41 8 Journal of Agricultural Research voi. xvni,No. s 



An examination of large numbers of stained slides which were made 

 from several infected insects renders the statement possible that such a 

 condition is of regular occurrence in such insects during the later stages 

 of the incubation period, though it is not possible to state at the present 

 time that every infected cutworm shows this phenomenon. 



When treated with the stains noted above, the fungus cells, or blasto- 

 cysts, are pink. The leucocyte cytoplasm is light blue, whereas the 

 nuclei of the leucocytes are dark blue ; hence the fungus cells are clearly 

 differentiated in the blue-stained matrix of the blood cell cytoplasm. 



The number of blastocysts contained within a single phagocyte varies 

 from I to 15, and so far as can be determined they are in all respects 

 similar to those which occur floating in the blood plasm and may even 

 be seen in the process of budding off new cells (PI, 52, B, a). When 

 gorged with large numbers of fungus cells the phagocytes become abnor- 

 mal in form and size, though the tail-like protoplasmic appendage can 

 usually be recognized. If but one or two fungus cells are inclosed, how- 

 ever, the form of the leucocyte is unchanged, and its cytoplasm seems 

 likewise to be little affected ; for it stains as deeply as in uninfected cells. 

 On the other hand, the cytoplasm of blood corpuscles in which several 

 blastocysts are imbedded seems to be in part destroyed, for it stains 

 feebly. It should be noted, however, that although the nuclei of the 

 infected cells may be compressed or even distorted, they seem, to remain 

 intact, staining brilliantly in all tests. The fact that those leucocytes 

 with large numbers of blastocysts imbedded in their substance seem to 

 show evidence of disintegration, together with the fact that in the many 

 preparations examined no evidence of the breaking down of the blas- 

 tocysts has been observed, renders the conclusion possible that the 

 fungus cells gradually destroy the cytoplasm of the blood cells, which 

 in many cases so completely breaks down that nothing remains. 



Such a sequence of events is not unusual in human diseases. There 

 are many cases on record in which it is evident that the phagocytes fail 

 in their attempt to destroy the invading organism, the latter being the 

 more potent ; but the act of ingestion of the parasite by the leucocytes is 

 considered nevertheless as phagocytosis, though it may be ineffective so 

 far as the destruction of the parasite is concerned. 



In addition to the stained blood smears, paraffin sections were cut of 

 Infected larvae which were killed and fixed in Carnoy's solution. The 

 sections were stained in Erlich's haematoxylin and eosin as before, and 

 in them the phenomenon of phagocytosis was made evident in another 

 way (PI. 52, J, N). 



Complexes such as those referred to are composed of certain coher- 

 ing cells. Those near the center of the mass are more or less fused, or 

 at least are compressed so closely against one another that their indi- 

 vidual identity is hard to determine, though their nuclei remain distinct. 

 Those cells near the periphery of the complex, however, retain their 



