INDEX

Absorption from alimentary canal, 129

Accelerator nerves of heart, 237

Accommodation of the eye for distance, 391

for light, 390

Acromegaly, 93

Addison’s disease, 91

Adrenalin, action on the kidney, 209

formed in suprarenal capsule, 92

Air, quantity inspired, 173

quantity needed by individual, 191

Air-cells of lungs, 168

Albumin made by plants, 12

Alcohol, effect on nerve conduction, 301

Alimentary canal, morphology of, 98

nerves of, 104

Altitude, highest, attained by climbers, 187

Alveoli of lungs, their number, 169

Amides produced from proteins, 119

Amœba, irritability of its protoplasm, 10

Amyl nitrite, effect on vascular system, 237

Anæmia, treatment with iron, 67

Anæsthetics, influence on protoplasm, 11

Analysis by animals, 12

Angina pectoris, 237

Angler fish, its nerve-cells, 31

Animal machine and its driver, 354, 358

Animals, hunting versus hunted, 366

not reflex machines, 358

relative insensibility to the knife, 361

Antitoxins, formation by protoplasm, 20

Aorta, diameter of, 232

Aphasia, 352

Apnœa, condition of arrested respiration, 181

Appendicitis, increased frequency of, 101

Appetite, a safe guide, 114

Arteries, blood-pressure in, 234, 239

structure of wall of, 233

Artificial respiration, 183

Asphyxia, 182

Association-zones in the cortex of the great brain, 348

Asthma, due to reflex contraction of small bronchi, 167

Astigmatism, correction by glasses, 393

due to modern print, 269

Attention, effect of, in heightening pain, 361

Bacteria, diminution of number in intestine on milk diet, 138

of alimentary canal, 135

of Bulgarian sour milk, 138

of the River Ganges, 141

in an infant’s intestine, 136

their rôle in nature, 20

Balance-sheet of body, how drawn up, 149

Balloon, highest altitude attained in, 187

Basket-cells in nervous system, 324, 340

Bat’s squeak, number of vibrations, 418

Bats, flight not dependent on vision, 381

Beats in music, explanation of, 407

Beetle, muscle of, 261

Belladonna, physiological action, 109

Bile, composition, 117

function in regard to absorption of fat, 133

relation to digestion, 117

Bile-pigment, origin from hæmoglobin, 69, 82, 118

Bioplasm, the essential substance of a living cell, 148

Birds, sense of hearing of, 410

Blind spot, how filled in, 395

Blisters, 41

Blood, amount ejected by heart, 219

circulation-time, 219

composition of, 59

gases of, amount, 190

tension, 61

lodged in abdominal veins, 234, 236

Blood-corpuscles, cellular nature, 28

life-story, 62

number, 61

origin, 63, 64

structure, 60

Blood-platelets, 74

Blood-poisoning, 57

Blushing, 243

Bowman’s description of kidney, 200

discs in muscle, 259

Brain. Cf. Cerebellum, Cortex of cerebrum

blood-supply of, 352

Bread, digestion of, 120

Breathing, mechanism of, 171

Bruises, explanation of play of colours, 69

Bulgarian milk-germ, 138

Capillary vessels, circulation of blood in, 232

migration of leucocytes from, 232

structure of their walls, 38

Carbohydrate foods, chemical composition, 147

Carbonic acid, carried by blood, 60

liberation in lungs, 61, 189

Carbonic oxide, compound with hæmoglobin, 187

Carnivora, absorption of fat from alimentary canal of, 133

Cartilage, growth, 28

Catalysis, 17

Cell theory, 26

Cells, constituent parts, 26, 28

size, 30

specialization of function in, 35

Cells of Purkinje in the cerebellum, 303, 340

Cellulose, digestion of, 137

Cerebellum, cases of deficiency of, 341

connections with cerebro-spinal axis, 340

development of granules of, 299, 303

lobes, 338

minute anatomy, 339

phylogeny, 338

relation to tone of muscles, 342

Cerebral hemisphere, an outgrowth towards olfactory pit, 334

in animals with various sensory endowments, 349

Cerebro-spinal fluid, 50

Chemical activity of protoplasm, 12

messengers, 89, 123

processes in plants, 15

Chemiotaxis of leucocytes, 56, 364

Children, brain in, 346

development of astigmatism in eyes of, 269

Chill, catching a, 242

Chloroform. Cf. Anæsthetics

Cholesterin, 118

Chromatolysis in nerve-cells, 320

Chrome-silver method of colouring nerve-tissue, 293

Chyme, food converted into, 126

Circulation of the blood, 218

