Handbook of physiology, for students and practitioners of medicine

Front matter

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Preface

This Handbook is the outcome of a desire to present to students a work that may serve to connect pure physiology with the physiology specially useful to physicians ; and I have endeavored to adapt it to the curricula of medical schools where the subject is taught in the English language. With this end in view, I undertook the now difficult task of selecting from the vast store of knowledge what I trust may be taken as a fairly symmetrical and comprehensive presentation of human physiology, not too voluminous for students or for ready reference by active practitioners. The subject has been treated from a medical standpoint; not unduly neglecting, it is hoped, pure physiology and biology.

In 1875 I published a Text-book of Hwnati Physiology, which was a condensation of a work in five volumes (i 866-1 874), entitled Physiology of Man. The second and third editions of that work contained such corrections and additions as it was possible to make in the electrotype plates. The book was rewritten for a fourth edition in 1888. During the twenty-five years from 1875 to 1900, about twenty-one thousand copies of the Text-book were distributed by sale. The advances in physiology since 1888 need not be indicated here. Since 1858 I have been actively engaged in teaching physiology to medical students, and since 1875 have used my own text-book. About five years ago, however, the book represented my teaching so imperfectly that I felt obliged to use more modern works for class recitations.

This volume represents the instruction in physiology now given at the Cornell University Medical College, somewhat expanded for more extended study and reference. It contains little of the text of former works, except parts relating to descriptive anatomy and established views that have become classic. Few unsettled questions, now under discussion, are considered at length ; but I have attempted to present what properly belongs to human physiology in a manner as plain and concise as possible.

Long experience as a teacher of undergraduates has convinced me that students can not be assumed to be sufficiently familiar with the descriptive anatomy and the histology of parts and organs to acquire vi PREFACE

easily a knowledge of their physiology ; and physiological chemistry is too closely connected with physiology to be neglected in a text-book. Again, the ordinary text-books on chemistry and physics contain little information in regard to the modern physical chemistry, ionization, dissociation, osmotic pressure, etc., all of which have important bearings on modern views in regard to physiological processes. While these subjects are by no means exhaustively considered, they are discussed at some length. Embryology might logically precede the study of physiology proper; but the difficulties of this subject are more easily surmounted by advanced than by first-year students, and for that reason it is considered last. Demonstrations, recitations, and laboratory work go hand in hand; but laboratory technique is a subject for practical instruction with the aid of special manuals. Descriptions of laboratory manipulations and illustrations of instruments and apparatus, therefore, are omitted.

I have not thought it desirable to give in extetiso minute details of what is called nerve-physiology, and only the general results of such work are presented. Full descriptions of electrical phenomena in nerve and muscle are to be found in laboratory manuals. Xo considerable account has been taken of mathematical formulae and calculations involved in certain special studies, such as physiological optics and acoustics. This would assume a knowledge of mathematics on the part of the student which usually does not exist. Still, the special senses are considered quite as fully as seems necessary, except for ophthalmologists and otologists. The same may be said of embryologv, a subject too large to be fully presented, except in special treatises. The plan of teaching and the arrangement of subjects do not involve a study of the nervous system in its relations to circulation, respiration, digestion and metabolism until the second year. Consideration of these relations is given mainly in the chapters on the nervous system, and they are briefly mentioned in the first part of the work.

For valuable aid in the important matter of illustration, I am under great obligations to professional friends ; but I alone must be held responsible for the text and for the arrangement of subjects.

In the matter of illustration a new departure is made which bids fair to revolutionize this important aid to the study of histology. After more than a year of experimentation, it has been found possible to reproduce, by what is known as the three-color process, stained histological objects, at all magnifications used in such work, as they actually appear under the microscope. This had already been done in 1895- 1896 by Dr. Edward Leaming, who photographed the objects, and Mr. Edward Bierstadt, who made gelatin-prints by the three-color process

