490 DYSENTERY. 



animals. Not infrequently death follows. Kruse and 

 Pasquale obtained corresponding results when the material 

 from a liver abscess containing amoebae without any other 

 organisms was injected. In the absence of cultures of 

 amoebae outside the body, this evidence must be taken as 

 conclusive that the disease produced in cats is really caused 

 by the amoebae. Similar injections with material contain- 

 ing amoebae derived from other sources, is unattended by 

 any pathogenic effects of similar nature. Feeding the 

 animals with material containing the amoebae is much 

 more uncertain in its effect. Quincke and Roos obtained 

 no effects when the amoebae were administered, but they 

 obtained a fatal result in two out of four cases when the 

 cyst-like forms were given. From this fact they infer that 

 the latter are probably a cystic stage of the former and that 

 the former are destroyed in the gastric contents. This 

 practically forms the only important evidence that a cystic 

 stage of the organism has really been observed. These 

 observers found that the cyst-like bodies were still present 

 even after the material had been kept for two or three 

 weeks. 



From the above facts, all of which have received ample 

 confirmation, with the exception of the statements regarding 

 the cyst-like forms, there can be practically no doubt that 

 the amoebae described are the causes of the form of 

 dysentery with which they are associated. We are still 

 ignorant, however, as to their life -history outside the 

 body, and the modes by which infection is produced. 

 Further, in any case where they act as the primary agent, 

 secondary inflammatory changes in the intestine may be 

 produced by the action of various bacteria. 



Varieties of Dysentery. We have already pointed out 

 that all dysenteric conditions are not of the same nature, 

 and that in certain forms amoebae are not present. Ogata, 

 for example, investigated an extensive epidemic in Japan 

 without detecting amoebae. He found, however, in 

 sections of the affected tissues enormous numbers of 

 small bacilli about the same thickness as the tubercle 



