Sarcoptic Acariasis in Solipeds. 163 



loss, breakage and twisting of hair, by the marked abrasions and 

 sores, and by the intense, encreasing pruritus, but also by marked 

 loss of condition, which may go on to marasmus and death. 



The most satisfactory symptom is the discovery of the acarus. 

 By exposing the patient to the warm rays of the sun, or placing 

 him in a hot room, the sarcoptes is tempted to leave its burrow, 

 and climb on the crusts and hairs, where its presence can be de- 

 tected by the aid of a lens. Or the crusts are detached from the 

 skin and their deep surface examined when the parasite may be 

 found in the midst of the epithelial debris. If the examination 

 is made in a warm room under a low power, the movements in 

 the scales caused by the active acari will help materially in their 

 discovery. Should they still escape observation, the cru.st may 

 be bound on the skin of the human arm, when, in a few minutes, 

 a pricking sensation is felt, and in twelve hours on the removal 

 of the crust, the parasite is detected as a white point in the 

 centre of a pale red papule. 



Diagnosis. It is important to distinguish this acariasis from 

 constitutional pruritus with papules, and moist eczema. 

 These are likely to be more generally diffused over the body and 

 the papules are likely to be more isolated, and the crusts are 

 confined to the papules or vesicles. They also require constitu- 

 tional treatment and are little or not at all affected by local dress- 

 ings, whereas sarcoptic mange is quickly responsive to local treat- 

 ment, and is unaffected by internal medication. The presence of 

 the sarcoptes is even more conclusive. 



The diagnosis from other forms of acariasis is less easy. 

 Dermanyssus Acariasis is usually betrayed by the proximity 

 of the horses stall to filthy hen roosts, and accumulations of hen 

 manure swarming with large grayish acari, which may also be 

 found on the horse's skin especially at night. The depilations 

 are on any part of the skin, as small isolated spots which do not 

 tend to become confluent, whereas in sarcoptic acariasis they 

 rapidly run together forming extensive patches. Psoroptic 

 acariasis usually begins at the nape of the neck, extending along 

 the mane, and at the root of the tail, and often confines itself 

 largely to these points, causing much tumefaction and wrinkling of 

 the skin, with free liquid exudate and abundant crusts. Sarcoptic 

 mange extends more rapidly and generally. The psoroptes is 

 easily known by its more oval form, longer limbs and long ros- 



