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be seen small nodules or vesicles, whicli change into scab ; the skin 

 then becomes thickened, wrinkled, and drawn into folds, which gives 

 it the appearance of a rhinoceros hide. 



The affected parts become itchy, especially when the animal feels 

 the heat and in trying to relieve this itching by rubbing or biting the 

 sore parts, raw places very soon appear on the skin, and the inflamma- 

 tion becomes general. At this stage mange is very easily recognised, 

 but at the very start of the disease and when there are only a few 

 hairless spots, it is not readily detected. 



All doubt can, however, be removed when the itching begins ; the 

 Sarcoptes are then sure to be present. 



All horses suffering from mange are very fond of being scratched, 

 and show their appreciation of such an act by moving their lips. 



From these notes it is evident that if neglected, mange caused by 

 Sarcoptes, easily becomes an obstinate disease, since the Acarinae, be- 

 ing so deep in the skin, are not always easy to reach. Thus the sooner 

 treatment is started the better will be the chance of success. 



This disease may be transmitted to human beings. 



Dermatocoptes Mange. 



This parasite differs from the Sarcoptes, in that it lives on the sur- 

 face of the skin, and derives its nourishment from the blood and 

 lymph. 



It generally begins by attacking the base of the mane, the tail, the 

 throat, or the sheath, udder, and the soft parts in the inside of the 

 legs. This kind of mange does not, as a rule, spread over a large 

 surface, but remains on circumscribed spots. 



The bite of the Dermatocoptes causes a local irritation, producing a 

 nodule, out of which oozes a sticky liquid, which in drying forms a 

 scab ; at the same time a desquamation (forming scales) of the skin 

 and a falling out of the hair takes place, producing a well-defined spot 

 whereby the disease can be located. 



These scales and scabs remain and stick together, forming a bark- 

 like surface under which the skin is thickened, assuming the appear- 

 ance of tanned leather. The irritation thus caused induces the animal 

 to rub itself whenever it can, and very soon the skin becomes very 

 much inflamed and breaks into sores. 



Whenever the Sarcoptes or Dermatocoptes mange spreads over the 

 body, it will become very difficult to recognise the one from the other. 

 It is only as long as the different forms keep to the seat of their pre- 

 dilection that it is possible to diagnose whether the disease is caused 

 by Sarcoptes or by Dermatocoptes. 



It is evident from the superficial seat of the Dermatocoptes that 

 this parasite is much easier to destroy than the deeper seated Sar- 

 coptes. 



Dermatophagus Mange. 



This parasite is mostly observed on a horse's legs usually about the 

 fetlock, where the symptoms are very much the same as what has 

 been described as being caused on the body by the other two Acarinae. 



This form of the mange very seldom reaches the body, and general- 

 ly remains on the limbs, sometimes reaching the elbow joint on the 

 forelegs or the hock on the hind legs. 



