INDEX 



455 



Senescence, 429 



Setae, locomotor, 128 



Sex determination, 228-236 

 s-element in, 232 



Sexual organs, atrophic changes 

 in, 435 



Shattuck and Ballance on car- 

 cinoma, 423 



Sheep-scab, 337 



Sheep-tick, 329 



Side-chain theory of Ehrlich, 366 



Sight, development of, 162 



Sitotropism, 48 



Situs inversus viscerum, 227 



Size of organisms, relation to 

 complexity, 113 



Skin, atrophic changes in, 435 



Skin-grafting, 413, 415 



Small-pox and vaccination, 377 



Smell, development of, 166 



Smut of corn, 321 



Somatic cells, 191 



differentiation of, from ger- 

 minal cells, 119 

 death, 438 



Spallanzani, 25, 202, 393, 394 



Special sense, organs of, 159 



Specialization of cells, 110 



Species, 297 



Spencer, Herbert, and evolution, 



276 

 on heredity, 238 



Spermatocytes, secondary, 193 



Spermatogenesis, 192 



Spermatozoa, 192 



Spermatozoon, locomotion of, 80 



Spillman on Mendel's law, 259 



Spina bifida, development of, 227 



Spirem, 104 



Spirillosis, 336 



Spirochaeta duttoni, 336 



Spirochsetes, 348 



Spirogyra, 115 



conjugation in, 179, 180 

 Spleen, regeneration of, 402 

 Sponges, reproduction in, 185 



structure of, 120 

 Spongioplasm, 95 

 Spontaneous generation, 21 

 Sporosacs, 184 

 Sporozoa, parasitism of, 324 

 Sporulation in coccidium, 170 

 St. Augustine, 271 

 Starch, formation of, 89 

 Stentor, nucleus of, 99 



regeneration in, 389 

 Stigma, 187 

 Stimulation, chemical, 46 



electric, 60 



food, 48 



gravity, 63 



light, 54 



mechanical, 43 



oxygen, 52 



photic, 54 



thermal, 37 



water, 50 



Stimuli, action of, 34 

 Stirp, 243 

 Stomoxys, 330, 347 

 Strasburger, 178 



on grafting, 427 

 Strepsiptera, 332 

 Strobila, 342 



Structural relationship, 289 

 Sundew, 43. See Drosera. 

 Sun's rays, effect of, 54 

 Surra, 330 

 Suspensorium, 181 

 Swammerdam, 202 

 Symbiont, 314 

 Symbiosis, 314 



blood-relationship and, 312 

 Sympathetic system, 157 



