CHICKEN CHOLERA . 411 



much more marked, so that 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. 



