Contributions to the Study of the Oogeneds of Patella. '• 



in osniic acid. Such granules are shown in the young 0()cytes at 

 CH. in Plate 1, tig. 1, and in Plate II, figs. 13 and 14. ^ Wlule tlie 

 oocyte grows and increases in bulk, these granules become dispersed 

 in the protoplasm. During the early stages of oogenesis they seem 

 to remain almost inert while the Golgi apparatus is actively 

 dividing and spreading out, so influencing the formation of yolk 

 spheres throughout the cell. In fig. '.), which shows the yolk bodies 

 scattered on all sides of the nucleus, the chondriome is represented 

 by a few small granules in process of division. The same thing is 

 shown again in fig. 15, which represents a somewhat later stage, 

 drawn under a lower magnification. The yolk Ijodies here shown 

 as colourless spheres, owing to the fat having been abstracted by 

 the turpentine, are seen widely distributed, but the mitochondria 

 are represented by a few slowly dividing granules. The same 

 process is seen again in fig. !>, which shows the various stages in 

 the formation of yolk granules ; the Golgi elements are well 

 advanced in their activities, while the chondriome consists of a few 

 small groups as before. 



Xot until the yolk bodies are well distributed in the oocyte do 

 the mitochondria commence active division. Fig. 16 represents 

 an oocyte at this stage. The yolk bodies are seen occupying the 

 greater part of the cell, and in the cytoplasm amongst them are 

 the groups of actively dividing mitochondria, shown in black. At 

 fig. 17 one of these groups is drawn under a high magnification. 

 It shows some suiall granules in process of fission, otliers liaving 

 grown larger, spreading out from the centre of distribution and 

 continuing to divide as they do so. Eventually they become 

 scattered fairly regularly amongst the yolk spheres in all parts of 

 the 0("»cyte, as is shown in fig. 11 at M. 



It would seem that durint; their growth the mitochondria 

 became somewhat swollen with reserve food products intended to 

 supply energy, after fertilization, for the development of the embryo. 



That the mitochondria take no direct part in the formation of 

 yolk I conclude from the following observations. Yolk Ijodies are 

 formed directly under the influence of the Golgi rods. There is no 

 fusion of ( lolgi elements with mitochondria, but the latter remain 

 separate throughout oogenesis. They do not become active in the 

 cell until the process of yolk formation is well advanced, and there 

 is no evidence »if mitochondria becoming swollen to form yolk 

 bodies, the latter bodies staining differently and always being 

 considerably larger than the biggest mitochondria. 



Discussion. 



In considerino' the role of ( jrolgi appai-atus and mitochondria in 

 0(')geuesis it is of interest to bear in mind what so far has been 

 <liscovered concerning their behaviour in the cell. Although there 



