HX64098516
QP40.H211898 Essentials of physio

RECAP

mmM

Essentials of
Physiology

H.A.HareM.D.

Th

The U!
-vill be a
loss to di
when he
be put in

ANEWV

ESSENTIAL

Surgeon in Ch
phia, etc. Pri

This lat
sents the mc
nevertheless
pages with a

Columbia {Bmbersttp
m tfje Cttp of J^eto gorfe x ^ ^

COLLEGE OF PHYSICIA
AND SURGEONS

NS »

Reference Library

Given

Essentials of Ph;

Revised and

(Price, 81.00 n
Essentials of Sun

on Antiseptic

ward Marti:
Essentials of Ana

180 illustrate

M.D.
Essentials of Me<

organic. By
Essentials of Obs

larged. 75 illi

ton, M. D.
Essentials of Pathology and Morbid Anatomy. 6th

thousand. 46 illustrations. By C. E. Armand

Semple, M. D.
Essentials of Materia Medica. Therapeutics and

Prescription-Writing. 4th edition. By Henry

Morris, M. D.
Essentials of Practice of Medicine. By Henry

Morrb, M. D. An Appendix on Urine Exami-
nation. Illustrated. By Lawrence Wolff,

M. D. 3d edition, enlarged by some 300 Essential

Formulae, selected from eminent authorities, by

Wm. M. Powell, M. D. (Double number, price,

82.00.)
Essentials of Diseases of the Skin. 3d edition. 71

letter-press cuts and 15 half-tone illustrations.

By Henry W. Stelwagon, M. D. ($1.00 net.)

by

-^.V

/ERS.

md answers,
, often is at a
ually puzzled
estions could

ND SERIES.

LEASON, S. B., M. D,

ispensary of Philadel-

iccurately repre-
11 in compass, it
upward of 200
original sources.

IES.

th edition. With 6211-
;. Cragin.M.D.
Bandaging, and Vene-
rations. By Edward

s Toxicology, and Hy-
By C. E. Armand Sem-

Eye, Nose? and Throat.
'ised edition. By Ed-
1 E. B. Gleason, M. D.
ildren. 4th thousand.
,M.D.

_^ f Urine. Colored "Vo-

~ "gel Scale," with numerous illustrations. By

Lawrence Wolff, M. D. (Price, 75 cents.)
Essentials of Diagnosis. By S. Solis-Cohen, M. B.,
and A. A. Eshner, M.D. Illustrated. (Price,
$1.50 net.)
Essentials of Practice of Pharmacy. By L. E. Sayrb.

2d edition, revised.
Essentials of Bacteriology. 81 illustrations and five
plates. 2d edition, revised. By M. V. Ball, M. D.
Essentials of Nerrous Diseases' and Insanity. 48

illustrations. By John C. Shaw, M. D.
Essentials of Medical Physics. 155 illustrations. By

Fred J. Brockway, M. D. (Price, 81.00 net.)
Essentials of Medical Electricity. 65 illustrations.
By David D. Stewart, M. D., and Edwakd S.
Lawrance, M. D.

Price, Cloth, $1.00 per copy, except when otherwise noted.

*** For sale by all booksellers, or mailed to any address on receipt of price. Full descriptive catalogue
sent on application. * ' l^.- <. / „

At the present time, when the student is forced by the rapid progress ot
medical science to imbibe an amount of knowledge which is far too great to
permit of any attempt on his part to master it, a book which contains the
"essentials" of a science in a concise yet readable -form must of necessity be
of value.

Intended to assist Students to put together the knowledge they have already
acquired by attending lectures.

o

u

b 3

Saunders' New Aid Series of Manuals.

A MANUAL

SURGERY,

>
o

O -o

* J GENERAL AND OPERATIVE.

•4-1

rt rt BY
.5 w

S £ JOHN CHALMERS DaCOSTA, M.D.,

£ '/) Demonstrator of Surgery, Jefferson Medical College, Phila-

T3 delphia ; Chief Assistant Surgeon, Jefferson Medical

rt .-m College Hospital ; Surgical Registrar, Phila-

rt >-^ delphia Hospital, etc.

*s «

•g 5

g Vm One very handsome volume of over 800 pages, with 188 Illustra-
tions in text and 13 Plates in Colors and Tints.

g en (Double Number.)

o £* PRICE, CLOTH, $2.50 net.

§ "3 A new manual of the Principles and Practice

„ ~ of Surgery, intended to meet the demands of

^ -g students and working practitioners foramedium-

£ Q sized work, which will embody all the newer

^ > methods of procedure detailed in the larger

Jj ^ text-books. The work has been written in a

H t! concise, practical manner, and especial attention

5- ' has been given to the most recent methods of

treatment. Illustrations have been freely used

to elucidate the text.

A Syllabus of Lectures

ON THE

PRACTICE OF SURGERY,

Arranged in Conformity with

Tie American Text-Boot of Snriery.

BY

NICHOLAS SENN, M. D., Ph.D.,

Professor of Surgery in Rush Medical College, Chicago,
and in the Chicago Polyclinic.

PRICE, $2.00.

Sent post-paid on receipt of price.

This latest work of its eminent author, himself
one of the contributors to the " American Text-Book
of Surgery," has been carefully prepared from bis
unrivalled course of lectures to the students of Bush
Medical College, and is intended for use as a key or
supplement to the larger work.

The subjects are carefully grouped in tabular form,
those diseases and operations of a similar character
and requiring similar treatment being classed to-
gether, thereby greatly condensing the material and
lightening the labors of the student.

The Syllabus will prove also of exceptional value
as a surgical diagnosis and as an aid to the surgeon
in selecting the operations indicated.

ESSENTIALS

PHYSIOLOGY.

Since the issue of the first volume of the
Saunders Question=Compends,

OVER 160,000 COPIES

of these unrivalled publications have been sold.
This enormous sale is indisputable evidence
of the value of these self-helps to students
and physicians.

SAUNDERS' QUESTION-COMPENDS, NO. 1.

ESSENTIALS OF PHYSIOLOGY

ARRANGED IN THE FORM OF

QUESTIONS AND ANSWERS,

PREPARED ESPECIALLY FOR

STUDENTS OF MEDICINE.

BY

HOBART AMORY BARE, M.D.,

PROFESSOR OF THERAFEI i I< - ami MATERIA MEDICA IN THE JEFFERSON
MEDICAL COLLEGE OF I'll 1 1. A ln:i nil A ; PHYSICIAN To Till; JEF-
FERSON MEDICAL COLLEGE HOSPITAL; MEMBER OF THE
ASSOCIATION of AMERICAN PHYSICIANS.

FOURTH EDITION, THOROUGHLY REVISED AND ENLARGED.

i ONI AININQ

A SERIES OF HANDSOME PLATE [LLUSTBATIONS TAKEN FROM I in:
CELEBRATED "ICONSS NERVORUM CAPITIS" OF ARNOLD.

PHILADELPHIA:
\V. I',. SAUND E lis,

925 W \ i.Ni r Si REET.

1898.

Copyright, 1897,

BY

W. F. . SAUNDERS

Press of
W. B. Saunders, Philadelphia.

PREFACE TO FOURTH EDITION.

At the request of the publisher, and with the con-
sent of Dr. Hare, the work of revising this book for
the fourth edition has been undertaken by Dr. J. H.
Raymond. The original text has almost wholly been
retained, alterations being made only where necessary to
bring the subject under consideration abreast with the
teachings of the day.

(v)

Digitized by the Internet Archive

in 2010 with funding from
Columbia University Libraries

http://www.archive.org/details/essentialsofphysOOhare

PKKFACE TO FIRST EDITION.

At the present time, when the student is forced by the
rapid progress of medical science to imbibe an amount of
knowledge which is far too great to permit of an attempt
on his part to master it, any book which contains the
"essentials" of a science in a concise yet readable form
must of necessity be of value. The trite saying that "there
is no short road to knowledge " is, of course, as true as it
is old, and for this reason many of the medical profession
have looked with disfavor on books of this character, as
being the means by which students might attempt the
shorter path.

No one desires more than the writer that the depth and
scope of medical education may be increased, but in his
belief the evil at present in existence consists in the fact
that medical institutions, by granting a degree too early,
make the short road to knowledge the only one which the
student with the average amount of cerebral gray matter
can possibly travel. The evil lies with the small amount
of time required for the obtaining of the degree, not with
those books which are called into existence by the short-
ness of the medical curriculum.

( vii )

viii PREFACE.

The usefulness of arranging the subject in the form of
questions and answers will, the writer thinks, be apparent,
since the student, in reading the standard works on Phys-
iology, often is at a loss to discover the important points
to be remembered, and is equally puzzled when he attempts
to formulate ideas as to the manner in which the question
could be put in the examination-room.

A manual of this character is in no one way intended to
supplant any of the text-books, but to contain, as its title
declares, the essence of those physiological facts with which
the average student must be familiar.

After considerable thought, it has been considered
advisable to exclude points which may be called purely
anatomical, and which deprive some of the smaller books
on Physiology of the space which might otherwise be
occupied by purely physiological statements. The results
reached every day by physiological experimenters are
many of them so contradictory that no attempt to give
individual opinions or teachings has been attempted, the
statements made being supposed to represent those facts
most generally accepted and taught. The student will,
therefore, find statements which are not in accord with
those taught by his instructor, and it is for this purpose
that the interleaved edition has been published, in order
that individual teachings may be noted and remembered.
In the compilation of the facts here rehearsed, the standard
works of Landois, Yeo, Foster, Dalton, Baker, Hermann,
and Chapman have all been consulted.

CONTENTS.

PAGE

Proteids 18

Carbo-hydrates 20

The blood 21

Coagulation of blood 28

The heart 31

Respiration 48

The nervous mechanism of respiration .... 53

Digestion .......... 54

The stomach GO

Pancreatic digestion 66

The liver 68

Absorption .73

Animal heat 76

The kidneys 81

The urine 90

The skin 95

Secretion 97

The mammary glands 98

The bodily metabolism 98

General view of the most important substances used as food 99

Milk 99

The muscles 104

The nervous system 112

The physiology of the spinal nerves 117

The physiology of the cerebro-spiual nervous system . .118

The functions of the spinal cord 122

The medulla oblongata 128

The cranial nerves . 141

(IX)

CONTENTS.

The special senses .

The sensibility of the skin

The sense of taste .

The sense of smell .

The sense of sight .

Hearing ....

The voice and speech

The sympathetic nerve .
Generation and development .

Generative organs of the female

The male sexual organs .

Development .
The development of organs .

Vertebral column and cranium

Extremities

Heart and bloodvessels .

Nervous system

Eye

Ear

Nose. ....

Alimentary canal and organs

The foetal circulation

PAGE

145

146
147
148
149
158
161
165
167
168
171
178
179
179
180
180
181
182
183
183
183
184

PLATE I.

DESCRIPTION OF THE PLATES.

PLATE I.

POSITION AND COURSE OF THE CRANIAL NERVES WITHIN
THE SKULL.

This plate shows the course of the cranial nerves within the skull
and through the foramina of the dura mater, and the plexuses of
nerves accompanying the arteries at the hase of the brain.

The skull being removed by a horizontal section from the glabella
to the external occipital protuberance, the brain and tentorium cere-
belli are taken out, leaving in view the arteries and roots of the nerves
at the base of the brain.

A. — Superior part of the helix of the right and left ears.

15. — Skin and adipose tissue.

C. — Frontal portion of occipito -frontalis muscle.

1). — Temporal muscle.

E. — Occipital portion of the occipito-frontalis muscle, a. Frontal
artery. 6. Supraorbital artery, c. Anterior, and d, posterior
temporal arteries, e. Occipital artery.

F. — Frontal bone. /. Frontal crest, g. Groove for the superior lon-
gitudinal sinus.

G. — Parietal bone ; h, its anterior, and i, posterior inferior angles.

H. — Squamous portion of the temporal hone.

I. — Tabular portion of the occipital bone. k. Internal occipital pro-
tuberance.

K. — Crista galli.

L. — The dura mater covering the anterior cranial fossa, cerebral
ridges, and digital impressions, /, and the cribriform plate of
the ethmoid bone, m. n. Anterior portion of the f'al\ cerebri
with the superior longitudinal sinus, ■•.

(xi)

Xll DESCRIPTION OF THE PLATES.

31. — Middle cranial fossa, covered by dura inater. p. Posterior cli-
noid processes, q. Dorsum ephippii. r. Anterior clinoid
processes, s. Pituitary body and infundibulum. t. Dia-
phragm of the sella Turcica, u. Superior petrosal sinus.

N. — Posterior cranial fossa, v. Falx cerebelli. w. Torcular Hero-
phili. x. Lateral sinuses, y. Mastoid emissary vein. z.
Opening of the lateral sinus into the bulb of the internal
jugular vein.

O. — Foramen magnum.

P. — Lower portion of the medulla oblongata, a. Anterior median
fissure. @. Posterior median fissure, y. Central gray mat-
ter with central canal of the spinal cord. J. Anterior, and e,
posterior gray horns. £. Pyramids. ». Lateral columns.
Sh Posterior columns.

Q. — Vertebral arteries, i. Anterior spinal artery, x. Posterior in-
ferior cerebellar artery, x. Posterior spinal artery, /x. Basi-
lar artery, v. Branches to the pons. £. Anterior inferior
cerebellar artery, o. Internal auditory artery, it. Superior
cerebellar artery, p. Posterior cerebral artery.

K. — Internal carotids. <r. Posterior communicating artery, r. An-
terior choroid artery, v. Middle cerebral artery. <f>. Ante-
rior cerebral artery. %. Anterior communicating artery.

I. — Olfactory nerve.

II. — Optic nerve.

III. — Motor oculi nerve.

IV. — Pathetic nerve.

V. — Trifacial nerve.

VI. — Abducens nerve.

VII. — Facial nerve. 1. Its greater, and 2, lesser portions.

VIII. — Auditory nerve.

IX. — Glosso-pharyngeal nerve.

X. — Pneumogastric nerve.

XL — Spinal accessory nerve. 3. Its cranial, and 4, spinal roots.

XII. — Hypoglossal nerve.

The carotid and vertebral arteries are accompanied by sympathetic

plexuses, derived from the superior and inferior cervical, and some-
times from the superior thoracic ganglia.

PLATE II

DESCRIPTION OF THE PLATES,

PLATE II.

COURSE OF THE CRANIAL NERVES THROUGH THE FORAMINA
OF THE SKULL, AND IN THE ORBIT AND TEMPORAL FOSSA.

On tin' right side the semilunar ganglion, recurrent branches of the
first, second, and third divisions of the trifacial nerve, and the upper-
most nerves of the orbit are in view.

To the left are seen the conrse of the cranial nerves through the
foramina of the skull, t lie deeper nerves of the orbit, and the nerves
of the temporal fossa.

The calvarium being removed, the brain, together with the carotid
and vertebral arteries, is taken out.

To the right the dura mater and tentorium cerehelli are in their
natural position, the lateral and superior petrosal sinuses being
opened, but the meningeal layer of the dura mater of the middle
cranial fossa is removed, as is also the roof of the orbit, so that not
only the triangular plexus, semilunar ganglion, the first, second, and
third divisions of the trifacial, with their recurrent branches, hut also
the course of the supraorbital, lachrymal, and pathetic nerves may be
seen.

To the left, the dura mater which covers the base of the skull is re-
moved. The orbit, temporal fossa, tympanic cavity, internal auditory
meatus, and facial canal are exposed to view. The supraorbital,
lachrymal, and pathetic nerves are cut away, and the levator palpebral
superioris ami superior rectus muscles are divided and turned aside.

To the left, therefore, are seen the course of the cranial nerves
through the foramina of the skull ; the position and course of the
optic, nasal, superior branches of the motor oculi and the abducens
nerves ; the origin and course of the buccal, deep temporal, masse-
teric and anterior auricular nerves ; and finally the connections of the
facial and auditory nerves ; the course of the chorda tympani through
the tympanic cavity, and the position of the greater and lesser
superficial petrosal nerves on the upper surface of the petrous por-
tion of the temporal bone.

A. — P., and a — g, indicate the same structures as in the preceding

plate.
G. — Inferior margin of the parietal bone.

XIV DESCRIPTION OF THE PLATES.

H. — Squamous portion of the right temporal bone. h. Left cerebellar
fossa, i. Foramen magnum, k. Left innominate process.
/. Left jugular process, m. Jugular notch, n. Left poste-
rior, and o, anterior condyloid foramina.

K. — Petrous portion of the left temporal bone. /;. Sigmoid fossa.
q. Mastoid foramen. r. Mastoid cells, s. Semicircular
canals partly visible and partly cut away. t. Internal audi-
tory meatus, u. Tympanic cavity, v. Head of the malleus.
w. Incus, x. Posterior lacerated foramen, y. Apex of the
petrous portion of the temporal bone. z. Petro-sphenoidal
ligament.

Li, — Sphenoid bone. a. Clivus Blumenbachii. 8. Posterior clinoid
processes, y. Olivary process. J. Left great wing of the
sphenoid bone partly cut away. e. Foramen spinosum. £.
Foramen ovale. ». Foramen rotundum. S-. Roots of the
right lesser wing of the sphenoid bone. t. Anterior lacerated
foramen, x. Optic foramen, between the roots of the lesser
wing of the sphenoid bone.

31. — Cribriform plate of the ethmoid bone. X. Anterior ethmoidal
foramen.

N. — Inner surface of the temporal muscle.

O. — Upper border of the external pterygoid muscle.

P. — Condyle of the inferior maxilla.

Q. — Dura mater, ft. Anterior portion of the falx cerebri and of the
superior longitudinal sinus, v. Opening for the passage of
the trunk of the trifacial nerve. £. Posterior portion of the
falx cerebri, o. Right lateral sinus, ir. Superior petrosal
sinus, p. Dura mater covering the posterior cranial fossa.

K. — Lower portion of the medulla oblongata.

S. — Vertebral artery. On the left it may be seen beneath the con-
dyloid portion of the occipital bone ; and on the right it is
seen passing through the dura mater.

T. — Internal carotid. <r. The second, t, third, and u, fourth flexures
of the left internal carotid.

U. — Middle meningeal artery. On the left side it is divided near the
foramen spinosum. <p. The anterior branch, and ^, poste-
rior branch of the middle meningeal artery, which last sends
a small petrosal branch into the anterior part of the petrous
portion of the temporal bone.

V. — Posterior deep temporal artery, branch of the internal maxillary.

DESCRIPTION OF THE PLATES. XV

W. — Ophthalmic artery. ^. Lachrymal artery. M. Muscular
branches, aa. Ciliary arteries. 66. Supraorbital artery,
ce. Ethmoidal artery, dd. Ophthalmic artery continuing

course to the inner canthus.
X. — Pituitary body and part of the infundibulum.

Y.— The eyeball.

Z. — External rectus muscle. .1.1. Internal rectus muscle. BB.
Superior oblique muscle. CC. Levator palpebral superioris

musole. DD. Superior rectus muscle.
I. — Olfactory nerve. 1. Olfactory tract, and 2, bulb of the left side.

3. Filaments of the right olfactory nerve, en sheathed by the
dura mater, entering the nasal cavity through the cribriform
plate of the ethmoid bone.

II. — Optic nerve. 4. Its sheath. On the left side the course of the
optic nerve may 1m- seen as tar as the eyeball.

III.— Motor oculi nerve. "). Superior branch, going to the superior
rectus and levator palpebrae superioris muscles. 6. Inferior
branch.

IV. — Right pathetic nerve. 7. Communicating branch of the first
division of the tilth to the pathetic nerve, which runs in its
.-heath, from whence it soon passes to the internal branch oi
the supratrochlear nerve. 8. Distribution of the pathetic
nerve to the superior oblique muscle.

V. — Trunk and triangular plexus of the trifacial nerve. 9. Semi-
lunar (or Sasserian) ganglion of the fifth pair. 10. Small
accessory ganglion, sometimes found in the triangular plexus
near the semilunar margin of the semilunar ganglion. 11.
First division of the trifacial. 12. Recurrent branch,
which runs around the pathetic and divides into two
branches, (13), which go as far as the lateral sinus. 14.
Lachrymal nerve. 15. Supraorbital nerve. 1(>. Frontal
nerve. 17. Supratrochlear nerve. 1 8. Two filaments which
go to the supratrochlear nerve, lit. Nasal nerve. 20. Sensory
root of the ophthalmic ganglion. 21. Long ciliary nerves.
21*. Short ciliary nerves, coming from the ophthalmic gang-
lion. 22. Nasal nerve. 23. Infratrochlear nerve. 24.
Second division of the trifacial. 25. Recurrent branch of
the second division of the fifth. 25*. Its junction with the
recurrent branch of the third division of the fifth. 26. Third
division of the trifacial. On the left side it may be seen

XVI DESCRIPTION OF THE PLATES.

passing through the foramen ovale. 27. Recurrent branch
of the third division of the fifth nerve, which runs within
the cranium along the posterior margin of the middle menin-
geal artery, joins the recurrent branch of the second division
of the fifth (25*), and gives off a lesser anterior petrosal
branch (27*), which accompanies the anterior petrosal artery
into the anterior part of the petrous portion of the temporal
bone, while it goes to the posterior part of the petrous por-
tion of the temporal bone with the posterior branch of the
middle meningeal artery, or a special posterior petrosal
branch of this artery. The origin of this recurrent nerve is
shown in the first figure of the fourth plate. 28. Superior
root of the auriculo-temporal nerve. 29. Masseteric nerve.
30. Posterior deep temporal nerve. 31. External pterygoid
nerve. 32. Buccal nerve. 33. Anterior deep temporal nerve.

VI. — Abducens nerve. On the left side its course may be seen on
the outer side of the internal carotid and through the ante-
rior lacerated (34) foramen. 35. Distribution of the abducens
nerve to the external rectus muscle of the eye.

VII. — Facial nerve. 36. Its greater, and 37, lesser portions. 38.
The internal, and 39, external communications of the facial
with the auditory nerve. 40. Geniculate ganglion. 41.
Greater superficial petrosal nerve. 42. Chorda tympaui
nerve.

VIII. — Auditory nerve.

IX. — Grlosso-pharyngeal nerve. 43. Lesser superficial petrosal nerve.

X. — Pneumogastric nerve. 44. Superior vagal ganglion, or ganglion
of the Root.

XI. — Spinal accessory nerve.

XII. — Hypoglossal nerve.

PLATE III.

DESCRIPTION OF THE PLATES. xvn

PLATE III.

THIS WITH PLATE IV. GIVES AN INNER AND POSTERIOR VIEW
OF THE CRANIAL AND CERVICAL NERVES, AND THE
CAROTID AND VERTEBRAL ARTERIES, BOTH WITHIN AND
OUTSIDE OF THE CRANIUM, AND OF THE SPINAL CANAL.

The distribution of the nerves of the nasal septum, course of the
posterior crauial and superior cervical nerves, and the position of the
superior cervical ganglion and sympathetic plexuses on the arteries
of the head are illustrated in this diagram.

The right side of the head and half of the cerebrum, cerebellum,
medulla and spinal cord are removed by a perpendicular section ; the
skull and the bodies of the cervical vertebrae, together with the rectus
capitis anticus major and minor and longus colli muscles. The basilar
process of the occipital and posterior part of the body of the sphenoid
bones are removed ; the spinal and carotid canals, and the condyloid
and posterior lacerated foramina are opened, the osseous and carti-
laginous nasal septum cut away, and the mucous membrane of the
pharynx and palate and the genio-hyo-glossus muscle are either partly
or wholly removed. Therefore the following structures are seen:
firstly, the spinal canal covered by the dura mater, and the vertebral
vessels and roots of the cervical nerves ; secondly, the posterior cranial
fossa and the recurrent branch of the vagHS nerve, the hypoglossal,
spinal accessory, vagus and glosso-pharyugeal nerves, both within
and outside of the cranium, and the superior cervical ganglion ;
thirdly, the cavities of the pharynx and larynx, hard and soft palate
and the tongue with its nerves ; finally, the common carotid lying
between the pharynx and vertebra?, the internal and external carotids
and the sympathetic plexuses accompanying the carotid and vertebral
arteries.

A. — Gr. — Cervical vertebra? from the first to the seventh, n. Arch of
the vertebra? sawed through the centre, h. Left apex of the
spinous processes, c. Posterior root of the transverse pro-
cesses.

Jf. Occipital bone. d. Left condyle, c. Anterior condyloid foramen.

f. Tabular portion of the occipital bone. g. External, and

XV111 DESCRIPTION OF THE PLATES.

h, internal occipital protuberances, i. Foramen magnum.
k. Posterior cranial fossa, covered by dura mater.

I. — Interior portion of parietal bone.

K. — Temporal bone. /. Petrous portion, m. Carotid canal, n. In-
ternal auditory meatus, o. Squamous portion of the temporal
bone covered by dura mater.

Ii. — Sphenoid bone. p. Its body partly removed, q. Sphenoidal
sinus, r. Lesser wing. s. Greater wing, covered by dura
mater, t. Middle cranial fossa, u. Optic foramen.

M. — Frontal bone. v. Its vertical plate, w. Frontal sinus, x. Or-
bital plate, covered by dura mater, y. Digital impressions
and cerebral ridges, z. Anterior cranial fossa.

N. — Cribriform plate of the ethmoid, a. Crista galli sawed through
the centre.

O. — Nasal bone.

P. — Palate process of the superior maxillary. 6. Anterior palatine
canal.

Q. — Horizontal plate of the palate bone. y. Posterior palatine
canal.

R. — Inferior maxillary, sawed through the centre. 5. Genial
tubercles.

S. — Incisor teeth.

T. — Left superior canine tooth.

XJ. — Hyoid bone. s. Body. £. Greater cornu. w. Lateral thyro-
hyoid ligament.

V. — Trapezius, W, splenius capitis, X, biventer cervicis, Y, semi-
spinalis colli, and Z, interspinales muscles. A. Rectus capi-
tis posticus major, and B, minor muscles.

r. — Orbicularis oris muscle.

A. — Genio-hyo-glossus muscle, partly removed so that the distribution
of the lingual and hypoglossal nerves, the course of the ranine
and sublingual arteries, and the site of the sublingual gland
and Wharton's duct may be seen. 9. Internal, and «, ex-
ternal layers of fibres of the genio-hyo-glossus. E. Longitu-
dinal, and z, inferior transverse fibres of the lingualis, H,
genio-hyoid, and ©, mylo-hyoid muscles.

;. — Anterior belly of the digastric.

K. — Levator palati, A, superior, M, middle, and N, inferior constric-
tors of the pharynx, s. Longitudinal fibres of the oesophagus.

DESCRIPTION OF THE PLATES. XIX

O. — Trachea, *. Rings of the trachea.

n. Larynx. x. Cricoid, and (x, thyroid cartilages. ». Epiglottis.
£. Ventricle of the larynx, o. Arytsenoideus muscle.

p. — Isthmus of the thyroid gland.

Z. — Wharton's duct. T. Sublingual gland.

r. — Tongue, m. Circumvallate, and p, fungiform papillae, a-. Root
of the tongue.

* — Palate, t. Soft palate, v. Mucous membrane of the hard pal-
ate. <f>. Incisive papilla.

X. — Roof of the pharynx, x- Pharyngeal orifice of the Eustachian
tube. -^. Mucous glands of the roof of the pharynx.
a). Eustachian eminence.

y. — Left posterior nares. n. Membrane of the nasal septum.

AA. — Dura mater, an. Anterior, and bb, posterior part of the falx
cerebri, cc. Tentorium cerebelli. dd. Posterior end of the
superior longitudinal sinus, ee. Superior petrosal sinus.
ff. Sigmoid portion of the lateral sinus.

BB. — Dura mater of the spinal cord.

CC. — Vertebral artery, gg. Its first, hh, second, and ii, third flexures.

DD. — Inferior thyroid artery.

EE. — Common carotid.

FF. — External carotid.

GG. — Superior thyroid artery.

HH. — Lingual artery, kk. Sublingual artery. //. End of the
ranine artery.

II. — Facial artery.

KK. — Ascending pharyngeal artery, mm. Pharyngeal, and nn, ba-
silar branches.

(IiL.) — Internal maxillary artery, oo. Arteries of the nasal sep-
tum, pp. Descending palatine artery.

MM. — Internal carotid, qq. Cowper's flexure, which is sometimes
found. rr. Its first, ss, second, tt, third, and uu, fourth
flexures, vv. Posterior communicating artery, uno. Anterior
choroid artery, xx. Middle cerebral or Sylvian artery.
yy. Anterior cerebral artery, zz. Ethmoidal branch of the
ophthalmic artery, anastomosing with the nasal branches of
the internal maxillary.

NN. — Trunk of the vertebral vein, which receives the cervical part
of the vertebral sinus, (OO), between the fifth and sixth
cervical vertebra. PP. — Vertebral vein accompanying the

XX DESCRIPTION OF THE PLATES.

vertebral artery through the vertebral foramina and con-
nected by many transverse branches with the vertebral sinus.

QQ. — Anastomosis of the superior and inferior thyroid arteries.

I. — Olfactory nerve. 1. Olfactory filaments of the nasal septum in-
closed in fibrous sheaths.

II. — Optic nerve.

III.— Motor oculi nerve.

IV. — Pathetic nerve.

V. — Trifacial nerve.

First division. 2. Nasal nerve.

Second division. 3. Nasal nerves. 4. Branch to the hard pal-
ate, passing through the anterior palatine canal.
5. Pharyngeal nerves.
Third division. 6. Lingual nerve. 7. Lingual branches.

VI. — Abducens nerve.

VII. — Facial nerve.

VIII. — Auditory nerve.

IX. — Glosso- pharyngeal nerve. 8. The petrous ganglion. 9. Junc-
tion with the jugular branch of the superior cervical gang-
lion. 10. Branch joining the superior pharyngeal branch
of the vagus. 11. Pharyngeal branches. 12. Lingual
branch. 13. Branches going to the circumvallate papillae.
14. Branches supplying the mucous membrane between the
circumvallate papillae and the epiglottis.

3L — Pneumogastric nerve. 15. Superior vagal ganglion. 16. Junc-
tion with the jugular branch of the superior cervical gang-
lion. 17. Recurrent branch of the vagus. 18. Its lesser
division going to the occipital sinus, and the greater branch,
19, going to the sigmoid sinus. 20. Superior pharyngeal
branch. 21. Inferior vagal ganglion, or ganglion of the
Trunk. 22. Inferior pharyngeal branch passing to the pha-
rynx between the internal and external carotids. 23. Supe-
rior laryngeal nerve. 24. External branch. 25. Its junc-
tion with the sympathetic nerve. 26. Internal branch of
the superior laryngeal nerve. 27. Branches distributed to
the raucous membrane of the larynx and epiglottis. 28.
Junction with the inferior laryngeal nerve. 29. Vagus nerve
in the neck. 30. Inferior laryngeal nerve. 31. Its inoscu-
lation with the sympathetic. 32. Oesophageal branches.
33. Tracheal branches. 34. Laryngeal branch.

DESCRIPTION OF THE PLATES. XXI

XI. — Spinal accessory nerve. 35. Its internal, and 36, external
divisions.

XII. — Hypoglossal nerve. 37. Its inosculation with the first cervical
nerve and superior cervical ganglion. XII*. — Branches of
the hypoglossal to the genio-hyo-glossus and genio-hyoid
muscles.

XIII. — XIX. — Seven superior cervical nerves. 38. Their anterior, and
39, their posterior roots. 40. Ganglia on the posterior roots
of the cervical nerves. 41. Anterior division of the first,
second, third, and fourth cervical nerves. 42. Communi-
cating branches of these nerves, constituting the cervical
plexus. 43. Principal root of the phrenic nerve, coming
from the anterior division of the fourth cervical nerve.

XX. — Superior cervical ganglion. 44. Carotid nerve. 45. Its internal
inferior branch. 46. Carotid plexus. 47. Cavemosus plexus,
from which are given off branches to the abdncens (48), to
the ophthalmic division of the fifth (49), and to the cerebral
and ophthalmic arteries (50). 51. Jugular nerve, forming a
junction with the glossopharyngeal and vagus nerves. 52.
Nerve uniting the hypoglossal and first cervical nerves. 53.
Trunk inosculating with the cervical plexus. 54. Junction
of the superior cervical and inferior vagal ganglia. 55. Sym-
pathetic trunk to the external carotid, which is often com-
posed of two or three branches. 56. Superior part of the
trunk, from which branches go to the external carotid (57),
and to the carotid plexus (58). (59.) Inferior part of the
trunk, which gives branches to the facial (60), lingual (61),
and thyroid arteries (62). 63. Branch going to the carotid
ganglion (64), which sends very delicate branches to the
common carotid artery (65). 66. Branches to the external
branch of the superior laryngeal, and 67, to the phrenic
nerves. 68. Superior cardiac nerve, arising from the cer-
vical sympathetic trunk by several roots. 69. Its commu-
nication with the inferior laryngeal nerve. 70. Middle
cardiac nerve, uniting with the superior cardiac nerve.

XXI. — Upper portion of the first thoracic ganglion. 71. Sympathetic-
branches to the vertebral artery. 72. Sympathetic plexus
on the vertebral artery. 73. Sympathetic plexus on the
inferior thyroid artery.

XX11 DESCRIPTION OP THE PLATES,

PLATE IY.
Fig. I.

This diagram shows the trifacial, lateral nasal, and palatine nerves,
the spheno- palatine and otic ganglia, and the facial nerve in the facial
canal, seen from the inside.

The skull and posterior part of the head, parts of the neck, and
most of the petrous portion of the temporal and the sphenoid bones
are removed ; the facial canal and tympanic cavity are opened to
view, the internal carotid artery and carotid canal, the cartilaginous
portion of the Eustachian tube, roof of the pharynx and levator
palati muscle, the nasal septum, and posterior part of the hard
palate are cut away ; the pterygo-palatine fossa and canals are
shown, and the mucous membrane of the nose is partly removed.

Therefore the internal auditory meatus, the facial canal, the osseous
portion of the Eustachian tube and the tympanic membrane, the ear
ossicles and their muscles, the course of the facial nerve through the
petrous portion of the temporal bone, the inner surface of the trunk
of the trifacial nerve and its ganglion, with its first, second, and third
divisions, the otic and spheno-palatine ganglia, the nerves of the palate,
and the lateral wall of the nose with the distribution of the nerves of
the first and fifth pairs to its mucous membrane are shown.
A. — Petrous portion of the temporal bone. a. Bottom of the inter-
nal auditory meatus, and b, interior of the facial canal, c.
Superior margin, and d, inner surface of the petrous portion
of the temporal bone.
B. — Sphenoid bone. e. Foramina spinosum,y, ovale, and g, rotun-
dum opened from within, h. Pterygoid process, with the
internal plate partly removed, i. Hamular process, k.
Inner extremity of the lesser wings. /. Optic foramen.
C. — Lower part of the vertical plate of the frontal bone. m. Frontal

sinus.
D. — Ethmoid bone. n. Posterior ethmoidal cells, o. Cribriform
plate, p. Anterior ethmoidal foramen, q. Left nasal fossa.
E. — Left nasal bone.

F. — Palate process of the superior maxillary bone.
Gr. — Ramus of the inferior maxillary bone. r. Angle of the inferior
maxillary bone.

PLATE IV.

..

*tm.

DESCRIPTION OF THE PLATES. XXlii

H. — Tensor palati muscle turned forward.
I. — Interna] pterygoid muscle.
K. — Tensor tympani, and L, stapedius muscles.
31. — Upper end of the external carotid artery.
N. — Temporal artery.

O. — Internal maxillary artery, s. Inferior dental artery. /. Mid-
dle meningeal artery. u. Descending palatine artery, v.
Nasal artery cut.
I*. — Posterior auricular artery.

Q. — Dura mater, upper surface of the petrous portion of the temporal
bone, and the trifacial, pathetic, motor oculi and abduceiis
nerves. K. — Inner surface of the tympanic membrane, and
the ear ossicles. w. The head, x, neck, and y, the manubrium
of the malleus, z. The incus, a. Stapes.
S. — Lateral wall of the nasal cavity. &. The superior, y, middle,
and £, inferior turbinated bones, t. The superior, £, mid-
dle, and n, inferior meatuses of the nose. S. Lateral carti-
lage, and «, ala of the nose. x. Mucous membrane covering
the superior and upper part of the middle turbinated bones
removed to show the course of the olfactory filaments through
the grooves of the ethmoidal turbinated bones, x. Mucous
membrane of the anterior inferior regions of the nares is
removed, showing the distribution of the nasal branches of
the fifth nerve. /*. Mucous membrane of the inferior meatus.
». Mucous glands.
T. — Mucous membrane of the hard and soft palate.
U. — The tongue. £. Lingual papilla?, o. Glands at the root of the

tongue.
V. — Parotid gland.

(I.) — Olfactory nerve. 1. Olfactory filaments of the wall of the nose
which have fibrous sheaths and run through grooves in tin
upper and middle turbinated bones, forming a network aim
sending delicate branches to the mucous membrane.
II. — Optic nerve.
III. — Motor oculi nerve.
IV. — Pathetic nerve.

V. — Trifacial nerve. 2. Common trunk. 3. Its lesser, and 4, its
greater roots. 5. Semilunar ganglion, (j. First or ophthal-
mic division of the fifth nerve. 7. Nasal nerve. B.
Branch to the nasal septum severed (vid. Plate III., 2). 9.
Branch to the lateral surface of the nares. 10. External

XXIV DESCRIPTION OF THE PLATES.

branch (vid. Plate VIII., 7). 11. Second or superior maxil-
lary division of the fifth. 12. Naso-palatine nerve. 13.
Posterior palatine nerves. 14. The anterior palatine nerve.
15. Superior, and 16, inferior nasal nerves. 17. Spheno-
palatine ganglion (Meckel's). 18. Greater deep petrosal
nerve. 19. Greater superficial petrosal. 20. Vidian nerve.
21. Ascending branches, and 22, branch from the ganglion
to the nose. 23. Third or inferior maxillary division of the
fifth. 24. Recurrent branch piercing the otic ganglion and
accompanying the middle meningeal artery within the
cranium (rid. Plate II., 27). 25. Auriculotemporal nerve,
arising by two roots, between which passes the middle men-
ingeal artery. 2(3. Inferior dental nerve. 27. Lingual
nerve. 28. Junction of the chorda tympani and lingual
nerves. 29. Internal pterygoid nerve. 30. Branches to
the tensor palati, and 31, to the tensor tympani muscles,
coming from the pterygoid nerve and piercing the otic gang-
lion. 32. Otic ganglion. 33. Lesser superficial petrosal,
coming from the tympanic nerve. 34. Sympathetic root
of the otic ganglion. 35. Branch to the tensor tympani
leaving the otic ganglion. 36. Branch proceeding to the
auriculotemporal nerve.

VI. — Abducens nerve.

VII. — Facial nerve. 37. Genu of the facial nerve. 38. Greater
superficial petrosal nerve. 39. Junction with the lesser
superficial petrosal nerve, which arises from the tympanic
nerve. 40. Branch to the stapedius muscle. 41. Chorda
tympani.

Fig. II.

Showing, from behind, the course of the facial, glossopharyngeal,
pneumogastric, spinal accessory, and hypoglossal nerves in the
cranial bones, and of the auricular branch of the vagus in the
petrous portion of the right temporal bone.

The occiput of the right side of the head is removed by a transverse
section, opening the condyloid and posterior lacerated foramina, and
the facial canal and auricular fissure from behind.

Therefore the course of the hypoglossal, spinal accessory, vagus
and glosso-pharyngeal nerves through the foramina of the skull, the
ganglia of the vagus and glosso-pharyngeal nerves, the auricular
branch of the vagus and its junction with the facial nerve are seen.

DESCRIPTION OF THE PLATES. XXV

A. — Occipital bone. <i. Basilar process. 6. The condyle, c. Anterior

condyloid foramen.

B. — Body of the sphenoid bone covered by dura mater.

C — Petrous portion of tbe temporal bone. </. Its superior internal
margin, e. Inner surface, f. Internal auditory meatus, g.
Cavity of the tympanum, It, mastoid cells, and i, posterior
part of the facial canal from behind, k. ('anal for the chorda
tympani. /. Auricular fissure. m. Mastoid process, u.
Styloid process, o. Stylo-mastoid foramen, p. Upper part
of the bead of the malleus. 7. The body, and r, the short
process of the incus.

D. — Posterior surface of the ear.

E. — Skin and adipose tissue.

F. — Sterno-cleido-mastoid muscle, cut perpendicularly.

G. — Posterior belly of the digastric muscle, also divided.

H. — Posterior surface of the roof of the pharynx, a. Acinous mucous
glands of the pharynx, t. Superior constrictor muscle of
the pharynx.

I. — Internal carotid.

K. — Internal jugular vein, cut off above so that the course of the
auricular branch of the vagus nerve may be seen.

L. — Occipital, and M, posterior auricular arteries.

VII. — Facial nerve. 1. Chorda tympani. 2. Posterior auricular
nerve. 3. Small branches going to the posterior belly of the
digastric muscle.

VIII. — Auditory nerve.

IX. — Glossopharyngeal nerve. 4. The petrous ganglion. 5. Branch
joining the auricular branch of the vagus. 6. Pharyngeal
branches of the glosso-pharyngeal nerve.

X. — Pneumogastric nerve. 7. Superior vagal ganglion. 8. Recur-
rent branch of the vagus, divided transversely. 9. Auricular
branch of the vagus. 10. Its communication with the facial
nerve in the facial canal. 11. Its communication with the
posterior auricular nerve. 12. Its auricular branches. 13.
Inferior vagal ganglion.

XI. — Spinal accessory nerve. 14. Its internal, and 15, its external
divisions.

XII. — Hypoglossal nerve.

XIII. — Carotid nerve and the upper part of the superior cervical
ganglion.

xxvi DESCRIPTION OF THE PLATES.

PLATE Y.

ILLUSTRATION OF CRANIAL AND CERVICAL NERVES, THE
NERVES ACCOMPANYING THE CAROTID AND VERTEBRAL
ARTERIES, BOTH WITHIN AND OUTSIDE OF THE CRANIUM,
AND THE SPINAL CORD SEEN FROM THE OUTSIDE.

This plate shows, firstly, the origin of the cranial and cervical
nerves of the right side, with the exception of the first and sixth
pairs ; secondly, the course of the cervical nerves between the cervical
vertebrae, the spinal ganglia, the breaking up of the nerves into their
anterior and posterior divisions, and their inosculations amongst
themselves and with the superior cervical ganglion ; then the course
and part of the distribution of the third, fourth, fifth, ninth, tenth,
eleventh, and twelfth pairs of nerves outside of the cranium, and
the roots of the ophthalmic and spheno-palatine ganglia and the
sympathetic plexuses on the vertebral and internal carotid arteries.

To show these parts the scalp, occipital, frontal, parietal, mastoid
and petrous portions of the temporal, the greater and lesser wings of
the sphenoid, the malar and posterior portions of the inferior maxillary
bones of the right side, the spinous and transverse processes, and the
arches of the cervical vertebrae, together with the skin and superficial
muscles of the neck, the muscles and vessels of the face and temples,
and the thyroid and salivary glands are removed ; the intervertebral,
condyloid, and posterior lacerated foramina, spinal canal, internal
auditory meatus, carotid canal, Eustachian tube, pterygo-palatine
fossa, Vidian canal and the antrum of Highmore are opened ; the
right half of the cerebellum and cerebrum, together with the corpus
striatum, is removed ; while the spinal cord, medulla oblongata, pons
Varolii, crus cerebri, right optic thalamus and corpora quadrigemina
remain intact.

A. — G. — Cervical vertebrae from the first to the seventh, a. Left
portion of the spinous processes, b. Right transverse pro-
cesses, c . Anterior, and d, posterior roots of the transverse
processes.
JJ. — Occipital bone. e. Its tabular portion. /. External occipital
protuberance, g. Right condyle, h. Anterior condyloid
foramen, i. Posterior lacerated foramen.

PLATE V.

DESCRIPTION OF THE PLATES. XXV11

I.— Petrous portion of the right temporal bone. k. The posterior,
/, external, and m, superior semicircular canals, n. Cochlea.
o. Fenestra ovalis, and p, fenestra rotunda, q. Base of the
styloid process.

K. — Body of the sphenoid bone. r. Clivus Blumenbachii. s. In-
ternal plate of the pterygoid process.

L. — Parietal bone sawed through near the sagittal suture.

M. — Frontal bone.

N. — Superior maxillary bone. t. Antrum of High more.

O. — Inferior maxillary bone.

P. — Molar, and Q, bicuspid teeth of the upper jaw.

R. — Right inferior canine tooth.

S. — Greater cornu of the hyoid bone.

T. — The trapezius, U, splenitis, V, biventer cervicis, W, Semi-
spinalis colli, X, interspinals, Y, rectus capitis posticus
major, and Z, minor muscles of the left side.

AA. — Right rectus capitis anticus major muscle.

BB, and CC. — Inferior, DD, middle, and EE, superior con-
strictor muscles of the pbarynx.

FF. — Stylo-pharyngeus muscle.

GG. — The stylo-hyoid, HH, genio-hyo-glossus, JJ, genio-hyoid,
and KK, mylo-hyoid muscles. EL. — The hyo-glossus
muscle, partly cut away to show the course of the lingual
artery and lingual branch of the glosso-pharyngeal nerve.

MM. — The thyro-hyoid, and NN, crico-thyroid muscles.

OO. — Levator palati muscle. PP. — Tendon of the tensor palati
muscle.

QQ. — Levator anguli oris muscle.

KR. — The levator palpebral superioris, SS, superior, and TT, in-
ferior recti, and UU, inferior oblique muscles of the eye.

W.— The eyeball.

WW. — The upper, and XX, lower lids, cut through perpendicu-
larly.

YY. — The tongue, u. Fungiform papillse. v. Mucous membrane
of the cheek.

ZZ. — The larynx. A. — Trachea.

B. — Oesophagus.

r. — Eustachian tube.

A. — Common carotid.

E. — External carotid.

XXvili DESCRIPTION OF THE PLATES.

Z. — Superior thyroid artery, w. Superior laryngeal artery, x. Thy-
roid branches severed, y. Muscular branches.

H. — Lingual artery.

©. — Origin of the facial artery.

I. — Ascending pharyngeal artery.

K. — Internal maxillary artery, z. Posterior dental artery, a. Infra-
orbital artery. /?. Descending palatine artery, y. Nasal
artery.

A. — Internal carotid. S\ — Its first, t, second, £, third, and », fourth
flexures.

M. — Ophthalmic artery.

N. — The posterior communicating, O, anterior choroid, n, middle
cerebral, and P, anterior cerebral arteries of the right side.
2. Anterior cerebral artery of the left side.

T. — Vertebral artery. $. Its first, i, second, and x, third flexures,
x. Spinal branches, /t*. The right, and v, left posterior
inferior cerebellar arteries. £. Internal auditory artery,
o. Right superior cerebellar artery, it. The right, and p, left
posterior cerebral arteries. <r. Inferior thyroid artery.

T. — Dura mater of the spinal cord.

<j>. — Tentorium cerebelli. t. Superior petrosal sinus.

x — Dura mater of the brain.

•V. — Cervical spinal cord.

n. — Medulla oblongata, y. Stria? medullares. <p. Sinus rhomboidalis.

AA. — Cerebellum. ^. Inner surface of the left hemisphere. •*. Arbor
vita?. &>. Fourth ventricle, aa. Valve of Vieussens, or su-
perior medullary velum. &%. The inferior, yy, middle, and
JS\ superior cerebellar peduncles, tt. Right side of pons

BB. — Right cms cerebri.

rr. — Corpora quadrigemina.

A a. Right optic thalamus.

ee. — Fornix. ££. Right cms of the fornix. «u. Foramen of Monro.
99-. Body of the fornix, u. Septum lucidum.

ZZ. — Corpus callosum divided longitudinally through the centre,
xx. Its genu, XA, body, and fx/x, splenium.

hh. — Inner surface of the left cerebral hemisphere, w. The frontal,
oo, parietal, and irir, occipital lobes, pp. Gyrus fornicatus.

II. — Optic nerve. 1. Its origin from the optic thalamus. 2. Optic
tract. 3. Orbital portion of the optic nerve.

DESCRIPTION OF THE PLATES. XXIX

III. — Motor oculi. 4. Superior branch to the superior rectus and
levator palpebrae superioris muscles. 5. Inferior branch.
6. Motor root of the ophthalmic ganglion. 7. Branch to the
inferior oblique muscle.

IV. — Pathetic nerve. 8. Its origin. 9. Course of the pathetic nerve
above the pons and external to the cms cerebri. 10. Its
course along the upper border of the ophthalmic division of
the trifacial nerve.

V. Trifacial nerve. 11. Its lesser, and 12, greater roots. 13. Semi-
lunar ganglion. 14. First or ophthalmic division of the
fifth. 15. Supraorbital nerve. 16. Lachrymal nerve cut
away. 17. Nasal nerve. 18. Sensory root of the ophthalmic
ganglion. 19. Long ciliary nerves. 20. Ophthalmic gang-
lion. 21. Its sympathetic root. 22. Short ciliary nerves.
23. The superior, and 24, inferior fasciculi of ciliary
nerves. 25. Second division or superior maxillary nerve.
26. Subcutaneous malae nerve severed. 27. Infraorbital
nerve. 28. Posterior dental nerves. 29. Anterior dental
nerve severed. 30. The iuferior palpebral, lateral nasal, and
superior labial nerves. 31. Naso-palatine nerve. 32. Spheno-
palatine ganglion. 33. Greater superficial petrosal nerve.
34. Greater deep petrosal nerve. 35. Posterior superior
nasal nerve. 36. Palatine nerves. 37. Third division or
inferior maxillary nerve. 38. Auriculotemporal nerve. 39.
Masseter nerve. 40. Posterior deep temporal nerve. 41.
Buccal nerve. 42. Inferior dental nerve. 43. Lingual nerve,
the lingual part of it being reflected to show the distribution
of the hypoglossal nerve. 44. Lingual branches.

VI. — Abducens nerve severed.

VII. — Facial nerve. 45. Genu of the facial nerve. 46. Its junction
with the greater superficial petrosal nerve.

VIII. — Auditory nerve.

IX. — Glosso-pharyngeal nerve. 47. Petrous ganglion. 48. Tym-
panic nerve. 49. Branch joining the carotid nerve. 50.
Branches to the fenestra rotunda, and 51, to the fenestra
ovalis. 52. Branch going to the Eustachian tube. 53.
Lesser superficial, and 54, lesser deep petrosal nerves. 55.
Branches uniting with the branches of the superior cervical
ganglion, and with branches from the iuferior vagal ganglion.
56. Carotid plexus. 57. Branches running between the

XXX DESCRIPTION OF THE PLATES.

internal and external carotids to the carotid ganglion. 58.
Pharyngeal branches. 59. Branches to the stylo-pharyngeus
muscle. 60. Lingual branches.

X. — Pneumogastric nerve. 61. Superior vagal ganglion. 62. Branch
to the carotid plexus. 63. Inferior vagal ganglion. 64.
Superior laryngeal nerve. 65. External branch to the crico-
thyroid muscle. 66. Junction of this branch with a filament
from the superior cervical ganglion. 67. Internal branch of
the superior laryngeal nerve. 68. Trunk of the vagus in the
neck. 69. Inferior or recurrent laryngeal nerve, sending
branches to the oesophagus, trachea, and larynx.

XI. — Spinal accessory nerve. 70. Its spinal, and 71, cranial roots.
72. Course of the spinal root between the roots of the pos-
terior division of the first cervical nerve. 73. Its internal
division, uniting with the trunk of the vagus. 74. Its ex-
ternal division.

XII. — Hypoglossal nerve. 75. Its roots passing over the vertebral
artery. 76. A branch joining the first cervical, and 77, the
vagus nerves. 78. Descendens noni branch. 79. Thyro-
hyoid branch. 80. Branch to the genio-hyoid, and 81, the
stylo-glossus muscles. 82. Branches to the hyo-glossus, and
83, the genio-hyo-glossus and the muscles of the tongue
proper.

XIII. — First cervical nerve. 84. Its posterior root, which is crossed
by the spinal accessory nerve. 85. The posterior division
cut away. 86. Anterior division. 87. Muscular branch.

XIV. — Second cervical nerve. 88. Posterior root. 89. Spinal gang-
lion. 90. Posterior division severed. 91. Anterior division.
92. Branch joining the first cervical nerve and superior cer-
vical ganglion. 93. Branch to the rectus capitis anticus
major muscle. 94. Descending communicating branch. 95.
Communicans noni branch.

XV. — Third cervical nerve. 96. The posterior root divided and
reflected to show the course of the spinal root of the spinal
accessory nerve. 97. Branch joining the posterior root of
the fourth cervical nerve. 98. Spinal ganglion. 99. Pos-
terior division severed. 100. Anterior division. 101. Junc-
tion with the superior cervical ganglion. 102. Communicans
noni branch. 103. Ansa hypoglossi.

XVII. — Fifth cervical nerve.
XVIII. — Sixth cervical nerve.
XIX. — Seventh cervical nerve.

DESCRIPTION OF THE PLATES. X \ \ I

XVI. — Fourth cervical nerve. 104. Posterior root divided. 1".">.
Its junction with tbe posterior rool of the fifth cervical
nerve. 106. Spinal ganglion. 107. Posterior division
severed. 108. Anterior division. 109. Branch to the
longus colli muscle. 110. Trunk of the anterior division
severed.

f 111. Posterior root. 112. Spinal
ganglion. 113. Posterior division
severed. 114. Anterior division
severed. 115. Roots of the
phrenic nerve.
XX. — Posterior root of the eighth cervical nerve.

