A neutral substance derived from aniline by the action of glacial acetic acid. A colorless crystalline powder of slightly burning taste, soluble in alcohol, but not readily so in water.

Its medicinal qualities are very similar to those of antipyrine, it being antipyretic, analgesic, and a nervous sedative. It has some differences of action. It diminishes the irritability of sensory nerves, lessens the reflex action of the spinal cord, raises arterial tension to some extent, and slows the heart correspondingly. The reduction of temperature by acetanilide takes place rather more slowly than that caused by antipyrine - sometimes twice as much time being required.

The effects last longer - six or seven hours - and the fall is sometimes, though not always, accompanied by perspiration rather less profuse than that produced by antipyrine. The lowering of the temperature is not supposed to depend on this diaphoresis, as experiments show that one sometimes follows without the other.

The antipyretic action of acetanilide is occasionally followed by cyanosis, and in rare cases by collapse, though it is usually considered less apt than antipyrine to produce severe depression, and in the majority of cases its use leaves no ill after-effects and does not nauseate. It has diuretic action and is a cerebral stimulant, while antipyrine depresses the brain. A poisonous dose destroys the ozonizing function of the blood.

Incidental effects noticed sometimes after its use are deafness, ringing in the ears, dilatation of the pupils, and an eruption similar to that caused by antipyrine.

Average dose, gr. iii.-0.2 Gm. It may be given in dilute alcoholic solution, and, like many remedies today, is put up in compressed tablets.

Allied to acetanilid, all unofficial, are:

Benzanilid. Antikamnia.

Antinervin.

Exodyne.

Phenolid.

Resorcinol, Resorcin.

Resorcinol is obtained from galbanum, a resin, by the action of alkalies. It is also made from phenol, thus belonging to the phenol group of derivatives of coal tar. It occurs as white crystals with an odor resembling phenol, and is soluble in water, and also in alcohol. It is antiseptic and disinfectant, inferior, however, in these respects to phenol. It has considerable antipyretic action, in large doses, causing free diaphoresis with reduction of the pulse and temperature. The pulse may, within an hour, be slowed by as much as one third its former number of beats, and the temperature fall three or four degrees, to remain down for from two to four hours, when it rises again rapidly. While rising there may be chilly feelings, or a distinct chill.

Doses which produce these results, viz., gr. xxx.-lx., cause also, as preliminary symptoms, dizziness, ringing in the ears, frontal headache, trembling, and quickened respirations. With the breaking out of perspiration these disturbances die away. No fatal case of poisoning is known. In one case, where 120 grains were taken, giddiness and a feeling as of the pricking of pins came on immediately. Unconsciousness followed, with subnormal temperature and thready pulse.

The chief action of resorcinol is upon the nerve centres, and it has been shown experimentally that very large doses paralyze the heart.

Average dose, gr. ii.-0.125 Gm.

It is used in an ointment, strength from 5 to 30 per cent.