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ANIMAL SIMPLES.

ITCH INSECT.The Itch insect is Acorus scabiei, and furnishes a toxicprinciple— Psoricum. The loathsome itch outbreak onthe skin (incurred, as is generally supposed, throughdirt and uncleanly habits), is characterized by manypimplea containing at first a thin watery fluid, and thenbecoming pustular. At the base of each may be some-times found by exploration with a needle, the Itchinsect, or Acarus, which causes by its presence theirritation and itcliing known as the leading Symptomsof this disgusting affection. So contagious, however,is the itch that it may be occasionally taken evenby anyone who is scrupulously clean and particular.The stränge fact obtains that in some cases, if theeruption of itch is repressed or throvvn in, an epileptieseizure will ensue ; Observation of which has led to thegiving Psoricum, or the Itch insect dement, medicinallyas a eure for the falling sickness.

This psoricum is prepared by collecting the clear fluidfrom thirty of the pimples opened at the bottom, whilstat the same time scraping out the insect, if it caii bediscerned, from each pimple. The quantity of liquidthus procured constitutes, with two hundred drops ofalcohol, a mother tineture of psoricum. Animals areliable to psoric epilepsy; and in order to treat eachkind, whether horses, sheep, goats, or dogs, the specialAcarus of its particular genus must be selected. ThisItch insect is not the only one which predisposes toepilepsy; for instance, the mite (Acarus ciro) in flour,with which caged nightingales have been fed, gave themepileptie fits, always terminating fatally. Psoricum fortreating epilepsy may be likewise prepared from thisinsect by taking some of the flour containing the acarus,to the nnmber thereof of about two hundred, macerating