938 Scabies. 



mangy animals should be used in tanneries only after thorough 

 disinfection and complete drying, the wool of mangy sheep 

 should be sold only in enclosed sacks. 



Literature. Brandl & Gmeiiier, W. f. Tk., 1900, 1.S7, 177, ,349, 489; 1901, 

 229. — <'habert, Traite <ie la gale et des dartres des animaiix, 1783. — Fiirstenberg, 

 Die Kratzmilbe d. Mensclien und d. Tiere, 1861. — Gerlach, Kratze u. Eaiide, 1857. — 

 Giinther, Pr. VI). 190;], 1, ,S7.— Gurlt & Hertwig, Yergl. Filters iib. d. Haut d. 

 Menschen u. iib. Kriitz. u. Eaudemilbe, 1S44. — Hertwig, Mag., 1845, 165. — 

 Joest, B. t. W., 1901, 56.— Johne, Birch-Hirsehfeld "s Allg. Path. Anat., 1889.— 

 Kaiser, A'ortr. f. Tzte., 1886, IV, H., 10. — Megniii, Les parasites et les maladies 

 parasitaires, 1880. — Bailliet, Zool. ined. 1895, 639. — Eobin, Memoires sur diverses 

 esperes d'Acarus, etc., 1869.— Verheyen, Diet., 1862, VII, 549.— Ziirn, Tierische 

 Parasiten, 1882, 3. 



(a) Scabies of the Horse. 



In the great majority of cases scab in the horse is caused 

 by the Sarcoptes scabiei, far less often by Dermatocoptes com- 

 munis (var. equi). Both forms of scab may spread widely over 

 the l)ody, while Dermatophagus communis (var. equi) is almost 

 exclusively parasitic on the skin of the extremities. 



1. Sarcoptic Mange. It begins as a rule on the head, on 

 the sides of the neck or on the shoulders, far less often in the 

 saddle region or on the outer surface of the thighs, but oc- 

 casionalh'' also on other parts of the body and extends from here 

 over a great part of the surface of the l)ody if the care of the 

 skin is neglected; the extremities, however, are attacked only 

 in very severe cases. As a first symptom intense itching ushers 

 in the course of the disease and causes the animals to gnaw or 

 rub the affected part of tlie body violently; if one scratches the 

 affected places the animal exhibits signs of pleasure by quiver- 

 ing or turning up the upper lip, by pressing against one and 

 so on. 



At first small nodules form on the skin, which may be felt by 

 stroking, and at these places whisps of hair are matted together 

 by loosened epidermis scales, the hair itself being easily pulled 

 out. From the nodules little vesicles develop later on and soon 

 thickish crusts with moist bases. In many cases desquamation 

 alone is noticed for a long time. With the extension of the 

 affection the scales increase, the hair falls out in larger patches 

 (Fig. 142), while in the neighborhood of the irregular Inild spots 

 on the skin, which are not sharply circumscribed and are still 

 covered with hair, minute nodules and scales may be found. 

 Later on the skin thickens and thick folds form on the movable 

 parts of the body, on the neck and about the throat; between 

 these the surface appears raw, bleeds easily and exudes a puru- 

 lent secretion. 



In neglected and protracted cases the whole body becomes 

 almost hairless and the diseased skin is covered all over with 

 scabs and crusts ; after these are removed a purulent layer be- 



