THE GENUS DEMODEX. 7 



sparse in places, and there are peculiar bare-looking spots (rather like 

 the marks made by the bites of horse-lice) occurring chiefly where the 

 hair is short ; the hair on these spots is very thin, but not entirely 

 absent. This disease usually commences on the saddle or neck of the 

 animal. It does not appear to be at all infectious. Linzell states that 

 he has failed to infect clean horses by placing scrapings swarming 

 with the mites on their skin, or even by rubbing it in. Nor does the 

 infection seem to be spread by the rugs or other equipment. The 

 Bemodex of the horse is often found in skin complaints due to other 

 causes, especially in Sarcoptic mange. 



The following instructions for dealing with Demodectic mange in 

 horses are .adapted from Linzell's notes : — The infected animal should 

 be thoroughly cleansed by washing or Eau de Javelle mixture, well 

 sweated, and then massaged with a cresylated Soap-oil mixture, which 

 should be washed off at the end of 24 hours, repeating the process in 

 from 4 days to a week. Exercise should be given during this treatment. 



The above account of the Demodectic mange of the horse and its 

 treatment is taken from notes kindly supplied me by Lieut. Leslie 

 Linzell, of the Royal Army Veterinary Service. In other cases (Schenzle 

 and Bidault's observations) there are small irregular ill-defined hairless 

 patches, more or less circular in shape, which spread, becoming confluent. 

 They are situated on the head (on the forehead, round the eyes, 

 parotids, etc.), afterwards spreading to the entire surface of the head, on 

 lo the chest and shoulders, etc. The skin near these patches is dry, 

 supple, elastic, and covered with thin scales forming little crusts. The 

 disease may also occur in a pustular form. 



Demodectic mange of the horse shows a tendency to spread over the 

 surface of the body if not treated. 



According to a record compiled by Colonel W. Pallin (as quoted by 

 Major E. J. Wadley), Bemodex was found in 4'52 per cent, in a large 

 number of scrapings taken from Army horses suffering from contagious 

 skin-disease (mange, etc.), or in contact with the same. 



Bemodectic mange of Cattle exists in the Shire Highlands of Nyasa- 

 land, where it also aflfects sheep, pigs, dogs, and cats. In cattle the 

 infected animal first shows a localised nodular eruption, usually on the 

 neck or shoulders. Later the nodules appear in greater numbers, 

 gradually spreading to the ears, face, trunk and upper parts of the 

 limbs. In neglected cases the nodules may coalesce and break, 

 discharging the purulent contents, and the irritation causes the skin 

 to become harsh, thickened, and denuded of hair. The nodules vary 



