68 THE AMOEBAE LIVING IN MAN 



appear to mean by this that they simply observed " periods of apparent 

 health alternating with acute relapses " — a very different thing from the 

 true carrier condition seen in man. 



Cutler (1918) somewhat casually mentions that he found "a few 

 cysts " in two experimental cats (Nos. 1 and 2), although his account of 

 the second animal makes it probable that it was never really infected with 

 E. histolytica. In a more recent paper (Cutler, 1919) he says : " in the 

 cat's gut cyst formation probably never occurs" (p. 131); again, "in 

 cat infections, . , . cyst formation ... is rare " (p. 140) ; and again, 

 "If Dale and Dobell mean . , . that they found no evidence of cysts 

 (sic) formation in cats, I am in entire agreement." Cutler has thus twice 

 asserted and twice denied that cysts are formed in the cat. This seems 

 to me sufficiently contradictory to render further criticism superfluous. 



Amoebic abscess of the liver has been produced both in dogs and in 

 cats, as a sequel to intestinal infection. It was first produced experi- 

 mentally in the dog by Harris (1901), and Kartulis (1913) has recorded 

 a spontaneous case. Craig (1905), Werner (1908), Huber (1909), Wenyon 

 (1912), Dale and Dobell (1917), and others, have observed amoebic liver 

 abscesses in cats. The first case was probably Huber's, though not the 

 first to be described. Kartulis (19 13) states that he has seen a case of 

 spontaneous amoebic dysentery and liver abscess in a badger, and this 

 may have been due to accidental infection with E. histolytica. In the 

 cat, the amoebic liver abscesses closely resemble the early abscesses seen 

 in man. 



Although carnivores seem most easily infected with E. histolytica, 

 there is now evidence that rodents can also harbour the parasites. The 

 most interesting case is that of the guinea-pig. Kartulis (1886), Hlava 

 (1887), Kruse and Pasquale (1894), and Werner (1908), were unable to 

 infect this animal; but Baetjer and Sellards (1914^) and Chatton (1917(7, 

 1918, 19186), have since succeeded. From the observations of these 

 workers it appears that E. histolytica infection in the guinea-pig is not 

 accompanied by dysentery. It is sharply localized in the caecum, where 

 it gives rise to remarkable lesions resembling neoplasms, and described 

 by Chatton as a " lympho-sarcomatoid hyperplasia." The infection can 

 be brought about by cysts per os or by amoebae per annm (Chatton), as 

 in the cat, and it appears to be usually fatal to the guinea-pig. A fuller 

 account will be found in the papers cited. It only remains to add that 

 " amoebiasis " in the guinea-pig appears to be a disease of a type different 

 from the dysenteric infections of man and carnivores. Whether it is 

 ever paralleled in human beings remains to be seen. Possibly some 

 cases of " latent amoebiasis " in man are of a similar character. No 

 cysts of E. histolytica have yet been described, however, from the faeces 

 of infected guinea-pigs. And it is worthy of note that this animal has 

 an amoeba* of its own, resembling E. coli and E. mnris, Leger (1918) 

 has recently given an account of an epizootic, believed to be due to 

 intestinal amoebae, among guinea-pigs in Cayenne (Guiana). The 

 reasons for connecting the amoebae with the disease are, however, far 

 from obvious, and certainly inconclusive. 



Kartulis (1886), Hlava (1887), Dale and Dobell (1917), and others 



♦ Cf. Chatton (1917a), etc. This organism was probably first noted by Walker 

 (1908). Its correct name appears to be Entamoeba cobayae Walker emend. Chatton 

 (syn. E, caviae Chatton, 1918 b)—\l really a distinct species. 



