Essence of Quin′ine

Syn. E entia quinæ , L. Prep. From disulphate of quinine, 1 1 ⁄ 2 oz.; rectified spirit, 1 ⁄ 2 pint; digest with warmth, gradually dropping in a little dilute sulphuric acid (avoiding exce ), and employing constant agitation until the whole is di olved. 1 fl. dr., added to 7 dr. of proof spirit, forms the ‘ TINCTURE OF QUININE ’ (Ph. L.). Every fl. dr. contains 8 gr. of disulphate of quinine, or about 10 gr. of the neutral sulphate. If more sulphuric acid is added than is sufficient to di olve the salt ( i. e. convert it into a neutral sulphate), the solution is apt to deposit part of it on keeping, owing to the gradual formation of ether, by the action of the exce of acid on the alcohol.