DOMESTIC RUMINANTS AND THE HORSE 55 



is the pathogenic one par excellence; Eimcria smithi, the ovoid one, 

 probably not of cHnical importance ; and Eimeria ellipsoidalis, 

 with predominating ellipsoidal cysts, also probably not pathogenic. 

 Sheep and goats likewise have their coccidia, each with probably 

 several species. It seems extremely possible that some of the cattle 

 coccidia may grow in sheep and goats, and vice versa. Cross-infec- 

 tion experiments should be made in order to determine their inter- 

 relationships, and it is extremely important that this be done. It is 

 even possible that pig coccidia are from ruminant sources. 



It is a problem by itself to determine whether E. sinithi and E. 

 ellipsoidalis are non-pathogenic. If they should prove to be rela- 

 tively harmless, it would be extremely interesting to know if an 

 animal which had recovered from an infection with one of them 

 would show increased resistance to E. ziirni, the pathogenic spe- 

 cies. This is not to be expected from what is known about other 

 diseases, but the matter is worth investigating. 



The coprozoic flagellates found in cultures from feces are an 

 interesting group. Prole ptomonas fcecicola Woodcock, 19 16, has 

 a special interest because it is so nearly related to the genus Her- 

 petonionas, found in insects. It would be interesting to know if 

 it will develop in the intestines of flies. A good morphological study 

 of it in culture would also be a contribution. One of the authors 

 found a HerpetoJiionas-UkQ flagellate in the rumen of the first goat 

 examined. The flagellate has not been found again, and nothing is 

 known about its morphology or relationships. Perhaps someone 

 will encounter it again. 



PROTOZOA OF HORSES 



It will be remembered that the rumen or paunch of the ruminant 

 stomach is the large reservoir for plant food in which cellulose 

 digestion takes place. The horse, another herbivorous animal, 

 seems to require also a large reservoir for the breaking down of 

 plant fiber. Instead of an esophageal enlargement the horse is 

 equipped with an enormous cecum and large colon. Like the 

 rumen, the cecum and large colon are teeming with infusorian life 

 and bacteria. Some flagellates and amcebae may also be present. 



The INFUSORIA of the horse are not so well worked up as those 

 of ruminants. There is need of much more descriptive work. Mate- 

 rial can usually be obtained from a rendering works where old 

 horses are bought and killed. The contents of the cecum and large 



