A dictionary of chemistry, on the basis of Mr. Nicholson's: in which the principles of the science are investigated anew, and its applications to the phenomena of nature, medicine, mineralogy, agriculture, and manufactures, detailed (Volume 1).
- Andrew Ure
- Date:
- 1821
Licence: Public Domain Mark
Credit: A dictionary of chemistry, on the basis of Mr. Nicholson's: in which the principles of the science are investigated anew, and its applications to the phenomena of nature, medicine, mineralogy, agriculture, and manufactures, detailed (Volume 1). Source: Wellcome Collection.
Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)
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![Ihe acids without generating ammonia or carbonic acid ; but when cyanide of pot- ash dissolves in water no change takes place; and neither ammonia, carbonic acid, nor hydrocyanic vapour, is given out, unless an acid be added. These are the .characters which distinguish a metallic cyanide from the cyanide of an oxide. From the experiments of M. Magendie it appears, that the pure hydrocyanic acid is the most violent of all poisons. When a rod dipped into it is brought in contact with the tongue of an animal, death en- sues before the rod can be withdrawn. Jf a bird be held u moment over the mouth of a phial containing this acid, it dies. In the Annales de Chimie for 1314 we find this notice : M. B. Professor of Chemis- try, left by accident on a table a flask con- taining alcohol impregnated with prussic acid ; the servant, enticed by the agreea- ble flavour of the liquid swallowed a small glass of it. In two minutes she dropped down dead, as if struck with apoplexy,, The body was not examined. Scharinger, a professor at Vienna, says Orfila, '• prepared six or seven months ago a pure and concentrated prussic acid; he spread a certain quantity of it on his naked arm, and died a little time thereaf- ter. Dr. Magendie has, however, ventured to introduce its employment into medi- cine. He found it beneficial against phthi- sis and chronic catarrhs. His formula is the following:— Mix one part of the pure prussic or hy- drocyanic acid of M. Gay-Lussac with 83 of water by weight. To this mixture he gives the name of medicinal prussic acid. Of this he takes 1 gros. or 59 gr. Troy. Distilled water, 1 lb. or 7560 grs. Pure sugar, 1$ oz. or 708| grs. And mixing the ingredients well together, he administers a table spoonful every morning and evening. A well written re- port of the use of the prussic acid in cer- tain diseases, by Dr. Magendie, was com- municated by Dr. Granville to Mr. Brande, and is inserted in the fourth volume of the Journal of Science. For the following ingenious and accu- rate process for preparing prussic acid for medicinal uses, I am indebted to Dr. Nim- mo of Glasgow : Take of the ferroprussiate of potash 100 grains, of the protosulphate of iron 842 grains; dissolve them separately in four ounces of water, and mingle them. After allowing the precipitate of the pro- toprussiate of iron to settle, pour off the clear part, and add water to wash the sul- phate of potash completely away. To the protoprussiate of iron, mixed with four ounces of pure water, add 135 grains of the peroxide of mercurv, and boil the Vor, ft * [12] whole till the oxide is dissolved. With the above proportions of peroxide of mer- cury, the protoprussiate of iron is com- pletely decomposed. The vessel being kept warm, the oxide of iron will fall to the bottom, the clew part may he poured oil to be filtered through paper, taking care to keep the funnel covered, so that cr\ stals inaj not form in it by refrigeration. The residuum may be treated with more water, and thrown upon the filler, upon which warm water ought to be poured, until all the soluble part is washed away. By evaporation, and subsequent rest in a cool place, 145 grains of crystals of the prusside or cyanide of mercury will be procured in quadrangular prisms. The following process for eliminating the hydrocyanic acid I believe to be new. Take of the cyanide of mercury in fine powder one ounce, diffuse it in two oun- ces of water, and to it, by slow degrees, add a solution of hydrosulphuret of bary- tes, made by decomposing sulphate of ba- rytes with charcoal in the common way. Of the sulphuret of barytes take an ounce, boil it with six ounces of water, and filter it as hot as possible. Add this in small por- tions to the cyanide of mercury, aguating the whole very well, and allowing suffi- cient time for the cyanide to dissolve, while the decomposition is going on be- tween it and the hydrosulphuret as it is added. Continue the addition of the hy- drosulphuret so long as a dark precipitate of sulphuret of mercury falls down, and even allowing a small excess. Let the whole be thrown upon a filter, and kept warm till the fluid drops through; add more water to wash the sulphuret of mer- cury, until eight ounces of fluid have pass- ed through the filter, and it has become tasteless. To this fluid, which contains the prussiate of barytes, with a small excess of hydrosulphuret of barytes, add sulphuric acid, diluted with an equal weight of wa- ter, and allowed to become cold, so long as sulphate of barytes falls down. The ex- cess of sulphuretted hydrogen will be re- moved by adding a sufficient portion of carbonate of lead, and agitating very well. The whole may now be put upon a filter, which must be closely covered; the fluid which passes is the hydrocyanic acid, of what is called the medical standard strength. Dr. Nimmo finds, that cyanide of mer- cury is capable of dissolving the mercuri- al peroxide. Hence, the above proportions must be strictly observed, if we wish to obtain this powerful medicine of uniform strength. He conceives, therefore, that the ferroprussiate of potash should be ta-. ken for the basis of the calculation, Scheele found that prussic acid occa- sioned precipitates with only the fouowiif£](https://iiif.wellcomecollection.org/image/b21160909_0113.jp2/full/800%2C/0/default.jpg)
