Mitoclwndria, Golgi Aijparatus, and Yolk. 145 



parted company with the Golgi rodlets or dictyosomes ? We are 

 inclined to believe that the original archoplasm may have become 

 loaded with lipins and fats and thus metamorphose into yolk 

 elements. 



Basophility and Oxyphility of the Ground Cytoplasm 

 DURING Oogenesis. 



Pari passu with the evolution of the mitochondria and Golgi 

 apparatus of the growing oocyte, there may occur changes in the 

 chromophility of the egg cytoplasm ; probably there is some 

 definite relationship between the ground cytoplasm and of the 

 degree of spreading out and development of the protoplasmic 

 inclusions. More possibly, however, the relation is between the 

 nucleus itself and the surrounding cytoplasm. Hirschler has 

 noted important changes in the chromophility of the egg cytoplasm 

 during the growth of the ascidian oocyte. In different growth 

 stages the ground plasma shows a very variable staining, from 

 which it may be concluded that during growth of the ovum it 

 undergoes far-reaching metabolic changes. 



Hirschler distinguishes three chief conditions of staining: — 

 <1) primary oxyphilia, (2) basophilia, and (3) secondary oxyphilia. 

 He believes that the Golgi apparatus may in some way be con- 

 cerned with the passage of the chromophility of the cytoplasm 

 from oxyphile to basophile, and considers that the nucleus is not 

 directly concerned with the process. 



The exact significance of changes in chromophility of the Qgg 

 cytoplasm are unknown to us, but may indicate something of the 

 growth metabolism of proteid substances. 



Yolk Nuclei. 



Wilson {JfJf) says, " During the growth period (of an egg) a 

 peculiar body known as the yolk nucleus appears in the cytoplasm 

 of many ova, and this is probably concerned in some manner with 

 the growth of the cytoplasm and the formation of the yolk. Both 

 its origin and its physiological role are, however, still involved in 

 doubt." 



Many authors have loosely used the word '' yolk nucleus " to 

 mean any largish granule which they have noticed in the egg 

 cytoplasm. The archoplasm and mitochondria have both been 

 erroneously identified as " yolk nuclei." That there may be such 

 a body as a true yolk nucleus, distinct from any other known 

 cytoplasmic inclusion, cannot be doubted. 



Hirschler (^^) finds a true yolk nucleus which stains like the 

 mitochondria during the early stages of its development. In the 



l 



