fOG 



DISEASES OF THE SKIN. 



hy laying tlie latter on a paper in the sun, where next day they 

 are found in small clusters." — (Gamgee.) 



Fig, 130. — Symbiotes equi.— (Gerlach. 



According to Mr. Gamgee, who is translating from Gerlach, 

 the finding of the various mites which constitute so essential a 

 feature in mange, " has as yet been attended with great diffi- 

 culty," and the various procedures for their detection are as 

 follows : — 



(1.) " Animals placed in the sun, and carefully examined ; 

 the acari (sarcoptes) do not get on the surface of the epidermic 

 scales and on the hairs, as dermatodectes do ; and these can be 

 seen with the naked eye. 



(2.) " The sarcoptes are found below the scales or scabs, 

 which may be so adherent to the skin that, on being removed, 

 the latter may bleed. The dermatodectes are observed, after 

 the animals have been exposed to the sun, on the outer part 

 of these scales ; but the sarcoptes are only seen on the inner. 

 The scales examined should always be fresh, and they may be 

 laid on black paper in a warm place in the sun, and then 

 examined by a weak lens embracing a wide field of view. The 

 small sarcoptes are only discovered when the cuticle has been 

 removed with the scab. 



(3.) " The sarcoptes are most certainly and easily found 

 when the scales are laid with their under surface uppermost 

 on the arm. In the course of twelve hours they pass from the 



