CUTANEOUS AFFECTIONS OF PARASITIC OBIGIN. 405 



Pilaria. Siedamgrotzky, Rivolta, and Griffith have seen pus- 

 tular eruptions of the skin which were caused by thread-worms. 

 The former saw upon the external surface of the legs red-bordered 

 pustules which contained one or two round worms, which were 

 0.04 to 0.7 mm. long, and had awl-shaped tails. The parasites 

 had probably entered the skin through the hair-follicles, and some 

 were found measuring 1 mm. in length in the straw of the dog's 

 kennel. 



The treatment is simply cleanliness. 



Cutaneous Affections which are Caused by Vegetable 



Parasites. 



We know at present of but two skin diseases in the dog which 

 are ascribed to the presence of vegetable parasites; these are favus 

 and herpes, which belong to the fungi class, and may be simple or 

 ramified, membranous or non-membranous, double contourated, 

 cellular threads (hyphen), which become mixed in their growth 

 and form a real fungous bed or fungous turf (mycelium). These 

 fungous growths produce at their ends and at the point of their short 

 side branches bead- or string-like spores, uniting and ligating each 

 other, which are considered as sexual or multiplying organs (Fig. 



Favus spores, magnified 450 times, (von DOben.) 



93). We cannot make a strong distinction between the fungi of 

 favus and those of herpes, but there is a difference, as is seen in 

 the disease in its local form, and we have given a description of both. 

 1. Pavus. This fungus is called achorion Schonleinii, and is 

 developed upon the skin, between the epidermic layers in the 

 hair-follicles, and also in the hair itself. It may be transmitted 

 to the cat, horse, rabbit, mouse, and human beings, causing a 

 characteristic skin affection. 



