Under this name is described a polymeric modification of aldehyde. Above the temperature of 51° Fahr. it is a colorless liquid, having a peculiar ethereal odor, and a specific gravity of •998. It boils at about 225° Fahr. It is soluble in eight parts of water at 52° Fahr. The dose ranges from 3 ss to 3 ijss. Water is a suitable menstruum.

In appropriate cases it has proved to be an admirable hypnotic, with many of the qualities but none of the dangers of chloral. In its action, first the cells of the cerebrum are affected, and sopor is induced. Unlike the other agents of this class, its soporific action is not preceded by excitement (Cervello). Next to the cerebral hemispheres the effects of paraldehyde are expended on the medulla oblongata, and then on the spinal cord. A lethal dose stops the functioning of the medulla and the respiratory center, but the cardiac functions cease after the respiratory. It differs from chloral in the important respect that it has no paralyzing action on the heart. The effect of paraldehyde is, however, not so persistent as that of chloral, but frequent administration of the one can safely compensate for the greater power of the other (Albertoni).

Paraldehyde may be prescribed as a hypnotic in the conditions usually requiring such a remedy—in fevers, rheumatism, gout, prurigo, etc. (Morselli). It is, however, in mental and nervous disorders that it is likely to be most employed. By the Italian physicians, to whom we owe its introduction, it has been very successfully used in acute mania, in the wakefulness of dementia paralytica, in hysterical seizures, and in ordinary insomnia. To succeed, it must be given in sufficient quantity. The maximum dose mentioned above ( 3 ijss) has often been given without any ill effect or any after-trouble of any kind, and has often proved to be necessary.

Paraldehyde has gained in favor since its introduction, and the range of its application has constantly widened. It has been used with success in the treatment of delirium tremens, in strychnine-poisoning, in the milder cases of neuralgia, and as an expectorant; but in the more dangerous affections the dose must be large enough to make an impression—from 3 ss to 3 ij. These large doses are the safer, in that paraldehyde has no depressing action on the heart and lungs (Coudray). An increasing use as an expectorant, and as an ingredient of cough-mixtures, confirms what has been stated of its beneficial effects in the treatment of cough, and bronchial affections in general.

Although paraldehyde has an agreeable, fruity odor, the taste is rather pungent, and hence it were better given in the form of the prescriptions below:

Rx Paraldehyde, 3 j; spirit, chloroform., τη xv; pulv. tragacanth. com., Эj; syrp. aurant. cort., oz ss; aquae ad oz iij. M. Sig.: One or two doses (Hodgson).

Rx Paraldehyde., 3 ij; ol. amygd. ex., 3 ij; chloroformi, τη x; ol. cinnamomi, τη ij.

Authorities referred to:

Coudray, Dr. Thése de Paris, 1885, quoted by Annuaire de Thérapeutique, 1885.

Desnos, Dr. Bul. Gén. de Thérap. for 1886.

Dujardin-Beaumetz, Dr. Ibid.

Keraval et Nerkam. Annuaire de Thérap. for 1886.

Prevost, Dr. J. L. Bul. Gén. de Thérap. Ibid.