220 COCCIDIUM OVIFOKMK. 



thus result, in spite of all other analogies, such considerable differ- 

 ences between Eimeria and Coccidium oviforme that an identification of 

 the two seems quite impossible. 



In view of this fact, the question presses, whether the Coccidia ob- 

 served in the intestine of other Mammalia the dog, cat, rabbit, and 

 man are not perhaps also different from Coccidium oviforme, found 

 in the liver of the rabbit ? Hitherto these organisms have been con- 

 sidered as quite identical or as but slightly different. They were all 

 nothing else than " oval or spherical Psorospermice" But that is of 

 course no reason for at once regarding them as specifically identical. 

 Even the common body-form and the similarity of the parasitism are 

 not enough ; the same might be said of Eimeria, but if Eimer's observa- 

 tions be correct, it is a separate form. It is true that such peculiari- 

 ties of reproduction and development as Eimer described in Eimeria 

 are not to be observed in the intestinal Coccidia of the other Mammals. 

 In fact, the latter agree closely, so far as we know, with Coccidium 

 oviforme, so that we have hitherto ranked them together without 

 scruple. 



But none the less does the identification of intestinal and hepatic 

 Coccidia seem to me unwarranted, or even, to tell the truth, improbable. 



I have previously noted the differences which obtain between 

 them in the duration of their period of incubation the former require 

 hardly as many days as the others weeks. The suggested explanation 

 of this difference has also been noticed, but this could hardly be a suffi- 

 cient explanation when the two forms were regarded as identical, while, 

 on the other hand, their divergent habit makes further discussion un- 

 necessary. It must also be remembered that the Coccidia in question 

 (both of course in their encysted stage) differ not inconsiderably in 

 size. While the hepatic Coccidia are described by all investigators as 

 bodies 0*015 mm. broad by 0*032 to 0*037 mm. long, the dimensions 

 of the intestinal Coccidia in the rabbit (according to Keincke and 

 Neumann, the only investigators who give measurements) are 0*024 

 mm. long by 0*0128 to 0*012 mm. broad. Thus the latter are very 

 decidedly smaller than the former. Finally and this fact is very im- 

 portant for the decision of the question there is no case known 1 in 

 which the two kinds of Coccidia have been found beside one another 

 in the same organism, 2 although that ou<jht surely to be very frequent, 

 if not constant, if the same germs were able to develop either in the 

 intestine or in the bile-ducts. 



1 In the eases of intestinal Coccidia, mentioned by Reincke, Waldenburg, and Klebs, 

 the absence of hepatic Coccidia is expressly stated. 



2 This does not in any way contradict the possibility of the two forms occurring in the 

 same organism, indeed this no doubt frequently occurs. 



