552 



DISEASES OF THE SKIK 



which are covered with wool ; with time it invades the whole sur- 

 face of the body, except the head. 



3. Symbiotic mange affects only certain regions : the extremities 

 of the legs in the horse and sheep (pastern mange), the base of the 

 tail in the ox (tail mange), the auricular concha in the dog, the 

 rabbit, and the cat (ear mange). In the different domestic species 

 we may find the following acari : 



A. In the horse : Sarcoptes scabiei, Psoroptes communis, Sym- 

 biotes equi. Sarcoptic mange is the most important. 



B. In the ox : Psoroptes communis, Symbiotes bovis. Psoroptio 

 mange is the most serious. 



C. In the SHEEP : Sarcoptes squami/erus, Psoroptes communis,. 

 Symbiotes avis. Psoroptic mange is the principal. 



D. In the goat : Sarcoptes squamiferus. 



E. In the dog : Sarcoptes squamiferus, Symbiotes canis. Sar- 

 coptic mange is the most important. 



F. In the cat : Sarcoptes minor, Symbiotes felis. Sarcoptio 

 mange is the principal. 



G. In the pig : Sarcoptes squamiferus. 



H. In the rabbit : Psoroptes and Symbiotes cuniculi. 

 Concerning the transmissibility of the different manges to ani- 

 mals and man we possess to-day precise facts : 



I. All sarcoptes may live for an indefinite period upon man's 

 skin, but the psoroptes and symbiotes die very rapidly ; they occa- 

 sion but slight irritations. 



2. The horse may contract sarcoptic mange of the sheep, pig, 

 dog, and cat. 



3. The ox takes the sarcoptes of the horse, sheep, goat, and cat. 



4. The sheep contracts sarcoptic mange of the goat. 



5. The dog takes the sarcoptes of man, pig, cat, sheep, and 

 goat. 



6. The pig contracts sarcoptic mange of the goat. 



From this summary we see that sarcoptic mange is especially 

 transmissible from one species to the other. 



Symptoms of mange in general. Mange is never developed 

 but by contagion. The incubating period — that is to say, the 

 interval which elapses between the moment when the acari are 

 deposited upon the surface of the body and the appearance of 

 cutaneous alterations — varies according to the number of trans- 

 mitted parasites. When in small numbers the first manifestations 



