted branchiae. In the second period they lose their external 
branch,*, but have internal branchiae on the branchial arches, the branchiae being covered 
dv a mem b r ane which leaves but one opening on the left side in the frog ; they have 
still a tail and no extremities. In the metamorphosis from the larval condition they 
acquire extremities of which the posterior appear first, they lose their branchiae, and 
Nieir tail also wholly disappears by absorption. 

During the larval state of frogs and salamanders, both articulating surfaces of the 
bodies of the vertebrae are excavated conically, as in fishes ; in the caeciliae, derotremata, 
and proteidea this state is persistent.— See J. Mueller in Tiedemann's Zeitschrift f Ur 
Physiol, iv. 2. On the heart of the amphibia 
fi Physiol. Bonn, 1832. 

* [Circulation in the proteus anguinus, after Rusconi. — 1, 1, The pulmonary veins • 
2. left auricle ; 3. vena cava ; 4. hepatic vein ; 5. sinus venosus ; 6. right auricle ; 7. the 
ventricle ; 8. the bulbus arteriosus ; 9. branchial arteries ; 10. branchial veins. Be- 
tween the branchial arteries and veins communicating branches are seen which complete 
the arches. 11. Descending aorta. From the united trunk of the second and third bran-. 

M 2 







divides immediately into several aortic arches on each side, corresponding 
to the branchial arches; the aortic arches unite again posteriorly, form- 
ing the aorta abdominalis. From the aortic arches the great bran- 
chial arteries arise, and the branchial veins terminate in them. 

In the salamander. — In the larva of the salamander the arterial trunk di- 
vides, as in the proteus, chiefly into the branchial arteries which give off 
anastomosing branches to the branchial veins: the branchial veins by their 
union form the main stem of the general arterial system. During the me- 
tamorphosis from the larval state, the circulation in the branchiae gradually 
ceases and becomes limited to the permanent aortic arches.* 

In the frog. — The branchial circu- 
lation in the frog, during the earliest 

Fig. 9-t 

period of its larval condition, when 
it has external branchiae, is similar to 
that in the larva of the salamander. 
During the second period (fig. 9), in 
which it has internal covered bran- 
chiae, and in which the lungs begin to 
be developed, the distribution of the 
vessels is, according to Huschke, 
more like that of fishes ; the arterial 
trunk divides into the branchial ar- 
teries for the four branchial arches, 

the branchial veins collecting into 
large trunks run parallel to the arte- 
ries. In the larvae of the frog, how- 
ever, there is a short anastomosing 
branch connecting the artery and 
vein at the commencement of each 
branchial arch, which does not exist 

in the fish. After the metamorphosis I 

(see fig. 10) there remains on each side but one arterial arch, which unites 
with the one of the opposite side to form the aorta abdominalis, and which 
gives off posteriorly the arteria brachialis. The pulmonary arteries 
and those of the head, although they appear to arise from the commence- 
ment of these two aortic arches, do not really do so; for, when accurately 
examined, each of the two diverging stems into which the bulbus arteri- 

chial vein the pulmonary artery arises, and descends to the lung (14); 12. kidney; 
13. testicle; 15. stomach ; 16. intestine ; 17. vena porta ramifying in the liver.] 

* Rusconi, Amours des salamandres. Milan, 1821. 
t [Diagram of circulation in the tadpole in its second stage.— 1. The vena cava; 2. 
the right auricle ; 3. the pulmonary veins ; 4. the left auricle ; 5. the ventricle ; 6. bul- 
bus arteriosus ; 7. branchial arteries ; 8. branchial veins ; 9. aorta ; 10. pulmonary ar- 
tery arising from fourth branchial arch.] 




osus divides, is found to consist of 
three trunks united, the cavities of 
which, however, are separated by 
thin septa merely. These are the 
remains of the branchial arteries 
which have united to form apparent- 
ly one stem. The middle one of 
these vessels is continuous with the 
aorta. The most inferior gives off 
the pulmonary artery and a vessel to 
the occiput, while the superior one 
forms the arterial trunk from which 
the head is supplied. Near the ori- 
g*n of the arteries of the head there 
*s a glandular enlargement, — the so- 
called carotid gland. This gland is 
formed of minute ramifications of 
tne entprinrr voocoio which again 

Fig. lO.t 

entering vessels, 

unite into a single trunk that issues 
from the mass.* This body is sup- 
posed to be the remains of the capillary vessels of the first branchial 
arch. I have satisfied myself that it has a cavity in its interior, and that 
the stem entering it is continuous till its exit, passing through a spongy 
tissue, which is most dense internally, although the external surface when 
finely injected does present a delicate network, as Huschke describes 
formed from vessels passing in and out. 


The true reptiles 

never possess branchiae, and undergo metamorphosis only during the fcetal 
state, like the other vertebrata. In the earliest period of fcetal life, 
the embryos of all vertebrate animals have clefts in the neck, and, be- 
tween these, arched plates. In these plates run the aortic arches, which 
unite again posteriorly into one common trunk. This was discovered 
by Rathke; it is satisfactorily seen in the embryo of the bird on the third 
day of incubation. A similar structure, but less distinct, exists also in 
niammalia and in man. It is more easily seen in the embryo of 
r ep tiles. In these higher vertebrata there are no real branchiae with 
branchial lamellae, but merely branchial arches, from which in fishes and 
amphibia the branchiae are developed by ramification of the aortic arches, 

This was shown by Huschke. Zeitschrift fiir Physiol, iv. 1. 
1* [Diagram of circulation in the frog. — 1. The vena cava ; 2. the right auricle ; 3. pul- 
monary vein ; 4. left auricle; 5. ventricle ; 6. bulbus arteriosus, which divides into two 
branches (7) ; the division of these branches into three branches by internal septa is in- 
dicated by dotted lines ; 8. aortic arch giving off brachial artery ; 9. pulmonary artery ; 
10. a branch to the occiput • 11. carotid ; 12. descending aorta,] 








k. » 


but which in all other vertebrate classes gradually disappear ; being, it 
would seem, converted into the cornua of the os hyoides.* In all verte- 
brate animals then, during the earliest stage of existence, the main arterial 
stem divides into aortic arches. These arches are indeed persistent in 
reptiles; in some cases two on each side, — as in the true lizards and 
blind worms ; — in other cases one only on each side, — as in serpents. 
In the higher vertebrata, birds, and mammalia, in which there are two 
auricles and two ventricles, it is during the foetal state only that there 
are several aortic arches ; at first, indeed, several on each side, which 
unite posteriorly to form the descending aorta. In birds the most 
anterior of the three arches gives off the vessels for the anterior part of 
the body ; the most posterior, the pulmonary artery : at a later stage 
of developement, and throughout foetal life, there are two arches from 
the right ventricle, from which the Fig. ll.f 

pulmonary arteries are given off; 

and one arterial stem from the left i\. 

ventricle, w T hich gives origin to the 
vessels of the anterior part of the 
body, and forms the arch of the 
aorta. After the bird has escaped 
from the shell, the pulmonary arte- 
ries also become independent, from 
the anastomoses between the arte- 
rial arches that arise from the right 
ventricle, with the aortic arch from 
the left ventricle, ceasing to exist. £ 
In mammalia there are during foetal 
life two aortic arches, which unite 
posteriorly to form the descending 
aorta (see fig. 11). Of these, one 
arises from the left ventricle, and 
gives off the arteries for the upper 
part of the body; the other from the 
right ventricle gives off the pulmo- 
nary arteries as lateral branches. The 

* J. Miiller, Meckel's Archiv. 1830, p. 419. 

f [Diagram of the circulation in the human foetus. 1, 1. Umbilical arteries ; 2. umbi- 
lical vein. The blood of the umbilical vein is partly distributed to the liver, in the 
right lobe of which it becomes mixed with the blood of the porta ; in part it passes 
directly by the ductus venosus (3), to the vena cava inferior (4). 5. Hepatic veins ; 6. 
superior cava ; 7. right auricle ; 8. pulmonary veins ; 9. left auricle; 10. left ventri- 
cle; 11. ascending aorta or left aortic arch ; 12, vessels to the head and upper extre- 
mities ; 13. right ventricle ; 14. ductus arteriosus, or right aortic arch ; 15. descending 


$ S. Huschke, Isis, 1828. 160. 

, . i ■.- 




continuation of this latter arch, namely, the ductus arteriosus, by which 
it unites with the aortic arch, at last ceases to be pervious, and then 
the pulmonary arteries become the sole branches of the trunk arising 
from the right ventricle. The arch of the aorta, or arcus ventriculi 
smistri, in mammalia, turns from the left side behind the oesophagus, 
while in birds it turns from the right side ; when it is recollected that 
in the embryo state of both classes of animals there are several arterial 
arches on each side, this apparent anomaly becomes easily intelligible, 
-Besides the communication between the two arterial arches, there is in 
the foetus another means of communication between the two sides of 
the heart, namely, the foramen ovale. When either this opening, or the 
ductus arteriosus, remains unclosed after birth, the arterial and the venous 
blood are mixed, and the ccerulean disease is produced. 

Varieties in the circulation dependent on the relation of the lesser and 
9 r eater circulation. — As soon as a true circulation is met with in ascending 
the animal scale, all further modifications depend on the relation in which 
the vessels of the respiratory organs, or the lesser circulation, stand to 
the vessels of the body, or greater circulation. Thus either a portion 
°^ly of the blood is aerated in the course of the greater or systemic 
circulation, in which case the lesser circulation, to use Cuvier's expres- 
sion, is merely a fraction of the greater, or all the blood must first pass 
through the lesser circulation of the lungs or branchiae, before it is dis- 
tributed to the body generally. 

The varieties which nature presents in the origin of the arteries and 
veins of the respiratory organs from the systemic circulation are very 
numerous, and seem indeed to comprehend all imaginable forms. 
They may be arranged as follow : 

A. The lesser circulation a fraction of the greater circulation. 

1. The lesser circulation a part of the venous system : example, in the 

conchifera, if Bojanus is correct, a portion of the venous blood returns 

immediately to the auricles, while the greater part previously traverses 
the branchiae. 

2. The lesser circulation a part of the arterial system : example, in 
the proteidea, and in the frogs and salamanders during the larval con- 
dition, the aortic arches give off the branchial arteries and receive the 
branchial veins as lateral branches. 

3. The lesser circulation forming a part of the arterial and venous 
systems : example, a, The salamander and frog in their perfect state have 
no longer branchiae, the proteidea retain both branchiae and lungs 
throughout their existence ; in both, the pulmonary arteries are branches 
of the aortic arches, and the pulmonary veins terminate in the left 
auricle, the veins of the body in the right auricle, as has been discover • 

6, In the true 


reptiles, the pulmonary artery arises from the main arterial trunk, or 


ge and M. Weber 



from the ventricle itself with the arteries for the body ; the branchial 
i empty themselves into the left auricle, the veins of the body into 

the right auricle. 

B. The lesser circulation opposed to, or distinct from, the greater 


1. The lesser circulation commencing in the veins of the body 
and terminating in the heart : example, the mollusca and higher 

2. The lesser circulation commencing in the branchial arteries which 

arise from the great arterial stem, or bulbus aortse, and returning by the 

branchial veins to a new arterial stem for the rest of the body : example, 

3. The lesser circulation arising from the pulmonary ventricle and 
returning to the ventricle of the systemic circulation : a, In the sepia, 
the aortic heart and the two branchial hearts are separate and without 
auricles: b, In birds and mammalia there is one pulmonary and one 
aortic ventricle, each with an auricle, united to form one heart : the 
pulmonary veins open into the auricle of the left or aortic ventricle ; the 
veins of the body,— the venae cavae,— into the auricle of the right or 
pulmonary ventricle. 

So that as regards the relation which the pulmonic or branchial cir- 
culation bears to the systemic circulation, reptiles and amphibia would 
appear to be inferior in the scale of organisation to fishes, to the majority 
of mollusca, and to Crustacea. But Cuvier rightly observes, that respira- 
tion in water is much more imperfect than when performed in the air, 
and consequently that the imperfect respiration of the mollusca, Crus- 
tacea, and fishes in the water, although all their blood passes through 
the respiratory organs, does not differ in result from the more perfect 
pulmonary respiration of reptiles, in which the lesser circulation is only 
a fraction of the systemic circulation. Still those gasteropoda which 
respire by means of pulmonary sacs would appear to be higher in the 
scale than the reptiles with a similar mode of respiration, inasmuch as a 
part only of the blood in the latter, in the former all the blood, is aerated 
before it enters the general circulation. But it must be remembered 
that in the lungs of the gasteropoda the number of the vessels and their 
ramification, and consequently the exposure of the blood to the air, are 
much less considerable than in the lungs of reptiles. 

The larvse of the amphibia respire by means of branchiae in the 
water ; and since in that condition a portion only, although a large por- 
tion of the blood, is aerated before it enters the systemic circulation, 
these animals are in this respect certainly inferior to fishes. But we 
have already seen that this arrangement in the larvae of the amphibia is 
necessary in order that the pulmonary circulation may afterwards be de- 
veloped from the previous branchial circulation. 



Portal circulation. — Besides the lesser or pulmonary circulation, there 
is in all vertebrate animals another still smaller circulation, which, like 
the branchial circulation of amphibia, is a "fraction" merely of the 
general circulation. This is the portal circulation ; it is a mere subordi- 
nate part of the venous circulation, in which the blood makes an ad- 
ditional circuit before it joins the rest of the venous blood. There are 
m the vertebrate classes two portal circulations ; one of the liver, the 
other of the kidneys (fig. 12). The latter exists only in reptiles, amphi- 
bia, and fishes ; the former in all the vertebrata. 

In mammalia, including man, the veins which collect the blood from 
the spleen, stomach, intestines, gall-bladder, and pancreas, unite to form 
the portal vein, which ramifies through the liver like an artery: from the 
capillary vessels of the liver, the 
Wood, a part of which was supplied 
by the hepatic artery, returns through 
the hepatic veins to the vena cava, 
m which it becomes mingled with 
the venous blood of other parts. In 
the other classes of the vertebrata, 
a part of the blood of the lower ex- 

Fig. 12 * 

tremities also is carried to the por- 
tal vein ; and in fishes sometimes the 
blood from the air-bladder and 


genital organs.f 

In reptiles and amphibia, the 
kidneys have, besides the renal arte- 
ries, portal veins (fig, 12, 1), which 
bring to them a part of the blood of the 
posterior extremities, and of the tail. 
In these animals the blood returned 
from the posterior extremities, from the abdominal muscles, and from 
the tail, goes partly to the liver, and partly to the kidneys ; in frogs and 
salamanders to these viscera only ; while in some reptiles, as the croco- 
dile, a portion of it is sent to the vena cava. In some fishes, for 


* [Venous circulation in the toad.— 1. Afferent renal vein ramifying on the poste- 
rior surface of the kidney (k) ; 2. vein from the muscles of the back joining 
the afferent renal vein ; 3. a branch coming from the interior of the spinal canal ; 5. 
communicating branch between the ischiadic, or afferent renal, and the anterior abdo- 
minal vein (6), which runs over the surface of the abdomen and terminates in the 
vena portae (7), which is formed chiefly by the veins of the stomach (S) and 
intestines (I) • 8. the vena cava formed principally by the efferent renal veins, which 
run on the anterior surface of the kidney (K). The veins of the ovaries (O), also 
pour their blood into the cava, while the veins (9) of the oviduct (OD), join the 

afferent vein of the kidney.] 

t See Jacobson, Nicolai, and Rathke. 





example, the gadus, the blood of the tail and middle part of the body 
goes wholly to the kidneys (see fig. 5) ; in others, the venous blood of 
the posterior parts of the body is distributed to the kidneys, liver, and 
vena cava, as is the case in the carp, pike, and perch.* 

•Meckel, who considers these portal veins which carry blood to the 
kidneys to be ordinary venous trunks conveying it from them, founds his 
opinion chiefly on the class of birds, in which Jacobson incorrectly de- 
scribed portal veins going to the kidneys; but the non-existence of 
these veins in birds, which had been previously proved by Nicolai, is no 
argument for their not existing in reptiles, amphibia, and fishes, in 
which classes indeed Nicolai has established their presence. 

Essential characters of 

The principal impelling power of 

the circulation is the rhythmic motion of the heart. The heart is that 
part of the vascular system which, from having muscular parietes, which 
the blood-vessels do not generally possess, is endowed with contractility. 
In its simplest form, therefore, the heart still resembles a vessel ; this is 
exemplified by the vessel-like multiple hearts which constitute at the 
same time the main vascular trunks of the annelides, by the contractile 
vascular trunks on the intestinal canal of the holothuria, and by the dor- 
sal vessel of insects, which is divided into a series of chambers. The 
correctness of this view is very evident on examining the organ in 
different orders of the Crustacea : thus, in the squillae the heart is a con- 
tractile dorsal vessel, while in the decapoda it presents one short and 
circumscribed chamber or ventricle. 

In the embryo of the higher animals the heart is at first tubular, and 
is nothing more than the contractile part of the vessels at which the 
venous trunks are reflected into the arterial stem. 

In the adult too of the higher animals the heart consists of a short 
double muscular sac, but the contractile substance is continued for 
a certain extent on the venous trunks that open into it, and in fishes 
and reptiles, upon a part of the arterial stem,— the so-called bulbus 
aortae. In the frog the trunks of the venae cavae can be most distinctly 
seen to contract regularly like the heart. This was observed by 
Haller,t Spallanzani, and Wedemeyer. The contraction appears to 
me to extend on the inferior cava as far as the liver ; and is still con- 
tinued, and with regularity, in the venous stems, after the heart is 
removed. First, the cavae contract, then the auricles, next the ven- 
tricles, and lastly the bulbus aortae. I have observed contraction of the 
great veins in the mammalia, both in the young marten and in the young 
cat ; in these animals, however, the contraction of the venae cavse and 
pulmonary veins is synchronous with the contraction of the auricles. 


* Jacobson, Meckel's Archiv. 1817. 147. Nicolai, Isis, 1826. 404. 
t Elementa Physiol, t. i. 125. 



In young animals the most distinct contractions of the pulmonary- 
veins are perceptible as far as these vessels can be followed in the 
substance of the lungs. The contraction of the cardiac end of the 
superior vena cava is as distinct. But, during the contraction, the 
distance to which the contractile substance of the cavse extends may be 
distinguished ; beyond this limit the vena cava exhibits not the slightest 
contraction, but becomes rather turgid and distended by blood at the 
time that the parts of the vessel contiguous to the right auricle are 
contracted. At the origin of the vena cava of serpents Retzius has 
described a layer of peculiar fibres, and E. H. Weber has found the 
same in the inferior cava of mammalia. 

These observations indicate, that in its simplest form the heart is 
merely that part of the vascular system which is furnished with muscu- 
lar structure, and endued with the power of active motion ; and that 
lfc is still the heart when, as in the lower animals, it has the form of 

simple contractile vascular stem. The rest of the vascular system 

consists merely of tubular canals, which, in reference to motion, are 

passive, but may exert other important influences on the blood. 

Thus, for example, by virtue of a power, the nature of which is not 

known, they maintain the fluidity of the blood as long as it is in 

niotion; and the interchange of matters between the blood and the 

tissues which takes place through their pariet^s is effected by their in- 




The heart of adult man in the middle period of life contracts seventy 
to seventy-five times in a minute ; the frequency of its action gradually 
diminishes from the commencement to the end of life, thus : 

In the embryo the number of beats in a minute is 

Just after birth . . « 

During the first year .... 

During the second year 

During the third year .... 

About the seventh year 

About the fourteenth year 

In the middle period of life - 

In old age '..... 

from 130 to 140 

115 to 130 
100 to 115 

90 to 100 
85 to 90 
80 to 85 
70 to 75 
50 to 65 

In persons of sanguine temperament the heart beats somewhat more 
frequently than in those of the phlegmatic ; and in the female sex more 
frequently than in the male. The number of the pulsations in a minute 
varies very much in different animals. 

* I have given a more elaborate description of the various forms presented by the 
circulation in the animal kingdom, in Burdach's Physiologie, B. iv. 






In fishes the number of beats in a minute is 

In the frog 

In birds . • « 

In rabbits 

In the cat . . . • 







from 20 to 24 

about 60 
from 100 to 140 

about 120 

. 110 



After a meal the heart's action is accelerated, and still more so during 
bodily exertion ; it is slower during sleep. According to Parrot/ the 
frequency of the pulse increases in a corresponding ratio with the eleva- 
tion above the sea : 

When the pulse at the level of the sea ^ 
At 1000 metres t above its level, it was 

1500 . 

2000 • 

2500 . 

3000 . . . 

4000 . . 





In inflammations and fevers the pulse is much more frequent than 
during health. When the vital powers decline, it becomes frequent 
and feeble. In nervous affections with more oppression than exhaustion 
of the forces, the pulse is often remarkably slow. 

If the heart of a living mammiferous animal or bird is laid bare, the 
two ventricles are seen to contract simultaneously ; the two auricles 
with the commencement of the pulmonary veins and of the venee cavse 
also contract simultaneously, the contraction of the auricles and that of 
the ventricles not being synchronous. In warm-blooded animals the 
auricles contract immediately before the ventricle. In the frog the 
contractions of the venous trunks, of the auricles, the ventricle, and 
the bulbus aortse appeared to me to follow the order in which I have 

named the parts, the intervals between the four contractions being 
nearly equal ; so that the same interval of time elapsed from the con- 
traction of the auricles to the contraction of the ventricle, as between 
the contraction of the ventricle and that of the bulb of the aorta. I 
am convinced, from repeated observations, that the auricles and ventricle 
do not, as Oesterreicher J asserts, alternate in action at equal intervals 
like the motions of the pendulum, but that the time that intervenes 
between the contraction of the auricles and the contraction of the 
ventricle is much less than that which elapses from the moment of 
the contractions of the ventricle to the moment when the auricles 
again act ; and that generally the contraction of the bulbus aortae and 

* Froriep's Notizen, 212. See also Niek, iiber die Bedingungen der Hanfigkeit des 
Pulsus. Tubingen, 1826. 

-|- [A metre is about three feet three inches.] 

+ Lehre vom Kreislauf des Blutes. 

Niirnb. 1826. 

* .^ 






venous trunks occur in the interval of time last indicated. In warm- 

blooded animals I have 

seen the contractions of the auricle cease 

altogether for some moments, which must have been caused by the 
injury inflicted in making the observation. Under ordinary circum- 
stances, the auricular contraction was always a very quick motion imme- 
diately preceding the action of the ventricle, so that the interval of 
time from the contraction of the auricles to the contraction of the 
ventricle is at any rate very much shorter than the interval between 
the contraction of the ventricles and that of the auricles. 



relaxed, and in which the blood is poured from the contiguous veins 
into the cavities of the heart, to fill the vacuum consequent on the 
relaxation of its fibres ; the valves of the heart being so arranged as to 
allow the influx of the blood from the veins. The dilatation of the 
heart was supposed by Bichat, and some other French physiologists, to 

be an active movement, but Oesterreicher* has by a very ingenious 
experiment refuted this supposition. He removed the heart of a frog 
*rom the body, and laid upon it a substance sufficiently heavy to press 
*t flat, and yet so small as not to conceal the heart from view ; he then 
observed that during the contraction of the heart the weight was 
raised, but that during dilatation the heart remained flat. This experi- 
ment shows that the dilatation of the heart is not a muscular act; at 
the same time,, however, it must be recollected that the walls of the 
heart during life cannot become so relaxed at the time of the diastole, 
as in a heart removed from the body, even although the cavities of 
the heart were not filled with blood ; for during life the capillary 

vessels of its substance are at the time of relaxation injected with 
blood, which during the contraction is pressed out of them, and this 
filling of its vessels must give it some degree of firmness and rigidity. 

The contraction of the ventricles of the heart would drive the blood 
into the auricles and veins, as well as into the arteries, if the valves 
were not so constructed and attached as to allow the expulsion of 
the blood only in certain directions. There are certainly no valves to 
prevent the auricles from forcing the blood into the veins ; but the 
stream of venous blood towards the heart checks its regurgitation 
m this direction, while its passage from the auricle into the ventricle 
is free, for the valve at the auriculo-ventricular orifice is so attached 
that it allows the blood to flow into the ventricle; but, when the 
ventricle contracts, the same valve prevents the regurgitation of the 
blood into the auricle, being by the pressure of the blood spread out 
so as to close the orifice. The escape of the blood from the ventricle 
into the great arteries is unimpeded, the pouch-shaped semilunar 

* Loc. cit. p. 33. 






# ■ 

valves situated at the arterial orifice of the ventricle being separated 
from each other, and laid close to the walls of the artery by the stream 
of blood forced into it. And when the contraction of the ventricle 
ceases, regurgitation from the arteries cannot take place, for the blood 
itself presses down the valves towards the centre of the vessel, and 
spreads them out so as to close the arterial orifices of the ventricles. 
The heart by this arrangement of the valves is constituted a kind 
of forcing-pump, like the common syringe with two valves, of which 
one admits the fluid on raising the piston, but is closed again when the 


piston is forced down, while the other opens for the escape of the 
water, but closes when the piston is raised, so as to prevent the 
regurgitation of the fluid already forced through it. 

The vascular system must be regarded as being constantly filled with 
blood in all parts. The heart's cavities alone contract at each beat 
so as to expel nearly all their contents ; but several observations show 
that even the ventricles do not empty themselves completely during 
their contraction. The vessels, on the other hand, from the com- 
mencement of the arteries to the capillary vessels, and thence to the 
insertion of the venous trunks into the heart, are filled with blood, 
both during the contraction of the ventricles and at the time of their 
relaxation ; neither air nor a vacuum exists in any part of the vascular 
system. So that the contraction of the aortic or left ventricle cannot 
advance the blood in the arteries except by forcing on the column of 
blood already contained in them ; and the advance of the column is 
proportionate to the space which the blood forced through the aortic 
orifice by each contraction of the ventricle — namely, from one to two 

- ■ 

ounces — occupies in the commencement of the aorta. When the con- 
traction of the ventricle remits, the cause of the motion ceases, but 
the elasticity of the arteries overcomes the resistance offered by friction 
in the minute vessels, and still forces the blood onwards ; a continuous 
current is thus produced from the aortic valves to the capillary vessels ; 
when the aortic ventricle again contracts, and again forces one or two 
ounces of blood into the aorta, the current is accelerated, and the 
column of blood is advanced to the same extent as before. The result 
of this succession of actions must be, that exactly the same quantity 
of blood enters the heart from the veins as was expelled from it in 
the same space of time by the contraction of the ventricles ; for the 
whole mass of blood forms one great circle from the heart to the 
heart, — a circle, at each and every point of which the same quantity 
of blood must pass within a given time. By their contraction the 
ventricles are never completely emptied, for, when the contraction ceases, 
the blood impelled by the vis a tergo immediately flows from the veins 
and auricles into the ventricles to fill the impending vacuum ; it is 


the same with the auricles. 





The pressure of the column of blood against the elastic walls of 
the arteries at every contraction of the ventricle produces what is 
called the pulse. The phenomenon will be more particularly consider- 
ed at a future page; here it is only necessary to remark, that the 
sensible pulse of the arteries is synchronous, or nearly so, with the 
contraction of the ventricle ; the arterial pulse is somewhat later than 
the heart's beat, but the difference of time is scarcely perceptible. In 


capillaries and veins the pulse is not detectible. 


ne arterial pulse. The heart's impulse is the shock communicated by 
tn e apex of the heart to the walls of the thorax in the neighbourhood of 
the fifth and sixth rib. But it is not at present known whether it is 
during its contraction, or during its dilatation by the blood entering 
* r om the veins and auricles, that the heart strikes against the ribs. 

(!•) Till latterly, the heart's impulse had been generally attributed 
to the contraction of the ventricles. Some imagined that the ventricles 

ur wg the systole become lengthened, and from that cause strike the 
walls of the chest by their apex. No such lengthening, however, takes 
P ac e. Senac* attributed the impulse to the distension of the arteries 

y the blood during the contraction of the ventricles, to the filling of 

e auricles at the same time, and to the straightening of the arch 

ot the aorta by the impulse of the blood forced into it. But, as Carson 

ias remarked, it is an error to suppose that an arched and moveable 

ube has a tendency to become straight when fluid is injected into 
it, for the pressure of the fluid on its walls is equally strong in all 

(2.) Corrigan, Stokes, and Burdach have very recently advanced the 
doctrine that the impulse of the heart against the thoracic parietes is 
produced by the distension of the ventricles at the moment that it 
is brought to its greatest degree by the contraction of the auricles, 
and consequently that it precedes the contraction of the ventricles.t To 
inform myself, if possible, whether this view is correct, I made some ex- 
periments on a goat whose thorax was opened during life; Professor 
Albers was present. Our observations, however, did not convince us that 
the opinion of Corrigan, Stokes, and Burdach is the correct one; on the 
contrary, while the animal lay on its back, we saw distinctly that the 
heart was elevated at every contraction of the ventricles, and the apex 
particularly. When the hand was laid upon the heart, the shock during 
the contraction of the ventricles was so forcible and instantaneous that it 
seemed impossible to attribute the heart's beat or the impulse against the 
ribs to any other cause, while during the diastole we felt no shock. The 
heart does not, however, recede from the thoracic parietes during the 

* Traite de la structure du Cceur. Paris, 174,9. 
f See Burdach's Physiol, vol. iv. p. 219—222. 










diastole. During life, the heart lies with its apex close to the walls of 
the chest, and the shock communicated to these walls by the heart 
by the contraction of the ventricles is felt externally, constituting the 
heart's impulse ; to give the shock, the heart does not require any great 
change of position. 

Sounds of the heart. — When the ear, or a stethoscope, is placed over the 
precordial region, two sounds are heard following each other quickly at 
every beat of the heart. I have sometimes heard them in my own person 
at night when lying on the left side. Like the heart's impulse, these 
sounds are followed by a pause. The interval of time between the two 
sounds compared with the pause is, according to my observation, in the 
proportion of 1 to 3, or about ^th of the time occupied by the beat and 
pause together, — that is, about ^th of a second* From repeated and long 
continued observations I am satisfied that the first sound is synchronous 
with the impulse at the chest, and nearly synchronous also with the pulse 
of the facial artery, which is only -g^th of a second later than the impulse 
at the chest. The extent to which the first sound was distinctly heard in 
a healthy female did not exceed the space in which the impulse was felt; 
but the second sound was audible in nearly the whole extent of the chest, 


as high as the clavicles. In pregnant women the two sounds of the foetal 
heart are heard through the abdominal parietes. 

Laennec attributed the first sound to the contraction of the ventricles ; 
the second he ascribed to the action of the auricles, which, however, is 
indubitably an error, since the contraction of the auricles immediately 
precedes the contraction of the ventricles. Corrigan, Stokes, Pigeaux, 
and Burdach attribute the first sound to the contraction of the auricles, 
the second to the contraction of the ventricles. Now the arterial pulse, 
which is known to depend on the contraction of the ventricles, is nearly 
s\'nchronous with the heart's impulse, being only ^yth of a second later 
than it ; while the second sound is not heard until ^th of a second after 
the impulse. It is evident, therefore, that this second sound cannot be 
dependent on the contraction of the ventricles ; and it is also evident that 
the impulse at the chest which is synchronous with the first sound 
cannot be ascribed to the distension of the ventricles and contraction of 
the auricles, as Burdach imagines. 

Dr. Williams believes the first sound to be the effect of the contrac- 
tions of the ventricles and auricles succeeding each other with great ra- 
pidity ; the second sound he attributes to the action of the valves. Des- 
pine maintains, that the first sound is the effect of the contraction of the 
ventricles, the second that of their dilatation.* Dr. Hope considers the 
first sound to be the effect of the contraction of the ventricles, which the 
contraction of the auricles precedes ; the second sound to be the effect of 
distension of the ventricles by the blood which is impelled by the vis a 

* Burdach's Physiol, iv. bd. 223. 





tergo from the veins into the auricle, and thence into the ventricle before 
the contraction of the auricle takes place.* 

I forbear giving an opinion as to the exact mode of the production of 
the two sounds, and shall merely state a few facts which I think I have 
determined with considerable certainty. These facts are, that the in- 
terval between the two sounds is equal to |th the time occupied by an 
entire beat and pause ; that the first sound is synchronous with the 
J nipulse ; and that the arterial pulse is but a small fraction of a second 
later. Being convinced that the impulse is produced by the contrac- 
tion of the ventricles, I am equally certain that the first sound also 
a nses from the contraction, the second from the dilatation of the 

ventricles. Ma 

ri nients, that the sounds cease as soon as the thorax of the animal is 
°pened, and return again when a hard body is laid upon the heart 
to receive its impulses. He attributes the first sound, as we do, to the 
contraction of the ventricles, and to the impulse of the apex of the heart 
a gainst the ribs ; the second sound to a similar impulse produced by the 



-uie greater circulation is the course of the blood from the left side of 
the heart through the arteries of the body, and back again through the 
veins to the right side of the heart. The course of the blood from the 
ri gut side of the heart through the pulmonary arteries to the lungs, and 
back to the left side of the heart through the pulmonary veins, is called 
the lesser circulation. The blood therefore in fact makes but one circuit, 
of which there are two divisions ; in each of these the blood 

through capillary vessels from arteries to veins. 



The same quantity of blood enters the right auricle from the superior 
and inferior cavae, and from the great coronary veins, as is impelled during 
the same period of time by the left ventricle through the arteries of the 
body. On the contraction of the auricle, the entrance of the blood of 
the veins is suddenly interrupted; but, when the auricle becomes relaxed, 
the blood rushes into it, and into the right ventricle as soon as its con- 
traction also ceases. The auricle now contracts, and immediately after- 
wards the ventricle. The auricle contracting forces the blood through 
that orifice which remains free. It cannot regurgitate into the venae 

* Froriep's Notiz. 735. See Dr. Hope's Treatise on Diseases of the Heart. 

t Ann. des sc. nat. 1834. 

% [The experiments of M. Magendie have been repeated by Dr. Hope and M. Bouil- 
land, and the results were unfavourable to his theory. M. Bouilland attributes both 
sounds to the action of the valves. Dr. Carswell was the first who, led by the observation 
of some cases of disease of the heart and aorta, suspected that the second sound was pro- 
duced by the closing of the sigmoid valves by the pressure of the columns of blood 
in the aorta and pulmonary artery.] 





cava* because it is in them opposed by the stream of venous blood which 
continues to be impelled towards the heart by the vis a tergo ; and the 
opening of the coronary veins is closed, its valve being applied to the ori- 
fice by the pressure of the blood in the auricle. The blood flows there- 
fore into the right ventricle, which during the contraction of the auricle 
had become partially dilated and is now completely distended. While 
the right auricle is again dilating to receive the blood of the veins, the right 
ventricle contracts ; and the blood, which cannot regurgitate into the au- 
ricle on account of the tricuspid valve being spread out by the pressure of 

the blood so as to close the auriculo-ventricular orifice, is driven into the 
pulmonary artery. 

In this manner the venous blood returning from the body is, by the 
agency of the right side of the heart, transmitted to the pulmonary cir- 
culation. All the blood contained in the auricle is not, however, forced 
by its contraction into the ventricle. A portion regurgitates into the 
superior and inferior vena cava ; or, at any rate, the contraction of the 
auricle checks the flow of blood from the venous trunks towards the 
heart, which otherwise must continue uninterruptedly. When animals 
are opened during life, the great veins are seen to become turgid at the 
time of each contraction of the auricle ; and in the larva of the triton I 
have seen the blood, in the inferior cava and hepatic veins, advance in 
periodic jerks only. When the escape of the blood from the ventricle into 
the pulmonary artery is impeded from any cause, — whether from organic 
change in the pulmonary artery, ossification of the semilunar valves, or 
impediment to the motion of the blood in the lungs, — the regurgitation 
into the veins is necessarily increased. The regurgitation, or rather, pe- 
riodic arrest of the blood in the great venous trunks, is called the pulsus 
venosus. It cannot extend far, on account of the yielding nature of the 
vein ; that portion only of the venous system which is near the heart is 
affected by it. 

The blood, once in the arteria pulmonalis, cannot return when the ven- 
tricle becomes relaxed, because the column of blood in the artery itself 
spreads out the semilunar valves at the mouth of the artery and closes 
it. The course of the blood from the right ventricle, through the lungs, 
to the left side of the heart, is called the lesser circulation ; it does not 
really form a circle, for the blood does not return to the point from which 
it started. It is only a part of the course of the whole circulation, and 
would be better named the pulmonic course of the blood, in opposition 
to the systemic course of the blood, which together with it forms an entire 
circuit or circulation. In the pulmonic course, the venous blood expelled 
from the right ventricle by successive new portions of blood, flows from the 
branches of the pulmonary artery into the capillary vessels of the lungs, 
and through these capillary vessels, — in its transit through which it be- 
comes scarlet, or arterial, — into the pulmonary veins, and is by these 
poured into the left auricle. The capillary vessels in the lungs are, as in 





other parts, the net-work of minute vessels, which intervene between the 
smallest branches of the arteries and the radicles of the veins; but here 
the meshes of the net-work are extraordinarily small. The innumerable 
capillaries, that constitute the net-work, are enclosed in the delicate 
Membrane forming the cells in which the last branches of the bronchi 
terminate. The membrane that forms the cells is a continuation 
°t the mucous membrane of the trachea, and is, consequently, continuous 
throughout the lungs. The lungs, therefore, — omitting from conside- 
ration the bronchial tubes, arteries and veins, — must be regarded as a 
delicate membrane traversed by a net-work of capillary vessels and 
folded in the form of cells, so as to produce a very extensive surface in 
a small space; the process of respiration being effected by the contact 
°f the air, which enters by the bronchi, with the inner surface of these 
ce 'ls, in the parietes of which the particles of blood circulate in most 
minute currents. 

In the simpler animals, as in the naked amphibia, the lungs are, 
deed, mere sacs, with internal cellular folds. In branchiae also, — the 
second form of respiratory organ, — the essential character is the great 
developement of surface in a small space ; but in them the developement 
of respiratory surface is towards the exterior ; in the lungs it is towards 
the interior, either in the form of sacs or of ramified tubes. In branchiae, 
as m lungs, the blood is distributed over an immense extent of surface, 
by means of the reticulated capillary vessels of all the branchial plates 
and lamellae, each of which has its small artery, which, at the extremity 
of the lamella, is reflected into a small vein, while numerous capillary 
branches keep up anastomoses between the two, across the breadth of 

the branchial lamella. In frogs and salamanders, the motion of the blood 
through the capillary vessels of the sacculated lungs can be subjected to 
observation by means of the microscope.* The spaces between the 
streams of blood are, according to my observations, islets, distributed 
with perfect regularity, and scarcely larger in diameter than the currents 
themselves. The motion of the blood is seen still more distinctly in the 
capillary vessels of the branchiae of the larva of the salamander, f The 
branches of the pulmonary arteries and veins in the lungs of salamanders, 
frogs, and toads, according to Dr. Marshall Hall's description,^ which is 
most exact, run constantly parallel to each other; in the angle formed 
by two arterial branches, there is always a venous branch, in the angles 
between two venous branches always a branch of an artery. In the 

* See the representations of Cowper, in Philos. Transact, abridged, vol. v. p. 331 ; 
of the lungs of the salamander, by Prevost and Dumas, in Magendie's Physiology, 
t. ii. and in Dr. Milligan's translation. 

t Ruseoni, Delia circolazione dellelarve delle Salam. aquat. Pavia, 1817. Amours 
des Salam. aquat., Milan, 1821, in which, however, the transverse branches of the 
branchial laminae are not noticed. Steinbach, Analecten f iir Naturkunde. Fiirth, 1802. 

t A Critical and Experimental Essay on the Circulation of the Blood j London, 1831 ; 
plates 5—8. 

N 2 



septa of the pulmonary cells, which project into the interior of the lungs, 

the arterial and venous branches are 
so distributed that the small venous 
twigs run along the inner border of 
the septa. The ultimate branches 
of the arteries and veins termi- 
nate abruptly in an intermediate 

Fig. 13. 


net-work of capillaries (fi 



while, in all other organs, the rami- 
fication of the vessels still continues, 
passing imperceptibly into the capil- 
lary net-work. The ultimate branches 
of the pulmonary arteries and veins 
are throughout perforated like sieves, 
to give off and receive the blood of 
the capillary vessels. Dr. Marshall 
Hall's representations of the capil- 
lary circulation in different parts are 
extremely interesting, particularly the 8th plate. 

Destruction of the capillary net-work of the pulmonary cells and of 
the air-cells themselves by inflammation, suppuration, or structural de- 
generations, has two very important consequences ; in the first place, 
diminution of the respiring surface, the effect of which may be imper- 
fect formation of the blood, and at last wasting of the body ; secondly, 
diminution of the number of channels through which the blood must 
pass, and, consequently, impediment to its course from the right to the 
left cavities of the heart, and thence to the general system. In warm- 
blooded animals, in which all the blood must pass through the capillary 
system of the lungs before it can arrive at the great aortic circulation, 
any diminution of the extent of this pulmonic capillary system must be 
productive of impediment to the circulation generally; and, in patients 
suffering under pulmonary disease, excessive action of the heart, tend- 
ency to congestion of blood in the lungs, disposition to inflammation of 
these organs, and feverish excitement, must be frequently observed. Any 
other organ might be wholly destroyed without the circulation being im- 
peded in the other organs of the body, but the loss of a portion of the 
lungs is a source of obstruction to the circulation generally; hence it is 
evident that persons suffering with pulmonary disease ought to avoid 
every thing which might produce still greater impediment and excite- 
ment in the circulation. From this consideration may also be explained 
why extensive destruction of other parts, unless accompanied by a con- 
stant draining of the fluids of the body, do not always excite fever, 


* [Fig. 13, representing the circulation in the lung of the toad, is copied from the 
plate in Dr. Marshall Hall's work, to which our author alludes. The arrows indicate 
the course of the blood.] 



while diseases affecting the substance of the lungs are so prone to be 
attended with hectic. Disorganisation in other parts ordinarily produces 
merely the local effects of impediments to the circulation ; for instance, 
congestion of blood and effusion of serum, in the form of local dropsies, 
such as ascites, in cases of disorganisation of the liver, &c. — a termi- 
nation in effusion, which is proportionally rare in cases of disorganisation 
of the lungs. Gaspard has shown, that death is inevitable, and comes on 
y er y rapidly, when the circulation in the capillary vessels of the lungs 
>s obstructed by foreign substances; for instance, by oil, mucus, 



talhc mercury, powdered charcoal, and powdered sulphur, injected into 
the veins. 

Ihe pulmonary circulation would be perfectly isolated from that of 

!e body, were it not that the bronchial arteries communicate with the 

small branches of the pulmonary artery. When the pulmonary artery 

and its branches are narrowed, the anastomoses between them and the 

onchial arteries become enlarged. 

At the chemical changes which the blood undergoes in the lungs are 

arrested by suspension of the respiratory movements, or by breathing 

^respirable gases, the blood ceases to acquire the arterial character in 

the lungs, and returns of a dark red colour. 


b. Greater or systemic circulation. 

A he blood, having assumed its arterial colour, flows from the pulmonary 
veins into the left auricle; and then commences the greater circulation, or, 
more correctly, the systemic portion of the circulation, in which the blood 
is impelled into the arteries, and from thence into the capillary system of 

the body, where it acquires a dark red colour, and returns from the capil- 
laries through th e veins to the right side of the heart. When the auri- 
cles dilate, the blood of the pulmonary veins rushes into the left auricle, 
and a part of it enters the left ventricle. As soon as the muscular contrac- 
tion of the ventricle has ceased, the auricle contracts, and impels the blood 
mto the dilated ventricle, which is thus filled to its greatest capacity, 
uring the contraction of the left ventricle which now follows, the mitral 
v alve closes the auriculo-ventricular orifice; and the blood, forcing asunder 
the semilunar valves at the mouth of the aorta, flows into that vessel. Re- 
flux from the aorta into the ventricle cannot occur, for the blood, re-acted 
u pon by the elastic coats of the vessel, presses down the pouch-shaped 
semilunar valves so as to close the aortic orifice. The left ventricle con- 
tracts with much greater force than the right ventricle, the walls of the 
former being in the adult, as is well known, three times thicker than those 
°f the latter. The left ventricle requires greater power on account of 
the systemic circulation being more extensive than the pulmonic circula- 
tion, and on account of the much greater resistance which must be pro- 
duced by friction in the capillary vessels of all the organs of the body. 


I V 




From the aorta the blood forced onwards at each beat of the heart by 
a new mass ejected from the ventricle, is distributed throughout the 
whole body with the exception of the lungs, and passes through the ca- 
pillary vessels into the veins. 

