ASPERGILLOSIS 113 
pergillosis may be expected. As a rule the morbid condition has 
existed for some time before symptoms are noticed. When the le- 
sions are located in the trachea or bronchi, hoarseness of breathing, 
or a rattle in the throat may be the only indication of infection in the 
early stages. In air sac involvement alone no respiratory symptoms 
are shown. It is doubtful if external symptoms of infection of the 
air channels of the bones of the wing are manifested. 
As the disease progresses the bird becomes dull and less active. 
There is a noticeable decrease in weight accompanied by emaciation. 
The term “ going light ” is frequently applied to this condition. Di- 
arrhea is not a constant symptom but is usually present in the later 
stages. Temperature elevation is not constant in the more chronic 
form. Difficult respiration, sleepiness, extreme weakness and marked 
emaciation precede death. The appetite decreases as the disease pro- 
gresses. Death results from asphyxia and toxemia. 
In baby chicks the symptoms are apparent early and are similar 
to those of bacillary white diarrhea and intestinal coccidiosis. In 
both young and old birds the lesions observed at post mortem readily 
reveal the nature of the disease. 
Morbid anatomy. The lesions are principally confined to the 
respiratory system. This system is complicated in birds for in addi- 
tion to the lungs it includes several air sacs in the peritoneal cavity 
and air channels in certain of the bones. In some instances through 
penetration of the walls of blood vessels by the mycelia, new areas 
of infection may be established in other organs as a result of meta- 
stasis. 
The mold may develop at any point on the respiratory mucous 
membrane or may be spread over a large portion of its surface. Our 
observations at numerous autopsies place the abdominal air sacs as 
the most severely involved region. The morbid process is manifested 
by the presence of a membrane of greater or less thickness depend- 
ing on its location on the mucosa, or at times by nodules in the 
parenchyma of the lungs. In the trachea and bronchi the false 
membrane is comparatively thin while in the air sacs it may be 
much thicker and give a rigid contour to these organs. Frequently 
the sacs are filled with fungoid growth and cellular exudate, the 
whole forming a solid mass. The bronchioles may also be plugged 
with mycelia, spores and cellular exudate consisting of exfoliated 
epithelial cells, leucocytes and occasionally red blood corpuscles. 
The surface of the membrane may be grayish or greenish in color. 
The latter color is nearly always in evidence at some point. It is in 
