296 THE PATHOGENIC RHIZOPODA 



intestine, denied the pathogenic character of "Ameba coll," claiming 

 that it is an organism of wide distribution and quite harmless. Casa- 

 grandi and Barbagallo were the first to prove, although not the first 

 to suggest, that the ordinary form of the ameba is harmless, a proof 

 which was confirmed by Schaudinn, who inoculated himself with 

 Entameba coli and without any disturbance, a result which he also 

 repeatedly obtained with young cats. From the medical side Council- 

 man and Lafleur, in 1891, first demonstrated that dysentery is not all 

 one type of disease, and that amebic dysentery is both clinically and 

 etiologically different from other kinds. They suggested the name 

 Ameba dysenteric for the organism causing the intestinal ulcerations, 

 and Ameba coli, Losch, for the harmless form ; but their suggestion was 

 not followed by enough morphological data to warrant the creation of 

 a new species, and zoologists did not accept the new terms. Casagrandi 

 and Barbagallo, working on A. coli, came to the conclusion that the 

 generic name ameba should not be stretched to include forms like 

 Ameba proteus, on the one hand, and these small intestinal parasites 

 on the other, and so called the latter entameba, while the specific name 

 hominis was substituted, without justification, for Losch's term coli, 

 Schaudinn, finally, overlooking Councilman and Lafleur's observa- 

 tions, adopted Casagrandi and Barbagallo's name entameba for the 

 genus, and named the harmless form Entameba coli, and the patho- 

 genic form Entameba histohjtica, a better name, but not prior to 

 Councilman's "dysenteries." 



Entameba coli is widely distributed in the human intestine, this 

 distribution varying with the locality and with the people. Schaudinn 

 found it in about 20 per cent, of the feces investigated by him in Berlin, 

 while in the region about Rovigno, in Istria, he found it in 256 cases 

 out of 385, and other observers have noted a like variation in the per- 

 centage of healthy persons infected. It is an organism to be obtained 

 without much difficulty, and is more prevalent in persons suffering 

 from intestinal disturbances. During the ordinary inactive phases 

 there is little or no differentiation into cortical plasm (ectosarc, ecto- 

 plasm) and endoplasm, but when it moves, a hyaline sheet of proto- 

 plasm moves out from the body, and this is similar to the cortical plasm 

 of fresh water ameba?. This ectoplasm is only momentary, however, 

 for the endoplasm quickly flows into the advanced part. The nucleus 

 is vesicular, with a distinct membrane and with one or more karyo- 

 somes of chromatin and plastin, while the numerous chromatin 

 granules are distributed throughout the space of the nucleus, with a 

 tendency of frequent occurrence among the protozoa to collect at 

 the periphery. The abundance of chromatin makes the nucleus stand 

 out prominently in stained preparations. 



Multiplication of the parasite is accomplished asexually by simple 

 division and by multiple division or spore formation into eight daughter 



