202 Veterinary Medicine. 



Suis already described. Finally the trombidium 6 legged larva 

 attacks the dog on paws, limbs, abdomen, nose and elsewhere 

 giving an appearance of mange which, however, shows in sum- 

 mer only and recovers in a day or two if the victim is shut 

 indoors. 



Symptoms. The common sarcoptic scabies habitually starts 

 about the head (muzzle, eyelids, ears) suggesting that it may 

 have been contracted by biting or smelling an infested animal. 

 The early implication of the paws, breast, abdomen, back and 

 rump is similarly suggestive." On parts .sparsely covered by hair, it 

 shows minute red points, soon enlarging to papules as large as 

 a lentil or pea, and at times crowned by a vesicle. This is at- 

 tended by insupportable itching, aggravated by a warm place or 

 covering, and manifested by restless movement, biting, scratching 

 and rubbing, and by movements of the hind foot and legs when 

 the parts are handled or gently rubbed. Under this constant 

 friction, redness, congestion and swelling spread over the skin be- 

 tween the papules, and the resulting abrasions, ruptured vesicles 

 and open ends of the burrows of the sarcoptes exude a serous 

 liquid which concretes as crusts and scabs, grayish yellow, brown, 

 red or of other tint. An attendant exudation into the skin and 

 subcutaneous tissues, produces thickening, rigidity, corrugation 

 and adhesion to the parts beneath. The exudate decomposing be- 

 comes very offensive. Pustules and other skin lesions are not 

 uncommon. The hair is generally shed, though unlike ringworm, 

 the bare patches still retain a few scattered hairs. The itching 

 does not diminish with the advance of the .skin lesions, but 

 scratching, rubbing, or, if too painful, licking is incessant. The 

 general health suffers, appetite is impaired, and under the con- 

 stant excitement day and night the subject becomes emaciated and 

 debilitated and may die exhausted in two or three months. 



Diagnosis depends mainly on the gradual and even rapid ex- 

 tension of the disease from the primary centre or centres over the 

 whole skin, on the intensity of the itching, on the extension from 

 one dog to others living with it, and above all on the demonstra- 

 tion of the acarus. This last is often difficult because of the bur- 

 rowing habits of the sarcoptes. The crusts should be raised and 

 examined on their deep aspect. Or the surface of the skin may 

 be scraped until the cuticle is removed and its deepest products 

 examined on a piece of black paper with a lens. If still they es- 