During violent bodily exertion, the motion of the blood in the capillary 
vessels must be interrupted in a great part of the body in consequence 
of the compression of vessels by the numerous muscles which are re- 
peatedly contracting. The more extended the operation of this cause of 
obstruction is, the more it resembles that interruption of the circulation 
which is produced by even slight obstructions in the lungs. Similar 
effects also are produced ; the column of blood offers a greater resistance 
than usual to the power of the heart ; the blood does not circulate freely 
and quickly enough through the lungs, and becomes accumulated there,, 

so that deficient aeration of the blood 

at the same time induced. 

Hence the labour of respiration during such great exertions, which is 
attributed, but less correctly, to an increased call for arterial blood on 
such occasions. The continued contraction of the muscles in cases 
where single limbs are kept for a long time in action, is also accompanied 
with accumulation of blood in these parts. In some animals which keep 
their limbs for a long time in continued action in climbing, nature has 
avoided the interruption of the circulation, — at least that produced by 
compression of the arteries, — by the immediate division of the arterial 
trunks of the extremities wholly or in part into a vast number of small 
anastomosing branches. Such a provision is seen in the bradypus, myr- 
mecophaga, manis, and stenops ; it occurs both in the vessels of the 
limbs, and in those of the tail, which is also used in climbing.* 

The smaller arteries in every organ of the body before they become 
capillary are connected by repeated anastomoses with each other, as 
may be seen in any finely injected membrane ; and many parts of the 
body receive blood by large arteries which arise from very different parts 
of the vascular system ; thus the brain is supplied from the internal ca- 
rotid and vertebral artery, and the communication between the epigastric, 
mammary, and intercostal arteries is well known ; similar anastomoses 

* Sir A. Carlisle, Philosoph. Trans. 1800. Vrolik, De peculiar! art. extrem. in nonnul- 
lis animalibus dispositione. Amsterd. 1826. Meckel, Vergleich. Anat. v. 339. Several 
other arterial plexuses are still enigmatical : for instance, the rete mirabile found in 
several mammalia, and which in the ruminantia and hog is formed from cerebral 
branches of the common carotid ; all its branches again uniting to form the cerebral 
carotid. Rapp (Meckel's Archiv. 1827) shows that in animals with a rete mirabile the 
vertebral artery does not go to the brain, and is either connected with the external 
carotid artery, as in the goat and calf, or, at the same time that it is connected with the 
rete mirabile, is also distributed to the cervical muscles, as is the case in the sheep. 
Similar net-works of arteries occur in the orbit of ruminantia, cats, and birds ac- 
cording to Rapp and Backow (Meckel's Archiv. 1829) ; and in these cases the arte- 
ries of the globe arise from the arterial plexus. In some birds a rete mirabile is situ- 
ated on the arteria tibialis antica. 









are met with in all parts of the body. The capillary system of all con- 
nected parts being continuous, all the vessels of the body, whether arte- 
ries or veins, are also connected through the medium of it. The capillary 
vessels of the whole body and the anastomoses of the arteries form in 
tnis manner an uninterrupted net-work, which receives blood from innu- 
merable arteries, and can be supplied with blood directly or indirectly 
rom different sources. If the vessel which usually conveys blood to a 
part is obstructed, new ways of supply are developed by the simple dila- 
tation of already existing communications without new vessels being 
formed. Thus is explained the phenomenon of collateral circulation, 
°r the restoration of the circulation through a part after obliteration of 
principal vessel. At first a number of anastomosing branches are 
dilated, and by degrees distinct vessels, of considerable size, are again 
developed from among them. In animals, the aorta abdominalis even 
^ay be tied without an absolutely fatal result. This operation has been 
Performed twice on man, but in each case death ensued. But all the 
°ther great arteries which are accessible in the human subject have been 
tied in cases where it was necessary, with success. There are, indeed, 
c ases recorded, proving, that when it takes place slowly, even the obli- 
teration of the aorta immediately below the origin of the arteries of the 
upper part of the body does not preclude the developement of a colla- 
teral circulation, the blood again finding its way circuitously to the part 
°f the aorta below the obliteration by dilatation of anastomoses between 
the internal mammary, first intercostal artery, and the intercostal branches 
from the aorta.* In a case of this kind, described by Reynaud,f the 
principal communications between the subclavian artery of each side and 

the part of the aorta below the obliteration were effected by anastomo- 
ses of the arteria cervicalis profunda, transversalis cervicis, and intercos- 
talis prima with the intercostal arteries of the thoracic aorta, and be- 


tween the subclavian and crural arteries by direct inosculation of the 
internal mammary and epigastric. 

The blood distributed through the arteries being impelled onwards by 
the new masses constantly ejected from the left ventricle, follows the 
course indicated through the vessels, and from the minute arteries is 
transmitted through the capillaries into the minute veins. This transit 
from arteries to veins can be observed by means of the microscope 
in many transparent parts ; so that its existence is not merely deduced 
from the course which the blood is known to take in the arteries and 
veins, but is an object of direct observation. 

The web of the frog's foot (fig. 14), the tail of young fishes, of the larvae 
of the salamander, frog, or toad, the mesentery of all mammalia, the wings 

* See the case observed by A. Meckel. Meckel's Archiv. 1827. 

t Froriep's Notiz. 537. 




Fig. 14. + 

of the bat, the germinal membrane of 
the egg of oviparous animals, are all 
well adapted for seeing the capillary 

The red corpuscules are distinctly 
seen flowing from the minute ramify- 
ing arteries into a net- work of vessels 
of nearly equal size throughout, and 
again collecting from this net-work 
into the radicles of the veins, which, 
by their successive reunion, form 
larger trunks. (See fig. 14.) 

In the finest capillary vessels the red particles flow one after another 
in a single series, which is frequently interrupted for a time : when they 
flow thus singly, they appear almost colourless ; when accumulated to- 
gether in greater number, they appear yellow ; and when in still larger 
quantity, they are yellowish red or red.J 

The blood during its passage through the capillary vessels becomes 
of a dark red colour. The motion of the blood in the veins is con- 
tinuous, not pulsatory as in the arteries. Those veins which are ex- 
posed to the pressure of muscles, have pouch-like valves which prevent 
the backward passage of the blood towards the capillaries, conse- 
quently, any pressure on the veins, instead of interrupting, favours the 
flow of the blood towards the heart. In the veins of parts protected 
from external pressure the valves do not exist. In the pulmonary 
veins Mayer has discovered incomplete valves. E. 
observed valves in the portal vein of the horse; they do not exist 

Weber has 

in man. 

c. Portal circulation. 

The blood of the spleen, intestinal canal, stomach, pancreas, and 

mesentery is not returned immediately to the vena cava; the veins 

* See the representation of the capillary vessels carrying blood, of the area vasculosa of 
the egg m Pander's Entwickelungs-geschichte des HUhnchens im Ei ; of young fishes in 
Doelhnger's Denkschrift der Akad. der Wissenschaft. zu Miinchen, Bd. vii. ; of the web 
of the frog's foot in Schultze's Lebens-process imBlute, Berlin, 1822, and in Marshall 
Hall on circulation, tab. iii. ; of different parts of frogs and mammalia, Kaltenbrunner, 
Exp. circa statum sanguin. et vas. in inflammatione, Monach, 1826 ; of the mesentery 
of the frog, Reichel, De sanguine ejusque motu, Lips. 1767, Marshall Hall, 1. c. t. iv. • 
of the tail of the stickleback, M. Hall, 1. c. t. i. ; of the embryos and larvae of fishes,' 
frogs, and salamanders, Baumgaertner iiber Nerven und Blut, Freiburg, 1 830. 

t Capillaries in the web of the frog's foot' magnified.— This is reduced from the 
representation given by Dr. A. Thomson in the Cyclopaedia of Anatomy. The en- 
graver has not preserved accurately the proportion between the size of the capillaries 
and the space in which they run ; the capillaries are somewhat too large. But the 
diagram shows the relation of the minute arteries and veins to the capillary net-work 
m the systemic circulation as compared with the pulmonic circulation. (See fig. 13.) 

On the circulation in the capillaries, see page 218. 





of these organs unite to form the vena porta?, by which their blood 



hepatic veins to the cam* Professor Retzius of Stockholm, however, 
has informed me that he has discovered in man some minute com- 
munications between the veins of the intestines and the branches of 


e vena cava. When 

ne injection of different colours, he found that the whole mesocolon 
and colon sinistrum were injected with both colours, and veins belong- 
ln g to the two systems at several places formed anastomoses. The 
veins of the colon and mesocolon, which belonged to the system of the 
y ena cava and entered the left renal vein, lay superficially, while those 
which belonged to the vena portae lay for the most part nearer the 
mucous membrane. The external surface of the duodenum also had 
received injection from the vena cava. M. Breschet too has filled the 
mferior mesenteric vein from branches of the inferior cava, and 
kchlemm has discovered distinct communications of the inferior me- 
senteric vein with branches of the inferior cava about the anus. From 

his fact the suggestion maybe drawn that in obstructions and con- 
gestions of blood, perhaps even in inflammations of the intestinal canal, 
abstractions of blood from about the anus will be of service. 

* he blood of the portal vein of all the vertebrata, — and the blood 
ot the afferent renal veins in fishes, amphibia, and reptiles, — has a 
second time to overcome the resistance offered by the minute canals 
of a capillary system, before it reaches the heart. I have discovered 
that in the larvae of the salamander, the circulation in the liver can be 

distinctly seen when viewed as an opaque object with a simple micro- 
scope^ The blood of the porta in its passage through the capillary 
vessels of the liver into the hepatic veins is seen to run in the in- 
terstices only of the acini, and the single particles of the blood can 
be as clearly distinguished as in transparent parts. ; 

The blood in the vena cava, as well as in all the venous canals of the 
hver, flows in jets, probably from the advance of the blood being checked 
hy each contraction of the right auricle, or of the inferior vena cava 
itself, which in frogs can be seen to contract periodically. There is no 
observable difference in the colour of the blood in the vena cava, the 
portae, and the hepatic veins. 


of the 

After this general description of the cir- 

culation of the blood, it remains for us to discuss the rate of its motion 
and the time in which it completes its entire circuit. The rate of 
the blood's motion in the vessels must not be judged of by the rapidity 
with which it flows from a vessel when divided. In the latter case, 

* See page 169. 

t Meckel's Archiv. 1828. See the drawing in my treatise, De gland, penit. struct, 
tab. x, fig. 10. 



the rate of motion is the result of the entire pressure to which the 
whole mass of blood is subjected in the vascular system, and which 
at the point of the incision in the vessel meets with no resistance. In 
the closed vessels, on the contrary, no portion of blood can be moved 
forwards but by impelling on the whole mass, -and by overcoming the 
resistance arising from friction in the smaller vessels. With respect 
to the time in which the circulation of a single portion of blood is 
completed, the following results have been deduced by Hering from 
eighteen experiments on horses. The time required for the passage of 
a solution of ferrocyanate of potash of different strengths, which is 
mixed with the blood, from one jugular vein (through the right side 
of the heart, the pulmonary circulation, the left cavities of the heart, 
and the general circulation) to the jugular vein of the opposite side, 
varies from twenty to twenty-five or thirty seconds ; from the jugular 
vein to the great saphena it is only twenty seconds, from the jugular 
vein to the masseteric artery between fifteen and thirty seconds, to 
the facial artery in one experiment between ten and fifteen seconds, 


another experiment between twenty and twenty-five seconds; 


its passage from the jugular vein to the metatarsal artery it occupied 
between twenty and thirty seconds, and in one instance more than 
forty seconds. The result was nearly the same whatever was the rate 
of the heart's action. These results do not, however, accord with the 
estimate of the time occupied by the circulation, which is deduced 
from the quantities of blood generally supposed to be contained in 
the body, and from the quantity which can be advanced at each beat 
of the heart. According to Wrisberg, a woman lost by a fatal flooding 
twenty-six pounds of blood, and in the beheading of a full-blooded 
woman twenty-four pounds of blood were collected. If we suppose 
two ounces of blood to be impelled forward at every beat of the heart 
it would require one hundred and sixty beats for the circulation of 
twenty pounds ; and for the circulation of ten pounds of blood, which 
Herbst* calculates to be the quantity of blood contained in the human 
body, eighty beats of the heart would be required. It may, therefore 
be admitted with more certainty that the circulation of the blood in 
man is completed in from eighty to two hundred and fourteen beats of 
the heart, or in from one to two minutes.f 

The time in which the blood performs its course from one side of the 
heart to the other, varies much according to the organ it has to tra- 
verse. The blood which circulates from the left ventricle, through the 
coronary vessels to the right side of the heart, requires a very far 
shorter time for the completion of its course than the blood which flows 
from the left side of the heart to the feet, and back again to the right 
side of the heart; so that the circulation from the left to the right 

* De sanguin. quanxit. Gottingen, 1822. 
t See Burdach's Physiologie, iv. p. 101 to 253. 








cavities of the heart forms a number of arches, varying in size ad infi- 
nitum^ the smallest of these arches being formed by the circulation 
through the coronary or nutritious vessels of the heart itself. The 
course of the blood from the right side of the heart, through the lungs, 
to the left, is shorter than most of the arches described by the systemic 
circulation, and in it the blood flows, cceter is paribus, much quicker than 
m most of the vessels which belong to the aortic circulation. Although 
the quantity of blood contained in the greater circulation of the body, 
°n account of its greater extent, is very far greater than the quantity 
within the lesser circulation, yet at any imaginary spot of the pulmonary 
artery, in a certain space of time, just as much blood passes as at any 
^agined point in the aorta ; for, although in the capillaries the circula- 
tion is subject to great variation, in the main trunks of the closed circuit 
n o more blood can leave one point than finds place at another point. If, 
therefore, we suppose the capillary vessels between arteries and veins to 
be equally large in the lungs and the rest of the body, a far greater num- 
ber of them must be included in the same space in the lungs than in 
other parts of the body. This is found by observation to be the case, for 
m the lungs of frogs the interspaces between the capillaries are scarcely 
larger, in man even smaller perhaps, than the diameter of the capillary 


vessels themselves* This 

Marshall Hall, Prevost and Dumas, Weber (in the human subject) 

more recently by myself. 

Lastly, it is to be remarked, that the rapidity of the motion of the 
blood in the small branches must necessarily be less than in the trunks 
generally, if, as seems to be the case, the aggregate area of the branches 
of a stem is larger than the area of the stem itself, although this must 
not be regarded as strictly proved. If, however, we imagine all the small 
vessels of any single organ united into one trunk, and the blood to flow 
in a circular course from the artery into this trunk, and thence through 
the vein into the artery again, thus forming a closed circle, although the 
movement of the single particles of the blood will be more rapid in those 
parts of the circle where the tube is narrow, and slower, where the tube 
is wider, still within a given time the same volume of blood must pass 
each and every point of the circle. 

* * 




The heart, like other muscular organs, contracts when irritated me- 
chanically, or by galvanism. Soemmering, Behrends, and Bichdt denied 
the influence of galvanism on the heart, but I have frequently repeated 
Humboldt's and Fowler's experiments, and have obtained the same re- 
sults as they did. In both frogs and dogs, in which the heart had ceased 
to act, I have re- excited its contractions by means of a single pair of 

* See page 170« 



-•-' *.w. 



plates, or a weak galvanic pile. But the heart, with most other organs 
which are endued with involuntary motion only, such as the intestinal 
canal, is distinguished from voluntary muscles, by the irritation exciting 
in it not a single contraction, but a succession of periodic contractions. 
The heart being thus, like all muscles, excited to action by a stimulus, 
it is very natural to conclude that the blood contained in its cavities sup- 
plies the stimulus during life ; and this supposition is strengthened by 
the circumstance of the heart's action becoming more feeble in propor- 
tion as the quantity of blood it contains is diminished. 

To explain why the contractions are rhythmic, it has been said that 
the same act — the systole — by which the heart expels its stimulus — the 
blood — in one direction, causes its cavities to be again filled with blood 
from the veins. In the same way the alternation of the contractions of 
the auricles and ventricles may be explained, since the one cavity by its 
contraction gives rise to the filling of the other. But however neces- 
sary a certain quantity of blood and a certain distension of the cavities 
of the heart may be for the preservation of its action, and however cer- 
tain the effect of every mechanical dilatation of the heart from within 
may be in exciting its contraction, yet the stimulus of the blood in its 
cavities cannot be the primary cause of the contractions of the heart 
for the heart still continues to contract, though feebly, when emptied of 
its blood. The regular succession of the heart's contractions may be 
explained in another way. The heart, at each systole, expels the blood 
from its nutritive vessels, which, when the contraction ceases, are again 
re-filled by the agency of the elastic coats of the arteries, which exert 


a constant pressure on the blood contained in them. The re-filling of 
the minute vessels of the heart with blood during each diastole may be 
supposed to become the cause of a fresh contraction. This hypothesis, 
however, is refuted by the same fact as the former ; for the heart, parti- 
cularly that of amphibia and fishes, continues to contract regularly — the 
auricle and ventricle in the same succession — when it is removed from 
the body and emptied of its blood; in amphibia, indeed, the action con- 
tinues for hours. This might, however, be explained by attributing it 

to the stimulus of the atmosphere, which, although its action is con- 
stant, may nevertheless excite periodic contractions.* But the action 
continues in a vacuum, and an external cause like the air does not ex- 
plain the regular succession of the ventricular contractions after those 
of the auricles. The cause, then, must be in some way connected with 
the organisation of the heart, and with the constant mutual action which 
is going on between the blood in the capillaries, or the cardiac nerves, 
with the texture of the heart; and whether the cause be constant in 
its action or periodic, the rhythmic contractions of the heart are equally 
explicable. The nature of the cause, however, cannot be determined in 
the present state of our knowledge. 


* In accordance with the law of excitability stated at page 57. 



Influence of the 


, - * — When the chemi- 

cal changes effected in the blood in the lungs are interrupted,— whether 
jt be from the respiratory movements being checked, in consequence of 
esion of the nerves on which they depend,_whether it be from mecha- 
nical impediments to the movements, or from the inhalation of irrespira- 
bl e gases,— the vital action of all the organs of the body is depressed, 
and, in the higher animals, is indeed soon annihilated. It is true, the 
Wood no longer arterialised, continues for a time, as Bichat and Emmert 
nave shown,* to move in the arteries ; and the heart, after the apparent 
death of the body, generally continues to beat slowly and feebly even in 
warm-blooded animals during more than half an hour ; nevertheless, in- 
terruption of respiration enfeebles its action to such a degree, that the 
circulation very soon ceases ; while, on the other hand, if, (after the xz- 
spiratory movements have been interrupted by injuries of the encepha- 
°n, but particularly of the medulla oblongata, or by poisoning,) artificial 
respxration be performed, the circulation may be maintained for a much 
"~ger period, whatever be the animal on which the experiment is insti- 

In a dog beheaded after tying the cervical vessels, and in which 
artificial respiration was kept up, Brodie saw the heart continue to beat 
0r two hours and a half, in which space of time there were thirty-five 
pulsations ; and, in another dog, an hour and a half, during which period 




on the heart's action seems to be greater than that of the nervous sys- 
tem. In cold-blooded animals, however, this influence of the respiration, 
or of arterialised blood, on the heart is much less evident; for frogs 
the lungs of which I had tied and removed, have lived thirty hours 
afterwards, the action of the heart still continuing; while, after de- 
struction of the brain and spinal marrow in these animals, the action of 
the heart ceases much sooner, namely, in six hours : consequently, either 
the function of respiration in frogs can, after removal of the lungs, be 
supplied by the skin, or the brain and spinal marrow are in these ani- 
mals much more necessary to the maintenance of the heart's action than 
respiration. The latter is most probably the more correct explanation, 
for when they can breathe neither by the lungs nor by the skin, namely, 
when they are immersed in pure hydrogen, frogs live more than twelve 
hours, as I have myself witnessed. The final suspension of the heart's 
action, in cases where respiration is suspended, may indeed depend 
chiefly on the change which ensues in the nervous system when it no 
longer receives red blood. 

The disturbance of the circulation, after interruption of the respira- 
tion in the higher animals, is certainly not produced by the collapse of 
the lungs ; for, although these organs in the collapsed state might offer 
some impediment to the passage of the blood, the motion of the blood 

* Reil's Archiv. v. p. 401. 

f Rett's Archiv. xii. p. 140. 





in the arteries, as Bichat and Emmert showed, continues in such cases 
for a certain time undisturbed. 

Dr. Goodwin attributed the depression of the circulatory powers, after 
interruption of the respiration in the higher animals, to the circum- 
stance of the left ventricle ceasing to receive arterial blood, and supposed 
that the influence of this kind of blood was indispensably necessary to 
the action of the left side of the heart. To this Bichat replied, that in 
animals of which the respiration is suspended, the dark blood coming 
from the lungs to the heart does not cause the immediate cessation of the 
contractions* This and other arguments adduced by Bichat* are not 
conclusive. It is not, however, at all probable that each side of the 
heart has a specific irritability for different kinds of blood; for in the 
foetus, in which the auricles communicate by the foramen ovale, and in 
which there is no pulmonary respiration, but only some peculiar change 
effected in the blood in its passage through the placenta, both sides of 
the heart receive the same kind of blood. If the immediate action of 
bright red blood on the heart is really necessary to the maintenance of 
its action, Bichat's explanation is much the more probable. He sup- 
poses that interruption of the respiration deprives the heart of its irri- 
tability, by preventing the supply of arterialised blood to the muscular 
fibres by the coronary arteries, which now carry dark venous blood. 
But although it appears certain that arterial blood does exert an influence 
on the heart's action, yet the relative degree in which this influence and 
that of the nerves are necessary cannot be estimated, for all disturbances 
of the respiration produce corresponding disturbance in the action of 
the nervous system. 

2. Influence of the nerves on the heart's action. — The influence of the 
passions, and other affections of the nervous system, on the heart's action, 
is matter of constant observation. All sudden passions at first disturb 
and then accelerate its action ; the contractions being much more vigorous 
and frequent under the influence of the exciting passions, while they are 
rendered feeble, at the same time that they are accelerated by the de- 
pressing passions. 

Nevertheless, some persons have denied the dependence of the heart 
on nervous influence. Thus Haller denied it, because the heart conti- 
nues to contract when removed from the body, and because irritation of 
the cardiac nerves does not produce those convulsive actions which irri- 
tation of the nerves of other muscles gives rise to. 

The first researches on this subject are those of Soemmering and 
Behrends on the cardiac nerves, in 1792, which tended to prove that the 
substance of the heart receives no nerves, and that all the fibres of the 
cardiac nerves in the heart are distributed to the coats of the cardiac 
vessels. This seemed to confirm Haller's doctrine of the contractility of 
the muscles, namely, that this power is inherent in the muscles them- 

* Rech. sur la vie et la mort. 







selves, and not dependent on the influence of the nerves, and that the 
nerves excite contractions in the muscles in the same way as external 
stimuli, whether mechanical, electrical, or chemical ; and it would follow, 
tnat the heart not being endowed with the nervous stimulus, is stimu- 
lated to motion by the blood itself. The experiments of Soemmering and 
ehrends, to show that galvanism produces no contraction of the heart, 
while it has this effect in all muscles provided with nerves, seemed to 
confirm this view still more strongly. 

But Scarpa has demonstrated that the cardiac nerves are really dis- 
puted in great abundance to the muscular substance of the heart, 
umboldt, Pfaff, Fowler, and Wedemeyer have succeeded in producing 
contractions of the heart by means of galvanism ; and I have repeated 
their experiments with success in frogs as well as in mammalia. Hum- 
ol dt* states that by galvanising the cardiac nerves he has produced 
contractions of the heart. The nerves may, as Burdach rightly remarks, 
act as moist conductors when one wire of the battery is applied to them,' 
e other to the heart ; Burdach,f however, actually saw the contrac- 
ts of the heart of a dead rabbit become stronger when he applied 
oth wires of the pile to the cervical portion of the sympathetic nerves, 
° r to the inferior cervical ganglion. Such experiments on the motor 
Power of the nerves are not conclusive unless the wires are applied to 
ie nerves alone, and unless the galvanic action is very weak. Strong dis- 
c larges may be transmitted through nerves acting as moist conductors 
merely, even to the heart itself. For this reason the experiments of 
Burdach, in which he re-accelerated the action of the heart of a dead 
rabbit, after it had begun to fail, by touching the sympathetic nerves 

with caustic potash or ammonia, are the more interesting ; and particu- 
larly so, since, in a dead rabbit, painful impressions can no longer have 
any effect in changing the action of the heart. I did not, however, my- 
self succeed in obtaining the same result in repeating this experiment 
A he experiments which Brachet+ and others have instituted on livino- 
animals, for the purpose of determining the irritability of the nerves° 
are of no value with regard to the heart, the heart's action being so much 
affected by painful impressions. 

Another phenomenon which distinguishes the heart from other 
muscles is the persistence of its rhythmic contractions in their regular 
order in the different cavities, even when removed from the body and 
emptied of its blood. This cannot be explained otherwise than by 
supposing the heart under these circumstances to retain with its nerves 
some specific nervous influence. The influence of the nerves, therefore 
seems to be the cause of its contractions ; and this seems to be con- 
firmed by the great effect which irritations of the brain and spinal 

* Ueber die gereizte Muskel- und Nervenfaser, i. 342. 

$ Recherches sur le systeme ganglionaire. 

t Physiol, iv. 464. 




marrow, and passions of the mind, have in modifying the action of 
the heart. If it were possible to destroy the vital function of the 
nerves, without at the same time depriving the muscles of their power of 
contraction, this question might be set at rest ; but unfortunately the 
narcotic agents, which, when applied to the nerves, take from them 
their property of exciting — when irritated — contractions in the muscles 
to which they are distributed, render the muscles incapable of exercising 
their contractile power when the nerves are irritated. Opium applied 
to the heart of a frog soon puts a stop to its motion ; when I em- 
ployed the watery solution of opium which Humboldt used, I did 
not succeed. Although the dependence of the heart's action on nervous 
influence cannot be demonstrated in this manner, it is nevertheless 
evident that the nerves have a great share in its action, from the 
sudden disturbance and cessation of the rhythmic movements when 
the whole spinal marrow is suddenly destroyed. 

Influence of 

action. — The 

inquiry respecting the part of the nervous system from whence this 
influence on the heart is derived, whether immediately from the cardiac 
nerves and sympathetic system, or through the medium of these from 
the spinal marrow and brain, was originated by Bichat. Before 
entering into this inquiry, it will be necessary to give a sketch of 
the principal divisions of the nervous system. The functions of the 
two systems of nerves were more exactly defined by Bichat. The 
nerves arising from the brain and spinal marrow have for the most 
part the power of exciting voluntary motion in the muscles to which 
they are distributed, but lose this power when their connection with 
the nervous centres is cut off; and the nerves arising from the spinal 
marrow are also deprived of the power of communicating volition when 
their connection with the brain is interrupted by injury of the spinal 
marrow. Nevertheless one of these nerves- thus cut off from its source 
of volition — the nervous centres, — still retains for a time the power of 
exciting involuntary contractions of muscles when it is irritated me- 
chanically or by galvanism. 

The parts to which the branches of the sympathetic nerve are dis- 
tributed, for example, the heart, intestines, and uterus, are endowed by 
them with involuntary motion only. The sympathetic nerve is connected 
with the brain and spinal marrow indirectly only, through the medium 
of the cerebro-spinal nerves. Bichat called the cerebro- spinal nerves 
"the nerves of animal life," the sympathetic nerves he styled the 
" nerves of organic life," and ascribed to the latter a certain independ- 
ence of the brain and spinal marrow, regarding the ganglia and plexuses 
as their nervous centres. Recently a discovery has been made, which 
in the history of physiology ranks second only to the discovery of the 
circulation of the blood; it is, that the nerves which arise by an anterior 










and posterior root from the spinal cord derive their power of exciting con- 


tractions in the muscles from the anterior root, and their power of sensa- 


tion from the posterior root. This discovery is due to Bell. I have 
since proved that mechanical and galvanic stimuli applied to the posterior 
root have no power of exciting contraction in the muscles to which the 
spinal nerves are distributed.* Scarpa t not long since endeavoured to 
show that the connection of the sympathetic nerve in the chest with the 
commencement of the spinal nerves impl cates the posterior roots only of 
the latter nerves, and not their anterior roots ; and consequently that 
the sympathetic nerve can neither be intended to communicate motor 
power to the heart from the spinal marrow, nor possess motor power 
itself. The researches of Wutzer and myself, as well as those of 
Retzius and Meyer, have shown, however, that Scarpa is incorrect, 
and that the rami communicantes inter nervum sympatheticum et nervos 
spinales receive their fibres from the anterior motor, as well as from 
the posterior sensitive roots of the spinal nerves^ The principal ex- 
periments made with a view to elucidate the influence of the spinal 
c ord and brain on the motions of the heart are those of Legallois, 
Philip, Treviranus, Nasse, Wedemeyer, Clift, and Flourens. 

The new facts brought forward by Legallois § to prove that the cause 
of the heart's action resides in the spinal cord alone, may be reduced 
to the following heads : When the cervical portion of the spinal cord 
and medulla oblongata of an animal is destroyed, respiration ceases on 
account of the destruction of that part of the nervous centres from 
which the respiratory nerves arise ; the action of the heart still con- 
tinues, though too feebly to maintain the circulation, and the strength 
of the heart's contractions necessary for this purpose cannot be re- 
excited by artificial respiration. If the spinal cord is destroyed in 
successive portions at distinct intervals, the heart's action is supported 
longer than if it were suddenly destroyed. The circulation of the 
blood is also interrupted by the destruction of the inferior part of the 
spinal cord by thrusting a wire up the canal. In this case also it 
not restored by artificial respiration. From these experiments 
Legallois concluded that the nervous power of the heart was derived 
from the spinal cord, and not from any particular portion of it, but 
from the whole cord. Legallois then reasoned that if this was true, 
after destruction of a part of the spinal marrow, the nervous influence 
°f the uninjured part would no longer be sufficient to enable the 
heart to put in motion the whole mass of the blood, but that it would 



See Book iii . 

+ Scarpa, De gangliis nervorum, deque origine et essentia nerv. intercostalis ; 
H. Weber. Annal. univers. d. medicina. Magg. e. Giugn, 1831. 
t See Meckel's Archiv. 1831, i. p. 85 u. 260. 
§ Exp. sur le principe de la vie. Paris, 1812. 





certainly be sufficient, if artificial breathing was kept up, to force the 
blood through a part of the vascular system. Thus Legallois came 
to the conclusion that if, after partial destruction of the spinal marrow, 
the course of the blood through the vascular system was limited by 
tying certain vessels, the circulation would still be maintained in the 
course thus circumscribed; and that by placing the ligature nearer 
the heart, so as to diminish still more the extent of the circulation, 
a still larger part of the spinal cord might be destroyed without the 
circulation being interrupted. Legallois tied the aorta in rabbits in the 
lumbar region, and destroyed the lumbar portion of the spinal cord. 
In other cases, after decapitating the animal, he tied the carotids and 
jugular veins, and then destroyed the cervical portion of the cord, keeping 
up artificial respiration ; and in still more barbarous experiments he re- 
moved the entire posterior half of the body after tying the great vessels. 
In all these cases the circulation between the heart and the ligatures was 
carried on for a longer or shorter time, and in many cases, according to 
Legallois' account, for more than three quarters of an hour. 

The inference which Legallois deduced from his experiments was, 
that the sympathetic is not an independent nerve ; that it is not merely 
connected with the spinal cord, but that it arises from it, and that it is 
the peculiar character of this nerve to place all parts to which it is dis- 
tributed under the motor influence of the whole spinal cord. The com- 
mittee appointed to examine Legallois' statement believed that these ex- 
periments solved all the difficulties which had before existed respecting 
the motion of the heart,— for instance, the influence of the passions on 
the heart, its independence of the will, and the persistence of the circu- 
lation up to the time of birth in anencephalous or acephalous monsters. 

'" * Philip,* however, has shown that the experiments of 
Legallois have not explained the whole relation between the brain, 
spinal cord, and sympathetic nerves. When an animal is deprived 
of voluntary motion and sensation by a blow on the occiput, respi- 
ration ceases, but the heart's action still continues, and may be sup- 
ported for a long time by keeping up artificial respiration. If the 
spinal cord and brain are now wholly removed by the knife, the 
heart nevertheless still continues to beat, though feebly ; and 'even 
when the spinal marrow and brain are destroyed by a hot wire, the 
heart's action generally continues. Hence 

conclusion the very opposite of that of Legalloi^-namdy" that "the 
heart's action is essentially independent of the brain and spinal mar- 
row ; although, as his experiments seem to show, the influence of both 
brain and spinal marrow has a great share in the sympathetic affec- 
tions of the sympathetic nerve and heart. 

Dr. Philip, having laid bare the spinal marrow and brain, and dropped 




Inquiry into the laws of the vital functions. 



some alcohol upon them, the motion of the heart was increased ; and in 
the most marked degree when the spirit was applied to the cervical 
portion of the spinal marrow, most feebly when it was applied to the 
lumbar portion. Opium and decoction of tobacco had the same effect. 
The stimulant effect of the opium and tobacco was evidenced before the 
narcotic influence; the motions, from being accelerated, gradually became 


er. These stimulants still exerted their influence through the me- 

dium of the brain and spinal cord on the viscera when their application 
0* this manner had ceased to have any effect on the voluntary muscles. 
Dr. Marshall Hall however states, that in his experiments neither opium 
nor alcohol produced acceleration of the circulation; and that poisoning 
with opium, at the same time that it produced tetanus, put a stop to the 



of its nerves stands in relation with all parts of the brain and spinal 
marrow, — while individual voluntary motions are connected only with 
individual parts of the brain and spinal cord. Wilson Philip has also 
observed that the influence which destruction of the brain and spinal 


c ord exerts upon the sympathetic nerve, and the viscera to which it is 
distributed, depends very much on the mode in which the operation is 
performed. If the brain is destroyed by cutting out single parts, if the 
whole brain is removed, or if the spinal cord is slowly destroyed by a 
hot stilet, the heart continues to beat for a long time, although more 
feebly than natural ; but if the destruction is performed quickly, and 
as it were by crushing, the action of the heart is immediately stopped. 
Thus, when the brain of a living frog was crushed by the blow of a 
hammer, the heart immediately performed a few quick and feeble con- 
tractions, and then lay quite motionless for half a minute, and its action 
then returned, but feebly. The spinal marrow was now quickly destroyed 
with violence, and the motion was again interrupted for a time ; the 
contractile power however was gradually recovered. Clift saw the heart 
of a carp continue to beat eleven hours after destruction of the spinal 


The conclusion that Flourens deduced from his experiments on fishes 
is, that the action of the heart depends solely on the respiration, and that 
it ceases when the respiratory movements are put an end to by injury of 
the portion of the nervous centre on which these motions depend ; and 
that in fishes, the respiratory movements of which depend on the me- 
dulla oblongata only, respiration, and consequently the circulation, con- 
tinues after injury of the spinal cord- Dr\ 
seen the circulation in fishes endure for a very long time after destruc- 
tion of the medulla oblongata. He nevertheless allows that the heart is 
in some measure dependent on the spinal cord and brain.f 

* Essay on the circulation. 

tOn this subject consult Treviranus, Biol. iv. 644. Clift, Phil. Trans. 1815, 

o 2 







If the experiments of Legallois, Philip, and others, are taken into con- 
sideration, together with the facts already known, namely, that the heart 
when removed from the body still continues to beat for a long time, par. 
ticularly the heart of reptiles, amphibia, and fishes ; that depressing affec- 
tions of the nervous system weaken the force of the heart's action ; and 
that, with nervous fainting, feebleness of the circulation is combined ; 
the following results may be deduced from them :— 1. That the brain 
and spinal marrow have a great influence on the motion of the heart ; 
that its movements may, through their agency, be accelerated or re- 
tarded, depressed or invigorated. 2. That the heart's action, however, 
still continues for a certain time after simple removal of the spinal cord 
and brain from the body. Flourens observed that pulsation of the ca- 
rotids continues for more than an hour in rabbits under these circum- 
stances, artificial respiration being kept up. That the heart's motions, 
however, are much feebler, and the circulation is not maintained perfectly, 
for any long period. 3. That even when the heart is cut from the body, 
and consequently separated from the greatest part of the sympathetic 
nerve, its contractions still continue for a short space of time. 

The heart is not so much dependent on the influence of the brain and 
spinal marrow that the removal of these organs immediately annihilates 
its power of motion. The cardiac nerves, under such circumstances, still 
retain a portion of the motor influence, and even the small part of these 
nerves which can be contained in a heart cut from the body still retains 
sufficient nervous power to enable the organ to continue its motions for 
a short time. But the brain and spinal marrow must nevertheless be 
regarded as a principal source of the nervous influence; for their de- 
struction enfeebles the heart's action to such a degree, that, although it 
is continued for a considerable time, its force is not sufficient to keep up 
the circulation. The only mode of ascertaining the degree in which the 
heart is subject to this influence is that adopted by Nasse. He mea- 
sured the height of a stream of blood which issued from a divided artery 
in the normal state, then destroyed the spinal cord or single parts of it, 
and now found that the height of the stream of blood had in a few minutes 
diminished, and in a degree proportioned to the injury. 

The sympathetic nerve, however, is certainly not dependent on the 
brain and spinal marrow in the same degree as the cerebrospinal nerves 
This is evident from the single fact, that in fishes the contractions of the' 
heart continue for the space of half a day after destruction of the brain 
and spinal marrow. 

Wedemeyer, Physiol. Untersuch. iiber das Nervensystem und die Respiration, Han- 
nov. 1817. Nasse, in Horn's Archiv. 1817, 189. Flourens, Versuche iiber die 
Eigenschaften und Verrichtungen des Nervensystems ; Leipz. 1824. Nasse, Untersuch 
zur Lebensnaturlehre ; Halle, 1818; which contains an elaborate review of the expe- 
riments of Legallois and a luminous statement of the whole subject. See also Lund" 
Physiol. Resultate der Vivisect, neuerer Zeit. Kopenh. 1825, 162. ' 




Circulation in acephalous monsters. — In monsters in which brain and 
spinal cord are wanting, the circulation seems to be still more indepen- 
dent of the nervous centres, but the anatomy of these monsters is not 
at present known with sufficient accuracy for any conclusion with regard 
to the present question to be drawn from them. In hemicephalous mon- 
sters the brain has mostly been destroyed by hydrocephalus, and the 
same disease may also destroy the spinal marrow. 

In acephalous monsters the heart also is generally, but not always 
absent; and the vascular system consists generally onty of two systems 
°f vessels connected, not by their trunks, but only by their capillaries, 
the umbilical vessels being branches of these trunks.* Winslow's case 
is the only one in which the umbilical vein was continuous with the ar- 
terial trunk, resembling that condition of the embryo in which the heart 
is merely the part at which the venous trunk makes a bend and is con- 
tinuous with the arterial. It cannot be admitted that in the acephalous 
monsters without heart there had been no circulation. One point of 
the arterial stem may have had contractile power, and have thus supplied 
the place of the heart, which in the embryo at its earliest period had the 
form of a vessel. If a circulation really did exist, it could continue 
any length of time ; and indeed since, in some of these cases, the 
spinal cord also was deficient, these monsters seem to prove that the 
circulation of the blood in their double system of vessels can be carried 
on without the aid of the brain and spinal cord, and consequently that 
the contractile parts of viscera, which are supplied by the sympathetic 
nerve, may be completely independent of the brain and spinal cord. 
Brachetf has collected all the accounts of acephalous monsters in which 
the spinal marrow also was deficient.^ The case mentioned by Ruysch,§ 
in which an inferior extremity was connected with the placenta of a well- 


formed foetus, is particularly remarkable. Emmert || has described a pro- 
duct of conception which consisted almost entirely of an extremity hung 
to an umbilical cord, and contained vessels, arteries, and veins, and a 
short stump of spinal marrow.^ There is no difficulty in explaining the 
circulation of the monster without heart and spinal marrow, in which its 
vessels are merely branches of the vessels of the umbilical cord of another 
foetus, as was the case in the monster described by Rudolphi,** which 
consisted of a head only, and in the case which I observed myself of a 
head which was connected by arteries and veins with the umbilical vessels 
°f a completely formed child.ff See also the case of the rudimentary 

Tiedemann, Anat. d. Kopflos. Missgeburt ; Lanshut, 1813. f lj0C - cit * 

t See also Meckel, Pathol. Anat. i. Elben, De acephalis j Berol. 1821. 
§ Thesaur. Anat. ix. p. 17- tab. i. fig. 2. || Meek. Archiv. vi. 

IT A similar case is described by Hayn, Monstri unicum pedem referentis descrip- 

tio anatomica. Berol. 1824. 
** Abhandl. d, Akad. zu Berlin, 1816. 

ft M tiller's Archiv. 1834, 179. 







monster, of which Gurlt* has given a representation. Rudolphi, to 
explain the circulation in other monsters without heart, says that the 
blood of the mother passes to the foetus through the umbilical vein, 
which is distributed through it like an artery, and that the arteries of 
the fcetus bring back the blood to the umbilicus and placenta.t This 
explanation, however, is very inconsiderate, for the vessels of the fcetus 
or placenta do not really communicate with those of the mother. 

Influence of the sympathetic nerve on the hearts action, 

strangely asserted, without any grounds, that the sympathetic nerves of 
the fcetus is first formed. The very meritorious Rolando has also de- 
served censure in declaring the first traces of the vertebrse, at the side 
of the spinal cord in birds, to be ganglia of the sympathetic nerve. 

Not only brain and spinal cord, but all the organs in their state of vital 
action, and consequently the whole system, react upon the sympathetic 
nerve through the medium of the nervous fibrils accompanying the blood- 
vessels, and excite its peculiar motor power. The constant source of 
the heart's contractility is, therefore, primo loco the motor power of the 
sympathetic nerve. But the maintenance of this power, and its excite- 
ment, is dependent not only on the brain and spinal cord, but probably on 
the vital stimulus transmitted by all the organs of the body through the 
medium of the nerves accompanying the vessels to the central portions 
of the sympathetic. Hence it is that a local disease is able to excite 
general feeling of illness in the whole body, and a very violent local dis- 
ease can affect the heart's action and the pulse. 

The modifications which the minute radicles of the sympathetic in any 
part undergo from violent local disease, and the reaction of these modi- 
fications on the central parts of the sympathetic system,— the cardiac 
nerves and the plexuses,— as well as on the brain and spinal cord, seem 
to have a main share in the phenomena which we call fever. 

No observations have at present been made on the influence of parti- 
cular portions, or regions of the sympathetic nerve, on the action of the 

The only facts bearing on this point are those ascertained by 
Pommer,! who found in fifteen experiments that the division of the sym 
pathetic in the neck had generally no important consequences. Several 
cerebral nerves being intimately connected with the sympathetic nerve 
and the nervus vagus in particular having an essential share in the com- 
position of the cardiac plexus, it would be very desirable to know, also, 
what influence these nerves exert on the heart's action. Emmert ob- 
served that division of the nervus vagus produces but very slight distur- 
bance in the circulation ; and Bichat and Legallois with justice remark, 
that the effects produced, which are by no means considerable, on the 

* Pathol. Anat. 2 Bd. tab. 16, fig. 1—4. 



Wissensch. i. 226. 

t Beitrage zur Natur-und Heilkunde : Heilbronn, 1831. 







1 > 









heart's beat, cannot with certainty be ascribed to the division of the 
nerve, since the mere pain and fear produced by the operation might 
give rise to them. 




Of the Arteries. 

The middle coat of arteries is composed of flat fibres and bundles of 
fibres, which surround the vessel in a circular direction, are not muscular 

in their nature, and do not exist in veins. It is to these fibres that the 

arteries owe their great elasticity, or the property of contracting to their 
original diameter after being distended. Their elasticity is a physical 
property, and is preserved for a considerable period after death, — in fact, 
until decomposition ensues. It is by virtue of the same fibrous coat 
that arteries, even when empty, do not collapse, but remain of a cylin- 
drical form, and that they are enabled to adapt themselves to very dif- 
ferent degrees of fulness. 

