218 COCCIDIUM OVIFOJIME. 



without having seen either. But the negative result is not decisive, 

 and the less so since the conditions in which we should expect to find 

 movement are not by any means identical with those which obtain 

 in our incubating apparatus and infusions. But there are many 

 parasites of whose vital energy and mobility we should form quite a 

 false impression if we confined ourselves solely to the observation of 

 the animal outside its host, especially if that host be a warm-blooded 

 animal. 



In support of my opinions in regard to the reproduction and de- 

 velopment of Coccidium ovifornie, I may finally refer to the observa- 

 tions which Eimer has made on the intestinal Ooccidia of the mouse, ^ 

 a form which cannot, however, as it is by Eimer, be directly identified 

 with the hepatic Psorosperm. 



In the intestine of the infected mice, which seemed almost synony- 

 mous with all the mice of that locality, Eimer found a great number of 

 small sickle-shaped curved creatures of from 0-01 to 0'016 mm. in size, 

 with a generally homogeneous shining appearance, and at most con- 

 taining extremely fine granules. In size, form, and structure they 

 were most undeniably like the transparent rods above described. 

 Sometimes these were surrounded by a spherical, delicate membrane 

 (O'Oll mm.), which (Fig. 113, B-F) enclosed six or eight in an often 

 regular arrangement ; but, as a rule, they were free and isolated, and 

 in continual motion. They bent stiftly together, and stretched them- 

 selves again, sometimes more quickly, sometimes after longer intervals, 

 and finally, they assumed under the eye of the observer, by contract- 

 ing and rolling up, the form of a clear homogeneous ball, about the 

 size of a white blood corpuscle, and exhibiting an amoeboid move- 

 ment (Eig. 113, G). Such balls were seen in hosts in the mucus, and 

 also inside the epithelial cells of the intestine. Besides these, still 

 larger cells were to be seen, with nucleus and finely granular contents. 

 They passed on the one side through a series of intermediate forms 

 into the homogeneous balls, and, on the other hand, they might be 

 traced through all the stages of development to the adult, round 

 (O'OIS mm.) or ovoid (0'026 mm. long, by 0-016 mm. broad) Fsoro- 

 spermim. The latter contain sometimes scattered, sometimes aggregated 

 contents, as in Coccidiwm oviforine, and were, like them, provided with 

 a smooth, double contoured shell, sometimes with a recognisable micro- 

 pyle at each end. Eimer sees in these " Psorospcrmim " the encysted 

 stage of a Gregarinoid parasite, which he calls Ch-egarina, in reference 

 to the appearance of the young forms. 



The dung of these mice contained, besides the usual forms of Psoro- 



1 " Ueber die ei- oder kugelforniigen aog. Psorospermien der Wirbelthiere :" Wiira- 



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