276 ON DEMODEX PHYLLOIDES. 



ous abscesses. As the parasite is confined to the skin, and .does not 

 appear to affect the general health of the animal, he has merely 

 ordered the removal of the skin from the parts involved, a precaution 

 which is entirely sufficient to render the flesh useful for food. 



My observations have served to establish the complete agreement 

 of my specimens with those of Csokor. I have accordingly concluded 

 that a synopsis of his paper, which is probably accessible only to a 

 few of those who may be interested in the matter, with a copy of his 

 excellent figures, may stimulate enquiry into the distribution of this 

 parasite in America, and perhaps into the means best adapted to 

 hinder its attacks becoming so formidable as represented by Dr. 

 Csokor. 



Dr. Csokor's paper considers : 



1. The history of hair-sac mites in general. 



2. Their systematic position. 



3. The natural history of D. phylloides in particular. 



4. Its occurrence and mode of life. 



1. — Species op Demodex occur in the sebaceous glands and hair 

 follicles beside the nose in man, occasion forms of mange in dogs 

 and cats, and have been recorded (but merely in isolated cases) from 

 the sheep, horse, ox, and Surinam bat. The best known forms have 

 been distinguished by Megnin as three varieties : 



D. folliculorum hominis. 

 D. folliculorum canis. 

 D. folliculorum cati. 



A good many experiments have been made with a view to ascer- 

 tain whether the Demodex of the dog is capable of being transferred 

 to man, and vice versa, and although some results appear to render 

 likely the possibility of both methods of transference taking place, 

 yet the weight of evidence unquestionably points the other way. 



The mode of occurrence of the Demodex of the dog is so totally 

 unlike that of the Demodex of man, that apai't from difference in 

 form and size, we would be inclined to suspect a difference of at any 

 rate varietal value. In man the Demodex is found on the hairless 

 parts of the face and is perfectly harmless, in the dog it is found in 

 the hairiest parts and brings about a troublesome and often fatal 

 cutaneous disease. Experiments, however, as to transference can 

 hardly be depended upon, for although it is quite certain that the 



