472 



IXDEX. 



PAGE 



Schlemm, canal of, 53 



Schneideriau mucous membrane, . 25 



Sclerotic, 45 



development of, 402 



Scrotum, . 314 



Sebaceous follicles, first appear- 

 ance of, 397 



Secondary membrana tympani, 



156, 165 



Semen, 323 



in advanced age, 329 



ejaculation of, 335 



Semicircular canals, 165, 214 



functions of, 224 



development of, 403 



Seminal vesicles, 320, 327 



Seminiferous tubes, 316 



structure of, before puberty, 327 



Septum lucidum, development of,. 401 

 Septum transversum of the semi- 

 circular canals, 219 



Serotina, 383 



Sex of offspring, determination of, 345 



Sexual generation, 258 



Sexual intercourse, normal fre- 

 quency of, 333 



Sexual orgasm, in the male, 335 



in the female, 336, 340 



Sight (see vision), 37 



Sinus terminalis of the area vascu- 



losa, 430 



Siren, mechanism of, 174 



Skeleton, development of, 393 



ossification of, 396 



Skin, first appearance of, 397 



Skull, development and ossifica- 

 tion of, 395 



Smell (see olfaction), 25 



Sommerring, yellow spot of, 55 



Sound, physics of, 166 



laws of vibrations of, 169 



vibrations of, in vacuo, 169 



intensity of, 170 



reflection and refraction of, . 171 



as distinguished from noise,. 171 



pitch of, 173 



range of vibrations of, in mu- 

 sic, 174 



quality of, 179 



harmonics, or overtones,.. . . 182 



two sounds producing silence, 190 



Special senses, general characters 



of, 12 



Spermatic cord, 314 



Spermatozoids, 325 



Spermatozoids, intermediate seg- 

 ment of, 326 



influence of reagents, cold, 



etc., upon the movements of, ... 326 



development of, 328 



mechanism of the penetration 



of, into the uterus, 337 



course of, through the female 



generative passages, 341 



passage of, through the vitel- 



line membrane, 352 



passage of, through a delicate, 



animal membrane, 353 



number of, necessary for fe- 

 cundation, 353 



Spherical aberration, 80 



partial correction of, by the 



iris, 81 



correction of, in compound 



lenses, 82 



Spina bifida, 395 



Spinal cord, development of, 398 



central canal of, 398 



Spiral canal of the cochlea,. . 165, 215 



Spleen, first appearance of, 409 



Spontaneous generation, so called, 258 



Stapedius muscle, 159 



Stapes, 157 



development of, 412, 413 



Stercorine, 455 



Stereoscope, 125 



Stomach, development of, 406 



Strings, subdivisions of, in vibra- 

 tion, 183 



Styloid ligament, development of, 



412, 413 

 Subclavian arteries, development 



of, 432 



Subclavian veins, development 



of, 435 



Sudoriparous glands, development 



of, 397 



Summation tones, 187 



Superfecundation, 347 



Superfoatation, 347 



Superior maxilla, development of, 



412, 413 

 Suprarenal capsules, development 



of, 424 



Sympexions, 324 



Tarsal cartilages, 139 



Taste (see gustation), 232 



Taste-buds, or taste-beakers, 251 



Taste-cells, 252 