PREFACE VU

of M. Ducos du Hauron ; but the cost of reproduction in this way is prohibitory as regards use in ordinary text-books. For several years before 1895, the printing, from ordinary process-plates, of reproductions of colored drawings or lithographs had been accomplished commercially. So far as I know, however, this has not been done before in photomicrography. The difficulties encountered in these efforts were considerable ; but they were at last overcome by the skilful and patient cooperation of Dr. Learning and of the American Colortype Company. Forty-eight illustrations of this kind are in the Atlas at the end of the book. With almost perfect fidelity as regards definition and color, they reproduce the objects used, and they may be studied as one would study with the microscope actual preparations. Of necessity, however, each picture represents a single field focussed for but one plane. The pictures taken from actual objects are supplemented in the Atlas with reproductions, by the same process, of plates selected from the histological atlas of Sobotta. These, though somewhat idealized, are introduced for the reason that they represent difficult objects, and some illustrate in a single page groups of objects that would require many more figures if made from actual specimens. Four figures, showing the first stages of cleavage of the ovum, have been reproduced, without reduction in size, from the original negatives taken by Dr. Learning for Professor Wilson's Atlas. These are printed in blue, although the original prints were in black and white.

It seemed to me very important to solve the problem of reproducing, at a moderate cost, stained objects in colors, for the reason that photomicrographs in black and white are nearly always inadequate and sometimes misleading. Compare, for example. Fig. 102, p. 464, in the text, with Fig. 4, Plate V, in the Atlas, both showing sections of the pancreas. For useful illustration, indeed, color-figures must be used, in the absence of study of actual objects, if for no other reason than that histological elements are so often differentiated by their affinities for various dyes and can be recognized only in stained preparations. Again, the student seldom sees in his laboratory work the appearances represented in books, even by the best and most costly colored drawings.

The technique employed in the photographic work is given by Dr. Leaming, in a note introductory to the Atlas. The negatives, taken through color-filters, were given, with the objects, to the Colortype Company, and put into the hands of their most intelligent workman, who was instructed first in the use of the microscope. The color-plates were made through a transparent screen with a ruling of one hundred and seventy-five lines to the inch. The etching was done in comparison with the actual objects, which were used as color-guides. This was the

Viii PREFACE

most difficult part of the process. The printing was done in the same way as in ordinary three-color work. Without the perfect negatives made by Dr. Learning through absolutely correct color-filters and the very intelligent and skilful work of the Colortype Company, the results obtained would not have been possible, — a fact emphasized by repeated failures during many months of experimentation. The cost of the three-color work has made but an insignificant addition to the price of the book, w^hile, it is believed, the color-illustrations have added greatly to its practical value.

Through the generous interest of the publishers in the manufacture of the book, unusual care was bestowed on the two hundred and forty-seven illustrations in the text. Of this number, one hundred and sixty-five were selected from three hundred and sixteen that appeared in a previous work. All, however, have been newly reproduced from the originals. Ninety of the one hundred and sixty-five are from Sappey, Bonamy and Beau, and Hirschfeld. These were imported from Paris in 1874. They are not only highly illustrative, but are fine examples of engraving on wood, now practically a lost art. Eighty-two figures, including four in colors, are either original or are taken from modern works. The latter could hardly be improved on by new drawings.

Special mention should be made of four figures reduced from photographs in Dalton's Topographical Anatomy of tJie Brain, and six figures reduced from photographs in the Atlas of the Karyokincsis and Fertilization of the Ovmn, by Professor Edmund B. Wilson, with the cooperation of Dr. Edward Leaming. A small edition of the late Professor Dalton's work was printed in 1885. It is now a rare book and little known ; but the prints represent the specimens with absolute fidelity, and are quite as useful for purposes of study as actual sections. The prints in Professor Wilson's Atlas are superb and unique. The figures from these works have not before been reproduced.

It may fairly be presumed that a considerable majority of Englishspeaking medical practitioners and students — for whom this work is intended — have been accustomed, by early education and common usage, to English weights and measures. To such readers, the metric system, now commonly used in scientific literature, frequently fails to convey a definite idea without a mental reduction to the familiar standards. For this reason, English weights and measures and the Fahrenheit scale are retained, and metric equivalents are given in parentheses. The micron (yoVo °^ ^ millimeter, or 2 s-^fo °^ ^^ inch), indicated by ^t, is frequently employed.

