On Baptisia Tinctoria.
By JOHN A. WEAVER.
(Extracted from the Author's Inaugural Essay.)
[After giving a short botanical description of the plant, the author describes the root and its medicinal properties, and refers to the examination of Mr. B. L. Smedley published in Vol. XXXIV of this Journal, 1862, page 311. We extract the following from Mr. Weaver's experiments:]
Experiment 1st. Fifty troy ounces of the root was boiled with successive portions of water acidulated with hydrochloric acid, until completely exhausted. The decoctions were mixed, strained, and while still hot, precipitated by a dilute milk of lime. The precipitate was copious, of a snuff-brown color and disagreeable odor. The mother-liquor was reddish brown, and refused to yield further precipitate by the addition of ammonia. The precipitate was thoroughly washed with water, and after being dried and powdered was digested in boiling alcohol and filtered. The alcohol recovered by distillation left a brown, viscid mass behind. This was treated with water acidulated with sulphuric acid, boiled a few minutes with animal charcoal and filtered. The result was a clear, colorless liquid. Upon the addition of ammonia to a small portion of this, a white precipitate was obtained.
This was the process followed by Mr. Smedley, and this the "white feathery precipitate" supposed by him to be the alkaloid. A portion was collected and dried, found to be insoluble in water, alcohol or chloroform. It was inodorous, had but little taste and possessed none of the properties of an alkaloid. Dissolved in water acidulated by hydrochloric acid, nearly neutralized with ammonia, and oxalate of ammonia added, a white precipitate was at once formed, showing the presence of lime. To ascertain to what extent it was composed of this, or whether it contained anything else, I added the whole of the first solution to an equal bulk of alcohol. The lime being insoluble in this, separated, and was collected on a filter; from the filtrate the alcohol was recovered, and the remaining liquid still gave a precipitate with ammonia. This was white, inodorous and tasteless. Ignited upon platinum foil, it did not volatilize, but swelled up and left a spongy charcoal behind, which, on being heated with a drop of nitric acid, became white.
These experiments were carefully performed, and each one repeated several times, always showing the same result. So I am prepared to say, that what was formerly regarded as the vegetable alkaloid of Baptisia tinctoria was, in reality, a salt of lime.
Experiment 4th. To a concentrated tincture of the root was added sufficient sulphuric acid to cause it to redden litmus, and the evaporation carried on until a small bulk was obtained. This was mixed with an equal bulk of water and filtered. The filtrate, on standing, separated into two layers, a heavy oily liquid and a lighter, more fluid one. To the lighter liquid was added a large quantity of water which threw out the remaining resin, and, upon filtration gave a clear solution not affected by more water. Upon testing a quantity of this with Mayer's test, a copious precipitate was obtained. To another portion chloroform was added, shaken together and allowed to separate. The alkaloid being in the form of sulphate, was supposed to be insoluble in that menstruum, while most of the remaining oil and coloring matter was removed. After removing the subsiding liquid I added, first, solution of potassa in excess, then chloroform, shook them together and again separated the chloroform, which, on spontaneous evaporation, left a small quantity of a light yellow substance behind. Upon testing the lighter portion of the solution with Mayer's test, a copious precipitate was still obtained, showing that more of the alkaloid still remained than was taken up by the chloroform. I therefore precipitated the whole of it by an excess of iodohydrargyrate of potassium. The precipitate was collected, suspended in water, and decomposed by hydrosulphuric acid, which threw down black sulphide of mercury, and left the alkaloid as an iodide in solution. This solution was concentrated, and carbonate of ammonia added in slight excess. It was then shaken with chloroform, which, on being separated and evaporated, left an amorphous mass behind. This was dissolved in water acidulated with hydrochloric acid, boiled for a few minutes with purified animal charcoal and filtered. Upon concentrating this to one third its bulk, long needle-like crystals were formed. The mother liquor, upon being further concentrated, yielded more crystals, and by evaporating to dryness left a yellowish crystalline mass. This I thought to be the alkaloid, but by igniting on platinum foil, a large residue was left. I then digested the whole of it in alcohol, filtered and evaporated. The residue was of a yellowish color, amorphous, disagreeable odor and extremely nauseous and acrid taste. But it had an acid reaction, owing to free hydrochloric acid, of which, unfortunately, it had not been entirely deprived before dissolving in the alcohol.
Being unable, for want of time, to repeat these last experiments, I was obliged to let the matter rest unfinished. But I am satisfied that when the alkaloid is isolated, this will be the proper course to pursue. The portion remaining undissolved in the alcohol, I afterwards found to be lime. In the course of my manipulations I found much resin, and a large quantity of a heavy fixed oil.
These experiments were conducted in the laboratory connected with our College, where, having every facility and the best of advice, I was enabled to proceed with accuracy.