1916.] NATURAL SCIENCES OF PHILADELPHIA. 17 



cell. In fig. 10 the nucleus projects out from the sides of the cell, 

 while the cytoplasm is reduced and shows uneven contours. In 

 fig. 11 there is seen both nuclear enlargement and cytoplasmic 

 reduction. 



The initial steps in the evolution of the male element are illustrated 

 by the figures just described. The details of this evolution vary 

 greatly, and it is doubtless true that this variation in detail is the 

 result not only of variations in the actual biological process itself, 

 but is also dependent on the technique. Thus, in iron hsematoxylin 

 preparations there are always associated with the nucleus one or more 

 intensely black granules which are either not visible at all or only 

 faintly visible in Delaficld or thionin preparations. Furthermore, 

 in material stained in thionin the cytoplasm is frequently seen to be 

 separated into two portions, as shown in Plate I, figs. 12, 13, and 14. 

 Here the cytoplasm is broken up into a number of lumps or streaks 

 either lying embedded in a faintly staining ground substance (figs. 12 

 and 14) or apparently lying free in the vacuole which the parasite always 

 produces in the mouse cell (fig. 13). It is evident that one of these 

 conditions is readily derivable from the other. Thus, in figs. 12 and 



14, the cytoplasm has separated into a chromophil substance lying 

 within an almost achromatic substance. This latter gradually 

 di-appears, producing the condition shown in fig. 13. 



A high affinity for chromatin stains is characteristic of the by- 

 products of protoplasm, and is especially well brought out by thionin. 

 Thus, in material so stained, both degenerate nuclei and mucus are 

 deeply stained. In the former case we are dealing with a patho- 

 logical, in the latter with a physiological process, but in both with 

 protoplasmic by-products. In the case of these Sarcosporidia, the 

 great increase in the size of the nucleus seems to predicate a supply 

 of pabulum, and the suggestion is at least permissible that this 

 pabulum is supplied by the cytoplasm. If this were so, the presump- 

 tion would be that the densely staining flecks, as noted in figs. 12, 

 13, and 14, represent the cytoplasmic debris remaining after the 

 nucleus has robbed the cytoplasm of a part of its substance. It is 

 of course to be understood that the above is put forth merely as a 

 possibility, the matter being one scarcely open to a rigid demon- 

 stration. 



Mouse 125. — As noted in the list given on p. 6, this mouse repre- 

 sents the conditions from 2 to 2| hours after feeding. These are in 

 all essentials the same as those of mouse 248, as is evidenced by figs. 



15, 16, and 17. In the case of fig. 17, Plate II, it is to be noted that 



2 