Circulation-time, 219

Cirrhosis of liver, 42

Coagulation of blood, 69

Cochlea, anatomy, 413

Cockney dialect, the degradation of vowel-sounds, 439

Coke-fire, poisonous fumes from, 186

Cold-spots in skin, 429

Collaterals of nerves, 297

Colon, length and disposition of, 101

Colour-blindness, 385

Colour-vision, 385

Colours, reason for apparent fading in twilight, 378

Conductivity of protoplasm, 248

Consciousness, does not come within physiological investigation, 360

its part in animal life, 359

Control experiments, their value, 72

Convolutions of brain, 345

Cooking, effect upon digestibility of meat, 120

Corneal epithelium, sensitiveness of, 424

Corpus striatum of brain, 344

Cortex of cerebrum, discovery of excitability of, 344

fissures and convolutions, 345

functional areas, 352

myelination of its fibres, 345

sensory and association areas, 346

structure of, 347

variations in different animals, 349

Corti, organ of, its structure, 414

theories of function of, 416

Coughing, mechanism of, 180

Crayfish, tone of claw-muscle of, 273

Cretinism, 85, 90

Cricket, chirp of, 261

Crypts of Lieberkühn, 103

Curdling of milk, 75

Dancing, association of sound with movement, 422

Day’s work, food required for, 151

Deafness due to sore throat, 412

Degeneration of nerves after section, 326

Depressor nerve of the heart, 237

Diabetes, excretion of more carbohydrate than contained in food, 143

Dialysis, explanation of the process, 40, 128

Diaphragm, function in respiration, 171

Diastases, destructive ferments, 18

Diet, limits of possible variations in, 153

of labouring classes, 152

Digestibility of bread, meat, fish, etc., 120, 125

Digestion, mechanism of, 96

vascular changes during, 235

waits on appetite, 114

Digitalis, action on heart and kidney, 209

Diphtheria, antitoxin of, 20

Diuretics, 209

Dog’s sense of smell, 370

Dreams, theory of, 362

Dropsy, 42

Drowning, resuscitation from, 183

Drugs, physiology of, 95

Ductless glands, 94

Dyspnœa, difficult respiration, 181

Ear, anatomy, 411

bones of, 412

differentiation into separate sense-organs, 410

in fishes, 410

phylogeny, 409

Eel’s blood injected into mammal, 20

Effector, an organ which exhibits change in response to stimulation, 253

Egg-albumin destroyed by blood, 19

Electric organs, 288

phenomena of muscles, 279

Emotions, their relation to vaso-motor changes, 242

Energy, expended by body, 151

source of the body’s, 152

of stimulus compared with energy of muscular response, 254

Engines, body compared with, 152, 256

Epiglottis during swallowing, 433

Equilibrium, maintenance of, in walking, 342

Erepsin, ferment of intestinal juice, 119

Errors of sensory judgment, 402

Excretion, 195

Eye, accommodation for distance, 391

adaptation for darkness, 390

blind spot, 394

optical defects of, 393

phylogeny, 334

refractive media, formation of image by, 391

Eyeball, abnormalities in shape of, 392

anatomy, 373

development, 374

muscles of, indefatigable, 269

Fat, absorption of, 131, 132

accumulation of, relation to foods consumed, 144

chemistry, 132

digestion, 133

laid down in connective tissues, 145

stored in liver, 145

Fatigue, causes of, 45, 268

Fermentation, 16

Ferments, chemical nature, 18

classification, 16, 18

physiological importance, 18

Fibrin of blood, its antecedents, 75

Fireflies, source of their light, 291

Fish, sense of smell of, 365

supposed to be frightened by noise, 410

Flatulence, cause of, 114, 125, 136

Foods, classification, 142

history of, after absorption, 142

relative value, 147, 151, 153, 157

residue after digestion and absorption, 194

Foramen ovale of heart, sometimes perforate, 218

Frigate-bird, turbinate bones of, 166

Frog, supposed to be found entombed in rock, 164

Functional interdependence of organs, 94

Functions transferred to other organs, 87

Gall-stones, cause of formation of, 118

Galvani’s observation of contraction of a frog’s muscles, 277

Ganges, purifying water of, 138

Ganglia of sympathetic chain, function, 325

Ganglion-cells of retina, 376

spinal, 299, 333

Gaseous tension, meaning of expression, 188

