2O8 C. M. CHILD. 



extremely improbable. In no case has a whole testis been found 

 undergoing degeneration, yet in all the testes most of the divi- 

 sions before spermatogenesis proper were amitotic and in the 

 great majority the first divisions certainly were amitotic. As was 

 suggested in the preceding section degeneration of cell-groups in 

 post-spireme stages may be connected with the fragmentation of 

 spermatocyte nuclei though this seems improbable, and more- 

 over, it does not explain degeneration in pre-spireme stages. I 

 believe, though I see no way of demonstrating it, that the method 

 of origin of the cell-groups in the testis has no connection with 

 their degeneration. 



The degenerating cell-groups vary greatly in appearance 

 according to the stage at which degeneration begins and the dif- 

 ferent stages of degeneration itself. In many cases, though not 

 always, it is possible to determine from the appearance of the 

 degenerating mass approximately the stage at which degenera- 

 tion began. In some cases cells in the same stage of develop- 

 ment undergo two different processes of degeneration. 



Some of the characteristic forms and stages of degenerating 

 cell groups are shown in the following figures : in these figures 

 no attempt has been made to represent the cytoplasmic back- 

 ground. This varies somewhat in density and staining in differ- 

 ent cases. Vacuoles and spaces are indicated by broken lines. 

 The method of reproduction exaggerates the depth of shade in 

 the more deeply staining portions. Fig. 5 I (PI. XV.) shows a 

 small group of cells from a young testis in the first stages of 

 degeneration. The first evidence of degeneration in these cases 

 is a condensation of the cytoplasm and a massing together of the 

 nuclei, and the degenerating group becomes quite distinct from 

 other cells, usually lying in a space. Fig. 52 (PI. XV.) shows a 

 later stage of this form of degeneration ; the nucleoli increase in 

 size and stain very deeply, the nuclear membrane becomes indis- 

 tinct, and the whole mass stains more intensely. Later, as shown 

 in Fig. 53 (PI. XV.), the mass breaks up into irregular deeply 

 staining fragments and strands which are distributed through the 

 testis and are often found in the cytoplasm of other cells sur- 

 rounded by small vacuoles ; a few of these fragments in the cyto- 

 plasm are shown in the figure. 



