718 DISEASES OF THE SKIN. 



" The symptoms of the disease are seldom seen in the first 

 stages ; they consist merely of circumscribed spots from which the 

 hair falls, and upon which are noticeable a few small pimples. 

 These patches extend rapidly, and fresh ones appear on other 

 parts. Any portion of the skin may be affected, but the head, 

 legs, belly, and sides are usually the seat of the disease. The 

 affected places are almost hairless, and what hair remains is 

 easily pulled out ; small pimples and pustules stud the surface, 

 the latter varying in size from a pin's head to that of a pea. The 

 confluence of the pustules, and the discharge of their contents* 

 give rise to scabs ; these crack and bleed, and so produce a most 

 repulsive appearance. In white-haired dogs, the skin is red ; in 

 all it is extremely hot, and emits an unpleasant odour. The 

 irritation does not excite much scratching, but the dog frequently 

 shakes himself. More pain than itching seems to accompany 

 the disease. In cases where the whole body is affected, loss of 

 condition is most marked ; and in cold weather the almost total 

 loss of hair may cause death, if the animal be not kept in a warm 

 place. This stage, too, is always accompanied by a ravenous 

 appetite, due, probably, to the rapid loss of animal heat. 



" Diagnosis. — In white dogs the colour of the skin may cause 

 the disease to be mistaken for ' red mange,' or ' eczema.' 

 The circumscribed spots in the first stages may be confounded 

 with some forms of tinea ; and the loss of hair and presence of 

 scabs seen in the fully developed disease may easily be mistaken 

 for ordinary scabies. The pustules, the heat of the skin, and 

 the comparatively slight itchiness shown, are, however, nearly 

 diagnostic. Positive diagnosis can only be made by the aid of 

 the microscope and the detection of the parasite. If we puncture 

 one of the pustules, and mix its contents on a slide with a little 

 water, the acari are easily discovered. I have found as many as 

 thirty in one pustule. Sometimes we may detect them on the 

 root of a hair removed from an affected spot. 



" The disease is contagious, but not to such an extent as 

 scabies. My own dog had been in daily contact with an affected 

 one for a fortnight, and showed no signs of the malady. In- 

 oculation of one or two dogs has been unsuccessful, but that it 

 is contagious is beyond doubt. I know a kennel in which this 

 disease appeared about three months after an infected dog had 

 been allowed to live with the others for a week or two. The 



