no 



' >S< \K 



of a sample. 1.605 grams of such yolk were rolltvtrd from a 

 single one of the new yolk spaces; this was not all, but nearly all 

 of the contents of the cavity. In order to slum how closely 

 its chemical composition agrees with that of other tOnn< of true 

 yolk, I have added to the table the numbers resulting from the 

 analysis of four such samples of yolk. Reference to the table 

 readily shows the essential similarity of all these substances ; and 

 likewise a point or two of notable difference. 



In Per. Cent, of Solids. 



It is true that I have selected for this comparison analyses 

 which most closely agree with the analysis of the "cxtra-fol- 

 licular" yolk. The high water content of the latter is of no con- 

 sequence; an analysis of "white" yolk from the hen having 

 yielded more than 80. per cent, of this constituent . 



The high ash content, and very low protein content, do indi- 

 cate however a species of yolk not in all respects like that pro- 

 duced by the follicular cell and the ovum. In these two respects 

 this yolk stands as a rather bold extreme in a long series of 

 analyses of normal yolk. It can be said therefore that though 

 this substance is certainly "yolk," its peculiar origin stamps its 

 chemical composition with a specificity of its own. 



The foregoing recital of the facts is perhaps hardly sufficient 

 to uncover at once to every reader one of the points of interest 

 in these findings; at any rate it is a point of interest to the writer. 

 I refer to the fact that in all of the hitherto known cases of 

 yolk formation the whole process of yolk building and stoi gi 

 appears so glaringly and profoundly ideological. The ovum pre- 

 pares and stores food for an embryo that is yet to form; a 

 follicular cell passes on this rich material only to an ovum \\liich 

 in turn accumulates for a promised organism that will arise and 



