COCCIDIIDA 



6 9 



its appendages by predilection, but are also found in other organs (kidneys, 

 spleen, ovaries, vas deferens, testicles) ; some also live in the connective 

 tissue of various organs, more particularly of the intestine. 



The knowledge of the development of the coccidia was of particular impor- 

 tance in determining their classification. By means of encysted coccidia 

 from the liver of rabbits, Kauffmann (7) first confirmed the fact that the cystic 

 membrane, which was filled, or partly filled, with granular contents, divided 

 into three or four pale bodies after a long sojourn in v/ater ; Lieberkiihn, how- 

 ever, observed the same process in the host in the case of coccidia of 

 the kidney of the frog. Stieda (8) studied more minutely the alterations that 

 take place within the encysted coccidia of the liver of rabbits after the 

 death of the host ; he discovered that what we at the present day call 

 " spores " were oval formations pointed at the one pole, and surrounded 

 by a delicate membrane, which exhibited a certain thickness at the pointed 

 extremity and enclosed a -slightly bent rodlet, expanding at either end into 

 a strongly light-refracting globule ; a finely granulated globule also lay in the 

 concavity of the bent .rodlet. Waldenburg (9) saw the appearance of the same 

 phenomenon in coccidia from the epithelium of the villi and Lieberkuhn's 

 glands from the intestine of the rabbit ; but the process in this case took 

 place in a much shorter time. 



j$8f 



FIG. 27. Coccidium cumculi (Riv.), from the f^V.'r-^ 

 liver of the rabbit, in various stages of develop- |''J' : S&' 

 ment. 



According to the discovery of Kloss(io), the spores of the coccidia of the 

 urinary organ of the garden snail are formed in far greater numbers ; the round 

 spores also harbour several (five to six) rodlets, which after the bursting of 

 the spore-envelope become free. Eimer's researches have made us acquainted 

 with a coccidium from the intestine of the mouse, which was transformed 

 in toto into a " spore," with sickle-shaped little bodies ; the fact was, 

 moreover, established that the little bodies left the delicate envelope already 

 in the intestine, made crossbow movements, and were finally transformed into 

 amoeboid beings, which apparently penetrated the epithelial cells ; at all 

 events, similar bodies of various sizes were seen in these cells. Taking the 

 immense number of these parasites into account and the lack of any other 

 cause, Eimer attributed the sudden death of his mice to the Gregarina falci- 

 formis, as the parasite was then called, just in the same way as a few 

 years previously Reincke (n) ascribed the acute intestinal catarrh of rabbits 

 leading to their death to the invasion of intestinal coccidia. 



All that had become known about coccidia up to 1879 was then com- 

 piled by Leuckart, and completed by his own observations on the liver coccidia 

 of the rabbit. Experimental infections had already been conducted by Walden- 

 burg with intestinal coccidia of rabbits, and by Rivolta (12) with the coccidia 

 of the fowls, which experiments confirmed the importance of the spores, or 



