584 



PROTOPLASM 



Z 



Xanthophyll, 516 

 Xerophthalmia, 514 

 X rays, 392, 402 



effect on heredity, 410 

 on protoplasm, 408-409 



therapeutic value of, 408 



Yeast, pH of, 330 



Zimmerman, 521 

 Zinc, 435 

 Zirkle, C, 274 

 Zirkle, R. E., 410 

 Zocher, 263 



Zsigmondy, classification of colloids, 

 117 



gold number, 147 



size of gold particle, 89 



ultramicroscope, 97 

 Zwitterion, 486 



i 



i 



I 



