BACILLARY WHITE DIARRHEA 69 
streak is produced along the line of inoculation. In litmus milk little or 
no apparent change occurs within the first forty-eight hours, after which 
the milk becomes slightly acidified without any signs of coagulation of 
the casein. 
“Gas production in sugar bouillon. Negative results were obtained 
with maltose, lactose, saccharose, inulin, and dextrin bouillon. Dextrose 
and mannite were attacked, however, with both acid and gas production. 
In the dextrose fermentation tubes about twenty per cent of the closed 
arm was filled with gas, and the mannite tubes averaged about the same. 
The gas consisted of Co, and H in the ratio of 1 :3. 
“Indol and nitrite production. Neither indol nor nitrite could be ae 
tected in Dunham’s peptone solution at the end of one week’s growth in the 
ineubator.” 
Toxin production. B. pullorum has been shown by Smith and 
Ten Broeck to produce a toxin fatal to rabbits. Filtrates of bouillon 
cultures when injected intravenously may cause death within two 
hours, or marked dyspnea followed by death over night, or cause loss 
of weight followed by recovery. The lesions induced, include con- 
gestion of various organs such as liver, spleen, kidneys, adrenals, 
lungs and mesenteric lymph glands together with hemorrhage into the 
gastric mucosa. 
Source of infection. Infection may occur in several ways. 
The most common source is through infected eggs. It has been 
demonstrated that affected chicks which survive the disease fre- 
quently retain the causative organisms in the system and later, in 
the event that the ovary becomes infected, pass them off in the eggs. 
Many infected eggs fail to hatch, the embryos dying in the shell at 
an early or late stage of development. Should one or more chicks 
be hatched, harboring the disease, the others of the lot are exposed 
early and nearly all become affected. The chicks are especially 
susceptible during the first 48 hours of life, but are practically in- 
susceptible after the third day. Another source of infection is 
through brooders and incubators that have previously held infected 
chicks. ‘Day-old chicks frequently carry the disease to other points 
and contaminate brooders or infect other chicks with which they 
come in contact. However, the largest percentage of outbreaks is 
traced directly to the presence of infected hens in the flock from 
which the eggs for hatching were derived. There is a well defined 
cycle through which the bacterium passes; namely, from the in- 
fected ovary of the hen through the egg to the chick and back to the 
ovary of the pullet which has survived the disease as a chick. 
Pathogenicity. Susceptibility to infection bears a remarkable 
