142 PAKASITIC SKIN DISEASES. 



were respectively jDut. It can be communicated from horse to 

 man, and vice ve?-sd ; though not with anything like the same 

 facility as from horse to horse. It is much less severe in horses than 

 in human beings. The parasites, away from their hosts, as when 

 they have got into the panel of a saddle, will retain their vitality for 

 a long time, certainly over six months, under favourable conditions. 



SYMPTOMS. — Tinea tonsurans derives its name from the shaven 

 aj^pearance presented by the attacked portions of skin. It spreads 

 by more or less circular patches which have a well-defined border, 

 and which, commencing, say, with a diameter of from half an inch 

 to an inch, do not usually exceed that of two inches. The affected 

 patch of skin becomes bald (as if shaven) by the hairs breaking off 

 close to the skin. The denuded surface as a rule presents but little 

 signs of irritation beyond the fact of small scarf-skin scales being 

 found on it. The elevated and inflamed condition of the border 

 of the invaded patch of skin seen in cases of ringworm in man, is 

 absent, or nearly so, in the horse. There is little or no itchiness. 

 When this fungous growth has attained its full extent, w4iich I have 

 ventured to put down as a general rule, at two inches, it seems to 

 die, and the hairs grow again as before, except that, for some time, 

 their colour is darker, and they are drier and more erect than usual. 

 Ringworm spreads from sej^arate centres, which become infected 

 usually, by the seeds of the disease being carried from one or more 

 previously diseased spots in the same animal, and which may run 

 into each other. It is found on various j^arts of the body (Fig. 46). 



TREATMENT.— After washing the affected parts well in the 

 manner described on page 139, we may ai:)ply either (1) or (7) 

 recommended on page 140 for mange, once or twice a day as 

 the case may demand. I have used 1 part of salicylic acid mixed 

 with 6 parts of lard with invariable success, and without irritating 

 the skin. I have had cases of ringworm which got well merely by 

 good grooming. In South Africa, biniodide of mercury ointment 

 (1 drachm to 4 oz. of vaseline or prepared lard) has always given 

 good results. In human practice, 1 part of thymol to 18 parts 

 of paraffin oil is an excellent application. A saturated solution 

 of common salt is generally efficacious. The destruction of the 

 parasite will be shown by the hair growing on the previously de- 

 nuded spots. Constitutional treatment, by tonics and special 

 articles of food, appears to have no influence on the removal of the 

 parasite, which is the only treatment required. 



DISINFBCriON (p. 141) should be applied to the grooming 

 utensils, saddlery and harness, the lining of which, in such instances 

 of infection, will generally harbour the parasite. 



