Kartulis continued the work of Koch and in 1886 published his findings in 150 cases of dysentery, noting the presence of amoebae in the stools of all these cases. In 1887 he noted the presence of amoebae in liver abscess. In 1891, Lutz noted that amoebae in dysentery contained red cells. In the same year Councilman and Lafleur came to the conclusion that there were two species of amoebae in man, one harmless and the other, which was found in the submucosa of intestinal ulcers, pathogenic, Casagrandi and others put forward the view that amoebae only acted as carriers for bacteria, but in 1893 Kruse and Pasquale injected all the bacterial species isolated from a dysenteric stool into a cat’s rectum with negative result. Hlava and Kartulis first produced dysenteric lesions in cats by injecting per rectum, amoebic stools. Kruse and Pasquale produced dysentery in cats by injecting per rectum bacteria-free pus from a liver abscess which however contained amoebae. A stumbling block as to the connection between amoebae and dysentery was the fact that many cases of typical dysentery failed to show amoebae. In 1898 Shiga settled this matter by reporting a group of bacilli which were concerned in the production of dysentery. His findings were confirmed all over the world and the distinction gradually obtained of cases of dysentery from bacillary as well as from amoebic infections. In 1903 Schaudinn reported the existence of two species of amoebae, one harmless and named _Entamoeba coli_, the other pathogenic and named _E. histolytica_. In 1907 Viereck described a pathogenic amoeba which, by reason of its four nuclei in the encysted stage, he called _E. tetragena_. As the result of the work of Hartmann, Whitmore, Darling, Wenyon and the recent conclusive findings of Walker we now hold the view that Schaudinn was working with _E. tetragena_ and not with a separate species, so that by the law of priority we must drop the name _E. tetragena_ and accept _E. histolytica_. =Geographical Distribution.=—Amoebic dysentery seems to be especially prevalent in Indo-China, China and the Philippines, as well as in parts of India. It is also very common in Egypt and Northern Africa. In South America, especially Brazil, it is common, as is also true of the West Indies and Central America. It is an important disease in the Southern States of the United States, as well as in Italy and other parts of Southern Europe. On the whole it is probable that it exists in greater or less degree in most of the tropical and subtropical parts of the world. ETIOLOGY AND EPIDEMIOLOGY