Sod Disease oe Chickens 
5 
the district affected but the disease appears on adobe as well as on 
sandy soil. Furthermore, sandy soil is also present in irrigated dis- 
tricts. Throughout this whole area the sun is extremely hot in 
summer and it is well known that white hogs do not thrive well 
because of the fact that the sun blisters the skin. This theory has 
been given much credence by some, but does not seem in itself tc 
be a sufficient explanation since, in experiments conducted by us, 
the chickens kept on plowed ground in the sun did not develop 
the disease. 
Ants are of course very prevalent throughout the district but 
the evidence for this theory is not conclusive. The presence of cactus 
throughout all of this district and their practical absence in plowed 
ground, early led to the assumption that the spines of this plant 
were responsible for the difficulty. However, in our experiments, 
chickens on cactus alone did not develop the trouble. 
The evidence in favor of the disease being associated in some way 
with sod is considerable. In the first place, the disease has never 
been known on irrigated land, nor does it occur on dry land where 
the sod has been broken up and the fields have been cultivated for 
a few years. We have in our records the outline of one case in which 
a lady lived on an irrigated farm near Fort Collins for several years, 
having no trouble, and in fact being in entire ignorance that there 
was such a disease. During 1916, she moved to a dry hill above 
the ditch, not, however, a half mile distant from her former location. 
There, during the first summer, the disease manifested itself and 
caused a considerable loss. The following year she had the same 
Scabs are falling off and the chicken is making a fair recovery. 
