228 DISEASES OF DOMESTICATED BIRDS 
moisture. Inundations and extension of irrigation systems may 
spread the infection to new foci. On some of the infected farms 
cited by Theiler the infection seems to have first attacked cattle. In 
one case the infection had been introduced by cattle. In other out- 
breaks, ostriches died occasionally, while horses and cattle escaped. 
Every precaution should be taken to prevent the exposure of an- 
thrax-infected blood to the air. Under such conditions spores form, 
which are capable of remaining alive in the soil for an indefinite 
period. 
ASPERGILLOSIS IN ADULT OSTRICHES 
Walker has observed that in adult birds, marasmus is the only 
sign of aspergillus infection. When the lungs are affected, respira- 
tion is accelerated and the beak is kept partly open. There is pro- 
nounced loss of condition when the liver is involved. The disease 
usually runs a sub-acute or chronic course. 
The lesions are found to be more or less generalized, the liver and 
respiratory tracts being most generally involved. Degenerative 
changes in the tubercles and destructive changes in the surrounding 
tissues are marked. The tubercles may exhibit the various changes 
in the evolution of a tubercle, such as miliary granulations, caseous 
degeneration and fibrous transformation. The lesions in the liver 
usually consist of extensive caseous areas caused by the degenera- 
tion of agglomerated tubercles and by necrosis of adjoining liver 
tissue. 
Aspergillosis in the adult ostrich as reported by Jowett may pre- 
sent a condition very closely simulating miliary tuberculosis of the 
lungs. The lungs are consolidated, dark red in color, and are filled 
with yellowish-white miliary tubercles about the size of a pinhead, 
which stand out prominently against the background of congested 
and hepatized lung tissue. The tubercles are not readily removed 
for the periphery of each is united to others. They are fibrous and 
shot-like in consistency. They show no evidence of caseation nor 
calcification. There is slight thickening of the pleura, and a few 
nodules are present, but no lesions are observed in the mucosa of the 
trachea and bronchi. 
Examination for tubercle bacilli yields negative results, but mi- 
croscopic examination of crushed nodules in caustic potash reveals 
the true nature of the infection. 
Study of sectioned specimens shows that each nodule is composed 
of: (1) an unstained or very faintly stained central area, (2) sur- 
