ON 
DEMODEX PHYLLOIDES, (CSOKOR,) 
IN THE SKIN OF CANADIAN SWINE. 
BY R. RAMSAY WRIGHT, M.A., B.Sc., 
Professor in University College, Toronto, 
In the American Naturalist for December, 1882, E announced the 
discovery of this Demodex in pieces of pork-skin submitted to me 
by Mr. R. Awde, Inspector of Food for the City of Toronto. The 
portion of skin was thickly studded with white tubercles, varying in 
size from a pin’s head to a pea; these did not project much above 
the surface of the epidermis, but on reflecting the skin the larger ones 
were seen to extend into the subcutaneous tissue. The tubercles are 
enlarged sebaceous glands filled with hundreds of mites in various 
stages of development. The parts of the body chiefly affected are 
the mouth, cheeks, flanks, belly, and inner surfaces of the legs. 
Mr. Awde asserts that one in twenty of the pigs sent in to market 
in Toronto during the pork season, are affected to a greater or less 
extent with this cutaneous parasite. In view of such frequency it 
is somewhat singular that its occurrence has not hitherto! been 
recorded elsewhere, except by Dr. J. Csokor, of the Veterinary 
Institute at Vienna, Austria, who found in 1879, a herd of swine 
from Galicia affected in this manner, and described the Demodex 
causing the disease as a new variety, ). phylloides. 
The skin in these swine was, huwever, much more seriously 
affected, the collections of mites in the glands having caused the 
formation of subcutaneous abscesses frequently as large as a hazel- 
nut, which in one or two cases had become confluent on the inner 
surfaces of the legs. Mr. Awde has never observed any such cutane- 
1 After publishing the note in the American Naturalist, I learned that Dr. A. J. Johnson, of 
this city, to whom Mr. Awde had submitted specimens of affected skin, had sometime ago 
recognized thé parasite as a Demodex, and mentioned the fact of its occurrence at the meeting 
of the American Microscopical Society, 1881, 
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