406 SPECIFIC MICRO-ORGANISMS 



The belief that amebae bear a causal relation to dysentery is 

 based upon the fact that certain types of amebae, E. tetragena 

 (and E. histolytica?) are found in the stools, as a rule, only in 

 cases of dysentery; further, that these cases of dysentery, in 

 which these amebae occur, are characterized by definite clinical 

 signs and typical anatomical changes in the intestine; and that 

 these amebae are found penetrating deeply into the mucosa of 

 the intestine, and it is possible to produce ulcerative enteritis 

 in experimental animals by injecting feces containing amebae 

 into the rectum or by feeding fecal material containing cysts; and 

 further, the fact that abscesses occur in the liver in amebic dysen- 

 tery, in which the amebae are present and in which it has been 

 impossible to demonstrate the presence of bacteria. The causal 

 relation seems highly probable, but it must be recognized that 

 the evidence is very inconclusive and admits of other possible 

 explanations. Even the relationships of the various forms seen 

 in the microscopic preparations require a certain amount of specu- 

 lation for their determination, and the possibility of error, even 

 by the experienced protozoologist, must be recognized and has 

 been well illustrated by the divergent views of Schaudinn and of 

 Hartmann in studying the same slides. Greater certainty would 

 doubtless be derived from the study of artificial cultures if such 

 could be made available. 



Numerous cultures of amebae have been obtained from the 

 stools of cases of dysentery, and some from the pus of amebic 

 abscesses of the liver, the growth taking place on agar in the pres- 

 ence of a single species of bacteria. With these cultures it has 

 been possible to cause enteritis in monkeys. Such cultures have 

 also been grown at 37 C. by A. W. Williams 1 in pure culture on 

 agar streaked with brain substance and with blood, and in these 

 cultures she finds that the amebae approach in their structure 

 the typical entamebae, not only in nuclear structure and cyst 

 formation, but also in the utilization of red blood cells as food. 



1 Soc. Amer. Bact., New York Meeting, Jan. 2, 1913. Science 1913; Vol. 

 XXXVIII, p. 451; Williams, A. W., and Calkins, G. N., Journ. Med. Rsch., 1913, 

 Vol. XXIX, pp. 43-56. 