Cause of the pulse. — 'By each contraction of the ventricle afresh por- 
tion of blood is propelled into the aorta, and the rapidity and force of the 
circulation in the arteries is increased. The periodic acceleration of the 
motion of the blood in the arteries thus produced was proved by Dr. 
Hales : having introduced a tube into an artery, he observed that the 
blood rose one inch, or even several inches, in the tube at every beat of 
the heart. The blood not being able to escape from the arteries as quickly 
as it is forced into them by the ventricle, on account of the resistance it 
experiences in the capillaries, necessarily exerts a pressure on the elastic 
coats, and thus gives rise to what is called the pulse. The pulse being 
dependent on the contraction of the ventricle, is, in general, synchronous 
with it. In consequence of the pressure exerted by the blood, the coats 
of the arteries become extended at each systole of the heart, while, 
during the diastole, they recover their former state by virtue of their 
elasticity. The extension of their coats takes place both in length and 
ln the direction of their diameter, but the elongation is by far the most 
considerable. A necessary consequence of their elongation is, that they 
change their position and become curved ; but they straighten themselves 
and recover their original situation when the ventricular contraction has 
ceased. Rudolphi, Laennec, Arthaud, Parry, and Doellinger, denied 
that the arteries undergo any dilatation. We have, on the other hand, 

Walther, Tiedemann, Meckel 



of the pulmonary artery in the lung of the frog the dilatation, as well as 
the incurvation of the vessel, can be seen with the greatest distinctness. 
I have also witnessed it in the abdominal aorta of the frog, and once 






quite satisfactorily in the aorta of the rabbit. The dilatation must, how- 
ever, be less considerable than the elongation, for it is not always observed 
with distinctness.* Poiseuille,t indeed, has measured the degree of this 
dilatation of the arteries. His experiment was ingenious ; he laid bare 
the common carotid of a living horse for the space of three decimeters, or 
about twelve inches, and passed beneath it a tube of white metal, open 
at one side, which he afterwards closed by means of a narrower portion, 
so as to complete the tube ; he then stopped the ends with wax and fat, 
and filled the interior of the tube around the artery with water, by means 
of a glass tube which was connected with the metallic tube. At every 
pulsation the water rose 70 millimeters J in the glass tube, whose dia- 
meter was 3 millimeters, and fell again the same distance during each 
pause. The included portion of artery measured in length 235 milli- 
meters, and contained the space of 2,106 millimeters square; now, since 
at every beat of the heart it increased 3x70=210 millimeters square 
in calibre, it follows that it was dilated about J T of its capacity. 

The pulse in different arteries. — It was asserted by Bichat, and is com- 
monly admitted, that the pulse is synchronous in all the arteries of the 
body, whatever their distance from the heart. 

Weitbrecht, Liscovius, and E. H. Weber § have shown, however that 
this is not the case. The pulsation of the arteries near the heart is syn- 
chronous with the contraction of the ventricle. But at a greater dis- 
tance from the heart the arterial pulse ceases to be perfectly synchronous 
with the heart's impulse, the interval varying, according to Weber, from 
one-sixth to one-seventh of a second. Thus the pulse of the radial 
artery even is somewhat later than that of the common carotid. The 
pulse of the facial, at about the same distance from the heart, is isochro- 

nous with the pulse in the axillary artery ; while the pulse is felt some- 

what later in the metatarsal artery on the dorsum of the foot, than 
in the facial artery and common carotid. Weber || has explained 
the cause of this difference. If the blood circulated in perfectly solid 
tubes, whose walls admitted of no extension, the impulse of the blood 
driven by the ventricle into the arteries, would be communicated even to 
the end of the column of blood, with the same rapidity with which sound 
is propagated through this fluid,— much quicker, namely, than in atmo- 
spheric air ; the pressure of the blood would be transmitted to the finest 
extremities of the arteries, with no perceptible loss of time. But, in 
consequence of the arteries admitting of some extension, particularly in 
length, the impulse given to the blood by the heart distends first merely 

* See the Observations of E. H. Weber, Hildebrandt's Anat. t. iii. p. 67 
t Magendie's Journal, t. ix. p. 44. 
[A millimeter equals 03937 of an English inch.] 


§ In the Treatise De pulsu non in omnibus arteriis plane synchronico. 
j| Adnotat. Anatom, 






the arteries nearest to the heart. These, by their elasticity, again con- 
tract, and thus cause the distension of the next portion of the arterial 
system, which also, in its turn, by contracting, forces the blood into the 
next portions, and so on ; so that a certain interval of time, although 
a very short one, elapses before this undulation, resulting from the suc- 
cessive compression of the blood, and the dilatation and contraction of 
the arteries, reaches the most distant branches of the arterial system. 
Weber compares this action to the propagation of the undulations 
that are produced by a stone thrown into a lake ; in which case, like- 
wise, the undulations are not transmitted with the rapidity of sound. 
■The rapidity of the transmission of undulations in water twenty-three 


M. Weber 

an d a half Paris feet in a second. Bichat confounded the motion of 
the undulations in a river with the movement of the water itself, and 
believed the pulse to be produced, not by the progressive undulations, 
but by the impulse communicated at the same moment to all the ar- 
terial blood. The motion of undulations always depends on the oscilla- 
tions transmitted from the point where the impulse is applied, and never 
°n the progressive motion of the fluid itself. The water of an undula- 
tion rises and falls, but remains in the same place, while the undulation 
and oscillation is propagated onwards in successive portions of water. 
Thus it is that very light bodies on the surface of undulations rise and 
fall, it is true, but remain in the same spot, while the undulation is pro- 

For the transmission of the pulse a continuous column of blood is re- 
quired ; if the arteries were empty at different points, the transmission 
of the pulse, as Weber remarks, would be much slower, or quite inter- 
rupted ; for the parts of the arteries which contain no blood must be 
filled by the current of the blood before the impulse could be transmit- 
ted onwards, and the velocity with which the blood itself moves is 
much less than that with which the impulse is propagated. Hence 
Weber explains the fact of the pulse, in an artery affected with aneu- 
rysm, not being synchronous with the heart's action, and with the pulse 
of other arteries ; for the coagulum in the aneurysmal sac, or spaces in 
*t which are not quite filled with blood, may impede the propagation of 
the impulse. 


ial pulse then, we may conclude, is the effect of the oscillations 
ilong the coats of the arteries, and in the blood itself from the 

by the hea/rt.\ 

The elastic coat performs an important 


Motion ofth 


by reacting in the intervals of the heart's action on the blood forced into 

* Wellenlehre. Leipsic, 1825, p. 188. 
•\ Weber, Adnotat. anatom. et physiol. prolus i. 




the arteries at each systole of the ventricles. The blood escapes from a 
divided artery in a continuous stream, although this stream is accele- 
rated at intervals and the periodic acceleration becomes less perceptible 
m proportion as the arteries diminish in size. — 

1 * 1 


.i. , ■ — •-"■ " v,k/wj. i cinai js-s. maim 

this respect the vascular system resembles the fire-engine ; in which the 
water is made to flow in an uninterrupted stream by the elasticity of the 

!!IZ l^ - VeSSe1 ' Wl " Ch continues t0 act u P° n ^ water while the 
™ f *~ ""' " The action of the regulator of the bellows 

piston remits its pressure. 

is the same. By ossification of the arteries this elasticity is Iost,TncTa 

disposition to apoplexy, gangrene, &c. is the consequence. 

Contraction of arteries in proportion to the volume of their contents — 
By virtue of their elasticity, arteries possess the remarkable property of 
diminishing their capacity in proportion to the quantity of blood they 
contain, and in proportion as it escapes from them when divided • for 
this reason, when an artery is divided, the stream of blood which flows 
from it becomes gradually smaller. In a horse, which Hunter let bleed 
to death he found that the aorta had contracted to the extent of more 
than ^th of its diameter ; the iliac artery £th ; the crural artery -ird • 
and that arteries of the thickness of the radial in man were comple'tely' 
closed f The more forcibly the heart acts, the more are the arteries ex 
tended, and the more blood do they contain in proportion to the veins 
On the contrary, when the heart's action is feeble, the coats of the arte' 
nes are more able to resist the impulse of the blood ; they become less 
d 1S tended, and, consequently, contain proportionally less blood than the 
veins. This is what takes place just before death, and it is one cause of 
the absence of blood in the arteries after death ; they are, in fact, for 
the most part, not quite empty, but contain as much blood as they' are 
able to admit in their most contracted state. The gradual diminution in 
diameter which I, as well as Parry and Tiedemann, have observed arte- 
ries which have received no injury. to undergo during the dissection of a 
living animal, must be attributed neither to the stimulus of the air nor 
generally to the vital contractility of the arteries ; it is a necessary 
consequence of the diminished force of the heart's action under such 
circumstances. S,UCX1 

The artenes are not muscular.- The old writers, and many recent 
physiologists, have erroneously regarded the contraction of the arteries 
which follows their dilatation as a muscular act, and have looked upon 
the fibres of the middle arterial coat as muscular fibres. The fibred of 
the elastic coat of arteries are distinguished from muscular fibres by 
chemical characters, as Berzelius has pointed out. The muscular sub- 
stance is soft and lax, and contains more than f tks of its weight of 
water, while the arterial fibre is dry and very elastic : muscular sub- 

* Weber, 1. c. De militate parietis elastici arteriarum. Hildebrandt's Anatomie iii 

p. 69. 

t Abernethy Physiol. Lectures, 224 



stance has the same chemical properties as fibrin of the blood, is soluble 
in acetic acid, with difficulty soluble in mineral acids, with which it 
forms compounds difficult of solution ; while the arterial fibre is insolu- 
ble in acetic acid, but readily soluble in mineral acids, and its solution 
J s precipitated neither by alkali nor by ferrocyanuret of potassium, 
which must happen if it contained fibrin. [Dr. Hodgkin has also ob- 
served that the fibres of the middle coat of arteries, when examined 
by the microscope, do not present the transverse striae which are seen 
on muscular fibres.] Another remarkable difference is, that the pro- 
perty of contracting after extension is preserved by the arteries long 
after death, for several days even ; and fluid impelled by jerks into the 
arteries of a dead animal produces the same phenomena of pulsation 
and of subsequent contraction as are observed in the living body. 

The different arguments for the existence of the pretended muscular 
contractility of arteries, which have been adduced from comparative and 
pathological anatomy, are of no weight. The dorsal vessel of insects, 
and the principal, though not all the vascular trunks of the annelides, 

for instance, the leech, — certainly contract by muscular force. But 
these parts are hearts ; for we have already shown that in the lower 
a nimals, as in the embryo, the heart is nothing more than a dilated part 
°f the vascular system endued with contractility. The acephalous 
monsters, also, in which the heart is almost uniformly absent, have been 
adduced in favour of the muscular contractility of arteries ; for in these 
beings the circulatory system consists of two sets of vessels connected 
at two different points by a capillary system, namely, in the placenta, 
and in the organs of the body ; but here the heart is merely reduced to 
the simple tubular form. In many cases,, also, the vessels of the ace- 
phalous monster are simply branches of the umbilical vessels of a second 
perfect embryo.* The bulbus aortae of fishes and amphibia contracts, it 
is true, quite distinctly. I have even seen the bulbus aortee of the frog, 
when cut away with the aorta, contract as perfectly and distinctly as the 
heart itself. But this part is quite different from the aorta ; it belongs 
to the heart, and is peculiar to those animals which, during their whole 
^fe, or during the first period of it, have a branchial circulation. The 
aorta of frogs beyond the bulbus does not possess a trace of contracti- 
hty ; and Spallanzani,f who otherwise contends against the muscular 
contractility of arteries, is quite wrong when he asserts that the de- 
scending aorta of the salamander continues to pulsate when dissected 
from the body. Dr. 
passing over the great transverse process of the third vertebra in the 
frog and toad, which continued to pulsate after the heart had been re- 
moved. But in this he was mistaken ; there is in this situation in these 

* See page 197 • 

t Be' fenomeni della circolazione. Modena, 1773. 



t I 




animals a peculiar pulsating lymphatic heart,* which is not, however, 
connected with an artery, but with a vein. The oscillating motion of 
the blood after tying the aorta of the frog, when the blood alternately 
advances and retrogrades for a short distance, but without regularity, is 
also no Foof of the muscular contraction of the arteries, although Dr. 
Marshall Hall adduces it as such. It is entirely the result of the elasti- 
city of the arteries, and of the different mechanical impediments to the 
course of the blood. The vena cava of fishes close to the heart possesses 



both m warm and cold-blooded animals. Their observations are perfect- 
ly correct : I have seen the termination of the inferior, and both supe- 
rior cavae of the frog, and of the pulmonary veins and cava of young 
warm-blooded animals, contract regularly ; the venous trunks of the fro- 
continue to contract even after the removal of the heart and auricle" 
But the rest of the venous system exhibits no trace of contractility 
either when under the influence of galvanism or at other times If 
Flourens has seen regular contractions of the large veins in the abdo 
men they evidently must have been produced by the action of the 
lymphatic hearts which I have discovered in the frog, and which pump 
the lymph into the jugular and ischiadic veins. The caudal heart of the 
eel at the extremity of the caudal vein is contractile, but the vein itself 
not at all so. The arteries of the thoracic fins of the chimera, accord- 
ing to Duvernay, and of the electric ray also, according to Dr. T. Davy 
seem likewise to have accessory hearts. 

It has been urged as an argument for the muscularity of arteries, that 
the pulse in corresponding limbs sometimes differs in strength ; for ex- 
ample, in paralysis : but here there are other local causes present to ex- 
plain this anomaly. In paralysed limbs the mutual vital reaction be- 
tween the blood and the solids is diminished ; they are lax and shrivelled 
and often less nourished: while, on the contrary, in active congestion' 
the increase of the vital processes going on between the blood and the* 
texture of the parts,-the increased organic affinity,-i n duces a greater 
flow of blood to the part, and a consequently stronger pulse. In inflamed 
parts, in which there is accumulation of blood and impeded circulation 
through the capillaries, the strength of the pulse is increased IZ 
there is no credible authority for the assertion that the pulse eve/differ 
in frequency in different parts, and it is inconceivable how writers in 
these days can repeat such fables without examining into their accu 
racy. The rapid expulsion of the blood when an artery is punctured 
between two ligatures is also merely the result of the elasticity of the 
coats. Lastly, it has been argued for the muscularity of the arteries 
and their active participation in the motion of the blood, that the ean- 

* See the section on the Lymph and the Lymphatic Vessels, chapter ii 

t Loc. citat. p. 351. 

t Loc. citat. p. 47. 




grena senilis occurs principally where the arteries are ossified. But 
Wedemeyer remarks, that the gangrena senilis sometimes occurs where 


e arteries are not ossified, and such a state of the arteries does not 
always produce gangrene, so that the gangrena senilis requires other 
causes for its production ; and the old error, " cum hoc, ergo propter 
hoc" is of no weight.* 

Not merely, however, are all these arguments for the muscularity of 
arteries without grounds, but there are also counter-arguments to dis- 
prove their muscularity. Berzelius justly remarks, that the strongest 
galvanic and electric stimuli, which produce contractions in all true mus- 
cular structures, excite not the smallest motion in arteries. Nystenf 
repeatedly instituted galvanic experiments on the aorta of criminals just 
beheaded, but did not perceive the slightest contraction ; nor could h 
excite any contractions in the aorta abdominalis of fishes by means of 
galvanism. Bichat had previously performed similar experiments with 
th e same results ; and Wedemeyer also has always failed to produce 
contractions in the carotids and thoracic aorta of many animals with a 
galvanic pile of fifty pairs of plates. I have myself made frequent ex- 
periments, with the aid of galvanism, to determine this question ; and 
^either in frogs, with feeble or powerful degrees of the galvanic influence, 
nor in mammalia, — for instance, rabbits, — with a pile of from sixty to 
eighty pairs of plates, have I been able to produce the slightest trace of 
contraction of the arteries. It has been remarked by Bichat and Trevi- 
r anus, that the heart also is insusceptible of the stimulus of galvanism; 
but Humboldt J observed just the contrary. And PfafF, J. F. Meckel, 
and Wedemeyer, have detected this irritability in the heart in a marked 
degree. I have myself, with a single pair of plates, excited contractions 
not only in a frog's heart which had ceased ^to beat, but have also pro- 
duced immediately most brisk contraction in the heart 6f a dog, which 
had also ceased to pulsate. 

Mechanical irritation has as little effect as galvanism in producing 
contraction of the arteries. The application of chemical irritants, such 
as mineral acids, and muriate of lime, certainly gives rise to constric- 
ts in arteries; but it is by producing a chemical change in their tex- 
Ur e, — in many cases, by extracting a part of the water which they con- 
am ;§ so t h at this contraction by no means tends to prove their muscu- 
arity. The irritability of the muscles in mammalia never endures more 
an three quarters of an hour after death, while the contraction of the 
ar teries on the application of chemical substances can be produced after 
he expiration of several days ; and other non-muscular parts, such as 
" e skin, are also susceptible of it. Zimmerman|| observed contractions 


On all this subject consult Wedemeyer, loc. cit. 
t Recherches de Physiol, et Pathol, chimiques. Paris, 1811. 
X Ueber die gereizte Muskel-und Nervenfaser, 1797. i. 340. 
§ See Hildebrandt's Anat. t. iii. 
|| De irritabilitate. Gbtt. 1751. 





in fat on the application of sulphuric acid. Tiedemann and Gmelin* ob- 
served that sulphuric acid caused arteries to contract which had been 
preserved a year in spirit. Hot and boiling water, also, as Wedemeyert 
remarks, even on the fourth day after death, produces in the human 
skin a contraction and curling very similar to muscular contraction ; and 
we can with acids cause similar contractions in muscular fibres which 
have long lost their irritability, in the peritoneum, and in skin. All this 
proves that most animal tissues, without distinction, whether they pos- 
sess muscular contractility or not, may, both in a living and in the 
dead state, exhibit contractility on the application of chemical irritants, 
from the operation of chemical affinities. These contractions, however, 
are altogether different from muscular contractions, which can no longer 
be induced when the parts have lost their vitality, and are excited not 
merely by chemical, but also distinctly and quickly by mechanical irri- 
tants, and by galvanism. Dr. Hastii 

the contractions produced by chemical agents to be muscular in°their 
nature ; and also when he failed to recognise that the true cause of 
the contraction of the arteries, which follows their dilatation or pulse, is 
the elasticity of the coats,— the same property which produces 
teries injected with fluid by jerks after death, as well as during life, all 
the phenomena which are attempted to be explained by a mere'as- 

g s t 

in ar- 



From all these facts it results 

that the circulation is in no way dependent on periodic muscular con- 
tractions of the arteries ; and that the diminution of diameter of the ar- 
teries after their extension by the impulse of the blood forced into them 
is an effect of their elasticity only. It had hitherto been doubtful 
whether the narrowing of arteries observed in arresting hemorrhage 
from them, in exposing them to the air, and in the operation of torsion, 
is wholly and solely an effect of elasticity, or whether, in addition to 
this, they possess a vital property of gradual, not periodic, contraction 



believes it to exist also in the trunks of the lymphatics. It had not 
however, been actually observed until Schwann made his experiments 
by the application of cold water to the mesentery of the frog and rana 
bombina. After having extended the mesentery under the microscope, 
he placed upon it a few drops of water, the temperature of which was 
some degrees lower than that of the atmosphere. The contraction of 
the vessels soon commenced, and gradually increased, until, at the ex- 
piration of ten or fifteen minutes, the diameter of the canal of an artery 

* Versuche iiber die Wege, &c. 68. 

$ On Inflammation of the Mucous Membranes. London, 1820. Translated into 
the German by Busch. Bremen, 1822. 

§ See also the remarks of Dr. Parry on the arterial pulse. Bath, 1816. Translated 
into the German. Hanover, 1817. 

f Loc. cit. p. 75. 




in the mesentery of a toad, which at first was 0-0724 of an English line, 
was reduced to 0-0276. The diameter, therefore, was reduced to £ or -j ; 
the area, consequently, to \ or ^ of its previous dimensions. The 
arteries then dilated again, and at the expiration of half an hour had 
acquired nearly their original size. By renewing the application of the 
water the contraction was reproduced ; in this way the experiment 
could be performed several times on the same artery. The vital pro- 
perty of tonicity, which gave rise to these phenomena, will very well 
ex plain the partially empty state of the arteries after death ; for the 
arteries, after a certain time, must lose the vital power of gradual con- 
fraction by which they had expelled their blood, and would again dilate, 
staining merely their physical endowment of elasticity, which is not 
°st until decomposition takes place. 

J?orce and rate of the blood's motion in the arteries. — The above enquiry, 
nen, places it beyond a doubt that the only power by which the blood 
ls moved in the arteries is the force of the heart's contraction. We 
ave now to determine the degree of force which is thus exerted by the 
le art, and the force and rapidity of the blood's motion in different parts 
°1 the arterial system. Hales* was the first who made any observations 
°n the height to which the blood rises in glass tubes introduced into 
different vessels : he observed that from the Fig. 15, 

crural artery of the horse it rose 8 or 9 feet 
from the temporal artery of the sheep, 6^ ; 
from the carotid artery of the dog, 4 to 6 
feet ; while from the jugular vein of the horse 
!t rose only from 12 to 21 inches, in the 
sheep b\ inches, in dogs from 4 to 8| inches. 
We shall, however, on this subject have re- 
course chiefly to the accurate researches of 
M. Poiseuille.f M. Poiseuille made use of 
an instrument which he invented for the pur- 
Pose. It was a long glass tube, bent so as 
to have a short horizontal portion, (fig. 15, 
l >) a branch (fig. 15, 2,) descending at right 
an gles from it, and a long ascending branch 
(ng. 15, 3). Mercury poured into the as- 
cending and descending portions will neces- 
sanly have the same level in both branches, 
^nd in a perpendicular position the height of 
lts column must be the same in both. If 
now the blood is made to flow from an artery 
through the horizontal portion of the tube 

* Statical Essays. Translated into the German. Halle, 1748. 
t Magendie's Journal, viii. 272. 


■ v 




into the descending branch, it will exert on the mercury a pressure 
equal to the force with which it is moved in the arteries, and the mer- 
cury will, in consequence, descend in this branch, and ascend in the 
other. The depth to which it sinks in the one branch, added to the 
height to which it rises in the other, will give the whole height of the 
column of mercury which balances the pressure exerted by the blood ; 
the weight of the blood which takes the place of the mercury in the 
descending branch, and which is more than ten times less than the same 
quantity of quicksilver, must, however, be subtracted. M. Poiseuille 
calculated the force with which the blood moves in an artery according to 
the laws of hydrostatics, from the diameter of the artery, and the height 
of the column of quicksilver ; that is to say, from the weight of a column 
of mercury whose base is a circle of the same diameter as the artery, 
and whose height is equal to the difference in the level of the mercury 
in the two branches of the instrument. To prevent the coagulation of 
the blood in the horizontal part of the tube, it was filled with a solution 
of carbonate of potash. According to Poiseuille, the force of the blood's 
motion in the larger arteries, for instance, in the carotid and crural 
arteries, and in the carotid and aorta, is equal; difference in size, and 
distance from the heart, being unattended by any corresponding differ- 
ence of force in the circulation. The height of the column of mercury 
displaced by the blood was the same in all the arteries of the same 
animal. Poiseuille finds that the force of the blood in any large artery 
in a dog will support a column of mercury of 151 millim. or 6 inches, or 
a column of water of 6 feet 10 inches, English; in oxen (mare?)* a 
column of mercury of 161 millim. or 6 inches 4 lines, or a column of 
water of 7 feet 3 inches ; in horses, a column of mercury of 159 millim. 
or 6 inches 3 lines : and, calculating from the former two animals, in 
the mean a column of mercury of 156 millim. or 6 inches lg line, or 
a column of water of 7 feet 1 inch.f 

Poiseuille concluded from his experiments, which seemed to prove that 
the force with which the blood is moved is the same in the most different 
arteries, that to measure the amount of the blood's pressure in any ar- 
tery of which the calibre is known, it is necessary merely to multiply the 
area of the vessel by the height of the column of mercury which is 
already known to be supported by the force of the blood in any part of 
the arterial system. The weight of such a column of mercury will re- 
present the pressure exerted by the column of blood. For example, 

* [M. Poiseuille does not mention the ox in the paper referred to.] 

t [These numbers, if intended as the mean of the results given in M. Poiseuille's 
table, ought to be, 

For the dog 

For the mare . t 

For the horse 

And the mean of the three will be 

a column of mercury of 155-44 millim. 

. 164-36 






Poiseuille estimates the diameter of the aorta at its origin, in a man of 
twenty-nine years, at 34 millimeters. Its area will therefore be 908-2857 
square millimeters. Assuming now that the mean of the greatest and 
least height of the column of mercury found by experiments on different 
animals to be supported by the force of the blood, is equivalent to the 
height of the column which the force of the blood in the human aorta 
would support, we shall have the mean of 180 and 140 millimeters 
consequently 160 millimeters — as the height of this column : 160 milli- 
meters, then, multiplied by 908-2857=145325-71 cubic millimeters, will 
be the amount of mercury in the column, and the weight of this quan- 
tity of mercury, — namely, 1-971779 kilogrammes, or 4 lbs. 3 drs. 43. grs., 
[about 4 lbs. 4 oz. avoirdupois]— will indicate the static force with which 
the blood is impelled into the aorta. By the same calculation, the force 
°f the circulation in the aorta of the ox [mare?] is found to be 10 lbs. 
10 oz. 7 drs. 61 grs. [about 11 lbs. 9 oz. avoirdupois]; in the radial 
artery 4 drs. 

Influence of respiration on the motion of the blood in the arteries. — Poi- 
seuille perceived, by means of his instrument, what Haller and Magendie 
had already observed, namely, that the strength of the blood's impulse is 
increased during expiration ; in which act the chest is contracted, and 
the large vessels in consequence compressed. The column of mercury 
*n his instrument rose somewhat at each expiration, and fell during 
inspiration. M. Poiseuille found that the rise and fall of the mer- 
cury is the same in arteries, the distance of which from the heart 
is different, and that in ordinary tranquil respiration it amounts to 
from four to ten lines. The increase of the blood's impulse by expira- 
tion is in many persons so great, that the pulse at the radial artery 

becomes imperceptible when inspiration is long continued, and the 
breath held. This is the case with myself, and it in some measure 
explains the fable of persons possessing the power of altering the action 
of their hearts at will. 

Effect of anastomoses on the motion of the blood in the arteries. — It was 
formerly believed that the angles at which the branches of vessels are 
given off, according as they are obtuse or acute, influence the rapidity of 
the blood's motion ; the obtuse angle being supposed to retard it. But 
Weber * remarks that this circumstance influences the rapidity of the 
motion of a fluid only when it meets with so little resistance in its pro- 

gress that the sum of the impulses which it receives 

give a deter- 

minate direction to its course ; but that, when the resistance it expe- 
riences is so great that each fresh impulse is lost in overcoming it, the 
an gles at which the branches of the tubes are given off no longer have 
this effect. The fluid in the tubes in this case is everywhere exposed 
to the same pressure, and itself tends with equal force in all directions. 
The reason that the blood flows more slowly in the capillaries than in 

* Hildebrandt's Anat. B. iii. p. 41. 















the larger vessels is, that the aggregate capacity of the small vessels is 
greater than that of the vessels from which they arise. The causes 

tend to diminish the rapidity of the circulation generally are 




increasing friction between the blood and the parietes in the small 
vessels. Anastomoses facilitate the distribution of the blood. Wh 
two arteries anastomose, branches may arise from the anastomosing 
vessels, or from the communicating branch itself. In the first case the 
communicating branch, as far as can be observed with the microscope 
is traversed in the direction which offers the least resistance, and the 
blood is conveyed into that vessel whose capacity is great enough to 
receive the blood of two vessels at the same time. In such cases 
however, the anastomosis is traversed always in one direction. If 
the anastomosis itself gives off a branch, the blood flows either from two 
sides at the same time into this branch, or in one direction only. During 
life, the direction in which the blood flows in anastomoses must vary 
very much, according as accidental pressure affects the part. 

Of the Capillaries. 

lc Structure of the Capillaries. 

Definition of the 


•In all organic textures the trans- 
mission of the blood from the minute branches of the arteries to the mi- 
nute veins is effected by a net-work of microscopic vessels, in the meshes 
of which the proper substance of the tissue lies. This is the appearance 
presented by all parts finely injected ; and it can be seen during life, by 
the aid of the microscope, in any transparent parts, — such as the web of 
the frog's foot, the lungs and urinary bladder of the frog, the tail of the 
tadpole, the incubated egg, young fishes, the gills of the larva of the sa- 
lamander, the wings of the bat, and the mesentery of all vertebrata, and, 
as I have pointed out,* even in some opaque textures of the larva of the 
salamander by means of a simple microscope. The ramifications of the 
minute arteries form repeated anastomoses with each other, and these 
anastomoses terminate at last in a continuous net-work, from which, on 
the other hand, the venous radicles take their rise. The reticulated 
vessels, connecting the arteries and veins, are, on account of their 
nute size, called capillary vessels. The point at which the arteries ter- 
minate and the minute veins commence cannot be exactly defined, for 
the transition is gradual ; but the intermediate net-work has, neverthe- 
less, this peculiarity, that the small vessels which compose it maintain 
the same diameter throughout: they do not continue to diminish in dia- 
meter in one direction and enlarge in the opposite direction, like arteries 
and veins. This, however, does not justify us in admitting with Bichat, 

that the capillaries are a peculiar system of vessels, distinct from arteries 



* Meckel's Archiv. 1829. 



The size of the capillary vessels is proportioned to that of the red pari 
tides of the blood, and can be measured in parts finely injected. Their 
diameter varies from T ^o th to TsW th > even to y ^th of an inch ; but 
*a the mean is most frequently between -y^th and \$g^£kk of an inch. 

Table of the size of the capillaries in different injected parts. 


In the brain 
Human kidney 
Ciliary processes . 

Mucous membrane of 
large intestines 

Lymphatic gland 

Inflamed membrane 


Diameter in fractions 
of an English inch. 

E. H. Weber 
. J\I tiller 



. Do. 4 




2TS4 ™ T§5T 

"2"7 94 

_ l 

8 "§4 6 







The capillaries in their natural state, when filled with blood, and when 
ey are not indeed extended so as when injected, have been seldom 
-measured. In the scrotum of a new-born child, where the cuticle 
could be removed, Weber found their diameter to be ¥ ^L^th of an inch. 
n v ery young animals the capillary vessels are larger than in the adult, 
thus corresponding in size to the red particles of the blood, which are 
also in part larger at the former period. No other elementary tissues 
a re much more minute than the capillaries. The muscular fibres, the 
minuteness of which has hitherto been much overrated, measure, accord- 

ing to Prevost and Dumas, 

74 7 7 

th of an inch in diameter. The primi- 

tive fibrils of the muscles of man are five or six times smaller than the 
red particles of his blood. The primitive nervous fibril in mammalia, 
according to my measurement, is from one-third to one-half the size of 
the red particles of the blood. 

No other tubes in the body are so minute as the capillary vessels. 
The diameter of the biliary ducts of the liver and of the tubuli uriniferi, 

even where they are the finest, is several times greater than that of the 

capillary vessels.* All these different elementary tissues, glandular 
uucts, muscular fibres, and nervous fibrils are surrounded and con- 
nected together by a net-work of capillaries. The primitive fibres of 
Muscles, and those of the nerves, are not themselves traversed by any 
lood-vessels, for they are smaller than the finest capillaries. In exa- 
mining recent and well-injected specimens of these parts, no other ca- 
pillary vessels are seen than those which are distributed in the inter- 
stices of the primitive fibres, and it is the same with regard to the mi- 
nu te ducts of glands. The capillary vessels of the kidneys run every- 
where in the interstices and on the surface of the urinary ducts ; but the 

*or the measurement of different microscopic parts, see the section on Secretion, 

chapter ii. 

P 2 





ducts themselves, according to my observations, contain no blood- 


The form of the capillary net-work is in general very uniform, and 
varies merely in the size of the meshes, or in their being elongated or 
not. In the capillary net-work of muscles and nerves the meshes are 

elongated in the direction of the primitive fibrils on which they are dis- 
tributed. The remarks of Soemmering and Doellinger, and especially 
those of Berres,* with regard to the variety in the distribution of the 
minute vessels in the different tissues, are very correct ; they do not, 
however, refer to the capillary vessels themselves, but to the minute 
arteries and veins which ramify and divide still farther, before forming 
the capillary net-work. Soemmering observes, that the mode of ramifi- 
cation in the small intestines resembles a tree which is not in leaf, in the 
placenta a tuft, in the spleen an asperge or sprinkling-brush, in the 
muscles a branch of twigs, in the tongue a hair-pencil, in the liver a 
star, in the testicle and in the choroid plexus of the brain a lock of hair, 
in the Schneiderian membrane a trellis-work. In the branchiae the ar- 
teries and veins take the direction of the branchial lamella, the arterial 
current ascending on one side, the venous descending on the other. 
The form of ramification of the vessels of tendons, which are not imme- 
diately connected with the long twig-like vessels of the muscles, is, ac- 
cording to E. H. Weber, dendritic. In the cortical portion of the kid- 
neys there are peculiar glomeruli of blood-vessels in the midst of the 
capillary net-work.f Huschke has very recently proved that the minute 

rtery which enters one of these vascular ganglia, after making several 
convolutions, again issues from it, and then becomes continuous with the 
capillary net-work.J At the extremity of each of the villi which form 
the tufts of the human placenta, a minute artery becomes directly conti- 
nuous with the minute returning vein. This can be seen distinctly in 
the water-salamander. Thus the mode of division of the minute arteries 
presents many varieties, while the capillary net-work itself differs merely 
in the size of the meshes, and in their more oblong or equal-sided figure. 
Of this I have been convinced in the course of my researches on the 
glands ; for in these organs, however various the distribution of the mi- 
nute ducts may be, the capillary vessels have always the simple reticu- 
lated form, and do not follow in their arrangement the distribution of the 
ducts. In the medullary portion of the kidneys, where the urinary 
tubuli are collected into pyramidal bundles, the small arteries, and, as 
I have recently more than once satisfied myself by injection, the veins 
also, run in the form of long straight vessels between the urinary ducts, 

* Med. Jahrb. d. Osterr. Staates.Bd. 14. 

f See the section Secretion, chapter ii. and my work De Gland, struct, penit p. 

5 Tiedemannund Treviranus, Zeitschrift fur Physiol. 4 Bd. 1 H. p. 116, tab. vi. fig. 8. 




and have commonly been mistaken for ducts injected from the blood- 
vessels ; but even these straight blood-vessels give off capillaries which 
form elongated meshes, and, diminishing in size as they run from the 
cortical portion towards the mammella, terminate at last on the mam- 
m ella itself, in a fine net-work surrounding the openings of the urinarv 

1 •* 

ducts. In the same way the smaller branches of the blood-vessels run 
along between the muscular and nervous fibrils ; but the capillary vessels 
themselves form here a net-work around the parallel fibres of the 
Muscles and nerves, just as they do in the testicle around the convoluted 
tubuli seminiferi, and in the cortical portion of the kidney around the 
convoluted tubuli uriniferi. The small arteries in the branchiae of the 
salamander also follow the mode of division of the branchial lamella?, and 
terminate at the extremity of each lamella in descending branchial veins ; 
but between the two vessels there is also a net-work in the smallest la- 
mella, which Rusconi and others have overlooked, but in which I have 
actually seen the red particles of the blood circulating. 

Number of the capillaries and size of the meshes in different parts 
The parts in which the net-work of capillaries is the closest, that is, iri 
which the meshes are the smallest, are the lungs and the choroid mem- 
brane of the eye. In the iris and ciliary body, even, the interspaces 
are somewhat wider. The vascular net-work is also very close in the 
Mucous membranes of the lungs, liver, and kidneys, and in the cutis 
vera. In the choroid of the turkey the interspaces are of the same size, 
or even smaller than the capillary vessels themselves. In the human 
lung the interspaces are, if anything, smaller than the tubes which form 
the net-work. In the human kidney, and in the kidney of the dog, the 
diameter of the injected capillaries, compared with that of the inter- 
spaces, is in the proportion of one to four, or one to three. The brain 
receives a very large quantity of blood, but the capillaries in which it is 
distributed through its substance are very minute, and less numerous 
than in some other parts, so that the blood must pass through it into 
the veins more quickly than in other organs. E. H. Weber found the 
diameter of the capillaries in the brain, compared with the long diameter 
°f the meshes, in the proportion of one to eight or ten ; compared with 
the transverse diameter, in the proportion of one to four or six. Tn the 
Mucous membrane — for example, in the conjunctiva, — and in the cutis 
vera, the same observer found the capillary vessels themselves much 
larger than in the brain, and the interspaces narrower, — not more than 
three or four times wider than the vessels. In the periosteum the meshes 
Wore much larger.* The bones, cartilages, ligaments, and tendons are 
the parts which have the smallest number of blood-vessels and capil- 
laries. At the line limiting muscle and tendon, the great difference in the 
vascularity of the two parts is very observable ; the greater number of 

* Weber in Hildebrandt's Anat. 3 Bd. p. 45. 





the blood-vessels of the muscles are, according to Doellinger, reflected 
back again, and have no immediate connection with the scanty vessels 
of the tendons. Prochaska* observed the same relation between the 
free portion of the synovial membrane and that which covers the arti- 
cular cartilages. I saw a very beautiful injected preparation of the car- 
tilages of the trachea, larynx, and costal cartilages made by Fuchse in 
the museum of Fremery at Utrecht. The existence of vessels in the 
internal shining layer of the serous membranes has hitherto been doubt- 
ful ; but some injections of the peritoneum by Bleuland, which I saw at 
Utrecht, make me hesitate to adopt Rudolphi's opinion, namely, that the 
vessels of serous membranes are situated in the subserous cellular tissue; 
and Schroeder Van der Kolkf has injections of the peritoneum, which 
prove indubitably that this membrane contains vessels. 



It is still doubtful whether 
the vitreous humour and the substance of the cornea are supplied with 
capillaries. Microscopic observations and minute injections have shown 
that the capillary vessels are merely the fine tubes which form the 
medium of transition from arteries to veins, and that no other kind of 
vessel arises from them ; that the minute arteries have no other mode of 
termination than the communication with the veins by means of the 
capillaries ; in a word, that there are no vessels terminating by open ex- 
It is the more necessary to demonstrate this fact, which 
minute anatomy has clearly shown, since Haller unfortunately adopt- 
ed, and thus contributed to confirm, the crude notions of his predeces- 
sors regarding the open terminations of arteries. He admitted that 
arteries terminate in five ways: 1st, by openings on the surface of 
membranes; 2nd, in lymphatics; 3rd, in secreting canals; 4th, in fat; 
and, lastly, in veins. But in those times the secretion of mucus and fat 
could not be understood without presupposing the existence of open ex- 
tremities of the blood-vessels. After Mascagni, Hunter, Prochaska, and 
Soemmering had contended with success against this hypothesis of the 
open termination of arteries, it still remained a matter of doubt whether 
there was not a communication between the blood-vessels and the se- 
creting canals of the glands. My researches, however, on the structure 
of all glands, in which better auxiliary means have been had recourse 
to, such as the injection of the secreting canals themselves, the use of 
the microscope, and the history of the development of the embryo, to- 
gether with similar observations by Huschke and Weber, have proved 
that no such communications exist in any secreting glands, and that the 
radicles of the secreting canals, however various their form in the dif- 
ferent glands, are always closed at their radicle extremity. The exist- 
ence of exhalent vessels also, which even Bichat admitted* and supposed 

Disquisitio Anatoraico physiologica organismi humani ; Vieunae, 1812 • p. 06. 
t Observ. Anat. path. 27. 



to be open side-branches of the capillary vessels, is purely hypothetical. 
An exhaling membrane, such as the peritoneum, has merely reticulated 
capillary vessels spread out over a great superficies, and the fluids are 
exhaled into the cavities by permeating the substance of the organ it- 
self; all animal textures being permeable to fluids by virtue of the pores 
which, though not visible, must necessarily exist even in the smallest 
molecules of the animal substance which are capable of being softened 
by fluids. It is owing to this porosity that when arteries are injected 
w ith a solution of size coloured with cinnabar, a colourless fluid exudes 
°n the surface of the membranes, as was pointed out by Mascagni, the 
colouring particles not being able to pass through the pores. 

Serous vessels, that is, branches of the blood-vessels which are too 
minute to allow the passage of the red particles, and which are traversed 
therefore merely by the lymph of the blood, may possibly exist, but they 
have not been demonstrated. In favour of this hypothesis those parts 
are adduced in which no vessels carrying red blood have hitherto been 
discovered, namely, the cornea, the capsule of the crystalline lens, and 

the vitreous body. 

Parts in which existence of blood-vessels is doubtful. — The existence of 
vessels in the substance of the cornea is doubtful ; they have never been 
injected. Nevertheless, penetrating ulcers and granulations are formed 
in the cornea, which can scarcely be conceived to occur without the 
agency of vessels. I have repeatedly seen, in calves of nearly the full 
time, vessels in the conjunctiva of the cornea, which contained red blood, 
and which could with a lens be traced more than a line over the margin 
of the cornea. Henle has injected and made drawings of these vessels : 
they measured from -j -g^th to -^ th of an inch, and the finest twigs were 
not then injected ; their trunks, which arose from a circular vessel that 
ran around the cornea, were even somewhat larger than this. The pre- 
parations of these parts I have in my possession. Professor Retzius has 
by means of injection been able to see the same thing in the adult ani- 
mals. These vessels, belonging merely to the very surface of the cornea, 
prove at the same time that the conjunctiva is really continued over the 
cornea, which Eble denies.* It is well known that in inflammation the 
cornea contains vessels carrying red blood. I saw at Utrecht, in the 
possession of Schroeder Van der Kolk, a most beautiful injected prepa- 
ration of a slightly inflamed eye, in which the conjunctiva as well as the 
aqueous membrane were injected. The posterior capsule of the lens 
even in full-grown animals contains vessels carrying red blood, derived 
from the branch of the arteria centralis, which traverses the vitreous 

humour to reach the posterior capsule. I have seen these vessels some- 
time^ filled with blood in the fresh eyes of the calf and ox ; Zinn saw 

* See Henle De membrana pupillari aliisque membranis oeuli pellucentibus. Bonnae, 






the membrana 


inner border of the 

• • 


the same thing. Henle has shown that the vessels of the posterior cap- 
sule in the foetus communicate with vessels of the zonula Zinni or corona 
cihans, and of the ciliary processes ; and he has injected and given a 
representation of the communicating branches. In the embryo of 
mammal* the vessels of the posterior capsule are connected by a 
very vascular membrane, which I have discovered,— 
capsulopupillaris— with the vessels of the pupillary' membrane.' 
new membrane is stretched between the 

and the inner border of the corona ciliaris, or the borde7of the 'capsule 
ot the lens, and contains numerous parallel longitudinal vessels, which 
pass from the iris and pupillary membrane to the corona ciliaris and 
posterior capsule of the lens. In the anterior capsule the vessels are 
extremely difficult to demonstrate. In inflamed eyes they are distinct 
both on the anterior and posterior wall of the capsule, as I saw in an 
excellent injected preparation of a cataractous eye in Schroeder Van 
der Kolk s collection at Utrecht. The zonula Zinni, or corona ciliaris 
appears fr om Henle's and Schroeder's injections, to be a vascular tgan' 

humours! "v" "^^ *" ** »™ hh ™<* * the transpaL; 

I have not seen any injected vessels in the vitreous body. Schroeder 
had a preparation m which something like vessels were apparent ; bu 
they might be merely adherent colouring matter. Henle has also 
shown me a preparation of the vitreous humour, in which there was 
something resembling injected vessels; but it was not convincing. 
However, I do not despair of seeing this part also injected. 

All these facts however, render it very probable that even the cornea 

and capsule of the lens, to which vasa serosa have been hitherto as- 

cnbed, are really provided with vessels carrying red blood; and it is 

certain that the capsule of the lens of the eye of the ox, as well as 

„LrT ' 0nj " nCtiva in the fu % developed foetus of the sheep, are 

Zint IZ: f 1 l0 ° d - The V6SSe,S ° f the C ° raeal **™^ - 
TaZett" 7r° US than th ° Se ° f thG Sder0tic C0 "J— 

that'pa r rof the , """I "r 6 ^^^ th ° Se tW ° P arts as between 
that part of the membrane which is free, and that which covers 

the articular cartilages. E. H. Weber remarks, very correctly that a 
single stratum of capillary vessels is not at all recognisable by Ihe Y e 
alone; the colourless appearance of the parts of which we have been 

Thete'errTr ^ "" "? ** ** -* "° ^^ 

K„ ^ a /*u • equa "y free from vessels, and transparent ; but - 

by the aid of the microscope capillaries become evident in it. 

. . . jr — . — The question whether the 

mnute capillaries have membranous parietes is important. It has been 
the universal testimony of observers, from Malpighi to Doellin^er that 





in living animals no membranous walls are discoverable by the aid of 
the microscope. Doellinger* regards the blood as fluid animal sub- 
stance, the substance of the organs as solid blood. Gruithuisen saw the 
blood flowing in the free spaces between the acini of the liver in the 
r og: this is seen, according to my experience, much more distinctly in 
the liver of the larva of the triton, which alone I found adapted for 
the observation^ Wedemeyer doubted the existence of membranous 
Panetes, when he observed the broad currents of blood and the small 
ls lets of solid tissue in the lungs of the salamander. 
Hunter, Doellinger, 


Wedemeyer, Meye 

ar *d Oesterreicher, also deny the existence of membranous parietes to 
the capillary vessels; while Leeuwenhoeck, Haller, Spallanzani, Pro- 
chaska, Bichat, Berres, and Rudolphi are of the contrary opinion. 

