ASPERGILLOSIS 281 
and in solution of bichloride of mercury 1 to 1,000 they are destroyed 
in fifteen minutes. 
Aspergillus fumigatus is differentiated from other species by its 
color in cultures, the high temperature at which it grows, the size of 
the spores and by its pathogenesis. Aspergillus glaucus is the one 
most likely to be confounded with it. It may be differentiated from 
A. fumigatus by its ability to grow at low temperature, its delicate 
green color, the large diameter of its spores—9 to 15 —and its lack of 
pathogenic power. 
The mode of infection is through the respiratory tract. Only a 
small number of the spores inspired are able to reach the alveoli, the 
greater number of them being arrested in the tracheal and bronchial 
secretions. Hildebrant has shown that, having reached the alveoli, 
they penetrate the epithelial lining without difficulty. Both animals 
and man seem to possess immunity to intestinal infection. 
The aspergillus does not form toxins. Its pathogenic power is due 
entirely to lesions produced by the masses of mycelium which cause 
a necrosis of the cells and a leucocytic reaction which diminishes the 
functions of the organs, the final result being an enfeebled condition 
of the animal and a lessened resistance to hurtful influences. When 
fruit hyphe can form, the myriads of spores given off by them may be 
carried to other parts of the organ. In this way the foci rapidly 
multiply and practically the entire organ becomes invaded. The 
opinion held by some authors that in the mould mycoses there is “no 
fructification or actual multiplication” of the infected agent and that 
the “number of the diseased foci corresponds exactly with the number 
of spores introduced,” is erroneous both for the disease naturally con- 
tracted as well as for the experimental form. In the produced 
lesions, fruit formation of the fungus is exceptional. It has been 
observed by Renon to take place only where there is full communica- 
tion with the air. 
Aspergillosis in cattle. Aspergillosis in cattle was described by 
Zin in 1876. In 1900, Pearson and Ravenel described an interesting 
case of ‘_pneumomycosis in a six year old cow due to A. fumigatus. 
This seems to be the only carefully described case of this infection in 
cattle reported in American literature. 
The cow had been in poor condition for six months prior to bringing her to the 
Veterinary Hospital where she was tested with tuberculin with no reaction. At this 
time she did not eat, was weak and depressed, respiration labored and from 40 to 90 
per minute. Pulse rapid. Percussion of the chest walls gave a sound that, if anything, 
