146 Transactions of the Society, 



youngest ascidian oocytes Hirschler describes the presence of two 

 granular bodies —one fuchsinophile, which is the chondriome (i.e. 

 the representative of the mitochondria of the cell) ; the other stained 

 black by osmium tetroxide, and forming the primordium of the 

 Golgi apparatus of the egg. From the former, which Hirschler 

 calls the chondriome, develop both yolk nucleus and definitive 

 mitochondria. AVith regard to Hirschler's use of the term " chon- 

 driome," the word here means the entire content of mitochondrial 

 substance in the cell, whether a single grain, or many grains 

 collectively, and this meaning is the one in which most French 

 observers have used the word. 



Hirschler says, " One can suppose that the small red (fuchsino- 

 phile) yolk nuclei of the young oocytes, even alone on account of 

 their specific staining affinities, represent the chondriome of these 

 cells, and that during the cell growth, out of this chondriome, 

 which consists of small mitochondrial bodies, are produced on the 

 one hand small granular mitochondria, and on the other hand the 

 peculiar substance of the yolk nucleus. In this view, the yolk 

 nuclei would be regarded as derivatives of the chondriome, and 

 such an interpretation would then harmonize with the accounts 

 given in the literature. But by simply looking at the facts alone, 

 it seems that the mitochondria and the yolk nuclei have a common 

 origin, and develop out of fuchsinophile spherical bodies, which 

 represent at the same time mitochondria and the youngest stages 

 of the yolk nuclei." 



Following out the history of the yolk nucleus of ascidian eggs, 

 Hirschler remarks, " As long as the yolk nuclei exhibit a red or 

 reddish staining (fuchsin) they appear for the most part as com- 

 pact spherules which are directly applied to the nuclear membrane. 

 Later, however, the mitochondrial substance is given off from 

 them, and they change their form and structure quite considerably 

 in older oocytes." 



A kind of capsule becomes formed around the periphery of the 

 growing yolk nucleus, while the interior of the latter gradually 

 comes to stain in the same way as the ground cytoplasm. Hirschler 

 continues, '* But before the yolk nuclei have received their capsular 

 form, quite peculiar stalks develop out of their substance, by which 

 they are attached to the nuclear membrane. Usually a yolk 

 nucleus possesses only one stalk, but some have two or even 

 three." These stalks are intimately related to the nuclear mem- 

 brane and thence to the chromatinic reticulum. Hirschler says 

 with reference to the latter fact, " One could suppose that through 

 these stalks certain nuclear substances are led in a fluid state 

 through the nuclear membrane into the yolk nucleus and promote 

 the growth of the latter." In support of this view Hirschler states 

 that he finds granules, possibly chromatin, lying in the substance 

 of the yolk nucleus. 



