938 



INDEX. 



Vitreous humor, 849 



Vocal cords, 757 



muscles of, 762 



Voice, 757 



production of, 758 



Vomiting, centre for, 817 

 mechanism of, 330 

 nervous mechanism of, 334 



Walking backward in the horse, 754 

 mechanism of, in the horse, 744 

 in man, 737 



Water, 124, 191 

 in cells, 86 



White blood-corpuscles, 479 



Wool-producing animals, food required by, 



688 

 Worms, digestive apparatus of, 205 



Xanthin, 663 



Xantho-proteic reaction of proteids, 91 



Yawning, 604 



Yelk of egg, structure of, 20 



Yellow spot of the retina, 865 



Zona pellucida, 15 



radiata, 15 

 Zymogen, 409 