The argument for the non-existence of membranous tubes, which Doel- 
hnger and Oesterreicher deduce from the development of new vessels, 
cannot be applied to vessels already formed; and more accurate researches 
a Ppear, indeed, to refute altogether the hypothesis of the circulation of 
the blood in canals without membranous tubes. The facts that fluids 
ejected into the arteries pass into the veins without extravasation, and 
that currents cross above and below each other without uniting, have 
already been adduced. The number of the currents, and indeed the 
smallness of the islets of solid matter between them in the pulmonary 
membrane of the frog and salamander also tend to prove that membra- 
nous tubes must exist ; for these small islets would otherwise be them- 
selves sometimes involved in the currents. But there are also direct 
means of proving the existence of the membranous tubes around the 
capillary streams. For this purpose we must select a very delicate 
parenchyma, which easily softens and dissolves in water, so as to leave 
behind the net-work of capillaries. In a piece of the cortical substance 
of the kidney of a squirrel which had been laid in water for a short time 
only, but long enough to have become softened, the capillary vessels 
which are interlaced around the tubuli uriniferi appeared to me, when I ex- 
amined them by the microscope, to be independent parts. In the choroid, 
J ns, and ciliary processes, the capillaries are still more evidently substan- 
tial independent parts. They can, however, be demonstrated most dis- 
tinctly in an organ which Treviranus has discovered, — I mean the leaf- 
like organ in the cochlea of the internal ear in birds. C. Windischmann + 
concludes, from his dissections, that these lamina? are merely folds and 
Wrinkles of a membrane which arches over the spiral plates of the 
cochlea. The membrane is extremely delicate and pulpy; its soft sub- 
stance is however traversed by an extremely beautiful net-work of vessels 
which Windischmann has injected from the carotid ; it dissolves easily in 

* Denkschriften der Akad. zu Miinchen, 7. 

t De penitiori auris structura in amphibiis, cum tab. iii. Bonnae, 1831. Lips, apud Voss 

f See Meckel's Archiv. 1829. 





water, leaving the beautiful vascular net-work with the meshes empty.* 
In the uninjected state, also, the vascular net-work remains after the 
pulpy substance has been dissolved. In other parts, the parietes of the 
capillaries must be regarded merely as surfaces formed of the substance 
of the organs in a more condensed state, not as very substantial distinct 


2. Circulation in the Capillaries. 

As viewed by the microscope.— \i the circulation in any transparent 
part of a living adult animal is examined by means of the microscope, 
the blood is seen to flow through the minute arteries and capillaries with 
a constant equable motion. In very young animals its motion, though 
continuous, is accelerated at intervals corresponding to the pulse in the 
larger arteries, and a similar motion of the blood is also seen in the capil- 
laries of adult animals when they are feeble : if their exhaustion is so 
great that the power of the heart is still more diminished, the red parti- 
cles are observed to have merely the periodic motion, and to remain 
stationary in the intervals ; while, if the debility of the animal is extreme, 
they even recede somewhat after each impulse. These observations of 
Wedemeyer, which I must confirm as the result of all my experiments, 
are of great importance ; for they prove that, even in the state of the 
greatest debility, the action of the heart is sufficient to impel the blood 
through the capillary vessels. The pulsatory motion of the blood in the 
capillaries cannot be attributed to an action in these vessels themselves, 
for when the animal is tranquil they present not the slightest change in 
their diameter. 

It might be supposed that, even in the natural state, the blood flows in 
this pulsatory manner through the capillaries, and that the apparent re- 
gularity of its motion is attributable to the rapidity of the circulation, 
which, when viewed by the microscope, appears even greater than it 
really is ; but the fact that the blood flows in an equable stream from 
the veins, proves that the effect of the impulses communicated to the 
blood is, in the natural condition, really lost in the capillary system. 

The cause of the equable motion of the blood in the capillaries must be 

sought in the elasticity of the arteries. The elastic coat of the artery 
acts like the compressed air in the air-vessel of the fire-engine. Doing 
each pulsation it is distended by the blood forced into it, but during the 
intervals of the heart's action it contracts again so as to force on the 
blood, and convert its merely periodic motion into a continuous although 
periodically accelerated one ; by the time that the blood reaches the 
minute arteries, the impulse given to the blood by each contraction of 
the ventricle is lost in thus dilating the arteries, while the continuous 
motion— the result of their elasticity— remains. During its course through 

* See Winciischmanii, Ioc. cit. tab. ii. 



the vessels, the circulation of the blood will necessarily be modified by 
the unequal obstructions that it meets with in the smaller vessels, causing 
!t to be checked for a time in one vessel while it circulates more quickly 
through others ; but in the capillaries themselves the pulsatory motion 
will no longer be perceptible. When an animal,, however, is much 
weakened, and the propulsive power of the heart consequently dimi- 
nished, the arteries become distended by less blood at each pulsation, and 
*n their turn react with less force upon the blood. The cause, therefore, 
which in the natural state renders continuous the periodic motion of the 
blood, is not under these circumstances brought into action, and the blood 
nioves forward only at the time of each beat of the heart, the effect of 
which is then perceptible in the capillaries. The oscillating motion of 
the blood in debilitated animals is said by Koch* to be independent of 
the heart's action. To both Wedemeyer and myself, however, it ap- 
peared to be wholly dependent on the contraction of the heart being too 
feeble to overcome the resistance offered by the capillaries ; so that some 
part of the blood, in the intervals of the contractions, receded again, not- 
withstanding the presence of the valves. 


of resistance which the capillaries offt 

from the results of the experiments instituted with that view by Hales 
and Keill. The mode which Keill adopted was to compare the quan- 
tities of blood which flowed in a given time from the divided crural 
artery and from the crural vein of a living dog. The quantity derived 
from the crural artery compared with that from the vein was in the 
proportion of 1\ to 3, so that from these data the resistance to be over- 
come in the capillaries would seem to neutralise T % ths of the force with 
which the arterial blood moves. 

Hales f injected the mesenteric artery of a dead animal with water by 
allowing a column of that fluid 4^ feet high to press into the artery, 
having previously divided the intestines along the line opposite to the 
insertion of the mesentery. The quantity of water which flowed from 
the divided capillaries amounted to one-third only of the quantity which 
escaped in the same time when the larger branches of the artery were 
divided ; so that the resistance offered by the capillaries equalled two- 
thirds of the force with which the water was forced into them. 

of the capillary 

To make a comparison of the rate of 

the circulation in the capillaries and arteries, we must take the mean 
r apidity of the blood's motion in these vessels at different times and in 
different situations; for in the arteries the velocity of the circulation is 
greater at the moment of the pulse than in the intervals of this act, and 
,n the capillary system it is seen by the microscope to vary very much 
m different capillary vessels. 

* Meckel's Archiv. fur Anat. m Physiol. 6 Bd. p. 216. 
-j- Statical Essays. 




If the area of all the branches of a vessel united was always the same 
as that of the vessel from which they arise, and if the aggregate area of 
the capillary system was equal to that of the aorta, or, in other words, if 
the aggregate capacity of the tubes through which the blood passes was 
the same in all the degrees of their ramification,— the mean rapidity of 
the blood's motion in the capillaries would be the same as in the largest 
arteries; and, supposing a similar correspondence of capacity to exist in 
the veins and arteries, there would be an equal correspondence in the 
rapidity of the circulation in them. It is quite true that the force with 
which the blood is propelled in the arteries, as shown by the quantity of 
blood which escapes from them in a certain space of time, is much 
greater than that with which it moves in the veins, but this force has to 
overcome all the resistance offered in the arterial and capillary system, 

this resistance must indeed be overcome by the heart itself; so that the 
excess of the force of the blood's motion in the arteries is expended in 
overcoming this resistance, and the rapidity of the circulation in the ar- 
teries, even from the commencement of the aorta, would be the same as 
in the veins and capillaries, if the aggregate capacity of the three sys- 
tems of vessels were the same. 

But since the aggregate area of the branches is always greater than 
the area of the trunk from which they arise, the rapidity of the blood's 
motion will necessarily be greatest in the latter, and will diminish in 
proportion as the aggregate area of the vessels increases. 

The motion of the blood in the capillaries is wholly dependent on the 
hearts action. — Many physiologists, believing that the power of the heart 
is not sufficient to propel the blood through the capillary system, have 
imagined the existence of other auxiliary forces, such as contractions of 
the capillaries themselves, or a spontaneous motion of the blood, — neither 
of which, however, has been demonstrated by direct observation. On 
the contrary, it is irrefragably proved, that the motion of the blood 
through the capillaries is effected solely by the action of the heart ; 
for in animals, of which the strength is much exhausted, the impulse 
communicated to the blood by the ventricles is visible in the capillaries ; 
and the flow of blood from a divided vein is accelerated during ex- 
piration, proving that the increased impulse given to the current of 
blood by the compression of the great vessels in the chest is also 
transmitted through the capillaries to the veins. The dependence of 
the circulation of the blood in the veins on the action of the heart 
is also proved by the following experiment of Magendie. He applied 
a ligature to the leg of a dog, the crural artery and vein not beino* 
included. The vein was then tied separately, when it was seen to 
become turgid below the ligature, with the blood returning from the 
limb ; and, if it was punctured at that part, the blood spirted out in 
a full stream. When the crural arterv was comnressecL fhp flrmr A ? +i* A 



blood from the vein gradually ceased, but recommenced when the 
pressure on the artery was remitted, Poiseuille, by means of the 
instrument already described, measured the pressure of the blood in 
the portion of a vein most distant from the heart, and found it to 
be exactly proportioned to that of the blood in the arteries, increasing 
and diminishing according as the force of the blood in the latter 
vessels was greater or less.* 

The differences of the bloods motion in different capillaries arise from 
Mechanical causes. — Wedemeyer's description of the course of the blood 
lr * the anastomosing capillaries agrees perfectly with what I have ob- 
served. Sometimes, he says, the red particles flow rapidly from one 
current into a second, as if by attraction. In other cases the current 
which they join is very rapid ; but they are arrested, as it were, in 
the collateral current, and only from time to time find means of 
entering. Sometimes a red particle is even thrown back out of the 
r apid current into the weaker stream, and is then again repelled. I 
have also remarked that the same anastomosing branch between two 
currents sometimes receives the blood in one direction, and some- 
times in the other, and that variations of pressure, and position, and 
motions of the animal, are always the causes of these changes. AH 
these variations in the capillary currents are then, just as in currents 
of water on irrigated land, merely the results of mechanical causes. 
In the most minute capillaries, which are not red, nor even yellow, but 
quite transparent, there is merely a single line of red particles separated 
by unequal intervals, and from time to time no red particles are seen 
in these colourless vessels ; but I have observed no canals through 
which red particles did not occasionally pass, and which, therefore, 

deserved the name ofvasa serosa; and Wedemeyer, who says he has 
seen such vasa serosa, himself confesses that some of the red bodies 
traversed them from time to time. The red particles do not rotate 
on their own axis while passing through the capillaries; in the frog 
they appear, for the most part, to move with the long diameter in 
the axis of the vessel, but frequently they are placed obliquely, and 
their position suffers many changes from the mechanical influence of 
the coats of the vessels; the red particles themselves are quite passive, 
and never present the slightest sign of spontaneous motion. Several 
observers have asserted, that, in passing through a narrow portion of 
the vessel, the red particles are sometimes compressed and thus 

I have never seen this occur; the observation may have 
been erroneous, and have arisen from the elliptic particle having been 
presented to the eye in different positions at different times. 

All the red particles which are carried into the capillary system by the 
arteries are returned from it by the small veins ; none are apparently 

* Miiller's Archiv, 1834, p. 365. 






retained in the capillaries, at least in an animal which is not enfeebled 

Doelhnger and Dutrochet maintain that they have seen the red par" 

tides arrested in their course in the vascular canals, and become united 

with the tissue. I have 

arrest of the red particles, particularly 

myself, it is true, frequently observed this 

in enfeebled animals, and, 



formerly, thought it possible that the red particles of the blood might 
m this manner lose their mobility ; but more accurate observations have 
convinced me that these stagnant globules are soon again set free 
and that it is only in a state of extreme debility that a complete' 
stagnation— or rather coagulation -of the blood occurs in the minute 
vessels : the occurrence of coagulation under such circumstances can- 
not however, be supposed to explain the process of nutrition, being; 
rather the very opposite of it. Not a single observer has confirmed 
the assertion of Doellinger relative to the nutrition which he supposed 
to take place by union of the globules with the tissue, and the observa- 
tions which I shall adduce in another place render it very probable 
that n«tntion is effected by a totally different process. 

, r, t . , - - blood.— Treviranus, Carus, Doellinger, 

and Oesterreicher have adopted the opinion of Kielmeyer, that the 
blood is endued with a power of self-propulsion, which they suppose 
to be exerted in the capillaries during life independent of the heart's 
action, and to continue after the latter has ceased. This opinion seem- 
ed to be confirmed by the observations of Wolff 
asserted that, in the chick, blood is formed in the areaTasculosa,' 
~ from the periphery of the area vasculosa towards the 

heart, before the latter has pulsated. The latter part of this state- 
ment is not confirmed. Baer doubts its accuracv: it appeared ro 
him that the pulsation of the heart is first seen, and soon afterwards 
the motion of the blood, in the space of the transparent area, and 
that the influx of the blood from the area vasculosa to the heart 
took place last of all.* Wedemeyer also has not been able to convince 
himself that the motion of the blood in the area vasculosa commences 
before the pulsation of the heart. The other arguments for the inde- 
pendent motion of the blood in the capillaries are derived from the 
continuance of the blood's motion in parts removed from the bod y 
The idea of spontaneous motion in a fluid independent of attraction or 
repulsion from the sides of another object is itself inconceivable • but 
even omitting that from consideration, the facts brought forward in 
favour of the hypothesis, although in part correct, do not appear to me 
to justify the conclusions deduced from them. There are two con- 
ditions under which the blood in the capillaries of a transparent part 
separated from the body may still be seen in motion by means of 




the microscope:—!. As long as the blood continues to flow from the 

* Burdaoh's Physiol, ii. 2G1. 





divided vessels. Thus, for ten minutes after separating the foot of a 
frog from the body, I could still perceive motion of the blood from the 
minute vessels towards the larger ; that is to say, towards the openings 
°f the divided stems. These movements, in my opinion, depend simply 
°n the escape of the blood from the divided vessels, which by their 
elasticity contract to a less diameter than they had before while in the 
statd of forcible extension. The narrowing of the vessels can, in fact, 
be perceived by the aid of the microscope. If the divided surface 

with the leg of 
blood ceases sooner, and after five or 

from which the blood flows 
the frog, the escape of the 

is elevated, together 

S1 x minutes not the slightest motion is perceptible in the capillary 
vessels. Wedemeyer's* observations agree in most particulars with 
m ine, only that he does not mention the space of time that the 
motions continue. 2. The second condition under which the motions 
ar e perceptible is, when the direct rays of the sun are allowed to 
fall on a moist part separated from the body. The surface of the part 
then becomes dry and wrinkled so quickly, that the change is percep- 
tible to the eye, This causes a more rapid emptying of the capillary 
vessels, which, when the direct rays of the sun are transmitted through 
the part, is attended by a flickering appearance. Thus, in the wing 
°f a bat removed from the body, a trace of this flickering motion of 
the blood will be perceived in spots even for many hours, but only 
at that part where the most intense rays of the sun are at the time 
shining through. The extraordinarily rapid shrivelling of the surface 
may be seen with the naked eye. If the part which is becoming 
dry is moistened again, the shrivelling, and with it also the flickering 
motion in the interior of the vessels, ceases for some moments, but 
is renewed as soon as the evaporation and drying recommences. Even 
after a day and a half had elapsed I could still see a flickering in the 
interior of the moistened wing when it was illumined by the direct 
light of the sun. Baumgaertnerf observed the blood in the frogs foot 
continue in motion from three to five minutes after ligature of the 
artery, and attributed the motion to a reciprocal action exerted 
between the nerves and blood ; it most probably arose from the con- 
traction of vessels which had previously been distended ; anastomoses 
also might give rise to such appearances. The ingenious experiments 
of Baumgaertner unfortunately do not clearly prove what they are 
intended to do. Moreover, according to my observation, the circula- 
tion in the capillaries generally ceases very quickly on the compression 
of the artery of the limb, when the spontaneous motion of the red 
particles ought certainly to be seen if it exists at all. Having de- 
stroyed the vitality of the heart of a frog by the application of liquor 

* Ueber den Kreislauf des Blutes ; Hannover, 1828 ; p. 233. 
t Beobachtungen uber die Nerven u, d. Bint. Freiburg, 1830. 




some time per- 
it depended 


kali caustici, I could, by means of the microscope for ^ 

nrl V b e abr 0ti ° n / ^ ^ " ** ^"^ ~* but - «*-"-« 

probably on the compression of the blood by the elastic coat of the 

In c Zcl th t T-° U ? y beCn " a State 0f f0 -ble distension. 
In one case the blood in the capillaries remained fluid above an hour, 
and from time t t adyanced a litt]e> then recede ^ and 

then again moved. These motions were probably produced by the 
compression of the vessels by slight motions of the frog, or of a single 
set of muscles of the leg. I deny, therefore, the existence of a self- 
propelling power in the blood. 

If the blood moves independent of the heart's action, it must be by 
virtue of an attraction exerted on it by the solid walls of the capillary 
vessels, which seems to be what Baumgaertner and Koch suppose. If 
this attraction of the blood by the capillaries and the organised tissue 
really took place, it might produce an accumulation of blood in a part, 
such as is seen in the phenomenon of tumescence ; but we cannot con- 
ceive how such attraction could aid the circulation of the blood, for it 
would cause the blood to become stationary in the capillaries, unless it 

exelTont 1 ?- 1 T kT f raCti ° n ° f the Ca P iUarieS for *» blood is 
exerted only while the blood retains its arterial character, and ceases 

when it has become venous. It is only by such an affinity that the capilla- 
ries could the circulation. The congestion of certain parts at 
particular times is, however, no argument for the existence of this auxil- 
iary force, for in this congestion there is accumulation as well as attrac- 
tion of the blood. Although the circulation of the sap in plants, effected 

by means of attraction only, shows us the possibility of the occurrence 
of a similar phenomenon in animals, still there are at present no direct 
observations which prove it in a conclusive manner.* 


, . . . Although it be denied that the 

circulation is in any way aided by an attraction between the blood and 
the capillaries, the existence of such an attraction or affinity may, never- 

theless, be admitted in the 

instance of the « tumescence, turgor 

f This condition of 

tumescence m annnals ,s analogous to phenomena which are so evident 
to plants, such as the afflux of sap to the fruit-bud, which contains the 

impregnated ovum. 

The mutual vital action 

or affinity between the blood and the 

tissues of the body, which is an essential part of the process of nu- 
trition, is, under many circumstances, greatly increased ; and an accu- 
mulation of blood in the dilated vessels of the organ is the result. It 

* See the account of the circulation in the lower animals, pp. 1 55, 156 

of thfslh eb ! nSbl * eit ' ^ tm ' g0re VUali - LipS ' i795 - ThC " eW Which this ™thor takes 
oi tne subject is very erroneous. 

. t -- 




th S6en ' f ° r 6Xample ' in the g enita]s during the state of sexual desire, in 

e uterus during pregnancy, in the stomach during digestion, and in 

*e processes of the cranial bones, on which the stag's antlers afterwards 

rest, during the reproduction of these parts. The local accumulation 

° blood, with the dilatation of old and the formation of new vessels, is, 
owever, seen most frequently in the embryo, in which new organs are 
eveloped in succession by a process of this kind ; while, on the other 
and, other organs, such as the branchiae of the salamander and frog, and 
!e tad of the latter animal, become atrophied and perish as soon as the 

^tal affinity which existed between the blood and their tissues ceases to 

De exerted. 

A he phenomena of turgescence have been supposed to be dependent 
on an increased action or contraction in the arteries. But arteries pre- 
sent no periodic contractions of muscular nature; and a persistent con- 
ation of the arteries, unless it were progressive,— vermicular, as it 
were,-— or aided by valves arranged in a determinate direction, would be 
quite inadequate to produce a state of turgescence in any part. 

the b 


ony processes which bear the antlers of the stag, we must pre- 
suppose the existence of an increased affinity between the blood and 
e tissue of the organ. This condition may be excited very suddenly, 
as is seen in the instantaneous injection of the cheeks with blood in the 
act of blushing, and of the whole head under the influence of violent 
Passions ; in both of which instances the local phenomena are evidently 
induced by nervous influence. The active congestion of certain organs, 
of the brain, for example, while they are in a state of excitement, is a 
similar phenomenon.* 

If the organ which is susceptible of the increased affinity between the 
blood and the tissue, is, at the same time, capable of considerable dis- 
tension, tumefaction and erection take placet 

oee tne remarks at Uonorden, in Meckel's Archiv. 1827, 537 ; and of Wedemeye 

*• c. 412. 

t The principal erectile parts are the penis, which presents the phenomenon in the 
JS est degree, the clitoris and the nipples in females, and the appendages on the head 
ome birds,— such as the turkey, meleagris gallopavo. In the erectile structures the 
/« sels are susceptible of great dilatation, and the veins very sinuous, forming very 
dil^T US anaStomoses and P lexuse s 5 so that the capacity of all the plexuses, when 
bio a eXCeeds be y° nd comparison that of the arteries and veins which convey the 
oo to and from them. In the undistended state, the same quantity of blood is sent 
bio , eeXtensile vesse,s as returns fr om them ; but, during the state of erection, the 
^ood is probably retained in them, in consequence of the affinity between it and the pa- 
rtes of the vessels being increased. 

When the part is supported by a strong fibrous tissue, lying in the intervals of the 
enous Pauses and connected with an external fibrous tunic, as is the case in the cor- 

oi a cavernosa penis, it acquires, during the state of erection, great tension and firm- 





1 1 n 


• --' 




Contractility of the capillaries. — Many substances, such as those called 
astringents, — for example, alum, — seem to have the property of producin 

an approximation of the molecules of living animal matter — a conden- 


Injected matters pass pretty freely from the arteries of. the penis into the veins, par- 
ticularly in the corpus spongiosum urethra, and glans. Professor M. J. Weber has 
shown to me a series of beautiful preparations of the penis injected from the arteries. 
(Cuvier, Anat. Compare, t. iv. ; Moreschi, Meckel's Archiv. v. 403 ; Ribes, ibid. 447 ; 
Tiedemann, Meckel's Archiv. ii. 95 ; Panizza, Osservazioni Antropo-zootomico-fisio- 
logiche. Pavia, 1830.) In the corpus cavernosurn of the penis of the horse there are 
a number of pale red bundles of fibres lying among the anastomosing veins. These 
fibres, for the most part, run longitudinally, but they are connected by transverse 
bands. Viewed by the microscope, they do not present any resemblance to muscular 
fibres. By boiling in water for seven hours they yield no gelatine. Their solution in 
acetic acid is precipitated by ferrocyanuret of potassium. All we can conclude from 
this analysis is, that they do not belong to the cellular, tendinous, or elastic tissues. 

I could excite no contraction in the fibres of the corpus cavernosurn, by means of gal- 
vanism, in a living horse. Hence they would seem not to be muscular. (Mulleins 
Archiv. 1834, p. 50 ; 1835, p. 26.) 

The principal exciting cause of the erection of the penis is, as is well known, nervous 
irritation, originating in the part itself or derived from the brain and spinal marrow. 
When the spinal marrow of an animal is irritated, or destroyed with a hot wire, erec- 
tion and emission of semen are produced. Congestion of the brain and spinal cord has 
the same effect, and it is from this cause that the above-mentioned phenomena are 
sometimes produced in persons hanged. The nervous influence is communicated to the 
penis by the pudic nerves which ramify in its vascular tissue. Guenther has observed 
that, after division of these nerves in the horse, the penis is no longer capable of erec- 
tion. (Meckel's Archiv. 1828, p. 364.) The stallion on which the experiment was 
performed was led to a mare ; he showed desire to cover, but no erection of the penis 
took place. On the following day the penis was swollen, but not in a state of erection. 

It has been supposed by some French writers, Chaussier and Adelon, and, in Ger- 
many, by Stieglitz, (Pathologische Untersuch. i. 175,) that the afflux of blood is not the 
first step in the process of erection ; that it is, in fact, the consequence of a spontaneous 
dilatation of the tissue. But to this it may be objected, that there is no known instance 
of active dilatation, and that artificial injection of the penis produces a state exactly 
similar to that of erection. Stieglitz, at the same time, supposes that the trunks 
of the veins may probably have the power of contracting so as to close their canal; 
but some experiments which I made on the vena dorsalis, in the dog and the ram, 
are directly opposed to this hypothesis. Krause (in Stieglitz's work, p. 186, and 
in Mueller's Archiv. 1837) attributes to the erectores penis the power of compressing 
the veins of the penis, and of thus producing erection. Houston, again, (Dublin Hos- 
pital Reports, 1830,) has described, in different animals, certain muscles situated be- 
tween the penis and the arch of the pubes, arising from the descending branches of the 
pubes, and uniting with each other in the middle line over the vena dorsalis. I have 
never been able to find them. The erection may be strengthened, at its commence- 
ment, by a voluntary contraction of the muscles of the perinaeum ; but if the essential 
cause of erection is not in action, this effect is only momentary. The erectores penis 
can be contracted at will, but this action will not produce erection if the penis is pre- 
viously lax. 

My discovery of the remarkable structure of the arteries of the corpora cavernosa 
penis throws new light on the phenomena of erection. The arteries of the corpora 
cavernosa have two sets of branches. The one set are the ultimate ramuscules, which 




Fig. 1 6. 

sation of the matter,— and thus a contraction of the tissues which it forms, 
t is to this effect on the capillaries and small arteries that we must at- 
tribute the action of such astringents, and of cold, in arresting hemorrhage 
from wounds. 

There can be little doubt but that the effect of cold and astringents 
°n the animal textures is much greater during life, for it is only during 
lf e that the peculiar state of the skin, called « cutis anserina/* can be pro- 
uced. If the " cutis anserina" arose simply from the blood being repelled 
rom the ^rface, so as to leave the capillaries less turgid, the skin collapsed, 
a ^d the follicles consequently more prominent, it would be produced by 
th e same cause after death. It must, therefore, be dependent on a vital 
contractility of the skin; the follicles becoming more evident in conse- 
quence of the contraction of the surrounding skin. A similar contraction 
* s produced in the prepuce by the action of cold, and in a still greater 
b e gree in the dartos. The vital insensible contractility here referred to 
ls distinguishable from muscular contractility by the contraction of the 
Part in which it is excited being gradual and feeble ; moreover, muscular 
contractions are excited by the nervous stimulus under all circumstances, 

^ermmate in the minute radicles of the veins, and are destined for the nutrition of the 

The other set come off from the side of the arteries, and consist of short, slightly 

curled branches, terminating abruptly by a rounded, apparent- 

y closed, extremity, turned back somewhat on itself; these are 

sometimes single ; sometimes several arise by one stem, form- 
ln g a tuft. (See fig. 16.) I have named them arteries helicince. 

I hey project into the venous cells, and are found principally 
ni the posterior part of the corpora cavernosa, and of the 
corpus spongiosum urethra. They are most distinct in 
man. Although no openings can be discovered in the coats 
of these free arterial excrescences, yet there is no doubt but 
that it is through them that the blood, which is ordinarily carried into the texture 
of the corpora cavernosa by the minute nutrient branches of the arteries, is in the 
act of erection poured directly into the venous cells and sinuses. When the arteria 
corporis cavernosi is injected with size and vermilion, the injected matter always fills 
1 e venous cells ; and if it is afterwards washed from them, the arteriae helicinae will 
% e seen injected. The means by which during life they are enabled to force blood 
jnto the cells, must be the increased attraction exerted between their coats and the 
ood by the nervous influence transmitted to them by the spinal cord, in consequence 
o which attraction an increased quantity of blood goes to them. This throws new 

^t, at the same time, upon the mutual action of the blood and smaller vessels in 
cr parts, and upon the phenomenon of active turgescence, or turgor vitalis. (Muel- 

er s Archiv. 1834, p. 202, tab. xiii.) The blood is returned from the corpora cavernosa 
Partly by small veins, running at the sides and on the surface of these bodies into the 

ei *a dorsalis, partly by deeper veins which issue from the corpora cavernosa at their 

oot, and enter immediately the venous plexus, situated behind the symphysis pubis. 

he fact, then, that the vena dorsalis does not return the blood from the deep veins, 

°Ws that no pressure on the former vein alone can cause accumulation of blood in the 

Penis. (See the article "Erection," by Mueller, in the Encyclop. Worterbuch d. me- 

dicin. Wissensch.) 


Q 2 






while this i 

ible contraction of the skin is not excited by its specific 
causes, such as cold and nervous affections, unless under such circum- 
stances as at the same time determine a diminished flow of blood to the 
skin, which is probably dependent on some sympathetic influence on the 
heart's action ; while all stimulants which induce a greater afflux of 
blood to the surface produce vascular turgescence, but not the pheno- 
menon of cutis anserina. The insensible contractility displayed by the 
skin is probably possessed, in a greater or less degree, by all the soft 
parts which are organised ; and there is no reason to suppose that the 
minute arteries and capillaries are not endued with it. Every stimulant, 
however, does not excite it. Thus the contraction of the small arteries 
and capillaries, which causes the arrest of hemorrhage in operations, is 
produced by the sudden action of specific influences^ — such as cold ; 
while other stimuli, — heat, for example, — might, by increasing the tur- 
gescence of the part, have quite the contrary effect. Wedemeyer states 
that no contraction is produced in the capillaries by the agency of gal- 
vanism, but that the blood becomes stagnated in them from coagulation 
taking place. In the small arteries, however, he perceived a distinct 
permanent contraction, which did not arise, he says, from the action of 
the acid developed at the positive pole, for it took place even when he 


applied the negative pole to the vessel. It might, however, in this 
case, be dependent on the action of the alkali developed at the negative 


Action of different substances on the capillaries. — Direct experiments to 
determine the action of different substances on the capillary vessels, by 
watching the changes produced by the application of these substances to 
the vessels of transparent parts, promised at first to increase consider- 
ably our knowledge of the action of the capillaries. But these experi- 
ments have left our knowledge of the subject in the greatest confusion. 

The most interesting observations are those of Thomson, Wilson, Has- 
tings, Kaltenbrunner, Wedemeyer, and Koch. Two orders of changes 
are observed on the application of chemical agents to the small arteries, 
capillaries, and veins. In many instances,, — for example, whenever com- 
mon salt was applied, — dilatation of the capillaries ensued after a few 
minutes. In Wedemeyer's experiments, however, on the application of 
salt to the small arteries of the mesentery of the frog, contraction to the 
extent of ^th of their diameter was the first effect, and this was fol- 
lowed by great dilatation. The application of ammonia was observed 
by Thomson to be followed by contraction of the vessels., with dimi- 
nished rapidity of the circulation ; while Wedemeyer and Hastings 
found it produce dilatation of the vessels with stagnation of the blood. 
Oesterreicher also observed dilatation follow the application of a weak 
solution of ammonia, while he found that concentrated matters produce 





contraction of the vessels, and at last stagnation of the blood. Alcohol, 
according to Hastings, produced contraction of the capillaries : hot water 
had the same effect in frogs ; the application of ice was also followed by 
contraction. Hastings remarked that these substances frequently caused 
contraction first, and afterwards dilatation. From the application of 
tincture of opium, tartaric acid, very dilute muriatic acid and alcohol, 

lined no constant result. In two instances only did 
alcohol cause retardation of the circulation, without, however, having 
excited distinct contraction in the small arteries. When dilatation of 
the vessels is produced, the circulation is generally at the same time 
retarded. Thomson is the only physiologist who has observed accele- 
ration as well as retardation of the circulation accompanying dilatation 
°i the vessels; and this was after the application of common salt. In 
vessels in which the substance applied has produced contractions, the 
rate of the circulation also varies, being sometimes retarded, sometimes 

I he blood must, cceteris paribus, flow more rapidly in a contracted 
vessel ; but if its fluidity had been diminished, or coagulation induced, 
b y the substance applied, its motion will be retarded. In a dilated ves- 
sel, the circulation must, cceteris paribus, be slower: increased rapidity 
°r the circulation in such a state of the vessels can be accounted for 
°nly on the supposition that dilatation from an external cause may dimi- 
nish the friction in the vessel. 

The explanation of the phenomena detailed above is at present quite 
impossible. The contraction in all these cases may be a vital action of 
the animal tissue, or it may be merely a chemical effect, which would 
be produced equally well on dead matter,— -the substance applied may 

be supposed, for example, to extract from the tissue a part of its water. 
The dilatation of the vessels produced by certain substances may be a 
state of turgescence arising from an increased organic affinity excited 
between the blood and the tissue : it is, however, just as possible that 
!t is merely the result of endosmosis. A salt when applied to a part 
permeates the tissue till it reaches the capillary vessels ; an attraction 
*s then exerted between the salt and the blood, which has a tendency 
to dissolve the salt, as the salt has a tendency to dissolve itself in the 
bl ood ; the blood will in consequence of this affinity be arrested and 
accumulated in the capillaries ; the capillaries will be dilated, and the 
circulation in them retarded. It is very probable that dilatation of the 
capillaries, when produced by the application of a salt, is dependent on 

endosmosis alone. 

of the capillaries in infU 

The results of the experi- 

ments detailed above appear, then, to admit of such different expla- 
nations, that they can be of scarcely any assistance in determining the 
state of the capillaries in inflammation. I shall therefore simply detail 







the phenomena of this morbid process as they have been observed and 
described by Thomson,* Kaltenbrunner,f and K'och.J 

The minute vessels of an inflamed organ contain at every stage of 
the process an increased quantity of blood : at the commencement of 
the inflammation the blood flows into the capillaries in larger quantity 
than natural, circulates through them rapidly, and escapes from them into 
the veins without great difficulty ; but in a more advanced stage of the 
disease the circulation becomes impeded, and stagnates in the distended 
capillaries ; at first single vessels only, but at last all the capillaries of 
the part, are filled with blood, which is motionless, and very probably 
coagulated ; at any rate it has undergone some change. Koch says that 
the colouring matter of the globules is dissolved by the serum in the 
inflamed part : this, however, is not probable, for in that case the fibrin- 
ous exudation would be coloured red. According to Koch, no new 
vessels are formed in inflamed parts ; it must, however, be remembered 
that they are certainly developed in the fibrin effused during the in- 
flammatory process. When the inflammatory congestion has attained 
its highest degree, in membranes which have a free surface, they pour 
out the dissolved fibrin of the blood. The fibrinous fluid or lymph coa- 
gulates on the surface of the membrane, forming pseudo-membranes. If 
the inflammation is situated in a part where there is no free surface on 
which this exudation can take place, the coagulable matter accumulates 
in the capillary vessels themselves. When the consequent arrest of the 
circulation takes place only in isolated tracts of the capillary system, 
while the circulation of the organ is carried on, though incompletely, by 
the other capillaries, the part is merely rendered denser in texture, — a 
state which is called hepatisation, when it occurs in the lungs ; in other 
organs, induration. If the violence of the inflammation is so great that 
the circulation in the organ is completely arrested, and the blood in all 
the capillaries is not merely coagulated, but decomposed, while the tissue 
itself undergoes decomposition, such a part is said to be gangrenous, or 
mortified, — its vitality is lost. Thomson has observed, that the vessels 
in gangrenous parts are sometimes filled with coagulated fibrin, some- 
times obliterated by the inflammatory process. Mortification ensues 
more readily when the nervous energy is diminished, and in paralysed 

If, after the congestion and effusion of lymph have taken place, the 
inflammation is still kept up, either by the persistence of the same 
causes, or by the accession of new, the tissue of the organ undergoes a 
peculiar change. The decomposed molecules of the tissue are separated 

* Lectures on Inflammation, translated into German by Krukenberg. Halle, 1820. 


Monach. 1826. 

t Koch has given a review of the subject, with original experiments, in Meckel's 

Archiv. Bd. vi. 


m the form of pus,— a matter consisting of globules larger than those of 
the blood. No one, not even Kaltenbrunner, has observed satisfactorily 
by the aid of the microscope the formation of pus. Cold-blooded animals 
ar e not adapted for this experiment ; it ought to be instituted on mam- 
malia, — on the wings of the bat, for example. 

Nature of the inflammatory process. — In inflammation the phenomena 
ar e so far similar to those of vital turgescence, or orgasm, that the blood 
ls attracted in increased quantity to the part, and escapes from it with 
uiniculty. But the effects of inflammation show that it would be a great 
error to regard it as identical with increased vital action. In inflam- 
mation the function of the part is, in the first place, disturbed by the 
Material change produced in it by the exciting cause of the inflammation ; 
subsequently, nature makes an effort to repair this material change. In 
the reproduction of the antlers of the stag, in the phenomenon of erec- 
t*on, and in the turgid state of the uterus after conception, the turges- 
cence is really combined with increased vital power, and the excitement 
and the vital energy in these cases advance to a certain extent pari 
passu, but in inflammation the material change is the only part of the 
process which goes on increasing. The appearance of turgescence 
which arises from the blood being attracted and retained by the in- 
flamed tissue, — perhaps for the purpose of restoring them to their natural 
condition, — is gradually exchanged for that of gangrene. The latter 
state ensues as soon as the material change is so great that the tissues 
lose the power, which in the healthy state they possess, of preserving 
the vital properties of the blood, which then itself becomes decomposed 
in the vessels. Inflammation is produced by irritation of the capillaries, 
but itself consists neither in an increased nor in a diminished vitality. 

It is a peculiar state which may occur with the general vital powers in 
their normal state, or with these powers depressed ; and which, in pro- 
portion to the degree of its developement, if in an important organ, 
always exhausts the vital powers, even if they were not previously 
enfeebled. It is in fact a mutual action, morbid in its nature, which is 
set up between the tissues and the blood, in consequence of the ma- 
terial changes produced in the part, and which is compounded of the 
original lesion of the part, of a local tendency to decomposition, and of 
a vital action striving to counterbalance the tendency to decomposition, 
-the vital action of the part sometimes overcomes the morbid tendency, 
as is exemplified by a healing wound ; sometimes it does not. 

Influence of the nerves on the circulation in the capillaries 
physiologists have recently sought to prove that the nerves have a great 
share in keeping up the circulation in the capillary vessels. Treviranus 
and Baumgaertner have done most to support this theory. But al- 
though it is certain that turgescence of the tissues — their attraction of 
the nutritive fluid — is dependent on the influence of the nerves, it does 







not necessarily follow that this influence should at all aid the circulation . 
The numerous experiments of Baumgaertner are far from being con- 
vincing. He himself confesses that many of them are not strictly con- 
clusive ; and, unless proofs are free from doubt, their number does not 
better establish the fact. Baumgaertner directed a strong galvanic 
current through the ischiadic nerve to the foot of a frog ; the irritability 
of the nerve was destroyed, and in most cases the circulation in the 
limb was arrested. But here, by destroying the nervous energy of the 
part, the influence by which the coagulation of the fibrin is prevented 
was abolished ; and, besides this, it must be remembered that galvanism 
itself will produce coagulation of the albumen in the blood. After de- 
struction of the spinal cord and brain, Baumgaertner saw the motion of 
the blood in the capillaries become slower, although the heart continued 
to beat. But here, again, the motion of the heart itself was weakened ; 
and experiments which rest upon an indefinite Ci more" or " less/' are not 

Treviranus asserted that division of the ischiadic nerve in the fro°- 
caused the circulation in the web of the foot to cease. But even Baum- 
gaertner denies that this is the case if the web is kept properly moist. 

The numerous experiments of Dr. Wilson Philip* also fail completely 
to establish the influence of the nerves on the circulation in the capilla- 
ries. The retardation or cessation of the circulation in the capillaries 
which he observed when opium or infusion of tobacco were applied to 
the brain and spinal cord, or when these parts were suddenly destroyed, 
was dependent on the effect which was produced simultaneously on the 
heart. Kochf also made an ingenious and simple experiment with a 
view to determine the same point. He amputated the leg of a small 
frog, and found that the motion of the blood in the capillaries of the 
web of the foot continued for three minutes only. He then, in another 
frog, divided all the parts of the thigh but the ischiadic nerve, by which 
he left the limb attached to the body ; and he now perceived motions in 
the capillaries for the space of a quarter or half an hour. I have repeated 
this experiment, but not with the same result. The motion of the 
blood in the capillaries continued about ten minutes when the limb 
completely separated from the body in strong frogs ; and there was no 
difference in respect to time when it was left attached by the ischiadi 


nerve. In this experiment an error may be induced by the frog retaining 
the power of producing voluntary contractions of the muscles of the limb 
as long as the ischiadic nerve maintains its connection with the nervous 
centres. After each contraction of the limb, a slight motion of th 
blood in the capillaries is perceived ; but the cause of this is evidently 

* Experimental Inquiry into the Laws of the Vital Functions. 
t Meckel's Archiv. 1827, p. 443. 


< ' 



In the following experiment I avoided this cause of error. I laid 
open the spinal canal in a frog, and while my assistant, M. Hoevel, ap- 
plied the wires of a simple galvanic circle to the posterior roots of the 
spinal nerves,— the irritation of which excites no contractions of the 
muscles,— I watched the circulation in the foot of the frog. At the mo- 
ment when the galvanic stimulus was applied, no change was produced 
!n the motion of the blood. This experiment, however, is not conclu- 
sive, for it may be the anterior roots of the nerves from which an influ- 
ence on the circulation is derived. 

From the facts which we have detailed, it appears most probable that 
the nerves do not really assist in carrying on the circulation in the capil- 
laries, although it is certain that nervous influence is the principal cause 
0r " the accumulation of the blood in the capillaries of certain parts durino- 
the state of vital turgescence. The observation that in a frog much 
exhausted the impulses communicated to the blood by the feeble con- 
tractions of the heart are perceptible in the capillaries, proves that no 
other force than that of the heart is required to support the circulation. 



The action of the heart is aided 

m accomplishing the circulation through the veins by the action of the 
valves with which the veins are provided, and which are so arranged 
that any intermitting pressure on the veins favours the motion of the 
blood towards the heart. Hence the want of proper bodily exercise 
must have an injurious effect on the circulation, if it were merely from 
the loss of the aid which the action of the muscles affords to the motion of 
the blood in the veins. The veins themselves, with the exception of the 
root of the vena cava and pulmonary veins, have no contractile power.* 

of the 


contractile power of the heart is insufficient for the completion of the 
circulation of the blood, ascribe some share in the blood's motion to a 
power of suction which they suppose to be possessed by the heart 
They imagine that, after the heart has contracted, its cavities return to 
a state intermediate between dilatation and contraction, so as to give rise 
to a relative vacuum. The degree to which the heart dilates after its con- 
traction, independent of being dilated by a fluid, can be but slight. But 
let us inquire how much effect is to be attributed to such a dilatation of 
the heart. During the contraction of the auricle, the great veins be- 
come more distended with blood, either on account of the reflux of 
part of the blood of the auricle into them, or from that which they were 
pouring into the auricle being arrested in its progress. During the 
dilatation of the auricles the distension of the veins diminishes. This 
was observed by Magendie and Wedemeyer, and it is exactly what I 

* See pages 170 and 204. 










again each time to its former level. 

have myself witnessed in the dog. It is necessary to know this fact 
before forming an opinion on the following experiments. Wedemeyer 
and Guenther, having tied the jugular vein in a horse, made an opening 
into it between the ligature and the heart, and introduced a catheter, 
to which a bent tube had been cemented. The longer descending 
branch of the glass tube (two feet in length) was placed in a glass filled 
with water. At first the inspirations and the contractions of the heart 
were nearly simultaneous and of the same frequency, — namely, thirty in 
a minute, — and the coloured water rose suddenly two or more inches in 
the glass tube at the moment of each inspiration and pulsation, and sank 

The inspirations gradually became 
twice as frequent as the pulsations of the heart ; and Wedemeyer and 
Guenther now observed for a long period, that the rise of the fluid did 
not take place at each inspiration, but at every beat of the heart, and 
consequently simultaneously with each dilatation of the auricle. This 
experiment seems to prove beyond doubt the sorbent power of the 
heart. This power is not, however, the principal cause of the blood's 
motion in the veins ; for the fact, that large veins when divided continue 
to pour out blood from that portion of the vein which is distant from the 
heart, and connected with capillaries and arteries, proves that the pro- 
pelling power of the heart's contraction extends to the veins; and Ma- 
gendie has shown that the stream of venous blood from the lower end 
of a divided vein becomes stronger during each expiration; which 
proves that the effect of the compression of the arterial trunks which 
takes place during expiration extends to the veins ; and it is evident 
that the force thus exerted is far inferior to that of the heart's con- 

The circulation in fishes also shows that the passage of the blood 
through a system of capillaries does not destroy the vis a tergo with 
which it is propelled; for in these animals the heart sends the blood 
through two systems of capillaries ; first through that of the branchiae, 
from which it passes into the systemic arteries, which, as Nysten has 
shown, have themselves no contractile power; and afterwards through 
the general capillary system of the body. In all vertebrate animals, in- 
deed, the vis a tergo derived from the heart is sufficient to propel the 
blood through the capillaries of the liver, after it has already circulated 
through the capillaries of the other abdominal viscera. 

