Sod Disease of Chickens T 
healthy chickens in cages with affected chickens, but in no case 
were we able to show any transference of the disease. Consequently, 
while we still lean to the infection theory, we must admit that our 
experiments have not added any support to it. 
Our investigations are now outlined with the possibility in mind 
that an infection does exist and that it gains entrance through 
abrasions caused by cacti or Russian thistles. For this view, how- 
ever, we have no positive evidence. 
Symptoms — The disease frequently manifests itself during the 
first week of life, its presence being evident to the observer because 
of the fact that the affected chicken becomes dull and remains 
behind the rest of the brood. A close examination at tliis time will 
often reveal the presence of blisters between the toes or possibly 
small scabs on top of the toes and on the lower portion of the leg. 
Scabs have not been found on the under surface of the toe. The 
whole foot is usually swollen and is very tender to the touch. Ow- 
ing to the pain, the chicken sits down a great deal. In the course 
of two or three days the vesicle ruptures and is replaced by a thick 
heavy scab. The toes increase in size and become very rigid. Oc- 
casionally a joint or even a whole toe drops off. If the chicken sur- 
vives, the scabs disappear in the course of two or three weeks longer 
and the toes become extremely distorted, turning usually in an up- 
ward direction so that the only portion of the foot that touches 
the ground is the heel. During the scabby stage, chickens pick at 
the feet a great deal. 
Showing- a moderately bad case in the later stages. 
