Synonym. aether Sulphuricus. Edin. Dub.

Prep. Ether is prepared by the action of sulphuric acid upon alcohol, the proportion of acid employed being much less than that used in the formation of oleum aethereum, which was formerly officinal. In the British Pharmacopoeia ten fluid ounces of sulphuric acid are made to act upon fifty fluid ounces of rectified spirit added in successive portions.

The exact nature of the changes which occur during etherifica-tion is a subject which will be found discussed at some length in books of chemistry; the following remarks will perhaps suffice to give some idea of the process.

When alcohol and strong sulphuric acid are heated together, a peculiar acid is formed, named sulphovinic acid, represented by the formula C4 H5 O, 2 So3 HO; if this acid is distilled at a temperature of about 300°, a decomposition occurs which may be thus represented: - C4 H5 O, 2 So3 HO + HO = C4 H5 O + 2 (So3 HO); one of the products, oxide of ethyl or ether (C4 H5 0), being volatile, distils over, and sulphuric acid remains; by the addition of more alcohol, sulphovinic acid is again formed, and again decomposed; and by a continuous and slow supply of alcohol, the formation of the ether is rendered continuous.

Ether is purified by allowing it to stand upon chloride of calcium and slaked lime, and re-distilling until it becomes of sp. gr. 0.735.

Prop. & Comp. Ether is a very volatile, colourless liquid, with a peculiar, agreeable, fragrant odour and hot taste; sp. gr. 0.735 [0.750. U. S. aether Fortius, a sp. gr. not exceeding 0.728. U. S.]; is entirely dissipated in vapour when exposed to the air, and has scarcely, if any, acid reaction; very inflammable, burning with a white flame; it boils below 105°. A little poured upon the hand evaporates rapidly, producing a sensation of cold. It consists of oxide of ethyl (C4 H5 O), with about 8 per cent. by volume of alcohol and water. Fifty measures agitated with an equal volume of water are reduced to 41 by an absorption of 18 per cent. It evaporates without residue.

Off. Prep. Spiritus aetheris. Spirits of Ether. [Not officinal in U. S. P.] (Ether, ten fluid ounces; rectified spirit, twenty fluid ounces. Mix.) Sp. gr. 0.809.

[Spiritus Etheris Compositus. Compound Spirits of Ether. Hoffman's Anodyne. Ether, half a pint; alcohol, a pint; ethereal oil, six fluid drachms.]

Use. Ether is also made use of in the Pharmacopoeia for preparing one tincture, Tinctura Lobelias aeEthereae, and for making Collodion.

Therapeutics. Taken internally, ether is a powerful diffusible stimulant, more rapid and evanescent in its action than alcohol; it is used to expel flatus from the stomach, and allay pain and cramp in that organ, to diminish spasm in various other affections, as in spasmodic asthma, angina pectoris, and hysteria. When applied externally it produces cold, from the rapid evaporation, and is occasionally made use of as a refrigerant, in the reduction of hernia; if the vapour is confined, then rubefacient effects are produced. Inhaled in the form of vapour it acts in a manner not unlike chloroform, under which article the effects are described.

Dose. Of ether, 20 min. to 1 fl. drm.; of spirit of ether, 1/2 fl. drm. to 1 1/2 fl. drm.