674 JOHN BEARD, 



(Fig. 40) shows a germ-cell, differiog only in size from a normal one. 

 [f this be normal, it is the smallest yet seen in any embryo of 32 mm 

 or under. But, according to Flemming, one of the earliest signs of 

 this degeneration is reduction in size. The next one is depicted in 

 figures of two sections of the same cell (Figs. 38 and 39). It reveals 

 a more advanced stage of atrophy. Yolk-plates are still present. The 

 nucleus is in chromatolysis. Its contents are broken up into two well 

 marked portions, each lying in a vacuole; and there are other and 

 minuter portions in other parts of the cell. Vacuolation of the cyto- 

 plasm is initiated. Fig. 41 shows a similar, but more pronounced, 

 condition in another instance. The yolk is slighter in amount. There 

 is a large vacuole. The nuclear contents are pressed somewhat to 

 the side of the cell. They stain deeply, and, most important of all, 

 exhibit the twin-grouping. The next figure (Fig. 44) presents extreme 

 vacuolation of the cytoplasm. The nuclear contents are pressed to 

 the side, no duplication of them was determined. 



Fig. 45, perhaps, also belongs to this type, but it differs from 

 the preceding instances in a peculiarity, which seemingly is associated 

 with the second. The two halves of the degenerating cell are unequal 

 in size, there is duplication of the npclear contents, and these lie in 

 part in a couple of vacuoles. Whether the black particles were yolk, 

 or simply blackened fat, could not be clearly made out even with the 

 2 mm apochromatic objective and ocular 18. In the other instances 

 described the blackened particles were clearly seen to be yolk-plates 

 under this magnification (2250 diameters). 



The second type appears to me to be associated with pluripolar 

 mitoses, which, however — possibly because of the obscurity caused 

 by the yolk — I have not been so fortunate as to see ^). Only three 

 examples of it have been given (Figs. 43, 47 and 48), and these are 

 very simple ones. Nothing is more certain than that more complicated 

 ones could have been depicted, had it been possible to work out the 

 details. 



1) Compare Rückert ('87, p. 162 — 163), who arrived at a like 

 conclusion concerning his "megaspheres" without being able to see the 

 mitotic figures. Ziegler ('96, p. 367), on the other hand, states that 

 they become multinuclear by amitosis. With Prof. His (Lecithoblast 

 und Angioblast etc., in: Abh. Sachs. Ges. Wiss , V. 26, p. 173 — 328, 

 1900) the writer believes, that most if not all of the cases of so-called 

 amitosis are due to pluripolar divisions, or attempts at such. But in 

 opposition to the former it must be maintained, that such pluripolar 

 mitoses are evidence of, and invariably result in, degeneration. 



