Licence: In copyright
Credit: The plant alkaloids / by Thomas Anderson Henry. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![drop by drop until the reaction is acid, and the ether evaporated on the water-bath. The residue is evaporated twice with 3 c.c. of alcohol to remove excess of acid and finally dried at a temperature not exceeding G0° and weighed. This weight multiplied by 0-777 X 20 gives the percentage of total alkaloids in the fruits. The United States Pharmacopoeia requires that it should not be less than 0-5 per cent. Fluid Extract of Hemlock Fruits. For this preparation the United States Pharmacopoeia prescribes the following process. Ten c.c. of the extract are placed in an evaporating dish con- taining a little clean sand, and evaporated to dryness. The residue is then placed in a flask with 100 c.c. of a mixture of ether 100 c.c., alcohol 7 c.c., and ammonia water (sp. gr. 0-958 at 25°) 3 C.C., the solvent being first used in portions to wash out the dish. After standing one hour with occasional agitation 50 c.c. of the clear liquid in the flask are decanted, and the process continued as described above for hemlock fruits. The fluid extract should contain 0-45 grin, of total alkaloids in 100 c.c. An alternative method of estimating the alkaloidal constituents of hemlock is that devised by Cripps ^ and improved by Farr and Wright.- Five grammes of the finely powdered fruits are mixed with sand and exhausted by percolation with a mixture of 95 per cent, alcohol 25 c.c., chloroform 15 c.c., and chloroform saturated with hydrogen chloride 10 c.c. The extract is shaken twice with 25 c.c. of distilled water, the latter clarified by shaking once with a few cubic centimetres of chloroform, made alkaline by addition of caustic soda solution, and the liberated bases extracted by agitation with chloroform, the latter being then run into excess of a saturated solution of hydrogen chloride in chloroform. The solvent is distilled off, and the residue of hydrochlorides dried at 90° in a cur- rent of air and weighed. Farr and Wright ^ have shown that this process gives good results with galenical preparations of the drug. The alkaloidal values (expressed as total hydrochlorides) of ^ Phann. Jouni. 1887-8 [iii], 18, 1.3, 511. ^ Ibid. 1891 [iii], 21, 857, 93(5. “ Loc. cif.](https://iiif.wellcomecollection.org/image/b2196189x_0037.jp2/full/800%2C/0/default.jpg)
