532 VETEEINAEY HYGIENE 



must be saved by clipping, which, apart from its other 

 advantages, enables the animal's skin to be kept clean with 

 a minimum of trouble. 



Though a dirty skin is rightly held as an important 

 factor in the production of disease, it is well to bear in mind 

 that two parts of the body which are seldom clean, even in 

 a well-kept stable, viz., the mane and tail, are never 

 attacked by the disease. The hair from both these parts may 

 be rubbed away by the diseased animal scratching itself, 

 but neither are affected by mange. To remove the hair 

 of the tail from a mange case is a grave misapprehension. 

 It would appear in fact that the mange acarus of equines 

 avoids those parts of the body where only permanent hair 

 is found. 



Debility and neglect are the predisposing factors of the 

 disease, they are not the cause of it. Where the actual 

 cause comes from in all cases it is difficult to say, but we 

 are convinced that some horses store up on their skin the 

 eggs of the acari, and from time to time break out. With- 

 out this explanation it is difficult to account for recurrent 

 cases of mange in animals, apparently perfectly cured each 

 time, and not in the meanwhile exposed to reinfection. 



Such cases, of course, are in the minority, and are only 

 mentioned here as illustrating a point in infection. By far 

 the majority of cases are only attacked once, and no return 

 of the disease need be apprehended unless exposed to fresh 

 contagion. In the same way the majority of outbreaks can 

 be traced to infection from a previous case, either direct or 

 indirect through the medium of blankets, saddle, harness, 

 grooming gear, bedding, or other ways. 



When psoroptic mange breaks out in a body of horses 

 half measures are no use, systematic and radical methods 

 must be adopted. It will probably be found to occur 

 during the winter months, and such measures as the 

 abolition of bedding and blankets may be objected to, but 

 it is an absolutely necessary measure. 



The first thing is to examine every animal, and adopt 



the group system of affected, doubtful, free from disease. 

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