474 



STANLEY C. BALL 



chromatin reticulum, or that fewer black masses are present 

 than in the oocytes which are slightly younger. It seems prob- 

 able then that the oocyte nuclei eliminate a part of their chroma- 

 tin in the form of spherical fragments which come to lie in the 

 cytoplasm. 



Of considerable interest in relation to the nourishment of 

 the embryo is a body always found present in the oocyte after 

 it has commenced its growth. This is the 'Dotterkern' or 

 'yolk-nucleus.' A light brown color in iron-haematoxylin-eosin 



. chr. 



chr. rn. -kvvv'-®^"?' 



Text fig. 3 Portion of a frontal section of the ovary to show masses of chro- 

 matin before and after ejection from the nucleus, chr.m., chromatin mass; 

 ej.chr., ejected chromatin; niic, nucleus; nucl., nucleolus; mit., mitochondrial 

 mass. X 1016. 



preparations brings the yolk-nucleus into contrast with the 

 cytoplasm in which it is imbedded (figs. 4, 6, 7). At a magnifi- 

 cation of two hundred fifty its appearance is that of a homogene- 

 ous gelatinous mass, sometimes existing as a single compact 

 body, but often as flocculent material in one or more smaller 

 masses of different sizes. The substance consists ultimately 

 (fig. 7) of a multitude of granules which are so extremely fine 

 and so closely grouped that a high magnification is necessary 

 in order to distinguish them as such. 



