DISEASES OF THE SKIN. 479 
scrapings on black cardboard and warming, or better by macerating 
scabs or scrapings in a solution of caustic soda or potash and then 
examing them microscopically. Like other acari, this is wonder- 
fully prolific, a new generation of fifteen individuals being possi- 
ble every fifteen days, so that in three months the offspring of a 
single pair may produce generations aggregating 1,500,000 young. 
The Sarcoptes have less vitality than the nonburrowing acari, as 
they die in an hour when kept 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 
damp 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 
him, 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 be 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 the 
presence of the acarus. , 
Treatment consists in the removal of the scabs by soapsuds, and, if 
necessary, a brush and the thorough application of tobacco 13 ounces 
and water 2 pints, prepared by boiling. This may be applied more 
than once, and should always be repeated after 15 days, to destroy 
the new brood that may have been hatched in the interval. All har- 
ness and stable utensils should be similarly treated; blankets and 
rubbers may be boiled, and the stalls should be covered with a white- 
wash of quicklime, containing one-fourth pound of chlorid of lime 
to the gallon. 
When there are too many animals to treat by means of hand dress- 
ings, the lime-and-sulphur dip or the tobacco dip may be used and 
are very effective, though the cresol dips are fairly effective. These 
dips may be purchased and made up in the dilution called for on the 
container. The affected animals ‘may be dipped when the number 
warrants it and facilities are available; otherwise the dips may be 
applied with a swab or a spray pump. Directions for constructing 
a dipping vat may be obtained from the United States Depart- 
ment of Agriculture on application. Any treatment used should 
be repeated in the course of 10 to 14 days. If the stables are not 
disinfected, animals should: be removed after treatment and put in 
clean stables or on clean pasture for at least a month to allow the 
mites in the infested stables to die. Otherwise the disease may recur. 
