AVIAN TUBERCULOSIS 89 
common that coincidences may occur. The literature of tuber- 
culosis reveals comparatively few instances in which avian tubercle 
bacilli have been found naturally in cattle or in man. 
With the exception of the intertransmissibility of avian tuber- 
culosis between pigs and fowls, the disease in fowls stands by itself 
as an economic and hygienic problem. There is considerable evi- 
dence that parrots and canaries may be infected from a mammalian 
source. 
While pigs undoubtedly contract tuberculosis most frequently 
from bovine sources, they do to a lesser extent acquire it from avian 
sources. The possibility of the transmission of tuberculosis between 
pigs and fowls should not be overlooked in connection with hygienic 
measures against the disease in either. Outbreaks of avian tuber- 
culosis in pigs in contact with infected fowls have been observed 
both in Denmark and in the United States. Eastwood and Grif- 
fith made cultures from a series of seventy-eight pigs exhibiting 
only localized tuberculosis. The avian tubercle bacillus was found 
alone in twenty-six of these pigs, or thirty-four per cent. Of the 
remainder, the avian organism was found to be present along with 
bovine bacilli in two cases. 
Symptoms. Until the disease has developed sufficiently to cause 
emaciation, there aré no characteristic symptoms, except in the rare 
cases when the skin or joints are involved. In the latter case poul- 
trymen describe the condition as rheumatism. This term as applied 
to a disease in birds is practically synonymous with arthritis. An- 
emia and emaciation are constant in advanced cases, the latter be- 
coming extremely marked. The loss of weight is very noticeable; 
the bird becomes weak and moves about very little. This disin- 
clination to move may be due either to extreme weakness or, more 
rarely, to involvement of the joints. Under such conditions, the 
bird spends much of the time in a crouching position. An unnatural 
character of the gait is noticeable. 
The eyes are bright and appetite remains markedly good in ad- 
vaneed cases. The skin and visible mucose are pale, and the 
feathers are ruffled. The temperature is usually within the normal 
range, and rarely is subnormal. Young birds affected with the dis- 
ease enough to show symptoms are not encountered, doubtless due 
to the time necessary for the development of serious lesions. 
The separation of deaths from one another in point of time is a 
characteristic feature of the disease. 
Morbid anatomy. -Emaciation is striking in most cases that 
