Zool— Vol. I.] EISEN— PLASMOCYTES. 41 



centrosphere. In fact the whole progressive movement 

 of the archosome, from the base of the bud (plasmocyto- 

 blast) to its center or upper part, must be ascribed to such 

 amceboid movements as those indicated in the figures. 

 Similar forms indicating amoeboid movements of the micro- 

 centrum have been described by Rawitz in his paper, 

 " Untersuchungen uber Zelltheilung," and are illustrated 

 principally in figs. 2 and 3 of said paper. In these and 

 other figures in that paper we also find the granosphere 

 clearly delineated and described as " Zellsubstanzhof." 



Growth and Phagocytosis. — While a large number of 

 plasmocytes are not any lai-ger than the largest divisions of 

 the plasmocytoblasts, many of them are much larger than 

 any that I have seen while yet enclosed in the plasmocyto- 

 blast. From this I infer that the plasmocytes increase in 

 size — that they actually grow. Between the smallest plas- 

 mocytes and the largest ones there are those which are of 

 all intermediate sizes. I have measured plasmocytes which 

 were as large as the nucleus of the fusiform corpuscle, 

 but the majority are much smaller, as will be seen by the 

 measurements given further on. This growth can hardly 

 be caused by anything but an assimilation of food. The 

 food supply is probably mostly derived from the blood serum, 

 but some of it, at least, is at times attained by a direct process 

 of phagocytosis. Thus I have frequently encountered plas- 

 mocytes which had engulfed small erythrocytes or their frag- 

 ments, some of the latter appearing to be in a state of 

 decomposition. On every cover glass such examples of 

 phagocytosis are often found. In fig. 79 I have represented 

 a phagocyte which has swallowed a very small erythrocyte, 

 the more interesting because this erythrocyte contains a 

 parasitic protozoa, the life history of which I will soon de- 

 scribe. In many instances, however, what appears to be 

 phagocytosis is not really so. We frequently find that a 

 plasmocyte overlaps, or is superposed, on a red corpuscle, 

 in which case it at first appears as if the plasmocyte was 

 in the act of digesting- the red cell. All around the out- 

 lines of the plasmocyte there is seen a pale margin, as if 



