SPIRILLA RESEMBLING CHOLERA. 343 ilium. At times the growth may be a little more rapid. The growth on agar is very luxuriant, and gives off a pronounced odor of indol. Loffler's blood-serum is ap- parently not a perfectly adapted medium, but upon it the organisms grow, with resulting liquefaction. Upon po- tato at the point of inoculation there is a thin, glazed, more or less dirty yellow, shading to brownish deposit that is sometimes surrounded by a flat, dry, lusterless zone. In litmus milk a slightly reddish tinge is found after twenty-four hours at body temperature. After forty-eight hours this is increased and the milk is coagulated. In peptone solutions indol is produced. No gas is pro- duced in glucose-containing culture-media. The organ- ism is a facultative anaerobic spirillum. The thermal death-point is 50° C. for five minutes. The organism is pathogenic for pigeons, guinea-pigs, and mice. The pathogenesis is much like that of the Spirillum Metschnikovi. No Pfeiffer's phenomenon was observed with the use of the serum of immunized ani- mals. Immunity was produced in pigeons, and it was found that their serum was protective against both the Vibrio Schuylkiliensis and Spirillum Metschnikovi, the immun- ity thus produced being of about ten days' duration. In a second paper by Abbott and Bergy1 it was shown that the vibrios were found in river water during all four seasons of the year, and in all parts of the river within the city, both at low and at high tide. They were also found in the sewage emptying into the river. The spirilla were also found in the water of the Delaware River as frequently as in that from the Schuylkill. One hundred and ten pure cultures of spirilla were iso- lated from the sources mentioned and subjected to routine tests. It was found that few or none of them were iden- tical in all points. There seems, therefore, to be a family of river spirilla related to each other like the different colon bacilli are related.. 1 Journal of Experimental Medicine^ vol. ii., No. 5, p. 535.