Influence of 

Sir David Barry has recently given a new 

turn to these inquiries respecting the circulation in the veins. The 
heart, he says, when distended with blood, completely fills the pericar- 
dium ; but, when it contracts, it no longer occupies the same space, and 
a partial vacuum ensues. To enable the auricles to fill this vacuum, the 
blood rushes into them from the great venous trunks. But Sir D. 
Barry attributes more importance to the effect of inspiration. During 





spiration, he says, a partial vacuum is formed in the thoracic cavity, 
and all surrounding fluid must strive to enter it to fill the vacuum ; the 
atmospheric air rushes in through the trachea, distending the lungs in 
proportion to the dilatation of the thorax, and in the same way the 
fl uids in the vessels of the body being subject to the pressure of the at- 
mospheric air, will be forced into the cavity of the thorax and distend 
"e trunks of the great vessels contained in it. But in consequence of 
a vacuum being formed in the pericardium at each contraction of the 
eart, the blood of the great venous trunks is drawn into the auricles to 
fal1 this vacuum; so that the afflux of blood to the cavity of the thorax 
during inspiration takes place principally towards the auricles. To 
P r ove the correctness of his theory, he performed the following experi- 
ment: he introduced one end of a bent tube into the jugular vein of an 
a nimal, the vein being tied above the point where the tube was inserted; 
fre inferior end of the tube was immersed in some coloured fluid. He 
now observed that at the time of each inspiration the fluid ascended in 
" e tube, while during expiration it either remained stationary, or even 
sank. When the tube was introduced into the pericardium itself, he 
observed the same ascent of the fluid. 

a oiseuille has instituted some experiments to determine the 
question, but in a more accurate manner. He employed the instrument 
described at page 207 (fig. 15). A solution of carbonate of soda was 
poured into the tube, filling both the perpendicular branches till it rose 
to a level with the horizontal portion ; this point was the of the scale. 
When the horizontal portion of the instrument thus prepared,, is connected 
with the cavity of a vein, if any suction is exerted in the vein, a part of 
the fluid will be drawn out of the instrument, and its level in the great 
perpendicular branch ( 3 > fig. 15) will fall ; if, on the other hand, any 
pressure is exerted by the blood in the vein on the fluid in the horizon- 
tal portion, the level of the fluid in the branch ( 3 ) will rise. The in- 
strument was connected with the jugular vein of a dog ; and it was 
observed that during expiration the fluid rose in the branch ( 3 ), and 
fell during inspiration ; the rise at first equalled 3 inches 4 lines, the fall 
^as 3 inches 6 lines below the previous level ; afterwards the fluid as- 
cended only 2 inches 4 lines, and fell 2 inches 9 lines below the level. 
During great muscular efforts, the ascent of the fluid at the time of ex- 
piration was as much as 5 inches 6 lines, or 6 inches 1 line above the level ; 
a nd the descent during inspiration 9 inches 5 lines, or 9 inches 11 lines 
below it. These experiments, which on repetition afforded the same 
results,, confirmed Barry's opinion that during inspiration the venous blood 
°f the body is drawn into the venous trunks in the thorax. The effect 
of expiration, on the other hand, in repelling the blood, is prevented by 
the action of the valves, and by the pressure exerted on the blood in the 
veins by the muscles. 








Barry, however, has estimated too highly the influence of inspiration 
on the motion of the blood. It is observable only in the large veins 
near the thorax. Poiseuille could not detect it by means of his instrument 
in veins more distant from the heart, — for example, in the veins of the 
extremities. The act of inspiration empties the large veins in the 
thorax, and less resistance is in consequence offered to the entrance of 
the blood from the other veins ; but it cannot be the principal cause of 
the motion of the blood in the veins ; and in the reptiles, which breathe 
by the movements of deglutition, in fishes, and in the foetus, no move- 
ment of inspiration is performed. There can be no doubt, therefore, that 
the same power that moves the blood in the arteries, also effects its motion 
in the capillaries and its return to the heart through the veins ; and that 
by the effect of inspiration on the great venous trunks, by the sucking 
action of the heart, and by the action of the valves, a part only of the 
resistance which opposes the course of the venous blood is overcome. 

The changes produced in the motion of the blood by the contraction 
of the thorax during expiration, give rise to the tumefaction of certain 
parts. The vascular trunks are in expiration so compressed, that the 
blood is sent with increased force into the arteries, while the influx of 
blood into the right auricle is arrested. The consequence of this is not 
merely that the jugular veins become distended, but that even the brain 
is more fully injected with blood. In cases where a portion of the skull 
has been removed by the trephine, the brain is consequently in most 
cases seen to be elevated somewhat during expiration, and to collapse 
again during inspiration. Magendie declares that he has also observed 
this to take place in the spinal cord. In the natural state, the cranial 
cavity being inclosed by solid walls, no such movements of the brain can 
be caused by respiration, the brain cannot then alter its volume. All 
that has been advanced in favour of such a change of volume taking 
place in the natural state, is refuted by the physical impossibility of its 


The effects of impediment to the circulation in the larger veins are 
effusion of the watery and albuminous parts of the blood into the serous 
cavities and the cellular tissue. The fibrin is not effused. This 
may be explained perhaps by the circumstance that the fibrin is being 
constantly removed by the lymphatic vessels. 

State of the vessels after death. — It is not rare to find blood in the 
arteries after death ; for instance, such is the case in persons hanged, 
in those drowned, or suffocated by vapour of charcoal, also after inflamma- 
tion, and in ossified arteries.* But commonly the arteries are found to 
contain proportionally less blood than the veins. It is the property of 
arteries, as is well known, to contract both in diameter and length, so as 
to adapt themselves, to a certain extent, to a diminished quantity of blood. 

* Otto Path. Anatomie, i. . 343. 






By virtue of this property of elasticity, the arteries at the moment of 
death force onwards the blood contained in them, while they assume 
the narrowed state in which they are afterwards found.* At a later 
period the quantity of the fluid in the vessels must be greatly diminish- 
e d by the fluid part of the blood escaping through their porous coats, 
which like all animal tissues are susceptible of imbibition. Dr. Carzonf 


ascribed the absence of blood in the arteries after death chiefly to 
the action of the lungs. He supposed these organs to contract after 
the last expiration by virtue of their elasticity still further, so as to produce 
*n the chest a vacuum, to fill which blood is drawn from the body into the 
large venous trunks. When he had opened the thorax of the animals while 
dying, he found that the arteries afterwards contained a larger quantity 
°f blood than under other circumstances. But he has certainly over- 


rated the elastic power of the lungs. Dr. Parry believed the empty 
state of the arteries to be the result of their tonic contraction, J which 
he supposed to take place immediately after death, so as to force their 
contents onwards into the veins, but to cease after a time, when the 
arteries again become dilated. Dr. Parry states that he has observed 
ese changes in the diameter of the arteries after death. This expla- 
nation is more probable than that afforded by the unconfirmed hypothesis 
°f an attraction which the capillaries are supposed to exert on the red 

particles of the blood in the arterial state, but not on those of venous 






a. Of Absorption. 

Before the discovery of the lacteals by Asellius in 1622, the office 
of absorption was ascribed to the veins ; but after the discovery of 
Asellius,, and when it was known that similar vessels existed in most 
parts of the body, they were supposed to be the sole organs of absorp- 
tion. The fact of the lacteals becoming turgid with chyle soon after 
taking food, and the arrangement of their valves, which is such as to fa- 
vour the course of the chyle and lymph towards the thoracic duct, and 
to prevent its motion in the opposite direction, are corroborative of the 
opinion that they perform the function of absorption. It has, however, 
at different times been remarked that the lymphatics cannot be the sole 
organs of absorption. The absorption of the osseous matter in the in- 
terior of bones in the formation of their cells, and the absorption of the 

* See page 193. 

f Inquiry into the causes of the motion of the Blood, pp. 97. 108. 117. 

See page 206. 

§ See page 224, 




alveoli of the teeth in old persons, are facts well known, and yet there are 
no lymphatics in bones. It is certain also that pus, portions of the lens, 
and of blood in the interior of the eye, become absorbed, and neverthe- 
less no lymphatics have been discovered in the interior of that organ. 
Lastly, we need only instance the absorption of the yolk of the egg by 
the germinal membrane, in which no one will assert that there are lym- 
phatics during the first days of incubation ; if the invertebrate animals, 
which possess no lymphatics, did not sufficiently prove the possibility of 
absorption being performed without the agency of these vessels. 

But it required a long course of experi- 
ments to establish the fact of the immediate absorption of matters 
into the blood without the aid of lymphatics. Magendie, Emmert, 



Lawrence, Coates, Tiedemann, Gmelin, and Westrumb, have 

particularly distinguished themselves in this inquiry- 


cept the crural artery and vein, leaving merely these vessels, which were 
dissected quite clean, and freed from their cellular coat, to maintain the 
connection of the limb with the trunk ; two grains of a strong poison 
(the upas ticuti) were then inserted into a wound in the foot. The 
action of the poison was as rapid as if the limb had been previously 
uninjured. The symptoms began to show themselves in four minutes, 
and in ten minutes the animal was dead. 

The same physiologists made a similar experiment on a convolution of 
intestine in a dog, in which the lacteals had been previously made visi- 
ble by giving the animal a good meal. The intestine was tied at two 
points, with an interval of fifteen or sixteen inches ; the lacteals of this 
portion of intestine were then tied each with two ligatures and divided. 
They satisfied themselves that no other lacteals ran from this part of the 
intestine, so that its only means of communication with the circulation 
were the arteries and veins. They now injected into the intestine two 
ounces of decoction of nux vomica, and retained it there by a ligature. 
Symptoms of poisoning ensued in six minutes/ 

Magendie laid bare one of the jugular veins in a young dog of six 
weeks old, and isolated it from surrounding parts in its whole length, so 
that he could pass a card beneath it. He then applied freely to the 

The sym- 


vein a watery solution of spirituous extract of nux vomica. 

ptoms of poisoning appeared before the fourth minute; when a similar 

experiment was made on an adult dog, the symptoms came on in ten 


Segalas % has repeated these experiments in a different manner. He 
tied the blood-vessels, or merely the veins of a portion of intestine, the 

* Elements of Physiol, translated by Milligan, 4th ed. p. 314. 

t Magendie, 1. c. p. 358. 

% Magendie's Journal de Physiol, ii. p, 117, 




lymphatics being uninjured, and was then unable to kill a dog, even in 
an hour, by means of poison introduced into the intestine. 

The results of Mayer's* experiments, in which he injected a solution 
prussiate of potash into the lungs, must be more accurately detailed. 
As early as from two to five minutes after its injection into the lungs, 
the salt could be detected in the blood by the green or blue precipitate 
Produced in the serum by the addition of muriate or sulphate of iron. 
-I he rapidity with which the prussiate of potash enters the blood is too 
great for it to be explained by means of the slow circulation of the 
ymph. The salt was detected in the blood long before it was perceptible 
lr Uhe chyle, and in the left side of the heart before a trace of it could be 
detected in the right cavities ; while, if the absorption had been effected 
by the lymphatics, the course of the lymph being first into the venous 
blood of the body, the salt absorbed ought to be first detectible in the 
J^ght cavities of the heart. Eight minutes after its injection into the 
Un gs> prussiate of potash shows itself in the urine. It is found also in 
the skin, in the fluid of the articular cavities, in the abdominal cavity, 
m the pleura, in the pericardium, in the fat, in the fibrous mem- 


branes, — for instance, the dura mater, — in the aponeuroses, in the arach- 
noid, in the capsular and lateral ligaments, in the internal ligaments of 
joints, — for example, the cruciate ligaments of the knee-joints and the 
hgamentum teres of the acetabulum, — in the perichondrium, and in the 
valves of the heart. 

The kidneys were the only glands in which it was detectible ; 
prussiate of potash, like most salts, being excreted from the blood bv 
the kidneys. The liver did not become stained on its external surface 
when the salt of iron was applied, but the colour was evident in the in- 
terior of the gland, although only around the large vessels which were 
inclosed in the cellular tissue of the capsule of Glisson ; no change of 
colour was produced in the bile, and a very slight one only in the milk. 
In the testicle, salivary and pancreatic glands, and more especially in 
the cellular tissue of these parts, the colouring was more distinct. The 
spleen evidenced no change of colour, the suprarenal capsules scarcel 
a ny, and none was produced in the muscles except at the parts where 
the bundles of muscular fibre were enveloped in fibrous membrane. The 
nerves became green externally, but this was dependent on the cellu- 
iar membrane which surrounded them ; the nervous substance itself, 

a nd the brain and spinal cord, displayed not the slightest alteration of 



of th 

The colour of the bone also remained unchanged. 

The reason 

ese differences is perhaps that the prussiate of potash is de- 

composed in some tissues so as to render its detection by chemical 

* Meckel's Arcliiv. t. iii. 1817, p. 485. 

i ' 

■ II 






tests impossible, for it must be distributed with the blood equally to ail 



delphia instituted,* seem to be opposed to the results of Mayer's experi- 
ments, and of all those hitherto mentioned. They seem to be in favour 
of the opinion of absorption being performed chiefly by the lymphatics. 
But they are not conclusive. The Academy found that after a solu- 
tion of prussiate of potash had been injected into the peritoneum or in- 
testine, the addition of a salt of iron thirty-five minutes or more after- 
wards to the chyle produced in the majority of cases a distinctly blue 
colour, while mostly a slight tinge was also produced in the serum of 
the blood and in the urine. The interval of thirty-five minutes is much 
too great; the blood and urine ought to have been examined, as in 
Mayer's experiment, a few minutes after the prussiate of potash was in- 
troduced. As these experiments were performed, they merely prove 
that chemical agents are absorbed by the lymphatics as well as by the 



one ounce of the solution of prussiate of potash, the experimenters found 
two minutes afterwards, when they let the animal bleed to death that 
the salt could be detected in the urine, but not in the serum of the 
blood nor in the chyle ; and nevertheless, the salt could have passed into 
the urine only through the medium of the blood. The commission of the 
Academy in several cases tied the vena portae, and nevertheless nux vo- 

mica introduced into a portion of intestine produced tetanus in twenty- 
three or more minutes ; while in other cases the mere ligature of th 
vena portas produced death, but without tetanus. These experiments 
seem to prove that the lacteals had conveyed the poison into the blood, 
and it is possible for such to have been the case, in the space of twenty- 
three minutes ; but this does not disprove the possibility of direct ab- 
sorption into the blood in a shorter time. Moreover, branches of the 
portal veins of the intestines anastomose with those of the cava.f 
WestrumbJ detected prussiate of potash in the urine two minutes after 
injecting it into the stomach, while the lymph and chyle contained 

none. The ureters had been divided, and tubes fixed in them, from 
which the urine was received. 

Tiedemann and Gmelin have performed numerous experiments with 
colouring matter and salts which are easily recognised or detected by 
reagents. On examining the chyle several hours after colouring mat- 
ters had been given by the mouth, they have never found it tinned 
although the colouring substances were recognised in the blood and 
urine, and had already passed from the stomach into the intestine. In 

* Philadelph. Journ. N. 6. Froriep's Not. N. 49. 

t See page 185 

± Meckel's Archiv. vn. 525, 540. 




very numerous experiments it was but a few times only that some por- 
tion of the salt taken into the stomach could be detected in the chyle : 
m a horse to which some sulphate of iron had been given it was detect- 
ed afterwards in the chyle; and once in a dog which had taken prussiate 
°f potash this salt was detectible in the chyle, but in a second experi- 
ment this was not the case ; sulphocyanate of potash given to a dog was 
also once detected in the chyle. The objection, that the substances might 
be already all absorbed, is not tenable ; for the intestine still contained a 
considerable quantity of them. These results, which, from the accuracy 
w ith which the experiments were performed, can be in great measure 
depended upon, agree with those of the experiments made by Halle* and 
Magendie.f On the other hand, they are opposed to those 


of Martin Lis- 
Viridet and 

Mattel also assert that they have observed a yellow or red colour in the 
chyle after food consisting of yolk of eggs or red beet had been taken. 

Fodera § filled a portion of intestine in a living animal with solution of 
P r ussiate of potash, tied it in two places, and then dipped it in a solution 
of sulphate of iron ; the lacteals and veins became blue. Schroeder Van 
der Kolk, on repeating this experiment, perceived the blue colour in the 
acteals only, not in the veins. After the lapse of half an hour, the so- 
ut *on of prussiate of potash in the intestine was not changed in colour, 
So that the sulphate of iron had not in that time permeated all the coats 
or the intestine. This does not absolutely disprove the immediate pass- 
age of substances into the blood ; for the small quantities of the salt 
which would enter the blood are immediately carried onwards by the 
circulation, while the motion of the chyle in the lacteals being propor- 
tionally slow, foreign matters absorbed with it would be more exposed 
to the test. Besides, a blue tint is exceedingly difficult to detect in the 
blood itself, and cannot be recognised with certainty except in the serum 
of the blood. Lawrence and Coates || did not detect the salt in the blood 
before it was perceptible in the upper part of the thoracic duct. 

Several experiments to determine the influence of ligature of the tho- 
racic duct on absorption have been made by Brodie, Magendie, Delille, 
and Segalas. In Brodie's^ experiments, the fatal effects of alcohol and 
Worara poison were still produced, after the thoracic duct was tied. 

Since, however, the thoracic duct has sometimes in animals commu- 
nications with veins, — for instance, branches joining the vena azygos, as 

-and since even a right thoracic duct sometimes exists, 
w hile the absorbent vessels have frequent communications with each 
other, the application of a ligature to the thoracic duct cannot absolutely 
P r event the passage of the poisoned lymph into the blood. 

m the 



Fourcroy's Systeme des Connaiss. Chim. 10. 66. 

Phil. Trans. 1701. 819. 

Recherch. exp. sur Texhalation et ^absorption. Par. 1824. 

Froriep's Not. 77. H Phil. Trans. 1811, 

•j- Loc. cit. 







Emmert has demonstrated the immediate passage of matters into the 
blood, by showing that they do not enter the circulation when the blood- 
vessels are tied. Emmert* tied the abdominal aorta, and then intro- 
duced prussiate of potash and a decoction of angustura virosa into dif- 
ferent wounds in the feet. The prussiate of potash was absorbed and 
detected in the urine, but the angustura had not its usual poisonous 
effects. In another experiment, in which Emmert, after tying the ab- 
dominal aorta, introduced prussic acid into a wound of the foot no 
effects had ensued even in seventy hours ; but, on loosening the ligature 
on the aorta at the end of that time, the symptoms appeared in half an 
hour. Jacobson,t lastly, has shown, that in mollusca, which possess no 
lymphatics, prussiate of potash, nevertheless, finds its way readily into 
the blood from every surface to which it is applied, and is again elimi- 
nated from the blood by the secreting organs, — the lungs, liver, and 
saccus calcareus.J 

The immediate absorption of matters by the capillary blood-vessels is 
proved by all these experiments, but especially by the extraordinarily 
rapid effects of poison ; for it is equally certain that the general effects 
of poisoning depend, not on nervous communication, but wholly on the 
noxious substance entering the circulation. 

All the phenomena which we have detailed might, however, be de- 
pendent on absorption by the lymphatics, if, as some recent writers sup- 
pose, the lymphatics and small veins do really communicate^ But this 
objection may be completely set aside by the known laws of the imbibi- 
tion of animal tissues. 

Imbibition.— Hitherto the passage of matters into the blood has been 
supposed to depend on a peculiar absorbing power of the veins. But it 
can be shown that fluid matters find their way without the aid of this 
imaginary power of absorption into the blood of the capillaries ; and 
from the capillaries they necessarily pass first into the veins, the direc- 
tion in which all the blood of the capillaries moves being from the 
arteries towards the veins and the heart. The primary phenomenon of 
the immediate absorption of substances in solution into the blood is the 
permeation of the animal tissues by the fluids. The property of permea- 

• Meckel's Archiv. i. 1815, p. 178. Schnell, Diss. sist. hist, veneni upas antiar. 
Tub. 1815. Tiibing. Blatter. 3. 1. 1817. 

f Froriep's Notiz. xiv. p. 200. 
^ $ On the subject of absorption by the capillaries and veins, consult Westrumb, Phy- 
siolog. Untersuch. iiber die Einsangkraft der Venen. Hannover, 1825. Tiedemann 
und Gmelin, Versuche liber die Wege, auf welchen Substanzen aus dem Magen und 
Darmkanal ins Blut gelangen. Heidelb. 1820. Seiler und Ficinus in Zeitschrift fUr 
Natur- und Heilkunde, ii. 378. Jaeckel, De absorptione venosa. Vratislar, 1819. Leb- 
kuckner, Diss, utrum per vi Pentium adhuc animal, membran. atq.vasor. parietes mater, 
ponderab. illis applicat. permeare queant, nee ne. Tiib. 1819. Wedemeyer, iiber den 
Kreislauf. Hannover, 1828. 421. Schabel, de effect, veneni rad. veratri albi et helle 
borinigri. Tub. 1819. f See p. 272. 

M 1 



bihty by fluids possessed by tissues even after death, depends upon their 

invisible porosity, and is termed imbibition. This kind of absorption 

being exercised by animal textures wholly devoid of life, may be cor- 

rectly termed the inorganic, in contradistinction to the lymphatic ab- 

Gases, and thin fluids, together with the matters they hold in solution, 
Permeate moist animal textures. Two kinds of gases in contact with the 
two surfaces of a moist animal bladder, one being within it and the other 
external to it, each permeate the bladder till they are equally mixed. 
The bladder having been previously dried and then moistened does not 
prevent this process taking place. A gas will permeate a moist bladder, 
to be absorbed by a fluid within it. This explains how it is that gaseous 
matters can enter into the blood during respiration, without the globules 
°f the blood escaping. The gaseous matters permeate the membranes 
of the lungs, and are dissolved in the blood circulating in the numerous 
capillaries which traverse these membranes, by virtue of the invisible 
porosity of the coats of the vessels, which, nevertheless, have no open- 
ings large enough to admit the red particles of the blood. If a piece of 
moist bladder is tied over a bottle completely filled with water, so that 
the bladder is in contact with the surface of the water, and if some salt 
J s then strewed over the outer surface of the bladder, the salt is dissolved 
by the water which permeates the pores of the bladder, and from this 
water is imparted to the water in the vessel. The primary cause of 
imbibition, or the permeability of animal tissues, is therefore the ten- 
dency which substances have to diffuse themselves uniformly in the fluid 
in which they are dissolved. A salt in solution has a tendency to diffuse 
itself through any other fluid with which it is miscible. Salt water and 
water, for example, when in contact, become uniformly mixed with each 
other. Animal tissues owe their softness to the watery fluids which 
they contain, and which fill their pores. Any matter in solution, there- 
fore, which comes in contact with them will tend to diffuse itself in the 
fluids of the pores, and again, through the medium of these pores, with 
fluids in contact with the opposite side of the membrane, until the dis- 
tribution of the matters dissolved is uniform in the two fluids which the 
membrane separates. There are, however, particular circumstances in 
which the process of imbibition is accelerated by attraction, and by the 
action of capillary tubes. The latter is the case when a dry animal tex- 
ture is moistened, in which case the capillary attraction of the empty 
pores must favour the entrance of the fluid. The first case is displayed 
ln the phenomenon of endosmose and exosmose, first discovered by Par- 
r ot, and farther investigated by Porret, Dutrochet, and others. If a so- 
lution of any salt, or of sugar, is poured into a glass tube closed below 
by a piece of bladder, the particles of the solution permeate the pores of 
the bladder, but do not pass through it. If the tube thus filled is placed 

R 2 









are homogeneous. 

in a vessel containing distilled water, the fluid gradually rises, and some- 
times to the extent of several inches, within the tube, and by proper 
tests it is found that at the same time a portion of the solution has found 
its way from the interior of the tube to the water external to it. The 
elevation of the level of the fluid in the tube continues till the two fluids 

If the tube contains water, and the exterior vessel 
the saline solution, the water sinks in the tube. If both vessels contain 
solutions of different salts, but of the same density, the level of the fluids 
does not alter, but the two salts become equally mixed. If, on the con- 
trary, one solution is more concentrated than the other, the quantity of 
the more concentrated one becomes increased. The same phenomena 
are observed when, in place of the bladder of an animal, porous mineral 
substances are used. Two explanations of the phenomena have been 



tween the particles of a saline solution a compound attraction is in play, 
consisting of the mutual attraction of the salt and the water for each 
other, of the attraction between the individual particles of the water, 
and of that between the individual particles of the salt. This compound 
attraction is supposed to be more powerful than the simple attraction 
between the particles of water solely.* The second explanation is the 
following : the animal bladder, inasmuch as it is porous, may be viewed 
as a system of capillary tubes which exercise an attraction on the fluids, 
which have a tendency to mix with each other, through the medium of 
the water which fills the pores. If, now, it be imagined that one of the 
fluids is more strongly attracted by the tissues of the bladder than the 
other, it will, of course, be longer retained in its passage through the 
pores ; and the level of the fluid which passes through most quickly will 
necessarily fall in the vessel that contains it, while the level of the 
former will rise until the increasing pressure of the rising column of 




Dutrochet has named the phenomena which we have described 
dosmose" and « exosmose," according as the quantity of the one or of the 
other fluid increases under different conditions. In the direct passage 
of matters in solution into the capillaries and the blood, endosmose with- 
out doubt takes place, and not merely simple imbibition. Dutrochet has 
demonstrated this by experiment. A portion of the intestine of a young 
fowl, half filled with a solution of gum, sugar, or common salt, and tied 
at both ends, was placed in a shallow vessel filled with water, when it 
soon became filled to distension. If, on the contrary, the intestine con- 
tained pure water, and was immersed in sugared water, it became gra- 

* Berzelius, loc. cit. p. 134. 

f Biot, Experimental- Physik, translated into the German by Fechner, i. p. 384. See 
also Poisson, in Poggendorf's Annal. xi. 134. Fischer, ibid. 126. Magnus, ibid. x. 
153 ; and Wach, Schweigg. Journal, p. 20. 





dually more lax, and the fluid in the intestine was afterwards found to 
contain sugar.* 

Dutrochet's hypothesis, that electric action is connected with these 
Phenomena, has not been confirmed. It does not also constantly happen 
that the denser fluid attracts more of the thinner than the latter does of 
e former : in the case of gases especially, the contrary is seen to be 
sometimes the case. But the chemical constitution of the fluid, and its 
Physical and chemical relation to the animal membrane which it per- 
meates, seem to have an important influence on the phenomenon. Di- 
u te alcohol kept in bladder becomes more concentrated, the water 
alone evaporating ;t and it has been found that if a portion of the intes- 
*ne of a fowl filled with a watery solution of acacia gum and rhabarbarin, 
a nd tied close, is laid in a vessel containing water, the intestine becomes 
distended, while the rhabarbarin exudes from it. Similar sacks filled 
With a weak solution of sulphate of iron, and laid in solution of ferrocy- 
anate of potash, became distended in consequence. of the endosmosis of 
J e water of the exterior solution, which at the same time acquired a 
ue colour from the salt of iron having passed through the membranes 
*n an outward direction, while the absence of this colour in the fluid in 
the interior of the portions of gut proved that the salt of potash had not 
Permeated them. The phenomenon of the endosmosis of gases, on which 

-IVI. Fflnott i™„ :*,„4.:4...i.~j • . . . _ , ,, a ui j j 

A madder 


^alf filled with atmospheric air being placed under ajar containing car- 
bonic acid becomes more distended ; and if the bladder which is placed in 
the carbonic acid gas contained hydrogen, it becomes distended to burst- 
ing. If, on the contrary, the jar contains the lighter, and the bladder 
the denser gas, the bladder becomes collapsed. 


I wished to know the 

time required for any substance to reach by the way of imbibition the 
superficial layers of the capillaries of a part which is not invested by 
epidermis, so as to enter the circulation. The delicate membrane which 
forms the villi of the intestines in the calf and ox contains capillary 
blood-vessels, although the villi themselves measure only ^th of an inch 
111 diameter. From this measurement we can conceive to what depth 
fluids must permeate to reach the capillaries of any membrane free from 
e piaermis. Having put into a glass vessel with a very narrow neck some 
solution of prussiate of potash, I tied over it in one experiment the uri- 
na *y bladder of a frog, in another the lung of the same animal, then with 
a hair-pencil applied to the surface of the soft membrane some solution 

-Dutrochet, L'agent imm£diat du mouvement vital. Paris, 1826. Nouv. Rech. sur 

endosmose. Paris, 1828. [See also the article Endosmose in the Cyclopaedia of Ana- 

t See experiments of Staples in Kastner's Arch, fur Chemie, Bd.iii. H. 1 — 3. p. 282. 
t Amer. Med. Journ. vol. vii. Froriep's Not. N. 646\ 


1 1 i 



(the muriate) 

glass, so that the solution of prussiate of potash came in contact with the 
inner surface of the membrane. A second of time had not elapsed when 
a pale blue spot formed, and soon became more distinct. It appears, 
therefore, that substances in solution permeate a membrane of the thick- 
ness of the stretched bladder of a frog in detectable quantity within a 
second of time. The membrane forming the frog's bladder consists of 
several layers, and is very much thicker than the organised membrane 
which forms the intestinal villi. We may therefore safely admit, that 
substances in solution permeate in detectible quantity a membrane not 
covered by epidermis, so as to reach the first layer of capillaries, and 
thus to enter the circulation in a shorter time than a second. Now the 
blood, according to Hering's calculation, circulates through the whole 
body in half a minute, and, according to others, in from one to two mi- 
nutes ; consequently we may suppose that a detectible quantity of any 
substance in solution, which comes in contact with a membrane free from 
epidermis, may be distributed through the circulating system in from 
half a minute to two minutes. 


The narcotic poisons act, it is true, by abolishing 

the nervous energy, but, when applied locally to the nerves, their effects 
are only local. I held the nerve of a frog's leg, which was separated 
from the body, in a watery solution of opium for a short time, and that 
portion of the nerve lost its irritability, i. e. its property of exciting 
twitchings of the leg when it was irritated ; but below the part that 
the poison had touched the nerve still retained this function. Opium, 
therefore, produces a change in the nervous matter itself; but the in- 
fluence is local, and is not propagated through the nerves, so as to produce 
general poisoning. Frogs are very sensible to the effects of opium; and 
nevertheless, if the leg of a frog is separated from the body, the nerve 
only being left to maintain the connection, and is then placed in a solu- 
tion of opium, and kept there for several hours, the animal suffers no 
narcotic influence ; provided, however, that it is so confined, that in its 
struggles it cannot throw any of the fluid over its body. 

These experiments, as well as many others, instituted by well-known 
physiologists, prove that, before narcotic poisons can exert their general 
effects on the nervous system, they must enter the circulation. Dupuy 
and Brachet indeed maintain that animals cannot be destroyed by nar- 
cotic poisons introduced into the stomach, if the nervus vagus has been 
divided on both sides, or, at least, that they do not die so soon. But in 
thirty experiments on mammalia, which M. Wernscheidt performed un- 
der my direction, not the least difference could be perceived in the ac- 
tion of narcotic poisons introduced into the stomach, whether the nervus 
vagus had been divided on both sides or not, provided the animals were 
of the same species and size. 




The rapid action of the greater number of narcotic poisons is perfect- 
ly explicable by the facts above detailed respecting absorption by imbi- 


ion. Prussic acid, however, exerts its influence in a much shorter 

time than would be required for it to enter the circulation through the me- 
dium of the capillaries, which, as we have said, is half a minute, or two 
minutes. The spirituous solution of extract of nux vomica, also, intro- 
duced in sm^l quantity into the mouth of a young rabbit, produces im- 
mediate death ; whereas when applied to a nerve at some distance from 
he brain, — for instance, to the ischiadic nerve, — it produces no 



e d, does not exert its poisonous influence when applied merely to a bare 
nerve. The rapid effects of prussic acid can only be explained by its 
possessing great volatility and power of expansion, by which it is enabled 
diffuse itself through the blood more rapidly than that fluid circu- 


e s, to permeate the animal tissues very quickly, and in a manner in- 
dependent of its distribution by means of the blood, and thus to produce 
he peculiar material changes in the central organ of the nervous system 
m ore quickly in proportion as it is applied nearer to it. 

Passage ofingesta into the secretions. — The rapidity with which fluid 
Matters are imbibed into the capillaries, and distributed through the 
body by the circulation, explains completely the quick reappearance in 


e urine of substances which have been taken into the stomach with 

tne food, without the need of having recourse to the barbarous notion of 
secret passages existing between the stomach and kidneys. According 
to Westrumb, soluble salts find their way into the urine in from two to 
ten minutes after they are taken into the stomach ; for, when this 
time had elapsed after giving prussiate of potash to an animal, he was 
able to detect it in the urine which he collected immediately from the 
ureter, Stehberger's experiments, however, prove that the reappearance 
m the urine of substances taken with the food ordinarily requires a much 

longer period. 

yf chyle. —The matters which pass by imbibition through 

the walls of the capillaries into the blood must, however, be in solution ; 

hey must not consist of globules. This condition alone shows that the 

digested matters, and the chyle which contains globules, cannot find 

their way by imbibition into the capillaries and the 

venous blood. 


chyle i n the intestinal and portal veins. But the chyle could not have 
entered the blood through the walls of the capillary vessels; for, if that 
w ere the case, the corpuscules of the blood in the capillaries would like- 
Wxs ebe able to escape from them. Perhaps the streaks of chyle observed 
y these physiologists were derived from the communications which are 
upposed, although not yet proved, to exist between the lacteals and 
the small veins. 




Endosmosis, however, does not explain the absorption of all fluids by 
the animal tissues. If the fluids of the tissue itself are more concen- 
trated than those to be absorbed, such as fluids collected in the pleura, 
or lungs, the passage of the external fluids into the parenchyma will, ac- 
cording to the laws of endosmosis, take place more readily than the 
passage of the fluids of the tissue outwards. But if, on the contrary, 
the external fluid is equally concentrated with that contained in the 
tissue, the two fluids ought, according to the laws of imbibition, to pass 
through the membrane in both directions with equal rapidity, so that the 
quantity of both fluids would remain the same ; and, if the fluid of the 
tissue is the less concentrated of the two, it will exude in greater quan- 
tity than the external fluid will be absorbed, so that the quantity of the 
latter will be increased. Imbibition, therefore, does not explain the di- 
minution of the quantity of fluids by absorption, but only the mingling 
of them, as in the case of poisons applied to the surface of the body, 
&c. For a collection of fluid in the pleura, containing albumen and 
salts in the same state of concentration as these substances exist in the 
blood, would not be diminished in quantity by imbibition alone ; there 
would be merely an interchange of the saline matters contained in the 
external fluid and in the blood, while the bulk of the former would re- 
main the same ; and, if the saline ingredients were in a more concen- 
trated state in it than in the blood, its quantity would even become in- 

The removal of collections of fluids by absorption must be effected in 
many cases either by means of the lymphatics, independently of imbibi- 
tion into the capillaries, or we must suppose that the suction of the 
venous blood towards the heart assists the absorption by the capillaries. 
It is possible that the process of endosmosis may be modified by a pecu- 
liar attraction exerted by the tissues on the fluids circulating in them ; 
an attraction, by the agency of which the fluids in the tissues may be 
retained while the external fluid is absorbed, so that merely absorption, 
and not an interchange of fluids, as is the case under ordinary circum- 
stances, is the result. Water, for example, would have a tendency to 
diffuse itself in the blood of the capillaries ; but the blood being under 
the influence of the mutual vital process which is going on between it 
and the capillary vessels, would have no tendency to diffuse itself in the 

The red particles of the blood have, as we have already seen/ 


a great affinity for water, and in their passage through the capillary 
vessels they may contribute to cause its absorption. 

Absorption by organic attraction. —The question whether the blood in 

the capillary vessels, or these vessels themselves, exert on certain sub- 

stances an attraction which differs in its nature from any accounted for 
by physical laws, is quite distinct from the one above discussed. There 


See page 105. 




is only one part of the body in which this kind of attraction certainly ex- 
ists, and that is the capillary system of the placenta. The existence of 
J ymphatics in the placenta and umbilical cord being quite problematical, 
the transmission of nutritive fluids from the mother to the child must 
be effected by means of the capillary vessels of the placenta. There is 
no direct communication between the vessels of the mother and those of 
the foetus, the sole mode in which the uterine arteries terminate is by 
becoming continuous with the radicle uterine veins ; and, on the other 
band, the foetal arteries of the placenta have no other mode of termi- 
nation than in the commencing foetal veins of the same part. Weber* 
bas given a very interesting description of the mode in which the pla- 
centa and uterus are connected. The finest ramifications of the placen- 
tal vessels are distributed in the tufted processes on the maternal sur- 
face of the placenta. The arteries ramify in the tufted villi, and termi- 
nate at the extremities of the villi by direct inosculation with the radi- 
cles of the placental veins. Bundles of these tufts of villi project into 
the cavities of the large veins, in which the maternal blood flows on the 
mner surface of the uterus. From this arrangement of the tufts, and from 
the delicacy of the coats of the uterine veins, the foetal blood circulatin o 
through the capillaries of the placental tufts is freely exposed to the ac" 
tion of the venous blood of the mother, and probably attracts from it 
some of the matters dissolved in it. 

In the endosmosis which undoubtedly takes place between the foetal 
and maternal blood, more matter is received by the foetal blood than is 
given in exchange by it to the blood of the mother. It is an organic 
and vital endosmosis totally different in the laws which regulate it from 
the chemical process of imbibition described by Dutrochet. In rumi- 
nating animals the tufts or villi of the cotyledons of the ovum are not 
imbedded in the veins of the uterus, but, like roots in the ground, in 
sheath-like cavities, or tubes, hollowed in the substance of the uterus. 

All these excavations in the uterus are lined with capillaries of the ma- 
ternal vessels ; while the capillaries of the foetus, which have no commu- 
nication with those of the mother, are distributed upon the tufts of the 
cotyledons. Here the matters which are to be absorbed by the capilla- 
ries of the foetus must first be secreted by those of the mother. 

Does the action of 

It is still matter of doubt 

whether the absorption of fluids into the capillaries by means of imbibi- 
tion is aided by the motion communicated to the blood in the veins, and 
thence to that in the capillaries, by the sucking action which the heart 
exerts in the dilatation of its cavities. The motion of the blood, how- 
ever, must be so far favourable to imbibition, as it removes what has 
already been absorbed, and thus renders constant the cause of the en- 
dosmosis, — namely, the tendency of substances to diffuse themselves 

* Hildebrandt's Anatomie, Bd. iv. p. 496. 

ii -. 




through fluids till equally distributed, If the same portion of blood 

constantly exposed to this action, imbibition would after a time 
necessarily cease. 

Influence of gah 

Fodera* has observed that ab- 

sorption, or imbibition, is accelerated by the action of galvanism. He 
injected prussiate of potash into the pleura, and sulphate of iron into the 
abdomen. Usually five or six minutes elapse before these two substances 
combine ; but their combination was instantaneous when a slight gal- 
vanic current was passed through the diaphragm. The same phenome- 
non is said to occur when one fluid is introduced into the urinary blad- 
der, the other into the abdomen, or one into the lung, the other into the 
pleura. The nerves have no influence on inorganic imbibition ; there 
was, in my experiments, no perceptible difference in the absorption of 
poisons whether the nervus vagus had been divided or not. 

Changes produced in the matters absorbed. — Matters which find their 
way from the intestines into the circulation by permeating the coats 
of the capillaries, do not pass directly from the intestinal veins into 
the vena cava, they circulate through the liver before reaching the 

general circulation. Ma 

has observed, that in their transit 

through the liver the properties of many substances are altered. Thus 
if a grammef of bile, or a considerable quantity of atmospheric air 
are injected into the crural vein, immediate death is the consequence ; 
while, if they are injected into the vena portae, the animal suffers no ill 
effect. Many substances undergo a change in the intestines themselves. 
Thus the poison of the viper, when taken into the stomach, produces, 
according to Redi and Mangili,^; and Dr. Stevens,§ no poisonous effects; 
and the saliva of hydrophobia, according to Coindet,|| does not exercise 
its infectious property when taken into the alimentary canal. 

Effect of plethora 


sion of the blood-vessels, with an excess of fluid, diminishes the activity 
of absorption. By the injection of water into the veins, the absorption 
of foreign substances by the organised membranes was prevented • but 
after taking some blood from the animal, absorption commenced with 
the usual phenomena. Venesection, on the contrary, accelerated the 
process; so that phenomena, which ordinarily did not ensue till after 
two minutes, appeared in half a minute. Absorption is most rapid from 
the mucous membranes, from serous membranes, and from wounds ; it 
is much slower from a membrane covered with epidermis. 

Absorption by the skin. — The most external layer of the organised cutis 
seems indeed to possess a very feeble absorbent power : this may per- 
haps arise from its secreting horny matter. Colouring matter, consist- 
ing of granules or grains of powder from an explosion, having found 

* Journ. de Physiol, iii. p. 35. 

t Meckel's Archiv. iii. 1817, p. 639. 

|| Froriep's Notiz. 1823, Sept. 170. 

t About 15J grains avoirdupois 
§ On the Blood, p, 137, 





their way into cracks of the skin, remain during the entire life without 
being dissolved or absorbed. Nitrate of silver given internally for a 
considerable time, imparts a blackish slate-colour to the skin, probably 
from a chemical combination being formed between the silver and the 
animal matter. The skin covered with epidermis, however, is certainly 
endued with an absorbing power ; but the substances to be absorbed 
must be either in solution, or readily soluble in the animal fluids. The 
subject of absorption by the skin is important, on account both of the 
frequency with which foreign substances come in contact with it, and 
f rom its being adapted to the application of medicinal substances. Seiler 
and Ficinus found that when the feet of horses had been moistened 
with solution of oxide of lead in liquor potassa?, this substance was detecti- 
ve in the blood and chyle. 

All metallic preparations rubbed into the skin have the same action 
as when given internally, only in a less degree. Mercury applied in 
this manner cures syphilis, and excites salivation; tartrate of anti- 
mony, according to Letsom and Brera, excites vomiting; and arsenic 
exerts its poisonous effects. Vegetable matters also, if soluble, or al- 
ready in solution, exert their peculiar effects through the medium of the 
skin. Haller states that white hellebore laid upon the abdomen excites 
vomiting, and that violent purging is produced by washing the feet with 
a decoction of either the white or the black hellebore. Sabadilla seeds 
applied to the skin were found by Lentin to excite most violent cramps, 
and when rubbed on the abdomen to cause purging. Cantharides applied 
to the skin excite strangury ; and narcotics thus applied produce their 
peculiar effects. Camphoi 

expired from the lungs ; oil of turpentine by the violet smell of the 
urine; mercury in the blood, saliva, urine, and milk, according to Bloch, 
Autenrieth and Zeller, and Canter, and in the bones also, according to 
Fricke ;f prussiate of potash, rhubarb, and madder, in the blood, urine, 
&c; each of these substances having in the respective cases been applied 
to the skin. But the action of all medicinal substances and poisons 
applied to the skin is much more powerful if the cuticle has been pre- 
viously removed. 

It has long been a contested question whether the skin covered with 
its epidermis has the power of absorbing water, and it is a point difficult 
to determine, because the skin loses water by evaporation. 

The epidermis is certainly hygroscopic, and swells when placed in 
water. The experiments of Falconer, Alexander, and others, which 
consisted in weighing the body and the water in baths, appear to me 
unworthy of dependence. SeguinJ and Currie§ could discover no in- 


On this subject consult Westrumb, Meckel's Arcbiv. 1827 ; and Sewall, ibid 
t Horn's Archiv. 1826. 459. 

