Sudan III in Metabolism and Inheritance 1 79 



in the re-distribution of the stain and fat in the cells which arise 

 by division of the egg, are not different. Here we must beheve 

 that each cell of a dividing pair will carry stain in very close propor- 

 tion as it carries fat. This is the testimony obtained from all so- 

 matic tissues and the writer has shown that the general conditions 

 of this statement are fulfilled in the oocyte and egg itself, since 

 the germinal disc and the latebra of these stages take least stain 

 (intra vitam) and are know^n to contain least fat. When in the 

 course of development there arises a variety of body regions, some 

 of which are less favorable for oxidations and therefore more 

 favorable forthe storage of fats, the stain-containing fats may 

 become transferred to these regions of the embryo, precisely as 

 occurs in the somatic tissues of the adult. Localized areas of 

 stained fat thus arise during embryonic life. 



If now one compares and contrasts these processes with those 

 known to accompany inheritance, i. e., developmental processes, 

 some interesting features appear. There is, to be sure, transmis- 

 sion of the dye from soma to germ, there is 3. persistence o{ that 

 which is transmitted to such an extent as to cause this soma 

 obviously to display the "new character." If in the chick the 

 body fat were used up in egg production, ^as was elsewhere noted 

 to occur in the salmon, some of the dye would of necessity again 

 be deposited in the several eggs next formed; these eggs would in 

 turn sjpply the somatic tissues developing from them. But this 

 must inevitably come to an end in a fezo generations, the stam, 

 sooner or later, having become diluted to the vanishing point. 

 Again, there is absolutely no new growth of the material forming this 

 "character," nor is there any chemical change either in early or m 

 late phases of the life cycle. Morphological change does however, 

 accompany each change in the disposition of fat within the organ- 

 ism, the color-picture thus being a moving one, different in each 

 succeeding stage of development. 



These striking contrasts with what we recognize as the basic 

 things in developmental phenomena may well cause many to 

 inquire: Why do we stop at all to consider the phenomena under 



' I have observed a hen to lay four eggs after the beginning of a "starvation" experiment; the 

 last of those eggs was laid on the twelvth day of starvation and much of the fat of its yolk was 

 undoubtedly derived from the body fat of the bird. 



