5i6 Journal of Agriculture. [ioSept., 1908. 



skin, Chat would be better named prurigo, meaning ' to itch.' The term 

 mange is applied to another disease in horses and dogs, caused by acari, 

 to which it bears a closer resemblance. 



" This prurigo is characterised by an eruption of small scattered itch- 

 ing nodules, loss of hair from the withers, back, loins, and croup ; later 

 on the head, mane, and tail are also involved. Lt is of a contagious nature 

 and its progress depends very much on the surroundings and susceptibility 

 of the animal exposed to attack. In some places not one horse escapes, in 

 others the disease spreads slowly and a large percentage enjoys immunity, 

 two horses may work together, one suffers and the other escapes ; one attack 

 does not prevent a recurrence of the disease. This disease is not caused bv 

 the Jiorse mite {Acari fsoroptes), but is apparently due to the presence of 

 a vegetoid parasite of a microscopic fongi order which finds proper 

 nourishment on the skin, and bv rapid spore formation and growth, pene- 

 trates the hair follicles and perspiratory ducts. Being a foreign material, 

 it sets up irritation in the periphery nerves, interrupting and perverting the 

 functions of the skin, exciting itching and inflammation, with an extra- 

 ordinary accumulation of scurf and effete products." 



After recording his observance of an allied skin affection in cattle IMr. 

 Stanley proceeds •. 



" The symptoms are, first, a rash extending along, the neck, withers, 

 and back, to the tail, for about 18 in. on each side of the spine (not unlike 

 mosquito bites). The spots are the size of a threej>enny-piece, the hair is 

 slightly raised, and the little swellings can be felt by passing the hand 

 carefully over the parts. A day or two later, on the centre of some of these 

 a little pimple is felt and a small scab, with five or six hairs adhering, is 

 readily detached. The horse likes rrLanipulation and moves his lips sympa- 

 thetically. The itching is seen by a sore or two as large as a shilling on the 

 back, where the horse has rubbed the skin with his teeth. Soon the hair 

 stands erect on the withers and top of the spine, the skin begins to wrinkle, 

 it is thickened bv interstitial effusion. A large amount of scarf and loose 

 hairs accumulates and the sores (caused by rubbing and biting each other) 

 extend, vesicles form and break and their .secretions make horny scales, 

 which accumulate with the cuticular debris. The hair of the mane and 

 tail is destroyed by rubbing, the skin of both thickens and corrugates ; the 

 hair soon falls in quantities from the wither and back, in consequence of the 

 animal rolling, and in a week or two after the attack the parts are more 

 or less hare of hair, and covered with a thick scaly scurf, with patchy sores, 

 coated with exudation, blood, and dirt. 



" The progress and termination of this disease are variable. Some 

 entirely recover without treatment ; change of feed, such as stabling; grass 

 horses, has a good effect ; change of season, fxom warm moist summer 

 weather to cold dry winter, appears sufficient to check the development of 

 the parasitic fungus; it disappears in the winter months, and may, or may 

 not, reappear on the same horse the following year. 



" In its early stages and milder forms it is arrested by various applica- 

 tions, but when allowed to become chronic, intense pathological changes 

 proceed ; sore ears, ulcerations, and serious abscesses beneath the skin re- 

 duce the animal's condition, and make him unserviceable. The disease 

 is not of itself fatal, but deaths have resulted from the injudicious use of 

 irritating poisonous applications. 



" To distinguish this disease from others is not easy, as it bears a 

 remarkable resemblance to the itch, or horse mange; it differs, however, 



