CHAPTER XLIII. 



DISEASES OP THE SKIN — continued, 



SCABIES different' VARIETIES OF ACARI SARCOPTES DpRMATO- 



DECTES — SYMBIOTES CXASSrFICATIO:^ — EXPERIMENTS OF HBRINO, 



HERTWIG, AND OTHERS AS TO TUB TRANSMISSIBILITT OF THE 



MITES TO MAN MANGE IN THE HORSE AND OX — SCAB IN SHEEP 



MANGE IN THE DOG AND CAT — TREATMEKT OF MANGE — 



DISEASES DUB TO EPIZOA POULTRY LOUSINESS FLEAS TICKS 



— BOTS MAGGOTS. 



PARASinO DISEASES OF THE SKIX 



This order of skin diseases may "be considered under two 

 Leads :— {1.) Diseases due to the presence of parasites from the 

 animal kingdom (dermatozoa) ; and (2.) those due to parasites 

 from the vegetable kingdom (dermatopbyta). 



L DISEASES DUE TO ANIMAi PAKASITES. 



SCAJJIES. 



Scahies, mange, itoh, or scab, is a contagious skin disPAse, 

 due to the presence of animal parasites belonging to the class 

 arachnida, the order acarida, or mites ; sub-order, crawling 

 mites; family, sarcoptes, of which there are, according to-^erlach, 

 three genera : — a, sarcoptes, that buiTow in the skin; h, dermato- 

 Uootes, that simply bite and hold on to the skin; and c, symbiotes, 

 living together in large numbers, and piercing no farther than 

 the epidermis in search of food. 



AU these paroaitcs live on serosity, the effusion of wliich is 

 caused by the irritotion wiiich they excite. 



