GEELACH ON THE ITCH AND MANGE. 



165 



Scabies of the horse has been considered by Gerlach 

 under three heads : Scabies equi sarcoptica, Scabies equi 

 dermatodectica, and Scabies equi symbiotica. 



The insect met with in the first form had not been de- 

 scribed before ; Gerlach drew attention to it, and stated that 

 he had found it in two-thirds of the cases of mange met 



Fig. 185. (GERLACH.) Sarcoptes equi. 



with in the practice of the Berlin Veterinary School. The 

 fact of this insect not having been known until Gerlach 

 has furnished us with its peculiarities and history, is ex- 

 plained from the difficulty experienced in finding it, and 

 not from its rarity. In the arrangement and character of 

 portions of the body, this acarns is very like sarcoptes 