Ann. de Chimie, t. xe. 185 ; t. xcii. 33. Meckel's Archiv. iii. p. 385. 
Med. Reports^ ch. xix. 

ii. 146 





crease of weight when the whole or part of the body was immersed in 
water ; and those experiments in which colouring matter or prussiate of 
potash dissolved in the water of a bath could afterwards be detected in 
the urine, by no means prove that the water was absorbed. Saline sub- 
stances can permeate a membrane both sides of which are in contact 
with water, without the level of the water on either side undergoing any 

[M. Edwards* has proved most clearly that this absorption of water 
by the surface of the body takes place in the lower animals very 
rapidly under certain circumstances. Not only frogs, which have a thin 
skin, but lizards, in which the cuticle is so very much thicker than in 
man, after having lost a great part of their weight by being kept for 
some time in a dry atmosphere, were found to recover both their weight 
and plumpness very rapidly when immersed in water. Merely the tail, 
posterior extremities, and posterior part of the body of the lizard were 
immersed, but the water absorbed was distributed throughout the sys- 

tem. M 


the skin of man, if the scaly skin of the lizard possesses it. The re- 
sult of Seguin's experiments, namely, that there was a loss of weight 
during the immersion in water which was equal to the loss by pulmonary 
perspiration under other circumstances, is explained by M. Edwards, by 
supposing that the absorption and transudation by the skin were equal, 
so as to balance each other. M. Seguin supposed that neither took place! 
Two causes are found to exert a great influence over these two func- 
tions of the skin in the lower animals : 1st, the quantity of fluid al- 
ready in the body ; and, 2ndly, the temperature of the water in which 
it is immersed. Fulness of body renders absorption less, and lowness 
of temperature diminishes the exudation. To render absorption by the 
human skin perceptible, the exudation must not only be depressed be- 
low the amount of the absorption by the skin, but the absorption must 
be so great as to balance the loss by pulmonary exhalation. This can 

also that there is a perceptible 


seldom happen. M 

absorption by the skin of the lizard in humid air ; and in an experfmlnt 

made on several Guinea pigs kept in a moist atmosphere, he found that 

the average weight of their evacuations exceeded the loss in the weight 
r y _. „,_ Qn comparing thig resulfc wkh the ]oss of ht of 

Guinea p lgs kept in a dry air, he was inclined to attribute the excess of 
weight of the evacuations to the absorption of watery vapour. But it is 

of the animals. 

the skin in a moist atmosphere than in water, and it must be much less 
abundant, more particularly in warm-blooded animals ; for, their tempe- 
rature being generally higher than that of the surrounding air, the air 
becomes rarefied around them, and thus more susceptible of imbibing 


* On the influence of physical agents on life, pp. 181. 189. 



The absorption of different kinds of gas by animal tissues, as in the pro- 
cess of respiration, and even by the skin itself, is placed beyond doubt by 
"»e experiments of Abernethy, Cruikshank, Autenrieth, Beddoes, and 


s in 

artigny. In these cases, of course, the absorbed gases com- 

«*e with the fluids, and lose the gaseous form. Several physiologists 
^ave observed an absorption of nitrogen by the skin : Beddoes says that 

e saw the arm of a negro become pale for a short time when immersed 
*n chlorine ; and Abernethy observed that when he held his hand. _ 
0x ygen, nitrogen, carbonic acid, and other gases contained in jars over 
Mercury, the volume of the gases became considerably diminished. 

Interstitial absorption.-— It is still a matter of doubt whether the ab- 
sorption which goes on in the substance of the different textures of the 

°dy is chiefly performed by the blood-vessels, or by the lymphatics. 

n many parts, however, in which the existence of lymphatics has never 
been demonstrated,— for example, in the bones,— there is marked evi- 
dence of absorption going on. 

In many other cases in which matters are absorbed from parts known 
o possess lymphatics as well as blood-vessels, it is quite uncertain into 
hich order of vessels these matters are first received. This is the case 
m the following instances: the reabsorption of the colouring .uaicer 
the bile deposited in the different tissues in jaundice, and the absorp- 
«>n of accumulated secretions, such as bile and urine, into the circu- 
ation ; the wasting of the thymus gland during the period from infancy 
to the twelfth year ; the disappearance of the fat from the body gene- 
rally in persons fasting, in consumptive persons, after great losses of 
the fluids of the body, and in animals during hybernation ; and the fre- 



These cases of 

absorption are not all of the same kind. The true interstitial absorp- 
tion of organised tissues, in which the particles of the tissue which fill the 
meshes of the capillary network are removed, must be distinguished from 
the cases of the absorption of fluids, which do not form part of the tissue, 
and have therefore no mutual vital action with the blood-vessels. In the 
Process of interstitial absorption, as it occurs in the atrophy of the tail 
ot the tadpole, and of the pupillary membrane in the foetus, and in the 
aevelopement of cells in the bones, the most essential circumstance, 
Perhaps, seems to be the solution of the particles which occupy the 
meshes of the capillary system. The matter when dissolved may be 
removed by imbibition into the currents of blood, or, except in the 
ease of the bones, by absorption by the lymphatics. Of all organised 
parts, the bones present the phenomena of interstitial absorption in the 
™ost remarkable degree; their cells are developed in the child long 
after the bone is formed, and increase in size by the agency of the same 
process. The diploe of the cranial bones disappears in old age, and the 
bones become thinner. The frontal and sphenoidal sinuses are deve- 


I : 




contact with living 


loped in the period of youth. Parts, however, which are not organised, 
but are only in connection with an organised matrix,— for example, the 
roots of the teeth,— are also subject to absorption. The roots of the 
first teeth disappear at the time of the change of the teeth ; and Soem- 
mering* has observed that they become soft, probably in consequence of 
solution of their component matter. In caries, also, which depends on 
an abnormal combination of their components, the teeth are acted on 
by the fluid of the mouth and softened. It is still unknown whether 
necrotic portions of bone which remain long in 
textures, diminish in size. 

When, in consequence of diseased states of the blood, of paralysis, or 
other causes, nutrition is less active, the interstitial absorption is no 
longer counterbalanced, and the part wastes. Whether in phthisis the 
muscular fibres themselves waste, or merely the cellular membrane in 
their interstices, is uncertain. Their muscles, however, such as the 
platysma myoides, and some muscles of the external ear, seem really to 

In paralysis the wasting of the muscles is more frequent ; and 
Schroeder Van der Kolk has even observed their conversion into fat. 
Cartilage, bone, brain, and nerves, according to Desmoulins' and Schroe- 
der's researches, do not waste in phthisis. When the cause of atrophy 
is general, the tissues are absorbed in the following order : fat, cellular 
tissue, muscles, bone, cartilage, and tendon. Long-continued pressure, 
by putting a stop to nutrition, may cause every tissue to be absorbed. 
The mode in which pressure acts in causing the absorption of bone, is, 
however, a problem still requiring solution ; for if the cessation of nu- 
trition in consequence of the pressure were the sole cause, the articular 
heads of the bones of the lower extremities ought also to be absorbed. 
Perhaps a swelling affecting all surrounding parts — an aneurysm, or 
fungus, — excites inflammation of the bone, as well as of other parts ; 
and bone when inflamed becomes softened, and is consequently more 
readily susceptible of absorption when its nutrition happens to be inter- 
rupted by any pressure. Caries, however, is not produced in these 
eases.f It is a well-known fact that iodine favours the wasting and 
absorption of organised tissues. 

b. Of exhalation and exudation. 


stances which have been taken up into the circulation, and which are 
then distributed through the body with the blood in their original state, 
or more or less altered, are afterwards eliminated from the system by 
the process of imbibition and endosmosis. Prussiate of potash, having 

* Vom Bau des Menschlichen Korpers, i. § 226 u. 233. 

t On this subject consult Schroeder V. d. Kolk in Luchtmann, De absorptionis 
sanae et morbosee dibcrimine. Traj. ad K. 1829. 







entered the circulation by endosmose, permeates the tissues which form 
ne surfaces communicating with the exterior, according to the same 
aws, and becomes mingled with the natural secretions. In this way it 

soon appears again in detectible quantity in the most various secreted 

wuias • m tho .,*.;,,,. r_.. • ' ».-__ •. , 


umb m from two to ten minutes after its introduction into the body. 
m fte blood impregnated with prussiate of potash, and the fluid contained 
J* the cavities of a secreting organ,— for example, the urine in the tubuli 
nnifen of the kidney,— are able, in accordance with laws purely phy- 
sical, to impart to each other the substances that they contain in se- 
ction until these substances are equally diffused in both. In jaundice 
a most all the internal organs, as well as the secretions, become im- 
pregnated with the colouring matter of the bile, which is contained in 
the serum of the blood. 

Those natural or accidental ingredients of the blood which are ca- 
pable of assuming the gaseous form may, unless they are retained by 
some special attraction exerted on them by the tissues, evaporate from 
«e free surfaces of the membranes of the body. 
When pressure favours their passage through the pores of the animal 
embranes, even fluids must, in accordance with physical laws, force 
*eir way into the free cavities filled with gas or vapour ;— hence the effu- 
sion of fluids in the animal body after death as the effect of mere gra- 
vitation ; serum, at first pure, afterwards with the colouring matter of 

it> permeates the tissues, and may collect in the 

m 9+ m » 

bJ ood dissolved 

different cavities; the bile exudes from the gall-bladder, and colours 
yellow the parts which are in contact with it. During life, absorption 
effected by an attraction of a vital nature counterbalances this trans- 
udation of fluid through the membranes of the body ; but in disease 
different causes destroy the balance of the two processes, and then 
the water, with the animal matter and salts dissolved in it, collects in 
the cavities of the body and in the cellular membrane, and gives rise to 
the appearances of anasarca or oedema, and albuminous urine. Oblite- 
ration of the great venous trunks of the viscera or of the extremities 
gives rise to exudation of albuminous fluid into the surrounding serous 
sacs or into the cellular membrane, particularly of the inferior extremi- 
ties ; and artificial dropsy of the cellular membrane may be produced, as 
Souillaud has shown, by tying the great venous trunks. The dropsies 
occurring in consequence of degeneration of the viscera may possibly be 
also partly dependent on the circulation through the viscera being ob- 
structed. The exudation of the fibrinous fluid in inflammation might 
oe explained in the same way ; but the quality of the exuded matter 
depends on other causes. 

■Exudation during life. — The foregoing observations Avould seem to 
show that the exhalation of vapour, and exudation of fluid, are, even in 




the living body, the result of the purely physical laws of imbibition, en- 
dosmosis, and pressure. But that is not the case. If exudation during 
life was solely under the influence of these physical laws, all the ingre- 
dients of the fluids would escape equally ; but the matter which per- 
meates the tissues, and is exhaled or exuded, often consists of a part 
only of the substances which are contained in solution in the blood. Thus 
in inflammation the matter which exudes through the membranes is the 
fibrin which the serum of the blood holds in solution ; while, on the con- 
trary, in dropsies, — such as are produced, for example, by obstruction to 
the return of venous blood, — the fibrin does not exude; the exudation is 
merely an albuminous fluid. There must, then, under ordinary circum- 
stances, be some force in action which prevents the escape of fibrin from 
the vessels, and which in inflammation is rendered inert, — some affinity 
or attraction which the parenchyma possesses for the fibrin, but not for 
the albuminous serum, which therefore in anasarca is allowed to escape. 
At the commencement of inflammation, as observed in a wound, or after 
the application of a blister, serum merely is effused; when the inflamma- 
tion becomes more violent, the fibrinous part of the blood also exudes. 

It is most probable that there are similar differences in the exhalation 
of fluids in the gaseous form, for instance, from the skin ; and that not 
every part of the fluids of the body which is capable of assuming the 
form of vapour, is really exhaled from the surface of the membranes. 

Secretion. — The elimination of many substances from the blood cannot 
be explained according to |the laws of endosmosis. The urea, for ex- 
ample, which has been proved to exist already formed in the blood 
itself, * is nevertheless excreted by no other part of the body than the 

Other excretions, formed of components of the blood, are formed only 
under certain local conditions. This is the case with the menstrual 
flux, which, according to the observations of Lavagna, Toulmouche, 
Brande, and myself, contains no fibrin; the clots which form in it are soft, 
and consist principally of red particles alone. Brande is certainly wrong 
in saying that the menstrual fluid is merely a concentrated solution of 
the red colouring matter of the blood; I have found red particles in it 
perfectly unchanged in appearance. It must therefore be supposed that, 
at the period of menstruation, the texture of the vessels of the uterus 
becomes so loose as to allow the escape of the red particles. There are 
no open mouths of veins in the uterus any more than in other parts of 
the body. 

In the cases also in which the blood itself escapes slowly from the 
surface of membranes, by what is called exhalation, secretion, or « dia- 
pedesis," there is more than a simple secretion or transudation; the coats 
of the vessels must be changed in texture, and in many cases, as for ex- 

* See page 151. 



ample in haemoptysis and in the bloody expectoration which accompa- 
nies inflammation of the lungs,—* not in all, there is rupture of the mi- 

nute vessels or capillaries. 


render it probable that, under particular circumstances, the colouring 
patter of the red particles may, even in living animals, be dissolved in 
tne serum, and thus give rise to a coloured effusion. Having injected 
a considerable quantity of warm water into the veins of horses, he found 
that exudation of serum, of a red colour, took place from the nostrils, and 
into the abdominal cavity. The colouring matter of the red particles is, 
*t is known, soluble in water ; and in scurvy, purpura, and after the bite 


A certain 

talented physician supposes the exhalation of blood or " diapedesis," of 
which we have spoken above, to be a mere exudation of a solution of 
colouring matter without any entire red particles. This is a difficult matter 
to prove, and until proved cannot be admitted as a fact. Even the bloody 
appearance of the serum of the blood in scurvy may arise, not from 
cruorine being dissolved in it, but from its containing a few red particles 
diffused through it, which is very likely to happen when blood does not 
coagulate firmly. 

The globules of secreted fluids must be supposed to be formed at the 
moment that the secretions are separated from the blood; they could not 
have passed entire through the coats of the vessels. The globules of 
pus, for instance, which are larger than the red particles of the blood, 


cannot be those bodies 

merely changed in some way. They must either be particles of the 
tissue separated from the suppurating surface, or they must be formed at 
the very moment of the elimination of the secretion, as the observation 
of Brugmans and Autenrieth, that pus, when first formed, is a thin and 
clear fluid, would seem to indicate. The elimination, by the kidneys, of 
globules of pus which had found their way into the blood, is quite an 
impossibility; the proximate components only of the pus. in a state of 
solution can be eliminated from the blood, the globules must be formed 
from these components afterwards. 

* Ueber den Kreislauf ; Hanover, 1828; 463. 
t Autenrieth, Physiol, ii. 154. 







Of the Lymph and the Lymphatic Vessels. 



The lymph is the fluid contained in the lymphatic vessels; its appear- 
ance, as observed by Professors Wutzer and Nasse, and myself, is that 
of a transparent pale yellow fluid; it has generally no tint of red, unless 
some of the red particles of the blood are accidentally mixed with it. 
In the frog it is perfectly transparent, and has not even a yellowish 
tint. Lymph is devoid of smell, is slightly alkaline, and has a saline 
taste- The lymph of the intestines, when it contains matter just ab- 
sorbed from the digested food, is always more or less turbid, and has a 
yellowish grey or whitish colour, arising from the presence of a great 
number of globules ; it is then called chyle. 

Analysis of lymph and chyle.— Both lymph and chyle contain albumen 
and fibrin in the state of solution. The fibrin of lymph removed from 
the body coagulates in less than ten minutes. Reuss and Emmert* 
found, by experiment, that 92 grains of lymph of the horse yields only 
one grain of soft coagulum, consequently less than one-third per cent, of 
dry fibrin. The fluid which remained after the fibrin had coagulated was 
evaporated to dryness, and yielded 8f per cent, of dry residue, consist- 
ing chiefly of albumen and chloride of sodium. The fibrin which Reuss, 
Emmert, and Lassaigne obtained from the lymph of the horse, as well 
as that which Nasse and I obtained from human lymph, was quite 
colourless. The fibrin which I procured from the lymph of the fro°- 
had always the same appearance as that from human lymph. The pale 
red colour which Tiedemann and Gmelin ascribed to the lymph, was 
perhaps produced in the lymph they examined by the accidental admix- 
ture of a small quantity of blood. 

The following is the composition of the lymph of the horse, according 
to Lassaigne's analysis : 

^ K at6r ' • 92-500 

Flbrm > 0-330 

Albumen, 5-7S6 

Chlorides of sodium and potassum, with soda and phosphate of lime, 1-434 



Besides the above ingredients, Tiedemann and Gmelin state that the 
lymph contains salivary matter, osmazome, carbonates, sulphates, muri- 
ates, and acetates of soda and potash, with phosphate of potash. 

* Schemes Journal, v. 691. 




The chyle differs from lymph in several particulars. It contains un- 
combmed fatty matter which is not present in lymph. The proportion of 
me solid ingredients is greater in the chyle; Tiedemann and Gmelin ob- 
tained 0-37 parts of dry fibrin from 100 parts of chyle taken from the 
acteals of the mesentery of the horse, while from the same quantity of 
ymph from the lymphatics of the pelvis they obtained only 0-13 parts, 
"e chyle also contains more globules than the lymph, and is more 
opaque. The globules of the lymph are very few in number, and 
utherto have been quite overlooked ; Dr. H. Nasse and I have, however, 
seen them in the lymph of man, and I have seen them repeatedly in the 
ymph of frogs. It appears that hitherto human lymph had never been 
examined. The fluid which Soemmering took from "varices" of lym- 
phatic vessels, did not coagulate, and could not have been lymph. 

Human lymph — The rare opportunity of examining the lymph of the 
human subject occurred to Dr. H. Nasse and myself at Bonn, in the winter 
1832 and 1833. A young man, in the surgical ward of Professor Wut- 
zer, had received, some time previously, a wound on the dorsum of the 
°ot ; and a small opening still remained, which it had been found impos- 
sible to heal. From the opening lymph constantly exuded, and on 
passing the finger along the dorsum of the great toe towards the situa- 
tion of the wound, a quantity of perfectly transparent fluid flowed out 
each time, sometimes in a jet. This was lymph ; for, about ten minutes 

(like a spider's web) 

Being thus enabled to collect lymph in con- 

formed in it. 

Microscopic characters] 

siderable quantity, I was most anxious to know whether it contained any 
globules. All recent anatomists,— Reuss, Emmert, Soemmering, Tiede- 
mann and Gmelin, Brande, and Lassaigne,— have failed to observe them: 
Hewson, however, states that he saw innumerable white bodies, about 
the size of the nuclei of the red particles of the blood, in lymph taken 
from the thymus gland ; but it is doubtful whether this was really lymph : 
in lymph taken from the surface of the spleen, and which had a red tint, 

, On examining the lymph 


Hewson states that he found red globul 

obtained as above described, with the microscope, I perceived that, al- 
though a clear transparent fluid, it contained a number of colourL„„ 
globules, which were much smaller and much fewer in number than the 
red particles of the blood. When the fibrin of the lymph coagulated, a 
ew of the globules were enclosed in the clot; the greater part of them 
remained suspended in the serum. The coagulum, after it has firmly 
contracted, consists of a white fibrous tissue ; and it can be shown dis- 
tinctly that it is formed, not by the aggregation of the globules, but by 
tne coagulation of a substance which was previously in solution. On 
examining, by a high magnifying power, the coagulum of a small quan- 
ity of lymph which had been allowed to coagulate in a watch-glass, we 




could see the globules of the lymph dispersed through the coagulum, 
just as they appeared before in the fluid lymph. It was at the thin border 
of the coagulum that we could best observe the substance which formed 
it and connected together the globules. It was quite homogeneous, 
slightly transparent, and, as far as could be observed, did not consist of 
globules. If it did consist of globules, they must have been much more 
minute than the visible globules of the lymph.* These observations 
prove that, although the lymph really contains globules, the fibrinous part 
of the lymph exists in the state of solution. 

of the ft 

The opportunity seldom occurs for the repetition 

of these observations on the lymph of man ; but, whenever we can pro- 
cure frogs, the lymph of these animals can always be very easily obtained 
in a pure state. The skin of the frog, it is well known, is very loosely 
connected with the muscles ; and the nature of the fluid contained be- 
tween the skin and the muscles is alone sufficient to show that consider- 
able cavities for containing lymph must exist in this situation. If the 
skin of the thigh is divided, care being taken that no large blood-vessels 
are cut, and then separated from the muscles for some extent, a clear 
colourless fluid, of a saltish taste, frequently exudes, but not always. If 
the frog is very large and recently caught, the quantity of the fluid is very 
often considerable. In a few minutes it deposits a coagulum of consi- 
derable size, which is at first transparent and colourless, and afterwards 
contracts until it acquires a whitish fibrous appearance. 

If the lymph is thus collected from a great number of frogs, sufficient 
may be obtained for making a more accurate examination of it. By 
drying the fibrinous coagulum of a known quantity of lymph, and then 
weighing it, I found that eighty-one parts of frog's lymph contain one 
part of dry fibrin, a proportion which seems remarkably large. But per- 
haps we must not attribute much value to an estimate drawn from one 
experiment, made with so small a quantity of lymph. If frogs are kept 
for a long time, their lymph ceases to be coagulable ; and their blood, in 
like manner, then yields little or no coagulum. 

The lymph of frogs recently caught contains, very scantily diffused in it, 
globules, which are about one-fourth the size of the red particles of the 
frogs blood. They are round and not flattened, while the red particles 
of the blood are elliptic and flattened. In dividing the skin of the frog's 
thigh, some blood-vessels are necessarily cut; hence some of the elliptic 
particles of the blood will appear in the lymph when examined with the 
microscope ; their number, however, is so small, that they do not prevent 
the lymph from being perfectly clear and colourless. 

The lymph of the frog and that of man agree so nearly, that, by means 
of that which may be so easily obtained from the frog, we can at any time 
demonstrate at lecture the principal qualities of this fluid. 

* Compare Dr. H. Nasse's account in Tiedemann's Zeitschrift, v. 




Hitherto no medical man could be upbraided if he had never seen 
lymph, although it is so much spoken of by pathologists and physi- 
cians. They have,, indeed, been so ignorant of its nature, that the name 
of lymph has been given to very different fluids. Not merely exudations 
containing fibrin and albumen, but even the secretions of sores and pu- 
riform matters, and especially all matters the nature of which is not ex- 
actly known, have been called lymph. 

In the lymph of the frog it can be seen, even more distinctly than in 
that of man, that the coagulum is formed of fibrin which was previously in 
solution, and that the globules of the lymph have no share in the coagula- 
tion. The albumen of the lymph is coagulated by the ordinary reagents. 
It is remarkable that not only the lymph of the frog is rendered turbid 
by the addition of liquor potassas in large quantities, and that albumen 
is immediately precipitated from the lymph of mammalia on adding 
liquor potassae, but that the albumen is precipitated even from a small 
quantity of the serum of the blood when liquor potassae is added in large 
quantity. The liquor potassae must, however, be quite concentrated. 


The lymph seems to be colourless in 

most parts of the body under ordinary circumstances, but it has some- 
times been seen of a reddish colour; both Ma 
and Gmelin, observed this colour in the lymph of animals which had 
fasted, and in the lymphatics of the spleen the lymph has frequently a 
red tint. This colour of the lymph of the spleen has been observed by 
Hewson, Fohmann, and Tiedemann and Gmelin. Seiler perceived it 
but rarely, and Rudolphi thought it was accidental. I have, however, 
repeatedly examined the spleen of the ox in the slaughter-house, and, 
among the numerous large lymphatic vessels which run on the surface of 
the spleen, have always found some in which the lymph had a dirty red- 
dish colour. Hewson thought that this tint, which is very slight, was de- 
pendent on the presence of some red particles of the blood ; but I am 
rather inclined to believe that it is owing to some of the colouring mat- 
ter of the blood, in the highly vascular tissue of the spleen, having been 

dissolved by the lymph. 

The chyle is almost always more opaque than the lymph of the same 
animal. The opacity of the chyle seems to be dependent on the globules 
that it contains. In mammalia, it is generally whitish, particularly after 
fat or animal food has been taken. In birds, it is not white, and is more 
transparent. The chyle of the thoracic duct has, in the horse, a reddish 
tint which is more rarely seen in other animals. When the red tint 

exists, it 

deepened by exposure to the air. 
Nature and source of the globules of the chyl 

The globules 

of the chyle of mammalia, at least those of the rabbit, cat, dog, calf, 
and goat, which I have myself examined by means of the microscope, 
are not flattened like the corpuscules of the blood; they are globular 







g thei 


Prevost and Dumas found the diameter of the globules of the chyle 
to be YxV-gth of an in ch, that is, something more than one-half the size 
of the red particles of the blood in man.* In examining the globules 
of the chyle by the microscope, I have always mingled with them, on 
the glass plate, some of the red particles of the blood of the same ani- 
mal. I found them in some instances, as in the cat, to be equal in size 
to the red particles of the blood ; in other cases, generally indeed, as 
in the calf, the dog, and the goat,, they are somewhat smaller ; in the 

r size is very various, — all are smaller than the red particles of the 
animal's blood, and the majority of them are very small indeed. In the 
rabbit, some of the globules of the chyle were larger than the red par- 
ticles of the blood, although the majority of them were much smaller, 
not more than a half or two-thirds the size of the red particle. These 
minute globules were not finely divided portions of fatty matter, for I 
had an opportunity of seeing such particles of fatty matter in the chyle 
of a dog fed with butter, and it was evident that the fatty particles 
were quite distinct from the true globules of the chyle. Professor R. 
Wagner's f observations agree with mine, 
ful with reference to the identity of the lymph and chyle globules with 
the nuclei of the red particles of the blood. Tiedemann and Gmelin 
have given us the most complete information regarding the chyle ; with 
their observations I cannot at all compare mine, which are much less 
numerous. One of their statements, however, I must dissent from ; they 
assert very decidedly, that the turbidity and the milky appearance of 
the chyle depend wholly on the presence of globules of fat suspended 
in it. They seem to regard the chyle as an incomplete solution of ani- 
mal matter, in which there are no other globules floating than globules 
of fatty matter. In fact, they state that by agitating the milky serum 
of the chyle with ether which was free from alcohol, they were able 
to render the turbid serum gradually clear. This is a very important 
point; for if chyle is merely a solution of animal matter, and if with it 
no other globules are absorbed into the lacteals than globules of fat, 
there would really be no necessity for the existence of the openings which 
have hitherto been sought for in vain in the villi of the intestines • and 
the coats of the minute lacteals, which form the ultimate net-work, might 
have no larger pores than those to which all animal membranes owe their 
permeability to fluids, and substances in solution. 

But it seems to me to be probable that globules, independent of the 
more finely divided particles of fat, are really taken up from the intes- 
tines into the chyle. On treating the milky serum of the chyle of the 
cat with ether freed from alcohol, in a watch-glass, the serum seemed 
at first to become gradually somewhat clearer ; but there still remained a 

* See E. H. Weber's remarks in Hildebrandt's Anat. t. i. p. 160. 
t Hecker's Ann. 1834; Mailer's Archiv. 1835, 107. 



turbid appearance at the bottom of the watch-glass, even after continu- 
ing the experiment a long time with repeated fresh portions of ether. 
On examining this turbid portion by the microscope I found that it con- 
tained the globules of the chyle quite unaltered. I agree with Tiedemann 
and Gmelin that the chyle becomes more opaque after fat food has been 
taken ; but I cannot allow that all the globules of the chyle are merely 
particles of fat. Even if ether did render the chyle quite clear, this 
would not prove that there were no other globules in the chyle than 
those of fatty matter; for lymph is a perfectly transparent fluid, and yet 
it has globules diffused through it. 

The globules of the lymph must be derived either from particles cast 
off from the tissue of the organs during the process of absorption, or they 
must be formed in the lymph itself after it is absorbed. There are no 
proofs to show that the globules of the chyle are developed in the lac- 
teals. If they are formed in these vessels, it must be in the net-work 
which is contained in the coats of the intestine, and from which the 
larger lacteals arise ; for I have found the globules even in the chyle 
taken from those lacteals which run on the surface of the intestines in 
the calf, in which these vessels, when filled with chyle, are very visible. 
The presence of globules in the chyle might be explained even 
without the necessity of permeation of the coats of the lymphatics, and 
without pores existing, if Doellinger's hypothesis were adopted. Doel- 
linger* supposes that the villi of the intestines are constantly under- 
going solution on their interior, so as to form the chyle of the lacteals, 
while they are reproduced on their external surface by the aggregation 
and apposition of particles from the chyle contained in the intestines in 
the same way as the germinal membrane of the embrj^o grows by the 
apposition of the particles of the yolk. There are facts, however, which 
render this hypothesis improbable. In mammalia the chyle is always 
more or less opaque after a meal, and is thus distinguished from the 
lymph — the product of absorption of other parts of the body. The 
chyle varies, too, according to the nature of the food that is taken. 
The rapidity with which fluids are absorbed from the intestinal canal is 
well known ; and yet it is scarcely possible that they are conveyed into 
the blood solely by being imbibed immediately into the capillaries. Co- 
louring matters, too, have been observed a few times in the lacteals, 
though rarely. The absorption of milk, and consequently of globules 
into the blood, is rendered in some measure probable by a circumstance 
noticed by Schlemm. He has observed that, for a certain time after 
sucking the blood of kittens is sometimes, but not always, of a yellowish 
red colour and separates, when it coagulates, into a red clot and a milk- 
white serum. Rudolphi and I have verified this observation, and it has 

* Froriep's Notiz. i. N. 2. 






case also in young puppies. I have made the experiment but once on 



In young animals it seems, then, that the globules which cause the 
white colour of the milk are really absorbed into the lacteals. All the 
milk, of course, cannot be absorbed in this way; for a portion, as Mayer 
remarks, is coagulated in the stomach. Kastnerf repeated Schlemm's 
experiment without obtaining the same result.! 




The most important researches of earlier writers on the structure of 
the lymphatics are contained in the collection of the works of Mas- 
cagni, Cruikshank, and others, edited by Ludwig. More recently, this 
department of anatomy has been much advanced by the distinguished 
labours of Fohmann,§ Lauth,|| and Panizza.tfl" 

The forms in which the absorbents take their rise may be seen, in prepa- 
rations of these vessels injected with mercury, to be two : 



chformig]. The meshes are 

sometimes smaller even than the diameter of the minute lymphatics 
which form them, so that the net-work is very close, while at the same 
time the vessels are very irregular in size ; and this structure may to 
the superficial observer have the appearance of aggregated cells, which, 
however, are merely inequalities and slight dilatations of the vessels, 
forming a very close net-work. In other parts, where the meshes are 
larger, the reticulated structure is immediately evident.** The diameter 
of the vessels varies very much, but they are never so minute as the 
capillary blood-vessels ; and I am acquainted with no absorbent vessels 
which are not visible to the naked eye. Judging from Fohmann's repre- 
sentations, the lymphatics which he has discovered in branchiae must be 
the most minute that are known. It is not at all probable that any more 

minute lymphatics exist ; for the spaces which separate those that we are 
already acquainted with are very small. 

The second form in which the absorbents take their rise is that of 
small cells, more or less regular, and communicating one with another. 
Such appeared to me to be the structure of the injected lymphatics of 
the umbilical cord, and of those of the cornea, the nature of which, 

Erlangen, 1832, 

* Froriep's Not. N. 536. 565. t Das Weisse Blut. 

$ A farther account of the chyle is given in the section on Digestion. 

Das Saugadersystem der Wirbelthiere. i. Heft. Heidelberg, 1827, fol. 
|| Essai sur les Vaisseaux Lymphatiques. Strasb. 1824. Ann. des. Sc. Nat. 
% Osservazioni Antropo-zootomico-fisiologiche. Pavia, 1833. 
** See Plate i. figs. 7 and 8. 

• • • 

t. in 




however, is doubtful. This was also the appearance of the lacteals in 
the calf, which I injected by forcing the mercury into one of the trunks 
which were issuing from the intestines, filled with chyle, in a retrograde 
direction, so as to overcome the resistance offered by the valves. I suc- 
ceeded tolerably well in one case by forcible injection. The great num- 
ber of cells which are by this means filled with mercury suggests the 
idea that the absorbents take their rise in the cells of the cellular tissue 
itself. Fohmann,* indeed, is of opinion that what we call cellular tissue 
consists merely of lymphatic vessels. This, however, appears to me 
very doubtful. The identity between the cells that I have described 
and lymphatics is more especially problematical in those parts in which 
the cells are more particularly met with, and in which none of the long 
and regular lymphatic vessels occur, as is the case in the umbilical cord 
and cornea. From having compared good injections of lymphatics with 
other specimens in which the injection has not succeeded so well, and 
from some experiments of my own, I am inclined to believe that many 
of what are called the cellular lymphatic radicles are not really lympha- 
tics, and that the general form in which the radicle lymphatics exist even 
where these vessels are most numerous, is that of a close and often re- 
gular net- work. 

Although I cannot but greatly admire the beautiful injected speci- 
mens of the absorbents by the excellent Fohmann, which I have seen 
repeatedly in the museum at Heidelberg,— and 1 confess that these pre- 
parations excel everything of the kind that I have seen, — nevertheless, I 
can perceive a very distinct difference between the many perfect injec- 
tions and a few which are not so good, and doubt if everything that is 
shown by injection consists of lymphatic vessels. Thus, I cannot think 
that the appearances produced by injection of mercury under the cor- 
neal conjunctiva, and between the layers of the cornea, are owing to 
lymphatics. With regard to the lymphatics of the umbilical cord de- 
scribed by Fohmann,t I am quite in doubt. I injected the cord accord- 
ing to Fohmann's directions, and succeeded, even in a six months' foetus, 
in filling parts of the cord with mercury so well, that I could keep the 
preparation. Numerous small cells of T ^ T th to ^ th of an inch in dia- 
meter became filled with quicksilver. These cellules are certainly not 
formed artificially ; the majority of them are nearly equal in size, and 
the mercury passes from one cell to another without any extravasation. 
The greater part of the tissue of the cord around the blood-vessels is 
formed by them. It was only just at the umbilical insertion of the cord 
that the mercury filled several very short parallel canals. I know not 
whether these cells are lymph cells, and am certainly sceptical as to 

their being absorbing organs 


* Tiedemann, Zeitschrift fur physiologie, iv. 2 

The lacteals of the small 

t Loc. cit. 




intestines arise partly in the villosities ; but they also commence in the 
whole surface of the mucous membrane of the intestinal canal. When 
the lacteals are injected with mercury, none of the metal escapes from 
the surface of the mucous membrane. The villi also are not perforated 
at their extremity, as Lieberkiihn, Cruikshank, Hedwig, and Bleuland 
incorrectly supposed.* 

I have found that if a portion of fresh sheep's intestine, removed with 
the mesentery, and tied at one extremity, is strongly distended with 
milk by means of a syringe, the lacteals immediately become filled; 
and the milk moves very rapidly through them ; for if any of the lacteals 
are emptied by pressing onwards their contents, they are seen to re-fill 
immediately with milk from the intestine, particularly if the intestine is 
compressed at the same time. If the passage of the milk into the lac- 
teals in this experiment is effected without any previous laceration of the 
mucous surface, it would be an important fact. The injection of the 
lacteals with milk takes place most rapidly when the portion of intes- 
tine is pressed at its extremities, as if trying to diminish its length; the 
phenomenon is not so rapid when the compression is applied laterally. If; 
instead of milk, fine injection coloured with vermilion is used, the absorp- 
tion takes place very slowly ; and mercury cannot in this way be made 
to enter the lacteals at all. But with solutions of colouring matters which 
are perfectly soluble, such as indigo, the lacteals of the mesentery may 
by this method be very easily injected. In every case, however, in 
which the lacteals become injected by this procedure, there seems to be 
laceration of the mucous membrane at some point, for the lacteals fill 
suddenly ; and, on examining afterwards the inner surface of the intes- 
tine, there is frequently found a spot here and there, where the mucous 
membrane has lost its integrity. Consequently I attribute no importance 
to these experiments in reference to the question of the existence of 
openings in the extremity of the villi. I observed the phenomenon in 
no other animal than the sheep. 

It still, however, remains an undecided question whether the globules 
of the chyle enter the lacteals already formed. The varying opacity of 

the chyle, according to the difference of the food taken, is the chief 
argument in favour of their being taken up from the cavity of the intes- 
tine, and not afterwards formed in the lacteals. But where are the 
openings by which they enter these vessels?— for they must require larger 
pores than those by which all soft tissues, and even the walls of the ca- 
pillaries, are rendered permeable to water and matters in solution, but 
which are too minute to allow the escape of the red particles of the blood 
from the capillaries. All good observers agree that there are no visible 
openings in the villi of the intestines ; and I have myself repeatedly ex- 

* See Rudolphi, Anatomisch-physiol. Abhandlungen, and Albrecht Meckel, in 
Meckel's Archiv. t. v. 






amined the villi of the intestines of the calf, ox, rabbit, hog, and cat, 
without having even perceived any perforation in their extremity. No 
opening certainly exists at that part of the villi. 


The villi of the intestines are short 

processes, a quarter of a line to a line, or at most a line and two-thirds 
in length, rising from the surface of the mucous membrane, and giving 
this membrane, when magnified, the appearance of a thick fleece. Their 
form is sometimes cylindrical, sometimes lamellar, and frequently pyra- 

This is their character, however, as a general rule only in man., most 
mammalia, and many birds. Something similar is observed in a few 
fishes ; and in a serpent, the python bivitatus, Retzius has described 
processes of the mucous membrane of the intestine, which resemble 
villi, and can scarcely be considered as anything else ; although Ru- 
dolphi has said that fishes and reptiles have no true villi. A. Meckel 
is incorrect in characterising all villi as lamellae broad at the base and nar- 
rowed at their free extremity. It is true that they are flattened in most 
mammalia, as in the rabbit, dog, and hog; but in the calf, ox, and sheep, 
many of the villi are cylindrical ; and sometimes, as in the sheep and ox, 
the flattened villi are more numerous in one part of the intestines, in 
another the part cylindrical; and in the two last-named animals, particu- 
larly in the sheep, the villi in many parts of the intestines are flattened and 
broad, with cylindrical tips. By the villi becoming broader at their base, 
and being connected with each other so as to form folds, a gradual trans- 
ition is established from the villi of mammalia to the rugae or folds by 
which they are replaced in many birds and in reptiles. This transition 
is sometimes perceptible in the intestines of one and the same animal. 
Thus, in the rabbit, the pyramidal villi at the upper part of the small 
intestine are united at their base into folds, while in the middle portion 
of the same intestine they are more separate. The free extremity of 
the villi is sometimes rounded, sometimes rather pointed, and at other 
times, as in the dog, it is as it were truncated. 

Rudolphi at first believed that the villi were devoid of blood-vessels, 
and A. Meckel imagined that all the injection which entered them did so 
by imbibition or extravasation. Meckel could not have had before him 
good preparations of injected villi when he came to this conclusion. Not 
only can the vessels of the villi be beautifully shown by injection, as 
Doellinger, Seiler, and Lauth have described and represented, but I 
have, with the naked eye as well as with a lens, seen them filled with 
blood. Once I observed this in the calf, and afterwards in the dog, the 
intestine being examined immediately after death before it was washed. 

The extremity of the villi presents the same delicate texture as the 
rest of their surface. The assertion of Bleuland and others, that they had 
an opening at their extremity, was refuted by Rudolphi, who expressed 





all that lias hitherto been known of the structure of these parts in the 

following words : — " They have never any visible opening ; in their inte- 
rior there is a net-work of blood-vessels, which can seldom be demon- 
strated, however, except by injection; the net-works of lacteals also take 
their rise in the villi.^ 

It appears to me to be an important circumstance, that the villi are in 
part hollow, and are formed of an exceedingly delicate membrane in 
which blood-vessels ramify. The simple cavity I have found principally 
in the cylindrical villi. In examining, while it was quite fresh, the in- 
testine of a calf, the lacteals of which were white with chyle, I was sur- 
prised to find the villi filled with the same white opaque matter. On 
another occasion I found the villi of the small intestine of the same ani- 
mal not filled with white matter, but empty and distinctly hollow, which 
Rudolphi himself had once observed in a young pig. In the calf, and in 
the ox also, I was able, by means of a needle, to lay open the delicate 
cavities of the villi. The lamellar and rather broad intestinal villi of the 
rabbit also appeared to me to be hollow. A. Meckel once saw the 
appearance of a cavity in the villi, and has given a drawing of it ; but he 
supposed it to be produced by a folding of the membrane : which was 
certainly not the case in the villi which I have observed. By com- 
parison I have ascertained that the thickness of the membrane which 
forms the villi in the calf is y^^th of an inch, and the diameter of the 
capillary blood-vessels which run in this membrane may be reckoned at 

of an inch. I was able easily to convince myself of 
the existence of a cavity in the villi of the intestine in the calf, ox, sheep, 
and goat, and more easily in the narrow or really cylindrical villi, than 
in those which were flattened and broad ; but in the villi of the cat, hog, 
and dog, I did not see the cavity satisfactorily ; the villi in the dog 
seem to be hollow only in their upper part. The closely arranged plaits 
in the intestine of fishes, — the eel, carp, and clupea alosa, — have likewise 
no cavity ; they are solid folds. The flat broad villi, also, which are met 
with at certain parts of the intestine of the sheep, as well as the similar 
quite broad villi of the intestine of the rabbit, evidently do not contain one 
single cavity ; in all broad flat villi the lacteals seem to arise by more 
than one simple cavity. An opportunity occurred, at the dissecting- 
rooms in Berlin, of examining the villi of intestines in which the lacteals 
were filled with chyle in the human subject. They were found to contain 
a simple cavity running from base to apex. This was proved both by 
the microscopic examination of the villi by Henle, and by their injection 
with mercury by Schwann, who forced the mercury into the lacteals 
which were distinctly visible in the mucous coat, and thus filled the villi 
even to their closed extremity.* 


* There is something of a very different nature, which might be mistaken for hoi- 
low villi. This is a kind of epithelium, but of extreme delicacy. Rudolphi first men- 

from ^ T Vo 





In the experiment already mentioned, in which the lacteals are in- 
jected by distending the cavity of the intestine with milk,, villi filled with 
the milk may likewise be detected at some points. The experiment 
must be made very often before this accidental injection of the villi takes 
place. It is probable that the milk finds its way into the villi, not through 
the intestinal surface of the villi, but in a retrograde course from the net- 
work of lacteals which the milk had previously entered through lacera- 
tions of the mucous surface. When such villi, filled with milk, are exa- 
mined with the microscope, the narrow cylindrical villi appear to contain 
one single canal, while in the broad flat villi several irregular anastomos- 
ing canals are seen directed, for the most part, from the base to the free 
extremity of the villosity, there ending in a blind extremity, or con- 
tinued into the digitated processes with which the flat villi are termi- 
nated. The canals in the flat villi lie close together, forming a very 
irregular net-work; they exceed considerably the usual size of the capil- 

lary blood-vessels. 

[Professor Krause of Hanover* has lately had an opportunity of seeing 
the lacteals in the villi of the jejunum, beautifully filled with chyle, in the 
body of a young man who had been hung soon after taking a full meal 
of farinaceous food. The lacteal that issued from each villosity arose 
by several smaller branches,, of which some terminated by a free extre- 
mity, others anastomosed with each other.]f 

I have never perceived any opening at the extremity of the villi, 
and in my earlier examinations of them I could see no appearance of 
foramina on any part of their surface. But I have lately observed, 
in portions of the intestine of the sheep and ox, which had been 
exposed for some time to the action of water, that over the whole sur- 
face of the villi there were scattered very indistinct depressions, which 
might be regarded as oblique openings. However, I mention this obser- 
vation with great hesitation and distrust. The villi must be examined 
with a simple microscope, and must be under water on a black surface. 

of the 

The villosities of the in- 

testines, whether they have or have not open mouths on their surface, 
cannot possibly be the sole organs for the absorption of the chyle, for in 


tioned the epithelium as existing in the badger. In calves and kittens there is rfo diffi- 
culty in detecting a delicate unorganised membrane, which can be easily stripped off 
from the villi, like a glove. It is so very soft and friable, that if the intestine is much 
washed before it is examined, it will have separated of itself. In oxen it is still more 
delicate and is not easily seen ; when the intestine is washed, it separates from the 

embrane in the form of a mucous substance, in which the form of the villi is 
only here and there perceptible. It is very different from the solid epithelium of other 
mucous membranes. It is not solid, like an epidermis ; on the contrary, although co- 
herent in a membranous form, it is so nearly allied to mucus, that it seems to me to be 

mucous m 

a secretion m 

termediate between epithelium and mucus 

* MiiUer's Archiv. for 1837. Heft i. p. 5. 

f See plate i. fig, 9. 




many animals they do not exist. This consideration led me to examine 
the mucous membrane itself from which the villi are processes, and which 
is common to all animals. 

If in a well washed portion of the small intestine of any mammiferous 
animal we examine the structure of the membrane by which the villi are 
connected at their base, by means of a simple microscope, we perceive, 
without much difficulty, an extraordinary number of very small openings, 
which are about twice or three times as large as the red particles of the 
blood of the frog, and eight or ten times as large as the same bodies in 
mammalia. These minute openings are in mammalia sometimes so close 
and numerous, that the portion of membrane which separates them is 
scarcely as broad as the openings themselves ; generally, however, they 
are more widely separated ; and in this case they give a spongy and ex- 
ceedingly soft appearance to the membrane. The basis of the villi even 
appears in sheep and oxen, as it were beset with these foramina. They 
are the openings of Lieberkuhn's follicles.* 

The observations of Fohmann, in whose most perfect injections of the 
lacteals of the intestine of fishes the mercury never escaped on the in- 
ner surface of the intestine are opposed to the notion of the lacteals arising 

by open mouths so large as to be visible by the microscope, a notion 

which is disproved likewise by the fact of Schwann having, as above men- 
tioned, filled single villi of the human intestine with mercury injected 
from lacteals in the mucous membrane. 

