INDEX 



901 



WOLFFIAN BODIES. 



Wolffian bodies, 872 et seq. 



duct, 872 



ridge, 835 

 Wooldridge's method of preparing tissue-fibrino 



gen, 402 



Word-centres, 762 

 Worms, circulatory system in, 229 

 Wright, Hamilton, sleep theory, 699 , 



X. 



Xanthine, 332, 33?, 403, 562 

 presence in the spleen, 332 

 Xantho-proteic reaction, 397 



Yawning, mechanism of, 365 

 Yellow elastic fibre, 43 



fibro-cartilage, 52 



spot of Sommering, 771, 793 

 Yolk-sac, 835, 849, 839 et seq. 

 Yolk-spherules, 825 

 Young-Helmholtz theory, 800, 801 



Zona pellucida, 20, 824, 830 

 Zonule of Zinn, 776 

 Zuntz, output of the heart, 246 

 Zymogen, 475, 482 