Gases of blood, their exchange in the lungs, 184

Gastric glands, structure, 123

juice, amount secreted, 114

composition, 114

digestive action, 115

Gelatin as article of diet, 158

Giant cells, 65

Glands, vaso-motor nerves of, 109, 241

Glycogen, formula, 147

as muscle food, 148

stored in liver, 147

Goitre, cause of, 84

Granules, appearance of, in glands, 110

of cerebellum, development of, 299, 303

Grey matter, formation of paths in, 356

Growth, a function of protoplasm, 24

a reaction to work, 47

Hæmatin, 68

Hæmatoidin, 68

Hæmochromogen, 68

Hæmoglobin, crystalline form, 66, 186

formula, 66

as oxygen carrier, 66, 186

spectrum, 68, 185

Hæmophilia, non-coagulability of blood, 76

Hallucinations, 362

Headache, a pain in the scalp, 106, 319

the brain’s warning of fatigue, 269

from strain of eye-muscles, 268

Hearing, analysis of compound vibrations, 405

capacity dependent upon education, 422

Hearing, Helmholtz’s theory of analysis of sounds, 419

range of sensations, 418

sense of, 404

upper limit, 418

Heart, anatomy, 217

automatism of, 238

development, 218

murmurs, 229

muscular tissue, minute structure, 261

nerves regulating beat, 237, 239

sounds of, 228

valves, their mechanism, 226

work done by, 219, 223

Heat, production of, by muscles, 254, 256

Heat-spots in skin, 429

Helmholtz’s theory of organ of Corti, 419

Hering’s theory of colour-vision, 388

Hormones, meaning of term, 89, 124

of pancreas and liver, 127

of stomach, 123

Humours in ancient medical theory, 79

Hunter, experiment of grafting cock’s spur in its comb, 47

Hydrochloric acid, part taken in digestion, 114

Hydrophobia, protective inoculation, 78

Hyperpnœa, excessive respiratory efforts, 182

Hypoblast, a layer of the embryo, 97

Illusions of movement, 335, 384

of size and distance, 400

Immunity, acquisition of, 20

Impulse of the heart, 225

rate of passage in muscle, 280

in nerve, 278, 280

theory of nerve conduction, 282

Inhibition, explanation of term, 311

of reflex actions, 311

Insects, efficiency of their muscles, 261

Instinct, due to brain-pattern, 359

Intelligence of animals, 359

Internal secretions, 83

Intestinal juice, digestive action, 119

Intestine, large, sacculation of its walls, 101

small, folds and glands of mucous membrane, 102

Intestines, movements of, 103

nerves of, 105

size and situation, 100

Iodine, importance of, to economy, 89

Iodothyrin, goitre due to deficiency of, 90

Iris, its function in regulating admission of light to eye, 394

Iron in food, 67

in hæmoglobin, 67

use of, in treatment of anæmia, 67

Irritability, a function of protoplasm, 10

Japanese, cultivation of sense of smell by, 370

Judgment of angles, 402

of distance and size, 401

of meaning of sensations, 396, 399

Kidney, ancestral history, 195

elimination of indigo by, 207

of birds and reptiles, 200, 207

hydrostatic mechanism, 189

minute anatomy, 196

Kinæsthetic sensations, absence from dreams, 363

part played by, in voluntary actions, 354

representation in cortex of brain, 350, 352

Knee-jerk, 274

Labyrinth of ear, 413

Lactate of ammonia, relation to urea, 13

Lacteals, lymphatic vessels of alimentary canal, 43, 131

Lactic acid produced in muscle, 46, 146

Larynx, closure during swallowing, 433

structure of, 430

Latent period of muscle after nervous impulse reaches it, 278

Laughter, respiratory mechanism of, 180

Lecithin produced by metabolism of nerve-tissue, 118

Leech, ganglion-cells of, 298

Leucocytes as protective agents, 52

death of, 54, 57

migration of, 49

number in lymph and in blood, 49, 61

origin of, 33, 51

source of fibrin-ferment, 74

Leucocythæmia, excess of leucocytes in the blood, 215

Levers to which muscles are attached, 286

Light, emission of, by animals, 291

Lime, influence upon coagulation of blood, 75

curdling of milk, 75

Lithates, or urates, constituents of calculi, 213

Liver, destruction of red blood-corpuscles in, 83

form and structure of, 160

former theories of its functions, 129, 163

manufactures urea and uric acid, 146, 162

of well fed sheep, 147

origin of, in vertebrate phylogeny, 34

