762 SUMMARY OF CUEEENT EESEAECHES RELATING TO 



the Coccidia goes on in this case also in the bile-ducts which become 

 converted into knots, as may be determined by careful examination of 

 sections. The earliest stages of development which are met with in 

 the ejiithelial cells are roundish non-cuticulated masses of protoplasm 

 •009 to '01 mm. in diameter. Although in most cases but one 

 intruder is to be found in each epithelial cell, two are not at all 

 uncommon, and from five to six are occasionally observed. By the 

 development of the Coccidia and the active multiplication of their cells 

 the epithelium is greatly modified, for the cells become changed into 

 roundish mulberry- shaped balls, Avhich lie in a thick layer on the 

 connective-tissue wall of the cavity of the knot. 



The Coccidia become transformed also into the slender encapsuled 

 forms described above and foxmd within the epithelial cells, and 

 after passing into a free condition in the interior of the knots, 

 undergo transformation into the ventricose stage. No further de- 

 velopment within the host has been observed in the case of Coccidiiim 

 oviforme, but it may be assumed with probability that a certain 

 nmnber of this parasite at this stage of development find their way 

 to the exterior by the gall- and bile-duct and the intestine. Since the 

 investigations of Kauffmann it has been known that Coccidia undergo 

 further development in water apart from the body. This develop- 

 ment appears to require several weeks or months for its comj^letion, 

 at any rate in the case of the Coccidia of the liver. This further 

 development or formation of spores (which may also be termed 

 formation of Psorospermife, seeing that these spores are comparable 

 only with the true Psorospermias) is effected by division of the 

 contents of the Coccidium into four balls ; it is doubtful whether 

 this is the result of successive dichotomous divisions or of a 

 division into four at one stroke. Each of the four segmentation 

 spheres thus produced excretes a delicate investing envelope, and 

 forms besides a C-shaped rod which lies at the periphery, accom- 

 panied by the remains of the granular mass (comparable to the 

 " Nucleus de reliquat " of Schneider). 



Coccidia which have reached this developmental stage are regarded 

 by Leuckart as fitted to cause infection when taken up by their 

 proper host ; from analogy afforded by kindred animals, he looks on 

 the C-shaped rods as the true germs, but endeavours to explain the 

 further development of the spores observed by Waldenburg and 

 Eivolta as phenomena of decomposition. Neither the spores nor 

 their C-shaped germs were ever observed to leave the body of the 

 host. 



Consideration of the Coccidia (Eimeria A. Schneider), described 

 by Eimer from the intestine of the common mouse leads Leuckart 

 to the conclusion that we have here a form which is probably 

 specifically distinct from Coccidium oviforme, and that in all pro- 

 bability the intestinal species observed in other Mammalia do not 

 agree specifically with those found in the liver ; he therefore proposes 

 the name Cocc. perforans for those of the intestine. Leuckart is 

 enabled by his own investigations to add two cases of the occurrence 

 of C. oviforme in man to those already known. The rabbit is un- 