XXI. — Superior cervical ganglion. 116. Sympathetic branches to
the carotid ganglion. 117. Carotid ganglion. 118. Fila-
ments to the common and external carotid arteries. 119.
Branch to the carotid plexus. 120. Superior external
branch of the carotid nerve, from which the greater deep
petrosal nerve is given off. 121. Inferior internal branch
of the carotid nerve. 122. Sympathetic nerves on the
internal carotid within the cranium.
XXII. — Cervical sympathetic trunk. 123. Vertebral branch from
the inferior cervical and superior thoracic ganglia. 124.
Sympathetic plexus on the vertebral artery.

xxxii DESCRIPTION OF THE PLATES.

PLATE YI.

COURSE OF SOME OF THE NERVES OF THE FIFTH PAIR
THROUGH THE ORBIT, SUPERIOR MAXILLARY BONE AND
TEMPORAL FOSSA ; OF THE FACIAL AND CHORDA TYM-
PANI THROUGH THE PETROUS PORTION OF THE TEM-
PORAL BONE; OF THE POSTERIOR DIVISIONS OF THE
CERVICAL NERVES IN THE MUSCLES OF THE NECK, AND
THE SYMPATHETIC NERVES ACCOMPANYING THE EXTER-
NAL CAROTID ARTERY AND ITS BRANCHES.

This plate, which shows the nerves of the right side of the head,
illustrates first the course of the lachrymal from the first, subcutaneous
malae and infraorbital from the second, and the lingual and mylo-
hyoid from the third division of the fifth ; then the facial nerve
through the facial canal, and chorda tympani through the tympanic
cavity, and the distribution of the posterior divisions of the cervical
nerves to the muscles of the neck, and finally the sympathetic plexus
around the external carotid, and the roots of the submaxillary gang-
lion.

The skull is divided by a perpendicular section near the sagittal
suture, and the right side of it, with the dura mater, is removed ; the
greater wing of the sphenoid, malar, and periorbital bones, most of the
right half of the superior and inferior maxillae, the squamous portion
and external part of the mastoid process of the temporal bone, the
platysma, sterno-cleido-mastoid, sterno-hyoid, sterno-thyroid, omo-
hyoid, and external pterygoid muscles are cut away ; and the second
and third layers of cervical muscles are turned aside. Therefore,
the following structures are partly or wholly exposed to view : the
external surface of the brain, the parts of the eye adjacent to its
outer wall, the frontal and maxillary sinuses, the parts of the oral
cavity and temporal fossa adjoining the inner surface of the inferior
maxillary bone, the tympanic membrane and mastoid cells, submaxil •
lary and thyroid glands, larynx, trachea, pharynx, and oesophagus,
and the muscles of the neck with the vessels and nerves.

A. — G. — Cervical vertebrae from the first to the seventh, a. Trans-
verse processes, b. Superior, and c, inferior articular pro-
cesses.

PLATE VI.

DESCRIPTION OF THE PLATES. XX.xiii

H. — Occipital bone. d. Left upper part of tlie tabular portion of the

occipital bone. e. Lower part of the tabular portion of « »< -< -i -

pital bone.
I. — Temporal bone. f. Mastoid foramen, g. Mastoid cells, h.

Facial canal, t. Styloid process. k. Stylo-mastoid foramen.

/. Membrana tympani. m. Incus, n. Malleus, o. Eus-

tachian tube.
K. — Sphenoid bone. p. Body. q. External pterygoid plate, r.

Sphenoidal cells, s. Foramen spinosum. t. Foramen ovale.

The foramen rotundum is covered by dura mater.
L. — Frontal bone. u. Its orbital, and v, vertical plates, w. Frontal

sinus.
M. — Right parietal bone, sawed through near the sagittal suture.
N. — Superior maxillary bone. x. Inner wall of the antrum of High-
more, y. Canine tooth, z. Bicuspid teeth, a. Molar teeth.
O. — Inferior maxillary bone, sawed through perpendicularly near the

right canine tooth {&).
I*. — Insertion of the sternocleidomastoid mnscle.
Q. — Splenitis capitis muscle cut transversely near its insertion {y).

\\. Trachelo mastoid muscle similarly cut ($). S. Com-

plexus and biventer cervicis muscles, detached and turned

aside from their origins. T. Semispinalis colli. U. Upper

part of the muPifidus spina?. V. Rectus capitis posticus

major. W. Inferior, and X, superior oblique muscles.

Y. Rectus capitis lateralis. Z. Intertransversales muscles.
A. — Rectus capitis anticus major. B. Scalenus anticus.
r. Posterior belly of the digastric. A. Stylo-hyoid. E. Styloglossus.

z. Internal pterygoid.
H. Anterior belly of the digastric. ©. Mylo-hyoid. I. Ceiiiodiyoid.

K. Hyo-glossus.
A. Thyro hyoid. M. Cricothyroid.
N Inferior constrictor of the pharynx, e. Its cricoid, and 6, thyroid

origins.
H. Levator palpebrae superioris and superior rectus muscles. n

External rectus muscle. rr. Inferior rectus muscle. p.

Inferior oblique muscle.
2. Eyeball. T. Lachrymal gland.
T. Dura mater. ». Lateral sinus.
♦. Cerebrum. 3-. The frontal, t. parietal, x, temporo sphenoidal, and

\, occipital lobes, ju. External part of the fissure of Sylvias.

v. Its vertical, and £, horizontal limbs.

XXXIV DESCRIPTION OF THE PLATES.

X. The tongue, o. Mucous membrane of the cheek.

y. Sublingual gland. ft. Submaxillary gland. *Wharton's duct.

AA. Thyroid gland.

BB. Larynx, ir. Thyroid cartilage, p. Cricoid cartilage.

CC. (Esophagus.

DD. Upper part of the common carotid.

EE. External carotid.

FF. Superior thyroid artery, a-. Its thyroid branches.

(jrG. Lingual artery.

Hll. Facial artery, t. Ascending palatine artery, v. A muscular

branch. <p. Submental artery.
II. Occipital artery, x- Descending cervical branches. Y. Menin-
geal branch. &>. Distribution of the artery to the occiput.
KK. Posterior auricular artery.
LL. Temporal artery.

MM. Internal maxillary artery, aa. Inferior dental artery, bb.

Middle meningeal artery, cc. Posterior dental artery, dd.

Infraorbital artery, ee. Descending palatine and nasal

arteries.

NX. Internal carotid, ff. Lachrymal branch of the ophthalmic

artery, gg. Network of the middle cerebral arteries.
OO. Profunda cervicis artery.

PP. Vertebral artery, hh. Its first, and k. second flexures.
QQ. Profunda cervicis vein. BB, Vertebral vein. kk. Deep

venous plexus of the neck.
SS. Occipital vein. //. Mastoid emissary vein.
TT. Lateral veins of the brain, emptying into the lateral sinus.
UU. Superior veins of the brain, emptying into the superior longi-
tudinal sinus.
W. Veins of the fissure of Sylvius.

WW. Ophthalmic vein. XX. Inferior ophthalmic vein.
III. — Motor oculi nerve. 1. Branch to the inferior oblique muscle.
(V.) — Trifacial nerve.

First division. 2. Supraorbital nerve. 3. Lachrymal nerve.
4. Its superior, and 5, inferior branches. 6. Second division
of the fifth. 7. Subcutaneous malae nerve. 8. Malar branch
severed. 9. Orbital branch going to the lachrymal gland
and often joining the inferior branch of the lachrymal nerve.
10. Infraorbital nerve. 11. Posterior dental nerve. 12.
Anterior dental nerve. 13. Trunk of the infraorbital nerve

DESCRIPTION OF THE PLATES. XXXV

passing through the infraorbilal canal. 14. Pharyngeal
nerve. 15. Third division of the fifth. 16. Buccal nerve.
17. External pterygoid nerve. 18. Anterior deep temporal
nerve. 19. Posterior deep temporal nerve. 20. Masseter
nerve. 21. Roots of the auriculo-temporal nerve, surround-
ing the middle meningeal artery. 22. Trunk of this nerve
divided. 23. Inferior dental nerve, divided near the inferior
dental foramen. 24. Mylo-hyoid nerve. 25. Its branches
to the mylo-hyoid and the anterior belly of the digastric
muscles. 26. Lingual nerve. 27. Junction of the lingual
and chorda tympani nerves. 28. Branches to the mouth.
29. Branches to the inferior maxillary ganglion. 30. Sub-
lingual branch. 31. Lingual branches. 32. Submaxillary
ganglion. 33. Its motor root coming from the chorda tympani.
34. Its sympathetic root. 35. Branches to the submaxillary
gland, and 36, to Wharton's dnct. 37. Branches joining the
lingual nerve.

VII. — Facial nerve. 38. Chorda tympani. 39. Its origin, and 40,
course between the malleus and incus. 41. Posterior au-
ricular nerve. 42. Branches to the digastric, and 43, stylo-
hyoid muscles. 44. Trunk of the facial nerve divided.

(X). — Pneumogastric nerve. 45. Superior laryngeal nerve. 4ti. In-
ternal branch. 47. External branch, going to the crico-
thyroid muscle. 48. Trunk of the vagus nerve in the neck.
4!». Inferior or recurrent laryngeal nerve. 50. (Esophageal
branches. 51. Tracheal branches. 52. Laryngeal branch.

XII. — Hypoglossal nerve. 53. Curve of the hypoglossal. 54. De-
scendens noni branch, and 55, branch to the thyro-hyoid
muscle divided. 56. Branch to the genio-hyoid muscle.
57. Branches to the hyo-glossus muscle. 58. Branches to
the genio-hyo-glossus muscle and to the muscles of the
tongue proper.

(XIII.) — First cervical nerve. 59. The internal branch of the pos-
terior division, sending filaments to the rectus capitis pos-
ticus major and minor, obliquus capitis inferior, and com-
plex US muscles. 60. The external branch of the posterior
division, sending a branch to the obliquus capitis superior
and rectus capitis lateralis muscles, and a branch over. (61),
the obliquus capitis superior to the splenitis capitis and
trachelo-mastoid muscles.

XXXVI DESCRIPTION OF THE PLATES.

(XIV.) — Second cervical nerve. 62. Anterior division. 63. Its
ascending, and 64, descending inosculating branches. 65.
Branch to the rectus capitis anticus major muscle. 66. Ex-
ternal branch of the posterior division, going to the trachelo-
mastoid and complexus muscles. 67. The internal branch of
the posterior division, which sends brauches, (68), to the com-
plexus and biventer cervicis muscles, and passes beneath
and within the complexus muscle, pierces the biventer, and
becomes the occipitalis major nerve.

(XV.) — Third cervical nerve. 69. Anterior division, from which the
greater part of the occipitalis minor, (70), auricularis magnus,
(71), and superlicialis colli, (72), come. 73. The external
branch of the posterior division, going to the scaleni
muscles, divided. 74. The internal branch of the posterior
division, which supplies branches to the complexus, biventer
cervicis, semispinalis colli and multifidus spinje muscles, and
goes beneath and within the complexus muscle, pierces the
biventer, and sends a cutaneous branch to the neck.

(XVI.) — Fourth cervical nerve. 77. Anterior division. 78. Princi-
pal root of the phrenic nerve. 79. The external branch of
the posterior division divided. 80. Internal branch of the
posterior division. 81. Muscular branches. 82. Descending
superficial cervical nerve.

(XVII. — XIX.) — The fifth, sixth, and seventh cervical nerves. 83.
The anterior divisions. 84. The external branches of the
posterior divisions divided. 85. The internal branches of
the posterior divisions.

XX. — Superior cervical ganglion. 86. Inosculating branches with
the first cervical, and 87, second cervical and hypoglossal
nerves. 88. Sympathetic nerves accompanying the external
carotid, 89, superior thyroid, 90, lingual, 91, facial, 92, occi-
pital, and 93, internal maxillary arteries. 94. Trunk of the
cervical sympathetic. 95. Middle cardiac nerve divided.

PLATE VII.

'\\T

; :-

DESCRIPTION OF THE PLATES. XXXVll

PLATE VII.

THE NERVES OF THE TEMPORAL FOSSA, SUBCUTANEOUS
MAL.E, DENTAL, DE8CENDENS NONI, EXTERNAL BRANCH
OF THE SPINAL ACCESSORY, AND THE CERVICAL PLEXUS.

This plate shows the right side of the head with the course of the
subcutaneous mala? through the malar foramina, the distribution of
the dental nerves to the superior and inferior maxillae, the relation
between the nerves of the temporal fossa and the internal maxillary
vessels, the course and inosculations of the descendens noni and ex-
ternal branch of the spinal accessory, and the position and distribu-
tion of the superficial cervical plexus.

The right side of the skull, zygomatic arch with the temporal fascia,
the ramus of the inferior maxilla, and the masseter, platysma, sterno-
cleido-mastoid and trapezius muscles are removed ; the muscles to-
gether with the vessels and nerves of the face are in part cut away,
and the malar and dental canals are opened to view.

Hence, the dura mater and middle meningeal artery, the mucous
membrane of the antrum of Highmore, the fangs of the teeth, and
the muscles, vessels, and nerves of the temporal fossa and of the neck
situated under the parts removed are seen.

A. — Skin, divided in the median line from the nose and glabella to
the neck.

B. — Frontal bone. a. Coronal suture, b. Right frontal sinus.

C. — Parietal bone. c. Lambdoid suture, d. The lower part of the
right parietal bone. e. Its anterior inferior angle, f. Men-
ingeal canal in the anterior inferior angle divided transversely.
g. Meningeal grooves.

D. — Tabular portion of the occipital bone.

E. — Temporal bone. h. Glenoid fossa, i. Eminentia articularis.
1c. Root of the zygomatic process divided.

F. — The malar bone, partly removed, to show the malar foramina.

G. — Superior maxillary bone. I. Infraorbital foramen, m. Mucous
membrane of the antrum of Highmore. n. Alveoli and
fangs of the teeth.

H. — Inferior maxillary bone. o. Angle of the inferior maxillary.

XXXV111 DESCRIPTION OF TUE PLATES.

p. Dental foramen, q. Inferior dental canal, r. Mental
foramen, s. Alveoli and fangs of the teeth.

I. — The incisor, K, canine, L, bicuspid, and M, molar teeth.

N. — Hyoid bone.

O. — Occipital portion of the occipito-frontalis muscle. P. Retrahens
aurem muscle.

Q. — Temporal muscle, t. Its superficial, and u, deep portions.

R. — The external, and S, internal pterygoid muscles.

T. — Posterior part of the buccinator muscle. IT. Mucous membrane
of the gums.

V. — Mylo-hyoid muscle.

A. — Insertion of the sterno-cleido-mastoid muscle.

E. — Splenius capitis muscle, of which a small part is removed, to
show the course of the occipital artery, z. Splenius colli
muscle. H. Upper part of the trachelo-mastoid muscle, seen
beneath the splenius capitis. &. Levator anguli scapulae
muscle. I. Upper part of the biventer cervicis muscle. K.
Scalenus medius, and A, scalenus anticus muscles. M. Ex-
ternal margin of the rectus capitis anticus major muscle.

N — The thyroid gland.

H. — The pinna, turned forward to show the distribution of the auricular
nerves.

O. — Common carotid.

n. — Superior thyroid artery, y. Superior laryngeal artery, z. Thy-
roid branches, a. Muscular branch.

p. — Lingual artery, arising by a common trunk with the facial.

2. — Facial artery. 8. Submental artery, y. Trunk of the facial,
divided transversely.

T. — External carotid, passing between the inferior maxillary bone
and temporal vein.

T. — Occipital artery. 3". Arteria princeps cervicis. s Terminal
branch.

*. — Posterior auricular artery. £. Auricular branches, n. Occipital
branch, divided transversely.

X. — Internal maxillary artery. &. Inferior dental artery, i. Menin-
geal branches of the middle meningeal artery. Its anterior
larger branch passes through a canal in the anterior infe-
rior angle of the parietal bone. x. Masseteric artery divided.
A. Posterior deep temporal artery, /w. Buccal artery.

DESCRIPTION OF THE PLATES. xxxi.X

v. Anterior deep temporal artery. £. Posterior dental artery.

o. Infraorbital artery.

Y. — Temporal artery. Tlie divided branches of the transverse facial
artery are seen amongst the internal maxillary veins (t).
it. Middle temporal artery, which divides into two branches,
ascending (p) and transverse (a-).

a. — Internal carotid.

AA. — Deep temporal plexus of veins.

Iil5. — Temporal vein composed of two trunk? which intercommuni-
cate. The superficial trunk joins the facial vein and the
deep trunk empties into the internal jugular vein.

CC. — Pterygoid plexus, -r. Internal maxillary vein. u. Deep facial
vein divided.

DD. — Facial vein, divided near the inferior maxillary bone.

EE. — Common trunk of the facial veins. <$>. Superior thyroid vein.
FF. — Internal jugular veiu. CJG. — Occipital vein.

HH. — External surface of the dura mater.

(V.) — Trifacial nerve.

iSecond division. 1. Subcutaneous make nerve. 2. Its
temporal, and 3, zygomatic branches. 4. Infraorbital nerve.
5. Posterior dental nerves, (i. Buccal branch. 7. Dental
branches. 8. Branches to the gums. 9. Inosculation of
the anterior and posterior dental nerves. 10. Middle dental
nerve. 11. Anterior dental nerve. 12. Dental branches,
and 13, branches to the gums. 14. Branch to the nose.

Third division. 15. Buccal nerve. 16. Its posterior buc-
cal branches, and 17, anterior buccal branch divided. lv.
Anterior deep temporal nerve. 19. Posterior deep temporal
nerve. 20. Masseteric nerve divided. 21. Internal, and
22, external roots of the aurieulo-temporal nerve. 23. Its
trunk. 24. Branch of the auricular joining the facial. J.".
Anterior auricular nerve divided. 26. Superficial temporal
nerve. 27. Lingual nerve. 28. Inferior dental nerve. 29.
Mylo-hyoid nerve. 30. Its muscular branches. 31. Dental
branch. 32. Posterior inferior, and 33, anterior inferior
dental nerve. 34. Branches to the mouth, 35, to the teeth,
and 36, to the gums. 37. Mental branch divided.

(VII.) — Facial nerve. 38. Posterior auricular nerve. 39. Branches
to the retrahens aarem muscle. 40. Branch to the occipital
portion of the occipitofrontal muscle. 41. Cervico-facial

xl DESCRIPTION OP THE PLATES.

division of the facial nerve. 42. Temporo-facial division of
the facial nerve, inosculating with the auriculo-temporal
nerve.

(XI.) — Spinal accessory nerve. 43. External division. 44. Branches
to the sterno-cleido-mastoid muscle. 45. Branches to the
trapezius muscle. 46. Branch inosculating with the third
cervical nerve.

(XII.) — Hypoglossal nerve. 47. Descendens noni branch. 48. De-
scendens noni branches, uniting with branches of the third
and fourth cervical nerves. 49. Ansa hypoglossi, sometimes
on the jugular vein and sometimes between it and the com-
mon carotid artery. 50. Branches to the sterno-hyoid, omo-
hyoid, and sterno-thyroid muscles. 51. Curve of the hypo-
glossal nerve. 52. Branch to the thyro-hyoid muscle. 53.
Lingual branch.

(XIII.) — Second cervical nerve. 54. Occipitalis major nerve, piercing
the biventer cervicis muscle and ascending to the occiput.
55. Descending inosculating branch of the anterior division
of the second cervical nerve.

(XV.) — Third cervical nerve. 56. Anterior division. 57. Branch to
rectus capitis anticus major muscle. 58. Branches of com-
munication with the fourth cervical, 59, the spinal accessory,
and 60, the descendens noni nerves. 61. The occipitalis
minor nerve, divided into two branches, of which the ante-
rior lesser one, (62), is cut out ; the posterior greater one,
(63), sends its filaments to the anterior region of the occiput.

64. Auricularis magnus and superficialis colli nerves divided.

65. Distribution of the auricularis magnus to the posterior
surface of the pinna. 66. Branch to the splenitis capitis et

colli muscle.

(XVI.) — Fourth cervical nerve. 67. Anterior division. 68. Branch
to the rectus capitis anticus major muscle. 69. Ascending,
and 70, descending inosculating branches. 71. Branches to
the levator anguli scapulae and splenitis colli muscles. 72.
Supraclavicular branches.

(XVII.) — Fifth cervical nerve. 73. Its anterior division.

(XVIII.) — Trunk of the sympathetic in the neck, (74).

PLATE VIII.

'P\l>

DESCRIPTION OF THE PLATES. xli

PLATE VIII.

DISTRIBUTION OF THE NERVES OF THE PACE AND NECK
UNDER THE 8UBCUTANEOUS MUSCLES OF THE FACE,
THE PLATYSMA, AND THE TRAPEZIUS.

The right side of the head, with the exit and distribution of the
first, second, and third divisions of the fifth nerve in the face, the
course and ramifications of the facial nerve under the subcutaneous
muscles of the face, and the course and distribution of the superficial
cervical nerves under the platysma and trapezius muscles are seen.

The skin and adipose tissue of the right Bide, occipito-frontalis
aponeurosis, the pericranium and external table of the skull are re-
moved by layers, the diploe' being removed to the vitreous table on
the anterior portion of the parietal bone ; the parotid gland is taken
out piece-meal, the muscles of the face are partly, and the platysma
and trapezius wholly removed.

Therefore we see, firstly, the layers of the scalp and skull : sec-
ondly, the muscles, vessels, and nerves found under the parotid
gland and subcutaneous muscles of the face and neck, then the exit
of the nerves from the cranium into the face, and finally the distri-
bution of the nerves under the subcutaneous muscli

A. — Section of the skin and adipose tissue in the median line.

B. — Aponeurosis of the occipito-frontalis muscle, likewise divided.

C. — Pericranium.

I>. — The skull. a. The outer table, b. Diploe of the frontal bone.
c. Frontal diploic veins. <l. Diploe of the posterior part of
the parietal and superior part of the occipital bones, e. Pa-
rietal diploic veins, f. Coronal suture. </. Vitreous table
of the anterior portion of the parietal bone, the inner sur-
face of which is traversed by arterial grooves.

E. — Temporal fascia, covering the temporal muscle. h. The inner,
and i, outer layers of the temporal fascia. The outer layer
is removed at the position of the middle temporal vein, so
that its course may be seen. /. Semilunar opening in the
superficial layer, through which the middle temporal vein
passes. /. Opening in the deep layer for the passage of the

xlii DESCRIPTION OF THE PLATES.

deep temporal vein. m. Malar foramina in the temporal
fascia.

F.— Eyelids.

O. — Malar bone. n. External malar foramina, o. Zygomatic arch.

H. — Superior maxillary bone. j>. Infraorbital foramen.

I. — Nasal bone.

K. — Nasal cartilages : q, superior lateral, r, lower lateral, and s,
sesamoid.

L. — Inferior maxillary bone. t. Mental foramen, u. Ramus of the
inferior maxillary bone.

M. — Hyoid bone

N. — The pinna.

O. — Origin of the zygomaticus major muscle. P. — Levator anguli
oris muscle. Q. — Buccinator muscle. R. — Depressor an-
guli oris, and S, depressor labii inferioris muscles divided
near their origins. T. — Levator labii inferioris muscle.

U. — Temporal muscle, divided transversely. V. — Masseter muscle.
v. Its deep, and w, superficial portions.

AV. — Sterno-cleido-mastoid muscle.

X. — Trapezius muscle, divided near its origin. Y. — Splenitis capitis
et colli muscle. Z. — Levator anguli scapula? muscle.
A. — Biventer cervicis muscle.

B. — Sterno-hyoid muscle, r. — Superior belly of the omo-hyoid
muscle. A. — Superior extremity of the sterno-thyroid
muscle. E. — Thyro-hyoid muscle.

z. — Insertion of the stylo-hyoid muscle. H. — Digastric muscle.
x. Its anterior belly, y. Central tendon. z. Suprahyoid
aponeurosis.

©. — Superior thyroid artery.

I. — Facial artery, a. Muscular branch. B. Mental branches, y.
Buccal branches. i. Anastomosis of a buccal branch with
the transverse facial artery, e. Inferior, and £, superior
coronary arteries. ». Anastomosis with the infraorbital
artery. &. Artery of the nasal septum. «. Lateralis nasi
artery, x. Branch anastomosing with the ophthalmic artery.

K. — Ophthalmic artery, x. Frontal artery, fx. Nasal artery, v. Su-
praorbital artery.

A. — Temporal artery, partly covered by the trunk of the temporal
vein. £. Transverse facial artery.

DESCRIPTION OF THE PLATES. xllll

M. — Internal maxillary artery, o. Buccal artery, n. Mental artery.
p. Infraorbital artery, a. Superficial perforating branch of
the anterior deep temporal artery.

N. — Posterior auricular artery.

5. — Occipital artery.

O. — Facial vein. A great portion of the trunk of this vein is removed,
so that the exit of the infraorbital nerve may be seen.
t. Frontal vein. 0. Supraorbital vein. <p. Dorsalis nasi
vein. %. Anterior extremity of the ophthalmic vein. ¥. Lat-
eralis nasi vein. <u. Deep facial vein. aa. Infralabial vein.
bb. Submental vein.

n. — Temporal vein, which is sometimes double, cc. Superficial tem-
poral vein. (Id. Middle temporal vein, which anastomoses
with the supraorbital, (ee), subcutaneous temporal, (Jj), and
deep temporal, (<jy), veins. /<//. Auricular veins. ii. Mus-
cular veins, /•/.-. Internal maxillary vein.

P. — Trunk of the external jugular vein.

Z. — Superficial cervical vein. //. Occipital vein. mm. Anastomosing
branch with the deep cervical plexus. int. Cervical
branches.

T. — Submaxillary gland.

(V.) — Trifacial nerve.

First division. 1. Frontal branches of the supraorbital nerve, at
times passing over and at times under the supraorbital vein.
Many branches issue between the frontal notch and the
superior palpebral aponeurosis, only one issues through the
frontal foramen from the orbit. 2. Superior palpebral
branch of the frontal nerve coming through a foramen of the
aponeurosis, and 3, the supratrochlear nerve coining through
another. 4. Frontal, and 5, superior palpebral brandies of
the supratrochlear nerve, b". Infratrochlear nerve. 7. Ex-
ternal branch of the nasal nerve.
Second division. 8. Subcutaneous branches of the tern poro- in alar
nerve, coming through openings in the temporal fascia.
9. Their junction with the facial nerve. 10. Zygomatic
branches of the subcutaneous malse nerve divided. 11. In-
fraorbital nerve. 12. Inferior palpebral branches. 13. Junc-
tion with the facial nerve. 14. Superior, and 15, inferior
lateral nasal branches, lb'. Internal, and 17, external supe-

xliv DESCRIPTION OF THE PLATES.

rior labial branches. 18. Buccal branches. 19. Junction
with the facial nerve.
Third division. 20. Mental nerve. 21. Mental branches. 22. In-
ternal, and 23, external inferior labial branches. 24. Buccal
branches. 25. Junction with the facial nerve. 26. The
anterior buccal branches of the buccal nerve. 27. Their
junction with the facial nerve. 28. Branches of the auriculo-
temporal, communicating with the facial nerve. 29. Super-
ficial temporal branch of the auriculo-temporal nerve.

VII. — Trunk of the facial, seen in the infraauricular fossa. 30.
Temporo-facial division of the facial nerve. 31. Temporal,
32, malar, and 33, superior buccal branches. 34. Cer-
vicofacial division of the facial nerve. 35. Inferior buccal
branches. 36. Supramaxillary branch. 37. Inframaxillary
branch. 38. Its inosculation with the superficialis colli. 39.
Intercommunication of the branches of the facial, forming
the pes anserinus. Many branches of the facial nerve are
cut through near the muscles of the face, which are re-
moved.

(XI.) — Spinal accessory nerve. 40. Its external division, going to
the trapezius muscle.

(XIV.) — Seco'nd cervical nerve. 41. Occipitalis major nerve, piercing
the biventer cervicis muscle. 42. Cervical cutaneous branch
divided. 43. Occipital branches.

(XV.) — Third cervical nerve. 44. Occipitalis minor. 45. Auricular is
magnus nerve. 46. Its facial branch divided, and 47, its
auricular branch. 48. The middle, and 49, inferior branches
of the superficialis colli. 50. Cutaneous branches divided.

51. Branches going to the levator anguli scapulae muscle.

52. Junction with the fourth cervical nerve.

(XVI.) — Fourth cervical nerve. 53. Supraclavicular branches. 54
Phrenic nerve.

PLATE IX.

DESCRIPTION OF THE PLATES. xlv

PLATE IX.

COURSE OF THE SUBCUTANEOUS CRANIAL NERVES. THE
SUPERFICIAL DISTRIBUTION OF THE FACIAL, FIRST,
SECOND, AND THIRD DIVISIONS OF THE TRIFACIAL, AND
THE SUBCUTANEOUS RAMIFICATIONS OF THE SECOND.
THIRD, AND FOURTH CERVICAL NERVES ON THE BIGHT
SIDE OF THE HEAD.

The skin of the right side of the head and neck is removed, bring-
ing the subjacent parts into view.

Therefore the parotid gland, Stenson's duct, and the subcutaneous
muscles, vessels, and nerves of the head, face, and neck may he
.seen.

A. — Skin and adipose tissue divided in the median line.

15. — Pinna, with the helix turned forward to show the retrahens
aurem muscle and posterior auricular nerve.

C. — Epicranial muscle, a. Its occipital portion, b, aponeurosis, and
c, frontal portion.

I). — Attolens aurem muscle.

E. — Retrahens aurem muscle.

F. — Orbicularis palpebrarum muscle, d. Its orbital, and e, palpe-
bral portions.

G. — Pyraniidalis nasi muscle. H. Compressor nasi muscle. I.
Levator labii superioris alaeque nasi muscle. /. Its nasal,
and (j, lahial portions.

K. — Levator labii superioris proprius, L, levator anguli oris, M,
zygomaticns major, N, zygomaticus minor, O, buccinator,
P, risorius, Q, depressor anguli oris, K, depressor labii in-
ferioi is. S, orbicularis oris, and T, levator labii inferioris
muscles.

U. — Masseter muscle, h. Its superficial, and i, deep portions.

V. — Platysma muscle. W. Sterno-cleido-mastoid muscle, k. Its
superior tendinous extremity.

X. — Trapezius, and Y, splenius capitis et colli muscles. Z. Leva-
tor anguli scapulae muscle.

A. — Parotid gland. /. Stenson's duct. in. Accessory parotid gland.

xlvi DESCRIPTION OF THE PLATES.

j? — Facial artery, n. Masseteric branch anastomosing with a branch
of the transverse facial artery. o. Buccal branch, also
anastomosing with a branch of the transverse facial artery.
p. Artery of the nasal septum g. Lateralis nasi artery.
r. Dorsalis nasi artery, s. Angular artery, t. Anastomosis
with the ophthalmic artery.

r. — Temporal artery, u. Superior, and v, inferior branches of the
transverse facial artery. w. Zygomaticoorbital artery.
x. Anastomosing branch with the transverse facial artery.
y. Anterior, and z, posterior superficial temporal arteries.
«. Anastomoses with the supraorbital, and 8> occipital
arteries.

A. Posterior auricular artery, y. Auricular branches, i. Occipital
branch.

E. Occipital artery, e. Terminal occipital branch.

Z. Ophthalmic artery. £. Supraorbital artery, passing through the
frontal muscle and then ascending upon it. n. Dorsalis nasi
artery. S. Branch anastomosing with the facial artery.

H. Facial vein. i. Frontal vein. x. Dorsalis nasi vein. x. Branch
of the supraorbital vein, perforating the orbicularis palpe-
brarum muscle and anastomosing with the facial vein.

0 Temporal vein. /t*. Superficial temporal vein. v. Its anterior,
and £, posterior branches, o. Anastomoses with the frontal,
ir, supraorbital, and f>, occipital veins, a-. Middle temporal
vein. t. The trunk of the temporal vein is here double, but
usually only one trunk is found.

I. External jugular vein, covered by the platysma muscle.

K. Superficial cervical vein. v. Occipital vein. <f>. Anastomosing
branch with the deep cervical plexus. £. Cervical branches.

(V.) — Trifacial nerve.

First division. 1. Frontal branches of the frontal nerve, passing

through the fibres of the frontal muscle, then going to the vertex

subcutaneously. 2. Frontal branches of the supratrochlear nerve.
Second division. 3. Inferior palpebral branch of the infraorbital

nerve. 4. Laterales nasi branches of the infraorbital nerve.

Third division. 5. Anterior auricular branch, and 6, temporal

branches of the auriculotemporal nerve. 7. The anterior buccal

branches of the buccal nerve. 8. Branches of the buccal joining the

facial nerve.

DESCRIPTION OF THE PLATES. xlvii

(VII.) — Facial nerve. 9. Posterior auricular nerve. 10. Temporal,
11, malar, 12, superior buccal, and 13, inferior buccal
branches 14. Supramaxillary, and 15, inframaxillary
branches. 16. Branch piercing the platysma muscle. 17.
Inosculation with the middle Buperficialis colli nerve. 18.
Intercommunicating branches of the facial nerve

(XL) — Spinal accessory nerve. 19 Its external division, going to the
trapezius muscle.

(XIV. — Second cervical nerve. 20. Occipitalis major nerve, piercing
the bi venter cervicis and part of the trapezius muscles,
''ranches of this nerve accompany the occipital artery and
vein to the vertex.

(XV.) — Third cervical nerve. 21. Occipitalis minor, one branch of
which pierces the border of the trapezius muscle and ascends
to the anterior part of the occiput ; another branch passes
amongst the branches of the superficial cervical vein, joins
the occipitalis major nerve and goes to the vertex. 22. An-
terior cervical cutaneous branches. 23. Auricularis magnus
nerve. 24. Its auricular branches. 25. Facial branch of
the auricularis magnus. 26. Facial cutaneous branches
divided. 27. Cutaneous branches piercing the platysma
muscle. 28. Superficialis colli nerves piercing the platysma
muscle. 29. Branches to the levator anguli scapuhe muscle.

(XVI.) — Fourth cervical nerve. 30. Its anterior division.

ESSENTIALS OF HUMAN PHYSIOLOGY.

What is physiology?

Physiology is the study of vital phenomena which are always
present in living things he they animal or vegetable. As a con-
sequence of this we divide physiology into two subdivisions, known
as animal physiology and vegetable physiology, but it should be
remembered that the line of demarcation between animals and
vegetables in the lower forms of life is very ill-defined. The word
physiology is derived from the Greek word avoir, nature, and
a discourse, and in its original meaning was applied to the study
of natural history in general. Physiology is really synonymous
with the term biology, since it is necessary for the study of either
one that vital properties be present in the thing studied. The term
biology, however, has a wider scope with certain persons, as under
some circumstances it is divided up into morphology, which treats
of the forms and structure of living bodies, while physiology at-
tempts to explain the modes of activity exhibited by them during
their lifetime. In other words, morphology stands in the same
position in reference to physiology as does anatomy. The term
vital phenomena is applied to the changes which constantly go on
in all living bodies, the primary causes of which are not at all
understood ; in other words, while we note the ultimate object of
each function we can give no cause for the setting in motion of
that function.

What is the chemical basis of the body?

Of the sixty-nine elements known to chemists, a very small
number, comparatively speaking, are found in any quantity in
living animal matter, although traces of them are frequently
present. Oxygen, carbon, hydrogen, and nitrogen are present in
very large proportions in every tissue, and together make up about
97 per cent, of the whole body, while the sulphur, phosphorus,
chlorine, fluorine, silica, potassium, sodium, magnesium, calcium,

2

18 ESSENTIALS OF HUMAN PHYSIOLOGY.

and iron are indispensable to the economy, but are widely distrib-
uted and occur in much smaller quantities. Since to investigate
the chemical composition of a tissue must require analysis, the
composition of the tissues during life is, strictly speaking, un-
known, since by the very analysis death is produced. An im-
portant point to be remembered is that all animal bodies, be they
simple or complex, are made up of protoplasm more or less differ-
entiated according to the function which it is to fulfil.

What two great groups of substances make up the body ?

Physiological chemistry teaches us that we have in the body two
sets or groups of substances known as nitrogenous and non-nitro-
genous. The nitrogenous perform the most important functions,
and, indeed, form all the active portions of the organism. As the
simplest representative of these nitrogenous bodies may be men-
tioned protoplasm itself. Derived from this and entering into the
formation of it are albumens, serum-albumens, and, thirdly, by
the outcome of still further differentiation we have albuminoids,
chiefly represented by gelatine. Last of all are those products
which, though nitrogenous, differ from the others in that they are
intermediate or effete products of tissue manufacture or waste, as,
for example, urea, uric acid, kreatin, and kreatinin. The non-
nitrogenous substances consist chiefly of the carbohydrates, which
contain hydrogen and oxygen in the proportion found in water, as,
for example, starch and sugar. Then we have substances contain-
ing oxygen in less proportion than the above, namely, fats. Salts
occur all through the tissue, as does also water.

PROTEIDS.

All compounds included in the group of proteids contain carbon,
hydrogen, nitrogen, oxygen, and sulphur.
They are amorphous, with variable solubility in water and acids,
usually soluble in alkalies, almost insoluble in alcohol and ether.
They are precipitated from their solutions by excess of strong
mineral acids, by acetic or hydrochloric acid, potassium ferro-
cyanide, and the basic acetate of lead, mercury bichloride, tannin,
and potassium carbonate in powder.

CLASSIFICATION OF PROTEIDS.

19

Soluble in
pure water

The following table, taken from Gaingee's Physiological Chem-
istry, is of great importance, and gives the points to be remembered
most tersely. This will be, of necessity, frequently referred to
later on.

Class 1.— Albumens are proteid liodies which are soluble in water, aud
which are not precipitated by alkaline carbonates, by sodium chlo-
ride, or by very diluto acids. It" dried at a temperature below 40°
C. they become transparent and yellow, break with vitreous frac-
ture, and are soluble in water. Coagulation occurs between 65°
ami 7:: 0.

1. Serum-albumen, not precipitated from its rotations by the
addition of ether.

2. Egg-albumen, precipitated from its solution by agitation with
ether.

I i ass 2. -Peptones, proteid bodies exceedingly soluble in water. Solu-
tions are not coagulated by heat when precipitated by sodium chlo-
ride, nor by acids or alkalies ; precipitated by a large excess of
absolute alkali and by tannic acid in the presence of much caustii
potash or soda. A trace of a solution of copper sulphate producesa
[ beautiful rose color.

Class 3.—Gl<,buli)is, proteid substances which are insoluble in pure
water but soluble in dilute solutions of NaCl. These solutions are
coagulated by heat They are soluble in dilute hydrochloric acid,
being converted by alkalies into alkali-albumen.

1. Vitellin, not precipitated from its solution when saturated

with common salt.
-'. Myosin, precipitated from its solution by weak common
salt. When saturated with sodium chloride it coagulates
at 55° to 00° C. Solutions in common salt are not coagu-
lated by a solution of fibrin-ferment.
.?. Fibrinogen, soluble in weak solutions of NaCl, precipitated
from them completely on the addition of NaCl when this
amounts to twelve or sixteen percent. Solutions coagulate
on the addition of fibrin-ferment and at the temperature of
60° C.
4. Paraglobulin, soluble in weak solutions of NaCl, and pre-
cipitated from weak alkalino solutions by the addition of a
small quantity of NaCl. A further addition of this body
redissolves the precipitate, which is again precipitated,
although not so completely as before. When the amount
of NaCl in solution exceeds twenty percent, paraglobulin
is completely precipitated when the solution is saturated
with ammonium sulphate. Its solutions are not precipitated
by the addition of the fibrin ferment It coagulates at
different temperatures according to the amount of salts
present and the mode of heating, but generally between
68° and 80° C.

Insoluble in
pure water,
but soluble
in weak
solutions of
common salt

20 ESSENTIALS OF HUMAN PHYSIOLOGY.

Class 4. — Derived albumens, proteid bodies insoluble in pure water aud in solution? of
NaCl, but readily soluble in dilute HC1 and h. dilute alkaline solutions. Solutions
are not coagulated by neat.

1. Acid-albumens, obtained by the action of dilute acids, especially HC1, on

solutions of proteids, and by action of strong acids upon solid proteids.
They occur as first products in the action of gastric juice. NaCl added to
saturation precipitates them.

2. ('<) Alkali-albumens, obtained by the action of dilute alkalies upon the pro-

teids, possessing the properties of acid-albumen with the exception that in
the presence of an alkaline phosphate the solutions are not precipitated by
neutralization. They occur as the first products of pancreatic digestion
(6) Casein, the chief proteid constituent of milk, has the same properties as
alkali-albumen, but when treated with a strong solution of caustic potash
potassium sulphide is formed ; with alkali-albumen it is not formed.

Class 5. — Fibrin is insoluble in water and in weak solutions of NaCl, and becomes
swelled up in cold hydrochloric acid of one-tenth per cent, solution, but does not
dissolve unless pepsin is added and heat is applied.

1. What tests have we for proteids?

The nitric acid test, which consists in heating the liquid and
adding nitric acid until the reaction is strongly acid, when a pre-
cipitate occurs. Remember, that this is not an infallible test for all
proteids, as, for esample, the peptones, which will not respond to it.

2. What is the xantho-proteic reaction?

Heat with concentrated nitric acid, when, if a proteid be present,
a yellow tint appears, which becomes reddish-orange on the
addition of alkalies.

3. What is Millon's reagent?

It is made by dissolving in the cold one part of mercury in its
weight of concentrated nitric acid, the solution being completed
by applying gentle warmth ; two volumes of distilled water are
then added, and the fluid decanted. This test gives a red color
with liquids containing proteids, which is more marked when they
are heated to 60° C. or 70° C.

CARBO-HYDRATES.

These include the starches and sugars.

What test have we for starch ?

March, when added to free iodine, strikes a blue color which dis-
appears on the application of heat, but returns if the liquid be

THE BLOOD. 21

suddenly cooled. If heated to the temperature of 210° C. starch is
converted into dextrin, and, as we shall learn later, the digestive
fluids change starch into glucose or grape sugar.

Sugars are substances having a more or less sweet taste, usually
soluble in water, destroyed by strong H2S04, which abstracts water
from these compounds, and leaves only the carbon. The most
important of this group are glucose, lactose, saccharose, and gly-
cogen. < )n fermentation they yield C0.2 and alcohol.

What test have we for sugars ?

Trammer's (est, which depends upon the fact that sugar in an
alkaline solution acts as a reducing agent. To the saccharine
fluid about one-fourth of its bulk of caustic potash or soda is added,
and a dilute solution of copper sulphate. A slight clouding occurs
which disappears on shaking, but boiling strikes a brick-red color.

Fats are widely distributed in plants and in animals. They
contain very little oxygen, and are soluble in ether, benzole, chloro-
form, and in boiling alcohol. When fats are boiled with solutions
of the alkaline hydrates or carbonates they undergo saponification,
and are decomposed into glycerin and fatty acids. The latter
immediately combine with the alkali and form soap.

Fats also undergo emulsification, in which process they are
broken up into a condition of extremely fine subdivision.

THE BLOOD.

What is the function of the blood ?

In all animals, except those which form the lowest class, a liquid
medium corresponding, in function at least, to the blood of man,
circulates. It serves in the distribution of nutritious materials to
the various parts of the system and, equally important, it collects
those substances which have resulted from the changes which are
constantly going on in the tissues and bears them to those organs
whose function it is to discharge them from the body. Quite aa
important is the constant intercourse which it keeps up between
the tissues and the air, supplying them with oxygen.

22 ESSENTIALS OF HUMAN PHYSIOLOGY.

What is the color of the blood in the different portions of
the circulatory system ?
The color of the blood as it occurs in the systemic arteries is of
a bright scarlet-red, while in the corresponding veins it is of a
dark bluish color. In the pulmonary artery it is dark blue, in
the pulmonary veins scarlet.

What is the cause of this variation ?

The cause of this variation is due to the oxygen of the air, which,
entering into a chemical combination with the haemoglobin of the
red blood corpuscles, produces oxyhemoglobin, which gives up
some of its oxygen to the tissues of the body as it passes through
the capillaries, and returns in the veins partly decomposed into re-
duced haemoglobin, which gives to the venous blood its dark hue.

Is the entire amount of oxyhaemoglobin reduced in venous
blood ?

No. The reduction of haemoglobin amounts to only about five
per cent.

Are the red blood corpuscles red or yellow ?

They are red, for their coloring matter, haemoglobin, is red when
isolated and crystallized.

The color of the red corpuscles when seen singly is yellowish-red.

The difference in color between those seen en masse and those
seen singly is due to the refraction of light.

What is the reaction of the blood ?

The reaction is alkaline, owing to the presence of sodium carbo-
nate and disodic phosphate, Na^HPO^

Does it always retain its alkalinity ?

Always during life, but after blood is shed its alkalinity rapidlj
diminishes, and the greater the alkalinity of the blood is, the more
rapidly this change occurs. Finally, the reaction becomes
strongly acid, this change coming at about the time of coagula-
tion.

What is the odor of the blood ?

The odor which the blood possesses differs in the various
animals, and in some animals is very characteristic. This odor
depends upon the presence of volatile fatty acids.

THE BLOOD. 23

What is the taste ?

It is saline in taste, which is dependent upon the salts contained
in it.

What is the specific gravity of the blood ?

The specific gravity is 1055, the extreme limits being from
1045 to 1075. The specific gravity of the blood corpuscles alone
is 1105, that of the plasma 1027. As a consequence of this, blood
corpuscles tend to sink to the bottom of the receptacle into which
the blood is drawn.

What is the temperature of the blood ?

It varies from 98° F. at the surface of the body to 107° in the
hepatic vein.

Of what does the blood consist ?

Blood, when flowing in a normal condition through the blood-
vessels, consists of an almost colorless fluid, the plasma, in which
are suspended small solid bodies, known as red and white blood
corpuscles and blood-plates. The liquid portion of the blood (the
blood plasma or liquor sanguinis) is of a pale straw color when
free from blood corpuscles or other coloring matter, and is the
liquid which keeps the corpuscles afloat. The blood plasma is not
identical with the serum of the blood, since radical changes take
place in its composition during coagulation, and the serum results
after the clot is formed. Serum will not of itself form a clot,
plasma will ; in other words, one of the differences between liquor
sanguinis, or plasma, and serum, is that the first contains fibrino-
gen, while the second does not.

Is there any variation in the character of the blood in
different parts of the circulatory system ?
The arterial blood contains more oxygen and less C02, and is
more coagulable. The blood of the portal vein varies with the
stages of digestion, during which time it is richer in water, albu-
minous matters, and sugars, with a diminished number of cor-
puscles. In the hepatic vein the sugar is increased, but the
albumin and fibrinogen diminished.

24 ESSENTIALS OF HUMAN PHYSIOLOGY.

What are the two varieties of blood corpuscles ?

Red and white.

What others have we?

Very small ones, known as microcytes, and the so-called blood-
plates.

What is the function of these microcytes ?

Most physiologists believe them to be young red blood corpuscles,
others that they are worn-out red blood corpuscles.

What is the function of the blood-plates ?

It is not known, but they are found in large numbers in thrombi,
and possibly take part in the process of coagulation by helping to
form fibrin-ferment. They do not become red corpuscles.

Describe the white corpuscles.

They are small protoplasmic cells, differing in no way from the
pale round cells found in most portions of the body, and occur in
large quantities in the lymph. For this reason they are sometimes
called lymphoid cells or leucocytes. They possess a finely granular
structure and nuclei, and these nuclei may often be recognized
near the centre of the cell. The nuclei may be made more marked
by the action of certain reagents, notably acetic acid. They pos-
sess an amoeboid movement, and so are enabled to migrate not
only through the bloodvessel wall, but also through the tissues.
They are somewhat larger than the red disks, and do not possess
a cell wall.

What do you mean by diapedesis ?

The passage of the white blood corpuscles through the blood-
vessel wall. The white corpuscles constantly pass through
normally, but in very large numbers in inflammation. The red
only under morbid conditions, as in injury or inflammation.

What are the relative positions of the red and white cor-
puscles in the blood stream of the smaller arterioles
and capillaries ?
The red move along rapidly in the centre, while the white slowly

roll along the walls. If inflammation occurs, they stop and block

THE BLOOD. '!'>

the vessel. The layer of blood in which the white corpuscles lie
is called the " still layer."

Where are the white corpuscles formed ?
According to the best physiologists, in the lymphatic glands and

the spleen, and very similar cells develop in the connective tissues
through multiplication by division.

What are their functions ?

1. To destroy pathogenic bacteria (the phagocytosis theory of
Metschnikoff).

2. To take part in the process of blood-coagulation by forming
fibrin-ferment (thrombin).

3. To aid by their disintegration the normal composition of the
blood-plasma as to proteids.

Describe the red blood corpuscles.

The red blood corpuscles give the red color to the blood of all
vertebrated animals except the amphioxus, but arc not found in
the blood of invertebrates. They differ in their shape in almost
all animals, in the mammalia they are biconcave disks. Their
size differs in each class of animals, but the size of the animal has
no relation to the size of the corpuscle, for in the frog all the
corpuscular elements are of great size. They are soft and elastic,
and bend and alter their shape when necessary to pass through a
narrow bloodvessel, but return immediately to their normal shape
as soon as the pressure is removed. If blood be withdrawn from
the body, even for a few moments, and then returned to the circu-
lation, death of the corpuscles takes place, and in a short time
evidences of their destruction may be noticed by the presence of
haemoglobin in the urine.

What is one of the peculiarities of the red blood corpuscles
outside the body ?
They form themselves into rouleaux, which resemble very
closely the appearance of a large number of coins placed side by
side. This peculiarity is due rather to a physical law than to any
action of the corpuscles themselves, since it has been found that
small disks of cork will do very much the same thing when placid
in water.

26 ESSENTIALS OF HUMAN PHYSIOLOGY.

Have the red blood corpuscles any nuclei ?

Not in adult life, but owing to their biconcave shape the refrac-
tion is such that under the microscope a dark spot is apparently
situated near their centre. In the young embryo nucleated red
corpuscles are found.

Are the red blood corpuscles few, or are they exceedingly
great in number ?

Their quantity is enormous ; a cubic millimetre contains be-
tween four and five millions. Approximate mathematical estimates
show that the red blood corpuscles of an adult present an aggre-
gate surface of about three thousand square yards, while the
surface they represent for the absorption of oxygen in the lungs
in one second is about eighty square yards.

How are they formed ?

In adult life from the erythroblasts of the red marrow of the
bones ; in the embryo they are also formed in the liver and spleen.

What is the end of the life history of the red blood cor-
puscles ?

Many physiologists regard the liver as one of the chief places
where the disintegration of the red blood corpuscles takes place,
and this is supported by the facts that the bile-pigments are formed
from haemoglobin and that the blood of the hepatic vein contains
fewer red blood corpuscles than the blood of the portal vein. The
spleen is also regarded as one of the organs in which the red blood
corpuscle is disintegrated. It is probable that they are destroyed
largely while in the general circulation, and do not require any
special organ for their destruction.

What are the functions of the red corpuscles, and their rela-
tive number to the white corpuscles ?

The function of the red blood corpuscles is entirely different
from that of the white blood corpuscles. The red blood corpuscle
contains in its stroma a large amount of haemoglobin which, when
exposed to the air in the lung, takes up oxygen, thereby forming
the chemical compound known as oxy-hsemoglobin. By these
means the tissues, even in the most distantly removed parts of the

T HE BLOOD. 27

body from the lung, receive their oxygen, the exchange of oxygen
from the corpuscles to the tissues taking place in the capillaries.
By this means, oxidation, with the resulting tissue break-down,
and the development of beat, takes place in every portion of the
body.

The relative number of the white blood corpuscles to the red
has been much discussed, some observers giving it as 1 t<» 300,
while others state that it is 1 to 700. The proportion varies 80
much in different parts of the circulation that no estimate is of
any great value.

Do changes ever occur in the relative number of red and
white corpuscles in health?
Very frequently, since many circumstances arising in every-
day life may produce great changes in this respect. The varia-
tion may be all the way from 1 in 50 to 1 in 1200. Pregnancy
decreases the proportion ; meals also have a very powerful effect
on their relative numbers. Certain diseases also alter the pro-
portion greatly.

What is haemoglobin ?

It is the substance which gives the red color to the corpuscles,
and carries by their aid the oxygen to the tissues.

What is haematin?

A result of the decomposition of haemoglobin by acids or alka-
lies in the presence of oxygen.

Haemin is a compound of haematin and HC1.

Haematoidin is a crystal lizable substance found in old blood-
clots and comes from haemoglobin. It is identical with the bile-
pigment, bilirubin.

What are the gases of the blood ?

Chiefly oxygen, carbonic acid, and nitrogen. The oxygen exists,
as before stated, in chemical combination with the haemoglobin,
and is also in small amounts simply absorbed by the blood plasma.

Carbonic acid occurs in less amount in arterial blood than in
venous blood.

Nitrogen exists in the blood in very small amount, and appears
to be simply absorbed.

28 ESSENTIALS OF HUMAN PHYSIOLOGY.

From 100 volumes of blood may be obtained —

0. C02. N.

Of arterial blood (from) 20 vols . 40 vols. . . 1 to 2 vols.

a large artery), )

Of venous blood (from ] 8_^ « 45 « 1 to 2 "

rigbt side of heart), i

Does C02 unite with the haemoglobin?

No. It is held in solution chiefly by the plasma, and in very
small amount in the red blood corpuscles.

What is the quantity of the blood ?

The quantity of blood in a human male adult is equal to one-
thirteenth part of the body weight.

Coagulation of Blood.

Blood, on being withdrawn from a vessel, is perfectly fluid, but
rapidly becomes thick, and then forms a clot resembling a solid
gelatinous mass.

What is this clotting due to ?

The formation of fibrin, in part at least, from fibrinogen.

Does fibrin exist already formed in the blood ?

No.

How is it produced ?

There is no perfectly satisfactory theory of coagulation. The
most generally accepted one is that of Hammarsten, that the reac-
tion between fibrinogen and fibrin-ferment (thrombin) produces
fibrin.

It is also necessary that calcium salts be present, for without
them fibrin cannot be formed from fibrinogen. Fibrin-ferment
does not exist in the blood until after it is shed ; then the disinte-
gration of the white blood corpuscles occurs and the ferment is
formed.