Liver stores food, especially glycogen, 46, 145, 147, 161

Locomotor ataxy, 341

Ludwig’s view of mechanism of kidney, 200

Luminous glands, 291

Lung, exchange of gases in, 173, 184, 190

nerve-supply, 178

structure, 168

Lymph, amount of, in body, 37

composition, 49

relation to blood, 51

Lymph-spaces, 37, 43, 49

Lymphatic glands, structure of, 54

Lymphatic vessels, 43

Malapterurus, electric organs, 288

immense neurones of, 295

Manometer for measuring blood-pressure, description of, 238

Man’s ancestry, 153

Massage of abdominal viscera, 101

of muscles, 48

Meal, the story of a, 120

Meat, diet consisting solely of, 157

digestion of, 121

extracts of, as articles of diet, 159

Megacaryocytes, 65

Memory, physiological explanation, 356

Metabolism, chemical change in living tissue, 12, 273

Methæmoglobin, 69

Microscope, its discovery, 26

Migration of birds, 359

Milk, call for secretion of, by a hormone, 94

chemical and physical constitution, 132

digestion of, 127

Milk diet, reduction of bacteria in alimentary canal on, 138

Mind, physiology of, 354

Mosquitoes, production of sound by, 261

Motile cells, 32

Mountain sickness, 187

Mountains, highest climbed, 187

Mucous membrane, use of term, 97

Murmurs, in chest, in diseases of lungs, 169

of heart, 229

Muscle, change in appearance under microscope during contraction, 263

chemistry of contraction, 266

contraction a phenomenon of osmosis, 258

electric phenomena of, 278

means of promoting growth of, 271

measurement of its power, 285

nature of impulse which leads to contraction of, 282

Muscle of heart, its minute structure, 224

of insects, its efficiency, 261

plain, its minute structure, 258

plasma, its coagulation, 266

rhythm of voluntary contraction, 279

theory of its structure as a mechanism liberating energy, 234, 255

tone of, 272

tracings taken of contracting, 278

voluntary, its minute structure, 259

wastes when its nerve is severed, 274

work done by, proportional to load, 286

Muscles, arrangement in regard to the bones which they move, 286

co-operation in lifting a weight, 287

Muscular energy, source of, 235

Muscularis mucosæ of alimentary canal, 103

Musculi papillares of heart, 227

Music, chords admissible in, 408

Indian, division of octave, 408

primitive, prevalence of minor chords, 408

Musical tones and overtones, 406

Myelination of nerves, order of, 345

Myxœdema, dependent on disease of thyroid gland, 85

Myxomycetes, fusion of cell-bodies of, 27

Nasal chambers, air warmed in, 166

Negroes, their long heels, 285

Nerve, conduction in, theory of, 282

degeneration, 326

electrical phenomena, 279

indefatigable, 282

regeneration, 326

structure, 296

Nerves, depressor, 237

experiment of crossing, 327

fifth, 316

of heart, 239

of intestines, 426

protopathic and critical systems of, 425

secretory, of the salivary glands, 109

splanchnic, 236

superior laryngeal, 178

vagus, 104

vaso-motor, 239

Nerve-cells last throughout life, 148

limitations of their functions, 321

store of energy in, 320

transfer of impulses from cell to cell, 177, 300

their relation to muscle-fibres, 274

varying size of, 295, 322

Nerve-centres, 176

Nerve-force, improper use of expression, 281

Nerve-impulses, distribution in grey matter, 305

reinforcement of, 320

resistance to, at synapses, 306

Nerve-nets, pericellular, 301, 319

Nervous system, neuronic and extra-neuronic conduction, 310

phylogeny of, 332

Neuro-fibrillæ, 298

Neurone, origin of term, 293

transmission of current by, 328

various types of, 296, 323

Night-blindness, 378

Nissl’s bodies, source of nervous energy, 320

Nitric oxide, combination with hæmoglobin, 186

Nitrogenous equilibrium, 150

food, stimulating effect of, 157

waste, 210

Nœud vital of Flourens, 176

Normal diet, 151

Normal salt-solution, 82

Nucleo-proteins, source of uric acid, 215

Odours, classification of, 366

Œdema, or dropsy, 42

Olfactory membrane, structure, 366

Optic nerve, number of fibres, 378

Organ of Corti, structure, 415

theory of function, 417

Organs that have lost their prime functions, 87

Orientation, sense of, 335

Osmosis, 40, 128, 201

