THE AIR SAC MITE OF THE FOWL. 
23 
half years, property of Experiment Station, procured in Massa¬ 
chusetts in 1894, and was apparently well until about December 
15, 1895, when she appeared dull, inattentive to surroundings, 
comb bluish in color, the anal plumage clean, but there was a 
well-marked diarrhoea present, the faeces being thin, stringy 
and pale yellow, emaciation marked. Killed January 3, 1896. 
The abdominal and diaphragmatic air sacs were found to be 
filled with cytodites. Left abdominal sac contained a patch of 
calcareous deposit, white and opaque, about three-fourths inch 
in area. No further pathological lesions found. 
The geographical distribution of the disease is not well 
known. It has been recognized in various parts of Europe, but 
so far as we know has not heretofore been recorded in America. 
It is, or was, highly prevalent in the Gallatin and Madison 
valleys in Montana, where it constituted a serious scourge to 
poultry, being more or less prevalent in nearly all poultry 
yards, and when not inducing evident illness or death resulted 
in a loss of vigor, the hens ceasing to lay eggs, the cocks be¬ 
coming sterile and external and internal genitals atrophied. 
I also observed the disease in a serious form in the Snake 
River Valley near Idaho Falls, Idaho, and am led to believe 
that it is widely disseminated in the Rocky Mountain States. 
In those localities where the malady was observed, the alti¬ 
tude ranges from 4000 to 6000 feet above sea level, with a very 
low degree of humidity. No reason appeared to indicate that 
the great altitude had any influence in the existence of the 
disease, and the experimental transmission of the parasites to 
healthy fowls at this college and the rapid increase of the mites 
thereby, indicates that if the parasite does not prevail in other 
parts of the country it is more probably due to a failure of in¬ 
troduction than to climatic conditions. 
The natural mode of transmission is unknown, but it can, 
so far as we can see, only occur by the entrance of the mite 
through the nostrils after they have first escaped or been ex¬ 
pelled from the affected bird by sneezing or coughing. There 
being generally a discharge of mucous from the nostrils of af- 