I am much indebted to colleagues and others for aid in preparing illustrations, and extend to them my grateful acknowledgments :

PREFACE IX

Dr. James Ewing, Professor of Pathology, and Dr. Jeremiah S. Ferguson, Instructor in Histology, of the Cornell University Medical College, assisted me greatly in the preparation and selection of histological objects. Professor Gage, of Cornell University, furnished the photograph of a human embryo, reproduced in Fig. 226. Dr. Israel Strauss, Instructor in Embryology in the Cornell University Medical College, furnished the sections of chick, reproduced in color in the Atlas. Without such valuable assistance, the illustration would have been more difficult and much less satisfactory.

AUSTIN FLINT.

New York, July, 1905.

Contents

PAGE

The ameba proteus — Protoplasm — The typical animal cell — Karyokinesis (Mitosis) — Prophases — Metaphase — Telophases — Amitosis — Ehrlich's side-chain hypothesis

— Immunity — Receptors — Passive and active immunity — Cytolysis — Alexins (Complements) — Amboceptors (Immune bodies) — Antibodies — Precipitins — Agglutins i

CHAPTER I The Blood

Importance of the blood — Quantity of blood — Opacity — Taste — Reaction — Specific gravit}' — Temperature — Color — Laking of blood — • Blood-corpuscles — Red corpuscles— Hemoglobin — Precipitin-test for blood — Development of red corpuscles

— Leucocytes — Lymphocytes — Blood-platelets — Plasma and serum — Fibrinogen

— Serum-globulin — Serum-albumin — Extractives and salts — Coagulation of the blood — Prothrombin and thrombin — Uses of coagulation ..... 14

CHAPTER II ClRCULATIOX OF THE BLOOD THROUGH THE HEART

Discovery of the circulation — Physiological anatomy of the heart — Tricuspid valve — Pulmonic valves — Mitral valve — Aortic valves — Movements of the heart — Cardiac cycle — Sounds of the heart — Frequency of the heart's action — Cause of the rhythmical contractions of the heart — Accelerator nerves — Direct inhibition of the heart

CHAPTER III Circulation of Blood in the Vessels

Circulation of blood in the arteries — Physiological anatomy of the arteries — Locomotion of the arteries and production of the pulse — Form of the pulse — Pressure of blood in the arteries — Pressure in different arteries — Influence of respiration — Influence of muscular action, etc. — Influence of hemorrhage, etc. — Rapidity of the current of blood in the arteries — Circulation of blood in the capillaries — Physiological anatomy of the capillaries — Pressure of blood in the capillaries — Rapidity of the capillary circulation — Relations of the capillary circulation to respiration — Causes of the capillary circulation — Influence of temperature on the capillary circulation — Circulation of blood in the veins — Structure and properties of the veins — Valves of the veins — Pressure of blood in the veins — Rapidity of the current of blood in the veins — Causes of the venous circulation — Influence of muscular contraction — Influence of aspiration from the thorax — Uses of the valves of the veins — Conditions that impede the venous circulation — Circulation in the cranial cavity — Circulation xii CONTENTS

PAGE in erectile tissues — Derivative circulation — Pulmonary circulation — Circulation in the walls of the heart — Migration and diapedesis — Rapidity of the circulation — Phenomena in the circulatory system after death ....... 50

CHAPTER IV Respiratory Movements

Physiological anatomy of the respiratory organs — Movements of respiration — Action of the diaphragm — Action of the muscles which raise the ribs — Scalene muscles — Intercostal muscles — Levatores costarum — Auxiliary muscles of inspiration — Expiration— Influence of the elasticity of the pulmonary structure and walls of the chest

— Action of muscles in expiration — Internal intercostals — Infracostales — Triangularis sterni — Obliquus externus — Obliquus internus — Types of respiration — Frequency of the respiratory movements — Respiratory sounds — Coughing, sneezing, sighing, yawning, laughing, sobbing and hiccough — Quantity of air changed in the respiratory acts — Diffusion of air in the lungs ........ 89

