ENTAMQEBA HISTOLYTICA 37 



independent of the patients themselves, transmission experiments from cat to cat 

 were performed, after the first experiments on cats yielded positive results. This 

 was also effected by rectal feeding as employed by earlier workers. Such appeared 

 necessary in order to prevent the evacuation of the inoculation material per anum^ 

 as well as to avoid the employment of morphia and ether narcosis. Forty-six 

 cats were used for the experiments. Ten cats received tested stools containing 

 motile amoebae from soldiers suffering from amoebic enteritis contracted in China. 

 Sixteen other cats received stools from cats infected by inoculation. All the animals 

 sickened and suffered from the disease. Five cats received dejecta from human 

 amoebic enteritis in which, however, no motile amoebae were present. Thirteen cats 

 received stools from soldiers who suffered from bacillary dysentery. None of the 

 latter cats took the complaint and none showed changes in the large intestine upon 

 sectioning. The injection of various bacteria, obtained from a stool of amoebic 

 enteritis pathogenic to cats, remained without result in both the cats employed for 

 this experiment. Lastly, two cats, which had been kept with those artificially 

 infected, were taken ill spontaneously and suffered from the disease. In the opinion 

 of Harris, who ascertained the harmless nature of bacteria derived from the 

 intestinal flora containing dysenteric amoebae, young dogs are capable of being 

 infected. 



Within the large intestine an active increase of Entamceba histolytica must occur. 

 Nevertheless, Jiirgens did not definitely find changes that might be interpreted in this 

 sense. Schaudinn (1903) observed division and gemmation in vivo. Both processes, 

 in which the nucleus divides by amitosis, can only be distinguished by the fact that 

 the daughter individuals are similar in binary fission but dissimilar in gemmation, 

 whether they make their appearance singly or in greater numbers. Schizogony, 

 resulting in the formation of eight individuals, which is so characteristic for Ent- 

 amceba coli, was not observed. (But schizogony, into four merozoites, is now known 

 to occur. Gemmation processes are apparently degenerative.) 



Resistant stages, which serve for transmission to other hosts, are according to 

 Schaudinn 1 first formed when the diseased portions commence to heal, or more 

 accurately, the recovery commences when the vegetative increase of the amoebae in the 

 intestine discontinues. The so-called spores of E. histolytica were distinguished very 

 definitely from those of E. colt ; they were said to consist of spheres of only 3 to 

 7 /j. in diameter, which were surrounded by a double membrane, at first colourless, but 

 becoming a light brownish yellow colour after a few hours, and possessing a protoplas- 

 mic content containing chromidia. They were said to arise by fragments of chromatin 

 passing outwards from the nucleus of the amoeba into the surrounding cytoplasm 

 (fig. 9, a) and undergoing so marked an increase that finally the whole cytoplasm 

 became filled with chromidia. The remainder of the nucleus underwent degenera- 

 tion and became extruded. On the surface of the cytoplasm there then arose small 

 protuberances containing chromidia. These processes had been observed in the 

 living organisms. They gradually divided and separated from membranes which later 

 became yellow. The remainder of the amoeba perished. Craig 2 had also seen phases 

 of this process of development. It must be remarked that, according to recent 

 researches, these processes of exogenous sporulation are degenerative in character (see 

 p. 41). The small spores may be fungi. The " sporulation " processes are only men- 

 tioned here as a warning. They are now only of historic interest. By means of an 

 experiment made on a cat, Schaudinn ascertained that ingestion of permanent cysts, 

 which resist desiccation, is the cause of the infection. The animal took food containing 

 dry faeces with amoeba cysts ; these fasces came from a patient suffering from amoebic 



1 Arb. a. d. kaiserl. Gesundheitsamte, xix, pp, 547-576. 



2 " Life cycle of Amoeba colt in Human Body," American Medicine, 1904, vii, p. 299 ; viii, 

 p. 185. 



