608 AMCEBIC DYSENTERY 



of a small quantity of mucus from a dysenteric case into the 

 rectum. The resulting disease is of an acute character, and 

 sometimes leads to a fatal result. The changes in the large 

 intestine resemble those found in the human disease, and 

 microscopic examination shows the amoebae penetrating the 

 wall of the bowel in the characteristic manner. Kruse and 

 Pasquale obtained corresponding results when the material from 

 a liver abscess, containing amoebae without any other organisms, 

 was injected. Quincke and Roos obtained no effects when 

 the amoebae were administered by the mouth, but they ob- 

 tained a fatal result in two out of four cases when the cyst- 

 like forms were given. They also found that the cysts, unlike 

 the amoebae, were still present even after the material had been 

 kept for two or three weeks. Extremely important confirmatory 

 evidence with regard to infection by the cysts has been supplied 

 by experiments of Schaudinn. Dysenteric material was obtained 

 from China, and portions of it which were found to contain 

 the cysts were thoroughly dried. Some of this material was 

 given with food to cats by the mouth, and typical dysentery 

 resulted, the amoebae being found in the stools. No results 

 follow when the material ingested merely contains the vegetative 

 form of the organism, as it is readily destroyed in the contents 

 of the stomach. 



Musgrave and Clegg produced amoebic colitis in monkeys 

 by means of cysts from cultures, and such results were obtained 

 whatever was the source of the amoebae, that is, with those 

 obtained from water, vegetables, etc., as well as with those 

 from dysenteric material. They also produced liver abscess 

 by direct injection into the liver, and in some instances only 

 amoebae were present in the abscesses. 



Investigations with regard to entamoeba, coli seem to show 

 that it is a harmless organism and that it is frequently present 

 in the intestines of healthy individuals. Schaudinn found that 

 in East Prussia as many as 50 per cent, of the population were 

 infected with it. The administration of the amoebae, or of the 

 cysts by the methods mentioned above, produced no result in 

 animals. It has, however, been shown that when the eight- 

 celled cysts are swallowed by persons who are free from the 

 parasite the entamoeba coli appears in the large intestine in 

 a comparatively short period of time. It accordingly appears 

 that in the case of both organisms it is the cysts alone which 

 give rise to infection. Confirmatory results with regard to 

 the common occurrence of E. coli were obtained by Craig in San 

 Francisco. 



