It is slightly soluble in water, but dissolves freely in alcohol, ether, and chloroform. When a one per cent. solution of it is treated with
potash or soda it rapidly acquires a characteristic rose colour. Heated in a flask with a water-bath in contact with excess of ammonia, it gives upon evaporation of the liquor in the open air, a magnificent blue colour, very soluble in the water. This solution treated with acids, produces a very fine dichroic liquor, violet and transparent by transmission, and carmine red and turbid by refraction. Eserine has the property of contracting energetically the pupil of the eye.
A kilogram of Calabar beans yields on the average one gram of eserine (from ‘Formulæ for new Medicaments, adopted by the Paris Pharmaceutical Society.’) See Calabar Bean.
Eserine, Neutral Hydrobromate of. This body is prepared with colourless hydrobromic acid in the same manner as the sulphate. The solution evaporated to a syrupy consistence, crystallises in the course of a few days in fibrous masses, rarely colourless and non-deliquescent.
The neutral hydrobromate of eserine is employed like the sulphate and in the same doses, although it contains a little less eserine. (From ‘Formulæ for New Medicaments,’ adopted by the Paris Pharmaceutical Society.) See Calabar Bean.
Eserine, Neutral Sulphate of. This salt is obtained by saturating directly and exactly a known quantity of eserine with dilute sulphuric acid (1 in 10); or better still, by shaking a solution of the eserine with a titrated solution of sulphuric acid so as not to exceed the point of saturation. The filtered solution of sulphate of eserine is evaporated rapidly to dryness by the aid of a gentle heat.
Sulphate of eserine can be crystallised in long prismatic needles, combined in radiating groups, but it is very difficult. It is preferable to preserve it in the amorphous state, and in well-stoppered bottles, as it is very deliquescent.
Sulphate of eserine is employed like eserine, internally under the form of granules containing up to one milligram. It is employed also for the eyes as a solution, containing two to five centigrams of the salt to ten grams of distilled water.
Solutions containing eserine, pure or combined, alter rapidly in contact with the air, becoming red; they should only be prepared in small quantities as required. (From ‘Formulæ for New Medicaments,’ adopted by the Paris Pharmaceutical Society.) See Calabar Bean.
ESPRIT. [Fr.] Spirit. This term is commonly applied to alcoholic solutions of the essential oils, and to various odorous and aromatic essences sold by the perfumers and druggists as articles of the toilet. See Essence, Spirit, &c.