EXPERIMENTAL INFECTION 751 



Experimental infection. 



It is now established that the introduction of the Amoeba kistolytica into 

 the alimentary canal of man, monkeys and young cats reproduces the lesions 

 characteristic of dysentery. 



Many of the early experiments, carried out before the amoeba of dysentery was 

 identified and when the fact that there were several forms of dysentery was unrecog- 

 nized, only gave conflicting results. 



Losch injected recently-passed dysentery stools into the alimentary canals of 

 four dogs : after the lapse of a week amoebae were found in the excreta of one only 

 of the animals : this animal remained in apparently good health, but when it was 

 killed on the eighteenth day the rectal mucous membrane was found to be inflamed 

 and ulcerated in places and the amoebae had multiplied at the site of the ulcers. 



Kovacz produced a blood-stained diarrhoea in a cat by inoculating it in the rectum 

 with dysenteric stools. Kartulis obtained a similar result with one of his straw 

 infusion cultures. Zancarol produced dysentery in a cat by inoculating stools 

 containing amoebae into the rectum ; but he obtained the same result with pus from 

 an abscess of the liver which only contained Streptococci and also with pure cultures 

 of Streptococci. 



Moreover, cats often suffer from an ulcerative colitis resembling dysentery (Gasser) 

 and dogs are liable to a similar disease. The author saw several dogs in Tunis 

 affected with this form of colitis and failed to find amoebae in the dejecta. In the 

 cat rectal injection of irritant substances and especially of sterilized soil produces 

 ulceration of the colon. 



Kartulis infected a cat with amoebic dysentery by inoculating it per rectum 

 with stools from a patient suffering from amoebic dysentery. The same 

 result can be obtained by inoculating pus from an abscess of the liver con- 

 taining amoebae in pure culture (Kartulis, Krause) and by operating in a 

 similar manner an amoebic dysentery which is almost always fatal can be 

 set up in young dogs (Hlava, Kartulis, F. Harris). 



Lesage inoculated 0*5 c.c. of recent dysenteric stools or pus freshly taken 

 from an abscess of the liver and containing living amoeba? into the rectum of 

 young cats. A certain proportion of the animals suffered from symptoms of 

 amoebic dysentery with blood-stained mucus in the stools and died in about 

 12 days or a fortnight. Post mortem, lesions characteristic of dysentery were 

 found (thickening, ulceration and necrosis of the mucous membrane of the 

 large intestine). The parasites may enter the blood-stream. 



Young cats can also be infected by feeding them (or by means of an ceso- 

 phageal catheter) with minced meat mixed with infected stools : to produce 

 infection the stools must contain encysted amoebae (desiccated stools or stools 

 which have been kept for a few hours in a moist chamber). 



Lesage has also infected young cats with his cultures of amoebae (vide 

 ante). 



Musgrave and Clegg by feeding monkeys (Macacus cynomolgus and M. 

 pTiilippinensis] with cultures of amoebae, or by introducing the cultures into 

 their stomachs, set up a typical dysentery with haemorrhagic catarrh and 

 occasionally small ulcers of the colon. A man who had swallowed three 

 gelatin capsules containing a three-week-old culture of an intestinal amoeba 

 together with an harmless bacillus suffered at first from diarrhoea with 

 amoebae in the stools (twelfth day) and later from tenesmus and blood- 

 stained stools (twentieth day). 



Agglutination. The blood of persons affected with amoebic dysentery does 

 not agglutinate the bacillus of Shiga. 



