CHICKEN CHOLERA. 411 much more marked, so th^at the growth resembles a nail with a pretty good-sized flat head. If, instead of a punc- ture, the inoculation be made upon the surface of ob- liquely solidified gelatin, a much more pronounced growth takes place, and along the line of inoculation a dry, granular coating is formed. This growth is quite similar to that upon agar-agar and blood-serum, which growths are white, shining, rather luxuriant, and devoid of char- acteristics. No growth occurs in the absence of oxygen. Upon potato no growth occurs except at the incubation temperature. It is a very insignificant, yellowish-gray, translucent film. The introduction of cultures of this bacillus into the tissues of chickens, geese, pigeons, sparrows, mice, and rabbits is sufficient to produce fatal septicemia. Feeding chickens, pigeons, and rabbits with material infected with the bacillus is also sufficient to produce the disease with pronounced intestinal lesions. Guinea-pigs usually seem immune, though they succumb to very large doses, especially when given intraperitoneally. The autopsy shows that when the bacilli are intro- duced subcutaneously a true septicemia results, with the addition of a hemorrhagic exudate and gelatinous infil- tration at the seat of inoculation. The liver and spleen are enlarged; circumscribed, hemorrhagic, and infiltrated areas occur in the lungs ; the intestine shows an intense inflammation with red and swollen mucosa, and oc- casional ulcers following small hemorrhagic spots. Peri- carditis is of frequent occurrence. The bacilli are found in all the organs. If, on the other hand, the disease has been produced by feeding, the bacilli are chiefly to be found in the intestine. Pasteur found that when pigeons were inoculated into the pectoral muscles, if death did not come on rapidly, portions of the muscle (sequestra) underwent degeneration and appeared anemic, indurated, and of a yellowish color. The bacillus of chicken-cholera is one whose peculiar- ities can be made use of for protective vaccination.