451 



laterally and deeply in the skin and other tissnes, destroying them as 

 it advances (rodent nicer). It is made nj) of a fibrous framework and 

 numerous round, ovoid, or cylindrical cavities, lined with masses of 

 epithelial cells, which may be squeezed out as a fetid caseous material. 

 The most successful treatment is early and thorough removal with 

 the knife. 



VEGETABLE PARASITES OF THE SKIN. 



Parasite: Tricliophyf on tonsurans. Malady: Tinea tonsurans — 

 Cirvinate ringworm. — This is esx^ecially common in j-oung horses com- 

 ing into training and work, in low-conditioned colts in winter and 

 spring after confinement indoors and during moulting, in lymphatic 

 rather than nervous subjects, and at the same time in several animals 

 that have herded together. The disease is common to man, and 

 among the domestic animals to horse, ox, goat, dog, cat, and in rare 

 instances to sheep and swine. Hence it is common to find animals of 

 different species and tl\eir attendants suffering at once, the diseases 

 having been propagated from one to the other. 



In the horse the symptoms are the formation of a circular scruffy 

 patch where the fungus has established itself, the hairs of the affected 

 si)ot being erect, bristly, twisted, broken, or split iip and droi^xjing off. 

 Later the spot first affected has become entirely bald, and a circular 

 row of hairs around this are erect, bristlj', broken, and split. These 

 in turn are shed and a new row outside passes through the same proc- 

 ess, so that the extension is made in more or less circular outline. 

 The central bald spot, covered with a grayish scruff and surrounded 

 by a circle of broken and split hairs, is characteristic. If the scj'uff 

 and diseased hairs are treated with caustic potash solution and put 

 under the microscope the natural cells of the cuticle and hair Avill be 

 seen to have become transparent, while the groups of spherical cells 

 and branching filaments of the fungus vStand out prominently in the 

 substance of both, dark and unchanged. The eruption usually appears 

 on the back, loins, croup, chest, and head. It tends to spontaneous 

 recovery in a month or two, leaving for a time a dappled coat from 

 the spots of short, liglit-colored hair of the new growth. 



The most effective way of reaching the parasite in the hair follicles 

 is to extract the hairs individually, but in the horse the mere shaving 

 of the affected x^art is usually enough. It may then be x^ainted with 

 tincture of iodine t>vice a day for two weeks. Germs about the stable 

 may be covered up or destro^-ed by a whitewash of freshl}' burned 

 quicklime, the harness, brushes, etc., may be Avashed with caustic 

 soda, and then smeared with a solution of corrosive sublimate one-half 

 drachm and water 1 x^int. The clothing may be boiled and dried. 



Parasite: Trichophyton sporuloides. Malady: Plica Polonica. — 

 Ptica Polonica, vi-luch mats together the mane and tail of the horse 

 as well as the hair of men, is associated with numerous sx^ores of a 



