292 H. M. KINGERY 



Altmann's or similar methods, granules are found. While I 

 have not made a special study of this point, my results seem to 

 bear out the conclusions of Schaxel; however, although mito- 

 chondria of one type or the other may predominate in preparations 

 made by one or the other of these methods, both granules and 

 rods or threads are found in both kinds of preparations. Lewis 

 and Lewis think it quite probable that the mitochondria, 'malle- 

 able' or plastic as they appear to be, may have their shape 

 affected by different methods of treatment. 



Moreover, it is possible that the mitochondria represent the 

 structural expression of the reducing substances concerned in 

 cellular respiration (Kingsbury, '12). As Le\vis and Lewis 

 suggest, it is possible that they are continually being formed and 

 as continually destroyed (oxidized) in the cytoplasm in the course 

 of the metabolic activity of the cell. It is evident that a pro- 

 nounced change in the metabolism of the egg-cell is correlated 

 with its marked growth in size, from a small cell in the germinal 

 epithelium to a mature ovara. Furthermore, the part played 

 by the follicle cells in the growth of the oocyte must also affect 

 the metabolic activity of those cells. It would seem reasonable, 

 then, to conclude that it is only natural that the mitochondria 

 should not be constant in shape in any one particular kind of 

 cell, but should vary in different cells, or even in the same cell 

 at different times. 



In returning now to the question of the post partum prolifera- 

 tion of germ cells, the present discussion will take up only the 

 work of von Winiwarter and Sainmont on the cat in connection 

 with my results in the mouse. From the little these authors 

 have said about this new^ formation of egg-cells, the process is 

 limited to a brief period of time shortly before sexual maturity 

 (three and one-half to four months). As a result of a multiplica- 

 tion of cells in the germinal epithelium, masses or strands of 

 cells grow down into the tunica albuginea, retaining a connection 

 with the epithelium. In these strands, certain of the cells 

 appear with their nuclei in the 'deutobroque' stage. The germ 

 cells of embryonic origin have largely degenerated by this time, 

 so there is room in the ovary for these new egg-cells which, to- 



