718 DISEASES OF THE SKIN. 



Many preparations are recommended by physicians, sncli as 

 a solution of sulphate of copper, or of the nitrate of silver in 

 the proportions of seven grains to ten ounces of water ; unguen- 

 tum picis ; an ointment of the cocculus indicus, 3i. to 3ii. ; 

 adipis, |i. ; nitrate of merctiry ointment, a solution of nitrous 

 acid, sulphureous acid, and a variety of other remedies. The 

 application of the stick nitrate of silver round the patches is 

 another favourite method of treatment, and when all these fail, 

 the hairs are removed singly with a pair of forceps (depilation.) 



TINEA TONSUEANS. 



Piing-worm is a common skin disease in the lower animals, and, 

 unlike favus, is not confined to those ill cared for, but is un- 

 equally seen amongst carriage -horses, hunters, and w^ell-groomed 

 cattle, and is defined to be an affection implicating the hairs of 

 the skin, usually assuming a circular form. The hairs, becoming 

 dry and brittle, have a tendency to crack or break across and 

 fall off, leaving isolated patches of baldness, constituting w^hat is 

 termed alopecia circumscripta. This condition is more particularly 

 met with in the dog ; generally, however, an erythematous erup- 

 tion, accompanied by slight swelling of the skin and some 

 itchiness, manifests itself, and a fungus ultimately appears, which 

 had been developing between the true sldn and epidermis. This 

 fungus has a wliitish appearance, and a powdery or fine bran-like 

 aspect. It covers the epidermis between the hairs, and forms 

 around them a complete whitish sheath. The hairs break un- 

 evenly, become ragged at their ends, and have the appearance of 

 having been eaten through ; at the same time their broken 

 stumps are much altered, bent, and twisted, and are lighter in 

 colour than the healthy hair. 



M. Bazin states that the parasite may destroy the hair-bulb 

 and the capsule of the hair follicle, give rise to the formation of 

 pus, and cause perfect baldness of the part. — (Anderson, Bazin, 

 HiLLiER, Aitken.) This form of ring- worm differs from the vesi- 

 cular form (lierpes circinatus) by the absence of vesicles, and by 

 the formation of scurf or scales around single hairs, or in patches 

 surrounding several hairs. Again, if a hair in the vesicular form 

 be pulled gently, the probability is that it wiU come up by the 

 root, as in the case of a healthy hair, but in this form it will break 

 off near the skin, or within its follicle. 