The absorbent glands are in birds almost wholly wanting, except in the 
neck; and in reptiles and fishes they do not exist at all. In these ani- 
mals they seem to be replaced by mere plexuses of absorbent vessels. 
The glands themselves consist, in fact, merely of reticulated anasto- 
moses and interweavings of the vessels. The vasa inferentia of an ab- 
sorbent gland divide on entering it into small branches, and by the re- 
union of small branches are formed the vasa efferentia, which are less 
numerous, and somewhat larger than the vasa inferentia. In conse- 
quence of the free anastomosis of the two sets of vessels, — those entering 
and those leaving the gland, — so as to form a net-work of absorbents of 
which the gland is constituted, we are enabled to fill the lymphatics is- 
suing from the gland with mercury forced into those which enter it. 
The simpler absorbent glands resemble mere plexuses of absorbent ves- 
sels ; but one of the larger glands, when filled with mercury, has a cel- 
lular appearance. But even these apparent cells seem to be merely small 
dilatations of convoluted vessels; the net-work of absorbents in other 
parts has also frequently a cellular appearance; the small spaces be- 
tween the vessels not being distinguished without careful observation. 
The passage of mercury through the glands when the absorbent vessels 

* See Boehm, De Gland, Intestinal. Struct. Berol. 



going to them are injected is in favour of this opinion. The opposed 
opinions of Cruikshank, who admitted the existence of cells in these 
glands, and of Meckel, Hewson, and Mascagni, who regarded these ap- 
parent cells as dilatations of the convoluted absorbent vessels, can be 
easily reconciled. 

Abernethy found the mesenteric glands in the whale of a saclike (?) 
structure ; while, in the dolphin, according to Knox, they are solid.* 

Structure of the absorbent vessels. — It is very certain that the coats of 
the absorbents in the absorbent glands, as well as in other parts, are tra- 
versed by capillary vessels ; even the lacteals on the intestines, accord- 
ing to Fohmann's examination, possess an internal coat, which extends 
as far as the net-work from which they take their rise ; and it has been 
already mentioned that the capillary vessels in the villi are very nume- 
rous. Consequently, even the absorbents, which form the radicle part 
of the system, are to be regarded as organs of very complicated struc- 
ture, into which capillary vessels enter as elementary parts. The lym- 
phatics, with the exception of the net- work by which they commence, 
are formed of two coats, — an external smooth coat, and an internal one, 

which forms valves, by the arrangement of which the flow of the 

and its reflux in the opposite direction impeded. 

We have now to enquire whether absorbent vessels at their origin, or 
in any part of their course, have any communication with canals of other 
kinds besides that with the venous system, by means of the trunk of the 
absorbent system, — the thoracic duct. 

Do the absorbents communicate with secreting canals of glands ?— Cruik- 
shank, J. F. Meckel, the elder, and Panizza, have observed, in inject- 
ing the lactiferous ducts of the mammary gland, and the ductus he- 
paticus, with mercury, that the metal passed likewise into the lymphatics. 
Walter also filled the lymphatic vessels from the bile-ducts of the liver. 
It must not, however, hence be concluded, that the lymphatics at their 
origin have open communications with the secreting canals of the glands. 
Recently, in injecting the mammary glands of a bitch, I also found 
that the surrounding lymphatics became filled, but the cases in which 
this took place were those in which the vesicular extremities of the lac- 
tiferous ducts were not well filled with injection ; extravasation had, in 
fact, taken place, and, that being the case, the injection could find its 
way into no parts so readily as into the lymphatics, on account of their 
being so much larger than the capillary blood-vessels. If any open 
communication between the lymphatics and secreting canals really ex- 
ists, which Panizza denies, — and certainly with justice, — it could only 

towards the larger trunks of the lymphatic vessels is favoured, 

be between the lymphatics and the trunks of the secreting canals ; for 

* Froriep's Notiz. N. 158, 






the lymphatics which form the net-work by which the larger lymphatic 
vessels take their rise, are many times larger than the blind extremities 
of the secreting canals of the conglomerate glands. The connection of 

better proved. 


of the 

again rendered a subject of controversy, in consequence of Fohmann's 

Fohmann, Lauth, and Panizza, have discovered between the lympha- 
tics and the veins of the thigh and pelvis in birds, communications 
which are visible to the naked eye. I will presently describe the con- 
nection which I have discovered between the lymphatics of the thigh 
and the ischiadic vein in the frog. But this communication of the 
larger trunks is very different from a communication of single lymphatic 
vessels with minute veins, which Fohmann asserts to exist in birds, rep- 
tiles, and fishes, and of which he has given representations. Fohmann 
admits, that in man and mammalia, which have lymphatic glands, this 
communication of the absorbents with the veins does not exist, except 
in the glands. The statements of Lippi* concerning the communications 
of the lymphatics and veins, and his representations of them, have been 
shown by Fohmann-j- and Panizza to be undeserving of much confidence. 
Fohmann, however, maintains that the veins and absorbents do commu- 
nicate in the lymphatic glands, as had been observed by J. F. Meckel, 
the elder, and Ph. F. Meckel when injecting the absorbent vessels with 
mercury. When mercury is forced into the vasa inferentia of an ab- 
sorbent gland, the veins arising from the gland become filled, as Beclard 
also observed, very readily — often indeed much sooner than the efferent 
absorbent vessels. This led Fohmann into an error. On injecting in the 
seal the vasa inferentia of that mass of absorbent glands which in the dog 
and dolphin is called "pancreas Asellii," he observed, that when the glands 
were filled, the veins which arose from them, but no efferent absorbent 
vessels, became injected ; he thence concluded that this mass of glands 
has no other efferent vessels than the veins.J This error was corrected 

by Rosenthal,! who found that in the seal all the lacteals enter this 
mass of glands, and that one large efferent absorbent — the ductus Ro- 
senthalianus— issues from it. And in the dog and dolphin Rudolphi has 
seen a number of vasa efferentia issuing from this mass of glands. || Ro- 

* Illustrazioni fisiologiche e pathologiche del sistema linfatico-chilifero, etc. Fi- 

renze, 1825. 

t L. c. p. 4. 

% Fohmann, Anat. Untersuch. iiber die Verbindung der Saugadern mit den Venen. 
Heidelberg, 1821. 

§ Froriep's Not. ii. p. 6. Rosenthal's representations of the organs are to be found 
in Nov. Act. Nat. Cur. t. xv. p. 2. 

|| See Rudolphi's remarks on this subject in his Physiologie, 2 bd. 2 abth. pp. 241 







senthal's observations have been confirmed by Knox.* But, although 
Fohmann was wrong in supposing that in this case all the matter brought 
to the gland by the lacteals was conveyed away by the veins, still the 
fact remains, that mercury passes with extreme facility from the lym- 
phatics into the veins of the glands. Schroeder Van der Kolk ob- 
served the veins of absorbent glands, injected from the vasa inferential 
become filled without any of the mercury passing into the thoracic 
duct.f PanizzaJ injected a gland from two vasa inferentia, and observ- 
ed that the mercury passed from one wholly into the veins of the gland, 
and from the other into the efferent absorbent vessel. Gerber and Alb. 
Meckel§ also remarked the facility of communication from the absorb- 
ents to the veins. A. Meckel, however, as well as Rudolphi and E. 
H. Weber, doubt that this proves any real communication between the 
two sets of vessels. A. Meckel states, as a reason for his questioning the 
existence of a real communication, that, when the seminal duct of the 
epididymis of the dog is injected, the veins are also filled. I also doubt 
very much the existence of an actual open communication between the 
lymphatics and minute veins in the glands ; and the circumstances 
which induce me to doubt it are, that, when glands are injected from 
their excretory duct, the small veins of the gland also frequently become 
filled with the mercury, and that the cases in which this occurred to me 
were always those in which the ducts had not been well filled, — their acini 
not distended; and, lastly, that similar extravasation takes place from the 
ducts of the mammary gland into the lymphatics of the gland, and this 
likewise in cases where the acini of the mammary gland are not w r ell in- 
jected. The coagulated lymph in the absorbent glands resists the passage 
of the mercury ; the substance of the gland is lacerated ; and the coats 
of the lymphatics being supplied with capillaries which are continuous 
with veins, the rupture of one lymphatic in the interior of a gland must 
be attended with laceration of capillary vessels and veins. 

In the same manner, also, as E. H. Weber observes, fluids find their 
way very easily from the branches of the pulmonary artery into the 
bronchi, although no natural communication exists between them. I re- 
gard, in the same light, the passage of injection from one order of ves- 
sels into another, — from blood-vessels into the secreting canals, and from 
the secreting canals into blood-vessels,— in the secreting glands. || If, 
however, I should ever see a direct communication of a lymphatic ex- 
ternal to the glands with a small vein, I would acknowledge it as a thing 

* Edinb. Med. Surg. Journ. i. July 1824. Froriep's Not. 158. 

t Luchtmans, De absorptionis sanae et morbosae discrimine. Traject. ad Rhen. 1829. 

t Loc. cit. p. 56. 

§ Meckel's Archiv. 1828, p. 172. 

|| On the question of the communication of the lymphatics and veins, see E. H. 
Weber's observations in Hildebrandt's Anat. t. iii. pp. 113 — 121. 








evident to the sight, without, however, admitting the existence of such 

the right side. 

communication in the interior of a gland, where it is invisible. 

Terminations of the absorbents. — Since the communication of lym- 
phatics with small veins has not been observed in man and mamma- 
lia, the absorbent and venous systems can be regarded as connected 
only by the principal lymphatic trunk, the thoracic duct, which opens 
into the left subclavian vein, and by smaller lymphatic trunks which 
pour their contents into the internal jugular and subclavian veins of 

All other communications between the absorbents and 
the great veins seem to be exceptions merely to the normal structure ; 
such was the case witnessed by Professor Wutzer and myself, in which 
a branch was given off from the thoracic duct and immediately entered 
the vena azygos.* This branch is worthy of notice, however; for Pa- 
nizza has found that in the hog a regular communication exists between 
branches of the thoracic duct and the vena azygos.f 

Lymphatic hearts. — No motions having hitherto been observed in the 
lymphatic system, my discovery of small pulsating sacs connected with 
the lymphatic cavities in frogs is doubtless important. These organs 
must be regarded in some respects as hearts of the lymphatic system. I 
have found two pairs of them in the frog; one situated just under the 
skin in the ischiadic region, the other more deeply over the third cer- 
vical vertebra. The pulsations of these sacs are quite independent of 
those of the heart, and continue when the heart is removed from the 
animal, even after the body of the animal is cut in pieces ; the pul- 
sations of the cervical pair are not always synchronous with those of the 
pair in the ischiadic region, and even the corresponding sacs of opposite 
sides are not always synchronous in their action. They contract about 
sixty times in a minute. They contain colourless lymph ; and the lympha- 
tic vessels, and lymph spaces of the extremities, can be inflated from 
them. When air is forced into the inferior lymphatic heart, the lympha- 
tic trunks and the lymph spaces under the skin and between the muscles 
of the thigh become distended, as well as a superficial lymphatic running 
along the back. In a few instances a delicate vessel which accompanied the 
abdominal aorta also became inflated. When the air was forced into the 
superior or cervical lymphatic heart, the lymph spaces of the axilla 
became inflated. The inferior lymphatic heart on each side pumps the 
lymph into a branch of the ischiadic vein. By the superior, the lymph is 
forced into a branch of the jugular vein, which becomes turgid each time 
that the sac contracts. The vein passes forwards, receives a branch from 
the occiput ; the jugular vein then descends, receives a vein from the 
larynx, and at length opens into the vena cava superior. Similar pul- 
sating organs seem to exist in all reptiles. I have hitherto discovered the 

* See Wutzer in Miiller's Archiv. 1834. 
t Compare Otto, Patholog. Anat. p. 366. 





superior pair only in the frogs and toads. The inferior pair I have found 
in the salamanders and lizards; in these animals they are situated at the 
sides of the root of the tail behind the ilium, and are more difficult 
to find than in the frog, where they lie immediately under the skin.* 
Panizza has discovered the inferior pair of these lymphatic hearts also 
in serpents.f 



During the circulation of the blood through the minute capillary vessels, 
the red particles exert a vivifying influence on the parenchyma, and at 
the same time undergo a change of colour ; but they can be traced in their 
course into the veins, — they are not retained in the tissue. The fluid 
portion of the blood, however, with the fibrin and albumen in solution, 
like every fluid matter, is capable of permeating the walls of the capil- 
laries, and of being imbibed by the particles of the tissue contained in 
the meshes of the capillary net-work through which the blood is flowing. 
The dissolved ingredients of the blood thus imbibed by the parenchy- 
ma must serve the purposes of nutrition and secretion. Hence it is 

The fluid por- 
tion of the blood, therefore, will be imbibed by the tissues in considerable 
quantity, and what remains after the purpose of nutrition is fulfilled will 
collect in the net-work of lymphatics, which occupy in all parts of the 
body the interstices of the proper tissues of the organs ; a direct com- 

* Philos. Transact. 1833, p. 1. Poggend. Annal. 1832. Hft. viii. 

t [Professor E. H. Weber has given a very accurate description of the lymphatic 

Fig. 17. 

that venous blood contains less fibrin than arterial blood.t 

J m, 


hearts in a large species of serpent, the py- 
thon bivitatus. Each heart (fig. 17) is 
about nine lines in length and four lines 
in breadth, has an external cellular coat (fig. 
17> 4), and a thick muscular coat (fig. 17? 
5) ; four muscular columns running across 
its cavity, which communicates with three 
lymphatics (fig. 17, 1, — only one is here 
seen), and with two veins (fig. 17, 2, 2). 
All the orifices are provided with valves 
formed by duplicatures of the smooth mem- 
brane that lines the cavity (fig. 17, 5) of 
the heart. The heart lies in a kind oft ho- 
rax formed by the last rib, and by the transverse processes of the last lumbar and 
first sacral vertebra. The motions of the tail produce dilatation and contraction 
of this thorax, and Prof. Weber believes that these motions aid the heart in pumping 
the lymph into the vein (fig. 17, 3), which conveys the blood to the kidney. Each 
heart has, at its inner border, a small appendage or auricle (fig. 17, 7), the cavity of 
which is in no way separated from that of the rest of the organ.] 
X See page 114. 

T 2 






munication between the capillaries and lymphatics by means of vasa 
serosa is not needed for the passage of the fluid parts of the blood into 
the lymphatics, and indeed no such communication has been proved 
to exist. 

The fluid part of the blood having supplied the materials for the nu- 


trition of the tissues, is again returned to the circulation by the lympha- 
tic vessels. The lymph consequently must, in its composition, be exactly 
identical with the fluid portion of the blood or liquor sanguinis, and the 
blood itself must consist merely of lymph and red particles. An obser- 
vation which I have made, and which can be easily repeated, is sufficient 
to prove that the fluid contained in the lymphatic vessels is formed prin- 
cipally of the fluid parts of the blood, and is not a perfectly new fluid. I 


have observed that when the blood of the frog does not coagulate, the 
lymph also does not coagulate. Thus, when frogs have been kept out of 
water for eight or more days during the summer, their blood often loses its 
property of coagulation, and under such circumstances the lymph taken 
from the lymph cavities of the same animal affords no coagulum. Thus 
the peculiar state of the fibrin, or its absence in the blood of the frog at 
certain times, determines the very same state of the fibrin in the lymph, 
or its absence from that fluid. 


1. Of the absorption by the lymphatics and lacteals. 

It might at first appear doubtful whether the 
lymphatics and lacteals do really absorb, were it not that the lymph 
contains peculiar particles or globules, that absorption by the lacteals is 
a well ascertained fact, and that the colour of the chyle varies, becoming 
more white or more opaline according to the food taken. There are 
circumstances, however, which prove the fact of absorption by lymphatics 
in other parts. It is not merely that the lymphatics often become pain- 
ful, that red streaks appear in their course, and that the neighbouring 
lymphatic glands become swollen after the application, by friction, of 
irritating matters to the skin ; the lymphatics around collections of pe- 
culiar animal fluids have been seen filled with these fluids. I attribute 
no importance to the somewhat extravagant assertions of Masca 
states, that in animals which died from pulmonary or abdominal hemor- 
rhage, the lymphatics of the pleura and peritoneum have been seen filled 
with blood. But Assalini, Saunders, 

all observed bile in the lymphatics coming from the liver in cases°where 
the bile ducts were obstructed.* Tiedemann and Gmelin also, after 
tying the ductus choledochus in dogs, found the lymphatics of the liver 
filled with a fluid of a deep yellow colour ; the lymphatic glands which 
these lymphatics passed through were yellow, and the yellow fluid taken 









from the thoracic duct contained the components of the bile.* Lympha- 
tics around osseous tumours have been found to contain calcareous 

matter, t 

Absorption of pus.— Magendie,J who questions the absorbing power of 

the lymphatics, relates the following case observed by Dupuytren. A 
woman, who had a very large fluctuating tumour on the inner side of the 
thigh, died in the Hotel Dieu, A few days before her death, inflamma- 
tion had attacked the subcutaneous cellular membrane of the thigh. 

On dividing the skin over the tumour, Dupuytren saw some white points 
appear in the lips of the incision, and in the subcutaneous tissue white 
lines were visible, which were found to be lymphatics filled with pus. 
The inguinal glands were filled with the same matter, but no traces of 
it could be discovered in the lumbar glands or thoracic duct. Magendie 
also mentions another case which occurred at the Hotel Dieu : in con- 
sequence of compound fracture, a large abscess had formed, and here 
pus was found in the veins and lymphatics which arose from the part. 


On the other hand, Andral has examined, repeatedly, the lymphatics in 
the neighbourhood of abscesses, but never found any filled with pus. Pus 
contains globules, which are larger than the red particles of the blood ; 
in part twice as large, according to Weber; consequently the same question 


arises here as in reference to the absorption of the globules of the 
chyle. The entrance of the globules of pus into the lymphatics pre- 
supposes the existence of apertures of corresponding size in these vessels. 
In the parenchyma of organs where there is no free surface, no such 
apertures can exist. The fluid part of the pus may be easily absorbed 
into the lymphatics, but the presence of the globules of the pus in these 
vessels appears to me to be quite independent of absorption. I should 
regard them rather as the product of inflammation of the lymphatics 
themselves, or suppose that they have entered mechanically in conse- 
quence of solution of continuity of the lymphatics involved in the disease. 
Whenpus is found in the blood, — for instance, in the veins, — it is generally 
the product of inflammation in these veins themselves ; or it is pus which 
has found its way mechanically into the capillaries which have suffered 
solution of continuity in consequence of the suppuration. Thus, for exam- 
ple, after amputation, the pus of abscesses in the stump may find its way 
into the blood-vessels independently of absorption, or pus may be formed 
in the interior of the principal vessels divided in the amputation, in con- 
sequence of inflammation of these vessels. Pus being matter which has 
lost its healthy organic composition and properties, its presence in the 
veins gives rise to fresh deposition and inflammation ; thus are produced 
abscesses in other parts of the body, as is not unfrequently observed in 
consequence of great suppurations, and during the existence of suppurat- 

* Die Verdauung nach Versuclien, ii. 40. t Otto, Patholog. Anat. i. 372. 

Magendie's Physiologic, ii. 21. Milligan's translation, p. 522. 




ing wounds after amputation ; numerous abscesses in the lungs, liver, 
muscles, and other parts often occurring under such circumstances. It 
can scarcely be imagined that the pus in these abscesses had been ab- 

sorbed.* The presence of pus in the blood causes inflammation and ab- 
scesses in other parts, but is never followed by the secretion of pus with 
the natural secretions; for example, with the urine. It is, in my opinion, 
impossible for pus to be separated from the blood by secretion in the 
kidneys. The proximate principle of the pus may be separated in this 
way, but the globules of the pus cannot ; for no kind of globules can per- 
meate the walls of the capillary vessels. If it has ever occurred that, 
in consequence of suppuration in some other part, pus has been suddenly 
discharged with the urine from the kidneys, it could only have been by 
the pus having found its way into the blood, and thus excited inflamma- 
tion and abscesses in those organs. A sediment in the urine, not properly 
examined, is often mistaken for a metastatic secretion of pus from the 


Absorption of foreign substances. — Magendie first denied the absorbing 
power of the lymphatics. Hunter had asserted that coloured water 
injected into the abdomen of an animal is soon discoverable in the 
lymphatics. Flandrin has made the experiment in horses without 
success ; and Magendie assures us that with M. Dupuy tren he repeated 
similar experiments more than one hundred and fifty times, and never 
found any of the substances absorbed in the lymphatics. On the other 
hand, Mayer and Schroeder van der Kolk observed an evident, though 
slow, absorption of foreign matters from the intestinal canal by the 

The Academy of Philadelphia, as well as Lawrence and Coates, wit- 
nessed the absorption of prussiate of potash; but according to the 
observations of the Academy colouring matters were not absorbed. 
Halle and others, after the introduction of colouring matters, could not 
detect them in the thoracic duct, while they had evidently entered the 
blood and the circulation.f 

The result of most experiments is, that salts are the only foreign 
matters absorbed by the lymphatics. Thus the numerous experiments of 
Tiedemann and Gmelin, cited at page 240, show that colouring matters 
introduced into the intestinal canal are not taken up by the lacteals, 
although they are afterwards found in the blood and urine. Salts were 
the only foreign substances that they could detect in the chyle, and 
these but few times ; thus, only once out of many times, were they able 
to detect iron in the chyle of a horse to which sulphate of iron had been 
given, and prussiate of potash, and sulpho-cyanate of potash, each once in 


* See the excellent remarks of Cruveilhier in the article Inflammation of the Veins, 
in his Anatomie Pathologique. 

t See also Tiedemann and Gmelin, Versuche iiber die Wege> &c. 








the chyle of dogs. To these I may add an experiment of my own. I 
placed a frog with its posterior extremities in a solution of prussiate of 
potash which reached nearly as high as the anus, and kept it so for two 


I then washed the animal carefully, and, having wiped the legs 
dry, tested the lymph taken from under the skin with a persalt of iron, 
the lymph assumed immediately a bright blue colour, while the colour of 
the serum of the blood was scarcely perceptibly affected by the test. In 
a second experiment, in which the frog was kept only one hour in the so- 
lution, the salt could not be detected in the lymph. 


The conclusion 

which must be drawn from a consideration of all these facts, is, that 
the lymphatics do really absorb, but that their absorbing action is con- 
fined to particular fluids, for which perhaps they have an affinity : some 
foreign matters, such as salts, are taken up by the lymphatics, although 
with difficulty ; while others, such as colouring matters, are generally 
not absorbed at all. The matter which the lymphatics are ordinarily 
engaged in absorbing is the liquor sanguinis, which during the circula- 
tion of the blood through the capillaries is imbibed by the tissues. 
Besides this fluid, however, small molecules are taken up from the 
parenchyma of the organs and form the globules of the lymph, in the 
same manner as the globules of the chyle are, as it appears, absorbed by 
the lacteals with the fluid portion of the chyle from the food contained 

in the alimentary canal. 

The organic process by which the lymphatics absorb is, therefore, 
materially different from that by virtue of which the capillaries imbibe 
all foreign matters which are in a state of solution ; it is also different 
from the process of absorption in the radicle fibres of plants, by which 
every matter which is in solution is absorbed.* 

By simply comparing the chyle taken from the lymphatic system 
with the chyme in the alimentary canal, it will be at once seen, that 
the absorbents do not merely absorb, that they also produce a change 
in the matter which they take up. The new nutritive matter derived 
from the food does not acquire its property of coagulating spontaneously 

contained in the absorbent system of vessels, and this 
property becomes the more marked the further the chyle has advanced 
in these vessels. It is possible that the lymphatic vessels in other parts 
of the body have the same power of converting the albumen into coagu- 
lable matter. It is at any rate evident, that this action of the absorb- 
ents on the matters absorbed distinguishes completely the vital action 
exerted by them from imbibition, and from the process by which all 
matters in solution are received immediately into the capillaries. It 
is probable, as E. H. Weber has endeavoured to prove, that the absorb- 
ents produce a change in the composition even of foreign matters 

* Tiedemann's Physiol, i. 223. English Translation, p. 85. 

until it is 





which they take up. Thus Emmert has observed, that, after the abdo- 
minal aorta had been tied, the poison of the angustura virosa inserted 
into a wound of the foot, did not exert its deadly effect, and that prussic 
acid applied in the same way had also no effect on the animal, when the 
circulation in the lower extremities was stopped by ligature of the 
abdominal aorta. Now these poisons by mere imbibition could enter 
the lymphatics as well as the blood-vessels, so that the absence of their 
usual effects in these cases must be attributed to a change effected 
by the lymphatics in the matters which they absorb. 

by which the lymphatics and lacteals absorb I confess that the 

act of absorption in other parts, as well as in the intestines, is to me quite 
an enigma. Capillary attraction, by which some persons would explain 
so many processes in the animal body, accounts for the filling of capil- 
lary tubes only when they are empty, or when they have the power of 
emptying themselves from time to time ; it does not explain the absorp- 
tion and motion of the organic fluids. When, in the experiment before 
described, I witnessed the filling of the lacteals of the mesentery by milk, 
which was injected into the intestine so as to distend its coats, I fancied 
at the moment that I had discovered an explanation of the absorption of 
the chyle. But I gave up this idea at once when I recollected how slight 
the contractions observed in the intestines on opening the abdomen are, 
and that the small intestines generally appear collapsed. And I was still 
more induced to renounce this view on finding that generally, perhaps 
always, the injection of the lacteals in this experiment is attended with 
laceration of the internal coat of the intestines. Some kind of attraction 
must be exerted by the absorbents. As soon as the lacteals are filled 
beyond the point at which they pass through the muscular coat, the 
slightest contraction of the intestine by compressing the lacteals between 
the muscular fibres must tend to drive the" chyle onwards, and the ar- 
rangement of the valves of the lacteals necessitates its flow towards the 
receptaculum chyli. When the contraction of the intestine ceases, a 
vacuum is produced in the lacteals which have been emptied, and their 
refilling is the necessary consequence. But although this may take place 
in the intestines, it can never occur in parts which possess no contrac- 
tility; and in fishes the absorbents have no valves. It is probable, there- 
fore, that some other kind of attraction, and this certainly not of a mere 
physical nature like capillary attraction, but an organic attraction of a 
kind hitherto unknown, is here in action. I have never seen the slightest 
motion in the villi of the intestines, although I have laid open the intestine 
in a living rabbit and examined its internal surface under warm water. 
Nor have I observed any sign of movement even in the lacteals of the 
mesentery, in the receptaculum chyli, or in the thoracic duct. I have 
applied the wires of a strong galvanic battery to the thoracic duct of a 
goat, which was opened as quickly as possible, while still alive, but 





could perceive no contraction ; it was not till sometime had elapsed that 
the duct appeared to have become somewhat narrower at the point 
to which the wires had been applied, and presented several very incon- 
siderable constrictions. 


In no points perhaps do plants and animals so much resemble each 
other as in the ascent of fluids from absorbing surfaces in the absorbent 
vessels of animals, and the ascent of the sap in the vessels of plants. 
The ascent of the sap in plants is effected solely by the action of the 
roots and their spongiola.* The villi of the intestines are not essential 
organs for the absorption of the chyle ; for the absorption by the lym- 

* The absorption by the lymphatics in animals being involved in so much mystery, 
it appeared to me to be advisable to investigate the laws of the analogous process in 


It has been proved by Dutrochet, that the organs which effect the ascent of the 

sap in plants during the spring, are the terminal parts of the roots, — that the 
whole force by which the sap is impelled upwards is a vis a tergo exerted in the roots. 
Dutrochet cut off the end of the stem of a vine, which was about six feet high, and 
distinctly perceived that the cut surface of the stem continued to pour forth the sap 
uninterruptedly. The cause of the ascent of the sap, therefore, is not an attraction 
of the upper part of the plant for the sap in the lower part of the stem. Dutrochet 
then cut off the vine stem close to the ground, and observed that the effusion of 
sap from the upper extremity of the stem immediately ceased. The cause of its 
effusion, therefore, was not seated in the stem of the vine. The portion of the stem 
which still remained attached to the root, continued to pour out sap from its cut 
surface. Dutrochet now removed the earth from about the roots and divided them ; 
the cut surface of the remaining portion of the roots still continued to emit sap. 
Continuing the excision of the roots lower and lower, he always observed, that the 
portion remaining in the ground still emitted sap, even until he reached the terminal 
parts of the roots. The terminal portions of the roots, therefore, being the seat of 
the constant absorption of the sap, must, by taking up successively fresh portions, 
necessitate the ascent of that already absorbed. Dutrochet placed one of the radicles, 
which terminate with a whitish cone, in water ; and by the aid of a lens observed, 
that the cut surface became covered with water, which issued from the central part of 
the radicle. — (Dutrochet, F agent immediat du mouvement vital. Paris, 1826, 90.^ The 
absorption of matters by the mere extremities of the roots had been already demon- 
strated by De la Baisse and Hales. Hales immersed the extremity of the root of a tree 
in water, contained in a glass tube, and in six minutes observed a marked diminution 
in the quantity of the water* (Agardh, Algemeine Biologie der Pnanzen.) 

The terminal parts of the roots are what Decandolle calls spongiola. Agardh 
remarks, that the structure of these parts does not differ from that of the rest 
of the roots, except that the cells are small, and therefore more numerous ; but that 
the same cells which, when thus small and aggregated, have the power of absorp- 
tion, in a short time attain their full developement, and cease to absorb, leaving 
this function to be performed by new cells which are formed after them and below 
them. Agardh attributes the ascent of the sap to a polarising action of the roots and 
leaves by virtue of which the roots attract and the leaves exhale. This action he 
regards as something incapable of further explanation, like the polarising action of the 
magnet. This explanation cannot at any rate be applied to animals, for in them there 
is but one part of the act,— namely, the absorption by the radicles of the lymphatics, 
while, on the other hand, the lymph is poured into the blood. 




phatics is performed in other parts without villi, and in the intestines 
of many animals there are no villi. Nevertheless, the villi of the 
intestines are in some measure analogous to the spongiola of the roots 
of plants; it must, however, be remembered that the absorbents in the 
villi have the same structure as in other parts which have no villi. 

Dutrochet explained the phenomena of absorption both in plants and 
animals by the laws of endosmose. It is easy, however, to perceive 
that the phenomena of endosmose in dead animal membranes are by 
no means sufficient to account for the organic process of absorption in 
the animal and vegetable kingdoms. 

If the lacteals in the intestine and mesentery be supposed to be filled 
with animal fluids, and chyme to be in contact with the villi or net-work 
of lacteals, the fluid parts of the chyme would, according to the laws of 
endosmosis, enter the lacteals ; and the fluid, or dissolved parts of the 
matter already in the lacteals, would pass out and mix with the chyme ; 
if the chyme were more fluid than the chyle in the lacteals — if the mat- 
ters it held in solution were in a less concentrated state than in the 
chyle, — the chyme would enter the lacteals in larger proportion than the 
chyle would issue from them ; if, on the other hand, the matter dissolved 
in the chyme were in a more concentrated state, the chyle would per- 
meate the coats of the lacteals in an outward direction in larger quan- 
tity than the chyme would enter them. This, however, does not account 
for the wonderful process of absorption. If absorption is to be ex- 
plained in a manner analogous to the laws of endosmose, it must be 
supposed that a chemical affinity, resulting from the vital process itself 
is exerted between the chyme in the intestines and the chyle in the 
lacteals, by which the chyle is enabled to attract the chyme, without 
being itself attracted by it. But such an affinity or attraction would be 
of a vital nature, since it does not exist after death. To account for 
absorption, some might suppose that fluids are attracted by the external 
surface of the lymphatics, and repelled towards the cavity of the vessels 
by their internal surface; there are no facts either to confirm or to refute 
this hypothesis. 

It is probable that there is no mechanical apparatus for absorption 
in the radicles of the absorbent system, since in plants no such apparatus 
exists.* Absorption seems to depend on an attraction, the nature of 
which is at present unknown, but of which the very counterpart, as it 
were, takes place in secretion ; the fluids altered by the secreting action 
being repelled towards the free side only of the secreting membranes, 
and then pressed onwards by the successive portions of fluid secreted. 
In many organs, — for instance, in those invested with the mucous mem- 
branes, — absorption by the lymphatics and secretion by secreting organs 
are going on at the same time on the same surface. 

* See note at preceding page. 






Since the action of the absorbents depends on an organic property, 
circumstances which affect the organisation of a part will necessarily 
elevate or depress their action. Thus in inflammation, as Autenrieth 
remarked,* the action of the absorbents appears to be diminished, and 
hence the frequent occurrence of an enduring oedematous swelling around 

an inflamed part. 

It is still uncertain how the remedial means, which are supposed to 
excite absorption, produce their effects ; the cases, in which their action 
is evident, are few. There are substances called resolvents, which are 
capable of softening and dissolving the matters collected in superabun- 
dant quantity in the interstices of the elementary parts of tissues. The 
possibility of such a process taking place is shown apparently by the 
organic fluids themselves, in which one ingredient is frequently the men- 
struum for another; thus, for example, animal matters are kept in a 
state of complete solution by their organic union with mineral sub- 
stances, as is the case in the serum, or with other organic substances, 
as in the bile, in which picromel is the solvent menstruum of the chole- 
sterine. The use of resolvents in medicine is, however, very limited, 
because many substances, which out of the body have the power of dis- 
solving animal matter, have a destructive action on living animal textures. 
The assertion, that the lymphatics continue to absorb after death, ap- 
pears to me to be wholly without foundation.f 

2. Change effected by the lymphatic and lacteal vessels on their contents. 
The absorbent vessels, the parietes of which are supplied with capil- 
laries, seem to effect a change in the composition of the chyle and 
lymph. The absorbent glands have the same action ; they serve merely 
as means of increasing the surface of action ; for, in the lower vertebrata, 
they are replaced by mere plexuses, and are, in fact, merely plexuses in 
a more highly developed form. The chyle in the lacteals of the mesen- 
tery^ according to Tiedemann and Gmelin, is not coagulable until it has 
passed through the mesenteric glands. The lacteals and their glands 
appear, therefore, to have the power of converting, by the agency of 
their parietes, a part of the albumen of the chyle into fibrin. In many 
diseases this action of the lacteals on the elementary combination of 
their contents is modified, or the vessels themselves suffer from the action 
of fluids morbidly formed, as in scrofula. 

The absorbents are endowed with a peculiar sensibility to the action 
of foreign matters, becoming painful, sometimes inflamed and swollen, 
so as to be distinguished through the skin by red streaks when such 
matters have been absorbed. Under the same circumstances, the glands 
in the neighbourhood of the absorbing spot swell and become also pain- 
ful. Ordinarily, if the absorption of the irritating matter is not con- 

* Physiologie, ii. 224. 

•f See E. H. Weber, loc. cit. vol. iii. p. 101 






tinued, the swelling disappears, but sometimes the glands inflame and 
suppurate. This enlargement of the neighbouring glands is observed to 
take place under various circumstances, such as the introduction of an 
animal poison under the epidermis, the application of a blister, the bite 
of a snake, a cut or prick received in opening a putrescent 'body, or 
the inunction of tartar emetic ointment or mercury; it often occurs also 
in glands near an inflamed part in which matter is forming. Thus the 
inguinal glands swell in cases of gonorrhoea, or of venereal infection of 
the genitals when there is no gonorrhoea. The mesenteric glands seem 
to stand in the same relation to the intestines as the superficial glands 
to the skin ; they become inflamed when the intestines are inflamed and 
ulcerated, for example, in typhus abdominalis. 

3. The motion of the lymph and chyle. 
The powers by which the lymph and chyle are moved are unknown. It 
is possible that the absorbent vessels and thoracic duct propel their con- 
tents by imperceptible progressive contractions ; but it is not known 
whether this is the case. Tiedemann and Gmelin could produce no 
contractions of the thoracic duct by the application of mechanical and 
chemical irritants, which Schreger had previously asserted that he had 
succeeded in doing. I applied the galvanic apparatus to the thoracic 
duct in a goat, but without producing any contractions ; it was not till 
after some little time that some very slight constrictions of the duct 
were perceptible. Tiedemann and Gmelin, however, observed that the 
thoracic duct, when punctured, expels its contents in a jet. They sup- 
pose, therefore, that the lymphatics and lacteals, although not endued 
with rhythmic contractility, nevertheless have the power of propelling 
onwards their contents; an action which, if really exerted by them, must 
be facilitated by their valves ; the arrangement of which, indeed, is such 
that even external pressure applied to the lymphatics or lacteals by 
the muscles, must have the effect of propelling onwards the lymph and 
chyle. The suction exerted by the heart on the venous blood durino- 
the dilatation of its cavities, must also have a similar influence on th & 
motion of the chyle in the thoracic duct which communicates with th c 
left subclavian vein; and this action of the heart may alone have the effect 
of causing the chyle to follow the motion of the venous blood towards the 
heart, while, from the presence of a valve at the point where the thoracic 
duct opens into the vein, no venous blood can be forced back into th 
thoracic duct by the impulse arising from the heart's contraction. Th. 
sucking action of the heart, however, is not the primary cause of the 
motion of the chyle; for Autenrieth,* Tiedemann, and Carusf have ob- 
served that when a ligature is applied -to the thoracic duct, the part of 
the duct below the ligature becomes distended even to bursting. 


Physiologies ii. 115. 

f Meckel's Archiv. iv. 420, 




The motion of the lymph and chyle depends most probably, therefore, 
principally on the continued absorption going on in the radicle net-work 
of the lymphatics, in the same way as the ascent of the sap in plants, 
during the spring, depends solely on the constant absorbing action of the 

The lymphatic hearts which I have discovered in reptiles must con- 
siderably facilitate the motion of the lymph in these animals. These 
earts discharge the lymph of the lower part of the body directly into 

e ischiadic vein, that of the upper part of the body into a branch of 
the jugular vein. In mammalia and man it is only in the subclavian 
veins that the chyle and lymph are mixed with the blood, all the chyle 
and the greater part of the lymph being poured into the left subclavian 
vein by the thoracic duct. The lymph and chyle are often still detect- 
ible in the blood of the superior cava. The process of their conversion 
into blood in their course through the circulation has already been de- 
scribed at page 145. I have never been able to perceive the slightest 
motion in the thoracic duct and receptaculum chyli, or in any part of 
the absorbent system of mammalia ; and in reptiles the lymphatic hearts 
are the only parts of the absorbent system in which I have perceived 
any contractions. 

The rate of the motion of the lymph and chyle is quite unknown. It 
appears to be much slower than that of the blood, and is much less rapid 
than Cruikshank and Autenrieth supposed. Some idea of the rate at 
which the chyle moves may be formed by observing the time required 
for the distended lacteals in the mesentery of an animal just opened to 
become invisible, and by ascertaining the quantity of the fluid which can 
be collected from the thoracic duct. In Magendie's experiment half an 
ounce of chyle was collected, in five minutes, from the thoracic duct 
of a middle-sized dog. Collard de Martigny obtained nine grains of 
lymph, in ten minutes, from the thoracic duct of a rabbit which had 
taken no food for twenty-four hours. Collard de Martigny having pressed 
out the lymph from the principal lymphatic trunk of the neck in a dog, 
the vessel filled again in seven minutes ; in a second experiment it filled 
in eight minutes.* 

In the case already related, in which lymph escaped from a wound on 
the foot of a young man, the lymphatics on the dorsum of the foot and 
great toe became sufficiently filled in a quarter or half an hour to 
enable us to collect from them a considerable quantity of lymph in a 
watch-glass. In frogs the quantity of the lymph, and the volume of the 
cavities in which it is contained, are very great. If the capacity of each 
of their lymphatic hearts, of which the posterior are the larger, is esti- 
mated at one cubic line, the quantity of lymph which they would project 
into the veins in a minute, supposing that they emptied themselves 

* Journ. de Physiol, t. viii. 



entirely at each contraction, would be 4 x 60 = 240 cubic lines, since 
they contract about sixty times in a minute. But they expel only a part 
of their contents at each contraction. 

[Prof. E. H. Weber* has described a visible circulation of the lymph. 
It has been several times observed that the capillary blood-vessels, when 
viewed by the microscope, appear broader than the stream of blood in 
them. M. Poiseuille,t while watching the circulation in the capillaries, 
perceived that occasionally a globule of blood is thrown into the transparent 
space at the side of the current, and immediately loses its rapid motion ; 
that it becomes quite stationary for a time if wholly without the current, 
while if only partially immersed in the transparent space, it is rolled along, 
as it were, by the blood moving rapidly over it. M. Poiseuille inferred 
from these observations, that there is, in contact with the parietes of the 
vessels, a layer of liquor sanguinis which does not move ; and he states 
that M. Girard has demonstrated, that in the case of inert tubes of small 
diameter, the portion of a fluid moving through them which is in contact 
with their parietes is stationary. The appearances above described have 
been observed by Prof. Weber, and attributed by him, but less correctly, 
to the motion of lymph-globules in lymphatics surrounding the blood- 
vessels. The bodies which move thus slowly and irregularly along the 
sides of the current of blood are, for the most part at least, globular, as 
he states, but they appear to be larger than lymph-globules, and are 
certainly within the blood-vessels— they are evidently moved, as Poiseuille 
describes, by the same force that moves the current of blood, and are 
occasionally seen to re-enter this current.] 

* Miiller's Archiv. 1837. Heft ii. 

f Ann, des Scienc. Nat, Fevr, 1836, t. v. p. 111. 







Of the Chemical Changes produced in the Organic Fluids and Organised 

Textures under the influence of the Vital laws. 

The power by which elementary substances are, in the organic system, 
united into ternary and quaternary compounds, in opposition to their 
affinities, which would, under other circumstances, lead them to unite to 
form binary compounds, is without doubt a peculiar " force " or " im- 
ponderable matter" unknown in inorganic nature. This force or princi- 
ple is probably the same that governs the formation and nutrition of the 
different organs of the body after a plan of strict adaptation.* To attri- 
bute to electricity the production of all organic compounds would be a 
perfectly gratuitous hypothesis. Until the properties of the principle 
which influences organic combinations are known, it can be spoken of 
merely as something, the existence of which is certain, but of which the 
nature cannot be defined, — the vital principle or organising force. The 
law which regulates the action of parts endowed with this power on other 
substances is that of assimilation. 

The material changes which occur in the organic system may be di- 
vided into the purely chemical and the organic chemical. 

1. Purely chemical changes, regulated by the laws of elective affinity, 
ensue in the animal system when the vital principle loses its influence 
on the textures of the body, or becomes incapable of counterbalancing 
the power of chemical affinity. 

Concentrated acids and alkalies unite with the component elements of 
living animal bodies, and produce new substances, the animal matter 
being destroyed. Dilute muriatic and acetic acids in the gastric juice 
serve for the solution of alimentary substances. Berthollet supposes 
that the action of the caustic metallic oxides and salts depends on their 
yielding oxygen to the animal matter. When muriate of antimony is 
used, the inorganic substance is reduced, and the organic body oxidised. 
Bichloride of mercury is converted into the chloride by several organic 

* See pages 22—28. 





These purely chemical actions are of frequent application in therapeu- 
tics. The property which albumen possesses of precipitating corrosive 
sublimate, and uniting with it to form an insoluble substance, suggested 
to Orfila the happy idea of trying it as an antidote-* An antidote, as 
Huenefeld remarks, must have a strong affinity for the poison, and but 
slight chemical affinity for the animal body, so that it may be introduced 
into the system without ill effects. Sulphur neutralises arsenic, and, by 
giving rise to an insoluble compound, renders it less hurtful. It is on 
account of their insolubility that preparations of mercury which contain 
sulphur are inert in the treatment of syphilis.f The soluble sulphates are 
antidotes for poisoning by barytes and salts of lead, because the sulphates 
of barytes and of lead which are formed are insoluble.^ Magnesia 
neutralises the acid of the stomach. The success attending the admi- 
nistration of carbonates of alkalies in cases of lithic acid deposit, and of 

formation of calculus, from the urine, depends on the lithic acid being 
dissolved by the alkalies, and the urine rendered alkaline. Salts of ve- 


getable acids are useful in the same way, being converted into carbonates 


in the animal body or yielded in that form to the urine. Nitric acid, 

chlorine, and chlorates have been applied to sores of hospital gangrene 
and to cancerous sores, with success, in preventing the developement of 
sulphuretted hydrogen, ammonia, and hydrosulphate of ammonia from 
them. The use of mineral acids in putrid fever with a tendency to al- 
kalinity of the fluids may be regarded in the same light.§ 

The colouring matter of madder evinces a strong affinity for phosphate 
of lime even in the living body, the bones being the only parts which are 
coloured by it when it is taken with the food. Lastly, many foreign sub- 
stances taken up into the circulation, undergo change in part, and are 
again expelled from the system in their changed or unchanged state. 

2. In other cases certain substances, particularly those generated by 

the decomposition of the organic matter in diseased animals, act on other 
living animals in a manner which resembles the chemical process offer- 
mentation. Thus, contagions give rise to the production of similar 

changes of composition in the animal matters of other living beings. 