cause of muscular contraction, 235

Osteoblasts, bone-forming cells, 32

Osteoclasts, bone-eating cells, 65

Oxygen, amount required per diem, 166

carried by red blood-corpuscles, 66

Pain, influence of, upon action, 359

referred from viscera to surface of body, 316

relation to sensation, 313, 425

theory of, 312, 425

Pancreas, structure, 116

Pancreatic juice, constitution, 116

fat-splitting ferment of, 133

Papillæ of the tongue, various forms of, 97

Parathyroids, 86

Pepsin, digestive action, 115

Peptone prevents coagulation of blood, 77

Pericellular nerve-nets, 301

Perspiration, cools the surface of the body, 236

repressed during fever, 257

Peyer’s patches of lymph-follicles in intestine, 53

Phagocytes, germ-eating leucocytes, 60

consumption of red blood-corpuscles by, 82

Phosphenes, developed by pressure on eyeball, 383

Phosphorescence, cause of, 291

Phrenology, 343

Pictures, suggestion of solidity in, 401

Pineal body, phylogeny, 334

Pituitary body, 93

Plants, anæsthetized by ether, 12, 24

their metabolism, 15

their respiration, 24

Pleura, lining membrane of chest, 172

Pleurisy, pain of, 313

Pleuritic fluid, absorption of, 223

Pneumonia, changes in lung during, 169

Portal system of bloodvessels, 80

regulator of vascular tone, 236

Power of muscles, 285

Precipitins formed in blood, 19

Proteins, absorption by alimentary canal, 145

chemical constitution, 6

dietetic value, 157

fate after absorption, 212

Protopathic nerves, 425

Protoplasm, arrangement in cells, 30

constitution, 7

Huxley’s definition, 6

Pulse, cause of, 244

records of, 245

variations, 247

Purgatives, theory of action, 128

Purkinje-cells of cerebellum, 303, 340

shadows of retinal vessels, 375

Pus, origin of, from leucocytes, 57

Pyramids of cortex of great brain, 346

Rabbit’s ear, vaso-motor changes in, 235

Receptor, an organ specially sensitive to stimulation, 253

Referred pains from viscera, 316

Reflex action, inhibition of, 311

of scratching, 330

vinegar experiment with frog, 307

Regeneration of nerves, 326

Renal-portal circulation, 199

Renewal of tissues, 148

Rennin, ferment of milk, 16

Resistance in nervous system, laws of, 177, 307

Respiration, artificial, 179

effect on circulation, 221

a function of protoplasm, 23, 164

movements of, 171

nervous mechanism, 175, 179

in tissues, 165, 193

Respiratory centre in medulla oblongata, 176, 178, 182

Respiratory quotient, 174

Retina, structure, 374

Retinal pigment, relation to vision, 381

Rice ordeal, arrest of secretion of saliva, 112

Rigor mortis, 266

Rods and cones, respective functions in vision, 378

Rowing, value of, as exercise, 287

Saccharin, taste of, 367

Saline frog, respiration in, 193

Saliva, chemical constitution, 107

function of, 96, 107

Salivary glands, mechanism of secretion, 108

nerves of, 109, 236

Salts, absorption of, in alimentary canal, 128

Scientific method, definition of, 71

Scratch reflex, in dog, 330

Sea-sickness, 106

Secretin, hormone of pancreas and liver, 127

Secretion, accumulation of granules in cells, and their discharge, 110

a response to stimulation, 111

not a process of filtration, 110

Semicircular canals, their functions, 410

their positions in space, 335

Sensations, their apparent fusion, 356

many which escape attention, 318, 355

neutralization of one by another, 356

Sense-organs, origin in vertebrata, 336

Sensory areas in cortex of the great brain, 348

Sensory nerves, their connection with cerebro-spinal axis, 304

Shell-fish, poisonous extract of, 41

Shivering due to loss of heat from skin, 257

Sight. Cf. Vision

Skate, electric organs of, 289

Skilled movements, dependent upon kinæsthetic sensations, 357

Skin, experiment of cutting nerve, 424

variety of sensations from, 423

Sleep, condition of neurones in, 362

Sleeping sickness, 33

Smallpox, protection against, 78

Smell, disappearance of sense of, in later life, 370

dog’s dependence upon sense of, 366

reason for mental associations with sensations of, 371

sensitiveness to mercaptan, 365

Smells, nice and nasty, 369

Smoking, mental effect of, 371

Sneezing on looking at bright light, 317

