One thousand experiments in chemistry : with illustrations of natural phenomena ; and practical observations on the manufacturing and chemical processes at present pursued in the successful cultivation of the useful arts / by Colin Mackenzie.

Date:
1821
Catalogue details

Licence: Public Domain Mark

Credit: One thousand experiments in chemistry : with illustrations of natural phenomena ; and practical observations on the manufacturing and chemical processes at present pursued in the successful cultivation of the useful arts / by Colin Mackenzie. 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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    very small portion of it. Alcohol and ether dissolve it very readily. The alcoholic solution renders syrup of violets green, and restores the blue tint of litmus, reddened by an acid. It forms neutral salts with the acids, which are very soluble; the alkalies precipitate the delphine in a white gelatinous state, like alumine. Brucine.—Another alkali has been lately discovered, to which the name of brucine has been given, from Mr. Bruce, the Abyssinian tra- veller having first made known the tree, the false Angustura, or Brucea antidysentericus ; from the bark of which, the new alkaline substance is obtained. The crystals of brucine,] when obtained by slow' evapora- tion, are oblique prisms, the bases of which are parallelograms. When deposited from a saturated solution in boiling water by cooling, it is in bulky plates, somewhat similar to boracic acid in appearance. When in this state, the water may be forced out of it by compression. It is soluble in 500 times its weight of boiling water, and 850 times its weight of cold water. Its taste is exceedingly bitter and acrid, and continues long in the mouth. Given in doses of a few grains, it is poi- sonous, and acts upon animals in the same way as strychnine. It is not altered by exposure to air; it may be melted by heat at a little above 212°, without decomposition, and thus appears like wax. When exposed to a strong heat it is decomposed. It combines with the acids, and forms neutral and bi-salts. All these salts easily crystallize. The action of brucine on the animal system is analagous to that of strychnine, but compared with it, its force is not more than as 1 to 12. It induces violent attacks of tetanus; it acts on the nerves without attacking the brain, or injuring the intellectual faculties. It required four grains to kill a rabbit; and a dog having taken three grains, suf- fered severely but overcame the poison. it is suggested that the alcoholic extract of the Angustura bark may be used with advantage in place of the extract of the vomica nut. It appears that this alkali is combined in the bark with gallic acid : the bark contains, besides, a fatty matter, gum, a yellow colouring matter, sugar in very small quantities, and ligneous fibre. In addition to the foregoing substances, some others have been disco- vered, as Vavqueline from the daphne alpine; ambreine from ambergrease; and leucine from wool, and particularly from the muscular fibre, (fxbrine,') which when treated with sulphuric acid, yields a particular white substance, which has been called leucine. When a solution of leucine, in lukewarm water, is evaporated spontaneously, a number of small isolated crystals are formed at its surface. They are flat, perfectly cir- cular, and have exactly the shape of the moulds of buttons, with a rim round their circumference, anil a point of depression in their centre. Leucine has the taste of the juice of meat. It appears to be specifically lighter than water. It melt3 at a temperature considerably above that of boiling water, and spreads an odour of putrid meat, subliming partly in the form of small white insulated crystals. Leucine dissolves easily in nitric acid, and produces fine colourless and divergent needle crystals, which are a new acid, analagous to the nilro-saccharic. This niiro-leucic acid forms with salefiable bases, salts which have quite a dif- ferent arrangement from the nitro-saccharales. Combined with lime it yields a salt, which crystallises in small rounded groupcs, and is unalter* ble in the air.
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