CHAPTER V Changes which the Air and the Blood undergo in Respiration

Composition of the air — Consumption of oxygen — Exhalation of carbon dioxide — Influence of age — Influence of sex — Influence of digestion — Influence of diet — Influence of muscular activity — Influence of moisture and temperature — Influence of the season of the year — Relations between the oxygen consumed and the carbon dioxide exhaled — Sources of carbon dioxide in the expired air — Respiratory quotient

— Exhalation of watery vapor — Exhalation of ammonia, organic matter etc. — Exhalation of nitrogen — Changes of the blood in respiration — Analysis of the blood for gases — Nitrogen of the blood — Oxygen of the blood — Carbon dioxide of the blood — Respiration by the tissues — Respiratory efforts before birth — Asphyxia . 116

CHAPTER VI Alimentation

Hunger and thirst — Nitrogenous alimentary substances — Non-nitrogenous alimentary substances — Carbohydrates — Dextrose — Levulose — Galactose — Saccharose — Lactose — Maltose — Starch — Glycogen — Cellulose, inosite and gums — The fats : triolein; tripalmitin; tristearin — Saponification — Emulsification — Inorganic alimentary substances — Water — Sodium chloride — Calcium phosophate — Iron — Alcohol — Coffee — Tea — Chocolate — Condiments and flavoring articles — The daily ration — Necessity of a varied diet — Meats — Bread — Potatoes — Milk — Eggs 1 38

CHAPTER VII Mastication, Insalivation and Deglutition

Physiological anatomy of the organs of mastication — The teeth — Enamel of the teeth —

— Dentin — Cement — Pulp-cavity — Superior maxillary bones — Inferior maxilla — Temporo-maxillary articulation — Muscles of mastication — Saliva — Parotid saliva

— Submaxillary saliva — Sublingual saliva — Secretions from the smaller glands of the mouth, tongue and pharynx — Mixed saliva — General properties and composition of the saliva — Uses of the saliva — Deglutition — Mechanism of deglutition — Protection of the posterior nares during the second period of deglutition — Protection

of the opening of the larynx and uses of the epiglottis in deglutition . . . .163

CONTEXTS xiii

CHAPTER VIII Gastric Digestiox PAGE

Physiological anatomy of the stomach — Peritoneal coat — Muscular coat — Mucous coat

— Glands of the stomach — Closed follicles — Gastric juice — Secretion of gastric • juice — Quantity of gastric juice — Properties and composition of gastric juice —

Saline constituents of the gastric juice — Pawlow's experiments on the gastric juice

— Action of the gastric juice on meats — Action on albumin, fibrin, casein and gelatin

— Action on vegetable nitrogenous substances — Peptones — Action on fats, sugars and amylaceous substances — Duration of stomach digestion — Conditions that influence stomach digestion — Movements of the stomach .,.,,, 185

Chapter IX

Physiological anatomy of the small intestine — Mucous membrane — Intestinal juice — Action of the intestinal juice in digestion — Pancreatic juice — Internal secretion by the pancreas — Composition and properties of the pancreatic juice — Action of the pancreatic juice on carbohydrates — Action of the pancreatic juice on proteids — Action of the pancreatic juice on fats — Action of bile in digestion — Movements of the small intestine — Physiological anatomy of the large intestine — Ileo-csecal valve

— Peritoneal coat — Muscular coat — Mucous coat — Processes of fermentation in the intestinal canal — Contents of the large intestine — Stercorin — Indol, scatol, phenol, cresol etc. — Movements of the large intestine — Defecation — Gases found

in the alimentary canal ............ 206

Chapter X

Absorption by bloodvessels — Absorption by lymphatic and lacteal vessels — Physiological anatomy of the lymphatic and lacteal vessels — Structure of the lymphatic and lacteal vessels — Lymphatic glands — Absorption of proteids by the lacteals — Absorption of sugar and salts by the lacteals — Absorption of water by the lacteals — Absorption by the skin — Absorption by the respiratory surface — Absorption from closed cavities, reservoirs of glands, etc. — Absorption of fats and insoluble substances — Influence of the condition of the blood and of the vessels on absorption — Influence of the nervous system on absorption — Osmosis — Mechanism of the passage of liquids through membranes — Osmotic pressure — Lymph and chyle — Properties and composition of lymph — Corpuscular elements of the lymph — Origin and uses of the lymph — Properties and composition of chyle — Composition of chyle ^Microscopical characters of the chyle — Movements of the lymph and chyle ..... 240