Sore throat, cause of deafness, 412

Soul, Aristotle’s definition, 32

Sound, mode of conduction, 404

rapidity of vibrations of, 406, 418

Sounds of the heart, 228

periodic and aperiodic, 409

Spectacles, defects of eyeball which call for, 392

Speech, derangements of, due to disease of the brain, 353

mechanism of, 437

Sphygmographs for recording pulse, 245

Spinal dog, reflex action in, 330

frog, reflex action in, 307

ganglia, development of cells, 299

Splanchnic nerves, regulation of blood-pressure by, 236

Spleen, destruction of blood-corpuscles in, 80

structure, 79

Squint, correction of double vision in, 397

Starch, formula, 15

Star-shapes due to puckering of crystalline lens, 393

Starvation, statistics of, 156

Stiffness of muscles, cause of, 45, 271

Stimuli to muscles and nerves, 248

Stokes, discovery of spectrum of blood, 68

Stomach, digestion in, 120

glands of, 123

referred pains from, 316

shape and size, 99

Stone in the bladder, its cause, 213

Subconscious self, 355

Sugars, digestion of, 120, 136

formulæ, 15

Sun, apparent size near horizon, 399

Suprarenal capsules, their structure and function, 91

Sweetbread as article of diet, 215

Sympathetic system of nerves, 243, 325

diameter of fibres, 325

Synapses of nerve-cells, resistance interposed at, 306

Synaptases, constructive ferments, 18

Synthesis by plants, 15

Tapeworms, resist digestion in the intestines, 21

Taste, confusion with sense of smell, 364

localization on tongue, 367

sense of, in fishes, 365

sensitiveness to quinine, 369

Taste-bulbs, their structure, 368

Tattooing, removal of pigment by leucocytes, 55

Tea, its dietetic value, 122

Teeth, 96

Tendon, the growth of, from cells, 28

Tension of gases in the lungs, 190

Tetanus, the vibratile contraction of muscle, 279

Thoracic duct, discharges lymph into veins, 43, 131

Thorax, negative pressure in, 222

Thorns on dendrites of nerve-cells, 300

Thyroid body or gland, forms an internal secretion, 86

relation to goitre, 85

structure of, 85

Tight-lacing, deformation of organs which it causes, 220

Tigroids, in nerve-cells, stores of energy, 320

Tissues, respiration in, 165, 193

Tone of muscles, 272

Tongue, as organ of taste, 367

Tonsils, function as guardians of the fauces, 53

structure, 52

Torpedo, electric organs of, 290

Touch, sensations of, 426

Toxins produced by microbes, 20

Urea, amount relatively to proteins consumed, 155

antecedents of, 146, 212

chemical formula, 211

secreted during period of starvation, 156

Uric acid, amount secreted daily, 213

artificial production of, 13

chemical formula, 13, 214

diathesis, its relation to diet, 140

due to metabolism of leucocytes, 53, 216

form in which excreted, 207

made in the liver of birds, 13

Urticaria due to abnormal composition of lymph, 41

Vaccination, protective value of, 22

Valves of heart, their mechanism, 226

Vascular system, tone of, 236, 240

Vaso-constrictor nerves, 236

Vaso-dilator nerves, 236

Vegetables, dietetic value of, 139

digestion of, 125, 137

Vermiform appendix, 88

Villi of intestine, absorption of food by, 130

fat seen in, during active digestion, 134

Viscera, their insensitiveness to injury, 316, 426

Vision, colour contrasts, 382

duration of images, 382

judgment of distance and size, 411

solidity, 401

stereoscopic, doctrine of corresponding points, 397

Visual purple, 381

Vital action, definition of expression, 205

Vivisection, 4

Vocal cords, structure, 431

how modified in singing, 435

Voice, breaking of, in boys, 434

falsetto, how produced, 435

range of human, 435

registers, 436

Vomiting, 105

Vowels, synthesis by tuning-forks, 439

Wandering cells, 33

Warmth, appreciation of, by skin, 429

Waste substances, classification, 194

how eliminated from body, 59

Waterfall, negative after-image of, 384

Water-weed, experiment proving that it respires, 24

Wear and tear of bioplasm, 145

Wisdom-tooth, tending to disappear, 96

Yawning, beneficial effect on circulation, 222

nervous mechanism of, 180

Young’s theory of colour-vision, 385

Zymogen, 110

THE END

BILLING AND SONS, LTD., PRINTERS, GUILDFORD

FOOTNOTES: