DOMESTIC RUMINANTS AND THE HORSE 51 



two ; in goats, nineteen. It is likely that most, if not all, of his 

 species and varieties are genuine. Sometimes, however, one finds 

 what seem to be intermediate forms suggesting that at least some 

 species may fluctuate considerably. One of the authors (Becker) 

 once found a specimen of Diplodinium ecaudatum ecaudatum with 

 the posterior spine forked. It was the only one of this sort among 

 hundreds of its species and variety observed in that one cow. 

 Likewise, Becker and Talbott found Ophryoscolex caudatus in one 

 of twenty-six cattle examined, the only one in which this genus 

 was found at all. In this material we found two or three speci- 

 mens with a rounded posterior end among hundreds bearing 

 spines. The one without spines is supposed to be O. inermis. It 

 may have been mere chance that one cow out of twenty-six 

 examined had two species of this genus, one with the posterior 

 armature of spines and the other without. It is more likely that 

 these two forms were variations of one species. At present the 

 senior author has a goat infected with Epidinium hainatum and a 

 number of other species. Some specimens of this species have the 

 typical small posterior spine. Others have spines ranging from 

 extremely small up to the typical size. Those without spines are 

 not Epidinium ecaudatum ecaudatum because the postanal portion 

 of the posterior end is too wide. 



These observations, and a number of others, suggest that species 

 and varieties may fluctuate considerably. The alternative would be 

 a still greater increase of species and varieties almost without end. 

 It is necessary to know something about the variations within a 

 pure line. This study might be made with cultures from single 

 individuals either in vitro or in vivo. To date no one has succeeded 

 in cultivating any infusorian from the ruminant stomach. It would, 

 therefore, be necessary to infect azoic ^ animals. The method of 

 obtaining such animals will be discussed below. 



There is great need for a method of cultivating the infusoria 

 of the stomach of ruminants in vitro, not only for studies of a 

 genetical nature, as discussed above, but also for the purpose of 

 studying the chemical changes they may produce. Such changes 

 might give some light on the role of these protozoa in the ruminant 

 stomach. Becker and Talbott (1927) made numerous attempts to 

 cultivate them, but failed. Rees (1927) has succeded in cultivating 



' A term coined by Liebetanz for ruminants with no protozoan infection 

 in their stomachs. 



