Phenyl-hydrazine is acted upon by aceto-acetic ether, when phenyl-monomethyl-pyrazolon, ethyl alcohol and water results.

Properties.—Colorless, odorless, scaly crystals, of a bitterish taste. Soluble in water, ether and chloroform.

Dose.—Horses and cattle, 3 to 4 drs.; sheep and pigs, ¹/₂ to 1 dr.; dogs, 5 to 20 grs.

Actions.—Powerful antipyretic, anodyne and local anesthetic, antiseptic, cardiac depressant; it reduces temperature very quickly, usually within half an hour and the effects continue two or more hours. It can be administered by the mouth, hypodermically or intertracheally; as an antiseptic it diminishes oxidation, and promotes heat loss by dilating the cutaneous vessels, but more probably by depressing the activity of the calorifacient centers.

Uses.—Used in high fever where the temperature must be reduced quickly, as in sun-stroke, acute rheumatism; in man a solution of antipyrine from four to ten per cent strength up, is sprayed into the nostrils for hay-fever. Acetanilide is a better and safer and much cheaper drug for febrile diseases.