282 J. JACKSON CLARKE. 



conclude that the parasites of Eimer (Eimeria, A. Schneider) 

 are the same as those described in this paper. The chief 

 grounds for this conclusion consist in the round form Eimer 

 refers to in many of his parasites^ and to their dimensions, 

 18 ju X 18^ and 26ju x 16 fx, approaching more nearly to the 

 parasites described above than to C. oviform e in the rabbit, 

 where the intestinal parasites average, I have found, 32 ju x 

 22 fx. 



In order to test the transmutability of C. oviforme into 

 Eimeria, I fed two young white mice whose excrement I had 

 found to be free from coccidia with food mixed with the dung 

 of a rabbit containing spore-ripe C. oviforme. The result 

 of these experiments was negative. 



A third experiment gave a positive result. A very old white 

 mouse, whose faeces had been found to contain no coccidia, 

 was given food mixed with some material which had been taken 

 from the caecum of a rabbit, and kept for two months in a 

 moist chamber. There were many spore-ripe coccidia in this 

 material. Five days after the administration of the parasites 

 the mouse died, and its alimentary tract was found to be 

 filled with coccidia like those in the other mice referred to 

 above. 



I may now conclude these observations by indicating the 

 conclusions to which they point. 



Conclusions. 



1. That the Sporozoa described above as they were found in 

 white mice belong to the Coccidiidea, and, like C. oviforme, 

 to the Disporeae. 



2. That they are probably identical with the Sporozoa de- 

 scribed by Eimer in the intestines of mice, and named 

 Eimeria by Schneider. 



3. That Eimeria is probably only a variety of C. ovi- 

 forme, and may be but a modification of C. oviforme 

 (although two out of three experiments made with a view of 

 solving the point gave negative results) determined by the 



