DISEASES OF THK SKIN. 479 



scrapings on black cardboard and Nvarniing, or better by macerating 

 scabs or scrapings in a solution of caustic soda or potash and then 

 exaniing them microscopically. Like other acari, tiiis is wonder- 

 fully piolilic, a new generation of fifteien individuals being possi- 

 ble every fifteen days, so that in throe ujonths the otfspring of u 

 single pair may produce generations aggregating 1,.')()0,000 young. 

 The jSarcoptes have less vitality than the nonburrowing acari, as 

 they die in an hour when ke[)t apart from the skin in dry air at a 

 heat of 145'^ F. They live 12 to 14 days apart from the skin in the 

 damj) air of a stable. On a piece of damp hide they lived till the 

 twenty- fourth day, when they began to die, and all were dead on the 

 twenty-eighth. 



Symptoms. — The symptoms are an incessant, intolerable, and in- 

 creasing itching of some part of the skin (head, mane, tail, back, 

 etc.), the horse inclining himself toward the hand that scratches 

 iiim, and moving his lips as if himself scratching. The hairs may be 

 broken and rubbed off, but the part is never entirely bald, as in ring- 

 worm, and there may l)e papules or any kind of eruption or open 

 sores from the energy of the scratching. Scabs of any thickness 

 may form, but the special features are the intense itching and tlie 

 jH-esence of the acarus. 



Treatment consists in the removal of the scabs by soapsuds, and, if 

 necessary, a brush and the thorough application of tobacco \\ ounces 

 ami water *2 pints, prepared by boiling. This may be applied more 

 than once, and should always be repeated after 1;") days, to destr<ty 

 the new brood that may have been hatched in the interval. All har- 

 ness and stable utensils should be similarly treated: blankets and 

 rubbei's may be boiled, and the stalls should be covered with a white- 

 wash of quicklime, containing one-fourth pound of chlorid of lime 

 to tlie gallon. 



^^'hen there are too many animals to treat by means of hand dre.ss- 

 ings, the lime-and-sulphur dip oi- the tobacco dip may be used and 

 aie very effective, though the cresol dips are fairly effective. These 

 dips may be j^urchased and made uj) in the dilution called for on the 

 container. The affected animals may be dipped wlicu the number 

 warrants it and facilities are available; othei'wis«' the; dips may Ite 

 applied with a swab or a spray pump. Directicms for constructing 

 a dipping vat may be obtained from the United States Depart- 

 ment of Agriculture on application. Any treatment used should 

 be lepeated in the course of 10 to 14 days. Tf the stables aic not 

 disinfected, animals should Ikj removed after treatment and put in 

 clean stables or on clean pasture for at least a in(»nth to allow the 

 mites in the infested stables to die. Otherwise the disease mav recur. 



