EXPERIMENTAL INOCULATION 541 



admixture of blood in varying amount. Microscopic examination 

 shows chiefly necrosed and granular cells and debris resulting 

 from their disintegration, whereas ordinary pus corpuscles are 

 scanty or may be practically absent. In such abscesses associated 

 with dysentery the amoebae are usually to be found, and not 

 infrequently are the only organisms present, no cultures of 

 bacteria being obtainable by the ordinary methods (Fig. 167). 

 They are most numerous at the spreading margin, and this 

 probably explains a fact pointed out by Manson, that examination 

 of the contents first removed may give a negative result, while 

 they may be detected in the discharge a day or two later. The 

 action here on the tissues is of an analogous nature, namely, a 

 necrosis with softening and partial liquefaction, attended by 

 little or no suppurative change. The amoebae have also been 

 found in the sputum when a liver abscess has ruptured into the 

 lung, as not very infrequently happens. Kartulis records two 

 cases of brain abscess occurring secondarily to dysentery in 

 which numerous amoebae were present. 



Experimental Inoculation. The anatomical changes in 

 dysentery, as above described, gives strong presumptive evidence 

 as to the causal relationship of the amoebae, and practically con- 

 clusive evidence is afforded by animal experiments. Dysentery 

 occurs occasionally in animals, but it is of rare occurrence. The 

 disease sometimes results in the dog by experimental inoculation 

 with dysenteric material. Kartulis, for example^ records two 

 cases, in one of which liver abscess was present. Cats are, 

 however, found to be more susceptible, especially young animals. 

 Dysenteric changes have been produced in this animal by 

 Kartulis, Kruse and Pasquale, and others. The method generally 

 adopted is the introduction 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 Koos obtained no 

 effects when the amoebae were administered by the mouth, but 

 they obtained 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 