3. Chemical compounds and simple elementary substances may, how- 
ever, by affording the components which were deficient for the formation 
of new organic compounds in the body, favour the production of these 
compounds instead of decomposing them, and thus assist the operations 
of the vital principle. Thus the admixture of a certain proportion of 
mineral substances in the food is necessary. The change effected in 
the blood during respiration is an organic chemical change, in which a 
binary compound is formed and separated from the blood. 

4. Organic substances again may reciprocally decompose each other 

Huenefeld, Physiol. Chemie, i. pp. 65. 89. 

t Ibid. p. 66 




t Ibid. p. 67. 

§ Ibid. p. 72. 






even without the influence of the vital principle. Thus saliva, according to 
Leuchs,* converts boiled starch into sugar, and Tiedemann and Gmelin 
have shown that starch is changed in the stomach of animals into gum 
of starch and sugar. Fibrin or muscle are stated, like yeast, to excite 
fermentation in solution of sugar. Dr. J. Davy, however, on performing 
the experiment with beef, and continuing it three or four days, obtained 
no alcohol, but in its place gum.f Certain organic fluids,, such as saliva, 
gastric juice, bile, and pancreatic juice, serve to effect similar chemical 
changes in the animal economy. It is true that both the substances 
which act on each other in this way are quaternary compounds, and the 
products may still be quaternary compounds, without being reduced to 
binary combination. But organic substances once formed, even when 
subjected to the action of inorganic compounds out of the body, frequently 
undergo merely a change of organic combination. In the animal system, 
however, the action of organic fluids on one another is modified by the 
vital principle. The action of saliva and of bile in the process of digestion 
is not intelligible from the effects which they produce on organic com- 
pounds out of the body. ' 

5. The organic assimilation is, in the first place, evidenced in the 
changes of composition which organic fluids undergo while exposed to the 
influence of living surfaces endued with the vital principle. Thus, the com- 
position of the chyle absorbed from the alimentary canal undergoes a 
change in the lacteal system; the quantity of fibrin that it contains being 
greater in proportion to the number of mesenteric glands through which 
it has passed. In the formation of the different secretions the same 
action of the tissues on the fluids exists, but in a modified form, inasmuch 
as the components of the blood, which have been changed by the action 
of the tissues, are in this case separated from it. 


6. Lastly, assimilation is still more remarkably manifested in the con- 
version of the organic fluids into formative particles of the organs in the 
process of nutrition. The blood in the capillaries comes in contact with 
the smaller particles of nerves, muscles, mucous membrane, glands, &c. 
and each tissue exerts its assimilating action on the substances contained 
in the blood, changing their elementary composition, nourishing itself by 
their appropriation, and at the same time imparting to them the property 
of organising other matters in their turn. The essential phenomenon of 
this kind of assimilation is seen in the germinal disk (blastoderma) of the 
egg before vessels and the blood are formed. The germinal disk increases 
at the edges so as to form the germinal membrane at the expense of the 
yolk. The albumen of the yolk gradually undergoes a change of compo- 
sition, and at last ceases to be coagulable by heat. As soon as vessels 
are developed, growth is effected by the enlargement of the particles be- 
tween the capillaries, and by the formation of new vessels. If in an organ- 
ised texture, or living substance, A, B, C, and D are the elements 


Poggendorf's Annal. 183L 5. 

+ Kastner's Archiv. 1831. 396. 













which are combined in certain proportions to form each organic molecule, 
the organising principle of the part effects not only the combination of 
A, B, C, and D to form component particles, but also the union of these 
particles to form organic tissues ; and the organic fluids in contact with 
them are compelled, as it were, to change their composition to the com- 
bination of A, B, C, and D, that is, to form atoms of this composition, and 
to unite these atoms with the assimilating organ. By atoms here are 
intended not organic globules, but those invisible atoms which are sup- 
posed, in the chemical theory, to constitute the ultimate particles of a 


The production of vital phenomena — of muscular contraction, &c. — is 
constantly giving rise to the decomposition of a certain quantity of or- 
ganic material, to replace which new matter is supplied by the nutriment. 
In this respect, however inapt the comparison may be in other points, 
the animal machine resembles every other machine the action of which 
necessitates the destruction of some material, and which, like the steam- 
engine, requires a certain quantity of new matter for the continuance 
of its action. The most wonderful part of the process is, that, while the 
system gets rid of its old material and developes vitality in the new, it 
does not lose any vital power with the matter which it casts off; it would, 
therefore, almost appear, either that the vital principle leaves the decom- 
posed elements, and unites itself to the new matter, or that the nutriment 
itself is a source of increase of the vital principle, supposing that a portion 
of this principle becomes inert with the destruction of the old components 

of the animal body.* 

The first general law that regulates the formation of different animal 
substances seems, as Autenrieth remarks, to be the law of the attraction 
of similar parts for each other. But the particles of living structures 
have a great attraction among themselves, and therefore do not leave 
their combination to unite with the particles of the nutrient fluid ; they 
attract to themselves, however, the analogous particles from the blood ; 
so that in the exertion of this affinity it seems to be the blood which 
principally suffers a separation of its elements. I cannot conclude these 
remarks better than in the words of Autenrieth : — " Bone secretes only 
osseous matter; muscle secretes fibrin, and even a morbid scirrhus or a 
steatoma grows by the deposition of analogous matter. The growth, by the 
attraction of similar particles, is not manifested merely in the chemical 
components of an organ ; even in its organisation a similar law prevails. 

A polypous excrescence of the vagina or nostrils differs less in chemical 

composition than in its organisation from the surrounding healthy parts. 
Once formed, however, it continues to a certain extent to grow with its own 
peculiar structure. A cicatrix, although it possesses a structure different 
from the original organisation of the skin, continues to be nourished in 
the same form ; it even enlarges as the rest of the body grows/' t 


* See page 39 

f Autenrieth, Physiol, ii. p. 181 









Of Respiration 


Of Respiration in general. 

of the 

The essential respirable component of 

the atmosphere is the oxygen, which constitutes twenty-one parts in 100, 
seventy-nine parts being nitrogen. The proportion of carbonic acid in 
the atmosphere is extremely small; 10,000 volumes of atmospheric air 




the open country the maximum proportion of this gas was 5*74, the mi- 
nimum 3-15, in 10,000 parts. In the town of Geneva the air contained 
0*31 more carbonic acid than in the country.* There are also local im- 
purities, such as an organic matter, which rain water likewise contains, 
and which, with the concurrent action of light, reddens solution of silver.t 
Air, in which men or animals are breathing, loses a certain proportion of 
its oxygen, and in its place acquires nearly the same volume of carbonic 
acid. The same change is effected by respiration in pure oxygen. Al- 
though we do not regard respiration really as a species of combustion, 
yet the great similarity of the changes produced in the air by the two 
processes cannot but be remarked. In respiration, as in combustion, the 
nitrogen seems to act quite a neuter part, merely moderating the process 
by diluting the oxygen. 

Respirable and irrespirable gases. — In considering the various gases in 
reference to respiration and the respiratory organs, a distinction must be 
made between those that are merely incapable of supporting the process, 
and those that are actually poisonous in their action. Nitrogen and hy- 
drogen are instances of the former kind ; they do not support life when 
respired in their pure state, but when mixed with the necessary quantity 
of oxygen they are perfectly innoxious. Those gases, which from 
their affinity for animal matters are decidedly noxious to the system, 
must be again divided into two classes ; for several gases can be taken 
into the lungs although poisonous in their action, while others cannot be 
inspired in any considerable quantity, on account of their exciting spasm of 
the respiratory organs, particularly of the glottis. 

The gases may be classed according to their physiological effects as 

follows : 

* Berzelius, Jahrb. ubersetzt. v. Woehler, xi. 64. 
t Gmelin's Chemie, i. 442. 






I. Those which support the chemical process of respiration. 

a. Permanently without injury to life. — Atmospheric air. 

b. For a certain period, but not permanently. — Oxygen and nitrous 
oxide. The respiration of oxygen causes, it is said, even the blood in 
the veins to become of a bright red colour. But at length its effects are 
injurious. Allen and Pepys, however, experienced no ill effects from 
respiring pure oxygen ; and a pigeon which they placed in oxygen gas 
merely became restless and embarrassed, but recovered when restored 
to the air. Lavoisier and Seguin perceived no disturbance of the func- 
tions in Guinea pigs which were kept twenty-four hours in oxygen gas. 
Allen and Pepys found that when oxygen was inhaled, a larger propor- 
tion of carbonic acid was contained in the gas expired than under ordi- 
nary circumstances ; but in the case of a pigeon, less carbonic acid 
seemed to be formed than during respiration in atmospheric air. The 
respiration of pure oxygen is injurious to phthisical patients. Nitrous 
oxide gas supports life for a short time, but soon has a stupifying and 
intoxicating effect, producing excitement, illusions of the senses, con- 
fusion of mind, and, at length, syncope * A portion of the gas is absorbed 
into the blood, which becomes of a purple colour, while the face and 
lips have the colour of death. Nitrogen and a scarcely perceptible quan- 
tity of carbonic acid are expired with the gas from the lungs. 






ifluence, but fail 


Nitrogen and hydrogen. La- 

voisier and Seguin caused Guinea pigs to respire a mixture of equal 
proportions of oxygen and hydrogen ; no particular symptoms were pro- 
duced, and the experimenters found that the same quantity of oxygen 
was consumed as when the mixture consisted of equal quantities of 
oxygen and nitrogen, and that no hydrogen was absorbed. The re- 
searches of Allen and Pepys seem to show that when hydrogen alone is 
respired, nitrogen is exhaled from the blood. Allen and Pepys and Wet- 
terstedtt state that the respiration of hydrogen produces a tendency to 
sleep. I placed some frogs in impure hydrogen, as prepared from zinc 
and dilute sulphuric acid, and they became insensible in a few hours ; 
but when I had previously purified the hydrogen and freed it from the 
fcetid oil, by passing it through alcohol, a frog lived in it twelve hours, 
breathing from time to time ; at the end of twenty-two hours it was 
apparently dead, but still moved slightly when it was taken out and 

* Sir H. Davy, Researches on Nitrous Oxide. 

t Berzelius, Thierchemie., 101. Trait6 de Chemie, traduit par Esslinger, t. vii. p. 106. 







pinched. In subsequent experiments frogs lived only three or four hours 
even in pure hydrogen. 


'oisonous gases. — Carburetted hydrogen, phosphoretted hydrogen, 
sulphuretted hydrogen, arseniuretted hydrogen, carbonic oxide, cyano- 


Atmospheric air which contains x^o o^ °^ * ts v °l um e of sul 

phuretted hydrogen will, according to Thenard, destroy a bird ; when it 

contains g^th of its volume, it will destroy a dog ; and with -g^th, a 

horse. The above gases also destroy life when injected in small quan- 
tities into the blood * 


of the 


small quantities, excite coughing. — All acid gases, as well as carbonic acid 
gas, chlorine, nitric oxide, fluoboric acid gas, fluosilicic acid gas, and 
ammonia. Atmospheric air which contains more than 10 percent, car- 
bonic acid quickly produces asphyxia. Any fluid, water for instance, 
acts on the glottis like a solid body, exciting it to spasmodic contraction, 
so as even to produce suffocation ; but very little irritation is produced 
by the presence of fluid in the lungs themselves, and a considerable 
quantity of fluid is borne, when injected into them by an opening in 
the trachea. In the first case, death is produced by the closure of the 
glottis, which is unattended by ill consequences if there is an opening in 
the trachea. 

Aquatic respiration.— A part of the animals which inhabit the water 
the reptiles and aquatic mammalia, namely,— come to the surface 
to respire atmospheric air, and breathe by means of lungs; others, 
as the fishes, have gills, and respire the water itself, or rather the 
air which the water contains. The water of lakes, rivers, and the 
ocean, is impregnated with atmospheric air, or, more correctly, with 
oxygen and nitrogen, in determinate proportions, which it absorbs from 
the atmosphere. Humboldt and Provencal obtained from 10,000 parts 
of Seine water, by boiling, from 264 to 287 parts of gas, of which from 




to -3-UL 

™ 10 

was oxygen, and from 


to -jUg. carbonic acid. 

must not be imagined that the water itself undergoes any change during 
respiration, it is the gas with which it is impregnated that alone is 
changed, the oxygen being removed and the carbonic acid increased in 
quantity. When fishes are made to respire water impregnated with 
oxygen and hydrogen, the oxygen only is absorbed, the quantity of the 
hydrogen remains unchanged. If fishes are placed in water which has 
been subjected to long continued boiling, they die from want of oxygen 
in the space of four hours, during which time their respiratory move- 
ments are continued. Priestley found by experiment that fishes will live 
ten or fifteen minutes in water which had been freed from air and after- 
wards impregnated with nitric oxide, but that as soon as the smallest 

* Nysten. See page 142. 






quantity of atmospheric air gained access to such water, the fishes were 
seized with convulsive motions and died. 

The respiratory movements. — The chemical process of respiration is 
not essentially dependent on the respiratory movements. They merely 
serve to expel the air or water which have undergone the change in- 
duced by the chemical process that is constantly carried on between these 
media and the blood, and to renew the supply of fresh air or water. 

The lungs, by their internal surface, offer an immense expansion for 
the action of the blood and air on each other ; and, as they are never 
completely emptied by the act of expiration, this action is constant. 
By the contraction and dilatation of the chest, the motion of which the 
lungs follow, a portion of the altered contents of the pulmonary reser- 
voir is first expelled, and then a new supply introduced, to undergo 
change in its turn. The fishes take in the fresh water by the mouth, 
and then expel a portion, passing it through the branchise, the opercula 
or gill-covers being alternately opened and closed. 


Sir Humphrey Davy calculates that the 

human lung, after the strongest expiration, still contains thirty-five 
cubic inches of air, and after an ordinary expiration, 108 cubic inches; 


he regards from ten to thirteen cubic inches as the quantity usually ex- 
pelled at each expiration.* Herbstf found that adults of large stature, 
when breathing tranquilly, inspire and expire from twenty to twenty-five 
cubic inches ; persons of smaller stature sixteen or eighteen cubic inches. 

Necessity of respirat 

The length of time during which life can be 

supported without respiration being performed varies very much in diffe- 
rent animals, being shorter in the vertebrata, and more especially in the 
warm-blooded vertebrata than in other animals. Warm-blooded animals, 
placed in the vacuum of the air-pump, die in less than a minute ; birds, even 
in from thirty to forty seconds. Reptiles will live a considerable time in a 
vacuum, and in irrespirable gases ; and in Carradori'sJ experiments a tor- 
toise placed under oil lived from twenty-four to thirty-six hours. Frogs die 
in less than an hour, when placed under oil ; in water impregnated with 
air they live a long time, respiration being carried on by the skin. Ed- 
wards says that toads, which he confined in baskets and placed in the 
Seine, lived several days; and Spallanzani and Edwards § have found 
them live a few hours even in water deprived of its air. I have wholly 
removed the lungs of frogs, after tying them at their root, and the ani- 

* [The numbers quoted by the author, although mentioned by Sir H. Davy, in his 
different experiments, are not those which he considered most accurately to indicate the 
capacity of his lungs. Those which he gives are 254 cubic inches in a state of volun- 
tary inspiration ; 135 in a state of natural inspiration ; 118 after a natural expiration, 
and 41 after a forced expiration. This capacity Sir H. Davy considered below the me- 
dium, his chest being narrow.] 

f Meckel's Archiv. 1828. 
* Meckel's Archiv. v. 141. 

X Ann. de Chim. et d. Phys. v. p. 94. 
Influence of Phys. Agent, on Life, p. 31. 












mals still lived about thirty hours, respiration being performed most 
probably by means of the skin. In the experiment mentioned above, 
the frog placed in pure hydrogen showed distinct signs of life at the end 
of twelve hours, and respired from time to time, and after twenty-two 
hours was still only in a state of asphyxia. In experiments instituted by 
Humboldt and Provencal, gold fishes lived an hour and forty minutes in 
water deprived of its air by long boiling ; in water impregnated with 
carbonic acid, and in carbonic acid gas, on the contrary, fishes died in a 
few minutes ; while in nitrogen and hydrogen, in which fishes keep their 
gill-covers closed, they lived five hours. 

The lower animals differ very much in the degree in which respiration 
is necessary to them, but, generally speaking, it appears that respiration 
is not essential for the maintenance of their life. Carradori states 
that insects die immediately when immersed in oil, and according 
to Treviranus they may be killed very quickly by merely smearing the 
openings of the respiratory organs with oil. Biot, however, found insects 
of the families blaps and tembrio live eight days under the air-pump in 
air rarefied to a tension of from one to two millimeters. The larvae of the 
gad-fly, in Schroeder Van der Kolk's experiments, lived a considerable 
time in irrespirable gases. The larvae of some insects live in putrefying 
vegetable and animal substances, and seem to have little need of pure 
oxygen, although no insect is known which has not a system of tracheal 
tubes, and which, therefore, during life respires air. Berzelius saw lar- 
vae living in spring-water which contained carbonate of iron and some 
sulphuretted hydrogen. Leeches seem to live a long time without fresh 
water ; while Tiedemann found that holothuriae die in a single day if 
the sea-water in which they are kept is not renewed. Intestinal worms, 
which inhabit other living beings, seem to dispense with respiration.* 

* For an account of the respiration of hybernating animals refer to page 77 • The 
respiration of ova will be treated of in the third chapter of this section. The best works 
of reference on the subject of respiration in general, are — Groodwyn on the Connexion 
of Life with Respiration, London, 1788. Lavoisier and Seguin, Ann. d. Chim. 91, 
318. Menzie's Tentamen Physiol, de Respirat. Edinb. 1790. Crell, Ann. 1794, ii. 
33. Sir H. Davy, [Researches on Nitrous Oxide.] Gilbert's Ann. 19. 298. Pfaff, 
in Gehlen J. de Chem. v. 103. Provencal et Humboldt, Schweigger's Journ. i. 86. 
[Mem. d'Arcueil, t. ii.] Edwards, Ann. de Chim. et de Phys. 22. 35, [and Influence 
of Physical Agents, &c.] Dulong, Schweigger's J. 38. 505. Despretz, Ann. de Chim. et 
de Phys. 26. 337. Spallanzani, Mem. sur la Respiration, Geneve, 1803. Hausmann, 
de Anim. Exsang. Resp. Hannover, 1803. Sorg, de Resp. Insect, et Verm. Rudolstadt, 
1805. Nitzsch, de Resp. Anim. Viteb. 1808. Nasse, Meek. Arch. ii. 195. 435. Tre- 
viranus, Zeitschr. fur Physiol, iv. 1. 







Of the Respiratory Apparatus generally. 



certain changes in the air, or in the water impregnated with air, which 
comes in contact with it, is developed in a small space into a great extent 
of surface, so as to render the contact with this air or water more extend- 
ed, it constitutes a respiratory organ. 

Different forms of 

The developement of the 

respiring surface may take place either towards the interior of the body 




8, and 19,) in which nature seems to have exhausted all imaginable va- 
riations of form in the increase of surface towards the exterior. In the 
third form of respiratory organ, the increase of the surface for the contact 
of the air and the animal textures is obtained by the developement of 
a system of tracheal tubes, ramified to extreme fineness, and spread 
through the smallest portions of all organs of the body (fig, 22). This 
is the tracheal system of insects, and the tracheary arachnida. The 
lungs generally respire air ; there are, however, exceptions to this ; for 
instance, the respiratory organ of the holothuria consists of a tube rami- 
fied in an arborescent form, (fig. 18,) in which the respiratory function 
is performed by water being taken into the tubes, and again expelled 
from time to time. In animals provided with branchiae or gills, the respi- 
ration is generally effected by means of water, but sometimes by air, as 
is the case in the terrestrial Crustacea. 

Lungs and branchias, in their extreme forms, are completely distinct, 
but they often approach each other in their essential characters so nearly 
that it is difficult to determine to which type they belong. Thus, the gills 

of the cyclostomata, and of the sharks and rays, are inclosed in sac-like ca- 
vities, and the branchiae of the asidia form a branchial sac; but the cha- 
racters of the two kinds of organs are still more confounded together in the 
pulmonary arachnida, in which the respiratory organs have the charac- 
ters both of lungs and branchiae at the same time (fig. 21); and when 
Treviranus called them branchiae, and I named them lungs, we were 
perhaps both equally correct or incorrect. In some insects, too, there 
is a mixed form of respiratory organ, partly branchial partly tracheal. 

In the infusoria the only respiratory organs seem to be delicate cilia, 
with which, in many species, the surface is in part or wholly occupied • 
they are so minute that it requires the highest magnifying powers to 
see them. In the poly pif era the whole surface seems to serve the function 





of respiration. In some, as the alcy- 
onella, the tentacula seem to be at 
the same time branchiae. 

Among the echinoderrnata the re- 
spiratory organ of the holothuria is 
remarkable; it is a tube ramified in an 
arborescent form with terminal cel- 
lules,, (fig. 18,) respiration being per- 
formed by the contact of water taken 
in by the trunk with the inner sur- 
face of the organ. In the asterias 
family the respiratory organs are, 
according to Tiedemann, soft tubes 
upon the skin of the animal, into 
which the water has access.* 

In the cmnelida the respiratory or- 
gans are sometimes tufted branchiae of 
a branched form, (fig. 19,) as in the 
arenicola, and similar organs on the 
feet of the nereides. Sometimes respi- 
ratory sacs exist, which lie concealed 


under the skin, each having a sepa- 
rate external opening, as in the lum- 
brici, naides, and hirudines ; I have 
however, in one case observed that 
the peculiar respiratory sacs of the 
officinal leech contained a fluid se- 
cretion, — a small quantity of whitish 

Among the mollusca some breathe 
in the water by means of branchiae, 
others by lungs in the air. The first 
mode of respiration is that of the 


cephalopoda, (fig. 4,) some of the 
gasteropoda, and the conchifera (fig. 
3); the second is the mode of respi 
teropoda, as, for instance, the helicina 

Fig. 18.t 

Fig. 19.+ 


(fig. 20) 


branchiae are in the form of plicae, or laminae, which are united parallel 

* Tiedemann, Anatomie d. Rohrenholothurie, &c. 

t [The holothuria, after Tiedemann.— 1. The respiratory organ communicating with 
the cloaca (2); 3. the mouth; 4. tentacula; 5. contractile sac connected with the 
system of water tubes ; 6. organs of generation ; 7. the intestine.] 

X [The half of a single segment of the amphinoma, showing — 1. the tufted ramified 
branchia : 2. the dorsal oar ; 3. the ventral oar ; 4. membranous appendages of the fleshy 
tubercles, or feet,which support the bristles (5). Copied from the Cyclopaedia of Anatomy.] 






ramified, as in the doris, in which they surround the anus. In the con- 
chifera there are on each side, running the whole length of the animal, 
two leaf-like branchiae (i?.i7, fig. 3), each consisting of two layers, 
between which the ova find their way, to be there deve- Fig. 20.t 
loped.* In the ascidise the branchiae form a sac-like ves- 
tibule from which the alimentary canal commences, the 
inner membrane of the sac forming pectinated processes. 
The pulmonary gasteropoda are partly aquatic, as, for in- 
stance, the fresh-water snails, the limnaea, &c. and these 
come to the surface to take a supply of air ; others are 
terrestrial, as the limax and helix. The respiratory organ 


is a pulmonary sac, the external mouth of which opens 
and closes regularly (fig. 20). 

In the Crustacea the organs of respiration are branchiae, 
and this function is, in nearly the entire class, performed 
in the water. In the decapoda the branchiae are enclosed 
in a separate cavity at the side of the thorax, and consist 
of a number of branchial pyramids. In the brachyurous 
decapoda, each of the pyramids is formed of lamellae united to the axis of 
the pyramid in a pinnate form, but in the macrourous decapoda the lamellae 
are replaced by filaments. In the aquatic aselli the branchiae are simple 
lamellae ; in the terrestrial aselli, which respire air, they are simple hol- 
low leaf-like appendages. In several of the Crustacea the branchiae are more 
vesicular in form, as in the amphipoda. The branchiae of the Crustacea 
are attached either to the feet or to the abdominal surface of the body. 

The arachnida are divided into the pi g% 2 [.+ 

pulmonary and the tracheary arach- 
nida. The respiratory organs of the 
first order are situated at the under £ 
surface of the abdomen. They are 
small sacs opening externally, each 
by a separate stigma. The interior 
of the sac is divided in several com- 
partments by parallel partitions or A 
lamellae (fig. 21a); and when the sac 
is inflated from the external stigma, 
the compartments between the partitions become protruded externally, so 

* Von Baer, Meckel's Archiv. 1830. 

t [The Umax or common snail. — 1. The pulmonary sac ; 2. the opening by which 
the air enters ; 3. the veins which collect the blood from the body, and afterwards form 
a net-work over the pulmonary sac ; 4. the auricle of the heart, which receives the ae- 
rated blood by numerous orifices ; 5. the ventricle giving off two great systemic arteries.] 

% [Pulmonary sac of the scorpion, from the original figures of Professor Miiller, in 




that the surface of the sac presents the same series of divisions as exists 
in the interior (fig. 21, b). In most of the arachnida there is but one 
pair of sacs ; in others, as the mygales, two pair ; and in the scorpionidse 
there are four pair.* The aquatic arachnida respire the air which is 
confined among the hairs of their body when they descend into the water. 
The hydrachnida and pycnogonida 

would seem not to respire air at all. F%a * 22, + 

The tracheary arachnida, as the sol- 
puga, chelifer, phalangium, and aca- 
rides, resemble the insects in the 
structure of the tracheal tubes, which 
ramify through all parts of their body. 
Duges has also observed arachnida, 
the dysdera and segestria, — which 
have, at the same time, both pulmo- 
nary sacs and trachea. The poste- 
rior two of the four stigmata of these 


arachnida belong to the tracheae. 

All insects have a system of rami- 
fying tracheae, and in the greater 
number the respiration is aerial, the 
air being inhaled through a number 
of stigmata, which are generally situ- 
ated at the sides of the rings of the 
abdomen.f Through the stigmata 
the air is carried by the tracheae, in 
some insects, into vesicles from which 
the rest of the tracheal tubes arise ; 
in others, into longitudinal trunks, 
which ramify throughout the most 
delicate parts of the animal (fig. 22). 

Meckel's Archiv. 1828.— A. Portion of sac enlarged; 1. border of the stigma; 2. 
internal wall of the sac ; 3. external wall of the sac ; 4. one of the septa ; B. sac inflated ; 
1. margin of the stigma ; 2. undivided part of the sac ; 3. divided portion of the sac in- 

* I have described the pulmonary sacs of the arachnida more fully in Meckel's Ar- 
chiv. 1828, and in the Isis, 1828. 

+ See the representations of the tracheal system of many insects by Marcel de Serres, 

Isis, 1819, iv. 

T Principal tracheae of the mantis religiosa, seen from the abdominal surface, after 

Marcel de Serres, loc. cit. — 1. Communications of the tracheae with the stigmata ; 2. 
trachea* to the palpi, mandibles, &c. ; 3. nerves of the antenna* ; 4. trachea of the legs ; 
5. ditto of the thorax ; 6. ditto of the abdomen.] 

In several insects, particularly in the orthoptera, there are distinct respiratory 
movements— alternate dilatation and contraction of the abdomen. Beetles, before 





The larvae of many insects breathe by means of branchiae in the water ; 
and some insects, which in the larval state are aquatic, likewise respire 
water when they have attained their perfect condition, although they 
have an internal tracheal apparatus. In place of stigmata, these insects 
have branchiae at the commencement of the tracheae. These branchiae 
have the power of separating from the water the air which it contains, 
and which then passes into the ramified tracheae in the gaseous state. 
Branchiae are most frequent in the larvae of the neuroptera.* 

flying, seem to inflate themselves with air so as to unfold their wings, which, like other 
parts of the body, are supplied with air tubes. Treviranus has recently asserted that 
the stigmata of some insects are quite imperforate ; but Burmeister has already refuted 
this assertion.— (Burmeister, Entomologie, Berlin, 1832, p. 172 ; to which I refer for a 
description of the stigmata.) Some insects live in the water, but come to the surface 
to inhale air ; such is the case with the larvae of many dipterous insects,— the hydrocoris 
or water-bug, and some aquatic coleoptera. The dytiscus comes to the surface and in- 
hales air by the stigmata near the anus. The hydrophilus carries with it into the water 
bubbles of air entangled among the hairs of its body. Both these insects, while larvae, 
have their stigmata at the caudal extremity. The larvae of the common gnat— culex 
pipiens— has one trachea opening in the last abdominal ring, while the pupa has two pro- 
jecting out of the thorax. Other species allied to this gnat have branchiae, and respire 
water while in a state of larva. But the larva of the chironomus again has two tracheae 
at the caudal ring. In the stratiomys, the last abdominal ring ends in an air tube. The 
air tube of the larvae of the eristalis, which lives in the filth of sloughs, sewers, and 
privies, is very interesting. The last ring of the body is elongated into a membranous 
tube, within which there is a second horny tube ; and this, like the trachea of the gnat 
and stratiomys, is provided with a circle of bristles for the purpose of suspension on the 
surface of the water. The larva extends the tube to the surface of the water, the inner 
portion of the tube being protruded when necessary, so that the tube can thus be elon- 
gated to an extraordinary extent. The larva is, by this apparatus, enabled to live at 
the bottom of the fluid while it respires at the surface.— (See Burmeister, 1. c .) Some 
water-bugs also, the nepae and ranatrae, have tracheae. 

* The branchiae are, in some insects, hair-like filaments which contain in their interior 
the commencement of the tracheal tubes. The filaments are sometimes united in a 
radiated form, or they are branched. Such are the branchiae of the larvae and pupae of 
several gnats. The branchiae in several neuropterous insects are in the form of lamellae. 
The larvae of the gyrinus respire by means of hair-like branchiae at the sides of the rings 
of the body. Branchiae are most frequent in the larva of the neuroptera. The ephe- 
mera has, at the sides of the body, fin-like branchial lamellae, in the interior of which 
the air tubes take their rise. The branchiae of the larva of the dragon-fly are situated 
in the last ring of the body. In the agrion they consist of three great fringed lamellae. 
The tuft-like branchiae of the larvae of the libellulae are situated in the rectum, so that 
the tufted ends of the stems of the air tubes penetrating the membrane of the intestine 
project into its cavity. The larvae of the phryganeae and semblis have filamentous or 
leaf-like processes at the sides of the abdomen. Among the dipt era the larvae of the 
chironomus have tracheae and an aerial respiration ; but the pupae have branchial tufts 
on the thorax, and breathe by means of water. The anopheles, while in the larval state 
has branchiae at the caudal extremity ; when a pupa it has tracheae. Among the le- 
pidoptera, the caterpillar of one moth, the botys stratiotalis, is aquatic. When the 
larvae and pupae, which breathe by means of branchiae, undergo transformation thev lose 









Respiratory organs of fishes. — In the osseous fishes there are four gills 
on each side, supported by the same number of branchial arches.* 
Each gill consists of a double series of lancet-shaped lamellae attached 
to the branchial arch, like the teeth of a comb to its back. These lamellae 
are frequently united for some distance at their base; they give off at right 
angles smaller lateral lamellae. Each of the four branchial arteries, (see 
fig. 5) commencing its course at the inferior extremity of the branchial 
arch, runs in a groove along the convex border of the arch to its upper ex- 
tremity, gradually diminishing in size ; the veins run parallel with, but 

the branchiae and acquire stigmata, through which they inhale air. Representations of 
the branchiae of aquatic insects, by Suckow, will be found in Heusinger's Zeitschrift 
fur Organ. Physik, bd. ii. ; and a more extended description of the respiratory organs of 
insects generally in Burmeister's excellent Entomologie. 

* The structure of the gills of fishes has been thoroughly investigated by Rathke. 
(Untersuchungen iiber den Kiemenapparat und das Zungenbein der Wirbelthiere. 
Riga und Dorpat, 1832.) The following account is partly extracted from his work: 
[A great portion of the description of the respiratory apparatus of fishes and amphibia, 
having reference rather to comparative anatomy than physiology, has been omitted by 
the translator from the text and placed in the form of notes.] 

1. Skeleton of the branchial apparatus . —The lower jaw of the osseous fishes is sus- 
pended to the os quadratum, which here consists of several pieces, with which three 
other bones belonging to the operculum are connected posteriorly. 

Behind the lower jaw are the two hyoid arches, which consist each of several pieces, 
are connected by their external extremities to the os quadratum, and are united below 
in the middle line behind the root of the tongue ; they have frequently a copula, or 
intermediate bone, between them, and under them the azygos portion of the hyoid bone. 
To the arches of the hyoid bone are attached the osseous branchiostegous rays, which 
support the opercular membrane. Behind the hyoid arches are situated, in the osseous 
fishes, four osseous arches, — the branchial arches, — to which the branchial lamellae are 
attached like the teeth of a comb to its shaft. The highly vascular tissue of these 
lamellae is supported by cartilaginous spines, which may be compared to the radii 
branchiostigi which arise from the hyoid arches, which have no branchiae. The 
branchial arches consist of several, generally four portions; in the posterior arch 
there are not so many. In many osseous fishes there are, on the inner surface of the 
branchial arches, several small bony plates beset with small teeth. If the superior 
portion of the branchial arch on each side has many of these teeth, it is called the 
os pharyngeum superius. Between the arches of the one side and those of the other, 
where they meet each other, there are two or four bony or cartilaginous pieces, form- 
ing copula?. Behind the last pair of branchial arches are the inferior pharyngeal 
bones, consisting of one piece on each side. They may be compared to a branchial 
arch without branchiae. The branchial arches and pharyngeal bones are situated, in 
most fishes, under the cranium ; in others, partly under the first vertebra. In the 
sharks and rays, the cartilaginous ossa quadrata support the lower jaw and the hyoid 
arches. Both the os quadratum and the hyoid arch have cartilaginous rays connected 
with them : those which are attached to the ossa quadrata correspond to the opercular 
bones • while those attached to the hyoid arch are analogous to the branchiostegous rays 
of the osseous fishes. The four cartilaginous branchial arches of the sharks and rays are 
situated under the commencement of the vertebral column, and consist of four seg- 
ments. A cartilaginous plate, situated behind the branchial arches, corresponds to the 




in the opposite direction to, the arteries, becoming larger as the latter 
become smaller, and, meeting on the vertebral column, unite to form the 
aorta. Each branchial artery gives off in the course just described as 
many branches as there are branchial lamellae. These branches bifurcate 
twice, and terminate in the lateral capillary vessels of the smaller lamellae, 
in which the veins take their rise and run in a corresponding manner on 
the opposite side of the branchial lamellae,* 


inferior pharyngeal bones of the osseous fishes. The branchial arches here, as in the 
osseous fishes, bear cartilaginous rays, directed outwards and backwards. 

In the larvae of the salamanders and frogs, and in the proteus family, the cartilagi- 
nous apparatus for the support of the branchia is, to a certain extent, formed of the 
same parts as in the fish. The os quadratum supports the inferior jaw, and generally 
the anterior cornu of the os hyoides also. The branchial arches do not consist of several 
segments, as in the fish ; they are four in number, except in the proteus, in which 
there are but three ; they are attached to the single or double posterior cornua of the 
os hyoides, which Rathke, however, regards as segments of the branchial arches. 

During the transformation of the amphibia from the larva state, the cornua of the 
os hyoides of the frogs and salamanders do not disappear, but they undergo a change of 
form. Of the branchial arches there remains merely a rudiment of the first arch 
which in the salamander becomes connected with the two cornua of the os hyoides. 
(Siebold, Observ. de Salamand. et Tritonibus.) In the caeciliae the os hyoides has four 
pairs of arches throughout life. (See Rusconi, Delia Circolazione delle Larve delle 
Salamandre.) It is remarkable that the cornua of the os hyoides in the lizards, even in 
the full-grown state, still present two, or even three pairs of arches. Rathke has made 
a corresponding series of observations on the embryos of mammalia, from which it re- 
sults that in them the delicate branchial arches, as as already related at page 166, are 
at last reduced to the os hyoides ; the hyoid arch becoming the anterior, the first 
branchial arch the second cornu of the os hyoides. It appears, however, that the 
branchial arches do not at all contribute to the development of the larynx, which is 
formed independently. 

2. Branchial opercula. — In the osseous fishes the branchiae are covered in by the oper- 
cular bones, which are connected with the os quadratum. In the sharks and rays, 
besides the cartilaginous radii which supply the place of the opercular bones, there are 
cartilaginous bands lying under the skin, parallel with the branchial arches, and form- 
ing an upper and an under series, so that the opercular bones of the osseous fishes 
are here, as it were, multiplied. These external opercular cartilages constitute, in the 
petromyzon, a very complicated external branchial skeleton ; while the branchial arches 
themselves are wanting in these animals. 

In the larvae of the salamander, and in the proteus and axolotl, there is a lamina of 
the nature of a branchial operculum, but it contains no osseous or cartilaginous plates 
in its interior ; the operculum of the larvae of the frog is also merely membranous. 
This shows, as Rathke has pointed out, that the opercular bones attached to the os 
quadratum in fishes correspond to no bone in the higher vertebrata, and are, in fact, a 
structure peculiar to fishes. Least of all can they be compared to the auricular bones 
of higher animals. Huschke supposed that the auricular or ear bones were formed 
from portions of the branchial arches. But this is disproved by the fact which Windisch- 
mann observed, that in the axolotl there exist, simultaneously, branchial arches and 
two auditory bones, which are not contained in a tympanic cavity. 

* Cuvier, Hist. Nat. des Poissons, tab. viii. 






In the osseous fishes, and in the sturgeon, the branchiae are unattached 
externally, being covered in merely by the moveable operculum, or, as 
in the eel, they are closed in by the branchial membrane, so as to leave 
a single opening only for the passage of the water. 

In the sharks and rays there are four branchial arches, as in the osseous 
fishes ; but from each arch a membrane extends to the skin, forming a 
septum between the different branchial cavities, of which there are five ; 
these cavities are covered in externally by the skin, through which there 
is a separate opening into each. The branchial lamellae arise from the 
arches, in the form of parallel folds of the mucous membrane lining the 
cavities. The first four cavities have each a single gill, or series of 
branchial folds, both on their anterior and posterior wall ; the last cavity 
has but one branchia, namely, on its anterior wall. The gill on the an- 
terior wall of the first branchial cavity is attached to the arch in front of 
the branchial arches ; the succeeding single gills are situated on the 
surface of the membrane, separating the branchial cavities, and are con- 
nected, therefore, two with each branchial arch. The branchial cavities 
communicate internally with the pharynx.* 

The respiratory organs of the tadpole are 

Branchia of 

branchiae. There is a branchial cavity on each side, and each cavity 
contains four branchial arches, from which branchial lamella? arise. The 
branchial cavity on the right side is completely closed in by the skin ; 
on the left side a small opening is left. The anterior extremities are 
developed in the branchial cavities. 

* In the cyclostomata likewise there are branchial sacs with external openings, the 
sacs being formed by the union of two branchiae. There are no branchial arches' and 
in their place there are merely membranous septa, which are invested with mucous 
membrane on both sides, at their posterior part. The branchial lamellae are formed 
of thick folds of this mucous memaerane. In the ammrraetes there are six, in the 
petromyzon there are seven of these branchial sacs and foramina. In the ammocoetes 
the internal branchial foramina open into the pharynx, in the same manner as the 
branchial clefts of the osseous fishes. In the petromyzon, however, the seven internal 
brancheal foraminae opens into a branchus which lies in front of the oesophagus, and is 
closed posteriorly, but in front communicates with the mouth. 

Ehrenberg has discovered in the sudis ^Egyptiaca a spiral organ, connected with 
branchiae, and of which the use is quite an enigma. In some fishes there are accessory 
branch^, as in the heterobranchus anguillaris, in which they are arborescent in form. 
In the anabus and some other fishes which pass some time out of the water, they are 
wrinkled or plicated. In the foetal state the sharks and rays have also filamentous 
external branchiae, and it is remarkable that these organs project from the spout-hole in 
front of the os quadratum, which shows some analogy between this opening and the 
other true branchial foramina. On the branchial appendages, see Rathke, loc. cit. • 
the arborescent branchial appendages of the heterobranchus anguillaris are described 
in Burdach's Physiology, bd. iv. p. 161. 

f On the structure of the respiratory organs of the larvae of the caduci-branchiate 
amphibia, and of the proteidea, consult Cuvier, Oss. Fossil, t. v. 2. Humboldt and 
Bonpland, Beobacht. aus der ZooL Tubing. 1806. Rusconi, Configliachi del proteo 








The larva of the salamander has external gills, with four branchial 
clefts. The proteus family have also external branchiae, three in number, 

attached to branchial arches. 

(fig. 8), there are three 

branchial clefts on each side, in the proteus two, and in the axolotl four. 
The proteus family, throughout life, as well as the larva of the salaman- 
der and frog, in the second stage of their development, have both lungs 
and branchiae, and consequently respire both air and water. The distri- 
bution of the branchial vessels of these animals is described at page 164. 
The lungs of reptiles and amphibia are essentially mere sacs, of which 
the internal membrane is developed into folds, forming cells, so as greatly 

Fig. 23 * 




to increase the extent of surface (fig. 23). In most amphibia there is 
a membranous trachea leading to the lungs, but it is generally very short ; 
in the anourous amphibia the larynx leads almost immediately into the 
membranous bronchi. The first appearance of cartilaginous plates in the 
bronchi is in the dactylethra, in which they form very irregularly 
branched and even perforated lamellae, having no resemblance to bron- 
chial rings. In the pipa, which is allied to the dactylethra, cartilaginous 
rings are met with. The bronchus of the caeciliae has regular rings of 


In the true reptiles the respiratory surface is extended by increase of 
the number of cells in the interior of the lungs. (Fig. 23, c.) 

In birds the lungs do not occupy the greater part of the thoracic 
cavity, as in mammalia. They lie at the posterior part, intimately con- 
nected with the ribs and bound down by the serous membrane, which 
lines the common cavity of the abdomen and thorax ; for in birds the 
diaphragm is not developed. On the surface of the lungs there are 
openings, through which air passes from the bronchi into large cells, 
situated around the pericardium and between the viscera of the abdo- 

anguino. Pavia, 1819. J. Midler's Beitrage zur Naturgeschichte und Anatomie der 
Amphibien. Tiedemann's Zeitschrift, iv. 2 ; and also page 163 of this work. 

* [Diagram, showing the gradual development of the cellular lungs of reptiles. 
A. the upper portion of the lung of a serpent. The summit of the lung has cellular 
parietes ; the lower part is a mere membranous sac. B. the lung of a frog, in which 
the cellular structure has extended over the whole internal surface of the lung, but is 
most considerable at the upper part. C, lung of the turtle, — the cells have extended so 
as to fill the interior of the lung.] 








The bird can distend these cells with air, but cannot by that 
means render itself lighter for the purpose of flying.* The cells com- 
municate again with the cavities of the bones, the majority of which are 
filled with air. The body of the bird is thus of course rendered speci- 
fically lighter than if its bones contained medulla. When a bird de- 
scends from a great elevation, where the air is rarefied, into a denser 
atmosphere, the air within its body very soon acquires the same tension 
as the surrounding air. Another peculiarity in the structure of the 
ungs in birds is, that their bronchi terminate in short blind cylindrical 
tubes, which lie side by side and have cellular parietes. In the embryo 
of the bird these tubes are still more distinct and more separated from 
each other, and have terminal dilatations. Retziusf remarks, likewise, 
that the bronchial tubes in birds communicate with each other. 

In man and mammalia the structure of the lungs is essentially differ- 
ent. The minute bronchi have not the cellular 
parietes which we have described in birds, but 
terminate each in a distinct cell (fig. 24). These 
cells, or air vesicles, do not communicate one 
with another, their only opening is that of the 
minute bronchial twig which leads into each. 
Reisseisen§ has described a small artery, with 
its accompanying vein, going to each of these 
cells and forming around it a capillary net-work, 
which is so close that the diameter of the meshes 

is scarcely so great as that of the small vessels which form it. The dia- 
meter of a pulmonary vesicle is twenty times greater than that of one 
of the capillaries which are distributed in its parietes. The diameter of 
the pulmonary artery being ^th smaller than that of the aorta, — their 
diameter being in the proportion of five to six, — the area of the pulmo- 
nary artery, in comparison with that of the aorta, must be in the pro- 

Ftg. 24.$ 

, Mm v 

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portion of twenty-five to thirty-six, or of about two to three. 


therefore, the smallest divisions of the pulmonary artery bear the same 
proportion to the trunk, as the capillary vessels of the body bear to the 
aorta, the united area of the capillary vessels of the lungs ought to oc- 
cupy two-thirds of the space which the area of the capillaries of the rest 
of the body would comprise. It is very improbable, however, that this 
is the case ; consequently the increase of capacity with which the rami- 
fication of the arteries of the body is attended must be much greater