Symbiotic Acariasis in Cattle. 175 



Around the margins of the affected part may be found small 

 miliary vesicles, which burst and dry up forming an encrustation 

 of encreasing thickness. As the result of the constant rubbing, 

 licking, etc., larger sores of all kinds may be developed. The 

 psoroptes may be found in large numbers beneath the crusts, 

 and may be detected with the naked eye or better with a lens, 

 when the crusts are placed on a sheet of black paper. 



The disease is favored by the housing in close foul stables in 

 winter, and the parasite is driven downward by the cold to attack 

 the skin and cause greater irritation. When the stock is turned 

 to pasture in spring the irritation often ceases in a great measure, 

 the freer secretions supplying the wants of the parasite so that it 

 does not care to bite. There remain, however, bare spots on the 

 neck, rump and elsewhere, and when once more turned into winter 

 quarters, the apparent recoverj' is succeeded by a new and wider 

 extension. 



The treatment of psoroptic scabies in cattle does not differ ma- 

 terially from that of the horse. It is, however, important to avoid 

 preparations of mercury to which the bovine system is specially 

 susceptible, and which, taken in by licking with the barbed 

 tongue, or directly absorbed through the abraded skin is liable to 

 cause mercurialism and salivation. The other agents, tobacco, 

 tar, oil of tar, lysol, creolin, creosote, naphthalin, potassium sul- 

 phide, in their various preparations may be freely used after the 

 skin has been prepared by soaking with soap suds and thorough 

 brushing. Special irritation may be counteracted in the same 

 way, and debility by better hygiene and diet. 



Prevention demands the same general precautions, proprietary 

 and official, as in the case of the hc-r-se. 



SYMBIOTIC ACARIASIS IN CATTLE. 



The essential cause of this affection, the Symbiotes Scabei 

 var. Bovis, (Dermatophagus Bovis), does not differ in ap- 

 pearance from that of the horse. As in the case of the psoroptes 

 the distinction of the two varieties affecting horse and ox must be 

 made from the fact that the symbiotes taken from the ox does not 

 establish itself permanently on the horse, nor that of the horse on 



