INDEX. 



457 



Visual sensations, discrete, conditions of, 



iv. 79 



,, ,, iu relation to visual percep- 

 tions, iv. 123133 

 ,, ,, simultaneous, iv. 123 

 ,, substances, hypothetical, iv.118, 119 

 ,, units, retinal, iv. 81 

 Vitellin, a constituent of yolk, iv. 353 

 Vitreous humour, the, iv. 29, 170 

 Vocal cords, structure, iv. 313 



,, ,, voice produced by vibration 



of the, iv. 306, 315 

 ,, ,, tightening and slackening of 



the, iv. 322 



Voice, the, iv. 306332 

 ,, how produced, iv. 306 

 ,, fundamental features of the, iv. 316 

 ,, different qualities of, iv. 326 

 chest and head voices, iv. 329 

 ,, registers of the, iv. 331 

 breaking of the, iv. 332 

 Volkmann, his hsemarlromometer, 220 

 Voluntary movements, their tetanic cha- 

 racter, 140 



,, ,, nervous mechanisms for, 



914, 1034, 1056, 1066 

 Vomiting, mechanism of, 460 

 Vowel chamber, iv. 333 

 Vowels, how formed, iv. 334 



Walking, how effected, iv. 343 



Walls, vascular, their influence on tran- 



sr.dation, 504, 506 



Warmth, its effect on skin action, 675 

 W ei.ste matters, their discharge from the 

 living body, 2 



,, ,, given out by amoebae, 4 



,, not necessarily useless, 43 



,, elimination of, 632 



,, nitrogenous, 102 



,, ,, not increased by muscle 



contraction, 103, 106, 

 805 

 Water, secretion of, by the glands, 416 



,, varying amount of, in living tissue, 

 507 



its absorption into the portal sys- 

 tem, 513 



,, intestinal secretion of, 522 



,, its discharge by the kidney, 674 



,, by the skin, 699 

 Waves of contraction, muscular, 86 



,, pulse, dicrotic, their nature, 266 



,, ,, predicrotic, 270 



., ,, anacrotic, 271 



,, of sound, iv. 180, 224 



of light, iv. 84 



Waves of nervous and muscle impulse,125 



Wax of the ear, secretion of, 693 



Web of frog, arterial changes visible in, 



306 



Weber's law, iv. 73, 226, 275 

 Weight, human, curve of, iv. 404 

 Wharton's jelly, iv."377 

 Whispering, how effected, iv. 336, 341 

 W T hite, sensation of, produced from mix- 

 ing of colour sensations, iv. 90 

 Willis, circle of, 1131, 1134 

 Winking, how effected, iv. 172 

 ,, chief use of, iv. 175 

 Wolffian bodies, the origin of the con- 

 ducting part of the testis, iv. 364 

 "Word -deafness," 1089 

 Work, mechanical, in living body, 2 

 ,, done by a muscle-nerve prepara- 

 tion, 136 et supra 

 ,, amount done by heart, 253 

 ,, daily, estimate of, 803 

 ,, mechanical source of energy of, 



805 



,, production of heat increased by, 

 813 



Xanthin, a constituent of urine, 650, 758 

 present in the thyroid, 762 

 ,, ,, ,, thymus, 768 



Xanthoproteic test for protein, 17, 18 



Yawning, 630 

 Yellow elastic fibres, 190 

 ,, spot, structure, iv. 66 

 ,, ,, colour sensations as affected 



by, iv. 106 



Yolk, chemical composition of, iv. 356 

 Young-Helmholtz, theory of primary 

 colour sensa- 

 tions, iv. 91 



,, ,, ,, as applied to 



colour blind- 

 ness, iv. 101, 

 104 



,, ,, , of simultane- 



ous and suc- 

 sive contrasts, 

 iv. 129 



Zinn, zonule of, iv. 30 



,, passage of fluid by the, iv. 171 

 Zona pellucida or radiata, iv. 355 



,, spongiosa of cord, 865 

 Zone, ciliary, iv. 26 



,, peripheral of capillaries, 335 



Lissauer's, 875 

 Zymogens, 415, 419 