CHAPTER XI Secretion

Classification of the secretions — Mechanism of the production of the true secretions — Mechanism of the production of the excretions — Influence of the composition and pressure of the blood on secretion — Influence of the ner\'ous system on secretion — Paralytic secretion by glands — Anatomical classification of glandular organs — Secreting membranes — Follicular glands — Tubular glands — Racemose glands, simple and compound — Ductless, or blood-glands — Secretions and excretions — Synovial membranes and synovia — Mucous membranes and mucus — Mechanism of the secrexiv CONTENTS tion of mucus — Composition and varieties of mucus — General uses of mucus — Physiological anatomy of the sebaceous, ceruminous and Meibomian glands — Ordinary sebaceous matter — Smegma of the prepuce and labia minora — Vernix caseosa

— Cerumen — Mammary secretion — Mechanism of the secretion of milk — General conditions which modify the lacteal secretion — Properties and composition of milk

— Microscopical characters of milk — Composition of the milk — Colostrum — Lacteal secretion in the newly-born ........... 268

CHAPTER XII Excretion by the Skin

Physiological anatomy of the skin — Layers of the skin — The corium, or true skin — The epidermis — Physiological anatomy of the nails — Physiological anatomy of the hairs

— Roots of the hairs, and hair-follicles — Growth of the hairs — Sudden blanching of the hair — Uses of the hairs — Perspiration — Quantity of cutaneous exhalation — Properties and composition of the sweat ......... 3°5

CHAPTER XIII Excretion by the Kidneys

Physiological anatomy of the kidneys — Pyramidal substance — Cortical substance — Tubes of the cortical substance — Narrow tubes of Henle — Distribution of bloodvessels in the kidney — Mechanism of the production and discharge of urine — Influence of blood-pressure, the nervous system etc., on the secretion of urine — Physiological anatomy of the urinary passages — Mechanism of the discharge of urine — Properties and composition of the urine — Urea — Origin of urea — Influence of the ingesta on the composition of the urine and on the discharge of nitrogen — Influence of muscular exercise on the discharge of nitrogen — Uric acid and its compounds — Hippuric acid, hippurates and lactates — Calcium oxalate — Xanthin, hypoxanthin, leucin, tyrosin and taurin — Fatty matters — Inorganic constituents of the urine — Chlorides

— Sulphates — Phosphates — Water as a product of excretion — Variations in the composition of the urine — Variations with age and sex — Influence of mental exertion— Internal secretion — Work of the kidneys 322

Chapter XIV

Physiological anatomy of the liver — Branches of the portal vein, the hepatic artery and the hepatic duct — Interlobular vessels — Structure of a lobule — Arrangement of the bile-ducts in the lobules — Anatomy of the excretory passages — Gall-bladder, cystic and common ducts — Chemistry of the liver — Nerves and lymphatics of the liver — . Mechanism of the secretion of bile — Quantity of bile — Uses of the bile — Properties and composition of the bile — Biliary salts — Cholesterin and stercorin — Bilirubin — Tests for bile — Excretory action of the liver — Origin of cholesterin — Formation of glycogen in the liver — Conditions that influence the quantity of sugar in the blood

— Ductless glands and internal secretion — Suprarenal capsules — Cortical substance

— Medullary substance — Vessels and nerves — Chemistry of the suprarenal capsules

— Addison's disease — The spleen — Fibrous structure — Malpighian bodies — Spleen-pulp — Bloodvessels, nerves and lymphatics — Chemical constitution — Variations in volume — Extirpation — Thyroid gland — Structure — Vessels and nerves — Myxoedema — Thymus gland — Pituitary body and pineal gland — Acromegaly and giantism