How is the clot made up ?

The fibrin forms in fibrils, which entangle the blood corpuscles
as in a spider's web, and thereby form a complete blood-clot.

COAGULATION OF BLOOD. 29

The blood in the body is made up as follows :

Blood
I

Plasma Oorpnsclee (red and white)

I I

Water Fibrin-ferment

I

Salts

I

Serum-albumin

Paraglnl.iiliii

Fibrinogen.

Blood when it has undergone coagulation is as follows:

Blood
I

r j

Plasma Corpuscles, red and whits

I

I
Clot

I
Containing tibrin, corpuscles, and serum.

What chp'^ges take place after the clot is formed?

The clot leaves the sides of the vessel, and on its surface there
appear small transparent drops of yellowish liquid known as serum.
These drops running together form a layer of yellowish fluid.

In what way is the serum expelled from the clot?

The fine fibrils of fihrin ramifying all through the clot contract,
and squeeze out the serum. These fibrils also entangle the
corpuscles.

How long does this contraction and displacement of the
serum last?
From twenty-four to thirty-six hours.

How is blood defibrinated?

By beating it with twigs or a glass rod. The fibrin adh< n
sticky masses to the rod-, and the remaining fluid will not clot.
The corpuscles are left, most of them in the serum.

30 ESSENTIALS OF HUMAN PHYSIOLOGY.

What conditions hinder or delay coagulation?

The addition of small quantities of alkalies or of concentrated
solutions of neutral salts of alkalies, notably magnesic sulphate;
the addition of egg-albumin, syrup, glycerine, and much water;
and by covering the blood with oil, or by cold at freezing point.

What hastens coagulation ?

Coagulation is accelerated by contact with any foreign body, by
heating from 39° to 55° C, and by constant agitation.

What do you mean by the buffy coat?

In blood which is drawn from a body during inflammation the
fibrin coagulates slowly, and the corpuscles subside to the bottom
of the vessel, so that the upper stratum of the clot is not red but
only yellowish, containing scarcely any red blood corpuscles.
This occurs physiologically in horses' blood.

What prevents coagulation of the blood in the bloodvessels?

This is not positively known ; some relationship exists between
living tissues and the blood.

Under what circumstances does clotting in the bloodvessels
occur ?

As soon as the endothelial layer of the bloodvessels is in any
way injured.

How long after death does the blood coagulate in the
body?

From ten to twenty-four hours.

Do pathological changes ever take place in the blood ?

Yes. Plethora is an increase in the quantity and quality of the
blood, the red corpuscular elements being greatly increased in
number

Anosmia is a decrease in the corpuscular elements of the blood,
without necessarily any increase in the liquids.

Leucocythcemia or leukaemia is a term applied to a condition in
which, together with other changes, the white blood corpuscles are
very much increased in number, from 10,000 to 1,000,000 in a cubic
millimetre of blood. In some cases the white corpuscles are as
numerous as the red.

TIIE HEART. 31

Uni'iiiin cannot be considered a disease of the blood, but simply
an accumulation of urea in that fluid, owing to kidney disorders.

THE HEART.

What is the simplest form of heart ?

The early embryonic heart, which is merely a tubular heart
with one cavity and an outer circular and inner longitudinal
layer of fibres.

Does the muscular fibre of this tubular heart afford walls
to both the auricle and ventricle after the septum is
formed ?

Yes, but the muscular fibres of the auricle do not change to any
extent, while the ventricular fibres become much altered.

What separates the auricular fibres at this time from the
ventricular fibres ?
Fibrocartilaginous rings at the opening in the septum.

What is the function of the heart ?
To propel blood through the body.

How many cavities has it ?
Four.

What is the weight of the adult male heart ?
Nine ounces.

What is the weight of the adult left ventricle as compared
to the right?
About twice as heavy.

What is the difference between the right and left side of
the heart ?

The right side of the heart takes the venous blood from the
vena cava? and pumps it through the lungs to the left side of the
heart. This circulation is much more limited, of course, than that
produced by the left side, and is known as the pulmonic circulation.

32 ESSENTIALS OF HUMAN PHYSIOLOGY.

The left side of the heart receives the arterialized blood from the
lung and drives it into the general arteries. This is known as the
systemic circulation.

Which is the strongest, the right or left side of the heart ?

The left side is not only much stronger, but its walls are much
thicker on account of the greater amount of work which it is
forced to perform.

What is the difference between the contraction of the
auricles and the contraction of the ventricles ?

The contraction of the ventricles takes place synchronously
from all sides, so that the pressure within is equal in any direc-
tion. The auricles contract peristaltically from the opening of
the supplying vessel toward the auriculo-ventricular orifice.

Which have the thickest walls, the ventricles or the auricles ?

The ventricles, owing to the greater force which they are re-
quired to put out.

What is the function of the auricles ?

To act as a reservoir for the blood while the ventricles are
contracting, and force the blood through the auriculo-ventricular
openings, and so supply the ventricles.

Has the heart any suction power enabling it to aid the
circulation not only by pushing but by sucking ?
According to the latest researches it has not.1

What is the endocardium ?

The membrane lining the heart.

Is it limited to this viscus or not ?

It is continuous with the endothelial lining of the bloodvessels.

Has the endocardium bloodvessels
No, it has not.

1 The muscular arrangement of the heart is probably already known to the student ;
if not, he must turn to his anatomical text-books.

THE HEART. 33

What are the valves of the heart ?

They are fibrous flaps arranged in one of two ways, which open
and shut the orifices which they guard. The edges of the auriculo-
ventricular valves are attached by what are known as chordae
tendineae to the walls of the ventricles.

In what way are the valves attached to the heart ?

They are fixed to the fibrous rings, made up of yellow elastic
tissue and fibrous tissue which surround the openings.

Do the valves have any muscular fibres in them ?

According to Reid and Gussenbauer, the auriculo-ventricular
valves do; the fibres come from the auricles.

Have the valves bloodvessels ?

None near the edges. Only as far as the muscular fibres run.

What is the function of the valves ?

To prevent the regurgitation of blood from a heart cavity, or
bloodvessel, back into the area from which it has been propelled.

What two sets of valves have we ?
The auriculo-ventricular and semilunar.

Where are they situated ?

The semilunars guard the opening of the aorta and pulmonary
artery.

At the right auriculo-ventricular orifice we have the tricuspid
valve, at the left auriculo-ventricular we have the mitral or
bicuspid valve.

How many cusps make up the semilunars ?
Three at each opening.

Are there any valves at the opening1 of the cavse into the
right auricle ?
No.

Why are they not needed ?

Because the peristaltic action of the auricle prevents a tendency
to regurgitation, except in rare conditions. For the same reason

3

34: ESSENTIALS OF HUMAN PHYSIOLOGY.

we have no valve at the opening of the pulmonary vein into the
left auricle.

What are the chordae tendineae ?

The chordae tendineae are small bands running from the mus-
cular fibres of the heart wall to the edges of the valves.

What is the function of the chordae tendineae ?

To prevent the everting of the auriculo-ventricular valves into
the auricles by a sudden pressure of blood during ventricular
systole.

In what way is the heart nourished ?

By means of its coronary arteries, which are peculiar in that
they do not anastomose.

Where do these arteries arise ?

From the aorta near the sinus of Valsalva.

What is the condition of the openings of these arteries
during the period of systole ?
They are closed by the aortic valves.

Are the veins of the heart called coronary veins ?
No. They are called cardiac veins.

What other cause produces an onward flow of the blood
through the coronary arteries than the vis a tergo
from the systolic driving out of blood into the
aorta ?

The lateral pressure exercised on the vessels by tha surrounding
heart muscle.

What effect has ligation of one or both coronary arteries?

The heart in two minutes changes its rhythmical movements
into twitchings and soon ceases all movement.

What is this change due to ?

Both to failure of nutrition and to failure in the removal of
effete matters from the heart by the blood, as a consequence of
which the heart is poisoned by the poisons generated by itself.

THE HEART. 35

What are the columnse carneae ?

They are small ridges of muscular tissue lying on the ventricular
wall.

What are the musculi papillares ?

They are small teat-like muscular projections arising from the
inner portion of the ventricular wall, to which the chorche tendinese
are generally attached.

What is their function ?

As the ventricle contracts and the heart shortens they pull the
chordae tendineae tense and take up the slack, as it were.

In what way does the blood circulate through the heart?

Entering the right auricle from the cavse, it passes through the
right auriculo-ventricular opening into the right ventricle, then
through the pulmonary artery into the lungs, from the lungs
through the pulmonary veins to the left auricle, and through the
left auriculo-ventricular orifice to the left ventricle, from the
ventricle through the aorta, and so on through the arterial system.

How much blood is sent out of the left ventricle ordinarily
in the adult at one contraction ?
About four to six ounces.

How much force does the heart put out at each systole ?

Enough to lift three foot-pounds.1 Of this the left ventricle
does two and a quarter pounds. In twenty-four hours the heart
puts out enough force to lift one hundred and twenty-four foot-
tons, or enough to lift one ton one hundred and twenty-four feet.

What are the movements of the heart ?

The chief movements are those of contraction, or systole, and
expansion, or diastole.

The two auricles contract synchronously, thereby filling the
ventricles, then the ventricles contract together, and then follows
diastole. Following ventricular diastole there is & pause.

1 A foot-pound represents the force required to lift one pound one foot.

36 ESSENTIALS OF HUMAN PHYSIOLOGY.

Systole, diastole, and the pause, therefore, make up one cardiac
revolution or cycle.

Does the heart change its position during contraction or
expansion ?
Yes, somewhat ; for, with contraction, the base of the heart de-
scends, the base of the ventricle goes toward the left but the whole
heart rotates a little to the right, and the apex is tilted a little for-
ward. The vertical movement of the apex amounts to nothing.

At what time does the impulse of the heart take place
against the chest ?
During systole.

What is the object of the pericardium ?

It acts as a protecting membrane surrounding the heart. The
visceral layer covers the heart and is in turn covered by a reflexion
of the membrane which forms the parietal layer. These two
surfaces secrete a sufficient quantity of liquid to lubricate their
surfaces as they move on one another.

When the heart is slowed or quickened, is the change in
speed due to a change in systole or diastole, or
both?

Systole remains unaltered, diastole is prolonged when slowing
occurs, shortened when quickening occurs.

How many heart sounds have we?
Two; the long, dull "lub," and the short, sharp "dup."

What are the sounds of the heart due to ?

The first sound is due to the vibration of the auriculo-ven-
tricular valves made tense by the systolic force of the ventricles,
and also the sudden contraction of the muscular fibres of the heart
walls. The striking of the apex against the chest wall does not
even help the first sound, since it can be heard after the wall is

THE HEART. 37

removed. The second sound is produced by the closure of the
aortic valves.

At what rate does the heart beat ?

Before birth, per minute, the beats are 140-150.

During first year, per minute, the beats are 125-135.

1 Miring third year, per minute, the beats are 95-100.

During eighth, ninth, and tenth to fourteenth year, 85-90.

In the adult, about 72.

In very old age, or decrepitude, the pulse once more becomes fast.

In which sex is the pulse most rapid ?
In females.

What effect has posture on the pulse ?

The erect posture causes a more rapid pulse than the recum-
bent.

What other conditions influence its rate ?

Respiratory changes, drinking water in small repeated swallows,
and many similar conditions.

What is the intrinsic nervous mechanism of the heart ?

The intrinsic nervous mechanism of the heart consists in three
centres, which have been proved to exist in the heart of the frog,
and are generally received as the centres for the mammalian heart.
The three centres are:

1. The motor ganglion, or that of Remak.

2. The accelerator, or second motor ganglion, or that of Bidder.

3. The inhibitory ganglion, or that of Ludwig.
Fig. 1. will serve to illustrate the matter :

The motor ganglion (a) sends out through its radiating fibres
impulses which drive the heart.

The accelerator motor ganglion {b), when it acts, quickens the
irradiation of these impulse-.

The inhibitory ganglion (c) prevents the heart from beating too
fast.

38 ESSENTIALS OF HUMAN PHYSIOLOGY.

Fig. 1.

a. The motor centre, that of Remak. 6. The accelerator motor centre, that of Bidder
c. The inhibitory centre, that of Ludwig. <l. The accelerator nerves, e. The pneumo-
gastric or inhibitory nerves. The arrows represent direction in which impulses travel

What keeps up the contraction of the muscle ?

The constant circulation of the blood over the endothelium,
thereby stimulating and sending reflex impulses to the motor
ganglion.

What are the extrinsic cardiac nerves ?

The accelerators and the pneumogastric or inhibitory nerves,
which arise in the base of the brain and are governed by centres
there.

What is their function ?
They govern the ganglia in the heart muscle.

Are the pneumogastric nerves and the accelerators,
strictly speaking, antagonists ?
They are not, for the accelerators do not act all the time, while
the pneumogastrics do, and the vagi can always overcome readily
any accelerator influence.

What effect on the heart has stimulation of the pneumo-
gastrics
It slows the pulse and produces large and full diastole.

THE HEART. 39

What effect has section of the vagus ?
It produces an exceedingly rapid pulse.

What effect has stimulation of the accelerators ?
Stimulation of the accelerators makes a very rapid pulse.

What is the depressor nerve, and what is its function ?

The depressor nerve is given off from the superior laryngeal
nerve and the trunk of the vagus in the rabbit, and passes into the
cardiac plexus. It conducts impulses from the heart to the vaso-
motor centre, and lowers the activity of that centre, thereby relax-
ing the bloodvessels somewhat. In this way the heart when over-
worked, owing to the increased resistance of high blood-pressure
(vasomotor spasm), can be relieved as soon as is necessary.

What is the function of the so-called pressor fibres of the
laryngeal nerves ?
They stimulate the vasomotor centre, causing a rise of blood-
pressure. They are, therefore, the direct opponents of the depres-
sor fibres.

What are the functions of the bloodvessels ?

The bloodvessels carry blood to and from the various tissues and
organs. They are divided up into three divisions, known as: 1,

Fig 2.

Capillary network of fat tissue. (Klein.)

arteries and arterioles; 2, capillaries; 3, veins. Of these three,
the capillaries are most important in their function, since they not
only carry blood, but owing to the peculiarity of their walls,

40 ESSENTIALS OF HUMAN PHYSIOLOGY.

bring the blood into intimate relation with the tissues. The fluid
which escapes from the capillaries is known as lymph, and the
function of lymph is to irrigate and nourish.

What is the difference between arteries and veins ?

Arteries differ from veins in having thicker walls, owing to a
greater development of their outer coats.

Remember! The fact that arteries do not contain valves is not
a differential point, since some veins contain no valves.

Also that they are not differentiated by the kind of blood they
carry, but by their structure ; the pulmonary artery carries venous
blood, while the pulmonary veins carry arterial blood.

How many coats have the arteries ?

They have three coats, known as the outer, or tunica advent iti a ;
the middle, or tunica media; the inner, or tunica intima. The last
of these is made up of transparent endothelium, composed of
irregular, long, fusiform cells held together by a cement substance
which is stained black by nitrate of silver (AgN03). Outside the
endothelial coat lies a very thin, more or less fibrous layer, the
sub-endothelial ; and outside of this is the elastic lamina, which in
the smallest arteries amounts to nothing more than a structureless
or fibrous membrane, whilst in the other vessels its function is
most important. It is known as the fenestrated membrane. The
tunica media contains much unstriped muscular fibre, which
increases in amount as the vessel grows larger. Most of these
fibres are circular, completely surrounding the vessel, while a
much smaller number run longitudinally. The tunica adventitia,
or the outer coat in the smallest arteries, is a structureless mem-
brane which changes into a fibrous membrane as the vessel
increases in size.

What are the functions of these coats ?

The endothelial layer forms a smooth surface over which the
blood may pass, and the importance of this will be understood
when it is remembered that rough surfaces aid in the coagulation
of the blood. The muscular coat regulates the amount of blood
received by each part and governs the elastic coat. This is neces-

THE HEART. 41

sary, since it is manifest that the heart cannot regulate the blood-
supply of each portion of the body.

Does the muscular coat aid in the propulsion of the
blood ?

No ; it must be distinctly remembered that in the higher
animals, particularly in man, the muscular coat probably aids very
slightly in the propulsion of blood.

In what way do these coats aid in arresting- hemor-
rhage ?

The muscular coat aids, in conjunction with the elastic coat, in
the prevention of extensive hemorrhage by contracting the open-
ing in the bloodvessel, turning in its edges so that the opening is
greatly decreased in calibre.

What other function has the elastic coat ?

A more important function of the elastic coat is the prevention
of sudden pressure in any portion of the body by yielding partially
to a sudden strain or controlling a tendency to too great a dilata-
tion. It, therefore, equalizes blood-pressure during diastole and
systole, and were it not for this important coat the arteries would
be entirely emptied during diastole and filled to bursting during
systole.

What is the function of the outer fibrous coat of the larger
bloodvessels ?

To protect the bloodvessels from injuries from the exterior and
to give the bloodvessel walls support. If it were not for the fibrous
coat a ligature applied to a vessel would cut through.

What have we in some veins which do not occur in
arteries ?

Valves which flap back against the wall of the vessel as the
blood flows onward, but which prevent any reflux .should the
current be reversed by any cause.

42 ESSENTIALS OF HUMAN PHYSIOLOGY.

How are these valves arranged, singly or in pairs ?
In pairs.

[s there any difference in the capacity of the various
portions of the vascular system ?

The combined calibre of the branches of an artery exceed in
their capacity that of the parent trunk, and so soon as the muscular
coat of an artery is past the capacity of the vascular system is
enormously increased. The capillaries are capable of holding
eight hundred times as much blood as the aorta. The veins
diminish in area as they come toward the heart, whilst the arteries
increase as they go toward the periphery. The capacity of a vein
is always greater than that of a corresponding artery : even at the
heart the capacity of the venae cavse is twice as great as that of
the aorta.

Fig. 3.

Diagram intended to give an idea of the aggregate sectional area of the different
parts of the vascular system. A. Aorta. C. Capillaries. V. Veins. The transverse
measurements of the shaded part maybe taken as the width of the various kinds of
vessels, supposing them to be fused together. (Yeo.)

What do you mean by blood-pressure ?

The pressure under which the blood stream is kept by the action
of the heart and the walls of the bloodvessels.

THE HEART. 43

Is the blood pressure always constant in man and animals ?
The blood pressure varies from many causes, and differs in nearly
all animals. In the rabbit it can support a column of mercury
from two to three and a half inches in height, in the dog from four
to five and a half inches, in the horse from eight to twelve inches,
while in man the pressure will hold a column of mercury as high
as five and three-fourths inches. The pressure in the human aorta
is estimated at four pounds and four ounces, in the horse eleven
pounds and nine ounces, in the radial artery of man at four drachms,
in the pulmonary artery two pounds and two ounces. But it must
be remembered that these figures represent the maximum amounts
at the moment of ventricular systole. The pressure is least in the
capillaries, greatest in the aorta. The venous pressure is only
one-tenth that of the arterial pressure.

What is the influence of the nervous system on blood
pressure ?
Nerves supply all the arteries and arterioles, and even the capil-
laries and veins, and belong to the so-called sympathetic system.

What are these nerves called ?
Vaw-motor nerves.

How are they arranged and governed ?

By a centre in the medulla oblongata known as the vnso-motor
centre, which is situated near the calamus scriptorius and the cor-
pora quadrigemina, the tension of the vascular system is governed.
Fibres from this centre pass down in the neck through the spinal
cord, and find exit with the anterior roots of the spinal nerves.
The vaso-motor centre is probably always at work, and to aid it we
have scattered through the spinal cord, and in various portions of
the body, lesser centres under its control, but capable of originating
impulses themselves.

What proof have we that this is so ?

If the cervical sympathetic be cut on one side in the rabbit, or
in any animal, that side of the head becomes very rapidly deeply
suffused and congested, and remains in this condition tor many
hours. Finally, however, the color returns almost to normal, and

44 ESSENTIALS OF HUMAN PHYSIOLOGY.

congestion goes down. The first dilatation was due to the fact that
the governing centre in the medulla by the section, was cut off from
that side, and the minor centre not being accustomed to send out
powerful impulses, is unable to govern its tributary bloodvessels.
In a short time, however, the local centre gathers power, and once
more exerts not only its previous influence over the vascular supply
of that side, but also is enabled to supplement the action of the
higher centre in the medulla, which, before the section, constantly
aided it in its efforts.

What effect has stimulation of the vaso-motor system on
blood pressure ?
It raises it by contraction of the bloodvessels all over the body.

What effect has depression of the vaso-motor system on
blood pressure ?

It lowers it by dilatation of the bloodvessels.

What effect has division of a vaso-motor nerve on its
tributary vessels ?
It produces palsy, or relaxation, of its tributary muscles in the
wall of the bloodvessel, and, as a consequence, a local or, if the
vessels are large enough, indirectly a general fall in blood pressure,
by drawing a large amount of blood from the general system.
Stimulation of a nerve, on the other hand, produces a contraction
of these muscles and a rise of pressure. Blushing is a good example
of vaso-motor disturbance of the nervous apparatus governing the
vascular system.

What effect has galvanization of a sensory nerve on
general blood pressure ?

It raises it.

What effect has it on bloodvessels of a leg in which the
sensory nerve is galvanized ?

It dilates them and locally lowers pressure.

What effect has asphyxia on blood pressure?

It increases it by stimulation of the vaso-motor centre in the
medulla by the increased amount of C02 in the blood.

THE HEART 45

What effect has section of the spinal cord on blood pres-
sure ?
It produces a great fall in pressure, due to the cutting off of the
vaso-raotor centre in the medulla from the vascular system all
through the body.

What effect has paralysis of the vaso-motor nerves supply-
ing the abdominal bloodvessels ?
A general fall in blood pressure all over the body.

Why is this so ?

Because these bloodvessels are capable of holding all the blood
in the body, and so starve the rest of the vascular system.

What other causes increase arterial pressure ?

Increased heart action, whereby more blood is driven out into
the bloodvessels in a given space of time. The increase in heart
action may be by increased rate or force, the result is tbe same.

What are the physical forces of the circulation ?

Liquid always goes away from pressure, and the pressure depends
on the ease of escape and the forces from behind. If a tube be
elastic, and its distal end open and small, it will be found that
though the liquid enters it in jerks at the proximal end, it will
leave the distal end in a steady stream, but if the tube is rigid the
liquid moves in jerks along its whole length. This is the key to the
circulation.

Under what conditions is the blood placed after being
driven out of the ventricle into the arterial system?

Just before the arteries are changed into capillaries they are
known as arterioles; it is in these arterioles that we still have the
muscular coat quite powerfully developed and governed by the
vaso-motor system. These muscular coats are kept at a certain
degree of tonicity, producing thereby a considerable narrowing
of the blood paths, and they, therefore, prevent the blood from
flowing out into the capillary system too rapidly. On the other
hand, the force given to the blood by the heart has so distended

46 ESSENTIALS OF HUMAN PHYSIOLOGY.

the arterial system, particularly in the larger trunks, that the
elastic coats have been greatly stretched, and no sooner does
the pressure from the heart muscle cease than they contract on
the blood. Pressed upon in this manner on all sides, the blood
endeavors to find some mode of exit, and is prevented from
regurgitating back into the ventricle, in health, by the valves
at the aortic opening. As a consequence, the blood obeys the
physical law already mentioned, and passes in the direction of least
resistance, namely, through the contracted arterioles.

What is the function, therefore, of the arterioles ?

To prevent too rapid a flow into the capillary system, which, if
permitted, would immediately starve both the arteries and veins of
their proper amount of blood, since, as before noted, the capacity
of the capillaries is extremely great.

What aids blood flow in the capillaries ?

Capillary attraction and pressure due to muscular movements of
the body. Also to the action of the heart and arterial coats.

What aids blood flow in the veins ?

Lateral pressure exerted by contraction of the voluntary mus-
cles of the body, the indirect action of the valves in the veins, and,
to a slight degree, the heart force. Also, the suction produced by
movements of the thorax in respiration (not the heart).

Does the blood find it more difficult to return through the
veins than to descend through the arteries ?
No ; the circulation in this respect resembles a U-shaped tube
filled with mercury, in which the column rises on one side, due to
pressure or displacement on the other. In other words, the blood
descending in the femoral artery shoves the blood up the corre-
sponding vein.

Is there difference in the rapidity of the flow of the blood
in the arteries, capillaries, and veins ?
Yes; in the artery the flow is very rapid and in spurts, in the
capillaries it is many times slower and generally moves in a steady

THE HEART. 47

stream. In the veins the rapidity of the now increases as the
blood nears the heart, but moves in a steady stream, and does not
attain the speed of the blood in the arteries.

What is the pulse ?

The pulse is caused by a wave of force which travels along
the column of blood in an artery as a direct result of a single
contraction of the heart; in other words, each pulse represents
a heart beat, but not the blood thrown out at that beat. The
stroke given by the heart in propelling the blood onward is
expended in causing not only the forward movement of the whole
mass of blood, but also the lateral expansion already spoken of.
As a consequence of this, each pulse is like an expansion wave,
causing the vessel to expand by reason of the increased tension
and force produced by the heart from behind.

Is the rapidity of the pulse wave the same as the rapidity
of the blood stream in the artery ?
No ; the main current passes along the vessel at a given rate of
speed, while the force of each systole is transmitted along the
blood stream as if it were a solid piece of metal or wood, which,
having been struck at one end, transmits a wave of force to the
other end. The blood being enclosed in partially rigid walls
carries the impulse chiefly forward, not laterally. The pulse wave
is twenty or thirty times as rapid as the blood current its* It.

Does the pulse cause simply a lateral dilatation of the
bloodvessel?
No ; the bloodvessel is not only widened, but lengthened, so that
a straight artery may he seen not only to dilate, but also to become
curved to make up for its elongation.

Is the pulse wave equally strong in all portions of the
body ?
No; it diminishes in force and in speed as it travels onward, due
to the force expended in distending successive parts of the blood-
vessel, friction, and other causes. As a consequence of this the
pulse in certain portions of the body occurs an appreciable l<
of time after the cardiac contraction which has produced it. This

48 ESSENTIALS OF HUMAN PHYSIOLOGY.

is noticed particularly in the radial artery, or markedly in the dor-
salis pedis artery. The delay, however, even at the most distant
point amounts to not more than one-sixth to one-eighth of a second.

At what speed does the Wood circulate ?

About ten metres or thirty-five feet per second, and takes but
one-third of a second to pass a given point. The length of each
pulse wave is, therefore, about three metres (9J feet), or twice the
length of the longest artery. When the last part of the pulse
wave has passed the arch of the aorta the first part has just reached
the arterioles.

RESPIRATION.

The respiratory apparatus is divided into the larynx, trachea,
bronchial tubes, bronchioles, and vesicles in the lung. Surround-
ing each lung are the pleurae, one layer of which is attached to the
lung (visceral layer), the other to the chest wall (parietal layer).

What is the object of respiration ?

In order to bring the oxygen of the air in close relationship
with the haemoglobin in the blood, and to permit of the elimination
of C02 from the body, as well as other effete products in very
minute amount. The enlargement of the chest occurs with inspi-
ration, the contraction of the chest with expiration.

How many varieties of blood-supply exist in the lung ?

Two; the pulmonary artery supply, and the bronchial artery
supply.

What is the function of these two varieties ?

The pulmonary artery supplies the blood for aeration, the
bronchial artery that for the nourishment of the lung-tissue itself.

In what manner is the blood brought to the vesicles and

exposed to the air ?

The smaller branches of the pulmonary artery split up more

and more, and have the peculiarity that they do not anastomose with

one another. The fine capillaries run between the air vesicles, the

RESPIRATION. 49

thin wall of the vessel and vesicle permitting the free interchange
of gases to take place.

What difference do we have in the distribution of the
bronchial and pulmonary veins from that of the
arteries ?
The pulmonary and bronchial veins anastomose with one another.
Is the circulation more or less rapid in the lung capillaries
than elsewhere?
More rapid, since their area is not so great.

Why are the pulmonary veins slightly smaller than the artery?
On account of the lessening of fluid due to exhalation of moist-
ure in respiration.

Are the movements of the lung passive or active ?

They are passive, merely following the movements of the chest
walls.

What are the movements of inspiration ?

In inspiration all the diameters of the thorax are increased.
The lateral or transverse diameter is increased by the raising of
the ribs ; the shape of the ribs and their relation to the vertebral
column are such as to carry them outward at the same time that
they are raised. This same movement carries the sternum for-
ward, thus increasing the antero-posterior diameter. The increase
in the vertical diameter is due to descent of the diaphragm, the
dome-shaped surface of which becomes less arched. For this
reason the diaphragm is the most important respirator// muscle.

The other muscles concerned in the inspiratory act are the
quadrati lumborum, serrati postici inferiores, scaleni, serrati pos-
tici superiores, levatores costarum longi et breves, and intereos-
tales externi et intercartilaginei.

In forced inspiration the following muscles supplement them :
sterno-cleido-mastoidei, trapezii, pectorales minores, pectorales ma-
jores (costal portion), thromboidei, and erectores spina?.
What are the movements of expiration ?

Ordinary expiration is a passive act, brought about by the elastic
tension of the lungs, costal cartilages, abdominal viscera, and ab-
dominal walls, aided by the weight of the thorax. Contraction of
the intercostales interni interossei may assist. In forced expiration

4

50 ESSENTIALS OF HUMAN PHYSIOLOGY.

these muscles are active, as are also the triangulares sterni, mus-
culi abdominales, and levatores ani.

What effect has sex on respiration ?

In men respiration is largely abdominal or diaphragmatic; in
women chiefly costal or thoracic. These differences are not due to
sex, but to dress and heredity. In young children respiration is
chiefly diaphragmatic.

Which is longer, inspiration or expiration ?

The mean ratio of inspiration to expiration is as 5 : 6.

What sounds do we hear on listening to the chest ?

The respiratory murmurs, which are produced by the passage of
the air in and out of the respiratory apparatus.

What do you mean by "tidal air"?

The ordinary volume of air respired, amounting to about thirty
cubic inches in the adult.

What do you mean by "reserve air"?

The air which can be voluntarily emitted after ordinary expira-
tion. It amounts to about one hundred cubic inches.

What do you mean by " complemental air"?

The amount which can be taken in after an ordinary inspiration.

What do you mean by "residual air"?

It is the amount which remains after forced expiration, equalling
about one hundred and twenty cubic inches.

What does the term "vital capacity" mean?

The greatest amount of air which can be emitted after forced
inspiration, and is therefore the sum total of reserve, tidal, and
complemental air. It varies with age, sex, size, posture, and oc-
cupation. The total quantity in an adult, passing in and out in
twenty-four hours, is 686,000 cubic inches; in hard-working labor-
ers, 1,568,390 cubic inches. For every inch of height above five
feet one inch the capacity should increase eight cubic inches.

What influence has sex on capacity ?

Females have less capacity than males where the chest has the
same circumference.

RESPIRATION. 51

How many respirations a minute ?
Fourteen to twenty, but the number is influenced by Bex, the

age, and position, also by exertion. Thesi/.e ot'tbe animal governs
rapidity. The mouse breathes very rapidly; the elephant only
eight times per minute.

What effect has the law of the diffusion of gases on res-
piration ?
In the vessels we have a large amount of C02, while in the air
we breathe we have an excess of O. According to this law, there-
lore, the 0 attempts to get in as the CO, attempts to get out. This
law also prevents the reserve and residual air from becoming laden
with ( _'< ).,. The change is assisted, too, by the different temperatures
of the air within and without.

What amount of work is performed by the respiratory
muscles ?

The work done by the respiratory muscles is estimated by
Haughton at 21 foot-tons in twenty-four hours.

What changes have we produced in the atmospheric air
by respiration?

1. Increase in its temperature.

2. Increase in C02.

3. Increase in organic matter and free ammonia.

4. Increase in watery vapor.

5. Diminished amount of O.

The expired air is hotter than the inspired as a general rule,
but on a hot day, with the atmosphere al>ove <k.s° 1'., it is cooler.

The temperature varies from 97°-99^. 1\. according to the
length of time the air remains in the lungs.

Is the amount of CO. exhaled constant?

It varies at all hours of the day, and is influenced by many con-
ditions. The C02 given off by a normal man in an hour equals
1346 cubic inches, or 636 grains. Accordingly we have 173 grains
of carbon given off in an hour, or 8 ounces in twenty-four hours.

Time of day, varieties of food, and exercise, greatly influence
the amount of (.'( >.,.

52 ESSENTIALS OF HUMAN PHYSIOLOGY.

Does age affect the amount of COJ

Yes ; C02 increases in amount from 8 to 32 years, while from
35 to 50 it remains stationary, or slightly falls. After 50 years it
constantly diminishes. At 80 years it scarcely exceeds that of a
child of 10 years.

How much 0 is abstracted from every volume of air ?

About 4\ per cent,

What effect has quickening of the respiratory movements
on the amount of C02?

The quicker the respirations the less C02 in each respiration,
but the aggregate amount is increased.

What portion of the expired air contains the most C02?

That of the last half of expiration.

What effect has the condition of the atmosphere on the
amount of C02?

More C02 is given off when air is moist than when it is dry.

What influence has the time of day on the relative amounts
of C02 and 0 ?

During the day more C0.2 is exhaled than O is taken in; while
at night the reverse is the case. In other words, there is a reserve
fund of O stored up at night to meet the exigencies of the day.

Is a very large amount of watery vapor given off by the
lungs ?
Yes ; almost enough to saturate the expired air. The amount
equals 6 to 27 ounces in twenty-four hours. The average amount
is from 0 to 10 ounces.

Does ammonia exist as a physiological constituent of all
expired air?

No; it does not. It is chiefly derived from decomposition pro-
ducts in the mouth.

RESPIRATION. 53

The Nervous Mechanism of Respiration.

Is respiration purely an involuntary act ?

No, it is not; since we can "hold the breath,'' or breathe rapidly
or slowly, superficially or deeply, as we choose. That it is in-
voluntary to a great extent is proved by the fact that one does not
stop breathing when asleep or unconscious.

Respiration is governed by a centre, the respiratory centre, in
the medulla oblongata near the calamus scriptorius.

What keeps this centre active ?

It is kept active by the condition of the blood. If the amount
of O is too small the centre sends out impulses and increases
respiration.

Describe this centre more fully.

There is a respiratory centre on each side of the medulla
oblongata, and these may in turn be divided into two centres,
namely, the greater one for inspiration and lesser for expiration.

Does the expiratory centre constantly send out impulses ?

\<>; it is only active on rare occasions, as when there is some
obstruction to respiration.

Are there any centres for respiration higher up in the
nervous system than the medulla oblongata ?
No. All phenomena which have suggested such a centre can
easily be explained as centripetal stimulations of the medulla
oblongata, which hy reflex action act on the respiratory centre in
the fourth ventricle.

Are there any respiratory centres in the cervical part of
the cord ?
No. Only the tracts which carry the impulses.

What do you mean by eupnoea, apncea, and dyspnoea ?

Eupncea is normal breathing; apncea is a condition in which too
much O is absorbed into the blood, and is readily produced by
forced artificial respiration. Remember, that the use of the word
apncea to indicate a condition in which breathing has ceased froir.
the ordinary causes, is incorrect. Breathing in apnoea ceases from

54 ESSENTIALS OF HUMAN PHYSIOLOGY.

the excess, not the lack, of oxygen. Dyspnoea is labored or diffi-
cult breathing.

What effect has the pneumogastric apparatus on respi-
ration ?
If both vagi are cut the respirations become somewhat deep and
full. If these nerves are stimulated the respirations become very
rapid and violent.

Is this change due to a direct transmission of the stimulus
along the nerves to the lungs, or to a reflex wave
to the respiratory centre ?

It is due to a reflex wave to the respiratory centre. Remember,
that the vagus nerves are made up of both efferent and afferent
fibres. Also remember, that not only do we have an efferent and
afferent set of fibres, but that the afferent fibres are made up them-
selves of two sets of fibres, one of which, the central end of the
superior laryngeal branch, after it has been cut, when stimulated
slows the respirations, while stimulation of the central end of the
vagus itself quickens the respirations. When the nerve is stimu-
lated the impulse goes upward to the centre, and from there is
irradiated down to the organs.

Si<jhing is a long inspiration. When great attention is being
paid we speak of " shallow breathing." In other words, we almost
forget to breathe. Sighing always follows this condition, and
makes up for the shallow breathing before it.

Hiccough is a sudden inspiration due to descent of the diaphragm.

Coughing is expiratory.

Sneezing is expiratory, but is preceded by a full inspiration.

In speaking we expire.

Sobbing consists of a series of short inspirations, after each of
which the glottis is closed.

Laughing is a series of short and rapid expirations.

DIGESTION.

What three forms of digestion have we ?
Salivary, gastric, and intestinal.

DIGESTION. 55

What is the function of salivary digestion ?

To convert starch into maltose.
On what does the gastric digestion act ?

( )n the proteids, converting them into peptones.

What part of digestion is carried on in the small intestine ?

The fats art' prepared for absorption by being emulsified, the
proteids converted into peptones, and starch is changed to maltose
and dextrose

The salivary secretion is derived from what three glands ?

The submaxillary, sublingual, and parotid. The mucous glands
present in the mouth are solely for the purpose of lubrication.

Describe the characteristics of the saliva.

It is a mixture of the secretion of the three glands named, and
is a slightly turbid, tasteless fluid of a distinctly alkaline reaction.
The specific gravity is 1003. It contains five-tenths per cent, of
solids, the greater part of which are organic, such as mucin, which
produces the viscidity, traces of albumin, and a peculiar ferment,
ptyalin. The inorganic constituents are salts, the chief one of
which is potassium sulphocyanide, which may be readily per-
ceived by its odor when saliva is kept for a short time in a test
tube. The other portions of the saliva are made up of salivary
corpuscles which contain nuclei, and are probably altered leuco-
cytes, epithelial cells, and various microorganisms.

How much saliva is secreted in twenty-four hours ?
From 7 to 70 ounces.

What is the difference between parotid saliva and that of the
other glands ?
It contains more ptyalin, a smaller amount of urea, traces of
a volatile acid, and some inorganic constituents, as >alts of soda
and potash ; it contains no mucin, and is much thinner than is the
secretion of the submaxillary or sublingual glands.

Describe the submaxillary saliva.

Submaxillary saliva is markedly alkaline, tenacious, and con-
tains mucin; it contains much less ptyalin than does parotid
saliva.

56 ESSENTIALS OF HUMAN PHYSIOLOGY.

Describe the sublingual saliva.

Sublingual saliva is more sticky and cohesive than either of the
others, and contains much mucin, salivary corpuscles, and potas-
sium sulphocyanide.

What is the nerve supply of the salivary glands ?

The submaxillary glands are supplied by the chorda tympani,
which is derived from the facial nerve. It also receives filaments
from the superior cervical ganglion of the sympathetic, and from
the submaxillary ganglion.

Remember, that the chorda tympani contains two sets of fibres:
1st, true secretory fibres ; 2d, vaso-dilator fibres.

The sympathetic also contains two sets of fibres : 1st, true secre-
tory ; 2d, vaso-constrictor fibres.

The sublingual glands are supplied by the same nerves as supply
the submaxillary. The parotid glands are supplied by branches of
the facial which join the auriculo-temporal branches of the fifth
pair of cranial nerves.

What is the effect of section of the chorda tympani ?

The flow of saliva is very greatly decreased.

What is the effect of stimulation?

Increased salivary flow and increased glandular vascularity.

What is the effect of stimulation of the facial nerve at its
origin in the floor of the fourth ventricle ?
It increases the salivary flow from the submaxillary gland.

What is the effect of stimulation of the sympathetic ?

It causes a decrease in the salivary flow, with contraction of the
bloodvessels and consequent decrease in vascularity.

Does the increase in salivary flow depend upon increased
vascularity ?
No ; since if all the bloodvessels going to the gland be tied, secre-
tion is still increased either when the chorda tympani is stimulated
or when the sympathetic is paralyzed ; under these circumstances
the extra liquid required is obtained from the lymph vessels and
spaces. Atropine and daturine are drugs which decrease salivary
secretion by depressing the chorda tympani peripherally.

DIGESTION. 57

Remember, that mere increase in vascularity in the salivary glands
does not of necessity increase the flow of saliva. The only influence
which increased vascularity exerts is a greater supply of liquid
which escapes from the gland rather by leakage than by secretion.

Is the pressure in the excretory ducts of the salivary glands

very great ?

Yes ; Ludwig has found that the pressure in these ducts may be

twice as great as the blood-pressure in the carotid itself. The

pressure in Wharton's duct may equal 200 millimetres of mercury.

What is the cause of the great pressure in the salivary
ducts?
It is due to the secreting power of the cells in the gland.

What change in temperature occurs in the gland ?

During secretion the temperature of the gland rises, so that it is
often warmer than the arterial blood.

How do you produce increased salivary flow from the
parotid 1

By stimulation of the facial nerve after it has joined the auriculo-
temporal branch of the fifth or trifacial nerve, or reflexly by stimu-
lation of the glosso-pharyngeal nerve.

In what way is secretion brought about when food enters
the mouth?
Reflexly through the lingual branch of the glosso-pharyngeal
and the inferior maxillary branch of the trifacial or fifth nerve,
which carry the impulses up to the centre in the medulla.

What effect has section of the chorda tympani on this
reflex ?
If the chorda tympani be cut previous to the introduction of a
substance into the mouth no increase of flow comes from the glands
which it supplies; but if the sympathetic be cut the reflex, although
partially interfered with, is not prevented.

Is the rate of secretion always the same ?

No ; it varies according to the condition of the mouth and the
food in it.

What effect have the movements of mastication on the
salivary flow ?
They increase it.

58 ESSENTIALS OF HUMAN PHYSIOLOGY.

In what condition is an increased flow of saliva pro-
duced?
When nausea is present, profuse salivary secretion occurs by a
reflex through the vagus nerve.

What is the physiological action of saliva ?

Its most important action is its diastatic or amylolylic action, or,
in other words, the transformation of starch into dextrins, and of
dextrins into maltose.

What do you mean by the term diastatic ?

The power which certain substances have of acting on starch
and converting it into sugar.

Upon what does the diastatic power of saliva depend ?

Upon ptyalin .

Is the ptyalin destroyed when it acts ?

Scarcely at all, for it acts by catalysis, or its mere presence.

What effect have high and low temperatures on the action
of ptyalin?
High and low temperatures prevent its action, and boiling and
freezing stop it absolutely.

What is the sugar called which is formed by the action of
the saliva ?
The sugar formed by the action of saliva on starch is called
maltose, which is converted into dextrose by an inverting enzyme
in the small intestine. It is in the form of dextrose, or dextrose
and levulose, that the carbo-hydrates are absorbed.

What is the object of boiling starchy foods ?

In order to break up the cellulose coverings of the starch gran-
ules, and enable the diastatic ferment to attack the starch.

What is the first change in the starch as it is digested ?
It becomes liquefied.

What are the mechanical uses of saliva ?

It keeps the mouth moist, facilitates speaking and the mastica-
tion of food, also the movements of the tongue. It dissolves
certain substances, and renders them capable of being tasted ; by

DIGESTION. 59

mixing with food it forms a soft bolus which is easily swallowed
and digested.

What are movements of mastication ?

1. The elevation of the jaw is accomplished by the combined
action of the temporal, masseter, and internal pterygoid muscles.

2. The depression of the jaw by its own weight, aided by the
action of the anterior bellies of the digastrics, mylohyoids and
genio-hyoids, and the platysmas.

3. The displacement of the articular surfaces backward or for-
ward is produced, when forward, by the external pterygoid muscles
which pull the jaw down and forward. As one external pterygoid
acts it pulls the jaw sideways and we have a grinding movement.
When the movement is backward the digastric and hyoid muscles
act.

What is the function of mastication ?

We divide, by this means, the food into small pieces, biting it
off by the incisors, tearing it off by the canines, and grinding it
up by the molars. Soft food is broken up by the tongue pressing
it against the roof of the mouth. By this means the digestive
fluids may attack the food more readily.

What is the function of the tongue in mastication?

To keep the food between the teeth, in which it is assisted by
the muscles of the lips and the buccinator muscles.

In what way is deglutition accomplished ?

1. The aperture of the mouth is closed by the orbicularis oris.

2. The jaws are pressed together by the muscles of mastication.

3. The tip, middle, and root of the tongue, one after the other,
are pressed against the hard palate, thereby propelling the food
backward. Just at this time the levator palati draws the soft palate
upward and backward, completely closes the posterior openings oi
the nasal cavities, and the intrinsic muscles of the larynx firmly
close the rirna glottidis.

4. After the anterior palatine arch is passed, it is prevented from
returning to the mouth by the palato-glossi muscles, lying in the
anterior pillars of the fauces.

5. The bolus is now urged on, first, by the action of the superior
constrictors of the pharynx, next the middle, and third the inferior
constrictors.

60 ESSENTIALS OF HUMAN PHYSIOLOGY.

6. Having reached the cesophagus, it is urged on by the outer
longitudinal and the inner circular non-striped muscular fibres,
which contract peristaltically. Recent experiments show that this
peristalsis only occurs on forced deglutition, the food ordinarily
being projected into the oesopbagus by the voluntary muscles.

What is the nervous mechanism of deglutition ?

The centre for swallowing is in the medulla oblongata. The
efferent nerves which govern deglutition are : the hypo-glossal,
which supplies the hyoid or tongue muscles ; the glosso-pharyngeal
and vagus nerves to the pharyngeal plexus, which supply the con-
strictor muscles; and the facial and fifth, which supply the fauces
and palate. The movements of the cesophagus are governed both
afferently and efferently by the vagus, which also acts with the
superior maxillary branch of the trifacial. The afferent vagus
filaments for the first part of deglutition are the pharyngeal
branches of the anterior laryngeal branches.

The Stomach.

What varieties of cells do we find in the stomach ?

In the cardiac end of the stomach we have two distinct kinds
of cells. One kind, the most numerous, consists of small, pale,
spheroidal cells which line the interior of the glands. The other
cells are much fewer as well as larger, and are scattered over the
fundus of the glands.

What two sets of glands have we in the stomach ?

The mucous, which are chiefly situated at the pyloric end of the
stomach, and those which secrete gastric juice.

What are the movements of the stomach ?

When the stomach is empty it lies with its greater curvature
downward and its lesser upward ; when it is full the greater cur-
vature swings forward against the abdominal wall, while the lesser
curvature approximates itself to the spinal column.

What other gastric movements have we?

We have two distinct varieties of gastric movement different
from the two mentioned : the first is a rotatory or churning move-
ment whereby the walls glide over the food, these movements occur
periodically and last for several minutes, their function is to
moisten the food by the gastric juice and break it up ; the other is

DIGESTION.

61

Fig. 4.

Diagram of a section of the wall of stomach, o, orifices of gland*, with cylindrical
epithelium, b, fundus of glands, wirh spherical and oval epithelium, c, muscularis

mucosae, d, submucous tissue, containing bl (vessels, etc. e, circular ; /, oblique, and

g, longitudinal muscle coats, ft, serous membrane.

Fig 5.

•

Mi

Diagram showing the relation of the ultimate twigs of the bloodvessels (V and A) and
of the absorbent radicals (L) to the glands of the stomach, and the different kinds of

epithelium, viz.: above cylindrical cells; small, pale cells in the lumen ; outside of which
are the dark ovoid cells. (Yeo.)

62 ESSENTIALS OF HUMAN PHYSIOLOGY.

the peristaltic movement whereby the food is pushed out into the
duodenum through the pylorus.

What are the intrinsic and extrinsic nerves of the stomach ?
Auerbach's plexus is the motor portion of the apparatus. The
left vagus supplies the anterior surface of the stomach, the right
vagus supplies the posterior surface.

Describe the gastric juice.

It is a tolerably clear, colorless fluid (straw-colored), of acid reac-
tion, sour taste, and peculiar characteristic odor; it is not rendered
turbid by boiling and resists putrefaction for a long time; its spe-
cific gravity is 1002.5. The quantity secreted in twenty-four hours
amounts to from eight to fourteen pints.

What does the gastric juice contain?

First, pepsin, the characteristic nitrogenous hydrolytic ferment,
which dissolves proteids; second, hydrochloric acid, the chief acid
present; also small amounts of lactic acid. The latter, however, is
not secreted, but is due to decomposition of carbo-hydrates in the
stomach.

Which cells secrete the greatest amount of pepsin?
Those at the cardiac end of the stomach.

Does pepsin exist in the glands ready formed?

According to most physiologists it is due to the presence of a
compound known as pepsinogen, which forms pepsin as soon as
it comes in contact with hydrochloric acid in the stomach.

What is the function of lactic acid ?

It digests the proteids in much the same manner as does hydro-
chloric acid.

Does secretion go on constantly in the stomach ?
No. Only on the entrance of stimuli, such as food, etc.

What change takes place in the gastric mucous membrane
on the entrance of food ?

It becomes red and the circulation more active.

What happens to the gastric juice when the food passes
out of the stomach into the alkaline intestine ?
It is neutralized and part of the pepsin reabsorbed.

DIGESTION. 63

What is chyme ?

The mixture of food and gastric juice.

What effect has gastric juice upon proteids ?

It changes the proteids first into a substance known as syntonic
or acid-albumin, which is immediately changed again into pro-
peptone or hemi-albuminose or para-peptone. The para-peptone
h now converted into peptone, which is absorbed into the blood
from the small intestine and immediately converted back again
into proteids, and so deposited in the tissues.

Does pepsin suffer any change when acting ?
It acts chiefly by catalysis, but is partially destroyed.
(For properties of peptones and para-peptones, see page 19.)

Is any albumin absorbed unchanged ?

According to Yeo, a considerable quantity of albumin is absorbed
unchanged, both from the stomach and intestines.

What other special ferment have we in the stomach?
The milk-curdling ferment.

What is the action of the gastric juice on carbo-hydrates?

It has no effect on starch, inulin, or the gums. Cane-sugar is
slowly changed by it into dextrose and levulose.

Why does not the stomach digest itself?

There is much discussion in regard to this point. Xo satisfac-
tory explanation has been given. Some physiologists teach that
the protection which the coats of the stomach, during life, seem to
have is due to the constantly circulating alkaline blood through
them.

This explanation is unsatisfactory, as it does not explain why
the small intestine is not digested by its alkaline fluids. All that
can be said in either case is that living tissue is protected from
self-digestion by the properties of its living structure.

What gases have we in the stomach ?

Those which are derived from the air which is swallowed with
the saliva and those which regurgitate from the duodenum. Besides
these we have gases which arise in eases of dyspepsia from fermen-
tative and putrefactive changes in the food.

64 ESSENTIALS OF HUMAN PHYSIOLOGY".

What is the mechanism of vomiting ?

It is caused by contraction of the walls of the stomach, whereby
the pyloric sphincters are closed. It occurs most easily when the
stomach is distended, and in infants, owing to the peculiarity of the
position of their stomachs, the regurgitations of milk are due to
scarcely more than reverse d peristalsis. In children, therefore, the
abdominal muscles do not always aid in the expulsion of food. In
adults they always do.

In what way is vomiting produced ?

Vomiting is produced either by an action on the peripheral ends
of the nerves of the stomach or by direct action on the vomiting
centre in the medulla.

What effect has section of the vagi on vomiting ?
It prevents it.

Do we ever have bile in vomit ?

Frequently when the vomiting is so severe as to cause the bile
to flow out of the duodenum into the stomach.

What is the movement called by which food is passed
along through the intestines ?

Peristalsis.

In what portion of the intestinal tract is peristalsis most
marked ?

In the small intestine.

What is peristalsis ?

Peristalsis is the constantly moving onward of a contractile wave
along the wall of the gut, or, in other words, is the progressive
narrowing of the tube from above downward.

Do the movements of the stomach and intestine continue

during sleep ?

Some physiologists believe that they do ; others that they do
not. The matter is largely one of opinion, but it is probable that
the first opinion is the correct one.

DIGESTION. 65

What do you mean by reversed peristalsis ?

A condition in which the peristaltic wave travels from below
upward, the cause of which has been supposed by sonic to be due
to the fact that one band of the muscular fibres in the gut misses
a contraction.

What are the functions of the muscular coat of the intes-
tine ?
To carry on peristalsis.

What nervous influence is exercised over intestinal move-
ments ?
Auerbach's plexus is the automatic motor centre which lies
between the muscular coats and produces peristaltic movements
iu sections of the gut removed from the body. Meissner's plexus
is much less important, supplying only a few motor fibres to the
muscular coats, and a few motor and sensory fibres to the muscularis,
mucosa?, and intestinal glands.

What do you mean by aperistalsis ?

An absolute abolition of peristaltic movement. Normal peris-
talsis is known as euperistalsis. When peristalsis becomes very
violent it is known as dy aperistalsis.

What influence has the circulation of the blood on peri-
stalsis ?
Violent peristaltic movement is produced by interrupting the
circulation of blood in the wall of the gut, whether the stoppage is
due to congestion or anaemia of the parts. This is the cause of the
marked peristalsis preceding death.

What are the inhibitory nerves of the gut ?

The splanchnics, which, however, also contain motor filaments.

What effect has stimulation of the splanchnics on peri-
stalsis ?
If the blood supply is normal it slows or prevents them. If
abnormal, it increases them. The reason of this is that the inhibi-
tory fibres of the splanchnics are paralyzed by venous blood in the
gut, but the motor fibres are not.

66

ESSENTIALS OF HUMAN PHYSIOLOGY.

Pancreatic Digestion.

Describe the pancreas.

The pancreas is a large racemose gland attached by its lateral
branchlets to its main central duct. The cells making up the
gland may be divided into two zones, an external homogeneous
zone and an internal granular zone. Each zone corresponds to
one-half of tbe cells, the clear half being next tbe boundary, and
the granular half being next the lumen of the saccule.

Fig. 6.

a. B.

One saccule of the pancreas of the rabbit in different states of activity. A. After a
period of rest, in which case the outlines of the cells are indistinct, and the inner zone —
i.e., the part of the cells (a) next the lumen (c) — is broad and filled with fine granules
B. After the gland has poured out its secretion, when the cell outlines (d) are clearer,
the granular zone (a) is smaller, and the clear outer zone is wider. (Kuhne and Lea.)

Describe the pancreatic juice.

Pancreatic juice is thick, transparent, odorless, and saltish in
taste. The saltish taste is due to the presence of sodium carbonate ;
if acid be added C02 is liberated. It acts powerfully as a digestive
airent.

What is the appearance of the pancreas when at rest and
at work ?

During digestion it is red and turbid, and at other times pale
and anaemic.

DIGESTION. 67

What is the function of the pancreatic juice ?

It contains at least four hydrolytic ferments, and is, therefore, a
most important digestive fluid.

What are these four pancreatic ferments ?

(1) The diastatle action is caused by a ferment known as amylop-
x'ni, a substance wbich seems to be identical with the ptyalin of
the saliva.

What is the difference between the action of this ferment
and ptyalin on starch ?

It is much more powerful than ptyalin.

(2) The tryptic action, which is caused by the presence of a sub-
stance known as trypsin, or pancreatin, which acts on proteids
converting tbem into peptones, or, as they are sometimes called,
tryptones. Tbe intermediary product between a proteid and a
tryptone is alkali-albumin, corresponding to the acid-albumin of
gastric digestion.

What are leucin and tyrosin ?

Substances normally found in the small intestine produced by a
too prolonged action of trypsin on its self-formed peptone. They
are crystallizable nitrogenous bodies.

What are skatol and indol ?

Strong, stinking decomposition products resulting from the con-
tinuation, pathologically, of this action of trypsin on peptone.

What is the difference in the manner in which trypsin acts
on albuminous matters from that of the gastric
juice?

In gastric digestion fibres of meat swell up before they are
dissolved. In pancreatic digestion they do not swell up but
become eroded.

68 ESSENTIALS OF HUMAN PHYSIOLOGY.

What reaction is necessarily present for the pancreatic
action to take place ?

An alkaline reaction.

What is the alkali commonly present ?

Sodium carbonate, the presence of which is as necessary to tlr
pancreatic action as hydrochloric acid is to the pepcic action.

What two forms of tryptones have we?

One known as anti-peptone, the other as hemi-peptone.

What is the action of the pancreatic juice on fats ?

It first forms them into a fine emulsion, and secondly causes
them to take up a molecule of water and split up into glycerine
and fatty acids. This action of the pancreatic juice is due to the
third ferment, known as steapsin.

According to Kiihne and Roberts the pancreas contains, fourth,
a milk-curdling ferment. The four are, therefore, as follows : ainy-
lopsin, trypsin, steapsin, and the milk-curdling ferment.

At what time is the pancreatic juice poured out ?

On the entrance of food into the small intestine coming from
the stomach.

THE LIVER.

The anatomy of the liver is so closely concerned in its physio-
logical functions that an outline seems unnecessary at this point. It
will be remembered that the liver is made up of many little livers
known as lobes and lobules, each lobule being a perfect gland in
itseif. The bloodvessels are derived from two sources, first, the
venous, which enter by means of the vena porta; and which, branch-

THE LIVER,

69

ing, give off numerous interlobular vessels or veins forming dense
plexuses around the lobules. Branching off from these interlobular
vessels are the capillaries which converge to the centre of the
lobule, forming elongated meshes, between which are rows of cells.

Section of lobule of liver of rabbit in which the blood and bile capillaries hav^' been
Injected (after Cadiat). a. Intralobular vein. b. Interlobular veins, c. Biliary
sanaJa beginning in fine capillaries.

These capillaries on reaching the centre of the lobule form the
intralobular vessel or central vein, which again joins together with

70

ESSENTIALS OF HUMAN PHYSIOLOGY.

others and forms the radicles of the hepatic veins. The second set
of bloodvessels are branches of the hepatic artery which dip down
between the lobules to nourish the whole gland tissue whatever it
may be. The third set of vessels which are present are known as
the bile-ducts, which, arising from the centre of the lobule join
one another and form the interlobular bile ducts, which anastomose
and finally form the common biliary duct.

Fig. 8.

J^#

Section of the liver of the newt, in which the bile ducts have been injected, and can
be seen to form a network of fine capillaries around the liver cells, the outlines and
nuclei of which can be seen.

What is the chemical composition of the liver cells ?

First, proteids or albuminous matters. Second, glycogen, or
animal starch, which is a true carbo-hydrate, and is changed into
sugar by a diastatic ferment.

What conditions influence the quantity of glycogen ?

The eating of large quantities of starch, milk, fruit, or cane-sugar
increases it greatly, while purely albuminous or fatty diets decrease
it greatly.

What are the sources of glycogen ?

It is probably derived from the carbo-hydrates of the food.

THE LIVER. 71

What are the functions of the liver ?

The functions of the liver are three — the secretion of bile, the
formation of glycogen, and the destruction of worn-out blood cells.

What is the use of glycogen in the body ?
It is not really known.

Describe the bile.

Bile is a yellowish-brown or dark green transparent fluid with a
neutral reaction and a bitter taste. Its specific gravity is from 1010
to 1050.

What does bile contain ?

First, mucus, which makes it viscid, and which comes from the
walls of the gall-bladder. Second, the bile acids, glyco-cholic and
tauro-cholic acids, which unite with soda, forming cholates.

Which of the bile acids occur in human bile ?

Both are usually present, though tauro-cholic may be absent.

What is Pettenkofer's test for bile ?

Add concentrated H2S04 drop by drop, then add a ten per cent,
solution of cane-sugar when a reddish purple color is struck.

What is Heintz's test ?

Heintz's test consists in adding nitric acid, when a play of colors
results.

What are the bile pigments ?

Bilirubin, which is yellowish-brown ; biliverdin, which is green ;
bilifuscin, biliprasin, and hydro-bilirubin, the last being the normal
coloring matter of the feces.

What is cholestrin ?

Cholesterin is an univalent alcohol which occurs ill the yolk of
eggs, and in solution in the bile.

Is the secretion of bile a mere filtration of substances already
in the blood ?
No; it is a true secretion, being produced by the cells of the
glauds.

72 ESSENTIALS OF HUMAN PHYSIOLOGY.

What is the quantity of bile secreted per day ?

About seventeen ounces.

What is the difference between the contents of the blood-
stream in the hepatic vein and the portal vein ?

The hepatic vein contains more sugar (?), cholesterin, and blood-
corpuscles, and less albumin, fibrin, free haemoglobin, fats, water,
and salts.

In what way is the coloring matter of the bile obtained ?

By destruction of worn-out blood corpuscles.

What are the functions of the bile ?

The emulsification of the fats, the lubrication of the walls of the
intestine, and to increase the osmotic power of the wall of the gut
in order to facilitate the absorption of fats. It also prevents to a
very considerable extent decomposition and stimulates peristahc
action.

What is the fate of bile in the intestine ?

►Sorne of it passes out with the feces, and part is absorbed and
eliminated as urobilin. The cholesterin is given off with the feces,
and the bile salts are for the most part reabsorbed by the gut.

Have the other juices of the small intestine any digestive
power ?

They probably have some power in the solution of the proteids,
and perhaps a diastatic action.

What is the fate of the salivary, gastric, and pancreatic
ferments ?
Ptyalin is destroyed in the stomach by the acid pepsin, and the
milk-curdling ferment by the alkaline salts of the pancreatic and
intestinal juices and by trypsin, the diastatic ferment of the pan-
creas by acid fermentation in the large intestine.

What is the function of the large intestine ?

It absorbs the liquids from the fecal matter .coming from the
small intestine.

What is the amount of feces in twenty-four hours ?
Six to twenty ounces according to the character of the food.

ABSORPTION.

73

ABSORPTION.

Fig. 9.

Diagram showingthe course of the main trunks of the absorbent system. The lym-
phatlcBof lower extremities, etc., meeting the lacteals of intestines at the receptaculum

chyli (R. C ), which opens into the thoracic duct. The superficial vessels are Bhown in
the diagram on the left arm and leg (S), and the deeper oues on the arm to the right f D).
The glands are here and there shown in groups. The small right duct opens int.) the
veins on the right side. The thoracic duct discharges into the union of the great reins
of the left side of the neck. (Yeo.)

Tlie mucous membrane of the whole alimentary canal is capable of
absorption, some portions more so tha?i others.

Describe the intestinal mucous membrane.

In the mucous membrane are found small glands of two kinds —
the first are Brunner's glands, and are localized in the duodenum,
the others are those of Lieberkiihn, which are distributed over the
entire intestinal tract in great numbers.

74

ESSENTIALS OF HUMAN PHYSIOLOGY.

What is a villus ?

A small process from the wall of the intestine, containing blood-
vessels and a lacteal.

In what two ways does absorption occur ?
By means of the blood-capillaries and the lacteals.

What substances are absorbed by the capillaries and what
by the lacteals ?
The first absorbs sugars and proteids, the lacteals the fats.

Fig. 10.

Drawing of transverse section of duodenum, showing Brunner's glands (B) opening
into Lieberkuhn's follicles (L); V, villi; M, muscular coats. (Yeo.)

What portion of the gastro-intestinal tract carries on the
greatest amount of absorption?
The upper half of the small intestine.

What is the position of the lacteal ?

It lies in the axis of the villus, and is surrounded by a blood-
vessel and a vein. The lacteals anastomose in the sub-adenoid
tissue of the gut, and finally form lymphatic networks which
end in the receptaculum chyli, the beginning of the thoracic
duct which opens into the subclavian vein on the left side near
the junction of the jugular. The villi are possessed of unstriped
muscular fibres, which aid in emptying the lacteal, and the nerves
which supply them are derived from Meissner's plexus.

What three forces are at work in the absorption of digested
food?

Endosmosis, diffusion, and filtration.

ABSORPTION.

75

What do you mean by endosmosis and diffusion ?

Endosinosis is the change which occurs between two fluids which
are capable of forming an intimate mixture with each other through
an animal membrane, but never between two fluids which do not

Fig. 11.

Villus, with capillaries injected, showing their close relation to epithelium, some of the
cells <>f which axe distended with mucus. (Cadiat.)

form a perfect mixture, such as oil and water. Diffusion is tin-
mixing of two liquids placed one over the other in a vessel without
the presence of a septum.

What is the law in regard to the diffusion of crystalloids
and colloids?
Crystalloids will diffuse into colloids, but colloids will not diffuse

76 ESSENTIALS OF HUMAN PHYSIOLOGY.

into crystalloids. Filtration occurs in the small intestine simply
by the pressure which is exerted upon the fluid by the contraction
of the walls, and also by a negative pressure or suction produced
by the villi.

What is the influence of the nervous system on absorption ?

Our knowledge is limited, but it has been found that after extir-
pation of the semilunar ganglion of Budge, or section of the mesen-
teric nerves, the intestinal contents became very fluid, which may
be due to diminished absortion.

ANIMAL HEAT.

What do you mean by the term animal heat?

The temperature at which the body of a warm-blooded animal
is maintained.

What is the normal temperature of man ?
98f ° F.

Is it constant in all persons ?

It varies but a fraction of a degree.

Do all animals have the same temperature as man ?

No ; birds have as high as 107° F., and dogs as high a tempera-
ture as 103° F. In the lower animals the bodily temperature of
members of the same species often varies.

Upon what does the temperature of cold-blooded animals
depend ?
Upon the temperature of the surrounding medium.

What conditions influence bodily temperature ?

Age, sex, period of day, exercise, climate and season ; food and
drink also influence it.

What is the effect of age ?

The temperature of a newborn child is one degree above that
proper to the adult. In full adult life the temperature is lower
than at any other time since it rises again iu old age.

ANIMAL HEAT. 77

What effect has the period of day?

The variation may equal one to one and a half degrees, the mini-
mum late at night or early in the morning; the maximum late in
die afternoon.

What is the effect of exercise ?

It raises the temperature; but physiologists differ as to the actual
amount of increase thus, some state that the rise of temperature
produced by exercise never raises the general bodily temperature
more than about 1° F., while others believe that it raises it much
more. Those who think the actual general rise is slight, believe
that the great rise occurring in tetanus, where all the muscles con-
tract, is due to some other concomitant pathological condition.
Students must be governed in regard to this point by the opinion
of their instructor. Climate and season have very slight influence
over the bodily temperature.

What variations in bodily temperature may we have in
disease ?

In fever we may have a temperature as high as 106° and 110°,
or even 11") F. In Asiatic cholera it sometimes falls to 77° or 79°.

What difference is there in the temperature of different
portions of the body ?

The surfaces of the hands and feet are cooler than any other
portion of the body, while the liver often is as high as 105° F.

From what source is animal heat derived ?

The ultimate source is contained in the potential energy taken
into the body with food and with the oxygen during respiration,"
but the amount of heat formed depends upon the amount of kinetic
energy liberated. The energy of the food stuffs may be called
"latent heat." (For definitions of these terms, see Bodily Me-
tabolism.)

What are the direct sources of heat ?

The blood during digestion becomes laden with more carbon,
hydrogen, and oxygen than is needful for the repair of the ,:-
and these gases uniting with the sulphates develop heat by chemi

78 ESSENTIALS OF HUMAN PHYSIOLOGY.

cal means very rapidly, while the rest of the heat of the body i
more slowly developed by a slower combustion. The brain, the
muscles, and the glands manufacture heat, so that venous blood
leaving one of these parts is warmer than arterial blood.

Is there any difference in the heat-producing properties of
different food stuffs ?
Fat are particularly heating, giving more kinetic energy.

What is the nervous mechanism of animal heat ?

In the brain is seated a heat centre whose function it is to direct
the rapidity of combustion or the development of heat in the body.
Governing this centre are two others, the inhibitory heat centre
(Wood), whose function it is to prevent a too rapid production of
heat, and the accelerator heat centres (Sachs and Aronsohn), whose
function it is to increase the production of heat.

What two functions govern the temperature of the body?

Heat production and heat dissipation. Heat production consists
in the manufacture of a certain number of heat units or calories in
a given space of time in the body, while heat dissipation is the
function by which a certain number of heat units are given off
from the body to the surrounding atmosphere or medium.

What is the effect of increased heat production and de-
creased dissipation?
Increase in temperature, or, in other words, fever.

What is the effect of a decrease in heat production or an
increase in heat dissipation ?
A fall of temperature. Remember that these two functions
balance one another and that disorder of either of them either
raises or lowers bodily temperature.

Under what circumstances is the dissipation of heat in-
creased ?
By cold surroundings, by conditions which bring large quan-
tities of heat to the surface of the body, and by contact of the body
with substances which readily conduct the heat away.

ANIMAL HEAT. 79

What keeps the temperature of the body uniform ?

The circulation of the blood, which distributes the heat very
evenly.

What conditions of the vasomotor system influence the
distribution of heat ?
Local dilatations of the bloodvessels produce increased tempera-
ture of the part and increased heat dissipation, and, indirectly,
increased local heat production.

What is the function of the perspiration in regard to
bodily heat ?
By its evaporation it aids enormously in the dissipation of heat
when heat is formed in or added to the body too rapidly.

Why can a person stand a high heat in a dry atmosphere
better than in a moist atmosphere ?
Because in a dry atmosphere the perspiration is evaporated so
rapidly that the heat is readily dissipated.

How high a temperature may the human being stand in
an absolutely dry atmosphere ?
According to Blagden, a temperature of 198° to 211° F. was
supported in dry air for several moments, and on one occasion he
stood 260° F. for eight minutes, having trained his skin to exces-
sive secretion. Workmen in English iron furnaces sometimes
stand on a furnace floor which is red hot and the air of which
stands at 350° F. Chabert, the so-called "fire-king," is said to
have stood from 400° to 600° F., according to Morrant Baker.

Which one of the animal tissues is the best protector
against cold?

The fatty layer, which nearly always occurs in varying amounts
under the skin in all warm-blooded animals, and forms a protective
covering whereby the conduction of internal heat is almost im-
possible.

Fibrous tissues conduct heat more readily in the direction of
their fibres than at right angles. The bones are the next best con-
ductors of heat, and are followed by blood-clots. The spleen, liver,

80 ESSENTIALS OF HUMAN PHYSIOLOGY.

cartilage, tendon, muscle and elastic tissue, and nails follow as
conductors of heat. The skin is a poor conductor of heat.

What influence has starvation on the bodily temperature 1

It lowers it greatly.

What effect has sleep and hemorrhage on temperature ?

In those persons who sleep during the day and work at night
the typical course of the temperature is inverted from that which
has been already stated as normal. Hemorrhage causes at first a
slight fall in temperature, and after that a rise of several tenths of
a degree, which is curiously usually associated with a chill or slight
rigor. Several days after this the temperature falls again.

What is the cause of the fall of temperature after hemor-
rhage ?
The interference with oxidation.

What effect has the artificial cooling of animals ?

It produces great depression, but voluntary and reflex movements
are not abolished. The pulse falls from 100 to 150 to 20 beats per
minute, the blood pressure falls, the respirations become shallow,
and death occurs with spasms and signs of asphyxia.

What is the asphyxia due to ?

Failure of respiration : for if artificial respiration be employed
at this time the temperature rises fifteen to twenty degrees. Lan-
dois asserted that if in addition to artificial respiration external
warmth be applied, animals apparently dead for forty minutes can
be resuscitated.

What is hibernation ?

A condition in which an animal has all its vital processes
temporarily in abeyance. Respiratory and intestinal movements
cease completely and the cardio-pneumatic movements alone
sustain the slight exchange of oxygen in the lungs. If a warm-
blooded animal be cooled to 30° F., it wakes before freezing.
Varnishing the skin of an animal increases heat dissipation so
enormously that death occurs, which is put aside if external heat
be applied.

THE KIDNEYS. 81

THE KIDNEYS.

What are the kidneys?
Compound tubular glands.

What is the function of the kidneys ?
Their function is the secretion of urine.

What is the purpose of the large amount of fat around
these organs?
It acts as a protective.

What is the size of the adult kidney ?

About four and four-tenths of an inch long, three inches thick,
and two inches wide. In the male it weighs from four to six ounces,
in the female from four to five and a half ounces.

Of what two portions is the kidney made up ?

The parenchyma, consisting of the outer or cortical layer, and
the inner or medullary layer. The medullary layer is also some-
times called the pyramidal portion.

Into what two divisions is the medullary portion divided?
It is subdivided into the boundary layer of Ludwig and the
papillary portion.

What appearance has the cortical portion of the kidney
when torn ?
It presents a granular aspect, due to the presence of the Mal-
pighian corpuscles. Striae are also seen, due to the medullary rays.

What is the difference between the boundary zone or layer

of Ludwig, and the papillary portion of the kidney ?

The boundary zone is darker, and often purplish in color, while

the papillary zone is nearly white, and uniformly striated. The

stria? merge into the apex of the pyramid.

Which is the least pliable, the cortex or medullary portion?
The medulla of the kidney is less pliable than the cortex. This

6

82

ESSENTIALS OF HUMAN PHYSIOLOGY.

is due to the greater amount of connective tissue, and the bundles

of straight tubes which may be traced at regular intervals, running

upward, and becoming smaller and smaller as they pass toward

the periphery.

Fig. 12.

Longitudinal section through the kidney (after Tyson and Henle). 1. Cortex. 1'.
Medullary rays. 1". Labyrinth. 2. Medulla. 2'. Papillary portion of medulla. 2".
Boundary layer of medulla. 3. Transverse section of tubules in the boundary layer.
4. Fat of renal sinus. 5. Artery. * Transverse medullary rays. A. Branch of renal
artery. C. Renal calyx. U Ureter.

In what portion of the kidney is the labyrinth ?

That portion of the cortex which occurs between the medullary
rays is called the labyrinth, owing to the arrangement of its tubules.

THE KIDNEYS. 83

How many pyramids have we in each kidney ?

Usually about eight or twelve. The pyramids are sometimes
called those of Malpighi or Ferrein. The apices of the pyramids
are directed toward the pelvis of the kidney, while their bases
are directed toward the cortex, and each one of them opens into
a small saccule or calyx, which in turn forms with others a dilated
pouch, situated at the pelvis of the kidney, forming the beginning
of the ureter.

How many times do we have the pelvis of the kidney
divided ?
First, into two or three divisions, and then again into eight or
twelve smaller ones, which are called calyces.

What is the function of a calyx ?

It receives the point of one pyramid, generally, but sometimes
two pyramids empty into one calyx.

What do you mean by the tubuli uriniferi ?

Fine, very elongated tubes, composed of a nearly homogeneous
membrane, and lined by epithelium possessing the power of secre-
tion. These tubes are, on the average, one six-hundredth of an
inch in diameter. They begin at the Malpighian corpuscle in the
cortical portion of the kidney, and, after passing through many
convolutions, finally end in the pyramidal bodies, from the papilla-
like point of which the urine drops into the saccules already men-
tioned.

In what portion of the kidney do we find the tubuli
uriniferi ?
Both in the medullary and cortical portions.

Into how many divisions are they divided?
Fifteen.

Is there any difference in the function of each division ?
Certain sections are supposed to secrete certain substances.

What is the glomerulus or Malpighian body ?

It is composed of a small tuft of bloodvessels covered with a

84 ESSENTIALS OF HUMAN PHYSIOLOGY.

layer of cells and surrounded by a membranous covering, known
as Bowman's capsule, which is the beginning or dilated extremity

Fig. 13.

Inner stratum of cortex, without
Malpighian corpuscles.

|e without Malpighian

Subcapsular layer
without Ms
corpuscles.

i Cortex.

Diagram of two uriniferous tubules. (Tyson and Brunton, after Klein and Noble
Smith.) 1. Malpighian tuft surrounded by Bowman's capsule. 2. Constriction, or neck.
3. Proximal convoluted tubule. 4. Spinal tubule. 5. Descending limb of Henle's loop.
6. Henle's loop. 7 and 8. Ascending limb of Henle's loop. 9. Wavy part of ascending
limb of Henle's loop. 10. Irregular tubule. 11. Distal convoluted tubule. 12. First
part of collecting tube. 13 and 14. Straight part of collecting tube. 15. Excretory
ducts of Bellini.

of the uriniferous tubule. They are apparent to the naked eye,
in the cortical portion of the kidney, as little red points. Their
average diameter is xjffth of an inch.

What is the function of the glomerulus or Malpighian
tuft or corpuscles ?
According to most physiologists, the Malpighian tuft secretes the

THE KIDNEYS.

85

liquids and salts of the urine, while the epithelial lining of the
uriniferous tubules secretes urea and uric acid, <>r any substance
which taken into the body is eliminated by the kidneys.

Fig. 14.

Bowman's capsule and glomerulus (after Lanpoik). a. Vas afferens. e. Tas efferons.
c. Capillary network of the cortex, k. Endothelial structure of the capsule, h. Origin
of convoluted tubule.

What peculiar arrangement have we in the blood supply
of the Malpighian tuft ?

The blood passes, by means of the afferent vessel or artery, to the
Malpighian tuft and enters it, giving off immediately a capillary
network. At the other side of this capillary network a vessel
goes off, which, as a general rule, does not leave the Malpighian
body on the opposite side from the entrance of the artery, but finds
its exit from the same opening as that by which the artery entered.
The uriniferous tubule, however, is given off from the Malpighian
body on the opposite side from that at which the artery enters
and the efferent vessel leaves.

The capsule of Bowman, or the beginning of the uriniferous
tubule, may be considered as a sac, into which is secreted the liquid
by the Malpighian tuft.

Is the efferent vessel called a vein ?
The efferent vessel after leaving the Malpighian body forms a

86

ESSENTIALS OF HUMAN PHYSIOLOGY,

second capillary network, twisting around the uriniferous tubules.
Not until these capillaries come together do they form one vessel,
known as the vein.

Why is the efferent vessel smaller than the artery ?

It is somewhat smaller for the reason that it loses some of its
liquid in the Malpighian body.

What other vessels have we ?

Besides the efferent and afferent vessels, we have those known as
the vasa recta, which, instead of being concerned in any way with
the Malpighian tufts, pass directly out of the kidney, through the
medullary portion.

Fig. 15.

Longitudinal section of kidney (after Ludwio and Tyson) PF. Pyramids of Feivein.
RA. Rranch of renal artery. EV. Lumen of renal vein receiving an interlobular vein.
VR. Vasa recta. PA. Apex of a renal papilla, b, b, embrace the bases of the renal
lobules.

THE KIDNEYS. 87

What is their function ?

Their function is to afford a side stream for the blood in cases of
congestion, so that all of it will not of necessity pass to the paren-
chyma of the organ.

What other vessels carry on a side stream ?

Another side stream, which is less important, but for the same
purpose, is produced by the fine interlobular arteries which, as
they approach the surface of the kidney, communicate with the
capillaries of the external capsule.

In what way is the kidney nourished ?

By bloodvessels which dip down from the capsule, and from the
vasa recta.

What are the nerves of the kidney ?

They are derived from the renal plexus and the lesser splanch-
nics.

Do these nerves govern secretion, or only the blood supply?
We know that they govern blood supply, but it is not proven
that they influence secretion.

What effect has increased blood pressure on the urinary
secretion ?
According to most of the text-books, increased blood pressure
increases urinary flow, and vice versa; but recent investigations
have seemed to prove that blood pressure has no very great influ-
ence over the kidney. The urine which is increased by pressure,
contains less solids, proportionately, than urine formed by stimu-
lation. "Pressure" urine is scarcely more than a leakage, and
not a true secretion.

What is the function of the ureters ?

To carry the urine from the pelvis of each kidney to the bladder.

Do the ureters possess any power of urging on the flow ?

Yes; they have a slight peristaltic movement, and are supplied
by motor and sensory nerves, the sensory nerves showing their
presence in the human being when a calculus is being passed.

88 ESSENTIALS OF HUMAN PHYSIOLOGY.

How long does it take the wave of contraction to travel
along the ureters from the kidney to the bladder ?

About one-tenth of a second.

In what way do the ureters enter the bladder ?

Obliquely. They enter the external wall of the bladder at one
point, pass between its coats for a short distance, and then open on
its inner surface.

In what way is this opening arranged ?

A small papilla with a valve-like action, permits the urine to
flow out but not to return, and the oblique manner in which the
ureter enters the bladder forms a sharp bend in that tube which
acts as a valve, particularly when the bladder is distended.

What mechanical arrangement have we to prevent leakage
from the bladder ?

At the neck of the bladder the circular muscular fibres are
strongly developed, and act as a sphincter, and in addition to this
is the muscle known as the sphincter of the urethra, which also
acts in very much the same way. Remember! Both these muscles
must relax before urination can take place.

What is the function of the bladder ?

To retain the urine until a sufficient quantity has been collected
to pass, in order that a constant dribble may not take place.

What is its capacity ?
About one pint.

In what condition is the mucous membrane of the bladder
when the bladder is empty ?
It is thrown into rugous folds.

What is the cause of the movement of the urine ?

First, it is formed under high pressure in the kidney ; second,
gravity, when the person is erect, aids its passage; and, third,
the muscles of the ureter contract rhythmically, and so aid its
onward flow. This movement of the ureter is reflex, and is due to
the presence of the urine in it.

THE KIDNEYS. 89

Do both kidneys act constantly?
No ; they act alternately.

What influence has the ingestion of small or large quanti,
ties of water on the urinary flow ?
During thirst it amounts to but two or three drops every minute,
when drinking it often runs in a steady stream.

In what way is the urine discharged from the bladder ?

By contraction of its muscular coats, which, it will be remem-
bered, run in all directions.

What muscles aid in the voluntary act of urination ?

The respiratory muscles and abdominal muscles. The diaphragm
is fixed, and the act is completed by the accelerator urinie muscle,
which quickens the stream.

In what portion of the spinal cord is the centre for the
bladder ?
In the lumbar region.

What other muscle aids in the expulsion of the last drops
of urine, other than the accelerator urinae ?
The bulbo-cavernosus.

What is the nervous mechanism of urination ?

The sphincter vesicae is kept in a state of contraction by the
motor centre governing it in the cord.

When the urine collects in the bladder a sensory impulse travels
to the cord and brain, and the brain and cord in turn send down
motor impulses which contract the muscular walls of the bladder,
while a second impulse relaxes the sphincters.

Where is the spinal centre for urination situated?

Al>out the point of origin of the third, fourth, and fifth Bacral
nerves.

90 ESSENTIALS OF HUMAN PHYSIOLOGY.

THE URINE.

How much urine is secreted in twenty-four hours ?
About three pints in the normal adult.

At what time of the day does the minimum secretion take
place?
Between 2 and 4 A. M.

At what time of the day does the maximum secretion take
place?
Between 2 and 4 p.m.

What are some of the causes that diminish the quantity
of urine ?
It is diminished by increase in the sweat, diarrhoea, thirst, non-
nitrogenous food, diminution of blood-pressure, and certain dis-
eases.

What are the causes which increase its quantity ?

It is increased by increased blood-pressure, by copious drinking,
by exposure to cold, by the use of nitrogenous food, and various
conditions of the nervous system. Various drugs also influence
the quantity.

What is the specific gravity of the urine?

It varies from 1.005 to 1.015 to 1.025. The minimum specific
gravity occurs after copious drinking and may be 1.002 ; the maxi-
mum after profuse sweating, and may be 1.040. The mean specific
gravity is 1.020.

What ready, but not strictly accurate, method have we

for determining the amount of solids in a given

specimen of urine ?

By the use of Christison's formula, which consists in multiplying

the last two figures of the specific gravity by 2.33, which will give

the amount of solids in one thousand cubic centimetres.

THE URINE. 91

What is the color of the urine due to ?

The color depends on the matters present in it, chiefly UTO-
chronie and urobilin, a derivative of hematin. The color varies
greatly, but the difference in intensity is chiefly governed by the
quantity of water which is present.

What is the cause of the slight cloudiness which appears
in the bottom of a vessel in which urine is placed
for a length of time ?
It is due to mucus, which is chiefly derived from the bladder.

What is the taste and odor of urine ?

Its taste is slightly alkaline or bitter; its odor characteristic and
aromatic. The odor, however, is altered by various causes, par-
ticularly by the administration of drugs.

What is the reaction of the urine "?

It is acid, owing to the presence of acid phosphate of soda.
After standing for a while the acidity is increased, due to fer-
mentation of the mucus and other similar products, and, at the
same time, with this increase in acidity, urates and free uric acid
are deposited.

Under what circumstances outside the body does the
reaction become alkaline ?
After it has become acid it changes to an alkaline reaction, owing
to the presence of ammonium carbonate derived from alterations
of the urea. At the same time, a strong ammoniacal odor ifl
noticeable, and fetor, with deposits of triple phosphates and alkaline
urates, appears.

Does the reaction of the urine vary in different animals ?
In most herbivora it is alkaline and turbid, but this difference
depends not upon a different mode of secretion, but upon the
variety of diet.

Into what three forms is the urine passed at different
times divided ?
Urina potus, urina cibi, and urina sanguinis.

92 ESSENTIALS OP HUMAN PHYSIOLOGY.

What is the difference between each one of these ?

Urina potus is secreted immediately after drinking, urina cibi
after a solid meal, and urina sanguinis is that which is secreted
early in the morning when neither food nor drink has been
ingested.

What is the chief solid of the urine ?

Urea is the chief solid constituent, and it is the most important
ingredient since it is the substance by which the nitrogen of de-
composed tissue is given off.

What is the result when this urea is not freely eliminated
from the body?

It produces the condition known as uraemia, in which the patient
has convulsions and low muttering delirium ending in death.

Does urea exist in a state of solution, or in a solid form
in the urine ?
In a state of solution.

What is its appearance in the solid state?
It forms delicate, silvery acicular crystals.

What is the quantity of urea excreted in twenty-four
hours ?
About five hundred grains.

Is the quantity of urea per day influenced by diet ?

Yes. Nitrogenous or animal foods increase the urea, while a
purely vegetable diet decreases it.

Is there any difference in the amount secreted by males
and females ?

Males secrete more than females, while middle-aged persons
secrete more of it than the very young or old. Remember,
however, that children secrete more in proportion to their weight
than do grown persons.

What is the origin of urea ?

It is derived from two sources : first, portions of unassimilated
elements of nitrogenous food ; second, from the breaking down of
tissue, or tissue waste.

THE URINE. 93

Does urea exist, to a certain extent, preformed in the blood,
or do the kidneys manufacture it from the blood ?
Some of it certainly exists ready formed, the kidneys merely
extracting it.

What is uric acid?

An acid which appears, as a general rule, in small quantities in
the urine of the human being, and which is entirely absent in the
cat tribe. The quantity of it varies greatly in different animals.
In birds and serpents its amount greatly exceeds that of the urea.

In what way is the quantity of uric acid increased?

By nitrogenous food, but decreased by vegetable food. In gout
it is deposited around the joints as the urate of soda.

From what does uric acid arise ?

From the destruction of albuminous matters. The relation
between urea and uric acid is not well understood.

What is hippuric acid ?

It is found in man and is allied to benzoic acid. Benzoic acid
is eliminated as hippuric acid.

What are extractives of the urine ?

They consist of kreatin and kreatinin, two crystallizable sub-
stances derived from muscle metamorphosis.

What are the saline matters of the urine ?

H2S04 in the urine forms a compound chiefly or entirely with
soda or potash, thereby forming salts. The phosphoric acid also
combines and forms salts.

The breaking down of what tissues increases the amount of
phosphates in the urine ?
The nervous tissues.

How are the chlorides formed?

The chlorine combines with ammonia and potash to form chlo-
rides.

94 ESSENTIALS OF HUMAN PHYSIOLOGY.

Do gases exist in large quantities in normal mine?

No; in very small quantities. They are chiefly COa and
nitrogen.

"What pathological conditions of the urine occur ?

Albuminuria is a condition in which a certain amount of albu-
men is allowed to escape from the system by the kidneys. At one
time the presence of albumen in the urine was considered to be
pathognomonic of Bright's disease, but it has been proved that it
may exist physiologically for a short time after the ingestion of
large quantities of albumen. Hematuria is a condition in which
there is blood in the urine, the blood coming from the kidney or
any portion of the urinary apparatus.

What is hemoglobinuria ?

A condition in which free haemoglobin occurs in the urine.
Remember, that haemoglobinuria is not hsematuria.

What is choluria?

The presence of bile in the urine. It occurs in certain condi-
tions in which the circulation of the portal vein is disordered, or
after the ingestion of certain poisons, as, for example, phosphorus.

What is glycosuria ?

Glycosuria is the presence of sugar in the urine. It is termed
diabetes mellitus.

What is the cause of diabetes mellitus?

It is either produced by a lesion occurring in the diabetic centre
in the floor of the fourth ventricle, or is due to disorder of the
circulation of the liver whereby the sugars ingested and manufac-
tured in this organ are improperly distributed.

What is chyluria ?

It is a condition in which the chyle from the digestive tract is
passed out in the urine.

What is diabetes insipidus ?

A condition in which a very large quantity of liquid, of a low
specific gravity and containing no sugar, is passed.

THE SKIN. %

THE SKIN.

What are the chief functions of the skin?

It acts as an external integument for the protection of the
deeper tissues, as a sensitive organ in the exercise of touch, as an
important excretory and absorbing organ, and plays a highly
important part in the regulation of the bodily temperature.

Of what does the skin consist?

The skin consists of a layer of vascular tissue named the corium,
derma, or cutis vera, covered by a layer known as the cuticle or
epidermis. Underneath and within the corium are embedded
several organs with special functions, as follows: the sudoriferous
glands, the sebaceous glands, and the hair follicles, while on its
surface are sensitive papillae.

Are the appendages of the skin, known as the hair and
nails, formed frcm the corium or the epidermis?
They are modifications of the epidermis.

What layer of the epidermis contains the pigment in colored
races ?
The layer known as the rete mucosum.

From what portion of the skin does the papillae arise?
They are conical elevations of the corium or true skin.

What is the function of the papillae ?

Nearly every one of them contains a nerve ending, thereby
increasing the peripheral sensibility. (For the corpuscles of touch,
etc., see the Special Senses, "Touch.")

What is the function of the cuticle ?

It protects the papillse from injury and forms a check on undue
evaporation from the skin. The manner in which it protects
sensibility is made evident when we remember the tenderness of
those areas, where, by constant rubbing, the epidermis is rubbed off.

96 ESSENTIALS OF HUMAN PHYSIOLOGY.

What is the function of the sudoriferous glands ?

They pour out the sweat on the surface of the body through
ducts which at first are spiral but which, as they approach the
surface, become straight.

Are the sudoriferous glands the glands which secrete the
familiar odors in the axilla and elsewhere ?

No ; the glands which are odoriferous are like them save that
they are larger and have very short, straight ducts.

What is the difference between sweat and perspiration?

Sweat is applied to the liquid which is secreted so fast that it
collects in drops; perspiration, to the moisture which is continu-
ously and unconsciously given off by the skin.

What is the function of sweat and perspiration ?

They aid in the dissipation of heat by their evaporation and
thereby reduce the bodily temperature.

How much watery vapor is excreted by the skin in twenty-
four hours?

From one and one-half to two pints.

How much C02 is lost in this manner per day ?

An amount which is almost y^ to ^j of the amount exhaled by
the lungs, and which differs enormously according to the condi-
tions surrounding the individual, and exercise, food, and drink.

What other impurities are given off by the skin other
than C02 ?

Urea and inorganic salts.

Is the excretory function of the skin important ?

Exceedingly so, if interfered with it may produce death by
throwing too great a strain on the kidneys, for remember that the
skin is a supplementary organ to the kidneys.

In what ways may the flow of perspiration be increased
other than by exercise or exposure to heat ?
If a localized vaso-motor palsy occurs sweating sometimes takes

THE SKIN. 97

place ; section of the cervical sympathetic produces copious sweat-
ing of that side of the head.

What are the objects of the sebaceous glands ?

They secrete a lubricating fluid or oily matter which keeps the
skin soft and pliable.

What is the vernix caseosa?

That sebaceous matter which covers the skin during intra-uterine
life.

What is the function of hair?

It acts as a protection from cold, as when on the head, and pro-
tects the skin from friction in the axilla or on the pubis. Besides
protecting the head from changes in temperature, it wards off
blows which might otherwise be serious in their results to the
more vital tissues.

What is the function of the nails ?

To protect the ends of the fingers from injury or the sensory
papilla? of the finger tips from contact with harsh, rough objects,
which, if it occurred constantly, might deprive them of their deli-
cacy of touch.

Can absorption of certain substances take place rapidly-
through the skin?
Very rapidly. A familiar example of this is the ptyalism pro-
duced by mercurial inunctions.

SECRETION.

What is secretion ?

The separation from the blood of some product, directly or indi-
rectly, by the vital process peculiar to a gland or membrane. This
product is called an excretion when it is passed out of the body as
waste, or a secretion when it carries out some function in the animal
economy.

Give a good example of an excreting gland?
The kidney.

98 ESSENTIALS OF HUMAN PHYSIOLOGY.

Give an example of a secreting gland.

The pancreas or mammary gland?

(For the manner in which secretion is carried on in each gland,
see questions on each subject.)

THE MAMMARY GLANDS.

What changes take place in the mammary gland during
gestation ?
It becomes much larger, the areola around the nipple increases
in width and deepens in color, the veins become more prominent,
while the lobules can be plainly felt.

How many lobes has the mammary gland?

From fifteen to twenty, each one of which is divided into several
lobules made up of acini.

What is the function of the lactiferous ducts ?

They carry the secretion to the nipple, on which they open by a
number of orifices. Just before they enter the nipple they dilate,
forming little sacs which collect the milk.

In what way are the fat globules of milk formed ?

They are supposed to be the results of a physiological fatty
degeneration of the cells lining the acini and ducts.
(For Milk, see Articles used as Foods.)

THE BODILY METABOLISM.

What do you mean by the term Bodily Metabolism?

Those phenomena by which all living organisms are capable of
taking substances derived from their food into their tissues, and
making them an integral part of their own bodies ; further than
this, metabolism includes the breaking down of these tissues, and
the removal of the results of their destruction; the first half of the
process is termed assimilation, the second half excretion.

MILK. 99

Does the body merely assimilate sufficient food to replace

exactly those particles which are destroyed, or does

it do more than this, and act as a storehouse, from

which, on a sudden strain, energy may be derived?

It acts as a storehouse of potential energy, which, when necessity

arises, it may transform into kinetic energy.

What do you mean by potential energy?
That energy which possesses the power to move, but is quiescent.

What do you mean by the term kinetic energy?

Potential energy, when exerting its influence, either by pro-
ducing motion or preventing it, is called kinetic energy ; in othei
words, potential energy is latent, kinetic energy is active. A
coiled watch-spring held firmly represents potential energy, but
if the pressure is removed, its force is transformed into kinetic
energy.

GENERAL VIEW OF THE MOST

IMPORTANT SUBSTANCES

USED AS FOOD.

How much of the body is made up of water ?

58.5 per cent, of the body consists of water, which is continually
taken in and given off.

What is the purpose of water in the organism ?

The processes of digestion and absorption require the presence
of water for the solution of the food, and it is also used to carry off
the effete products. So much water exists in the tissues of all
animals that Hoppe-Seyler has put.it that all organisms live in
water.

Milk.

What is the use of milk and its preparations ?

Milk forms a complete typical food, in which are all the con-
stituents necessary for life and growth.

100 ESSENTIALS OF HUMAN PHYSIOLOGY.

What are the constituents of milk ?

In every ten parts of proteids we have ten jjarts of fats and
twenty parts of sugar.

Describe some of the characters of milk.

It is an opaque, bluish-white liquid, with a sweetish taste and a
characteristic odor.

What is this odor due to ?

Probably to the peculiar volatile aromatic substances derived
from the cutaneous secretion of the glands.

What is its specific gravity ?
1.026 to 1.035.

What is the reaction of human milk ?

It is always alkaline ; cows' milk may be alkaline, sometimes
acid, or even neutral. The milk of carnivora is always acid.

What are milk globules ?

Small, highly refractive, oil globules floating in a clear fluid, the
milk plasma. The white color of milk is due to their presence.

Of what do the globules consist ?

Of fat or butter, surrounded by a coating of casein.

What is the effect of churning on these milk globules?

This coating of casein is broken, and the butter globules are
allowed to run together.

What does the milk plasma contain aside from the globules?

It contains free casein, serum-albumin, and, to a less extent, a
body resembling albumin, the lacto-protein of Millon and Lieber-
mann.

What other substances have we in milk ?

Galactin, albuminose, and globulin ; very minute traces of pep-
tone are also present. Milk sugar, a carbohydrate resembling
dextrin, and urea and extractives complete the list of its con-
stituents. Remember, that the casein is the albuminous portion

MILK. 101

of milk while the butter globules make up the hydro-carbon
portion.

When milk is boiled, what changes take place in it ?

The serum-albumin coagulates, while the surface also becomes
covered with a layer of casein which has become insoluble.

Is raw or boiled milk most digestible ?

The raw milk ; if nature had intended that boiled milk should
be more digestible than raw milk, raw milk would have been formed
with the same conditions present that exist in boiled milk.

Upon what does the coagulation of milk depend ?
Upon the coagulation of its casein.

What salt in milk keeps the casein in solution ?

Calcium phosphate; which is, of course, destroyed by the acid
of the stomach. Remember, that milk coagulates in the stomach,
not on account of the acid, but owing to the presence of a milk-
curdling ferment. (See page 63, Digestion.)

What causes the spontaneous coagulation or souring of
milk?
It is produced by the development of lactic acid, which is formed
from the milk sugar by the action of the bacterium lacticum.

What is the difference between human milk and cow's
milk?
It contains less albumin, and the albumin it does contain is
more soluble than that in cow's milk. It also contains more sugar
and fats than does cow's milk.

What is colostrum ?

It is the substance which is secreted at the beginning of lacta-
tion, and contains much serum-albumin, and very litt'.e casein,
while all the other substances, specially the fats, occur in large
amount.

What is the purpose of colostrum?

Containing, as it does, a large amount of fat, it acts as a purga-
tive, and sweeps out the meconium and other effete products from
the alimentary canal of the infant.

102 ESSENTIALS OF HUMAN PHYSIOLOGY.

Are gases found in ordinary milk?
Only in minute traces.

What salts are found in milk?

The potash salts are much more plentiful than the soda salts ;
there is also a large amount of calcium phosphate present.

What is the purpose of the calcium phosphate ?

It is necessary in the formation of the bones of the infant.

What difference is there in the composition of milk at
various times?
That drawn last is always richer in butter, while if the ducts
are emptied frequently the butter decreases but the casein increases.

Are egg-s a typically complete food ?

They are not as complete a food as is milk, but are the most
typical food next to milk.

What is the object attained by cooking flesh?

It breaks up to a certain extent the elastic coverings of the
muscular fibre, softens the connective tissues, and renders it more
tender and easy of digestion.

In the vegetable foods, what are the chief nitrogenous
substances?
Gluten is the most abundant nitrogenous substance present, and
occurs immediately under the husk.

How many groups of foods are necessary for the main-
tenance of health in man?
Five.

What substances make up these groups ?

First, the starches, which are used for the purpose of adding
heat to the body, and also fat ; second, the fats, which are used
for the purpose of maintaining the bodily heat and retaining it;
third, albuminous foods, whose function is to add force to the
system ; fourth, water, which is necessary for the carrying out of
the vital processes ; and fifth, salts, which are also absolutely
needful for the maintenance of health.

MILE. 103

What is the absolute amount of the different food-stuffs
required by an adult in twenty-four hours?
It varies enormously according to the surrounding conditions,
but, as a general rule, it sbould contain 130 grammes of proteids,
84 grammes of fats, and 41)4 grammes of carbohydrate-. Remember,
that the carbohydrates should always be greatly in excess of the
nitrogenous principles.

What effect has the withdrawal of all forms of food-stuffs,
with the exception of one particular class, upon
nutrition ?
The animal wastes, and finally dies with very much the same

symptoms as would follow starvation.

The manner in which effete products art' taken up and excreted
has already been considered (see Circulation, Respiration, and the
Kidney and Urine).

What process goes on during starvation?

All food being taken away from the body the organism is re-
quired to abstract at first the unimportant tissues in order to keep
up its vital processes. After this the wasting becomes marked,
and the bodily weight falls. Weakness, the result of the breaking
down of vital tissues, comes on, and finally death, after all sub-
stances capable of supplying force in the body have been used up,
save those actually concerned in the vital processes.

How long will the average adult survive without food?

About twenty-one to twenty-four days, although cases are on
record of survival for forty-one days.

How much bodily weight is lost before death?
Four-tenths of the bodily weight.

Are fats ever formed from proteids ?

Yes ; as an example of this, the cdw does not consume as much
fat in a day as she gives in butter.

104 ESSENTIALS OF HUMAN PHYSIOLOGY.

THE MUSCLES.1

What is the function of the muscles?

To produce movements, which vary according to the rapidity
and power of their contraction.

In what way do the voluntary muscles act upon the hones ?

As levers. They are often attached to the short arm of the lever,
and while this is apparently a disadvantage, since under these
circumstances greater force is required to lift a given weight, it, in
reality, is of the greatest service, since slight contractions of muscles
cause very extensive and rapid movements of the part.

How many orders of levers are met with in the movements
of the different hones of the skeleton hy the muscles ?

All three; and in some cases all three occur at the same joint.

Give an example of the first order of levers.

When the triceps is the power which draws upon the olecranon,
thus moving the hand and forearm around the trochlea, which acts
as the fulcrum.

Give an example of the second order.

This occurs when the hand, resting on a point of support, acts as
the fulcrum, and the triceps pulling on the olecranon is the power
which raises the humerus, upon which is fixed the body or weight.

Give an example of the third order.

This is exemplified by the action of the biceps in ordinary flexion
of the elbow, in which the biceps is attached to the upper portion
of the forearm.

What two varieties of muscular fibre have we ?

Two ; striped, or striated or voluntary ; unstriped, unstriated or
involuntary. The first group are moved entirely by the will-power,
or by centres under the control of the will-power. The second
group, solely by nervous centres over which the will-power has no
direct influence.

1 The anatomy of muscles is to be found in anatomical text-books.

THE MUSCLES. 105

What large mass of striped muscular fibre is an exception
to this rule?
The heart, which, although it is made up of striped muscle, beats
independently of the will. The arrangement of the heart muscle,
however, is somewhat different from striped muscular fibres else-
where.

What is the difference in the contraction of striped and
unstriped muscular fibre?
The striped muscular fibre usually contracts more rapidly.

What is the consistency of muscle ?

The contractile substance of muscle is so soft as to be almost
fluid, being of the consistency of jelly.

What is the chemical composition of muscle ?

As already pointed out elsewhere, it is impossible to determine
this during life, since the analysis produces death. Muscle, how-
ever, contains the substances known as muscle-serum and muscle-clot
or myosin, which are the result of certain chemical changes occur-
ring after death.

What effect has coagulation of the myosin in muscle ?

Its formation is followed by "rigor mortis," or post-mortem
rigidity.

In what way can this coagulation be postponed?

By keeping the muscle at a temperature but a few degrees above
freezing point. If a muscle be kept in this manner, pressure will
cause the exudation from it of a yellow, opalescent, alkaline juice,
which on still further cooling changes into a jelly.

What effect has warming of this jelly ?

It passes through the stages of coagulation seen in ordinary
muscle after death, producing the same fluid serum and muscle-clot
or myosin.

What is this muscle juice sometimes called ?

Muscle pins) na, which is supposed to be the contractile matter in
living muscle.

106 ESSENTIALS OF HUMAN PHYSIOLOGY.

What does the coagulation of muscle plasma very closely
resemble ?

The coagulation of blood plasma, with the difference that the
muscle clot is gelatinous and not in threads, as is fibrin. It is a
globulin, and is soluble in a two per cent, solution of common salt.
Remember, that this globulin forms the greater portion of albu-
minous matter in muscle.

What is the difference between the reaction of muscles
before and after death ?
Before death they are alkaline ; after death, acid.

Of what does the serum of the muscle consist beside the
albuminous principles ?

1st, kreatin, kreatinin, and xanthin ; 2d, haemoglobin ; 3d, grape
sugar, muscle sugar or inosit, and glycogen ; 4th, sarcolactic acid,
made from the inosit by fermentation ; 5th, carbonic acid ; 6th,
potassium salts ; and, 7th, 75 per cent, of water.

What do you mean by the elasticity of muscle ?

The degree to which the muscle can be stretched and still return
to its normal length. If a given weight be applied to the end of
a muscle, it is stretched a certain distance; but an additional
weight or weights do not produce by any means an elongation
equal to the first. The elongation, on additional strain, is con-
stantly decreased in extent.

Is there any variation in the elasticity of muscles?

At first a strain on a muscle produces very rapid extension ; but
this is constantly decreased as time goes on, finally ceasing.
Muscles which are fatigued are more readily stretched than fresh
ones.

What difference is there between the elasticity of dead
and living muscle ?
Dead muscle possesses less elasticity and requires a greater
weight to stretch it. It can be stretched further than living
muscle, but does not return to its former length as completely as
the normal muscle.

THE MUSCLES. 107

Are the muscles of the body always on the stretch, and if
so, what is the object reached by this condition?
They are always on the stretch, even when passive, and act as
ligaments which hind together, in a compact mass, the entire body.
Muscles nearly always have opposing muscles whose function it is
when exercised, to produce opposite movements. The elasticity
of these muscles, in a passive state, also opposes active contraction
in the opposite muscle, which is, however, easily overcome. After
the active contraction has taken place, the elasticity of the passive
muscle acts as a weak spring, therehy keeping up the tonicity of
the limb and preventing sudden jerkings of the body, as would
occur if a muscle should contract suddenly and " take up the
slack" in the opposite muscle.

What electrical phenomena have we in muscle ?

In the normal living muscle we have invariably present an
electric current known as the natural muscle current.

What circumstances influence this current ?

It is greatly reduced by fatigue and loss of vital power, and is
generally supposed to be absent in perfectly normal passive muscle
lying in situ. As soon as the muscle is moved or disturbed by
partial removal from the body the current develops.

What do you mean by "negative variation" in muscle?

If a muscle be connected with a galvanometer so as to measure
its natural current and then be stimulated to a contraction by
means of the nerve trunks, a marked decrease occurs in the
current. The galvanometric needle swings toward the zero point,
showing that the current is weakened and destroyed. This is
called the negative variation, and precedes the change to an active
condition of the muscle.

What do you mean by the irritability of the muscle ?
The capability with which a muscle passes into contraction.

What are the usual causes of contraction of the voluntary
muscles ?
They contract ordinarily in response to impulses communicated

108 ESSENTIALS OF HUMAN PHYSIOLOGY.

to them by nerves, the impulse originating in the brain or spinal
cord. The will power is the most common cause of contraction
of the skeletal muscles.

What other conditions may produce contractions of the
muscles ?
Contraction of the muscles may be produced either by the appli-
cation to them directly of some irritating or stimulating substance,
or by the application of stimulation to their supplying nerves.

Is it possible to cause contraction in muscular fibre which
is devoid of terminal nerve filaments, or, in other
words, does the contraction of a muscle necessarily
depend upon the presence of peripheral motor
nerves ?
That muscles may be stimulated to contraction without the in-
tervention of nerve fibres, is proved by the fact that some parts
of muscles, as the lower end of the sartorius, respond energetically
to all forms of muscle stimuli, though they possess no nerve
endings ; there are some substances, too, which produce contrac-
tion of muscles on direct application, which will not produce that
contraction when applied to the nerve trunk, as, for example,
ammonia. Again, the muscles will generally respond to various
stimuli long after the nerve supplying them has been killed by
exposure, and curare, which paralyzes the peripheral ends of the
motor nerves in the muscles, in no way prevents the contraction
of the muscle itself when it is directly stimulated.

What forms of muscle stimuli have we ?

First, mechanical stimulation, as by a sudden blow or pinch,
resulting in momentary transient contraction. Second, thermic
stimulation. Contraction of the muscle takes place if the tem-
perature be raised or lowered. This contraction, however, is
scarcely identical with ordinary muscular contractions, since it is
a prolonged spastic contraction of an abnormal type. Third,
chemical stimulation, which may produce contractions by irri-
tating mineral and organic acids, various metallic and neutral
salts. Fourth, electrical stimulation, which is the most common
form employed, and gives the most satisfactory results.

THE MUSCLES.

109

At what time during the application of an electrical current
to a muscle does the contraction take place ?
Remember that it takes place not while the current is passing
through the muscle, but at the moment the current is turned on
or turned off, or is suddenly increased or decreased in strength.
A constant current of exactly even intensity may be made to pass
through a muscle without exciting contraction.

Is the stimulus necessary to produce contraction in a muscle
when applied to its nerve trunk, sufficient to pro-
duce the same degree of contraction in the muscle
when applied to the muscle itself?
No, it is not.

What are the chemical changes resulting in a muscle
during its contraction?
Its neutral or faintly alkaline reaction becomes for the moment
acid, owing to the formation of sarco-lactic acid. More oxygen
is taken up from the blood than when the muscle is at rest. A
greater amount of carbon dioxide is given off, but the change in
the quantity of C02 has no exact relation to the quantity of oxygen
used. A diminution is said to occur in the glycogen of muscle,
and a peculiar muscle sugar makes its appearance.

What changes occur in the elasticity of the muscle during
contraction?
The elasticity is less than when it is in a passive state — that is,
a given weight will stretch a contracted muscle more than a passive
muscle, but the return to the normal length of the muscle is not
so complete, or, in other words, extensibility is increased, elasticity
is decreased.

What effect, therefore, has stimulation of a muscle which

is overloaded by a weight greater than it can lift ?

When stimulation is applied to such a muscle we get elongation

instead of contraction, because of the rule just now given, namely,

that the active state lessens the elastic power of the muscle.

110 ESSENTIALS OF HUMAN PHYSIOLOGY.

What effect has stimulation of one part of a muscle upon
the rest of the muscle ?
A contraction wave passes from the part stimulated over the
whole mass.

What effect has the activity of muscle fibre upon its
temperature ?
It raises it very markedly, the production of heat being in
direct proportion to the tension of the muscle. If the muscle be
kept in a state of constant activity, so that fatigue is produced, the
temperature falls.

What change in shape takes place in the muscle on
contraction?
It shortens, and in direct ratio with its shortening its thickness
increases. There is, therefore, but little change in bulk, but con-
siderable change in shape.

What do you mean by the "latent period" ?

The short space of time which elapses between the moment of
stimulation of a muscle and the beginning of its contraction. In
the voluntary muscle of the frog this lasts only about one-tenth of
a second.

What do you mean by the period of "rising energy"?

The space of time during which contraction occurs first slowly,
then more quickly, then more slowly.

What do you mean by the term "falling energy"?

The period at which relaxation of the muscle takes place. At
first slowly, then more quickly, finally, more slowly.

Is there any pause at the height of contraction before
relaxation begins ?
No, none at all.

Is there any variation in the rapidity of contraction of
different muscles ?
Yes, an enormous difference exists not only in various animals,
but in the same muscles of a single individual. As an example

THE MUSCLES. Ill

of the difference in rapidity of contraction in the muscles of dif-
ferent animals, may be mentioned the fact that while the unstriped
muscular tissue of a mollusc occupies several minutes for its con-
traction, the muscle of the wing of a horse-fly contracts 330 times
a second. The variation and rapidity of contraction differ very
largely with the needs and habits of the animal.

What do you mean by the " maximum contraction " of a
muscle ?
The greatest shortening which can be produced by a single in-
stantaneous impulse or stimulus.

What do you mean by the term " over-maximal contrac-
tion " ?
If the current be increased after the maximum contraction is
reached, a second and still further contraction occurs. This is
called the over-maximal contraction.

What do you mean by the term " summation " ?

If a muscle be caused to contract by a shock of medium strength,
it contracts to its maximum; but if a second shock be given while
the muscle is contracting from the first shock, a new maximum
contraction is added to that already under wray. This is called
the summation of effect.

What do you mean by the " tetanus " ?

A condition of a muscle in which it apparently remains in a
constant state of contraction — or, in other words, a summation of
contractions exists. To produce artificial tetanus, impulse after
impulse must be transmitted to the muscle with great rapidity,
otherwise between each stimulus the muscle will partially relax
or attempt to pass into the condition known as falling energy.

Upon what does the irritability and fatigue of a muscle
depend ?
Upon the amount of labor required and the nourishment supplied
by the blood. Fatigue means lessened irritability.

112 ESSENTIALS OF HUMAN PHYSIOLOGY.

THE NERVOUS SYSTEM.

What is the nerve trunk made up of ?

First, the primitive fibril, which is the simplest form of nerve
filament, and is visible only with a very high power of the micro-
scope.

Is the primitive fibril the same thing as the axis
cylinder ?

No; the axis cylinder is made up of bundles of the primitive
fibrils held together by a slightly granular element.

Give a description of a complete nerve.

It is made up of: 1st. The primitive fibril. 2d. The naked
axial cylinder. 3d. The clothed axis cylinder, covered by the
white substance of Schwann, or the medullary sheath, or the
myelin. 4th. The clothed axis cylinder covered by the sheath of
Schwann, or the neurilemma. 5th. The clothed axis cylinder with
both these coverings, or the complete nerve.

What is the difference between the fibres of the cerebro-
spinal system and those of the sympathetic system ?
Those of the first are formed as the nerves of the 5th group just
given, while the sympathetic are made up of axis cylinders covered
by the sheath of Schwann, or neurilemma, as in the 4th group.

What is the function of Ranvier's nodes ?

They are supposed to permit the diffusion of plasma from outside
into the axis cylinder, and thereby to aid the nutrition of the nerve.

What are the nervi-nervorum ?

They are small nerves which accompany the nerve sheaths,
thereby endowing them with sensibility.

Give some facts in regard to the chemistry of the nervous
substance.
Albumin occurs chiefly in the axis cylinder and in the sub-
stance of the ganglionic cells. Potash, albumin, and a globulin-like
substance are also present. Another substance of the same char-
acter is nuclein, which occurs especially in the gray matter, and
neuro-keratin, a body resembling keratin and which contains
much sulphur. The connective tissue of nerves yields gelatin,
but the sheath of Schwann only yields elastin. In addition to
these we have cerebrin, lecithin, and protagon.

THE NERVOUS SYSTEM. 113

What is the chemical reaction of nervous matter ?

When passive it is neutral or feebly alkaline; while active and
after death it is acid.

What difference is there between the reaction of the ner-
vous matter in general and the reaction of the
brain ?
The gray matter of the brain is supposed to be always acid,

while the other is not.

Have nerves great or slight tensile strength ?

They possess great strength, for it is a well-known fact that in
cases where by accident the arm is torn off, the nerve is the only
part not ruptured. Tillaux has found that the sciatic nerve will
hold a strain of as much as 120 pounds.

What is the function of the nervous system ?

It is the apparatus by which distant parts of the body are kept
in constant relationship with one another so that a change of
condition in any one spot is communicated to, and may set up
corresponding changes in, remote parts.

What two divisions have we of nerve fibres ?

The afferent or centripetal, and the efferent or centrifugal ; most
nerves contain both sets of fibres.

Do nerve fibres possess the power of generating force in
themselves ?
They do not. Neither are they capable of originating impulses.
They are functionally inactive until they receive impulses from
higher nerve centres.

What is the distinction between the white and the gray
nerves ?
The white nerves contain the white substance of Schwann, the
gray nerves do not.

Which of these two varieties is the most common ?

The white by far, since the gray are contained chiefly in the
sympathetic system and parts of the organs of special sense.

8

114 ESSENTIALS OF HUMAN PHYSIOLOGY.

What is the function of an afferent or centripetal nerve ?

To carry impulses from the periphery to the centre which may
receive them.

What is the function of an efferent or centrifugal nerve ?

To carry impulses from the centre to the periphery, which
impulses may arise of themselves in the central nervous system or
be excited reflexly through a sensory nerve.

Are impulses travelling along one nerve trunk ever trans-
ferred to another nerve trunk running near by ?
No, never, under any circumstances, if both nerves are intact.

How many divisions have we of efferent nerves ?

First, motor, or nerves going to muscles causing them to contract;
second, secretory, which call forth the activity of glands ; third,
inhibitory, which check or prevent some activity ; fourth, vaso-
motor nerves, which regulate the contraction of the muscular coat
of the bloodvessels, and trophic, thermic, and electric nerves, all
of which are doubtfully in existence, save the electric, which occur
in animals capable of emitting electrical discharges.

What do you mean by inter-central nerves ?

Inter-central nerves are those which act as bonds of union
between the cells of nerve centres.

What is the velocity of nerve force ?

It is about at the rate of thirty metres per second, or the speed
of a fast express train, so that impulses can only travel from one
portion of a man's body to another at about the same rate as an
express, or about twice as fast as the fastest horse can gallop.

What do you mean by " negative variation " ?

The natural current of a nerve, like that of a muscle, undergoes
a diminution at the moment the nerve is stimulated ; this is termed
the negative variation. The negative variation travels along the
nerve at just the same velocity as the impulse does from the point
of stimulation ; as a consequence of this the negative variation and
nerve impulse are believed to be identical.

THE NERVOUS SYSTEM. 115

What do you mean by electrotonus ?

Electrotonu.s may be defined as the electrical condition of a
nerve, which undergoes constant variation according to the circum-
stances affecting it. This will be more clear after the question on
anelectrotonus and katelectrotonus has been read.

What do you mean by the terms anelectrotonus and
katelectrotonus ?
Anelectrotonus is the term applied to the condition of the nerve
near the anode, or positive pole, during the passage of a constant
electrical current, the irritability of the nerve being decreased in
this region. Katelectrotonus is applied to the part of the nerve near
the cathode, or negative pole, the irritability being here increased.

What do you mean by the irritability of nerves ?

The condition which permits of the transmission of impulses
*rom more or less powerful stimuli.

What conditions are necessary for this irritability ?

A perfect supply of blood, to bring nourishment and carry away
effete matters, an uninjured connection with the nerve centres,
and a normal temperature.

What is the result if the blood supply of a nerve is cut off?
The nerve rapidly loses its excitability, and finally becomes
paralyzed.

Supposing a nerve is exhausted by fatigue or lack of
blood supply, how does recovery occur ?
When a nerve recovers it does so slowly, then more rapidly, and
afterward more slowly.

At what portion of the nerve trunk would you apply the

stimulus to produce the greatest contraction in the

tributary muscle, or, in other words, at what point

would you find the greatest irritability of the nerve?

At some part of the nerve distant from the muscle. The further

from the muscle the more powerful is the contraction produced.

The impulse seems to gather force as it goes along the nerve.

116 ESSENTIALS OF HUMAN PHYSIOLOGY.

What do you mean by the "indifferent point" of a
nerve ?

As already stated, when a constant current is applied to a nerve
its irritability is greater in the neighborhood of the cathode, but is
diminished in the neighborhood of the anode. Near the middle
of the nerve, or rather a point about half way between each pole,
we have an area known as the indifferent point , since at this portion
the increased irritability of the cathode no longer exists, nor does
the diminished irritability of the anode occur. This indifferent
point is not always midway betweeen the two poles, since variations
in the strength of the current influence its position.

What are the laws of contraction 1

1. In all muscles, when the current is broken, the disappearance
of anelectrotonus is the cause of the stimulation. 2. When the
current is made it is the appearance of katelectrotonus which
causes the stimulation. 3. With the same current the contraction
produced with the making of the current is more than the contraction
which occurs on the breaking of the current. 4. Anelectrotonus
causes reduction of irritability and conductivity. 5. Katelectrotonus
causes increase of irritability. 6. With ascending currents, the
portion of the nerve next to the muscle is in a state of reduced
functional activity or anelectrotonus. 7. With descending cur-
rents the part of the nerve next the muscle is in a state of exalted
activity — katelectrotonus. 8. These changes are much weaker with
weak currents than with strong ones.

What do you mean by the term nerve corpuscles or
terminals ?

Those small nerve bodies or corpuscles in which nerve fibres end
and through which efferent nerve fibres give off their impulses
and afferent nerve fibres receive their impulses. Those which are
attached to the endings of sensory or afferent nerves of the skin
are known as tactile corpuscles.

PHYSIOLOGY OF THE SPINAL NERVES. 117

PHYSIOLOGY OF THE SPINAL
NERVES.

It will be remembered that thirty-one pairs of spinal nerves
leave the vertebral canal between the vertebrae, in contradistinc-
tion to the cranial nerves, which come out from the base of the
skull, and that each pair of nerves is attached to the spinal cord
by two roots, known as the anterior and posterior, which becoming
united pass through the intervertebral canal, forming one trunk.
Just before the junction of the two roots it will also be remembered
that the posterior root is enlarged by a ganglionic swelling. The
spinal nerves are, therefore, sometimes called mixed nerves, for the
reason that they contain both efferent and afferent fibres. Those
going from the anterior portion of the spinal cord carry the motor
or efferent impulses, those coming to the posterior part of the
spinal cord carry the afferent impulses.

What do you mean by recurrent sensibility ?

If after division of a motor root the peripheral portion of it be
stimulated some pain is felt. This is due to what is known as
recurrent sensibility, and depends on the fact that some of the fibres
of the sensory root, after having joined the motor root, instead of
going as usual to the periphery, revert and supply the motor root.

What is the function of the ganglia which occur on the
posterior roots of the spinal nerves ?
Their function is not clearly understood. There is no evidence
of their being centres of reflex action, nor can they be shown to
possess any marked automatic activity, but it is supposed that they
preside over the nutrition of the nerve itself, for if the roots be
cut off, that part of the posterior root attached to the cord de-
generates, while the piece attached to the ganglion remains intact.
This is not the case where the anterior or motor root is cut, since
under these circumstances that portion of the nerve next the cord
remains intact, while the divided portion undergoes degeneration.
From this it would appear that the nutrition of the sensory nerves
is governed by the ganglia, while that of the motor nerves is
governed by centres in the cord itself.

118 ESSENTIALS OF HUMAN PHYSIOLOGY.

What is the Ritti-Valli law ?

If a nerve be separated from its centre, or if the centre dies, the
excitability of the nerve is increased ; the increase begins at the
central end and travels toward the periphery — the excitability
then falls rapidly until it disappears entirely.

Do these changes take place more rapidly in the central
or peripheral end ?
They take place more rapidly in the central end. In other
words, the peripheral end remains excitable for a longer time than
the central end.

THE PHYSIOLOGY OF THE CEREBRO-
SPINAL NERVOUS SYSTEM.

The physiology of the cerebro-spinal nervous system includes
that of the spinal cord and the medulla oblongata, the brain, and
the nerves given off from each one of them, and the functions of
the ganglia on those nerves.

What is the function of the membranes of the brain and
spinal cord ?
The dura mater is a tough membrane, and composed of bundles
of connective tissue, whose function it is to enclose, and, to a cer-
tain extent, protect the nervous tissue beneath it. The arachnoid
is a much more delicate membrane, similar in structure to the dura
mater, the function of which is to secrete the cerebro-spinal fluid.
The pia mater consists of immense numbers of bloodvessels, which
dip down and nourish the surface of the brain.

What do you mean by the neuroglia ?

A special form of connective tissue which supports the nerve-
fibres and the cells of the brain and spinal cord.

Of what does the spinal cord consist ?

It is a cylindriform column of nerve-substance connected with
the brain through the medium of the medulla oblongata and pons
Varolii, and terminating in the midst of the roots of the many
nerves which form the cauda equina. It is composed of white and

CEREBRO-SPIN AL NERVOUS SYSTEM. 119

gray nervous matter, of which the white is situated externally and
constitutes the chief portion, while the gray occupies its central
portion, and is so arranged that on the surface of a transverse
section it appears like two somewhat crescentic masses, connected
together by a narrow portion or isthmus.

Is the spinal cord >f the same size throughout its whole
length ?
Nn; it varies greitly. It is very large ic the middle and lower
part of the cervical region and at the lc .vest part of the dorsal
region, since at these two points a large number of nerve fibres are
given off.

Of what does the white substance el the spinal cord consist?
Of nerve fibres with a medullary sheath.

What is the function of these nerve fibres ?
The transference of impulses from cell to cell.

Of what does the gray matter consist ?

Of a dense network of naked nerve fibrils with numerous gan-
glionic cells scattered between them. The nerve fibres in this
substance also transmit impulses from cell to cell.

Does the white or the gray substance contain the ganglionic
cells?
The gray substance.

What are these cells called ?

Multipolar, bipolar, or unipolar cells, for the reason that they
possess processes, one or more in number, which do not divide in
the same way as do the interlaced nerve fibres.

What groups of nerve cells have we in the gray matter ?

1. In the anterior cornua are cells which are the points of origin
for the motor spinal nerves. (See Fig 16.)

2. The tractus intermedio-lateralis, a group of nerve cells mid-
way between the anterior and posterior cornua, near the external
surface of the gray matter. (See Fig. 16.)

3. The posterior vesicular columns of Clarke and Stilling are
found in the posterior cornua near the inner surface. (See Fig. 16.)

120 ESSENTIALS OF HUMAN PHYSIOLOGY".

4. The substantia gelatinosa cinerea of Rolando is scattered
throughout the gray matter, but is chiefly found in the posterior
cornua. (See Fig. 16.)

Fig. 16.

Anterior column, and anterior
radicular zone.

Antero-lateral column.

Posterior column, or
posterior radicular zone.

.Gray substance.

Crossed pyramidal tract.
Cerebellar tract.
Column of Goll.

Column of Burdach.

Transverse section of the spinal cord at level of the upper dorsal vertebrae.
(See scheme below.)

Into how many columns is the spinal cord divided ?

Three on each side. The following scheme will illustrate this
more clearly than words, particularly if the figure is also examined.

1. Anterior columns

2. Posterior columns .

3. Lateral columns

The direct or uncrossed pyramidal tracts, or
column of TUrck, or antero-median column.

The anterior ground bundles, or anterior radi-
cular zones.

Goll's column, or the postero-median column.
Burdach's columns, or the posterior radicular

zones, the posterior lateral columns or the

funiculus cuneatus.

The anterior and lateral mixed paths. ■
The crossed pyramidal paths.
The direct cerebellar paths.

CEREBRO-SPIN'AL NERVOUS SYSTEM

121

Fig. 17.

Fig. 18.

py /mi p/

af &■ ay-

Transverse section of spinal cord of Same, but in dorsal region. (Afrer

monkey ; lumbar region. (After Ferrier.) Ferrier.)

Fig. 19.
J3? PS

Same, but in cervical region. (After Ferrier.)
A, Anterior cornu. P, Posterior cornu. a, Anterior column, I, Lateral column,
p, Posterior column, ac, Anterior commissure, ae, External eel] group9 ; and <n', in-
ternal cell groups, of anterior cornu. a/, Anterior median fissure, or, Anterior roots.
.<:, (Vntral canal, /r, Formatio reticularis i7, Cells of the tractus intermedio-lateralis.
re, Clarke's vesicular column, pc, Posterior commissure, pf, Pesterior median fissure.
/,m. Posterior median column (column of Goll). pr, Posterior roots, tg. Substantlc
gi-latinosa.

122 ESSENTIALS OF HUMAN PHYSIOLOGY.

Give the boundaries of each column.

The anterior column is that tract which lies between the anterior
median fissure and the point of emergence of the anterior nerve
roots ; the lateral column lies between the point of emergence of
the anterior and posterior roots, and the posterior column between
the posterior roots and the posterior fissure.

What are Goll's columns?

The posterior median columns, the functions of which are not
as yet definitely known.

What are Turck's columns ?

The anterior median columns, or the direct pyramidal tracts.
They conduct impulses from the brain in the same manner as do
the lateral columns.

The Functions of the Spinal Cord.

In what manner is conduction carried on by the spinal cord?
It carries the sensory impulses transmitted to it by the sensory
nerves up to the perceptive centres in the brain, and the motor
impulses from the brain down to the nerves which are distributed
to the muscles.

Roughly speaking, what portion of the cord may be con-
sidered motor, and what portion sensory ?
The anterior portion is motor ; the posterior, sensory.

What difference is there in the function of the white and
gray matter ?

According to SchifF, and most physiologists, the gray matter
transmits in all directions both sensory and motor impulses which
are purely reflex in character, or, in other words, only intended to
remain in the cord, while sensory impulses which are to go to the
brain, or motor impulses which pass //-owi the brain, must travel by
the white matter.

It will be remembered that both the anterior motor and the
posterior sensory nerve roots do not arise from the white matter,
but from the horns of the gray.

CEREBRO-SPINAL nervous system. 123

The function of the gray matter in the posterior horns is, there-
fore, limited to the receipt and transmission of sensory impulses
from the periphery to the white matter, which will conduct them
to the brain, or across the cord to a motor cell to complete a reflex
action.1

The function of the gray matter of the anterior horns is limited
to the transmission of motor impulses from the white matter to the
motor nerve trunks, or to the originating of a reflex movement.

What function is supposed to be possessed by the gray
matter around the central canal of the spinal cord ?
To transmit sensory impulses up to the brain without their
having to pass through the white columns.

In what way can you prove, physiologically, that the anterior
columns of the cord are motor and the posterior sensory?
If the posterior columns be destroyed, the foot may be burnt off
but no signs of pain are elicited. If, upon the other hand, the
anterior columns be destroyed, burning of the foot produces
violent pain-cries, but the animal is unable to send the impulse
from the brain to the leg and draw it away from the injury.
Another method is to destroy a motor centre in the brain, and
some time later, the animal being killed, tracts can be traced down-
ward which have undergone sclerosis or atrophy. Similarly tracts
may be traced from the periphery to the centres by destruction or
inflammation of a sensory nerve. This has not yet been found in
he lateral sensory fibres.

What is the function of the direct or uncrossed pyramidal
tracts of the anterior columns and the crossed
pyramidal tracts of the lateral columns ?
They carry all the impulses from the central convolutions of the

cerebrum, by which voluntary movements are executed.

Are the lateral columns solely efferent in function ?

No ; for after destruction of the posterior columns of the cord,
burning of the foot causes signs of pain.

i For definition of a reflex morement, •

124 ESSENTIALS OF HUMAN PHYSIOLOGY.

What is the function of the direct cerebellar paths of the
lateral columns ?
They connect with the cerebellum directly by ascending fibres,
which proceed through the restiform bodies from Clarke's columns
of nerve cells in the gray matter. They connect the posterior nerve
roots of the trunk (not of the extremities) with the cerebellum.

What is the function of the anterior ground bundles of

the anterior columns, and the anterior and lateral

mixed paths of the lateral columns ?

They connect the gray matter of the spinal cord with that of the

medulla, and carry reflex impulses. They also contain those fibres

which are the direct continuation of the anterior spinal nerve

roots which have entered the gray matter. The anterior and

lateral mixed paths of the lateral columns also contain some

sensory paths. This explains how the afferent impulses just spoken

of travel to the medulla.

What is the function of Goll's column ?

It unites the posterior roots with the gray nuclei of the posterior
pyramids, otherwise known as the funiculi gracili, and carries
impulses centripetaUy .

By what is the nutrition of these various conducting paths
governed ?
By nutritive centres, in the case of the centripetal tracts, situated
in the cerebrum. In the centrifugal, or motor, tracts these centres
are situated in the anterior cornua of the cord.

What classification can we make in the function of the
nervous centres in the cord?
Their functions can be divided into conduction, transference, reflec-
tion, and automatism, or the power of originating impulses in them-
selves.

Give an example of conduction through a nerve centre.

If an impulse travels from a peripheral sensory nerve to a single
centre in the spinal cord reflexly it may produce contraction in
the muscles which are tributary to the motor centre next to it.

CEREBRO-SPIN AL NERVOUS SYSTEM. 125

This stimulation, if strong enough, may cause an impulse to travel
to all the other centres in the cord, so that general muscular move-
ments may take place.

Give an example of the transference of nerve force.

The pain in the knee or ankle occurring during hip disease is a
good example of this condition, and is supposed to be due to the
fact that the sensory nerves running from the hip carry impulses
up to the sensory cells in the spinal cord, which again transfer the
sensation they receive to sensory centres in direct communication
with the area of the knee or ankle. Under these circumstances
the brain receives the impulse from the two sets of fibres and mis-
interprets the real cause of the sensory impulse. The impulse,
under these circumstances, may be divided into two portions, the
first of which is the primary, and goes to the brain directly from the
cells in communication with the hip, while the other is the
secondary, and is due to the transference to other centres of the
impulse before it reaches the brain. If the primary and secondary
impulses reach the brain together the pain is referred to both the
hip and knee.

What do you mean by the reflexion of nerve force, or reflex
action ?
Reflex action is due to the fact that an impulse travelling from
the periphery to the body along the sensory nerve reaches the
same point at which a sensory or receptive cell and a motor or ex-
pulsive cell exist side by side. Under these circumstances the
sensory cell transfers an impulse to the motor cell, by conduction,
which in turn starts an impulse down along its tributary motor
nerve, with the result of contraction in the muscle which it supplies.

Give an example of this.

If the foot of a frog be pricked, the leg which is pricked, and to a
certain extent the other leg, are immediately jerked away. That
this jerking away of the leg is not due to the fact that the brain
desires to remove the leg from the irritation, is proved by the fact
that if the spinal cord be cut, thereby preventing any impulses
from reaching the brain, reflex action is as marked as if the cord
was intact.

126 ESSENTIALS OF HUMAN PHYSIOLOGY.

What is Setschenow's reflex inhibitory centre ?

A centre situated in the upper portion of the spinal cord whose
function it is to prevent excessive reflex action. If it were not for
this centre the pricking of a pin would cause but a slight reflex
contraction of the leg, while a violent blow would send such an
impulse to the reflex centres that a severe convulsion or tonic
spasm might result. Under these circumstances, however, the
reflex inhibitory centre controls the motor centres of the spinal
cord and prevents their sending out impulses which would be too
violent.

What is automatism ?

The originating, entirely independent of any external cause, of
an impulse in a nerve cell.

What special centres have we in the spinal cord ?
Centres which govern the bladder and genital organs.

What effect has irritation applied directly to the anterior
and lateral white columns ?
It produces muscular movements but no pain, and they are
consequently excitable but insensible.1

Are the posterior columns, when irritated, sensitive or
insensitive ?
They are very sensitive, particularly near the origin of the
posterior roots.

Is this sensibility due to the presence of sensory nerve
filaments belonging to these columns, or simply to
the presence of the fibres of the posterior roots ?

It is simply due to the fibres of the roots.

What effect has section of the antero-lateral columns ?

It abolishes all power of voluntary movement in the lowc
extremities.

i This has been denied by Van Been and Schiff, but has been proved correct by Ficj,,
Mendelsohn, Ludwig and Woroschilofl, and Horsley.

CEKK BRO-SI'LVAL NERVOUS SYSTEM. 127

What effect has section of the posterior column ?

The power of muscular coordination is lost. It is these columns
which are diseased in locomotor ataxia.

Is the transference of impulses stopped by this ?
No; because of the sensory fibres in the lateral columns.

Does the gray matter respond in any way under the
influence of direct stimulation ?
No, it does not.

What is the result of a lesion of the spinal cord in the
lower part of the sacral region?
There is paralysis of the sphincters of the rectum and bladder
and of the accelerator urinse and the compressor urethral muscles.

What is the result of a lesion high up in the sacral
region ?
Paralysis of the muscles of the bladder, rectum, and anus ; loss
of sensation and motion in the muscles of the leg, except those
supplied by the anterior crural and obturator nerves.

What is the effect of a lesion of the upper part of the
lumbar region ?
Loss of motion and sensation in both legs ; loss of power over
rectum and bladder ; paralysis of the muscles of the abdominal
walls. As a result of this, there is some interference with respira-
tion.

What effect has a lesion of the cervical part of the cord ?
It produces palsy, as do the other lesions named, with, in addi-
tion, paralysis of all the intercostal muscles, and, as a result, great
interference with .respiration. There is paralysis of the muscles
of the upper extremities except those of the shoulders. If a lesion
occurs at the upper cervical region, death is instantaneous from
respiratory failure.

128

ESSENTIALS OF HUMAN PHYSIOLOGY.

The Medulla Oblongata.

The points to be remembered concerning this portion of the nervous
system are as follows :

Its columns are continuous with those of the spinal cord, and
each half of it may be considered to be divided into three columns
or tracts of fibres, in the same manner as they occur in the spinal
cord.

What difference exists between the columns here and in
the cord?
They are more prominent, and separated from each other by
deeper grooves.

What are these columns of the medulla called ?

Pyramids; the anterior columns are called the anterior pyramids,
those of the posterior columns restiform bodies and posterior pyramids.

Fig. 20.

Anterior median fissure.

— Pyramid.

Hypoglossal

Olivary body.

Vagus nerve.

Membrana reti-
culata

Origin of the tri
facial.

Continuation of
cerebellar tracts.

Posterior column

Diagram showing cross section at level of fourth ventricle.

MEDULLA OBLONGATA. 129

What are the direct pyramidal tracts ?

The anterior pyramids which pass directly upward to the cere-
brum without crossing to the other side.

What are the crossed pyramidal tracts?

Those fibres of the lateral columns which cross to the opposite
anterior pyramid.

What is the olivary body ?

On the outer side of each anterior pyramid is a small oval mass
of gray matter, the olivary body.

What is the posterior pyramid ?

A small tract marked off from the posterior part of the restiform
bodies on each side by a slight groove.

What forms the fourth ventricle ?

The restiform bodies diverge, and by so doing lay open a space—
the fourth ventricle.

What is the distribution of the fibres of the medulla
oblongata ?
The anterior pyramids receive fibres from the middle fibres of
the lateral columns of the cord, not only from the same side but
from opposite sides. In other words, some of the lateral fibres of
the left side enter the anterior pyramid of the right side and vice
versa. These are the crossed pyramidal tracts already mentioned.

What is the crossing from one side to the other called ?
Decussation.

After this occurs, what happens next ?

The anterior pyramids with their new fibres pass on upward,
the greater part going through the pons to the cerebrum, while a
smaller part joins some fibres from the olivary body forming the
olivary fasciculus or fillrt. Still another small mass of fibres pro-
ceeds to the cerebellum.

What course do the fibres of the lateral columns pursue ?
The outer fibres go with the restiform tract to the cerebellum,
the middle decussate to the anterior pyramids as al ready stated,

130 ESSENTIALS OF HUMAN PHYSIOLOGY.

and the inner pass on to the cerebrum along the floor of the fourth
ventricle.

What is the direct cerebellar tract ?

The outer fibres of the lateral columns first named.

Do the impulses of the will which arise in the brain pass
down each side of the spinal cord directly and
produce contractions in muscles of the same side ?

No, they do not. The fibres carrying these impulses cross each
other in such a way that impulses arising in the left side of the
brain are made manifest on the right side of the body, while those
arising in the right side of the brain are made manifest in the left
side of the body.

Why is this so ?

The decussation of part of the fibres of the anterior pyramids of
the medulla transfer impulses across the cord.

Does this same transference of impulses take place in the
sensory tract, or, in other words, is a sensation
occurring in the left foot recognized in the right
hemisphere of the brain ?

Yes.

Does the transference take place in the medulla ?

No, it does not. The posterior fibres do not decussate in the
medulla, but Brown-Sequard has shown that the crossing takes
place in the spinal cord.

What effect has section of a lateral half of the spinal
cord?

It produces paralysis of motion on the injured side, but does not
affect sensation in the least on that side. On the uninjured side
motion is preserved but sensation lost.

THE MEDULLA OBLONGATA. 131

Why is this so I

Because, aa has already been stated, the motor impulses are not
transferred in the cord but in the medulla, while sensory impulses
are transferred in the cord.

What is the function of the medulla oblongata ?

In many ways it is similar to that of the spinal cord for it carries
on conduction, transference, reflexion, and automatism. It is in
this portion of the nervous apparatus that the decussation of part
of the fibres of the anterior cornua of the medulla takes place, ex-
plaining the phenomenon which has just been mentioned in regard
to paralysis occurring on the opposite side from the lesion.

What special centres exist in the medulla oblongata ?

First, the respiratory centre^ whose function it is to send out
those impulses which result in respiratory movements, and the
interference with which causes great disorder of respiration or
death ; second, it contains the hypoglossal nuclei for deglutition
which send out the impulses which produce the movements neces-
sary to the acts of swallowing ; third, a centre for the movements
of mastication ; fourth, the chief vaso-motor centre which governs
the bloodvessels all over the body (see Circulation); fifth, the
cardio-inhibitory centre for the regulation of the movements of the
heart through the pneumogastrics ; sixth, the superior cilio-spinal
centres which govern the movements of the iris1 ; seventh, the
inner and outer nuclei of the special sense of hearing ; and eighth,
the glosso-pharyngeal nuclei for the sense of taste; ninth, the
centres for vomiting. The medulla oblongata also gives rise from
its posterior surface and its continuation to the cranial nerves
from the 12th to the 5th inclusive. (See Figs. 21 and 22.)

How do you know that the medulla contains all those
centres which are necessary for the continuance
of life ?
Because the brain and cerebellum can be destroyed and yet the

respiration and heart go on unimpaired.

1 Remember that the inferior cilio-spinal centre acta thus also.

132 ESSENTIALS OF HUMAN PHYSIOLOGY.

Fig. 21.

Diagram of posterior aspect of medulla oblongata showing positions of the nuclei of
the cranial nerves. (After Erb and Ferrier.)

v, Motor nucleus ; v', middle ; and v", inferior sensory nucleus of the fifth nerve ;
vi, abducens nucleus; vn, facial nucleus ; vm, inner, and vm', outer auditory nucleus ;
vm" and vm'", divisions of the anterior auditory nucleus ; ix, glosso-pharyngeal
nucleus; x, vagus nucleus; xi, accessorius nucleus; xii, hypoglossal nucleus; 1,
middle cerebellar peduncle ; 2, superior cerebellar peduncle ; 3, inferior cerebellar
peduncle ; 4, eminentia teres ; 5, stria; acousticse ; 6, ala cinerea.

Diagrammatic representation of the nuclei of the cranial nerves as seen on section.
The left half is supposed to be removed, and the nuclei near the median line are
shaded darker than the others. (After Erb and Ferrier).

Py. Pyramidal tracts. PyKr. Decussation of the pyramids. 0. Olivary body. Os.
Upper olivary body. Roman numbers have same meaning as in other cut. Kz. Clavate
nucleus. Sv. Boots of fifth nerve. Bvi. Roots of sixth, or abducent nerve. Evii.
Roots of facial nerve.

THE MEDULLA OBLONGATA. 133

What is the function of the pons Varolii ?

It contains a large number of nerve fibres both transverse and
longitudinal, and is a conductor of impressions from one part of
the spinal axis to another. Concerning its functions as a nerve
centre little or nothing is certainly known.

What are the functions of the crura cerebri ?

They are formed of nerve fibres, of which the inferior or super-
ficial are continuous with those of the anterior pyramidal tracts of
the medulla, and the superior or deeper fibres with the lateral and
posterior pyramidal tracts, and with the olivary fasciculus. Each
crus cerebri contains among its fibres a mass of gray substance
known as the loci/* niger. They act principally as conducting
organs. As nerve centres they are probably connected with the
functions of the oculo-motor nerves through which are directed
the numerous movements of the eyeball. They are also connected
with the coordination of other movements than those of the eye.

What is the result of injury to the crus cerebri ?

Hither rotatory or disorderly movements, with loss of coordina-
tion, result.

What is the function of the corpora quadrigemina or optic
lobes ?

Removal of those bodies produces total loss of vision ; destruc-
tion of one of them produces blindness in the eye of the opposite
side. It also produces rotatory movements of the body resembling
those occurring after division of the crus cerebri, save that the
movements are slower.

What is the effect of injury to these bodies?

They cannot be said to be the centres of vision, but seem to be
the centres of correlation between retinal impressions and oculo-
motor reactions.

134

ESSENTIALS OF HUMAN PHYSIOLOGY.

What is the function of the corpora striata ?

They are centres of innervation for the same movements as exist
in the cerebral cortex, but of a lower grade of specialization.

Injury to the corpora striata on one side prevents the communi-
cation between the will and the muscles of the opposite half of the
body, so that palsy results, or, in other words, hemiplegia. The
corpus striatum may, therefore, be considered as the motor con-
nection between the cerebrum and the crus cerebri.

Fig. 23.

Diagram of brain and medulla oblongata, a, spinal cord ; 6, b, cerebellum divided,
and above it tbe valve of Vieussens partially divided ; c, corpora quadrigemina ; d, d,
optic thalanii ; e, pineal body; /, /, corpora striata; g, g, cerebral bemispheres in
section ; h, corpus callosum ; i, fornix ; I, I, lateral ventricles ; 3, third ventricle ; 4,
fourth ventricle ; 5, fifth ventricle, bounded on each side by septum luciduni. (Clf.lanb )

What is the function of the optic thalami ?

If the optic thalamus is destroyed on one side sensation of the
opposite side of the body is impaired or lost. It is, therefore,
regarded as the sensory band between the cerebrum and the crus
cerebri.

THE MEDULLA OBLONGATA. 135

What are the functions of the cerebellum ?

It is absolutely insensible to irritation and may be cut away
without any signs of pain; its removal from the body or destruc-
tion by disease is generally unaccompanied by loss or disorder of
sensibility. Animals from which it is removed can see, hear, and
feel pain to all appearance as perfectly as before. It governs the
coordination of movements, and while irritation of the cerebellum
produces no movements at all, remarkable results are produced by
removing part of its substance. As portion after portion of it is
cut away the animal gradually loses the power of springing, walk-
ing, standing, or preserving its equilibrium. If laid upon its back
it cannot recover its normal posture but struggles to get up, and
if a blow is threatened tries to avoid it, but fails to do so.
According to Growers, the middle lobe of the cerebellum governs
equilibrium by means of afferent fibres from the semicircular
canals and the ocular muscles and also the muscles of the legs.

What other function has the cerebellum ?

The middle lobe is also very closely associated with the vagus,
and this is the reason that we are so apt to have vomiting with
vertigo or in cerebellar disease.

What results do we gain, therefore, from these experi-
ments?

We know that the cerebellum has no connection with volition,
sensation, and memory, but merely has the faculty of combining
the action of the muscles and producing thereby the movements
intended by the higher nervous centres. Remember, that the
influence of each half of the cerebellum is directed to the govern-
ment of the opposite side of the bady, and that both halves must
act in unison, or, otherwise, strange disorders of motility result.

What is the mean weight of the brain ?

The mean weight of the brain in man is 1358 grammes, in
woman it is 1220 grammes.

136 ESSENTIALS OF HUMAN PHYSIOLOGY.

What position does the gray matter occupy in regard to
the white ?

The gray matter forms the cortex and is outside the white.

Which is the most vascular ?

The gray matter is much more vascular than the white.

1, 1, Medullary arteries ; and 1', 1", in groups between the convolutions ; 2, 2, arteries
of the cortex cerebri ; a, large-meshed plexus in first layer ; 5, closed plexus in middle
layer ; c. more open plexus in the gray matter next the white substance, with its
vessels (d). (Landois.)

What two varieties of bloodvessels do we have in the
brain ?

The long medullary arteries which, as their name implies, pass
from the pia mater to the white matter through the gray, and the
cortical arteries which in great part enter the gray matter of the
cortex only, although some pass down to the white matter.

THE MEDULLA OBLONGATA. 137

What difference is there between these two sets of arte-
ries ?
The medullary arteries are terminal and do not anastomose,
while the corticals do anastomose and are, therefore, not terminal
arteries.

What is the physiological significance of this ?

A thrombus or embolus in one of the medullary arteries pro-
duces a total starvation of the area supplied by it, but if such an
accident occurs to one of the corticals then the collateral circula-
tion prevents a total cutting off of blood ; therefore, we find that
the most important portion of the cerebrum is supplied in such a
way that it is guarded against accident, while the white matter
which is not nearly so important is unprotected. (See Fig. 24.)

What arrangement of bloodvessels have we for the nutri-
tion of the rest of the brain and the portions of
the nervous apparatus ?
From trunks constituting the circle of Willis branches are given

off which pass upward and enter the brain to supply it with

blood.

Are these arteries terminal, or do they anastomose with
each other?
They are terminals, and do not anastomose.

What is the function of the cerebrum ?

The cerebral hemispheres are the organs by which perception is
carried on and from which motor impulses are given out. They
contain the organ of the will ; they possess memory, or the means
of retaining impressions of sensible influences; and they are the
medium of all the higher emotions and feelings. They carry on
intellection as is evidenced by imagination, understanding, reflec-
tion, and judgment.

How do we know that consciousness depends upon the
action of the cerebral hemispheres ?
If they are injured in any way, consciousness is lost— as, for
example, during an apoplectic fit.

138 ESSENTIALS OF HUMAN" PHYSIOLOGY

How do we know that it is in the cerebral hemispheres
that the intellect is situated ?

Because the higher the intellect is the greater development is
possessed by the brain, and because destruction of the cerebrum
stops intellection. Congenital and other morbid conditions of
the hemispheres always produce disorders of the intellect.

What effect has the extirpation of the cerebrum ?

After the removal of both cerebral hemispheres in animals,
every voluntary impulse, every conscious impression, and every
sensory perception ceases, but the maintenance of the equilibrium
and all the mechanical movements of the body are preserved.

What example of this can you give ?

A frog with its cerebrum removed retains its power of main-
taining its equilibrium. It can sit, spring, or execute complicated
movements which are coordinated, and when it is placed upon its
back immediately turns right side up again.

What is the purpose of the convolutions ?

In order to give a greater surface for the spreading of the cells
in the cortex without making the brain so large that the skull
would be out of proportion to the body.

What do you mean by cerebral localization ?

The determination of the areas in the cerebral hemispheres
governing various portions or functions in the body.

Where is the speech centre located in the cerebrum ?
In the third frontal convolution and the Island of Reil.

On which side of the brain is the speech centre best
developed ?

The left side.

THE MEDULLA OBLONGATA. 139

What are these areas?

The surface of the cerebrum may be divided into three sections
— anterior, middle, and posterior. The anterior lobes contain the
cells for intellection, the middle areas the cells for motion, and

the posterior lobes those for sensation or perception.

As an example of some of the motor centres, give the area
for the arm and leg.
Stimulation of the upper extremity of the ascending parietal
and ascending frontal convolution causes movement of leg, while
stimulation of these two areas lower down causes movements of
the arm.

What is the relative position of the chief centres in the
brain ?

It is a fact that the centres which govern the more massive parts
and which govern the lower regions of the body are high up in
the brain, while the centres for the control of the face and arm,
for example, are lower down on the surface of the cortex.

What portion of the brain perceives pain ?

Horsley has shown that destruction of the gyrus fornicatus
prevents the perception of pain.

In what two ways are these impulses carried to the lower
portions of the nervous system ?
From all this area radiating fibres converge to the base of the-
brain, where some of them pass through the corpora striata and
its three nuclei (the caudate, lenticular, and taeniform), while
others pass through the internal capsule.

What course do these fibres now take ?

After leaving the internal capsule these fibres once more meet
some of those fibres which passed through the nuclei of the cor-
pora striata and form the crustse of the crura cerebri, which con-
tinuing downward through the pons Varolii emerge from its
posterior and lower border in the form of the anterior pyramids
of the medulla oblongata.

140 ESSENTIALS OF HUMAN PHYSIOLOGY.

What course do centripetal impulses take to get to this
portion of the brain ?

When the sensory fibres of the spinal cord reach the medulla
oblongata they pass up on either side of the motor nuclei to form

Fig. 25.

Diagram of some of the paths taken by uerve impulses in the brain and spinal cord.
;. Gray substance of cerebral cortex, c1. Gray substance of cerebellum, cr. Cranial
nerves, some afferent and some efferent. M. Motor (efferent) spinal nerves. S. Sensory
(afferent) spinal nerves. (Yeo.)

the tegmenta, and to become connected with the optic thalami,
corpora geniculata, and corpora quadrigemina. From these
ganglia radiating fibres pass to the receptive areas of the brain.

THE CRANIAL NERVES. 141

THE CRANIAL NERVES.

It will be remembered that, according to most anatomists, the
cranial nerves are divided into twelve pairs.

1. What is the function of the olfactory nerve ?

It is the nerve of special sense by which odors are distinguished;
in other words, it is the nerve of smell. It is distributed to the
mucous membrane of the nose, and arises superficially from the
lower part of the frontal lobe in advance of the anterior perforated
-pace, passing through the cribriform plate of the ethmoid bone.

2. What is the function of the optic nerve ?

It is the nerve of sight, and is distributed to the retina of the
eye. It arises superficially from the geniculate and quadrigeminal
bodies and thalamus, and passes out through the optic foramen of
the orbit. It conveys no other impulses than those of sight.

What is the effect of division of one of the optic nerves ?
It produces complete blindness in the eye of the corresponding
side.

What is the effect of division of the optic tract ?

It produces loss of sight in the outer half of the eye of the same
side, and of the inner half of the eye of the opposite side.

What is the effect of injury to the anterior part of the
optic chiasm ?

It causes blindness in the inner half of both eyes.

3. What is the function of the oculo-motor nerve ?

It is the motor nerve of the levator palpebrarum, the superior,
internal, and inferior rectus, and the inferior oblique muscle of the
eye. Its superficial origin is the inner side of the cerebral crus,
and it finds its exit from the sphenoidal foramen. It also supplies
filaments to the ciliary ganglia from which the ciliary nerves
arise, which enter the eyeball and are distributed to the circular
fibres of the iris and the ciliary muscle. It governs the accommo-
dation of the eye.

142 ESSENTIALS OF HUMAN PHYSIOLOGY.

What effect has stimulation of the oculo-motor on the
pupil ?
It causes contraction of the pupil, internal strabismus, and mus-
cular movements of the eye, but no pain. Section of the nerve is
followed by ptosis, or drooping of the upper eyelid, internal stra-
bismus, due to the supposed action of the external rectus muscle,
and paralysis of the accommodation of the eye.

4. What is the function of the pathetic nerve ?

It governs the movements of the eyeball so far as those are con-
cerned which are produced by the action of the superior oblique
muscle ; it arises from the valve of Vieussens and passes through
the sphenoidal foramen.

5 What is the function of the trifacial nerve ?

It is a nerve of sensation, motion, and taste. It arises from the
side of the pons by a smaller motor and a larger sensory root, and
is divided into three divisions, the first of which supplies the
conjunctiva, the lachrymal gland, the eyeball, the upper eyelid,
the integument of the forehead, and the mucous membrane and
integument of the nose. The second division supplies the lower
lid and conjunctiva, the temple, upper lip, nose, cheeks, and teeth
of the upper jaw. These two divisions are purely sensory. The
third division supplies the muscles and skin of the lower part of
the face, the muscles of mastication, the teeth in the lower jaw, the
tongue, the parotid gland, and the auricle of the ear. This di-
vision contains motor, sensory, and other filaments which carry
the sense of taste.

What is the effect of irritation of the larger root of the
trifacial nerve ?
It produces marked evidence of pain, which is always felt in the
periphery of the nerve, since it will be remembered that pain
arising at the origin of a sensory nerve is always referred to its
peripheral filaments. Irritation of the small root produces move-
ments of the muscles of mastication, whilst section of this root
causes paralysis of these muscles. Section of the large root is

1 For medullary origin of all the rest of the cranial nerves, see page 121.

THE CRANIAL NERVES. 143

followed by a complete abolition of sensibility in the head and
face, but no disturbance of motion.

6. What is the function of the abducent or sixth pair of

nerves ?
Motion, which results in turning the eyeball outward. They
arise from the anterior pyramids, and supply the external rectus
muscle of the eye. Stimulation of this nerve causes outward
rotation of the eyeball, while paralysis of it causes internal stra-
bismus.

7. What is the function of the facial nerve ?

It supplies the motor filaments of the muscles of the ear, scalp,
and face — platysma, digastric, and stylohyoid muscles— and arises
between the olivary and restiform bodies. It finds its exit through
the internal auditory meatus, the facial canal, and the stylo-
mastoid foramen.

What is the peculiarity of the facial nerve?

It is a motor nerve in its origin, but in its course receives sensory
filaments from the fifth pair and the pneumogastric. Irritation of
the facial produces muscular contractions, while division produces
paralysis of the muscles of the face. Remember, that it is this
nerve which gives off the chorda tympani, that branch which
supplies the bloodvessels and secretion of the sublingual and sub-
maxillary glands and the sense of taste in the anterior two-thirds
of the tongue.

8. What is the function of the auditory nerve ?

It governs the sense of hearing, conducting the impulses from
the exterior to the brain. It rises in the floor of the fourth ven-
tricle, and is distributed to the labyrinth of the ear. Destruction
of this nerve produces deafness.

9. What is the function of the glossopharyngeal nerve ?
It governs the sensibility of the pharynx, and therefore influences

taste. It has also motor filaments which pass to the root of the
tongue, the tonsils, the soft palate, the pharynx, and the tympanum.

144 ESSENTIALS OF HUMAN PHYSIOLOGY.

10. "What is the function of the pneumogastric or vagus

nerve ?

It is chiefly made up of sensory filaments which anastomose
with motor filaments from other sources. It influences deglutition,
the action of the heart, the circulatory and respiratory systems,
the voice, and the stomach. It arises from the fore part of the
restiform body and the vagal nucleus of the floor of the fourth
ventricle. The functions of its branches have been considered
when studying the circulation, respiration, etc.

11. What is the function of the spinal accessory nerve ?

It is made up of motor filaments, some of which pass to the
vagus nerve, while others supply the stern o-mastoid and trapezius
muscles. It arises from the lateral columns of the spinal cord and
the gray substance within. It will be remembered that it consists
of two parts, a smaller accessory root whose deep origin is in a
nucleus of gray matter at the back of the medulla below the origin
of the vagus, and a large spinal root from the lateral columns of
the cord.

What is the effect of destruction of its medullary root?

It produces paralysis of the laryngeal muscles, resulting in
aphonia, and impairs the action of the muscles of deglutition.
Irritation of the spinal root produces contractions of the trapezius
and sterno-mastoid muscles, but section of this branch does not
produce absolute palsy in these muscles, since they are supplied
by motor filaments from elsewhere.

12. What is the function of the hypoglossal or sublingual

nerve ?

Its function is motor and it governs all the movements of the
tongue, influences mastication, deglutition, and articulate lauguage.
It rises from the anterior pyramid, the olivary body, and the
hypoglossal neucleus. Irritation of it produces convulsive move-
ments of the tongue, while division of it abolishes all these move-
ments and interferes considerably with deglutition ; articulation
is considerably impaired, and mastication is performed with diffi-
culty from inability to retain the food between the teeth.

THE SPECIAL SENSES. 145

THE SPECIAL SENSES.

What do you mean by the term ' nerves of special sense "1
Those aerves which carry, as do sensory nerves, impulses from

the periphery to those centres in the brain which may perceive
and interpret them, and which differ from the ordinary sensory

nerves in that, as a general rule, the impulses are not the result of
ordinary stimulation by contact, but of one special form of irrita-
tion. As an example of this the optic nerve appreciates light, yet
light can never be said to produce activity of the nervous proto-
plasm by contact; nor do the vibrations of air produced by sound
cause any impulses to travel along any sensory nerves save the
auditory ; neither can we say that the olfactory nerves are stimu-
lated mechanically by the presence of substances so small that
they cannot be distinguished by spectrum analysis, but which,
nevertheless, are perceived by the nostrils ; this is the reason why
each one of the nerves carrying the impressions of sight, smell,
taste, or sound, are called special, since each one of them can
transmit but one variety of impulse.

Do the nerves which carry these impulses of special sense
differ from other nerves in their structure and
ordinary capabilities ?
No; they differ in no way at all from ordinary afferent nerves,

with one or two exceptions.

Is the sensation recognized at the point at which the cause
exists, or by the special centres in the brain ?
It is recognized in the centre, but, as has been stated before,
impulses in sensory nerves are always referred to the periphery,
and, therefore, we are accustomed to say that we feel the burn or
other injury at the spot where it occurs.

By what means is this peculiar condition in regard to
sensation governed ?
It is solely governed by the mind itself, which has been taught
to do this as the result of education, experience, and habit, acquired
by a long series of unconscious experiments in early youth.

10

146 ESSENTIALS OF HUMAN PHYSIOLOGY.

What is necessarily present for a complete special sense
apparatus ?
First, a special nerve ending, only capable of being excited by
special forms of stimuli ; second, an afferent nerve to conduct the
impulse from the special end organ to the nerve centre; third,
nerve cells forming a centre, which is capable of translating the
impulse received into a sensation and of referring that sensation to
some local point ; fourth, associated nerve centres capable of per-
ceiving sensations, forming ideas, and drawing conclusions there-
from, with the object of determining the position, character, and
intensity of the external influence.

The Sensibility of the Skin.

Those impulses which are received through the skin are obtained
through the sense of touch.

Into how many divisions is this sense of touch subdivided?

First, tactile sensibility, by means of which we appreciate the
slightest touch and recognize the exact point at which the skin
receives the impulse. Second, the sense of pressure, by which we are
enabled to judge of the compression which is being exerted on a
certain area ; this sense, however, is by no means so well developed
as the tactile sense. Tlvlrd, the sense of temperature, by which we
are enabled to determine whether an object is hot or cold. This
sense, also, is not perfectly developed, since for a moment we are
unable to determine whether an object is hot or cold unless the
eye or other special sense aids us.

"What is the object of tactile sensibility?

In order that we may judge of the position, character, and shape
of bodies.

Is tactile sensibility exceedingly important to the animal
organism ?
Very important, since without it nothing could be held firmly
in the hand, and all the movements of the body would be seriously
interfered with.

THE SENSE OF TASTE. 1 17

In what way are the nerves arranged for tactile sensi-
bility ?
The sensory nerves running to the skin are endowed with
endings of various forms according to their function ; these forms
are divided into five varieties : First, the touch corpuscles, which
are egg-shaped bodies situated in the papillae of the true skin,
directly under the epithelial cells of the rete mucosum ; they vary
in siz,e c msiderably, according to the amount of work which they
:irc forced to perform; in these the axis-cylinder of the nerve
ends. Second, the end bulbs, which are smaller than the last and
differ from them in that they are only distributed to localized
areas; they are made up of a little vesicle containing fluid in
which the axis-cylinder terminates, the wall of the vesicle joining
the sheath of the nerve. Third, touch ce/ls, which differ from the
others in that they exist in the deeper layer of the epiderm.
Fourth, free nerve endings, which occur on the surface of the epi-
thelium of mucous membranes. Fifth, Pacinian corpuscles, which
are ovoid bodies made up of concentric layers of varying con-
sistence, with a collection of fluid in the centre, in which the axis-
cylinder ends.

The Sense of Taste.

In what way is taste produced ?

By the contact of sapid substances with the endings of the
gustatory nerves of the tongue in the various papillae.

What are these papillae sometimes called ?
"Taste buds" or " taste goblets."

Is it possible to taste a dry substance ?

No; when a dry substance is placed on the tongue the moisture
dissolves or moistens at least some of it.

What proof have we that this is so?

If the tongue be thoroughly dried no taste is perceived.

Where is the chief sense of taste situated ?
In the tongue.

148 ESSENTIALS OF HUMAN PHYSIOLOGY.

What other surfaces aid the tongue in tasting ?

The soft palate and its arches, the uvula, tonsils, and upper
pharynx. The hard palate has little taste power.

What is the nerve supply of the back part of the tongue?

The glosso-pharyngeal.

What is the nerve supply of the tip of the tongue ?
The lingual branch of the trifacial nerve.

What portion of the tongue perceives taste the best ?

The back portion. The tip and middle of the tongue are not so
well endowed with nerves.1 The sense of smell aids the sense of
taste when eating. If the nostrils be closed and the eyes shut no
distinction can be exercised between a piece of apple, potato, or
onion on the tongue.

Do certain areas of the tongue taste certain bodies ?

Yes. The sulphate of quinine is scarcely noticed at the tip, at
the back it is very well perceived. Sugar, on the other hand, is
best tasted on the tip of the tongue.

The Sense of Smell.

How is the sense of smell excited ?

By fine bodies floating in the atmosphere.

What effect on smelling has drying of the nasal mucous
membrane ?

It impairs the power of perceiving odors very greatly.

What is the object of sniffing ?

In order to draw over the nerve endings a current of air con-
taining the odor.

In what way are the olfactory nerves arranged ?

Most of these nerves are distributed to the mucous membrane of
the middle and upper meatus of the nose. The mucous membrane

1 For the muscular movements of the tongue, see Mastication.

THE SENSE OF SIGHT. L49

in this area is not covered by motile cilia such as are found in the
rest of the nasal cavity; it is less vascular and of a peculiar
yellow hue. The extreme delicacy of smell can best be understood
when we remember that Valentin has estimated that two-millionths
of a milligram of musk is sufficient to excite the olfactory nerves
if man. In other animals this sense is even more acute.

The Sense of Sight.

The Eye and its Coverings

What is the function of the eyelids ?

To protect the eyeballs, and to distribute moisture over them
constantly, thereby preventing drying.

How are they formed ?

They are movable folds of skin, each of which is kept in shape
by a thin plate of yellow elastic tissue.

What is the function of the eyelashes ?

To prevent the entrance of foreign bodies, especially when the
lids are half closed.

In what way do they differ from ordinary hairy growths ?

They possess tactile sensibility, which causes, reflex lv, the lids
to close tightly when a foreign body touches them.

What is the purpose of the Meibomian glands along the edges
of the lids?
To lubricate them, and prevent irritation from the tears.

In what portion of the orbit is the lachrymal gland placed ?
In the upper and outer angle.

What is the use of the lachrymal gland ?

To secrete liquid, which will lubricate and keep the eve moist.
When an excessive secretion takes place it runs over the lower
lids, in the form of tears.

On what side of the orbit does the lachrymal secretion escape ?
On the inner side, through thepuncta lachrymalia, one of which

150 ESSENTIALS OF HUMAN PHYSIOLOGY.

exists in each lid ; thence it passes into the lachrymal sac, and
from there through the nasal ducts into the nose.

What function has the lower eyelid which is not possessed
by the upper lid?

It acts as a gutter along which an excess of the tears may flow ;
when one cries the gutter overflows.

What is the function of the orbicularis palpebrarum muscle,
and what is its nerve supply ?

It closes the eye, and is supplied by the facial nerve.

What muscle opens the eye ?

The upper lid is raised by the levator palpebrarum superior,
which is supplied by the o"culo-motor nerve.

In what way does the ending of the optic nerve differ from
any other sensory nerve ?

It is enclosed in a specially arranged organ, the eyeball.

What is the object of the eyeball?

For the purpose of so directing the rays of light that they strike
in a certain way upon the peripheral optic filaments. It also pro-
tects the nerve filaments from all contact with external conditions,
except light.

What is the only stimulus which ordinarily excites the optic
nerve ?

Light.

What is the purpose of the movements of the eyeball?

In order that objects may be brought within the range of vision
without movements of the head.

If electrical, mechanical, or other stimuli be applied to the
optic nerve, what sensations will they produce ?
Light is the only thing appreciated.

What is the function of the sclerotic coat of the eye ?

It gives shape and protection to the organ.

Is the sclerotic coat continuous all over the eyeball?

No, it is not ; for at the anterior portion is a window-like open-
ing, known as the cornea, through which the rays of light pass.

THE SENSE OF SIGHT. 151

What is the function of the cornea ?

It permits light to enter the eye in much the same manner as a
window-pane lets light into a room, and it also effects very mark-
edly refraction of the rays of light.

What peculiar bodies have we in the cornea which move
about ?
The corneal corpuscles, which resemble amoebae in their move-
ments.

Does the cornea possess nerves and bloodvessels ?
Only nerves, which are partly sensory in function.

From what are these nerves derived ?
From the long and short ciliary nerves.

What change takes place in these nerves as they enter the
cornea ?
They enter the cornea as medullated nerve fibres, but the myelin
soon disappears and leaves the naked axis cylinder.

In what way, then, is it nourished ?
By absorption from the bloodvessels at the corneal margin.

What is the function of the choroid coat ?

< hving to its black, pigmented connective tissue cells, it prevents
the transmission of all light from the exterior, save by the corneal
opening, and prevents reflections from side to side. It is this coat
which lacks pigment in albinoes and nocturnal animals, and its
absence prevents good vision in the daytime.

What are the ciliary processes ?

They are highly vascular folds of the choroid, occurring near
the edge of the cornea.

What is the function of the ciliary muscle ?

It attaches the choroid to the sclerotic coat, governs the diametei
and shape of the crystalline lens, and governs accommodation.

152 ESSENTIALS OF HUMAN PHYSIOLOGY.

What is the function of the iris ?

It is a circular membranous diaphragm provided with a central
aperture, the pupil, and regulates the amount of light entering
the eye. It contains two sets of muscular fibres, circular and
radiating.

What are the functions of these two sets of muscular
fibres ?

The radiating fibres dilate the pupil, the circular fibres contract it.

What is the object of this pupillary movement ?
The regulation of the amount of light entering the eye.

Have the vessels of the choroid any intimate connection
with the nutrition of the eye ?

Yes.

Describe these bloodvessels.

The arteries are the short posterior ciliary arteries, which are
about twenty in number and perforate the sclerotic near the optic
nerve. They terminate in the vascular network of the chorio-
capillaris, which reaches as far as the ora serrata. The long posterior
ciliary arteries lie on the nasal and temporal side of the eye; they
run to the ciliary part of the choroid and penetrate the iris, helping
to form the circulus arteriosus iridis major. The anterior ciliary
arteries, which arise from the muscular branches, perforate the
sclerotic coat anteriorly and give branches to the choroid and iris.

What are the veins, and what is their function 1

The anterior ciliary veins receive the blood from the anterior
part of the eyeball and carry it outward ; they do not receive any
blood from the iris.

In what way does the blood from the iris pass out of the
eye?
The venous plexus of the ciliary processes receives the blood
from the iris and passes it backward to the choroidal veins.

THE SENSE OF SIGHT. 153

What arrangement have we on the posterior surface of the
iris to prevent the transmission of light through it?
A layer of dark pigment.

What is the nerve supply of the circular fibres of the iris?
The oculo-motor.

What is the nerve supply of radiating or dilating fibres ?
The trifacial and sympathetic.

Why does the pupil contract when we are looking at near
objects, but dilate for objects which are far away ?
When an object is near, the rays of light are so near together
that they enter through a small opening ; when it is far off the
pupil dilates, in order to let all the rays in that it can to make the
image more distinct.

What is the function of the retina ?

Lying next to the choroid coat the retina is formed by the
expansion of the optic nerve, and it is this membrane which
receives tbe impression of light.

What is the chemical reaction of the retina ?

When fresh it is acid in light, but it is alkaline in darkness.

In what way do the nerve filaments end in the retina ?
In the rods and cones.

Which of these is most highly developed in man ?
The rods.

What do you mean by the blind spot ?

A small point in the retina on which, when light falls, no
impulse is produced ; it is the point of entrance of the optic nerve.

What do you mean by the macula lutea ?

The point at which rays of light produce the greatest visual
impression. It is exactly in the centre of the retina.

154 ESSENTIALS OF HUMAN PHYSIOLOGY.

Are the rods or the cones in greater number here?
The cones.

What is the visual purple ?

A certain purple substance on the retina, which is destroyed by
contact with light. It has been supposed that it aids vision, but
this is apparently contradicted by the fact that it is absent from
the cones and the macula lutea, where vision is best. It can only
be seen by opening an eye in a dark room, and flashing a light
upon it. If the operation be quickly done the image falling on
the retinal pigment may be made permanent by dipping it quickly
in a strong solution of alum.

Does every part of the retina receive all the rays of light ?
No. Each portion receives different colored rays. The periph-
eral portion sees the red rays, etc.

What is the function of the aqueous humor of the eye ?

It affords a medium in which the iris can move. It also supports
the posterior surface of the cornea, and influences the refraction of
light.

What is the function of the vitreous humor ?

It fills out the eyeball and keeps it tense, and aids very largely
in the refraction of the rays of light transmitted to it through the
crystalline lens.

What is the function of the crystalline lens ?

It acts like a strong, magnifying glass, and is biconvex. It is
the most important refracting portion of the eye, and, aided by
other portions of the optical apparatus, directs the rays of light in
such a manner that they fall properly on the retina. It also sepa-
rates the aqueous from the vitreous humor.

In what way are images thrown on the retina ?
They are inverted by the lens, which is biconvex.

Why do we not see objects, therefore, upside down?

Because the brain interprets the inverted image for one in the
proper position.

THE SENSE OF SIGHT. 155

What variation is there in the power of refraction of the
various parts of the lens ?
It increases in density, and consequently in power of refraction,
from without inward.

Give the essential portions of the eye for the carrying out
of its functions, namely, sight.

1. A retina or nervous mass to receive and transmit impulses.

2. Certain refracting media so arranged as to throw the rays of
light in proper form.

.'!. A contractile diaphragm, the iris, which governs quantity of
light admitted.

4. A contractile muscle, the ciliary muscle, to regulate the shape
of the lens and to " accommodate" the eye to distances.

What would be the effect if the retina was exposed to the
light with no refracting media in front of it ?
The perception of light from darkness, but no objects could be
seen.

What do you mean by the terms "refraction and accom-
modation of the eye ? "
By refract io/t we understand that optical adjustment of the eye
which depends upon its anatomical structure; the accommodation
includes those changes of the optical adjustment which are effected
by the ciliary muscle.

When the eye is at rest is it accommodated to near or far
objects?
It is accommodated for the greatest distance.

What do you mean by the " near point? "

The "near point" is the nearest point at which the eye can
clearly perceive an object held before it, as, for example, printed
matter held close to the face.

The "far point" is the same thing reversed, save that the far
point in the human eye is an infinite distance.

By what means do we judge of distance ?
This is largely a matter of education and is unconsciously ob-

156 ESSENTIALS OF HUMAN PHYSIOLOGY.

tained, in the same way as the judgment of size, a mere matter of
practice.

What is chromatic aberration ?

It is the breaking up of ordinary white light into colored rays,
owing to the different colored lights of which ordinary light is
made up. It is due to a defect in the optical apparatus, but in the
normal eye it is diminished by the iris, which cuts off the marginal
rays.

What is spherical aberration ?

It depends upon the fact that luminous rays passing through a
convex lens strike the various parts of the surface at different
angles, and, hence, are differently refracted, the rays striking the
margin of the lens being more bent than those passing through
the centre. Spherical aberration does not, however, cause in-
convenience, since the iris allows only the central rays to pass.

What is astigmatism ?

It consists in an inability to see clearly lines running at certain
angles.

It depends either upon some irregularity in the shape of the
cornea, or in the shape of the lens.

What are entopic images?

Those which depend on the presence of some opacity in the
transparent media of the eye itself. They occur in all eyes to a
a certain extent, and are frequently noticed when one uses the
microscope.

What is the cause of color-blindness ?

The inability of certain areas of the retina to perceive those
rays of light which normally fall on them, owing to the imperfect
development of these areas. The common forms of blindness are
for the red, green, and yellow rays.

What is diplopia ?

Double vision, due to the fact that each eye receives the impulse
at a different time from the other.

THE SENSE OF SIGHT. 157

What is hemianopsia ?

Blindness of one-half of the eye so that objects are split down
the middle and only half of the body perceived. Since the rays
of light cross in the eye, the part of the retina which is blind is
always opposite the object, which cannot be seen. Thus, when the
eye sees no objects to the left of it, it is the right side of the eye
which is blind.

What is myopia?

"Short sightedness." A condition of the eye in which objects
are focussed at a point in front of the retina.

What is hypermetropia?

" Far sightedness." A condition of the eye in which objects are
focussed behind the retina.

What do you mean by presbyopia ?

A state common to old age, due to loss of the power of accom-
modation.

What is an emmetropic eye ?
A normal eye.

Does such an eye as an absolutely normal eye exist ?
Probably not, or in very rare instances.

By what form of glass would you remedy myopia ?
By a concave glass.

By what form of glass would you relieve hypermetropia ?
By a convex glass.

Why do you do this ?

Because in the myopic eye the lens is too convex, while in the
hypermetropic eye it is not convex enough. While this is often
the case, the fault generally depends on a misshapen eyeball.

158 ESSENTIALS OF HUMAN PHYSIOLOGY.

What do you mean by dioptric media ?

Transparent bodies wbicb so refract tbe light that images come
to a focus on the retina.

What do you mean by intraocular pressure?

The tension to which the coats of the eyeball are put by the
varying quantity of the humors of the eye. When the tension is
increased abnormally it is called glaucoma.

What do you mean by the Argyll Robinson pupil ?

An abnormal condition of the pupil in which it does not con-
tract to light, but does contract when accommodation is carried on.

What is nystagmus ?

Gowers think that it is due to faulty fixation of the eyeball by
the reflexes which generally keep it steady. Either the stimula-
tion of the reflexes is insufficient or too great. In albinoes we often
have it because of too much stimulation from light. In children
blind soon after birth it also comes on before the steadying centres
can be developed.

Hearing.

In the same way that all impulses travelling along the optic
nerve are interpreted as light, so are all the impulses travelling
along the auditory nerve interpreted as sound.

Through how many divisions of the ear does the sound

7

Three ; the external ear and auditory canal, the middle ear,
which is shut off from the auditory canal by the tympanic mem-
brane, and the labyrinth .

HEARING. 159

What is the purpose of the external ear ?
To collect sound.

What is the function of the auditory canal ?
By circumscribing the air it increases its vibrations.

What is the function of the cerumen of the external
ear1?
To catch foreign bodies which might otherwise enter.

What is the function of the tympanic membrane ?

It receives the vibrations of the air in the auditory canal, trans-
mitting them to the bones of the middle ear.

For what purpose is the tympanic membrane sloped from
outward inward?

By this means it more readily responds to sounds of varying
character and can be of greater dimensions.

By what means are the vibrations of sound transmitted
after leaving the tympanic membrane ?

Three small bones known as the malleus, incus, and stapes join
together, and reach from the membrane to a secondary membrane
which covers the oval window leading into the vestibule of the
internal ear; the malleus is attached to the tympanic membrane,
while the stapes is in contact with the oval window.

What is the function of the stapedius muscle ?

It is attached to the stapes, and when it contracts pulls that
bone away from the oval window, otherwise a loud sound might
jam the bone into the oval window and produce deafness.

160 ESSENTIALS OF HUMAN PHYSIOLOGY.

What is the function of the tensor tympani muscle?

By drawing the handle of the malleus internally it increases
the tenseness of the tympanic membrane and prevents it from
vibrating too much to sounds of great intensity.

What is the function of the laxator tympani muscle ?

It draws the handle of the malleus outward, and relaxes the
tympanic membrane.

What is the function of the Eustachian tube ?

It communicates with the pharynx and opens into the middle
ear back of the tympanic membrane, affording vent by which,
when the drum is driven in, some of the air may escape. It
equalizes the pressure within and without.

Is the Eustachian tube constantly open?

No, it is not ; if it were, the various sounds in the mouth would
produce sounds in the ear.

In what way is sound transmitted, after passing- through
the ossicles, to the terminal filaments of the audi-
tory nerve ?
Through the semicircular canals and the spiral staircase.

What fills the semicircular canals?

A liquid known as the endolymph.

In what manner does the endolymph receive impulses from
the exterior ?

The endolymph is in direct contact with the membrane which
covers the oval window, and when the stapes strikes against this
membrane it produces vibrations which are taken up by the endo-
lymph.

In what way do the nerves end in the semicircular canals ?
In peculiar epithelioid cells, to which are attached fine hair- like
processes.

What are the functions of the otoliths ?
These small calcareous masses are set in motion by the vibra-

THE VOICE AND SPEECH. 161

tions of the endolymph and come in contact with the endings of
the nerves, producing impulses. The function of those nerve fibres
which run to the cochlea is not clearly understood.

What function have the semicircular canals other than
hearing ?
They appear to govern equilibrium, for if injured the animal
immediately loses its balance. When the horizontal canal is
divided the animal rolls its head from side to side. When one of
the vertical cauals is cut the head moves up and down.

Does section of the semicircular canals destroy the power
of hearing?
No; it influences it very slightly.

What is the function of the organ of Corti?

It is not distinctly known, but it was supposed to be especially
developed in persons with musical tendencies, till it was found
that the pig possessed them in a highly developed state. As
nerve filaments end in these rods, it has been supposed that each
set of rods responds to a certain set of notes.

What differences in sound can the ear distinguish ?

Loudness, pitch, and quality. The judging of the distance from
which a sound is transmitted is purely a matter of training.

The Voice and Speech.

With scarcely any exception all air-breathing vertebrates possess
some arrangement for the production of sound in some part of
the respiratory apparatus. In some animals various modifications
of this sound are produced. In man its modifications are so great
as to permit of speech.

In what way is the voice or sound produced?

By an expiratory blast of air being forced through the narrow
opening at the top of the windpipe, called the glottis. The glottis.
it will be remembered, lies in the lower part of the larynx and is
bounded on each side by thin membranous bands, which, extend-
ing from side to side, vibrate as the air rushes over them. For
this reason, opening of the trachea prevents speech, since all the
air rushes out of the opening rather than over the cords.

162 ESSENTIALS OF HUMAN PHYSIOLOGY.

What are the chief organs of the voice?

The vocal cords. These are governed by the muscles of the
larynx.1

What is the function of the larynx ?

It acts as a cavity in which the vocal cords may produce the
voice.

What is the function of the thyroid and cricoid cartilages?

The function of these two cartilages is chiefly for the purpose of
affording stiff walls around the vocal apparatus for the sake of
protection and attachment. The thyroid cartilage forms an in-
complete ring around the larynx, and covers only the front portion
and sides. The cricoid cartilage, on the other hand, is a complete
ring, the back part of the ring being broader than the front.

What is the function of the arytenoid cartilages ?

They are situated on the top of the back portion of the cricoid
cartilage and are movable upon it, forming a place for the inser-
tion of certain muscles concerned in speech.

What are the intrinsic muscles of the larynx ?

They are those which have a direct action on the vocal cord,
and are nine in number — four pairs and a single muscle: two
crico-thyroids, two thyro-arytenoids, two posterior crico-arytenoids,
two lateral crico-arytenoids, and one arytenoid muscle.

What are the functions of these muscles ?

When the crico-thyroids contract they rotate the cricoid on the
thyroid cartilage in such a manner that the upper and back part
of the former, and of necessity the arytenoid cartilages on the top
of the cricoid cartilage, are tipped backward, while the thyroid is
inclined forward. The result of this is that the vocal cords being
attached in front to the thyroid cartilage and posteriorly to the
cricoid cartilage are put on the stretch. The thyro-arytenoid
muscles have an opposite action, for they pull the thyroid back-
ward and the arytenoid and the upper and back part of the cricoid

1 For the anatomy of the larynx and those portions of the body concerned in speech,
see an anatomical text-book.

THE VOICE AND SPEECH. 163

cartilages forward, thus relaxing the vocal cords. The posterior
crico-arytenoids dilate the glottis and separate the vocal cords by
an action on the arytenoid cartilage. When they contract they

pull together the outer angles of the arytenoid cartilages in such
a manner as to rotate the latter at their joint with the cricoid, and
to throw asunder their anterior angles to which the vocal cords
are attached.

What muscles oppose these posterior crico-arytenoid
muscles?
The lateral crico-arytenoids, which, pulling in the opposite
direction from the other side of the axis of rotation, have, of
course, exactly the opposite effect, and enclose the glottis. The
arytenoid muscle may also close the glottis almost completely, by
pulling together the upper parts of the arytenoid cartilages,
between which it extends.

What is the nervous mechanism of the voice ?

The sensory filaments in the pneumogastric give the glottis that
acute sensibility which prevents the ingress of foreign bodies or
noxious gases into the air-passages. The superior laryngeal
branch of the vagus and the inferior laryngeal branch, or the re-
current nerve, cooperate not only with the pneumogastric in the
closure of the glottis which excludes foreign bodies, but also in
the protection and regulation of the voice. The inferior laryn-
geal nerve governs the contraction of the muscles that vary the
tension of the vocal cords, while the superior laryngeal convey- {•<
the mind the sensations of the state of these muscles, which is
absolutely necessary for their intelligent guidance.

What three properties are possessed by the human voice?
Quality, pitch, and intensity.

Over how wide a musical range does the human voice
extend ?

Including all 4bnns of voice, about three and one-half octaves;
but of this wide range a single individual can rarely sing more
than two octaves.

164 ESSENTIALS OF HUMAN PHYSIOLOGY

What difference exists between the notes of the female
voice and those of the male ?
The lowest note of the female voice is about an octave higher
than the lowest note of the male voice. The highest note of the
female voice is about an octave higher than the highest note of
the male.

In what portion of the vocal apparatus is the variation in
sound produced which results in speech ?
Not in the larynx, but in the mouth and nose, by means of the
teeth, tongue, and lips.

What sound do we have when speech is not accompanied
by the action of the vocal cords ?
Only a whisper.

What effect upon sound has approximation of the vocal
cords ?

The sound emitted is high pitched in character, while non-
approximation of the cords produces sound of greater volume, but
of lower pitch. The pitch does not depend, however, absolutely
on the approximation or non-approximation of the cords, but
more upon the tensity of the cords themselves.

What is the function of the epiglottis in regard to sound ?
When pressed down so as to cover the cavity of the larynx it
serves to render the notes deeper in tone, and, at the same time,
somewhat fuller in quality.

What is aphasia ?

The partial or complete loss of the power of articulate speech
from causes arising in the cerebrum.

What is the difference between aphasia and aphonia ?

Aphasia is the derangement of the mental functions immediately
connected with word-thought, while aphonia is the term applied
to the voicelessness of laryngeal disease.

THE SYMPATHETIC NERVE. 165

What is the term aphaemia applied to?

It is usually used to signify a condition of speechlessness due to
inability to execute the normal movements of the mouth and
tongue. This condition is sometimes called ataxic aphasia.

Does a patient who is aphasic still have the power to
think, and does he still remember words ?
Yes; and he, therefore, can express himself in writing.

What do you mean by the term amnesic aphasia?

It is the condition in which the idea is present but the word is
wanting, although articulation is '' at the service of the word."
The movements in this condition are correct, so far as speech is
concerned, but the patient cannot think of the word to speak it.
This condition is often seen in old persons to a slight extent, and
is called amnesia senilis.

What is paraphasia ?

The inability to connect rightly ideas with the proper words to
express them, so that instead of giving expression to the ideas
the sense may be inverted.

What is agrammatism ?

The inability to form the words grammatically and arrange
them in sentences.

What is bradyphasia ?
A pathological slowness of speech.

The Sympathetic Nerve.

It will be remembered that the sympathetic system contains a
very large number of non-medullated nerve fibres, and consists of
a double gangliated prevertebral cord, one on each side of the
vertebral column.

What are the rami communicantes ?

The nerves given off" by the spinal nerves to the sympathetic
cord. Each spinal nerve does this.

166 ESSENTIALS OF HUMAN PHYSIOLOGY.

What do you mean by the cephalic, dorsal, and abdominal
portions of the sympathetic?
Those portions which govern these areas. In the head the
cephalic portion anastomoses with the cranial nerves to a great
extent. The abdominal portion supplies the abdominal organs.

What are the functions of the sympathetic?

First, the independent functions as represented by the automatic
cardiac ganglia, the mesenteric plexus of the intestine, and the
plexuses of the uterus, Fallopian tubes, ureters, and lymph and
bloodvessels. They are independent in that they are capable of
acting without any impulses from higher centres, but they may
also be governed by the spinal centres under some circumstances.
Second, the dependent functions which are governed by centres, as,
for example, the sensory fibres of the splanchnics.

What is the function of the cervical sympathetic ?

It contains (1) pupil-dilating fibres which, according to Budge,
arise from the spinal cord and run through the upper two dorsal
and lowest cervical nerves into the cervical sympathetic, which
conveys them to the head.

What does the cervical sympathetic also supply ?

(2) Motor fibres for Miiller's smooth muscle of the orbit, and
partly for the external rectus muscle of the eye. It also supplies
(3) vaso-motor branches for the outer ear and the side of the face,
tympanum, iris, choroid, retina in part, the oesophagus, larynx,
thyroid gland, and fibres for the vessels of the brain and its mem-
branes ; (4) secretory and vaso-motor fibres for the salivary glands.
(5) Sweat secretory fibres are given off, as are also secretory fibres
to the (6) lachrymal glands, according to Wolferz and Demtschenko.

What are the functions of the thoracic and abdominal
sympathetic ?
(1) The sympathetic portion of the cardiac plexus, which receives
accelerating fibres for the heart from the lower cervical and first
thoracic ganglion. (2) The cervical sympathetic and the splanch-
nics contain fibres which, when their central ends are stimulated,
excite the cardio-inhibitory centre in the medulla.

GENERATION AND DEVELOPMENT. 167

Give an example of this.

[f an animal be struck sharply on the belly, over tbe Bolar
plexus, death may result from cardiac stoppage due to reflex
inhibition.

What is the splanchnic ?

The splanchnic is a division of the sympathetic, and contains
vaso-motor filaments. All the vaso-motor nerves do not run
through the cord, but some of them leave the cord high up and
pass into the sympathetic. These nerve filaments in the splanch-
nics govern the bloodvessels of the abdomen very largely. The
splanchnic also contains vaso-motor fibres which supply the
kidneys.

What effect has section of the cervical sympathetic, or its
rami communicantes, on the pupil?
It causes contraction of the pupil.

What other effect has section of the cervical sympathetic ?

It causes increased fulness of the bloodvessels on that side, the
eyelids are not held well apart, while the eyeball is sunken and
retracted. Sometimes unilateral atrophy of the face comes on. If
this section be performed in young growing animals, hypertrophy
of that ear and side of face occurs, owing to the increased blood
supply and other trophic changes.

What is the effect of stimulation of the cervical sympa-
thetic ?
It causes dilatation of the pupil, and occasionally hyperidrosis
or profuse sweating of that side of the head. There is also pro-
trusion of the eyeball, and the eyelids are held wide open. The
eyeball, instead of being sunken, as after section, is in a condition
of exophthalmos.

GENERATION AND DEVELOPMENT.

What do you mean by generation and development ?

The first term signifies the original cause of growth, while the
second term signifies the manner of growth after it is once begun.

168 ESSENTIALS OP HUMAN PHYSIOLOGY,

Generative Organs of the Female.

They consist of two ovaries, two Fallopian tubes or oviducts, Vhe
uterus, and a canal known as the vagina.

What is the function of the ovaries ?
The formation of the ova or eggs.

What is the function of the Fallopian tubes or oviducts ?

The conduction of the ova from the ovaries to the uterus.

What is ^he function of the uterus ?

It is a cavity in which, if impregnated, the ovum is retained
until it is fully developed and capable of maintaining its life inde-
pendent of the parent.

What is the function of the vagina?

It is the canal which receives the male generative organ, the
penis, in the act of copulation, and is the passage through which
the foetus is discharged.

Describe the ovaries.

They are two oval bodies situated in the cavity of the pelvis, one
on each side, inclosed in the folds of the broad ligaments. Each
ovary measures about an inch and a half in length and three-
quarters of an inch in width. They are about half an inch in
thickness, and are attached to the uterus by a narrow fibrous cord,
the ligament of the ovary, and more slightly to one of the fimbria?
of the Fallopian tubes. They are enveloped by a dense fibrous
tissue. They are covered on the exterior by the germ epithelium.
The inner substance, or stroma, is a soft fibrous tissue containing,
imbedded in it, a number of vesicles in various stages of develop-
ment.

What are these vesicles called ?
Graafian vesicles.

GENERATION AND DEVELOPMENT. 169

In what way do the Fallopian tubes grasp the ovule when
it is expelled from the ovary?
By means of their fimbriated extremities, which are in constant
ciliary movement.

Describe the formation of the ovule in the ovary.

The vesicles in the stroma gradually approach the surface until
they project above it. Each follicle or vesicle is covered by an
external membranous envelope lined with a layer of nucleated
cells, the membrana granulosa. This follicle contains liquid full of
small microscopic bodies, with the ovule nearly in its centre, unless
the follicle is fully matured when it comes in contact with the
membrana granulosa.

What is the discus proligerus ?

A granular zone of the nucleated cells of the membrana granu-
losa, which is heaped around about the ovule.

What is the size of the human ovule?
About T^jjth of an inch.

What is the zona pellucida or vitelline membrane ?

The investment of the ovule, and it adheres closely to the discus
proligerus.

What lies within the zona pellucida ?

The yelk or vitellus, which is composed of granules and globules
of various sizes.

What arrangement have these globules ?
The largest are at the periphery, the smallest are at the centre.

What does the yelk or vitellus contain?
The germinal vesicle or the vesicula germinativa.

What does this germinal vesicle contain?

At its periphery, at the point nearest the yelk, it contains the
germinal spot or the macula germinativa.

These are all the parts of the Graafian follicle.

170 ESSENTIALS OF HUMAN PHYSIOLOGY.

Does the formation of Graafian follicles go on constantly
during- the child-bearing part of life ?

Yes.

What do you mean by the discharge of the ovule ?

When the follicle is ripe and has reached the surface of the
ovary, the follicular wall becomes thinner and finally bursts. The
ovule and its fluid surroundings escape on the surface of the ovary,
which is grasped by the Fallopian tube, down which the ovule
travels.

Is there any difference in the periodicity of the maturity of
the ovule in the different varieties of animals ?
Yes; in human beings it is once in every twenty-eight days,
while in the common fowl it is constant.

What is the difference between the ovule and the ovum ?

The term ovule is ordinarily applied to the egg previous to
impregnation, while the ovum is the fecundated ovule.

What is menstruation ?

It is regarded by most physiologists as the flow of blood accom-
panying the discharge of a ripened ovule. The rupture of a
follicle is not necessarily accompanied by menstruation, neither is
menstruation necessarily followed by ovulation.

Does rupture of the follicle take place before or after the
flow?

In most cases before or at the beginning ; more rarely at the
middle or end of menstruation.

Describe the menstrual discharge.

It is a thin, sanguinolent fluid having a peculiar odor, and
consists of blood, epithelium, the mucus of the uterus and vagina,
and the remains of the mucous membrane lining the uterus.

What is this mucous membrane called?

The decidua menstruaMs, which is developed to perfection just
before the menstrual flow and then thrown off.

GENERATION AND DEVELOPMENT. 171

Can menstruation be regarded as a hemorrhage ?

No; it can not. It is merely a destructive process whereby the
membrane which was prepared for receiving a fecundated ovule is
thrown off.

At what time of life does menstruation begin and end in
the temperate zone ?
It begins at twelve or fourteen years of age, and ceases at a peril id
between forty and fifty.

Does menstruation ever occur during pregnancy, or in
nursing women?
Rarely ; but such cases are on record.

What is the corpus luteum ?

At the time of rupture of the Graafian vesicle, a yellowish mass,
the corpus luteum, develops itself. It is a round, solid body whose
walls, after the rupture, become covered by small buds of Hesh-
like matter, resembling a granulating wound, and these granula-
tions extend above the ovarian surface. Ultimately they become
covered, but still go on growing inside the ovary. As pregnancy
goes on, the red granulations change to yellow and its consistence
becomes firmer.

Does the corpus luteum depend for its formation on the
effusion of blood which takes place when the
follicle ruptures ?
Not in the least. Remember this. The corpus luteum is, in

reality, a growth of cells from the membrana granulosa.

What difference is there in the growth of the corpus
luteum of pregnancy and in that of ordinary men-
struation?
In pregnancy it remains till gestation is nearly ended. When

impregnation does not occur it shortly disappears.

The Male Sexual Organs.

What is the function of the testicles?
They are the organs which secrete portions of the semen.

172 ESSENTIALS OF HUMAN PHYSIOLOGY.

What other tissues aid in this secretion?

The vesiculae seminales, the prostate gland, and Cowper's glands.

What does the semen consist of?

Of the secretion of all these tissues.

In what way is the secreting- portion of the testicle
arranged?

Into two parts, one of which is the body of the testicle inclosed
within a tough, fibrous membrane, the tunica albuginea, which is
covered externally by a serous membrane, the tunica vaginalis.
The second part is the epididymis and vas deferens.

What is the vas deferens, and what is its function ?

It is the duct of the testicle, about two feet in length. It passes
to the lower part of the epididymis, with which it is continuous,
where it becomes exceedingly tortuous in its course.

Of what does the epididymis consist?

Of a single tube about twenty feet long.

What are the tubuli seminiferi ?
They make up the parenchyma of the organ.

In what way, and from what are the spermatozoids formed?

The seminal tubule is limited by an elastic membrane, the mem-
brana propria, inside of which are several layers of cells, known as
the seminal cells.

How many kinds of seminal cells have we ?

Two. Those resting quietly, others in a state of active division.
The active cells are called the mother cells ; and the smaller cells,
resulting from their division, the daughter cells or spermatoblasts.
The spermatozoids are formed from the spermatoblasts.

What is the appearance of the spermatozoid?

It consists of a small body or head, to which is attached a cilium,
or rapidly moving tail.

GENERATION AND DEVELOPMENT. 173

What is the function of the spermatozoids ?

They are absolutely needful for impregnation, and it is the sper-
matozoids which fecundate the ovule.

How does the semen reach the exterior of the body ?

It is secreted in the tubules of the testicles, then passes along
the vasadeferentia into the vesiculseseminales, and from there into
the urethra.

What is the function of the seminal vesicles other than the
carrying off of the semen?
They secrete some of the liquid in which the spermatozoids float
or swim. This is probably their chief function, at least in some
animals.

What is the function of the prostate and Cowper's glands?
To add the proper liquid to the semen.

Of what, therefore, does semen consist ?

The liquor seminis and the spermatozoids, with detached epi-
thelial cells.

Development.

In what part of the female genital organs does the ovule
become fecundated?
Most commonly in the upper part of the Fallopian tube.

What changes take place in the ovum or the fecundated
ovule ?
The visible change is a slight am<eboid movement of the proto-
plasm of the ovum, which is shortly followed by segmentation,
which consists in the repeated subdivision of the cells present.

How long does this segmentation last ?

It is finished by the time the ovum reaches the uterus.

What is seen in the centre of each segment ?

A central vesicle, which is the result of the repeated division of
another central vesicle, just as the segments themselves are the
result of the division of the yelk itself.

174 ESSENTIALS OF HUMAN" PHYSIOLOGY.

What appearance has the ovum as it enters the uterus ?

Owing to the many segmentations, it is granular, and resembles
a mulberry.

How long a time does the passage of the ovum from the
ovary to the uterus take ?
Probably eight or ten days.

What is the germinal or blastodermic membrane ?

It is a membrane which is formed by the accumulation at the
periphery of the yelk of a number of the segments or cells. Owing
to their number they are pressed against one another, and become
polyhedral in shape.

What are the layers of the blastoderm?

The epiblast, mesoblast, and hypoblast.

What is the function of the epiblast ?

From the epiblast are eventually developed the epidermis and
its various appendages, the cerebro-spinal nerve centres, the sensory
epithelium of the mouth, and the salivary glands.

What are developed from the hypoblast ?

Theepithelum of the whole digestive canal, and the lining of all
the ducts which open into it; the parenchyma of the liver and
pancreas, and the epithelium of the respiratory tract.

What are developed from the mesoblast ?

All the organs not so far mentioned, all the connective tissues,
the muscles, the vascular and genito-urinary apparatus, and the
entire digestive tract, save its lining epithelium.

What is the germinal area ?

The position at which the embryo is about to appear. It is at
first circular, then pyriform.

What is the area pellucida ?

A clear, transparent spot, which develops in the centre of the
germinal area.

GENERATION AND DEVELOPMENT. 175

What is the area opaca?

That portion of the germinal area surrounding the area pellucida.

What is the primitive groove ?

A shallow longitudinal groove which is the first trace of the
embryo. It appears near the back part of the area pellucida.

What is the medullary groove ?

A more permanent groove which soon replaces the primitive
groove. It begins at the anterior part of the area pellucida, ami
gradually displaces the primitive groove.

What are the laminae dorsales ?

Two longitudinal elevations which bound the medullary canal-
They are folds of the epiblast which grow up and extend over and
join each other over the medullary canal, forming it into a closed
canal or tube.

What is this tube now called?
The primitive cerebro-spinal axis.

At what portion of the embryo do the laminae dorsales
first unite ?
About the neck, then the head, and down to the lower ex-
tremity.

What is the notochord or chorda dosalis ?

It is an aggregation of cells from the mesoblast immediately
underneath or back of the medullary canal. It extends nearly the
whole length of the canal, and occupies the future position of the
vertebrae.

What are the protovertebrae ?

Square segments composed of cells from the mesoblast which
appear on each side of the medullary canal along its whole length.

What is the "splitting of the mesoblast"?

Outside of the protovertebrie the mesoblastic cells are split up
into two laminae, known as the parietal and visceral. These Laminae
form the origin for the walls of the trunk. The parietal lamina is
closely connected with the epiblast which adheres closely to the

176 ESSENTIALS OF HUMAN PHYSIOLOGY.

hypoblast, and forms the serous and muscular walls of the alimen-
tary canal and other parts.

What is the somatopleure ?

The united parietal lamina and the epiblast.

What is the splanchnopleure ?

The united visceral layer and the hypoblast.

What eventually becomes of the space between the soma
topleure and the splanchnopleure?
It forms the pericardium, pleurae, and peritoneum.

What are the head and tail folds ?

Those folds of the blastoderm which limit the embryo at the
head and caudal extremities. Similar folds or depressions mark
off the lateral margins of the embryo, which now finds itself entirely
separate from the yelk and surrounded by a clear space.

What is the last portion of the embryo to become com-
pletely separated from the yelk ?
The head and caudal extremity are first separated, but the an-
terior wall of the belly is not closed by the folds till later. Indeed
it is never closed in foetal life, for the umbilicus is the remains of
this connection with the yelk.

What is the neural cavity ?

That cavity formed by the upward growth of the laminee dor-
sales.

What is the body cavity ?

That cavity formed by the downwardly folded blastoderm.

What are the visceral plates 1

The downwardly folded portions of the blastoderm are known as
the visceral plates.

What forms the rudiment of the alimentary canal ?

The folding in of the splanchnopleure lined by hypoblast pinches
off a portion of the yelk-sac inclosing it in the body cavity.

GENERATION AND DEVELOPMENT, 17-

What is the condition of this rudimentary alimentary canal?
It is blind or closed at both ends at this time, while its centre
communicates freely with the cavity of the yelk-sac.

What is the canal called which permits of this communi-
cation ?
The vitelline or omphalo-mesenteric duct. This condition
divides the yelk-sac into two portions.

What is the portion of the yelk-sac outside the body cavity
called ?

The umbilical vesicle.

What is the purpose of the umbilical vesicle ?

It affurds nutriment for the embryo.

In what way does the nutriment reach the embryo?

Through the omphalo-mesenteric vessels which ramify in the
walls of the yelk-sac.

Does this yelk-sac or umbilical vesicle afford food all
through pregnancy for the embryo ?
In mammalia it lasts only for a short time, the nourishment
being derived from the mother.

What is the amnion ?

Beyond the head and tail folds the somatopleure, coated by epi-
blast, rises in folds which grow up and arch over the embryo,
anteriorly, posteriorly, and laterally, all directed toward one point
over the dorsal surface of the embryo.

What is the true amnion?

The inner of the two layers of the somatopleure forms the true
amnion.

What is the false amnion?

The outer layer of the somatopleure.

What is the chorion ?

It is formed by the coalescing of the inner surface of the original

vitelline membrane with the false amnion.

12

1/0 ESSENTIALS OF HUMAN PHYSIOLOGY.

How is the amniotic cavity formed ?

The cavity between the true amnion and the external surface of
the embryo becomes a closed space, which is called the amniotic
cavity.

Does the amnion adhere closely to the embryo ?

No, it gradually is distended with fluid which separates it from
the embryo.

What is this fluid called, and what is its function ?

The liquor amnii, which increases as pregnancy goes on. This
forms a yielding cushion-like support for the embryo, protecting
it from injury and gradually distends the neck of the uterus in
parturition.

What is the allantois ?

It is a highly vascular growth, arising from the hinder portion
of the peritoneal cavity, which gradually pushes its way out
through the amniotic folds, attaching itself to the outer layer of
the amnion (false amnion). In other words, it becomes attached to
the chorion, in mammals in one spot, in birds all over the chorion.

What is formed at this point?

By the interlacing of these vessels with those of the mother the
placenta is developed.

Of what does the chorion now consist ?

Three layers : 1st, the vitelline membrane ; 2d, the outer layer
of the amniotic fold ; 3d, the allantois.

What are the villi of the chorion?

Small processes on its surface which soon become vascular,
particularly so in the region of the future placenta, so as to dip
between the maternal vessels.

What changes take place in the uterine mucous membrane
during this time ?
The follicles become tortuous and enlarged, while the epithe-
lial layers increase in amount.

THE DEVELOPMENT OF ORGANS. 179

What is the result of this increase in the uterine mucous
membrane?
It makes up the membrana decidua.

Into how many divisions are the portions of the membrana
decidua divided?
Three : The fccidua vera, deci'lmi reflexa, and the decidua serotina

What is the function of these three divisions ?

The vera lines the cavity of the uterus; the reflexa grows up
around the ovum and forms an investment for it; while tip
Una becomes especially developed in connection with the villi of
the chorion. Remember, by the third month the vera and reflexa
come in contact, and can no longer be distinguished one from the
other.

What is the function of the placenta ?

It is an organ by which the gaseous and nutritive changes take
place between the maternal tissues and the embryo.

The placenta has, therefore, a foetal part and a maternal part.

THE DEVELOPMENT OF ORGANS.

Vertebral Column and Cranium.

How are the vertebral column and cranium developed?

The notochord or chorda dorsalis consists primarily of soft cellu-
lar cartilage which is gradually inclosed in a membranous sheath,
which after a time becomes fibrous and has transverse annular
fibres. The protovertebrre (see page 1~>4) send processes downward
and inward to surround the notochord, and also upward between
the medullary canal and the epiblast covering it. In the former
situation the cartilaginous bodies of the vertebrae make their ap-
pearance, in the latter their arches which inclose the neural canal.
The vertebrae do not exactly correspond in their position with the
protovertebrre, but each permanent vertebra is developed from the
contiguous halves of the protovertebrae.

The cranium is developed from a prolongation of the vertebral

180 ESSENTIALS OF HUMAN PHYSIOLOGY.

column, and is formed long before the facial bones. It is formed
of one mass, the cerebral capsule, the chorda dorsalis being con-
tinued into its base and ending there with a tapering point.

In what way is the dorsal portion of the body formed ?

The muscles and iutegument of the back, with the exception of
the epiderm, which is developed from the epiblast, are developed
from the musculo-cutaneous plate which is formed by the dorsal
portion of the protovertebrse.

What is developed from the ventral portion of the proto-
vertebrse ?

They give rise to the vertebne and the heads of the ribs, but the
outer part of each protovertebra gives rise to a spinal ganglion and
nerve-root.

What is the condition at this time of the chorda?

It is inclosed in a case, formed by the bodies of the vertebrae, and
gradually wastes and disappears.

How are the body cavities formed?

The dorsal lamince coalesce at the back and complete, by their
union, the spinal canal, and the visceral laminae coalesce anteriorly
and thus form the thoracic and abdominal cavities. An analogous
process occurs in the facial and cervical regions, but the inclosing
laminae are cleft. When these clefts fail to unite in the median
line cleft-palate or harelip results.

Extremities-

In what way are the extremities developed ?

They appear in the form of leaf-like elevations from the parietes
of the trunk at points where more or less of an arch will be pro-
duced for them within.

Heart and Bloodvessels.

How is the heart developed ?

It makes its first appearance as a solid mass of cells of the
splanchnopleure. A cavity is hollowed out of the centre, and

THE DEVELOPMENT OF ORGANS. 181

those detached cells float about in a liquid which boob begins to

move about under the pulsations of the embryonic heart.

How are the bloodvessels developed ?

In the formation of the Large vessels masses of embryonic cells
are arranged in Longitudinal form and hollowed out in much the

same manner as the heart, the cells of the heart cavity and blood-
vessel cavities forming corpuscles. The capillaries seem to be
formed of cells arranged end to end in single line and hollowed
like a pipe-stem.

Nervous System.

How is the nervous system developed ?

All the spinal nerves are derived from the- mesoblast, as are also
the cranial nerves, except the optic and olfactory, which are out-
growths of the anterior cerebral vesicles. The sympathetic system
is also developed from the same mesoblastic layer.

Have the spinal cord and brain the same origin as the
spinal nerves ?
Yes. They arise from the epiblast for the gray matter and for
the white matter.

From what is the spinal cord developed ?

Out of the primitive medullary tube which results from the
folding in of the dorsal laminae.

How is the gray matter formed ?

The tube is narrowed in one diameter so that the canal becomes
narrow and oval in shape, and finally the two opposite sides unite
in the centre of the slit, while the attachments of the two sides at
the top and bottom of the canal decrease in thickness, and finally
separate. The white matter is derived from the surrounding meso-
blasl and grows up around the gray columns. The tissnres are
formed by the separating at the top and bottom of the tube already
described.

What do you mean by the cerebral vesicles ?

A widening out of the medullary canal very early in embryonic
life.

182 ESSENTIALS OF HUMAN PHYSIOLOGY.

How many cerebral vesicles have we?
Three.

What is the purpose of each ?

From the first anterior vesicle are budded off the two primary
optic vesicles, and the rudiments of the hemispheres appear in the
form of two outgrowths at a higher level. The middle vesicle
gives off the rudiments of the corpora quadrigemina, the crura
cerebri, and the aqueduct of Sylvius. The posterior vesicle gives
off the rudiments of the cerebellum, pons Varolii, the medulla
oblongata, and auditory nerve.

Eye.

From what is the eye developed ?

The anterior cerebral vesicle, which sends out a smaller vesicle
on each side, the primary optic vesicles, which are hollow. The
stalks which attach the vesicles to the original vesicle form the
optic nerves. After this the formation of the lens and optic cups, or
secondary optic vesicles, begins.

How is the lens formed ?

By a thickening of the epiblast, which indents the extremity of
the primary optic vesicle and pushes it back till the front wall of
the vesicle is in contact with the posterior wall, and the cavity of
the vesicle is thereby obliterated.

What does this front wall, which has been pushed back,
form ?
The retina.

What does the back wall form?

The pigment layer of the choroid.

The margins of the cups grow up around the lens everywhere
except at the lower part, by the optic nerve, where a fissure
remains.

What is this fissure called ?
The choroidal fissure.

THE DEVELOPMENT OF ORGAN'S 183

What is its purpose ?

Through it the mesoblast, which forms the connective tissue of
the eye, finds an entrance into the cavity of the eye.

Ear.

How is the ear developed ?

Early in embryonic life a depression occurs on each side of the
surface of the head, which is covered by a membrane, the primary
otic vesicle.

What is the purpose of this vesicle?

It develops the membranous labyrinth of the internal ear. The
surrounding mesoblast gives rise to the various bony and carti-
laginous parts inclosing the membranous labyrinth, the bony
semicircular canals, etc. The mesoblast also develops the auditory
nerve.

Nose.

How is the nose developed ?

It originates, like the eyes and ears, in a depression of the
superficial epiblast at each side of the fronto-nasal process, and
these cavities gradually grow hack till they reach the cavity of the
mouth.

Alimentary Canal and Organs.

In what way is the alimentary canal developed ?

It results from the folding in of the splanchnopleure, and is at
first straight and parallel to the vertebral column. It is connected
with the omphalo-mesaraic duct, a point which corresponds with
the lower segment of the ileum, but the duct atrophies and usually
disappears about the fourth month. The attachment is at first
very broad, and only a thin stratum of mesoblast separates the
hypoblast of the canal from the uotochord and proto vertebrae ; but
it subsequently attenuates and becomes the mesentery. In the
fourth month the part connected with the umbilical vesicle loops
forward. The part above the umbilical opening becomes the

184 ESSENTIALS OF HUMAN PHYSIOLOGY.

small intestine, and the part below almost wholly the large in-
testine. The limit between the two is soon indicated by a
projection, the caecum. The intestine separates from the abdominal
wall, the remains of the attachment appearing at the third month,
and sometimes later, as a thread-like appendage to the lower part
of the ileum. Convolutions then begin to form, and an enlarge-
ment in the region of the liver, which is the stomach.

In what way is the posterior opening in the intestine
formed ?

By the establishment of a communication between the cloaca, or
tube common to the gut and allantois, and a depression outside of
the body at about the sixth or seventh week. At the same time a
septum, which is the future perineum, separates the intestine from
the organs forming the allantois. The mouth is formed in the
same manner.

In what way are the salivary glands, the pancreas, and
the liver developed?
The liver commences as a projection formed by two primitive
hepatic ducts, which divide and subdivide. At the periphery of
the ducts are solid masses of cells which proceed from the hypo-
blast. The mass of the gland is developed from the mesoblast.
The liver secretes as early as the third month. The pancreas is
also formed from the mesoblast, as are also the salivary glands.
The lining of their ducts is, however, derived from the hypoblast.

The Foetal Circulation.

Describe the foetal circulation ?

The blood in the placenta, aerated and well nourished, passes
up the umbilical vein to the navel, where it enters the body of the
foetus, and, after a short course, reaches the liver, where it is split up
into two streams, one of which supplies the lobes of the liver, while
the other passes through the ductus venosus, which lies in the longi-
tudinal fissure of the liver, into the inferior vena cava and right
auricle of the heart, but instead of passing into the right ventricle
it is directed by the Eustachian valve along the back of the auricle

THE DEVELOPMENT OF ORGAN'S. L85

to the foramen ovale, and immediately enters the left auricle; the
left auricle, contracting, propels it into the left ventricle, which
drives it into the general circulation.

What is the difference in the circulation of blood in the
inferior vena cava from that of the superior vena
cava?

The blood returning from the head, or superior vena cava, |
into the right auricle and enters the right ventricle (which the
blood from the inferior vena cava does not). When the right
ventricle contracts the blood is driven into the pulmonary artery,
but instead of being distributed through the lungs it is directed
through a channel given off by the left pulmonary artery, known
as the ductus arteriosus, into the aorta just beyond the point where
the left subclavian is given off from that vessel. The right ventricle
and the left ventricle may, therefore, be said to drive the blood
through the general circulation in fcetal life. As the result of this,
however, it will be seen that in the aorta we have blood, half of
which is aerated and halfof which is not.

In what way does the blood return to the placenta to be
nourished and oxygenated ?

It passes through the descending aorta, the common iliacs, and
the umbilical artery, by which it reaches the placenta.

What changes take place in the circulation at birth ?

Respiration is commenced, the lungs become expanded, and. in
consequence of this, the pulmonary vessels permit the blood to
traverse them freely. The ductus arteriosus being no longer
required, contracts and shrivels up, but remains as a fibrous cord.
At the same time the detachment of the placenta leads to the im-
mediate arrest of the flow of blood from the umbilical arteries, and
no flow passes along the umbilical vein. The ductus renosus
contracts, the currents of the superior and inferior vena cava mix
in the right side of the heart, and the Eustachian valve and the
foramen ovale become useless.

INDEX.

ABDUCENT nerve, 143
Aberration, chromatic, 156

Absorption, 73

Accelerator ganglion of the heart, 37
nerve, 38

Accommodation of eye, 155

Acid-albumin, 20

Action of muscles, 104

Afferent nerves, 114

Agrammatism, 165

Albumen, 19

Albuminous foods, 102

Alimentary canal, development of,
176, 183

Alkali-albumin, 20

Allantois, 178

Amnesic aphasia, 165

Amnion, 177

Amylolopsin, 67

Anfemia, 30

Anelectrotonus, 115

Animal heat, 76

source of, 77

Anterior columns, 119

Aperistalsis, 65

AphEemia, 165

Aphasia, 164

Aphonia, 164

Apncea, 53

Appendages of the skin, 97

Aqueous humor, 154

Area opaca, 175
pellucida, 174

Argyll Robinson pupil, 158

Arteries, 40

Arterioles, 46

Arytenoid cartilages, 162

Asphyxia, influence of, on blood-
pressure, 44

Astigmatism, 156

Auditory canal, 159
nerve, 143

Auricles of the heart, 31
functions of, 32
Auriculo-ventricular valves, 33
Automatism, 124
Axis cylinder, 112

BILE, 71
acids, 71

pigments, 71
Bipolar cells, 119
Bizzozero, blood plaque of, 24
Bladder, 88
Blastoderm, 174
Blind spot, 153
Blood, the, 21

coagulation of, 28

pressure, 42
Bloodvessels, 39

of brain, 136

development of, 181
Body cavity, 176
Boundary zone of kidney, 81
Brain, weight of, 135
Bronchial veins, 49
Buffy coat, 30
Burdach's column, 120

CALCIUM phosphate in milk, 102
Calyx of kidney, 83
Capacity of the parts of the vascular

system, 42.
Capillaries, 39
Carbohydrates, 20
Carbonic dioxide, 51
Cardiac nerves, 38

veins, 34
Casein, 20

Cavities of the heart, 31
Centre for deglutition, 131
for respiration, 131

INDEX.

187

Centre for urination, 89

for vomiting, 131

inhibitory, 131

vasomotor, l".l
Centrifugal nerves, 1 13
Centripetal nerves, 113
Cerebellar tract, 124
Cerebellum, 135
Cerebral localization, 138
< lerebrum, 137
Cerumen, 159
Cervical sympathetic, 1 66
Chemical basis of the body, 17

changes in muscles, 109

composition of the liver, 72
Chiasm, optic, 141
Cholesterin, 71
Choluria, 94
Chorda dorsalis, 175

tympani nerve, 56
Chorda tendinea?, -".4
Chorion. 177
Choroid coat, 151
Chromatic aberration, 156
Chyluria, 94
Chyme, 63
Ciliary muscle, 151

processes, 151
Cilio-8pinal centre, 131
Circulation, 35

through heart, 35
Classification of proteids, 19
Coagulation of the blood, 28
of the arteries, 40

of the eye, 149
Color-blindness. I".ii
Color of the bile, 71

of the blood, 22

of the urine, 91
Colostrum, 101
Columns carnese, 35
Columns of the spinal cord, 118
Colloids 75
Complemental air, 50
Course of the medullary fibres, 11s!
Cones of the eye, 153
Consciousness, 137
i ionsistency of muscle, 105
Constituents of the bl 1, 23

of milk, 102
Contraction of muscles, 99
Convolutions of brain, 138
Cornea, 1 ."> 1
Coronary arteries, 34

Corpora quadrigemina, 133

striat
Corpus luteuru, 171
Corpuscles, nerve, L16, 147

red blood, 22
Cortex of kidney, 81
Corti, organ of, 1'il
Coughing, 5 I

Coverings of eye, l in

Cranial nerves. 1 1 1

• Iranium, development of, 17'.'

Cricoid cartilage, 162

Crossed pyramidal tracts, 120, 122,

1 2'.)
Crura cerebri, 133

>lline lens, 154
Crystalloids

DECIDUA menstruaJis, 170
refiexa, 1 7'.»

serotina, 179

vera, 179
Decussation, 12'.»
Defibrmated blood, 29
Definition of physiology, 17
Deglutition, .">'.>. 131
Depressor nerves,
Development, 173

of organs, 1 7'.i
Diabetes insipidus, 94

mellitus, 94
Diapedesis, 24

Diastatic action of saliva, ">.">, 58
Diffusion, 7 1
Digestion. ."> 1
Dioptric media, 158
Diplopia. 156
Direct cerebellar tract, 124, 130

pyramidal trad-. 120, 122. L29
Discus proligerus, 169
Ductus arteriosus, 1 8 1

venosus, 184
Dysperistalsis, 65
Dyspnoea, 53

[?AK. development of. 183
J F.tl'erent nerves, 160
L02
Elasticity of muscles, I'"''
Electrical phenomena of mm I

Electrotonus, l l 5
Endocardium, 32

188

INDEX.

Fmbryonal heart, 31

Emmetropia, 157

Endolymph, 160

Endosmosis, 73

Entopic images, 156

Epiblast, 174

Epididymis, 172

Epiglottis, 164

Euperistalsis, 65

Eupncea, 53

Eustachian tube, 160

Excretion, 97

Expiration, 49

External ear, 160

Extremities, development of, 179

Extrinsic cardiac nerves, 38

Eye, 149

development of, 182
Eyeball, 150,
Eyelashes, 149

FACIAL nerve, 143
Falling energy, 110
Fallopian tubes, 169
Far point, 155
Fats, 21, 102
Feces, amount of, 72
Fecundation, 173
Fibrin, 20, 28
Fibrin-ferments, 28
Fibrinogen, 19
Fibrinoplastin, 28
Filtration, 74
Flesh, 94

Foetal circulation, 184
Fourth ventricle, 129
Functions of the bladder, 88

of the blood, 21

of the coats of the arteries, 40

of the gray matter of cord, 122
if the heart, 32

of the kidneys, 81

of the liver, 71

of the skin, 95

of tracts of cord, 122

of the white matter of cord, 122

of the cardiac valves, 33

GANGLION of the heart, 35
Gases of the blood, 27
of the stomach, 63
Gastric digestion, 62

Gastric juice, 62

Gelatinous substance of Rolando, 120

Generation, 167

Generative organs of female, 168

of male, 171
Germinal area, 174

vesicle, 169
Globulins, 19
Glomerulus, 84
Glosso-pharyngeal nerve, 143
Glycogen, 70
Glycosuria, 94
Goll's column, 122
Graafian vesicles, 168
Gray matter of cord, 118

H^MATIN, 27
Haemoglobin, 27
Harmoglobinuria, 94
Hair, 97
Head folds, 176
Hearing, 158
Heart, the, 31

development of, 189

embryonal, 31

weight of, 31

sounds of, 36

suction of, 32

valves of, 33
Heat, animal, 76

dissipation, 78

production, 78
Heintz's test, 71
Hemianopsia, 157
Hiccough, 54
Hippuric acid, 93
Humors of the eye, 154
Hypermetropia, 157
Hypoblast, 1 74
Hypoglossal nerve, 144

Indifferent point, ne

1 Indol, 67
Inhibitory centre, 131

ganglion of the heart, 35
Injuries of optic nerve, 141
Inspiration, 49
Intestinal digestion, 66
Inversion of images, 154
Iris, 152
Irritability of muscle, 107

INDEX.

189

KATELECTROTONUS, [15
Kidneys, 81
Kinetic energy, 99
Kreatin and kreatinin, 106

LABYRINTH of kidney. B2
Lachrymal glands, 149
l.s, 74
Lactic acid, 62
Lactiferous ducts, 98
Laminae dorsalis, 175
Large intestine, function of, 72 .
Larynx, 162

muscles of, 1 62
Latent period, 1 lit

-I columns of spinal cord, 120
Laughing, 54

Laws of itracl ion, l L6

Laxator tympani muscle, 160

Left heart, 31

Lens, 154

Lesions of spinal cord, 127

Leucin, 67

Leucocythamia. "ill

Ligation of coronary arteries, 34

Liquor amnii, 17s

Liver, 68

Locus niger, 132

MACULA lutea, 153
Male sexual organs, 150
Malpighiaa body, 83
Maltose, 55
Mammary glands, 98
Masl ication, 59
Maximum stimulation, 110

contraction, 111
Medulla of kidney, 81

oblongata, 128
Medullary grooye, 175
Meibomian glands, 1 1'.l
Meissner's plexus, 64
Membrana decidua, I 79
Membranes of brain and cord, 1 1 8
Menstruation, 170
Mesoblast, 174
Metabolism, 98
M icrocytes, 24
Milk, 98

Milk-curdling ferments, 63, 67
Milk globules, 100

plasma, 100

Millon's reagent, 20

[anglion of the heart, 37

nerve-, I I I
Movements of respiration, 49

of I lie heart, .'!5

of the stomach, 60
Multipolar cells, 1 19
Muscle, ciliary, I 19

laxator tympani, I 'ill

plasma, 105

>r tympani, 160
Muscles, 104

of larynx, 163
Musculi papillares, 35
Myopia, 157
Myosin, 19, 105

NAILS, 97
Near point, 155
Negative variation, H>7, 114
Neural cavity, 17i>
Nerve, abducent, 143

auditory, 143

corpuscles, 116

facial, 14:;

glosso-pharyngeal, 143

hypoglossal, 1 11

oculo- motor, 141

olfactory, 141

pathetic, 142

pneumogastric, 1 1 1

spinal accessory, I 1 1

sublingual, 144

sympathetic, 165

vagus, 1 14
Nerves of the kidney, 87

of special sense, 145

of the stomach, 02

of taste, 147
Nervi nervorum, I 12
Nervous mechanism of deglutition
60
of the heart, 37

of heal. 7S

of respiration, 53

of speech, 163

of urinatioi
Nervous system, 112

development of, 181
Neuroglia, 118
Nose, developmenl of, •■
Nbtochord, 175
Number of heart valves, 33

190

INDEX.

Nourishment of heart, 34
Nystagmus, 158

OBJECT of respiration, 48
Oculo-motor nerve, 141
Odor of the blood, 22
Olfactory nerve, 141
Olivary body, 129
Optic chiasm, 141

lobes, 133

nerve, 141

thalami, 133
Organ of Corti, 161
Organs of generation, 168
Otoliths, 160
Ovaries, 168
Ovule, 169
Ovum, 170
Oxyhemoglobin, 22

PANCREATIC digestion, 66
ferments, 67
Papillae of the skin, 95
Paraglobulin, 19
Parapeptone, 63
Paraphasia, 165
Parotid, 55

Parts of the kidney, 86
Pathetic nerve, 142
Pepsin, 62
Peptones, 19
Pericardium, 36
Peristalsis, 64
Perspiration, 79

function of, 79
Pettenkofer's test, 71
Physical forces of the circulation, 45
Physiology of the spinal nerves, 117
Placenta, 179
Plasma, blood, 23

milk, 100

muscle, 105
Plethora, 30

Pneumogastric nerve, 38, 144
Pons Varolii, 133

Posterior columns of spinal cord, 119
Presbyopia, 157
Pressor fibres, 39
Primitive fibril, 112
Primitive groove, 175
Processes, ciliary, 151
Prostate gland, 173

Proto vertebrae, 175
Proteids, 18
Ptyalin, 58
Pulse, 47

rapidity of, 37
Pupil, 152

Pupillary movement, 152
Pyramids of kidney, 83

of medulla oblongata, 128

QUADRIGEMINAL bodies, 133
• Quantity of the bile, 72
Quantity of the blood, 28
of blood expelled, 35
of the saliva, 55

RAMI communicantes, 165
Ranvier's nodes, 112
Rate of the heart, 37

of respirations, 51
Reaction of muscles, 109

of the blood, 22

of the urine, 91
Recurrent sensibility, 117
Reflex action, 124

inhibiting centre, 126
Refraction, 155
Reserve air, 50
Residual air, 50
Respiration, 48
Respiratory centre, 53, 131
Restiform bodies, 117
Retina, 153
Right heart, 31
Rising energy, 110
Ritti-Valli law, 118
Rods of eye, 153

Rolando, gelatinous substance of, 120
Roots of trifacial nerve, 142
Rouleaux, 25

SALIVA, 54
Salivary centre, 120
digestion, 54
glands, 54
Salts, 94

of urine, 93
Sclerotic coat, 150
Sebaceous glands, 97
Secretion, 97

INDEX.

191

Section of vagi, 39
Segmentation of ovum, 17.''.
Semen, 172

Semicircular canals, 160
Semilunar valves, 33
Sense of sight, 149

of smell, 148

of taste, 147

of touch, 146
Sensibility, 146
Sensory nerves, 114
Serum, blood, 23
Setschenow's centre, 131
Sighing, 54
Bight, 149

Size of the kidneys, 81
Skatol, 67
Skin, 95

Smell, sense of, 148
Sneezing, 54
Sobbing, 54
Somatopleure, 176
Sounds of the heart, 36
Source of animal heat, 76
Special sense.-. I 45
Specific gravity of the blood, 23
of milk, 98
of urine, 90
Speech, 161

centre, 138
Speed of the circulation, 48
Spermatozoids, 1 72
Spherical aberration, 156
Spinal accessory nerve, 144

nerves, ID 7
Splanchnic, 167

Splanchnics, influence of, on peristal-
sis, 65
Splanchnopleure, 176
Stapedius muscle, 158
Starch, 20
Starches, 102
Starvation, 103
Steapsin, 68
Stimulation <>f vagus nerves, 38

of accelerator nerves, 39
Stomach, 60
Sublingual nerve, 144

saliva, 55
Submaxillary saliva, 55
Suction power of heart, 32
Sudoriferous gland-. 96
Sugar, 20
Summation, 111

96

Sympathetic, 56
nerve, 165

TACTILE sensibilitv, 146
Tail folds, 176
Taste, 147

buds, 147

goblet- 1 17

nerves of, I 18

of the blood, 23
Temperature of the blood, 23
Tensor tympani muscle, 160
Testicles, 171
Tests for proteids, 20
Tetanus, 1 1 1
Thyroid cartilage, 162
Tidal air, 50

Tractus intermedio-lateralis, 119
Transference, 1L'4
Trifacial nerve, 142
Trammer's test, 21
Trypsin, 67

Fallopian, 168
Tubuli seminiferi, 172

uriniferi, 83
Tiirck's columns, 122
Tympanic membrane, 159
Tyrosin, 67

UMBILICAL veins, 185
vesicle, 176
Unipolar cell, 119
Urea, 92
Ureters, 87
Uric acid, 93

Urinse potus, cibi, and sanguinis, yi
Urine, 90
Uterus, 168

VAGINA, 168
Vagus nerve, 18, lit
Valves of the heart, .'j:;

of the vein-. 1 1
Variations in the blood, 23
Vasa recta, 86
Vas deferens, 172
Vasomotor centre, 43, 131

nerves, 43
Vegetable foods, 102
Veins, 37

card:

192

INDEX,

Ventricles of the heart, 31

weight of, 31
Vernix caseosa, 97
Vertebrae, development of. 1 79
Vesiculre seminales, 172
Vesicular columns of Clark, 119
Visceral plates, 176
Visual purple, 154
Vital capacity, 50
Villi of chorion, 178
Villus, 74
Vitellin, 19

Vitelline membrane, 177
Vitreous humor, 154
Voice, 161
Vomiting, 64

centre, 131

WATER, 91, 94
Weight of brain, 135
of heart, 31
of left ventricle, 31
"White blood- corpuscles, 24

matter of the spinal cord, 118
Work of respiratory muscle, 51

V ANTHO-PROTEIC reaction, 20
70NApellucida, 169

STANDARD

Medical and Surgical Works

PUBLISHED BV

W. B. SAUNDERS. 925 Walnut Street, Philadelphia, Pa.

PAGE

•American Text- Hook of Applied Thera-
peutics 4

'American Text- Hook of Dis. of Children . 9
*An American Text-Hook of Diseases of the

Eye, Ear, Nose, and L'hroat 31

•An American Text-Hook of Genito-Uri-

nary and Skin Diseases 31

*American Text- Hook of Gynecology ... 8
•American Text-Book of Obstetrics ... 5
•American Text-Book of Physiology ... 3
•American Text-Book of Practice .... 6
*American Text- Hook of Surgery ... 7
Anders' Theory and Practice of -Medicine . 31

Ashton's Obstetrics 28

Atlas of Skin Diseases 12

Ball's Bacteriology 28

Bastin's Laboratory Exercises in Botany . 22

Heck's Surgical Asepsis 26

Boisliniere's Obstetric Accidents, Emer-
gencies, and Operations 23

Brockway's Physics 28

Burr's Nervous Diseases 26

Butler's Materia Medica and Therapeutics 29
Cerna's Notes on the Newer Remedies . . 18
Chapman's Medical Jurisprudence . . . . 26
Church and Peterson's Nervous and Men-
tal Diseases 3t

Clarkson's Histology 14

Cohen and Eshner's Diagnosis 28

Corwin's Diagnosis of the Thorax . . . . 29

Cragin's Gynaecology 28

-hank's Text-Hook of Bacteriology . 13

DaCosta's Manual of Surgery 26

De Schweinitz's Diseases of the Eye ... 15

Dorland's Obstetrics 26

Frothingham's Bacteriological Guide ... 16

Garrigues' Diseases of Women 20

Gleason's Diseases of the Ear 28

*Gould and Pyle's Anomalies and Curi-
osities of Medicine 30

Griffin's Materia Medica and Therapeutics 26

Griffith's Care of the Baby 24

( in^'s Autobiography 10

Hampton's Nursing 23

Hare's Physiol. igy .'8

Hart's Diet in Sickness and in Health . . 22

Haynes' Manual of Anatomy 26

Heisler's Embryology 31

Hirst's Obstetrics 31

Hyde's Syphilis and Venereal Diseases . . 26
Jackson and Gleason's Diseases of the Eye,

Nose, and Throat 28

Jewett's Outlines of Obstetrics 21

Keating's Pronouncing Dictionary .... 10

Keating' s Life Insurance 23

Keen's Operation Blanks 22

Kyle's Diseases of Nose and Throat . . .26
Laine's Temperature Charts 18

1 AGS

Lockwood's Practice of Medicine .... 26
Long's Syllabus ol I . ■ . . 20

Macdonald's Surgical 1 liagnosis and 1 reat-

ment 31

McFarland's Pathog l . . . . . 16
Mallory and Wright's Pathological Tech-
nique 31

Martin's Surgery 28

Martin's Minor Surgery, Bandaging, and

Venereal Diseases 28

Meigs' Feeding in Early Infancy 16

Moore's Orthopedic Surgery 31

Morris' Materia Medica and 'Therapeutics 28

Morris' Practice of Medicine 28

Morten's Nurses' Dictionary 24

Nancrede's Anatomy and Dissection ... 17

Nancrede's Anatomy 28

Norris' Syllabus of Obstetrical Lectures . 21

Penrose's Gynecology 31

Powell's Diseases of Children 28

Pye's Elementary Bandaging and Surgical

Dressing 29

Raymond's Physiology 26

Rowland's Clinical Skiagraphy 14

Saundby's Renal and Urinary Diseases . . 29
•Saunders' American Year-Book of Medi-
cine and Surgery 32

Saunders' Pocket Medical Formulary . . 19
Saunders' Pocket Medical Lexicon .... 32
Saunders' New Aid Series of Manuals . 25, 26
Saunders' Series of Question Compends 27, 28

Sayre's Practice of Pharmacy 28

Semple's Pathology and Morbid Anatomy 28
Semple's Legal Medicine. 'Toxicology, and

Hygiene 28

Senn's Genito-Urinary 'Tuberculosis . . .31

Senn's Tumors 11

Senn's Syllabus of Lectures on Surgery . . 21
Shaw's Nervous Diseases and Insanity . . 28

Starr's Diet- Lists for Children 24

Stelwagon's Diseases of the Skin 28

Stengel's Manual of Pathology 26

Stevens' Materia Medica and Therapeutics 18

Stevens' Practice of Medicine 17

Stewart's Manual of Physiology 21

Stewart and Lawrance's Medical Elec-
tricity 28

Stoney's Practical Points in Nursing . . . 1 3
Sutton and Giles' Diseases ol Women . .26
Thomas's Diet-List and Sick-Room I >ietary24
Thornton's Dose- Book and Manual of Pre-
scription-Writing 26

Van Valzah and Nisbet's Diseases of the

Stomach

Vierordi and Stuart's Medical Diagni sis . ta

Warren's Surgical Path.. logy 11

Wolffs Chemistry 28

Wolffs Examination of Urine 28

The works indicated thus (*) are sold by subsi usually

tin.. ugh travelling solicitors, but they can be obtain in the office

(charges of shipment prepaid) by remitting the quoted prices. Full dlSCriptivt
SU< h works will be sent to any address upon appli. at ion.

All the other BOOKS advertised in this catalogue are commonly for sale by 6 <okitU*rt in
all parts of the United States ; but any book will be sent by the publisher to any address
(post-paid) on receipt of the price herein given.

<

a
a

GENERAL INFORMATION.

One Price. One price absolutely without deviation. No discounts

allowed, regardless of the number of books purchased at one
time. Prices on all works have been fixed extremely low, with
the view to selling them strictly net and for cash.

Orders. An order accompanied by remittance will receive prompt

attention, books being sent to any address in the United States,
by mail or express, all charges prepaid. We prefer to send
books by express when possible, and if sent C. O. D. we pay
all charges for returning the money. Small orders of three
dollars or less must invariably be accompanied by remit-
tance.

How to Send There are four ways by which money can be sent at our
Money by risk, namely: a post-office money order, an express money
Mail. order, a bank-check (draft), and in a registered letter. Money

sent in any other way is at the sender's risk. Silver should not

be sent through the mail.

Shipments. All books, being packed in patent metal-edged boxes, neces-

sarily reach our patrons by mail or express in excellent condi-
tion.

Subscription
Books.

Latest
Editions.

Bindings.

Descriptive
Circulars.

Books in our catalogue marked " For sale by subscription
only " may be secured by ordering them through any of our
authorized travelling salesmen, or direct from the Philadelphia
office ; they are not for sale by booksellers. All other books
in our catalogue can be procured of any bookseller at the
advertised prices, or directly from us. We handle only our own
publications, and cannot supply second-hand books nor the
publications of other houses.

In every instance the latest revised edition is sent.

In ordering, be careful to state the style of binding desired —
Cloth, Sheep, or Half-Morocco.

A complete descriptive circular, giving table of contents, etc.
of any book sold by subscription only, will be sent free on
application.

CATALOGUE OF MEDICAL WORKS.

For Sale by Subscription.

AN AMERICAN TEXT-BOOK OF PHYSIOLOGY. Edited by
William II. Howell, Ph.D., M.I)., Professor of PI , the

Johns Hopkins University, Baltimore, Md. < me handsome octavo volume
of 1052 pages, fully illustrated. Prices: Cloth, $6.00 net; Sheep or Half-
Morocco, $7.00 net.

This work is the most notable attempt yet made in America to combine in
one volume the entire subject of Human Physiology by well-known teachers
who have given especial study to that part of the subject upon which they write.
The completed work represents the present status of the science of Physi
particularly from the standpoint of the student of medicine and of the medical
practitioner.

The collaboration of several teachers in the preparation of an elementary text-
book of physiology is unusual, the almost invariable rule heretofore having been
for a single author to write the entire book. One of the advantages to be derived
from this collaboration method is that the more limited literature necessary for
consultation by each author has enabled him to base his elementary account
upon a comprehensive knowledge of the subject assigned to him; another, and
perhaps the most important, advantage is that the student gains the point of view
of a number of teachers. In a measure he reaps the same benefit as would be
obtained by following courses of instruction under different teachers. The
different standpoints assumed, and the differences in emphasis laid upon the
various lino of procedure, chemical, physical, and anatomical, should give the
student a better insight into the methods of the science as it exists to-day. The
work will also be found useful to many medical practitioners who may wish to
keep in touch with the development of modern physiology.

The main divisions of the subject-matter are as follows: General Physiology
of Muscle and Nerve — Secretion — Chemistry of Digestion and Nutrition —
Movements of the Alimentary Canal, Bladder, and Ureter— Hlood and Lymph
— Circulation — Respiration— Animal Heat — Central Nervous System —Special
Senses — Special Muscular Mechanisms — Reproduction — Chemistry of the
Animal Body.

CONTRIBUTORS:
HENRY P. BOWDITCH, M. D., WARREN P. LOMBARD, M. D.,

Professor of Physiology, Harvard Medi- Physiology, University of

cal School. Michigan.

JOHN G. CURTIS, M. D., ORAHAM TUSK Ph D

Professor of Physiology, Columbia Uni- ^ahabi lusii, rn. 1;.,

versity, X. X. (College of Physicians 'or ,of P'»y*ology, Yale Medtcal

and Surge- Scnool.

HENRY H. DONALDSON, Ph.D., W. T. PORTER, M. D.,

Head-Professor of Neurology, Univer- Assistant Professor of Physiology, H.<r-

sity of Chicago. I Medical School.

W. H. HOWELL, Ph D., M D. EDWARD T. REICHERT. M. D.,

Professor of Physiology, Johns Hopkins or of Physi* rsity of

1 mversity. Pennsylvania.

FREDERIC S. LEE, Ph. D.,

Adjunct Professor of Ph HENRY SEWALL, Ph. D., M. D..

bia University. N. Y. (College of Depart

Physicians and Surgeons). incut, University of Denver.

IV. B. SAUNDERS'

For Sale by Subscription.

AN AMERICAN TEXT-BOOK OF APPLIED THERAPEU-
TICS. For the Use of Practitioners and Students. Edited by
James C. Wilson, M. D., Professor of the Practice of Medicine and of
Clinical Medicine in the Jefferson Medical College. One handsome octavo
volume of 1326 pages. Illustrated. Prices; Cloth, $7.00 net; Sheep or
Half- Morocco, $8.00 net.

The arrangement of this volume has been based, so far as possible, upon
modern pathologic doctrines, beginning with the intoxications, and following
with infections, diseases due to internal parasites, diseases of undetermined
origin, and finally the disorders of the several bodily systems — digestive, re-
spiratory, circulatory, renal, nervous, and cutaneous. It was thought proper to
include also a consideration of the disorders of pregnancy.

The list of contributors comprises the names of many who have acquired dis-
tinction as practitioners and teachers of practice, of clinical medicine, and of
the specialties.

CONTRIBUTORS :

Dr. I. E. Atkinson, Baltimore, Md.
Sanger Brown, Chicago, 1(1.
John B. Chapin, Philadelphia, Pa.
William C. Dabney, Charlottesville, Va.
John Chalmers DaCosta, Philada., Pa.
I. N. Danforth, Chicago, 111.
John L. Dawson. Jr., Charleston, S. C.
F. X. Dercum, Philadelphia. Pa.
George Dock, Ann Arbor, Mich.
Robert T. Edes, Jamaica Plain, Mass.
Augustus A. Eshner, Philadelphia, Pa.
J. T. Eskridge, Denver, Col.
F. Forchheimer, Cincinna'i, O.
Carl Frese, Philadelphia, Pa.
Edwin E. Graham, Philadelphia, Pa.
John Guiteras, Philadelphia. Pa.
Frederick P. Henry, Philadelphia, Pa.
Guy Hinsdale, Philadelphia, Pa.
Orville Horwitz, Philadelphia, Pa.
W. W. Johnston, Washington, D. C.
Ernest Laplace, Philadelphia, Pa.
A. Laveran, Paris, France.

Dr. James Hendrie Lloyd, Philadelphia, Pa.
John Noland Mackenzie, Baltimore, Md.
J. W. McLaughlin, Austin, Texas.
A. Lawrence Mason, Boston, Mass.
Charles K. Mills, Philadelphia, Pa.
John K. Mitchell, Philadelphia, Pa.
W. P. Northrup, New York City.
William Osier, Baltimore, Md.
Frederick A. Packard, Philadelphia, Pa.
Theophilus Parvin, Philadelphia, Pa.
Beaven Rake, London, England.
E. O. Shakespeare, Philadelphia. Pa.
Wharton Sinkler, Philadelphia. Pa.
Louis Starr, Philadelphia, Pa.
Henry W. Stelwagon, Philadelphia, Pa.
James Stewart, Montreal. Canada.
Charles G. Stockton, Buffalo, N. Y.
James Tyson, Philadelphia, Pa.
Victor C. Vaughan, Ann Arbor, Mich.
James T. Whittaker, Cincinnati, O.
J. C. Wilson, Philadelphia, Pa.

The articles, with two exceptions, are the contributions of American writers.
Written from the standpoint of the practitioner, the aim of the work is to facili-
tate the application of knowledge to the prevention, the cure, and the allevia-
tion of disease. The endeavor throughout has been to conform to the title of
the book — Applied Therapeutics — to indicate the course of treatment to be
pursued at the bedside, rather than to name a list of drugs that have been used
at one time or another.

While the scientific superiority and the practical desirability of the metric
system of weights and measures is admitted, it has not been deemed best to
discard entirely the older system of figures, so that both sets have been given
where occasion demanded.

CATALOGUE OF ME PICA I. WO A' AS.

For Sale by Subscription.

AN AMERICAN TEXT-BOOK OF OBSTETRICS. Edited by
Richard C. Norris, M. I>. ; Art Editor, RoBERl L. DICKINSON, M. I>

One handsome octavo volume of over iooo pages, with nearly 900 colored
and half-tone illustrations. Prices: i o; Sheep or Half- Morocco,

$8.00.

The advent of each successive volume of the series of the American Text-
Books has been signalized by the most flattering comment from both the Press
and the Profession. The high consideration received by these text-books, and
their attainment to an authoritative position in current medical literature, have
been matters of deep international interest, which finds its fullest expression in
the demand for these publications from all parts of the civilized world.

In the preparation of the "AMERICAN TEXT-BOOK OF OBSTETRICS" the
editor has called to his aid proficient collaborators whose professional prominence
entitles them to recognition, and whose disquisitions exemplify Practical
Obstetrics. While these writers were each assigned special themes for dis-
cussion, the correlation of the subject-matter is, nevertheless, such as ensures
logical connection in treatment, the deductions of which thoroughly represent
the latest advances in the science, and which elucidate the best modern methods
of procedure.

The more conspicuous feature of the treatise is its wealth of illustrative
matter. The production of the illustrations had been in progress for several
years, under the personal supervision of Robert L. Dickinson, M. l)..t" v
artistic judgment and professional experience is due the most sumptuously
illustrated work of the period. By means of the photographic art, combined
with the skill of the artist and draughtsman, conventional illustration is super-
seded by rational methods of delineation.

Furthermore, the volume is a revelation as to the possibilities that may be
reached in mechanical execution, through the unsparing hand of its publisher.

4 OVIKIKI TOIt»:

Dr. James C. Cameron.
Edward P. I >.i vis.
Robert L. Dickinson.
Charles Warrington Earle.
James H. Etheridge.
Henry J. Garrieues.
Barton Cooke Hirst.
Charles Jewett,

. Howard A. Kelly.
Richard C. N
Chauncey D. Palmer.
Theophilus Parvin.
George A. Piersol.
I rd Reynolds.

Henry Schwarz.

" At first glance we are overwhelmed by the magnitude of this work in several respects,
viz. : First, by the size of the volume, then by the array of eminent teachers in this depart-
ment who have taken part in it> production, then by the profuseness and character of the
illustrations, and last, but not least, the conciseness and 1 learness with which the text is ren-
dered. This is .m entirely new positi m, 1 mbodj ing the highest knowledge of the art as

it stands to-day by authors who occupy the front rank in their specialty, and dure are many
of them. We cannot (urn over these pages without being struck by the superb illustrations
which adorn so many of them. We nfident that this most practical work will find

instant appreciation by practitioners as well as students." — Neiv York Medical Times.

Permit me to say that your American Ti xt-B i 'k of Obstetrics is the most magnificent
medical work that 1 have ever seen. I congratulate you and thank you for this superb work.
which alone is sufficient to place you first in the ranks of medical publishers.

With profound respect I am sincerely yours, Ai EX. J. C. Skene.

W. B. SAUNDERS'

For Sale by Subscription.

AN AMERICAN TEXT-BOOK ON THE THEORY AND
PRACTICE OF MEDICINE. By American Teachers. Edited
by William Pepper, M. D., LL.D., Provost and Professor of the Theory
and Practice of Medicine and of Clinical Medicine in the University of
Pennsylvania. Complete in two handsome royal-octavo volumes of about
iooo pages each, with illustrations to elucidate the text wherever necessary.
Price per Volume : Cloth, $5.00 net ; Sheep or Half-Morocco, #6.00 net.

VOLUME I. CONTAINS;

Hygiene. — Fevers ( Ephemeral, Simple Con-
tinued, Typhus, Typhoid, Epidemic Cerebro-
spinal Meningitis, and Relapsing) — -Scarla-
tina, Measles, Roth-eln, Variola, Varioloid,
V jccinia, Varicella, Mumps, Whooping-cough,
Anthrax, Hydrophobia, Trichinosis, Actino-

mycosis, Glanders, and Tetanus. — Tubercu-
losis, Scrofula, Syphilis, Diphtheria, Erysipe-
las, Malaria, Cholera, and Yellow Fever. —
Nervous, Muscular, and Mental Diseases etc.

VOLUME II. CONTAINS:

Urine (Chemistry and Microscopy). — Kid-
ney and Lungs. — Air-passages (Larynx and
Bronchi) and Pleura. — Pharynx, CEsophagus,
Stomach and Intestines (including Intestinal
Parasites), Heart, Aorta, Arteries and Veins.

— Peritoneum, Liver, and Pancreas. — Diathet-
ic Diseases (Rheumatism, Rheumatoid Ar-
thritis, Gout, Lithaemia, and Diabetes.) —
Blood and Spleen. — Inflammation, Embolism,
Thrombosis, Fever, and Bacteriology.

The articles are not written as though addressed to students in lectures, but
are exhaustive descriptions of diseases, with the newest facts as regards Causa-
tion, Symptomatology, Diagnosis, Prognosis, and Treatment, including a large
number of approved formulae. The recent advances made in the study
of the bacterial origin of various diseases are fully described, as well as the
bearing of the knowledge so gained upon prevention and cure. The subjects
of Bacteriology as a whole and of Immunity are fully considered in a separate
section.

Methods of diagnosis are given the most minute and careful attention, thus
enabling the reader to learn the very latest methods of investigation without
consulting works specially devoted to the subject.

CONTRIBUTORS :

Dr. J. S. Billings, Philadelphia.
Francis Delafield, New York.
Reginald H. Fitz, Boston.
James W. Holland, Philadelphia.
Henry M. Lyman, Chicago.
William Osier, Baltimore.

Dr. William Pepper, Philadelphia.
W. Gilman Thompson, New York.
W. H. Welch. Baltimore.
James T. Whittaker, Cincinnati.
James C. Wilson, Philadelphia.
Horatio C. Wood, Philadelphia.

" We reviewed the first volume of this work, and said : ' It is undoubtedly one of the best
text-books on the practice of medicine which we possess.' A consideration of the second
and last volume leads us to modify that verdict and to say that the completed work ts, in our
opinion, the best of its kind it has ever been our fortune to see. It is complete, thorough,
accurate, and clear. It is well written, well arranged, well printed, well illustrated, and well
bound. It is a model of what the modern text-book should be." — New York Medical Journal.

"A library upon modern medical art. The work must promote the wider diffusion of
sound knowledge." — American Lancet.

" A trusty counsellor for the practitioner or senior student, on which he may implicitly
rely." — Edinburgh Medical Journal.

CATALOGUE OF MEDICAL WORKS.

For Sale by Subscription.

AN AMERICAN TEXT-BOOK OF SURGERY. Edited by Wil-
liam W. Keen, M.D., LL.D., and J. William White, M. D., Ph. D.

Forming one handsome royal-octavo volume of 1250 pages (10x7 inches),
with 500 wood-cuts in text, and 37 colored and half-tone plates, many of
them engraved from original photographs and drawings furnished by the
authors. Prices: Cloth, $7. 00 net; Sheep or Half- Morocco, 38.00 net.

SECOND EDITION, REVISED AND ENLARGED,
With a Section devoted to "The Use of the Rbntgen Rays in Surgery."

The want of a text-book which could be used by the practitioner and at the
same time be recommended to the medical student has been deeply felt, espe-
cially by teachers of surgery; hence, when it was suggested to a nuni!
these that it would be well to unite in preparing a text-book of this description,
great unanimity of opinion was found to exist, and the gentlemen below named
gladly consented to join in its production. While there is no distinctive Amer-
ican Surgery, yet America has contributed very largely to the progress of modern
surgery, and among the foremost of those who have aided in developing this art
and science will be found the authors of the present volume. All of tbem are
teachers of surgery in leading medical schools and hospitals in the United States
and Canada.

Especial prominence has been given to Surgical Bacteriology, a feature which
is believed to be unique in a surgical text-book in the English language. Asep-
sis and Antisepsis have received particular attention. The text is brought well
up to date in such important branches as cerebral, spinal, intestinal, and pelvic
surgery, the most important and newest operations in these departments being
described and illustrated.

The text of the entire book has been submitted to all the authors for their
mutual criticism and revision — an idea in book-making that is entirely new and
original. The book as a whole, therefore, expresses on all the important sur-
gical topics of the day the consensus of opinion of the eminent surgeons who
have joined in its preparation.

One of the most attractive features of the book is its illustrations. Very
many of them are original and faithful reproductions of photographs taken
directly from patients or from specimens.

CONTRIBUTORS:

Dr. Charles H Burnett, Philadelphia.
Phineas S. Conner, Cincinnati.
Frederic S. Dennis, New York.
William VV. Keen, Philadelphia
Charles B Nancrede, Ann Arbor, Mich.
Roswell Park, Buffalo, N. Y.
Lewis S. Pilcher, New York.

Dr. Nicholas Senn, Chicago.

Francis J. Shepherd. Montreal, Canada.
Lewis A. Stimson, New York.
William Thomson, Philadelphia.
' J. Collins Warren, Boston,
j. William White, Philadelphia.

" If this text-book is a fair reflex of ihc present position of American surgery, we must
admit it is of a very high order of merit, and that English surgeons will have to look very
carefully to their laurels if they are to preserve a position in the van of surgical practice." —
London Lancet.

W. B. SAUNDERS'

For Sale by Subscription.

AN AMERICAN TEXT-BOOK OF GYNECOLOGY, MEDICAL
AND SURGICAL, for the use of Students and Practitioners.
Edited by J. M. Baldy, M. D. Forming a handsome royal-octavo volume,
with 360 illustrations in text and 37 colored and half-tone plates. Prices:
Cloth, #6.00 net; Sheep or Half-Morocco, #7.00 net.

In this volume all anatomical descriptions, excepting those essential to a clear
understanding of the text, have been omitted, the illustrations being largely de-
pended upon to elucidate the anatomy of the parts. This work, which is
thoroughly practical in its teachings, is intended, as its title implies, to be a
working text-book for physicians and students. A clear line of treatment has
been laid down in every case, and although no attempt has been made to dis-
cuss mooted points, still the most important of these have been noted and ex-
plained. The operations recommended are fully illustrated, so that the reader,
having a picture of the procedure described in the text under his eye, cannot fail
to grasp the idea. All extraneous matter and discussions have been carefully
excluded, the attempt being made to allow no unnecessary details to cumber
the text. The subject-matter is brought up to date at every point, and the
work is as nearly as possible the combined opinions of the ten specialists who
figure as the authors.

The work is well illustrated throughout with wood-cuts, half-tone and
colored plates, mostly selected from the authors' private collections.

CONTRIBUTORS :

Dr. Henry T. Byford.
John M. Baldy.
Edwin Cragin.
». H. Etheridge.
William Goodell.

Dr. Howard A. Kelly.
Florian Krug.
E. E. Montgomery.
William R. Pryor.
George M. Tuttle.

"The most notable contribution to gynecological literature since 1887 and the most

complete exponent of gynecology which we have. No subject seems to have been neglected,
.... and the gynecologist and surgeon, and the general practitioner who has any desire
to practise diseases of women, will find it of practical value. In the matter of illustrations
and plates the book surpasses anything we have seen." — Boston Medical and Surgical
"Journal.

"A valuable addition to the literature of Gynecology. The writers are progressive,
aggressive, and earnest in their convictions." — Medical News, Philadelphia.

" A thoroughly modern text-book, and gives reliable and well-tempered advice and in-
struction."— Edinburgh Medical Journal.

" The harmony of its conclusions and the homogeneity of its style give it an individuality
which suggests a single rather than a multiple authorship." — Annals of Surgery.

" It must command attention and respect as a worthy representation of our advanced
clinical teaching." — American Journal oj Medical Sciences.

CATALOGUE OF MEDICAL WORKS.

For Sale by Subscription.

AN AMERICAN TEXT-BOOK OF THE DISEASES OF CHIL-
DREN. By American Teachers. Edited by Louis Stark, M. 1).,
assisted by THOMPSON S. Westcott, M. D. In one handsome royal-8va
volume of 1190 pages, profusely illustrated with wood cuts, half-tone and
colored plates. Net Prices: Cloth, $7.00; Sheep or Half-Morocco, %

The plan of this work embraces a series of original articles written by some
sixty well-known psediatrists, representing collectively the teachings of tin
prominent medical schools and colleges of America. The work is intended to
be a practical book, suitable for constant and handy reference by the practi-
tioner and the advanced student.

One decided innovation is the large number of authors, nearly every article
being contributed by a specialist in the linj on which he writes. This, while
entailing considerable labor upon the editors, has resulted in the publication of
a work THOROUGHLY NEW AND ABREAST OF THIi TIMES.

Especial attention has been given to the latest accepted teachings upon the
etiology, symptoms, pathology, diagnosis, and treatment of the disorders of chil-
dren, with the introduction of many special formulae and therapeutic procedures.

Special chapters embrace at unusual length the Diseases of the Eye, Ear,
Nose and Throat, and the Skin ; while the introductory chapters cover fully the
important subjects of Diet, Hygiene, Exercise, Bathing, and the Chemistry of
Food. Tracheotomy, Intubation, Circumcision, and such minor surgical pro-
cedures coming within the province of the medical practitioner are carefully
considered.

CONTRIBUTORS :

Dr. Thomas S. Latimer, Baltimore.

Dr. S. S. Adams, Washington.

John Ashhurst, Jr., Philadelphia.
A. U. Blackader, Montreal, Canada.
Dillon Brown, New York.
Edward M. Buckingham, Boston.
Charles W. Burr, Philadelphia.
W. E. Casselberry, Chicago.
Henry Dwight Chapin, New York.
W. S. Christopher, Chicago.
Archibald Church, Chicago
Floyd M. Crandall, New York.
Andrew F. Currier, New York.
Roland G. Curtin, Philadelphia
J. M. DaCosta, Philadelphia.
I. N. Danforth, Chicago.
Edward P. Davis, Philadelphia.
John B. Deaver, Philadelphia.
G. E. de Schweinitz, Philadelphia.
John Doming, New York.
Charles Warrington Farle, Chi
W'm. A. Edwards, San Diego, Cal.
F. Forchheimer, Cincinnati.

J. Henry Fruitnight, New York.
Landon Carter Gray, New York.
J. P. Crozer Griffith, Philadelphia.
\\ . A. Hardaway. St. Louis.
M. P Hatfield, Chicago.
Barton Cooke Hirst, Philadelphia.
H. Illoway, Cincinnati.
Henry Jackson, Boston.
Charles G. Jennings, Detroit.
Henry Koplik. New York.

Albert R. Leeds, Hoboken, N. J.
J. Hendrie Lloyd, Philadelphia.
George Roe Lockwood, New York.
Henry M. Lyman, Chicago.
Francis T. Miles, Baltimore.
Charles K Mills, Philadelphia.
John H. Musser, Philadelphia.
'Thomas R. Neilson, Philadelphia.
W. P. Northrop, New York.
William Osier, Baltimore.
Frederick A Packard, Philadelphia.
William Pepper, Philadelphia.
Frederick Peterson, New York.
W. 1 . Plant, Syracuse, New York.
William M. Powell, Atlantic City.
B. Alexander Randall, Philadelphia.
Edward O. Shakespeare, Philadelphia

F. C. Shattuck, Boston,

J. Lewis Smith, New York.

LouU Starr, Philadelphia.

M. Allen Starr, New York.

J. Madison Taylor, Philadelphia.

Charles YV . Townsi nd, Boston,

James Tyson, Philadelphia.

W. S. Thayer, Baltimore.

Victor C. Vaughan, Ann Arbor. Mich

Thompson S. Westcott, Philadelphia.

Henry R. Wharton, Philadelphia.

J. Willi. on White. Philadelphia.

J-

C. Wilson, Philadelphia.

10 iv. B. SAUNDERS'

A NEW PRONOUNCING DICTIONARY OF MEDICINE, with
Phonetic Pronunciation, Accentuation, Etymology, etc. By John
M. Keating, M. D., LL.D., Fellow of the College of Physicians of Phila-
delphia; Vice-President of the American Pediatric Society; Ex-President
of the Association of Life Insurance Medical Directors; Editor " Cyclo-
paedia of the Diseases of Children," etc.; and Henry Hamilton, author
of " A New Translation of Virgil's ^Eneid into English Rhyme ;" co-
author of " Saunders' Medical Lexicon," etc. ; with the Collaboration of
J. Chalmers DaCosta, M. D., and Frederick A. Packard, M. D.
With an Appendix containing important Tables of Bacilli, Micrococci,
Leucoma'ines, Ptomaines, Drugs and Materials used in Antiseptic Sur-
gery, Poisons and their Antidotes, Weights and Measures, Thermometric
Scales, New Official and Unofficial Drugs, etc. One very attractive volume
of over 800 pages. Second Revised Edition. Prices: Cloth, $5.00 net-;
Sheep or Half- Morocco, $6.00 net; with Denison's Patent Ready- Refer-
ence Index ; without patent index, Cloth, $4.00 net ; Sheep or Half-
Morocco, $5.00 net.

PROFESSIONAL, OPINIONS.

" I am much pleased with Keating's Dictionary, and shall take pleasure in recommending
it to my classes."

Henkv M. Lyman, M. D.,
Professor of Principles and Practice of Medicine, Rush Medical College, Chicago, III.

" I am convinced that it will be a very valuable adjunct to my study-table, convenient in
size and sufficiently full for ordinary use."

C. A. Linusley, M. D.,
Professor of Theory and Practice of Medicine, Medical Dept. Yale University ;

Secretary Connecticut State Board of Health, New Haven, Conn,

AUTOBIOGRAPHY OF SAMUEL D. GROSS, M. D., Emeritus Pro-
fessor of Surgery in the Jefferson Medical College of Philadelphia, with
Reminiscences of His Times and Contemporaries. Edited by his sons,
Samuel W. Gross, M. D., LL.D., late Professor of Principles of Surgery
and of Clinical Surgery in the Jefferson Medical College, and A. Hali.er
Gross, A. M., of the Philadelphia Bar. Preceded by a Memoir of Dr.
Gross, by the late Austin Flint, M. D., LL.D. In two handsome volumes,
each containing over 400 pages, demy 8vo, extra cloth, gilt tops, with fine
Frontispiece engraved on steel. Price per Volume, $2.50 net.
This autobiography, which was continued by the late eminent surgeon until
within three months of his death, contains a full and accurate history of his
early struggles, trials, and subsequent successes, told in a singularly interesting
and charming manner, and embraces short and graphic pen-portraits of many
of the most distinguished men — surgeons, physicians, divines, lawyers, states-
men, scientists, etc. — with whom he was brought in contact in America and in
Europe ; the whole forming a retrospect of more than three-quarters of a century.

CATALOGUE OF MEDICAL WORKS. II

SURGICAL PATHOLOGY AND THERAPEUTICS. By John
Collins Warren, M. D., LL.D., Professor of Surgery, Medical Depart-
ment Harvard University; Surgeon to the Massachusetts General Hospital,

etc. A handsome octavo volume of 832 pa^es, with 136 relief and litho-
graphic illustrations, ^ of which are printed in colors, and all of which
were drawn by William J. Kaula from original specimens. Prices: Cloth,
$6.00 net; Half-Morocco, $7.00 net.

" The volume is for the bedside, the amphitheatre, and the ward. It deals
with things not as we see them through the microscope alone, but as the prac-
titioner sees their effect in his patients ; not only as they appear in and affect
culture-media, hut also as they influence the human body; and, following up
the demonstrations of the nature of diseases, the author points out their logical
treatment." [New York Medical Journal). " It is the handsomest spe<
of hook-making * * * that has ever been issued from the American medical
press " {American Journal of the Medical Sciences, Philadelphia).

Without Exception, the Illustrations are the Best ever Seen in a
Work of this Kind.

"A most striking and very excellent feature of this book is its illustrations. Without ex-
ception, from the point of accuracy and artistic merit, they are the best ever seen in a work
of this kind. * * * Many of those representing microscopic pictures are so perfect in their
coloring and detail as almost to give the beholder the impression that lie is looking down the
barrel of a microscope at a well-mounted section. " — Annals of Surgery, Philadelphia.

PATHOLOGY AND SURGICAL TREATMENT OF TUMORS.
By N. Senn, M. D., Ph. D., LL. D., Professor of Practice of Surgery and
of Clinical Surgery, Rush Medical College; Professor of Surgery, < hicago
Polyclinic; Attending Surgeon to Presbyterian Hospital; Surgeon-in-Chief,
St. Joseph's Hospital, Chicago. One volume of 710 pages, with 515
engravings, including full-page colored plates. Prices: Cloth, 36.00 net;
Half-Morocco, $7.00 net.

Books specially devoted to this subject are few, and in our text-books and

systems of surgery this part of surgical pathology is usually condensed to a de-
gree incompatible with its scientific and clinical importance. The author spent
many years in collecting the material for this work, and has taken great pains
to present it in a manner that should prove useful as a text-book for the .student,
a work of reference for the busy practitioner, and a reliable, safe guide for the
surgeon. The more difficult operations are fully described and illustrated. More
than one hundred of the illustrations are original, while the remainder were
selected from books and medical journals not readily accessible.

" The most exhaustive of any recent book in English on this subject. It is well illus-
trated, and will doubtless remain as the principal monograph on the subject in our language

for some years. The book is handsomely illustrated and printed and the author has

given a notable and lasting contribution to Mirgery." — Journal of American Medical Asso-
ciation, Chicago.

12 W. B. SAUNDERS'

MEDICAL DIAGNOSIS. By Dr. Oswald Vierordt, Professor of
Medicine at the University of Heidelberg. Translated, with additions,
from the Second Enlarged German Edition, with the author's permission,
by Francis H. Stuart, A. M., M. D. Third and Revised Edition. In
one handsome royal-octavo volume of 700 pages, 178 fine wood-cuts in
text, many of which are in colors. Prices: Cloth, $4.00 net; Sheep or
Half-Morocco, $5.00 net.

In this work, as in no other hitherto published, are given full and accurate
explanations of the phenomena observed at the bedside. It is distinctly a clin-
ical work by a master teacher, characterized by thoroughness, fulness, and accu-
racy. It is a mine of information upon the points that are so often passed over
without explanation. Especial attention has been given to the germ-theory as a
factor in the origin of disease.

This valuable work is now published in German, English, Russian, and
Italian. The issue of a third American edition within two years indicates the
favor with which it has been received by the profession.

THE PICTORIAL ATLAS OF SKIN DISEASES AND SYPHI-
LITIC AFFECTIONS. (American Edition.) Translation from
the French. Edited by J. J. Pringi.K, M. B., F. R. C. P., Assistant Phy-
sician to, and Physician to the department for" Diseases of the Skin at, the
Middlesex Hospital, London. Photo-lithochromes from the famous models
of dermatological and syphilitic cases in the Museum of the Saint-Louis
Hospital, Paris, with explanatory wood-cuts and letter-press. In 12 Parts,
at $3.00 per Part. Parts 1 to 8 now ready.

"The plates are beautifully executed." — Jonathan Hutchinson, M. D. (London
Hospital).

" The plates in this Atlas are remarkably accurate and artistic reproductions of typical
examples of skin disease. The work will be of great value to the practitioner and student."
— William Anderson, M. D. (St. Thomas Hospital).

" If the succeeding parts of this Atlas are to be similar to Part 1, now before us, we have
no hesitation in cordially recommending it to the favorable notice of our readers as one of
the finest dermatological atlases with which we are acquainted." — Glasgow Medical "Journal,
Aug., 1895.

" Of all the atlases of skin diseases which have been published in recent years, the present
one promises to be of greatest interest and value, especially from the standpoint of the
general practitioner." — American Medico-Surgical Bulletin, Feb. 22, 1896.

"The introduction of explanatory wood-cuts in the text is a novel and most important
feature which greatly furthers the easier understanding of the excellent plates, than which
nothing, we venture to say, has been seen better in point of correctness, beauty, and general
merit." — New York Medical Journal , Feb. 15, 1896.

" An interesting feature of the Atlas is the descriptive text, which is written for each picture
by the physician who treated the case or at whose instigation the models have been made.
We predict for this truly beautiful work a large circulation in all parts of the medical world
where the names St. Louis and Baretta have preceded it." — Medical Record, N. Y., Feb. 1,

CATALOGUE OF MEDICAL WORKS. 1 3

PRACTICAL POINTS IN NURSING. For Nurses in Private
Practice. By Emily A. M. Stoney, Graduate of the Training
for Nurses, Lawrence, Mass.; Superintendent of the Training-School for
Nurses, I arnej Hospital, South Boston, Mass. 456 pages, ham
illustrated with 73 engravings in the text, and 9 colored and half-tone
plates. Cloth. Price, 51.75 net

SECOND EDITION, THOROUGHLY REVISED.

In this volume the author explains, in popular language and in the si
possible form, the entire ranoe of private nursing as distinguished from hospital
nursing, and the nurse is instructed how best to meet the various em 1
medical and surgical cases when distant from medical or surgical aid or when
thrown on her own resources.

An especially valuable feature of the work will be found in the directions to
the nurse how to improvise everything ordinarily needed in the sick-room, where
the embarrassment of the nurse, owing to the want of proper appliances, is fre-
quently extreme.

The work has been logically divided into the following sections:

I. The Nurse: her responsibilities, qualifications, equipment, etc.
II. The Sick- Room: its selection, preparation, and management.

III. The Patient : duties of the nurse in medical, surgical, obstetric, and gyne-

cologic cases.

IV. Nursing in Accidents and Emergencies.
V. Nursing in Special Medical Cases.

VI. Nursing of the New-born and Sick Children.
VII. Physiology and Descriptive Anatomy.

The Appendix contains much information in compact form that will be found
of great value to the nurse, including Rules for Feeding the Sick; Reci]
Invalid Foods and Beverages; fables of Weights and Measures; Table for
Computing the Date of Labor; List of Abbreviations ; Dose-List; and a full
and complete Glossary of Medical Terms and Nursing Treatment.

"This is a well written, eminently practical volume, which covers the entire range of
private nursing as distinguished from hospital nursing, and instructs the nurse how hest to
meet the various emergencies which may .'.rise and how to prepare everything ordinarily-
needed in the illness of her patient." — American Journal of Obstetrics and Diseases of
W men and Children, Aug., 1896.

A TEXT-BOOK OF BACTERIOLOGY, including the Etiology and

Prevention of Infective Diseases and an account of Yeasts and Moulds,
Hiematozoa, a; rms. by EDGAR M. CrookSHANK, M. B.,

fessor of Comparative Pathology and Bacteriology, Kino- College, bond. .11.
A handsome octavo volume of 700 pages, with 273 engravings in the text,
and 22 original and colored plates. Price, S6.50 net.

This book, though nominally a Fourth Edition of Professor Crookshank's

" Manual <>i Bacteriology," 1- practically a new work, the old one having
been reconstructed, greatly enlarged, revised throughout, and largely rewritten,
forming a text-book for the Bacteriological Lalxjratory, for Medical < 'tn
Health, and for Veterinary Inspectors.

14 IV. B. SAUNDERS1

A TEXT-BOOK OF HISTOLOGY, DESCRIPTIVE AND PRAC-
TICAL. For the Use of Students. By Arthur Clarkson, M. B.,
C. M., Edin., formerly Demonstrator of Physiology in the Owen's College,
Manchester; late Demonstrator of Physiology in the Yorkshire College,
Leeds. Large 8vo, 554 pages, with 22 engravings in the text, and 174
beautifully colored original illustrations. Price, strongly bound in Cloth,
$6.00 net.

The purpose of the writer in this work has been to furnish the student of His-
tology, in one volume, with both the descriptive and the practical part of the
science. The first two chapters are devoted to the consideration of the general
methods of Histology ; subsequently, in each chapter, the structure of the tissue
or organ is first systematically described, the student is then taken tutorially over
the specimens illustrating it, and, finally, an appendix affords a short note of the
methods of preparation.

"We would most cordially recommend it to all students of histology." — Dublin Medical
Journal.

" It is pleasant to give unqualified praise to the colored illustrations ; . . . the standard is
high, and many of them are not only extremely beautiful, but very clear and demonstra-
tive. . . . The plan of the book is excellent." — Liverpool Medical Journal.

ARCHIVES OF CLINICAL SKIAGRAPHY. By Sydney Rowland,
B. A., Camb. A series of collotype illustrations, with descriptive text,
illustrating the applications of the New Photography to Medicine and Sur-
gery. Price, per Part, $1.00. Parts I. to V. now ready.

The object of this publication is to put on record in permanent form some of
the most striking applications of the new photography to the needs of Medicine
and Surgery.

The progress of this new art has been so rapid that, although Prof. Rontgen's
discovery is only a thing of yesterday, it has already taken its place among the
approved and accepted aids to diagnosis.

WATER AND WATER SUPPLIES. By John C. Thresh, D. Sc,
M. B., D. P. H, Lecturer on Public Health, King's College, London ;
Editor of the "Journal of State Medicine," etc. i2mo, 438 pages, illus-
trated. Handsomely bound in Cloth, with gold side and back stamps.
Price, $2.25 net.

This work will furnish any one interested in public health the information
requisite for forming an opinion as to whether any supply or proposed supply
is sufficiently wholesome and abundant, and whether the cost can be considered
reasonable.

The work does not pretend to be a treatise on Engineering, yet it contains
sufficient detail to enable any one who has studied it to consider intelligently any
scheme which may be submitted for supplying a community with water.

CATALOGUE OF MEDICAL WORKS. 15

DISEASES OF THE EYE. A Hand-Book of Ophthalmic Prac-
tice. By (.. I-:, de Schweinitz, M. I)., Professor ol Ophthalmology in

the Jefferson Medical College, Philadelphia, etc. A handsome royal-
octavo volume of 679 pages, with 256 fine illustrations, many of which arc-
original, and 2 chromo-lithographic plates. Prices: Cloth, 54.00 net;
Sheep or Half- Morocco, $5.00 net.

The object of this work is to present to the student, and to the practitioner
who is beginning work in the fields of ophthalmology, a plain description of the
optical defects and diseases of the eye. To this end special attention has been
paid to the clinical side of the question ; and the method of examination, the
symptomatology leading to a diagnosis, and the treatment of the various ocular
defects have been brought into prominence.

SECOND EDITION, REVISED AND CREATLY ENLARCED.

The entire book has been thoroughly revised. In addition to this general
revision, special paragraphs on the following new matter have been introduced :
Filamentous Keratitis, Blood-staining of the Cornea, Essential Phthisis Bulbi,
Foreign Bodies in the Lens, Circinate Retinitis, Symmetrical Changes at the
Macula Lutea in Infancy, Hyaline Bodies in the Papilla, Monocular Diplopia,
Subconjunctival Injections of Germicides, Infiltration-Anaesthesia, and Steriliza-
tion of Collyria. Brief mention of Ophthalmia Nodosa, Electric Ophthalmia,
and Angioid Streaks in the Retina also finds place. An Appendix has been
added, containing a full description of the method of determining the corneal
astigmatism with the ophthalmometer of Javal and Schiotz, and the rotations
of the eyes with the tropometer of Stevens. The chapter on Operations has
been enlarged and rewritten.

" A clearly written, comprehensive manual. . . . One which we can commend to students
as a reliable text-book, written with an evident knowledge of the wants of those entering upon
the study of this special branch of medical science." — Britis h Medical Journal.

" The work is characterized by a lucidity of expression which leaves the reader in no
doubt as to the meaning of the language employed . . . We know of no work in which
these diseases are dealt with more satisfactorily, and indications for treatment more clearly
given, and in harmony with the practice of the most advanced ophthalmologists." — Mari-
time Medical

" It is hardly too much to say that for the student and practitioner beginning the study of
Ophthalmology, it is the best single volume at present published." — Medical a

" The latest and one of the best books on Ophthalmology. The book is thoroughly up to
date, and is certainly a work which not only commends itself to the student, but is a ready
reference for the busy practitioner." — International Medical Review.

PROFESSIONAL OPINIONS.

"A work that will meet the requirements not only of the specialist, but of the general
practitioner in a rare degree. I am satisfied that unusual success awaits it."

W'111 i.\M Pbppbr, M. I>.
Provost and Professor of Theory and Practice of Medicine and Clinical Medicine
in the University of Pennsylvania.

" Contains in concise and reliable form the accepted views of Ophthalmic Science."

William THOMSON, M. D.,
Professor of Ophthalmology, Jefferson Medical College, Philadelphia, P*.

1 6 IV. B. SAUNDERS"

TEXT-BOOK UPON THE PATHOGENIC BACTERIA. Spe-
cially written for Students of Medicine. By Joseph McFarland,
M. D., Professor of Pathology and Bacteriology in the Medico-Chirurgical
College of Philadelphia, etc. 359 pages, finely illustrated. Price, Cloth,
$2.50 net.

The book presents a concise account of the technical procedures necessary in
the study of Bacteriology. It describes the life-history of pathogenic bacteria, and
the pathological lesions following invasion.

The work is intended to be a text-book for the medical student and for the
practitioner who has had no recent laboratory training in this department of medi-
cal science. The instructions given as to needed apparatus, cultures, stainings,
microscopic examinations, etc., are ample for the student's needs, and will afford
to the physician much information that will interest and profit him relative to a
subject which modern science shows to go far in explaining the etiology of many
diseased conditions.

The illustrations have been gathered from standard sources, and comprise the
best and most complete aggregation extant.

" It is excellently adapted for the medical students and practitioners for whom it is avowedly
written. . . . The descriptions given are accurate and readable, and the book should prove
useful to those for whom it is written. — London Lancet, Aug. 29, 1896.

" The author has succeded admirably in presenting the essential details of bacteriological
technics, together with a judiciously chosen summary of our present knowledge of pathogenic
bacteria. . . . The work, we think, should have a wide circulation among English-speaking
students of medicine." — N. Y. Medical Journal, April 4, 1896.

" The book will be found of considerable use by medical men who have not had a special
bacteriological training, and who desire to understand this important branch of medical
science." — Edinburgh Medical Journal , July, 1896.

LABORATORY GUIDE FOR THE BACTERIOLOGIST. By

Langdon Frothingham, M. D. V., Assistant in Bacteriology and Veteri-
nary Science, Sheffield Scientific School, Yale University. Illustrated.
Price, Cloth, 75 cents.

The technical methods involved in bacteria-culture, methods of staining, and
microscopical study are fully described and arranged as simply and concisely as
possible. The book is especially intended for use in laboratory work

" It is a convenient and useful little work, and will more than repay the outlay necessary
for its purchase in the saving of time which would otherwise be consumed in looking up the
various points of technique so clearly and concisely laid down in its pages." — American Alcd.-
Surg. Bulletin.

FEEDING IN EARLY INFANCY. By Arthur V. Meigs, M. D.
Bound in limp cloth, flush edges. Price, 25 cents net.

Synopsis : Analyses of Milk — Importance of the Subject of Feeding in Early
Infancy — Proportion of Casein and Sugar in Human Milk — Time to Begin Arti-
ficial Feeding of Infants — Amount of Food to be Administered at Each Feed-
ing— Intervals between Feedings — Increase in Amount of Food at Different
Periods of Infant Development — Unsuitableness of Condensed Milk as a Sub-
stitute for Mother's Milk — Objections to Sterilization or " Pasteurization " of
Milk — Advances made in the Method of Artificial Feeding of Infants.

CATALOGUE OF MEDICAL WORKS. \y

ESSENTIALS OF ANATOMY AND MANUAL OF PRACTI-
CAL DISSECTION, containing " Hints on Dissection ' By CHARLES
B. Nancrede, M. D., Professor of Surgery and Clinical Surgery in the
University of Michigan, Ann Arbor; Corresponding Member of the Royal
Academy of Medicine, Rome, Italy ; late Surgeon Jefferson Medical Col-
lege, etc. Fourth and revised edition. Post 8vo, over 500 pages, with
handsome full-page lithographic plates in colors, and over 200 illustrations.
Price : Extra Cloth or Oilcloth for the dissection-room, $2.(x> net.

Neither pains nor expense has been spared to make this work the most ex-
haustive yet concise Student's Manual of Anatomy and Dissection ever pub-
lished, either in America or in Europe.

The colored plates are designed to aid the student in dissecting the muscles,
arteries, veins, and nerves. The wood-cuts have all been specially drawn and
engraved, and an Appendix added containing 60 illustrations representing the
structure of the entire human skeleton, the whole being based on the eleventh
edition of Gray's Anatomy.

" The plates are of more than ordinary excellence, and are of especial value to students in
their work in the dissecting-room." — Journal of American Medical Association.

"Should be in the hands of every medical student." — Cleveland Medical Gazette.

"A concise and judicious work." — Buffalo Medical and Surgical Journal.

A MANUAL OF PRACTICE OF MEDICINE. By A. A. Stevens,
A. M., M. D., Instructor of Physical Diagnosis in the University of Penn-
sylvania, and Demonstrator of Pathology in the Woman's Medical College
of Philadelphia. Specially intended for students preparing for graduation
and hospital examinations, and includes the following sections : General
Diseases, Diseases of the Digestive Organs, Diseases of the Respiratory
System, Diseases of the Circulatory System, Diseases of the Nervou~
tern, Diseases of the Blood, Diseases of the Kidneys, and Diseases of the
Skin. Each section is prefaced by a chapter on General Symptomatology.
Post 8vo, 512 pages. Numerous illustrations and selected formula1.
Price, $2.50.

FOURTH EDITION, REVISED AND ENLARGED.

Contributions to the science of medicine have poured in so rapidly during the
last quarter of a century that it is well-nigh impossible for the student, with the
limited time at his disposal, to master elaborate treatises or to cull from them
that knowledge which is absolutely essential. From an extended experience in
teaching, the author has been enabled, by classification, to Ljroup allied symp-
toms, and by the judicious elimination of theories and redundant explanations
to bring within a comparatively small compass a complete outline of the prac-
tice of medicine.

W. B. SAUNDERS

MANUAL OF MATERIA MEDICA AND THERAPEUTICS.

By A. A. Stevens, A. M., M. D., Instructor of Physical Diagnosis in the
University of Pennsylvania, and Demonstrator of Pathology in the Woman's
Medical College of Philadelphia. 445 pages. Price, Cloth, #2.25.

SECOND EDITION, REVISED.

This wholly new volume, which is based on the last edition of the Pharma-
copeia, comprehends the following sections : Physiological Action of Drugs ;
Drugs; Remedial Measures other than Drugs; Applied Therapeutics; Incom-
patibility in Prescriptions; Table of Doses; Index of Drugs; and Index of
Diseases ; the treatment being elucidated by more than two hundred formulae.

" The author is to be congratulated upon having presented the medical student with as
accurate a manual of therapeutics as it is possible to prepare." — Therapeutic Gazette.

" Far superior to most of its class ; in fact, it is very good. Moreover, the book is reliable
and accurate." — New York Medical Journal.

" The author has faithfully presented modern therapeutics in a comprehensive work, . . .
and it will be found a reliable guide."— University Medical Magazine.

NOTES ON THE NEWER REMEDIES: their Therapeutic Ap-
plications and Modes of Administration. By David Cerna, M. D.,
Ph. D., Demonstrator of and Lecturer on Experimental Therapeutics in
the University of Pennsylvania. Post-octavo, 253 pages. Price, #1.25.

SECOND EDITION, RE-WRITTEN AND GREATLY ENLARGED.

The work takes up in alphabetical order all the newer remedies, giving their
physical properties, solubility, therapeutic applications, administration, and
chemical formula.

It thus forms a very valuable addition to the various works on therapeutics
now in existence.

Chemists are so multiplying compounds, that, if each compound is to be thor-
oughly studied, investigations must be carried far enough to determine the prac-
tical importance of the new agents.

" Especially valuable because of its completeness, its accuracy, its systematic consider-
ation of the properties and therapy of many remedies of which doctors generally know but
little, expressed in a brief yet terse manner." — Chicago Clinical Review.

TEMPERATURE CHART. Prepared by D. T. Laine, M. D. Size
8x 13%. inches. Price, per pad of 25 charts, 50 cents.

A conveniently arranged chart for recording Temperature, with columns for
daily amounts of Urinary and Fecal Excretions, Food, Remarks, etc. On the
back of each chart is given in full the method of Brand in the treatment of
Typhoid Fever.

CATALOGUE OF MEDICAL WORKS. 1 9

SAUNDERS' POCKET MEDICAL LEXICON; or, Dictionary of
Terms and Words used in Medicine and Surgery. By foHN M.
Keating, M. D., editor of"< ia ol Disi ol Children," etc. ;

author of the " New Prououncing Dictionary of Medicine;" and II.
Hamilton, author of " A New Translation of Virgil's .Encid into Eng-
lish Verse;" co-author of a " New Pronouncing Dictionary of Medicine."
A new and revised edition. 321110, 282 pages. Price, : Cloth, 75 cents;
Leather Tucks, $1.00.

This new and comprehensive work of reference is the out. ome of a demand
for a more modern handbook of it, class than tho market,

which, dating as they do from 1S55 to 1884, are ol but trifling use to the student
by their not containing the hundreds of new words now used in current litera-
ture, especially those relating to Electricity and Bacteriology.

*' Remarkably accurate in terminology, accentuation, and definition."— Journal of 'Amer-
ican Medical Association.

" Brief, yet complete .... it contains the very latest nomenclature in even the newest
departments of medicine." — New York Medical Record.

SAUNDERS' POCKET MEDICAL FORMULARY. By William
M. POWEI 1. M. D., Attending Physician to the Mercer House for Invalid
Women at Atlantic City. Containing 1750 Formula;, selected from several
hundred of the best known authorities. Forming a handsome and con-
venient pocket companion of nearly 300 printed page-, with blank leaves
for Additions; with an Appendix containing Posological Table, Formula;
and Doses for Hypodermatic Medication, Poisons and their Antidotes,
Diameters of the Female Pelvis and Fnetal Head, Obstetrical Table. Diet
List for Various Disease^. Material, and Drugs used in Antiseptic Surgery,
Treatment of Asphyxia from Drowning, Surgical Remembrancer, Tables
of Incompatibles, Eruptive Fevers, Weights and Measures, etc. Third
edition, revised and greatly enlarged. Handsomely bound in morocco,
with ,ide index, wallet, and flap. Price, 51.75 net.

A concise, clear, and correct record of the many hundreds of famous formulae
which are found scattered through the works of the most eminent physicians
and surgeons of the world. The work is helpful to the student and practitioner
alike, as through it they become acquainted with numerous formulae which are
not found in text-books, but have been collected from among the ri
Hon of the profession, college professors, and hospital physicians ana

"This little hook, that can be conveniently carried in the pocket, contains an immense
amount of material. It is very useful, and as the name of the author of each prescription is
given is unusually reliable." — New York Medical Record.

" Designed to be of immense help to the general practitioner in the exercise of his daily
calling." — Boston Medical and Surgical Journal.

20 W. B. SAUNDERS'

DISEASES OF WOMEN. By Henry J. Garrigues, A.M., M. D.,
Professor of Gynecology and Obstetrics in the New York School of Clinical
Medicine; Gynecologist to St. Mark's Hospital and to the German Dis-
pensary, New York City. In one handsome octavo volume of 728 pages,
illustrated by 335 engravings and colored plates. Prices: Cloth, $4.00 net;
Sheep or Half Morocco, $5.00 net.

A PRACTICAL work on gynecology for the use of students and practitioners,
written in a terse and concise manner. The importance of a thorough know-
ledge of the anatomy of the female pelvic organs has been fully recognized by
the author, and considerable space has been devoted to the subject. The chap-
ters on Operations and on Treatment are thoroughly modern, and are based
upon the large hospital and private practice of the author. The text is eluci-
dated by a large number of illustrations and colored plates, many of them being
original, and forming a complete atlas for studying embryology and the anatomy
of the female genitalia, besides exemplifying, whenever needed, morbid condi-
tions, instruments, apparatus, and operations.

Second Edition, Thoroughly Revised.

The first edition of this work met with a most appreciative reception by the
medical press and profession both in this country and abroad, and was adopted
as a text-book or recommended as a book of reference by nearly one hundred
colleges in the United States and Canada. The author has availed himself of
the opportunity afforded by this revision to embody (he latest approved advances
in the treatment employed in this important branch of Medicine. He has also
more extensively expressed his own opinion on the comparative value of the
different methods of treatment employed.

"One of the best text-books for students and practitioners which has been published in
the English language; it is condensed, clear, and comprehensive. The profound learning
and great clinical experience of the distinguished author find expression in this book in a
most attractive and instructive form. Young practitioners, to whom experienced consultants
may not be available, will find in this book invaluable counsel and help."

Thad. A. Reamy, M. D., LL.D.,

Professor of Clinical Gynecology , Medical College of Ohio ; Gynecologist to the Good
Samaritan and Cincinnati Hospitals.

A SYLLABUS OF GYNECOLOGY, arranged in conformity with
"An American Text-Book of Gynecology." By J. W. Long, M. D.,

Professor of Diseases of Women and Children, Medical College of Vir-
ginia, etc. Price, Cloth (interleaved), $1.00 net.

Based upon the teaching and methods laid down in the larger work, this will
not only be useful as a supplementary volume, but to those who do not already
posses? the text-book it will also have an independent value as an aid to the
practitioner in gynecological work, and to the student as a guide in the lecture-
room, as the subject is presented in a manner at once systematic, clear, succinct,
and practical.

CATALOGUE OF MEDICAL WORKS. 21

A MANUAL OF PHYSIOLOGY, with Practical Exercises. For

Students and Practitioners. By <i. N. STEWART, M. A., M. D . I

lately Examiner in Physiology, University of Aberdeen, and "f the New

Museums, Cambridge University; Professor of Physiology in i!

Reserve University, Cleveland, Ohio. Handsome octavi I 800

pages, with 278 illustrations in the text, ami 5 colored plati

Cloth, S3. 50 net.

" It will mike its way by sheer force of merit, and amply deserves to do so. It is one oj
the very best English text-books on the subject." — London Lancet.

"Of the many text-books of physiology published, we do not know of one that so nearly
comes up to the ideal as does Professor Stewart's volume." — British Medical Journal.

ESSENTIALS OF PHYSICAL DIAGNOSIS OF THE THORAX.
By ARTHUR M. CORWIN, A. M., M. 1)., Demonstrator of Physical Diaj

sis in the Rush Medical College, Chicago; Attending Physician to the
Central Free Dispensary, Department of Rhinology, Laryngology, and
Diseases of the Chest. 200 pages. Illustrated. Cloth, flexible covers.
Price, Si. 25 net.

SYLLABUS OF OBSTETRICAL LECTURES in the Medical
Department, University of Pennsylvania. By RICHARD C. Noi
A. M., M. D., Lecturer on Clinical and Operative Obstetrics, Unh

of Pennsvlvania. Third edition, thoroughly revised and enlarged. Crown
8vo. Price, Cloth, interleaved for notes, $2.00 net.

" This work is so far superior to others on the same subject that we take pleasure in call-
ing attention briefly to its excellent features. It covers the subject thoroughly, and will
prove invaluable both to the student and the practitioner. The author has introduced a
number of valuable hints which would only occur to one who was himself an experienced
teacher of obstetrics. The subject-matter is clear, forcible, and modern. We are especially
pleased with the portion devoted to the practical duties of the accoucheur, care of the child,
etc. The paragraphs on antisf-ptics are admirable; there is no doubtful tone in the^ direc-
tions given. No details are regarded as unimportant ; no minor matters omitted. We ven-
»ay that even the old practitioner will find useful hints in this direction which he can-
not afford to despise." — New York Medical Record.

A SYLLABUS OF LECTURES ON THE PRACTICE OF SUR-
GERY, arranged in conformity with " An American Text-Book
of Surgery." By X. SENN, M. D., Ph. D., Professor of Surgery in Rush
Medical College, Chicago, and in the Chicago Polyclinic. Price, $2.00.

This, the latest work of its eminent author, himself one of the contributors
to "An American Text Book of Surgery," will prove of exceptional value to
the advanced student who has adopted that work as his text-book. It i< not
only the syllabus of an unrivalled course of surgical practice, but it is .1'
epitome of or supplement to the larger work.

" The author has evidently spared no pains in makinc his Syllabus thoroughly comprehen-
sive, and has added new matter and alluded to the most recent authors •« Full
references are also given to all requisite details of surgical anatomy and pathology." — British
Medical Journal, London.

22 W. B, SAUNDERS'

AN OPERATION BLANK, with Lists of Instruments, etc. re-
quired in Various Operations. Prepared by W. W. Keen, M. D.,
LL.D., Professor of Principles of Surgery in the Jefferson Medical Col-
lege, Philadelphia. Price per Pad, containing Blanks for fifty operations,
50 cents net.

SECOND EDITION, REVISED FORM.

A convenient blank, suitable for all operations, giving complete instructions
regarding necessary preparation of patient, etc., with a full list of dressings and
medicines to be employed.

On the back of each blank is a list of instruments used— viz. general instru-
ments, etc., required for all operations ; and special instruments for surgery of
the brain and spine, mouth and throat, abdomen, rectum, male and female
genito-urinary organs, the bones, etc.

The whole forming a neat pad, arranged for hanging on the wall of a sur-
geon's office or in the hospital operating-room.

"Will serve a useful purpose for the surgeon in reminding him of the details of prepa-
ration for the patient and the room as well as for the instruments, dressings, and antiseptics
needed " — New Y01 k Medical Record

" Covers about all that can be needed in any operation."— American Lancet

"The plan is a capital one." — Boston Medical and Surgical yournal.

LABORATORY EXERCISES IN BOTANY. By Edson S. Bastin,
M. A., Professor of Materia Medica and Botany in the Philadelphia Col-
lege of Pharmacy. Octavo volume of 536 pages, 87 full-page plates. Price,
Cloth, $2.50.

This work is intended for the beginner and the advanced student, and it fully
covers the structure of flowering plants, roots, ordinary stems, rhizomes, tubers,
bulbs, leaves, flowers, fruits, and seeds. Particular attention is given to the gross
and microscopical structure of plants, and to those used in medicine. Illustra-
tions have freely been used to elucidate the text, and a complete index to facil-
itate reference has been added.

" There is no work like it in the pharmaceutical or botanical literature of this country, and
we predict for it a wide circulation." — American yournal of Pharmacy.

DIET IN SICKNESS AND IN HEALTH. By Mrs. Ernest Hart,
formerly Student of the Faculty of Medicine of Paris and of the London
School of Medicine for Women ; with an Introduction by Sir Henry
Thompson, F. R. C. S., M. I)., London. 220 pages ; illustrated. Price,
Cloth, $1.50.

Useful to those who have to nurse, feed, and prescribe for the sick. In
each case the accepted causation of the disease and the reasons for the special
diet prescribed are briefly described. Medical men will find the dietaries and
recipes practically useful, and likely to save them trouble in directing the dietetic
treatment of patients.

CATALOGUE OF MEDICAL WORKS. 2$

HOW TO EXAMINE FOR LIFE INSURANCE. By Joi
Keating, M.D., Fellow of the College of Physicians and Sui
Philadelphia; Vice-President of the American Pediatric Society; 1 •-
President of the Association of Fife Insurance Medical Directors. Royal
8vo, 211 pages, with two large half-tone illustrations, and a plate prepared
by Dr. McClellan from special dissections; also, numerous cuts to elucidate
the text. Second edition. Price, (huh, .S2.00 net.

"This is by far die most useful book which has yet appeared on insurance examination a
subject of growing interest and importance. Not the least valuable portion of the volume is
Part II., which consists of instructions issued to their examining physicians by twenty-four
representative companies of this country. As the proofs of these instructions were corrected
by the directors of the companies, they form the latest instructions obtainable. If for these
alone, the book should be at the right hand of every physician interested in this special branch
of medical science." — The Medical News, Philadelphia.

NURSING: ITS PRINCIPLES AND PRACTICE. By Isabel
Adams Hampton, Graduate of the New York Training School for
Nurses attached to Bellevue Hospital; Superintendent of Nurses and
Principal of the Training School for Nurses, Johns Hopkins Hospital,
Baltimore, Md. ; late Superintendent of Nurses, Illinois Training School
for Nurses, Chicago, 111. In one very handsome i2mo volume of 484
pages, profusely illustrated. Price, Cloth, S2.00 net.

This original work on the important subject of nursing is at once comprehensive
and systematic. It is written in a clear, accurate, and readable style, suitable
alike to the student and the lay reader. Such a work has long been a desidera-
tum with those entrusted with the management of hospitals and the instruction of
nurses in training-schools. It is also of especial value to the graduated nurse
who tlesires to acquire a practical working knowledge of the care of the sick
and the hygiene of the sick-room.

OBSTETRIC ACCIDENTS, EMERGENCIES, AND OPERA-
TIONS. By L. C'11. Boisliniere, M. D., late Emeritus Professor of

Obstetrics in the St. Louis Medical College. 381 pages, handsomely illus-
trated. Price, S2.00 net.

" For the use of the practitioner who, when away from home, has not the
opportunity of consulting a library or of calling a friend in consultation. He
then, being thrown upon his own resources, will find this book of benefit in
guiding and assisting him in emergencies."

INFANT'S WEIGHT CHART. Designed by J. P. CROZ1 r GRIFFITH,

M. D., Clinical Professor of Diseases of Children in the University of Penn-
sylvania. 25 charts in each pad. Price per pad, 50 cents net.

A convenient blank for keeping a record of the child's weight during the first
tw 1 years of life. Printed on each chart is a curve representing the average weight
of a healthy infant, so that any deviation from the normal can readil)

24 tV. B. SAUNDERS'

THE CARE OF THE BABY. By J. P. Crozer Griffith, M. D.,
Clinical Professor of Diseases of Children, University of Pennsylvania;
Physician to the Children's Hospital, Philadelphia, etc. 392 pages, with
67 illustrations in the text, and 5 plates. i2mo. Price, 51.50.

A reliable guide not only for mothers, but also for medical students and
practitioners whose opportunities for observing children have been limited.

" The whole book is characterized by rare good sense, and is evidently written by a mas-
ter hand. _ It can be read with benefit not only by mothers, but by medical students and by
any practitioners who have not had large opportunities for observing children." — American
yournal of Obstetrics.

THE NURSE'S DICTIONARY of Medical Terms and Nursing
Treatment, containing Definitions of the Principal Medical and Nursing
Terms, Abbreviations, and Physiological Names, and Descriptions of the
Instruments, Drugs, Diseases, Accidents, Treatments, Operations, Foods,
Appliances, etc. encountered in the ward or in the sick-room. Compiled
for the use of nurses. By Honnor Morten, author of " How to Become
a Nurse," "Sketches of Hospital Life," etc. i6mo, 140 pages. Price,
Cloth, $ 1. 00.

This little volume is intended for use merely as a small reference-book which
can be consulted at the bedside or in the ward. It gives sufficient explanation
to the nurse to enable her to comprehend a case until she has leisure to look up
larger and fuller works on the subject.

DIET LISTS AND SICK-ROOM DIETARY. By Jerome B. Thomas,
M. D., Visiting Physician to the Home for Friendless Women and Children
and to the Newsboys' Home ; Assistant Visiting Physician to the Kings
County Hospital ; Assistant Bacteriologist, Brooklyn Health Department.
Price, Cloth, $1.50 (Send for specimen List.)

One hundred and sixty detachable (perforated) diet lists for Albuminuria,
Anaemia and Debility, Constipation, Diabetes, Diarrhoea, Dyspepsia, Fevers,
Gout or Uric-Acid Diathesis, Obesity, and Tuberculosis. Also forty detachable
sheets of Sick-Room Dietary, containing full instructions for preparation of
easily-digested foods necessary for invalids. Each list is numbered only, the
disease for which it is to be used in no case being mentioned, an index key
being reserved for the physician's private use.

DIETS FOR INFANTS AND CHILDREN IN HEALTH AND
IN DISEASE. By Louis Starr, M. D., Editor of " An American
Text-Book of the Diseases of Children." 230 blanks (pocket-book size),
perforated and neatly bound in flexible morocco. Price, $1.25 net.

The first series of blanks are prepared for the first seven months of infant
life ; each blank indicates the ingredients, but not the quantities, of the food,
the latter directions being left for the physician. After the seventh month,
modifications being less necessary, the diet lists are printed in full. Formula
foj trie preparation of diluents and foods are appended.

Practical, Exhaustive, Authoritative.

SAUNDERS'

NEW AID SERIES OF MANUALS

FOR

Students and Practitioners.

Mr. SAUNDERS is pleased to announce as now ready his NEW AID
SERIES OF MANUALS for Students and Practitioners. As pub-
lisher of the Standard Series <u Question Compends, and through intimate
relations with leading members of the medical profession, Mr. Saunders has
been enabled to study progressively the essential desiderata in practical "self-
helps " for students and physicians.

This study has manifested that, while the published " Question Compends"'
earn the highest appreciation of students, whom they serve in reviewing their
studies preparatory to examination, there is special need of thoroughly reliable
handbooks on the leading branches of Medicine and Surgery, each subject
being compactly and authoritatively written, and exhaustive in detail, without
the introduction of cases and foreign subject-matter which so largely expand
ordinary text-books.

The Saunders Aid Series will not merely be condensations from
present literature, but will be ably written by well-known authors
and practitioners, most of them being teachers in representative
American Colleges. This nc~v series, therefore, will form an admirable
collection of advanced lectures, which will be invaluable aids to students in
reading and in comprehending the contents of " recommended " works.

Each Manual will further be distinguished by the beauty of the
by the quality of the paper and printing ; by the copious use of illustrations ;
by the attractive binding in cloth; and by their extremely low prii

-5

SAUNDERS' NEW AID SERIES OF MANUALS.

VOLUMES PUBLISHED.

PHYSIOLOGY. By Joseph Howard Raymond, A. M , M. D., Professor
of Physiology and Hygiene and Lecturer on Gynecology in the Long
Island College Hospital, etc. Price, $1.25 net.

SURGERY, General and Operative. By John Chalmers DaCosta,
M. D,, Demonstrator of Surgery, Jefferson Medical College, Philadelphia,
etc. Double number. Price, #$2.50 net.

DOSE-BOOK AND MANUAL OF PRESCRIPTION- WRITING.

By E. Q. Thornton, M. D., Demonstrator of Therapeutics, Jefferson
Medical College, Philadelphia. Price, $1.25 net.

MEDICAL JURISPRUDENCE. By Henry C. Chapman, M. D., Pro-
fessor of Institutes of Medicine and Medical Jurisprudence in the Jeffer-
son Medical College of Philadelphia, etc Price, #1.50 net.

SURGICAL ASEPSIS. By Carl Beck, M. D., Surgeon to St. Mark's
Hospital and to the German Poliklinik ; Instructor in Surgery, New York
Post-Graduate Medical School, etc. Price, $1.25 net.

MANUAL OF ANATOMY. By Irving S. Haynes, M. D., Adjunct
Professor of Anatomy and Demonstrator of Anatomy, Medical Department
of the New York University, etc. (Double number.) Price, $2.50 net.

SYPHILIS AND THE VENEREAL DISEASES. By James
Nevins Hyde, M. D., Professor of Skin and Venereal Diseases, and
Frank H. Montgomery, M. D., Lecturer on Dermatology and Genito-
urinary Diseases, in Rush Medical College, Chicago. (Double number.)
Price, $2.50 net.

PRACTICE OF MEDICINE. By George Roe Lockwood, M. D.,
Professor of Practice in the Woman's Medical College of the New
York Infirmary, etc. (Double number.) Price, $2.50 net.

OBSTETRICS. By W. A. Newman Dorland, M. D., Asst. Demonstrator
of Obstetrics, University of Pennsylvania ; Chief of Gynecological Dispen-
sary, Pennsylvania Hospital. (Double number.) Price, #2.50 net.

DISEASES OF WOMEN. By J. Bland Sutton, F. R. C. S., Assistant
.Surgeon to the Middlesex Hospital, and Surgeon to the Chelsea Hospital
for Women, London; and Arthur E. Giles, M. D., B. Sc. Lond.,
F. R. C. S. Edin., Assistant Surgeon to the Chelsea Hospital for Women,
London. 436 pages, handsomely illustrated. (Double number.) Price,
$2.50 net.

VOLUMES IN PREPARATION.
NERVOUS DISEASES. By Charles W. Burr, M. D., Clinical Pro-
fessor of Nervous Diseases, Medico-Chirurgical College, Philadelphia, etc.

NOSE AND THROAT. By D. Braden Kyll, M. D., Chief Laryngolo-
gist to St. Agnes' Hospital, Philadelphia; Instructor in Clinical Microscopy
and Assistant Demonstrator of Pathology in Jefferson Medical College.

*** There will be published in the same series, at short intervals, carefully
prepared works on various subjects, by prominent specialists.

SAUNDERS' QUESTION COMPENDS.

Arranged in Question and Answer Form.

THE LATEST, MOST COMPLETE, and BEST ILLUSTRATED
SERIES OF COMPENDS EVER ISSUED.

Now the Standard Authorities in Medical Literature

Students and Practitioners in every City of the United
States and Canada.

THE REASON WHY.

They are the advance guard of " Student's Helps " — that do HELP; they are
the leaders in their special line, well and authoritatively written by able men,
who, as teachers in the large colleges, ktto~w exactly what is wanted by a student
preparing for his examinations. The judgment exercised in the selection of
authors is fully demonstrated by their professional elevation. Chosen from the
ranks of Demonstrators, Quiz-master-, and Assistants, most of them have be-
come Professors and Lecturers in their respective colleges.

Each book is of convenient size (5x7 inches), containing on an average 250
pages, profusely illustrated, and elegantly printed in clear, readable type, on
fine paper.

The entire series, numbering twenty- four subjects, has been kept thoroughly
revised and enlarged when necessary, many of them being in their fourth and
fifth editions.

TO SUM UP.

Although there are numerous other Quizzes, Manuals, Aids. etc. in the mar-
ket, none of them approach the "Blue Series of Question Compends;" and
the claim is made for the following points of excellence :

1. Professional distinction and reputation of authors.

2. Conciseness, clearness, and soundness of treatment.

3. Size of type and quality of paper and binding.

Any of these Compends will be mailed on receipt of price see over
for List .

SAUNDERS' QUESTlON-COMPEiNl) SERIES.

Price, Cloth, $1.00 per copy, except when otherwise noted.

1. ESSENTIALS OF PHYSIOLOGY. 4th edition. Illustrated. Re-

vised and enlarged by H. A. Hare, M. D (Price, $1.00 net.)

2. ESSENTIALS OF SURGERY. 6th edition, with an Appendix on

Antiseptic Surgery. 90 illustrations. By Edward Martin, M. D.

3. ESSENTIALS OF ANATOMY. 5th edition, with an Appendix. 180

illustrations. By Charles B. Nancrede, M. D.

4. ESSENTIALS OF MEDICAL CHEMISTRY, ORGANIC AND

INORGANIC. 4th edition, revised, with an Appendix. By Law-
rence Wolff, M. D.

5. ESSENTIALS OF OBSTETRICS. 4th edition, revised and en-

larged. 75 illustrations. By W. Easterly Ashton, M. D.

6. ESSENTIALS OF PATHOLOGY AND MORBID ANATOMY.

7th thousand. 46 illustrations. By C. E. Armand Semple, M. D.

7. ESSENTIALS OF MATERIA MEDICA, THERAPEUTICS,

AND PRESCRIPTION-WRITING. 4th edition. By Henry
Morris, M. D.

8. 9. ESSENTIALS OF PRACTICE OF MEDICINE. By Henry

Morris, M. D. An Appendix on Urine Examination. Illustrated.
By Lawrence Wolff, M. D. 3d edition, enlarged by some 300 Es-
sential Formulae, selected from eminent authorities, by Wm. M. Powell,
M. D. (Double number, price $2.00.)

10. ESSENTIALS OF GYNECOLOGY. 4th edition, revised. With

62 illustrations. By Edwin B. Cragin, M. D.

11. ESSENTIALS OF DISEASES OF THE SKIN. 3d edition, re-

vised and enlarged. 71 letter-press cuts and 15 half-tone illustrations.
By Henry W. Stelwagon, M. D. (Price, $1.00 net.)

12. ESSENTIALS OF MINOR SURGERY, BANDAGING, AND

VENEREAL DISEASES. 2d edition, revised and enlarged. 78
illustrations. By Edward Martin, M. D.

13. ESSENTIALS OF LEGAL MEDICINE, TOXICOLOGY, AND

HYGIENE. 130 illustrations. By C. E. Armand Semple, M. D.

14. ESSENTIALS OF DISEASES OF THE EYE, NOSE, AND

THROAT. 124 illustrations. 2d edition, revised. By Edward
Jackson, M. D., and E. Baldwin Gleason, M. D.

15. ESSENTIALS OF DISEASES OF CHILDREN. Second edi-

tion. By William H. Powell, M. D.

16. ESSENTIALS OF EXAMINATION OF URINE. Colored

" Vogel Scale," and numerous illustrations. By Lawrence Wolff,
M. D. (Price, 75 cents.)

17. ESSENTIALS OF DIAGNOSIS. By S. Solis-Cohen, M. D., and

A. A. Eshner, M. D. 55 illustrations, some in colors. (Price, $1.50 net.)

18. ESSENTIALS OF PRACTICE OF PHARMACY. By L. E.

Sayre. 2d edition, revised.

20. ESSENTIALS OF BACTERIOLOGY. 3d edition. 82 illustra-

tions. By M. V. Ball, M. D.

21. ESSENTIALS OF NERVOUS DISEASES AND INSANITY.

48 illustrations. 3d edition, revised. By John C. Shaw, M. D.

22. ESSENTIALS OF MEDICAL PHYSICS. 155 illustrations. 2d

edition, revised. By Fred J. Brockway, M. D. (Price, $1.00 net.)

23. ESSENTIALS OF MEDICAL ELECTRICITY. 65 illustrations.

By David D. Stewart, M. D., and Edward S. Lawrance, M. D.

24. ESSENTIALS OF DISEASES OF THE EAR. By E. B. Glea-

son, M.D. 114 illustrations. Second edition, revised and enlarged.

CATALOGUE OF MEDICAL WORKS. 29

JUST PUBLISHED.

A TEXT-BOOK OF MATERIA MEDICA, THERAPEUTICS,
AND PHARMACOLOGY. Iiy George F. Butler, Ph. G., M I) .
Professor of Materia Medica and of Clinical Medicine in the College of
Physicians and Surgeons, Chicago; Professor of Materia Medica and Thera-
peutics, Northwestern University, Woman's Medical School, etc. 8vo, 858
pages. Illustrated. Prices: Cloth, $4.00 net; Sheep or Half-Morocco,
$5.00 net.

A clear, concise, and practical text-book, adapted for permanent reference no
less than for the requirements of the class-room. The arrangement is believed
to be at once the most philosophical and rational, as well as that best calculated
to engage the interest of those to whom the academic study of the subject is
wont to offer no little perplexity. Special attention has been given to the
Pharmaceutical section, which is exceptionally lucid and complete.

LECTURES ON RENAL AND URINARY DISEASES. By
Robert Saundby, M. D. Edin., Fellow of the Royal College of Physi-
cians, London, and of the Royal Medico-Chirurgical Society, Physician t<>
the General Hospital; Consulting Physician to the Eye Hospital and t<>
the Hospital for Diseases of Women ; Professor of Medicine in Mason
College, Birmingham, etc. 8vo, 434 pages, with numerous illustrations
and 4 colored plates. Price, Cloth, $2.50 net.

In these Lectures, which are a re-issue in one volume of the author's well-
known works on Bright's Disease and Diabetes, there is given, within a modest
compass, a review of the piesent state of knowledge of these important affect inns,
with such additions and suggestions as have resulted from the author's thirteen
years' clinical and pathological study of the subjects. The lectures have been
carefully revised and much new matter added to them. There has also been
added a section dealing witli " Miscellaneous Affections of the Kidney," making
the book more complete as a work of reference.

ELEMENTARY BANDAGING AND SURGICAL DRESSING,
with I Erections concerning the Immediate Treatment of < 'a>c> ol Emergency.
For the use of Dressers and Nurses. By WAJ 11 k I'vi. F. K. < '. S., late
Surgeon to St. Mary's Hospital, London. Small !2mo, with over 80 illus-
trations. Cloth, flexible covers. Price, 75 cents net.

This little book is chiefly a condensation of those portions of Pye's " Surgical
Handicraft" which deal with bandaging, splinting, etc., and of those which treat
of the management in the first instance of cases of emergency. Withm it-- own
limits, however, the book is complete, and it is hoped that it will prove extremely

useful to students when they begin their work in the wards and casualty rooms,
and useful also to surgical nurses and dressers.

" The directions are clear and the illustrations are good." — London I I
" The author writes well, the diagrams are clear, and the book itself is small and |>.>nat>le,
although the paper and type are good." — British Medical Journal.

JUST ISSUED. SOLD BY SUBSCRIPTION.

ANOMALIES

AND

CURIOSITIES OF MEDICINE.

BY

GEORGE M. GOULD, M. D., and WALTER L. PYLE, M. D.

Several years of exhaustive research ha\e been spent by the authors in the
great medical libraries of the United States and Europe in collecting the material

for this work, fledical literature of all ages and all languages has

been carefully searched, as a glance at the Bibliographic Index will show. The

facts, which will be of extreme value to the author and lecturer, have

been arranged and annotated, and full reference footnotes given, indicating
whence they have been obtained.

In view of the persistent and dominant interest in the anomalous and curious,
a thorough and systematic collection of this kind (the first of which the
authors have knowledge) must have its own peculiar sphere of usefulness.

As a complete and authoritative Book of Reference it will be of value
not only to members of the medical profession, but to all persons interested in
general scientific, sociologic, and medico-legal topics; in fact, the general inter-
est of the subject and the dearth of any complete work upon it make this
volume one of the most important literary innovations of the day.

An especially valuable feature of the book consists of the Indexing.
Besides a complete and comprehensive General Index, containing numerous
cross-references to the subjects discussed, and the names of the authors of the
more important reports, there is a convenient Bibliographic Index and a
Table of Contents.

The plan has been adopted of printing the topical headings in bold=
face type, the reader being thereby enabled to tell at a glance the subject-
matter of any particular pnragrnph or page.

Illustrations have been freely employed throughout the work, there being
165 relief cuts and 130 half-tones in the text, and 12 colored and half-tone full-
page plates — a total of over 320 separate figures.

The careful rendering of the text and references, the wealth of illustrations,
the mechanical skill represented in the typography, the printing, and the bind-
ing, combine to make this book one of the most attractive medical publications
ever issued.

Handsome Imperial Octavo Volume of 968 Pages.
PRICES: Cloth, $6.00 net; Half Morocco, $7.00 net.
3°

JUST ISSUED,

ANDERS' PRACTICE OF MEDICINE.

A Text-Book of the Practice of Medicine. Bj [auks M D PhD

LLD., Professor of the Practice ol Medicine and fClinical hirur-

gical College, Philadelphia. ( j

MACDONALDS SURGICAL DIAGNOSIS AND TREATMENT.

Surgical Diagnosis and Treatment. By J. W Macdonai d, M D..(

Medicine of the University i.f" Edinburgh : Professoi ' y and

of Clinical Surgery, Minneapolis College of Physicians and Surgeons. Cloth, $=,. a
Sheep or Half Morocco, $6.00 net.

MOORE'S ORTHOPEDIC SURGERY.

Orthopedic Surgery. By Iambs E. M is, M I) , Professor of Orthopedics and

Adjunct Professor ot Clinical Surgery, University of Minnes

and Surgery Octavo, 356 pages, handsomely illustrated. Clot) |

PENROSE'S DISEASES OF W^MEN.

A Text-Book of Diseases of Women. By Charles B. 1 I.D Ph D

Professor of Gynecology, University ol Pennsylvania: Surgeon to Gynecean Hospital,
Philadelphia. Octavo volume of 529 pages, handsomely illustrated. Price, £3.50 net.

MALLORY AND WRIGHT'S PATHOLOGICAL TECHNIQUE.

Pathological Technique. By Frank B Mallory, A M . M. I> . Asst. Pi

of Pathology, Harvard University Medical School; and JAMES H. W111.nr, A M.,
M. D , Instructor in Pathology. Harvard University Medical School. Octavo volume
of 306 pages, handsomely illustrated. Price, $2.50 net.

SENN'S GENITOURINARY TUBERCULOSIS.

Tuberculosis of the Genito-Urinary Organs, Male and Female. By Ni

Sinn, M. D., Ph.1> . LL D., Professor of the Practice of Surgery and of Clinical Sur-
gery, Rush Medical College, Chicago. Handsome octavo volume of 320 pages. Illus-
trated. Price, $3.00 net.

SUTTON AND GILES' DISEASES OF WOMEN.

Diseases of Women. By I Bland Sutton, F. R.t >-i;eon to Middlesex

Hospital, London; and ARTHUR E. GlLBS, M. D , U.S. , 1- R. C 5., Asst. Surgeon ic
Chelsea Hospital, London. 436 pages, handsomely illustrated. Price, $2.50 net.

IN PREPARATION.

VAN VALZAH AND NISBET'S DISEASES OF THE STOMACH.

Diseases of the Stomach. By William W. van Valzah, M I'., 1'r <fcssor of
General Medicine and Diseases of the Digestive System and the Blood. Nev
Polyclinic; and J. Douglas Nisbet, M.J>.. Adjunct Prof. ral Medicine

and Diseases of the Digestive .System and the Blood, V n \ rk Polyclinic.

AN AMERICAN TEXT-BOOK OF GENITO-URINARY AND SKIN DISEASES.
Edited by L. Bolton Has.,-. M l>., Late Professor of Genito-Urinary and Venerea]

Diseases. New York Post-Graduate Medical School and Hospital: and William A.
Hardaway, M. D., Professor f Diseases of the >kin, Missouri Med

AN AMERICAN TEXT-BOOK OF DISEASES OF THE EYE, EAR, NOSE, AND
THROAT.

Edited by G. E. dr Schweinitz, M. D . Professor of Ophthalmology in the Jefl
Medical College; and B. ALEXANDER Randall, M. D., Professi 1 f the

Ear in the University of Pennsylvania and in the Philai mic.

CHURCH AND PETERSON'S NERVOUS AND MENTAL DISEASES.

Nervous and Mental Diseases. By Archibald Church, Ml' I Men-

tal Diseases and Medical lurisprudence. Northwestern University M
Chicago; and Frederick "Plth;s. in, M !>., Clinical Professor ..t Menl
Woman's Medical College, New V..rk ; Chief of Clini . ■ " partment, College

of Physicians and Surgeons, New York.

HIRST'S OBSTETRICS.

A Text-Book of Obstetrics. By Barton Cooke Hirst, M. 1> , i

rics. University of Pennsylvania.

HEISLER'S EMBRYOLOGY.

A Text- Book of Embryology. By John C. Hbislbr, M I' Pn sector to the Pro-
fessor of Anatomy, Medical Department, University ol Penns)

XO IV READY, VOLUMES FOR 1800,189 7,189$.

S^TJISTID ZEISS'

AMERICAN YEAR-BOOK OF MEDICINE and SURGERY,

Edited by GEORGE M. GOULD, A. M., M. D.

Assisted by Eminent American Specialists and Teachers.

Notwithstanding the rapid multiplication of medical and surgical works,
still these publications fail to meet fully the requirements of the general physician,

z

inasmuch as he feels the need of something more than mere text -books of well- S»

g known principles of medical science. Mr. Saunders has long been impressed ^

^ with this fact, which is confirmed by the unanimity of expression from the pro- "

t fession at large, as indicated by advices from his large corps of canvassers. <5

fc This deficiency would best be met by current journalistic literature, but most |£

"£ practitioners have scant access to this almost unlimited source of information, «,

5; and the busy practiser has but little time to search out in periodicals the many 5

* interesting cases whose study would doubtless be of inestimable value in his £

5 practice. Therefore, a work which places before the physician in convenient fcu

^ form an epitomization of this literature by persons competent to pronounce itpon 5
•* «;

5 The Value of a Discovery or of a Method of Treatment «i.

> ...... 5

« cannot but command his highest appreciation. It is this critical and judicial 5

.2 function that will be assumed by the Editorial staff of the " American Year-

"g Book of Medicine and Surgery." <^

* It is the special purpose of the Editor, whose experience peculiarly qualifies 5*
5* him for the preparation of this work, not only to review the contributions to jjg

American journals, but also the methods and discoveries reported in the leading J

ii medical journals of Europe, thus enlarging the survey and making the work '

© characteristically international. These reviews will not simply be a series of

■* . . .2(5

5 undigested abstracts indiscriminately run together, nor will they be retrospective $

i of " news " one or two years old, but the treatment presented will be synthetic X:

•** and dogmatic, and will include only what is new. Moreover, through expert •

* condensation by experienced writers these discussions will be

Comprised in a Single Volume of about 1200 Pages.
The work will be replete with original and selected illustrations skilfully
reproduced, for the most part in Mr. Saunders' own studios established for the
purpose, thus ensuring accuracy in delineation, affording efficient aids to a right
comprehension of the text, and adding to the attractiveness of the volume.
Prices: Cloth, $6. 50 net ; Half Morocco, $7.50 net.

W. B. SAUNDERS, Publisher,

925 Walnut Street, Philadelphia.

SECOND EDITION,
REVISED AND GREATLY ENLARGED

Notes on the Newer Remedies

THERAPEUTIC APPLICATIONS
AND MODES OF ADMINISTRATION.

DAVID CERNA, M.D., Ph.D.,

Demonstrator of Physiology in the Medical Department of the
University of Texas ; formerly Demonstrator of and Lect-
urer on Experimental Therapeutics in the
University of Pennsylvania.

Post 8vo. 250 Paiges.

PRICE, $1.25.

W The work takes up in alphabetical order all the
Newer Remedies, giving their physical properties
— solubility — therapeutic application — administra-
tion and chemical formula.

It will, in this way, form a very valuable addition
to the various works on Therapeutics now in ex-
istence.

Chemists are so multiplying compounds that if
each compound is to be thoroughly studied, inves-
tigations must be carried far enough to determine
the practical importance of the new agents.

Brevity and conciseness compel the omission of
all biographical references.

MANUAL

MATERIA MEDICA

THERAPEUTICS.

BY

A. A. STEVENS, A. M., M. D.,

Instructor of Physical Diagnosis in the University of

Pennsylvania, and Demonstrator of Pathology in the

Woman's Medical College of Philadelphia.

435 Pages.
PRICE, CLOTH, $2.25.

This manual has been prepared especially
for students, with the hope that it may serve
as a thoroughly comprehensive outline of
modern therapeutics. The work, which is based'
on the 1890 edition of the U. S. Pharmacopoeia,
comprehends the following sections: Physio-
logical Action of Drugs ; Drugs ; Remedial
Measures other than Drugs ; Applied Thera-
peutics; Incompatibility in Prescriptions;
Table of Doses; Index of Drugs; and In-
dex of Diseases ; the treatment being eluci-
dated by more than two hundred formula.

Saunders* New Aid Series of Manuals.

NOW READY.

DOSE-BOOK

PREf

Dcm

(I

^VJ

Bve

E

0\

l?<t £

But

works c
to the i
form of
been \v:
hope tli
and coi
ject.

The \
(1890)
covers I
Prescrij
tiona to
«4tc), D