MANGE. 375 



srarf-skin. Tlio arari wliidi avo ilio active ap;onts in tlic prndiirtion of 

 this diseaso, are of two kinds, called respectively, tlie Sareoiites and Der- 

 nmdectes einii. Tlu- latter parasite is the more eoninion ; l»ut, as the 

 ravatres caused by l)oth are similar, fmtlier description is unnecessary. 

 The insects are so small, that they cannot l)e seen by the naked eye, hut 

 they may he discovered In' the aid of the microscope or even of the 

 pocket lens. The attacks of these animalculL cause irritation and it( hin^^ 

 of the skin; and, as a result, the hair falls off in patches. 



It is important to bear in mind, tirst, that Mang'e is not primarily a 

 skin disea.se, l)ut the result of insects being allowed to lodire in the skin ; 

 and, secondly, that the skin, either from want of <^roominfr, or from 

 ])0verty of the blood or system, or from the effect of unsuitable food, or 

 from some or all of these causes, is f^enerally, and perhaps we mipjht 

 safely say, must be in an unhealthy state, before it is in a condition suit- 

 able for these parasites to live in and breed. 



Yountr horses taken up from grass, especially if poor, are sometimes 

 found to l)e affected with the mange insect, but more commonly with lice. 



769. Mange, a sure sign of neglect or mismanagement. 



Mange never occurs in healthy, well groomed, well fed horses. It is a 

 sure sign of neglect and dirt, or of injudicious feeding, or of bad manage- 

 ment of some sort. The owner will do well to change his servants, when- 

 ever this disease appears in his stable. 



770. Mange, not contagious among healthy, well groomed horses. 



Mange is not contagious among healthy and well groomed horses. It 

 is very 2")ossible, that some of the insects may find their v,'ay from a dis- 

 eased to a neighbouring healthy horse. But they will not remain, they 

 will not lodge permanently, still less ■will they breed, in a skin to which 

 the brush is well applied and in which they are in consequence disturbed 

 two or three times a day. 



Horses, however, in a debilitated or neglected state are veiy susceptible 

 to this disease, and among such it is very readily transmitted from one 

 to another. Hence, when circumstances, v.hich are more or less common 

 to all the animals in a stable or camp, engender this disease in one horse, 

 it is necessar}' that he should at once be separated from the others. The 

 brushes and clothing must also be kept separate. 



771. Signs of Mange. 



Mange usually commences at the roots of the hair of the mane and tail. 

 As stated above, it is caused by the presence of insects. Multitudes of 

 minute pustules appear, whose summits gradually expand into vesicles, 

 Avhich burst and coalesce with one another, and by their united discharges 

 form patches of encrustation upon the skin. At these patches the hair 

 loosens at its roots, and either falls out, or it rubbed oil from time to 

 time, and at length the place is left bare. The follicles of the hair 

 des(|uamate in the form of bran-like scales or meal dust. 



