698 
Rhythn, law of, 206, 
in nature, 36. 
appetite, 362. 
respiratory, 379, 
Retina, affections of, 578. 
Retinal stimulation, laws of, 580. 
Rigor mortis, 192. 
Rheoscopic frog, 191. 
Rouleaux of blood-cells, 158. 
Saliva, 306. 
amylolytic action of, 306. 
of parotid gland, 307. 
comparative, 308. 
pathological, 308. 
Salivary glands, physiology of secretion 
of, 319. 
Salts of milk, 292. 
Sarcolemma, 170. 
Secretion, physiology of, 319. 
nature of the act of, 326. 
of urine, 426, 
Segmentation of ovum, 65. 
Segregation, 130. 
Self-digestion of digestive organs, 329, 
Semicircular canals, co-ordinating func- 
tions of, 502. 
Sensations, visual, 576. 
Senses, general remarks, 548. 
Sensory area, 525. 
Serum, composition of, 155. 
Sexes at different periods, 667. 
Sexual selection, 42. 
Sighing, 407. 
Skatol, 686. 
Skin, functions of, 412. 
protective functions of, comparative, 
413. 
respiration by, comparative, 415. 
absorption by, 418. 
as an organ of sense, 451. 
Sleep, 526. 
Smell, sense of, 620. 
Sneezing, 407. 
Sobbing, 406. 
Solidity in vision, 595. 
Somatopleure, 74, | 
Somnambulism, 529. 
Sound, cardiac, Marey’s, 234, 
Sounds, cardiac, 235. 
respiratory, 381. 
Special considerations as to food, 358, 
ANIMAL PHYSIOLOGY. 
Special considerations as to digestion, 468. 
vision, 597, 
hearing, 616. 
voice and speech, 652. 
Spectrum of hemoglobin, 386. 
Spermatozoén, 52. 
origin of, 61. 
Speech, 649. 
consonants, 650. 
Spherical aberration, 572. 
Sphygmograph, the, 247. 
Spinal nerves, 626. 
cord, 480. 
reflex functions of, 484, 
as a conductor of impulses, 487. 
automatic functions of, 493. 
comparative, 495, 
evolution, 496. 
Splanchnopleure, 74. 
Sporangia, 15. 
Spleen, metabolism of, 436. 
nervous system’s influence on, 489. 
pulp, comparative, 437. 
Stasis, 281. 
Starvation, influence on metabolism, 450. 
Steapsin, 316. 
Stimulation, laws of retinal, 581, 
Stimulus, 170. 
maximal, 185. 
minimal, 185. 
sub-maximal, 185, 
Stomach of ruminants, 300. 
physiology of secretion by, 323. 
comparative, 330, 
movements of, 335. 
Subjective phenomena, 591, 
Succus entericus, 317. 
Summary of physiology of blood, 165. 
muscle and nerve, 208. 
circulation, 286. 
digestion, 355-364. 
respiration, 410. 
functions of the skin, 418. 
urine, 430. 
reproduction, 89. 
voice and speech, 652, 
spinal cord, 497. 
functions of the brain, 548. 
of evidences of evolution, 47. 
Swallowing, comparative, 334, 385. 
Sweating, 415. 
physiology of, 417. 