— Internal secretion by the testes and ovaries 355

CONTENTS XV

CHAPTER XV Metabolism — Nutrition — Animal Heat and Force PAGE

Action of glandular cells — Metabolism, anabolism and katabolism — General nutrition — Luxus-consumption — Isodynamic values of foods — Animal heat and force — Limits of variations in the normal temperature in man — Variations in different parts of the body — Variations at different periods of life — Variations at different times of the day — Influence of exercise etc., on the heat of the body — Influence of the nervous system on the production of animal heat (heat-centres) — Mechanism of the production of animal heat — Equalization of the animal temperature — Relations of heat to force 392

CHAPTER XVI Muscular Movements

Amorphous contractile substance and ameboid movements — Ciliary movements — Movements due to elasticity — Elastic tissue' — Muscular movements — Contraction of involuntary muscular tissue — Physiological anatomy of the voluntary muscular tissue

— Connective tissue — Bloodvessels and lymphatics — Connection of the muscles with the tendons — Chemical composition of the muscles — Physiological properties of the muscles — Elasticity of muscles — Muscular tonicity — Sensibility of the muscles

— Muscular contractility and excitability — Muscular contraction — Changes in the form of fibres during contraction — Rigor mortis — Passive organs of locomotion — Physiological anatomy of the bones — Lacunae — Canaliculi — Bone-cells or corpuscles— Marrow of the bones — Periosteum — Physiological anatomy of cartilage

— Cartilage-cavities — Cartilage-cells — Elastic cartilage and fibro-cartilage . .412

Chapter XVII

Physiological anatomy of the vocal organs — Muscles of the larynx — - Crico-thyroid muscles— Arytenoid muscle — Lateral crico-arytenoid muscles — Thyro-arytenoid muscles

— Mechanism of the production of the voice — Movements of the glottis during phonation — Action of the intrinsic muscles of the larynx in phonation — Action of accessory vocal organs — Laryngeal mechanism of the vocal registers — Vocal registers in the male — Vocal registers in the female — Mechanism of speech — Vowels — Consonants— The phonograph and telephone ......... 435

CHAPTER XVIII Structure and Properties of the Nervous System

Divisions and structure of the nervous tissue — Medullated nerve-fibres — Xon-medullated nerve-fibres — Gelatinous nerve-fibres (fibres of Remak) — Accessory anatomical elements of the nerves — Branching and course of the nerves — Termination of nerves in voluntary muscles — Termination of nerves in glands — Modes of termination of sensory nerves — Corpuscles of Vater, or of Pacini — Tactile corpuscles — End-bulbs

— General mode of termination of the sensory nerves — -Structure of the ner\'e-centres

— Nerve-cells — Nissl's granules — The neuron — Accessory anatomical elements of the nerve-centres — Degeneration and regeneration of nerves — Motor and sensory nerves — Mode of action of the motor nerves — Associated movements — Mode of action of the sensory nerves — Physiological differences between motor and sensory xvi ' CONTENTS

PAGE

nerves — Nervous excitability and conductivity — Rapidity of nervous conduction — Personal equation — Action of electricity on the nerves — Law of contraction — Electric current from the exterior to the cut surface of a nerve — Electrotonus, anelectrotonus and catelectrotonus .......... 455

CHAPTER XIX Spinal Nerves — Motor Cranial Nerves

Spinal nerves — Cranial nerves — Motor oculi communis (third nerve) — Physiological anatomy — Properties and uses of the motor oculi communis — Patheticus, or troch- Icaris (fourth nerve) — Physiological anatomy — Properties and uses of the patheticus

— Motor oculi externus, or abducens (sixth nerve) — Physiological anatomy — Properties and uses of the motor oculi communis — Nerve of mastication (the small, or motor root of the fifth nerve) — Physiological anatomy — Properties and uses of the nerve of mastication — Facial, or nerve of expression (seventh nerve) — Physiological anatomy — General properties of the facial — Uses of branches of the facial given off within the aqueduct of Fallopius — Uses of the chorda tympani — Influence of certain branches of the facial on the movements of the palate and uvula — Uses of the external branches of the facial — Spinal accessory (eleventh nerve) — Physiological anatomy — Properties and uses of the spinal accessory — Uses of the internal branch from the spinal accessory to the pneumogastric — Influence of the internal branch of the spinal accessory on deglutition — Influence of the spinal accessory on the heart

— Uses of the external, or muscular branches of the spinal accessory — Sublingual (twelfth nerve) — Physiological anatomy — Properties and uses of the sublingual . 492

CHAPTER XX Trifacial Nerve — Pneumogastric Nerve

Trifacial (large root of the fifth nerve) — Physiological anatomy — Properties and uses of the trifacial — Immediate effects of division of the trifacial — Remote effects of division of the trifacial — Pneumogastric (tenth nerve) — Physiological anatomy — Properties and uses of the auricular nerves — Properties and uses of the pharyngeal nerves

— Properties and uses of the superior laryngeal nerves — Properties and uses of the inferior, or recurrent laryngeal nerves — Properties and uses of the cardiac nerves — Depressor nerve — Properties and uses of the pulmonary nerves — Effects of division of the pneumogastrics on respiration — Effects of faradization of the pncumogastrics on respiration — Properties and uses of the oesophageal nerves — Properties and uses of the abdominal nerves — Influence of the pneumogastrics on the liver — Influence of the pneumogastrics on the stomach and intestines — Effects of faradization — Influence of section of the pneumogastrics on the movements of the stomach — Influence

of the pneumogastrics on the small intestine ........ 521

Chapter XXI

Membranes of the encephalon and spinal cord — Cephalo-rachidian liquid — Physiological anatomy of the spinal cord — Columns of Tiirck — Crossed pyramidal tracts — Anterior ground columns — Lateral bundles — Ascending and descending cerebellar fasciculi — Direct cerebellar fasciculi — Columns of Burdach — Columns of Goll — Directions of nerve-fibres in the cord — General properties of the spinal cord — Relations of the posterior white columns of the cord to muscular coordination — • Nerve-centres in the spinal cord — Reflex action of the spinal cord — Reflexes in man 545

CONTENTS xvii

CHAPTER XXII The Cerebrum and the Basal Ganglia PAGE

Weights of the encephalon and of certain of its parts — The cerebral hemispheres — Cerebral convolutions — Basal ganglia — Corpora striata, optic thajami and internal capsule — Tubercula quadrigemina — Crura cerebri — Pons Varolii — Directions of fibres in the cerebrum — Fibres connecting the cerebrum with the cerebellum — Fibres connecting the two sides of the brain — Fibres connecting different cerebral convolutions on the same side (association fibres) — Fibres connecting the brain with the spinal cord — Cerebral localization — Motor cortical zone (Rolandic area) — General uses of the cerebrum — Extirpation of the cerebrum — Comparative development of the cerebrum in the lower animals — Development of the cerebrum in different races of men and in different individuals — Facial angle — Pathological observations — Reaction-time — Centre for the expressions of ideas in language .... 565

CHAPTER XXIII The Cerebellum and the Bulb

The cerebellum — Physiological anatomy — Extirpation of the cerebellum — Pathological observations — The bulb — Physiological anatomy — Uses of the bulb — Nerve-centres in the bulb — Respiratory centre — Vital point (so called) — Rolling and turning movements following injury of certain parts of the encephalon (forced movements) . 592

CHAPTER XXIV Sympathetic System — Sleep

Cranial ganglia — Cervical ganglia — Thoracic ganglia — Ganglia in the abdominal and the pelvic cavities — General properties of the sympathetic ganglia and nerves — Direct experiments on the sympathetic — Vasomotor centres and nerves — Reflex vasomotor phenomena — Vaso-inhibitory nerves — -Trophic centres and nerves — Sleep — Dreams — Condition of the brain and nervous system during sleep . . 606

CHAPTER XXV Sense of Touch — Olfaction — Gustation

Muscular sense — Sense of touch — Appreciation of temperature — Olfaction — Olfactory (first nerve) — Properties and uses of the olfactorj' nerves — Mechanism of olfaction — Relations of olfaction to the sense of taste — Gustation — Nerves of taste — Chorda tympani — Glosso-pharyngeal (ninth nerve) — General properties of the glosso-pharyngeal — Relations of the glosso-pharyngeal to gustation — Mechanism of gustation— Physiological anatomy of the organs of taste — Taste-beakers . . . 625