After trying several other reagents, the foregoing were those which were found to afford the most satisfactory results, and appeared to be conclusive with regard to those adulterations, likely to be practised.—Pharmaceutical Journal, London.
ON HOFFMAN’S ANODYNE LIQUOR. BY WILLIAM PROCTER, JR.
Perhaps in no preparation in general use does the practice of manufacturers, and the requirements of pharmacopœial authorities, more widely differ than in the compound spirit of {210} ether, universally known as Hoffman’s Anodyne Liquor. According to the United States and London Pharmacopœias it consists of three fluid drachms of heavy oil of wine (Oleum Ethereum, U. S. P.,) dissolved in a mixture of eight fluid ounces of ether and sixteen fluid ounces of alcohol. The Edinburgh Pharmacopœia has only the simple spirit of ether, without the oil of wine, whilst the Dublin Pharmacopœia of 1850 under the name of Spiritus Æthereus Oleosus, gives the following formula, which includes the preparation of the oil of wine and its subsequent solution, to make the anodyne:—Mix a pint of alcohol and a pint and a half of oil of vitriol in a glass matrass, adapt a Liebig’s condenser, and by heat distil until a black froth rises. Separate the lighter etherial liquid in the receiver, expose it for 24 hours in a capsule, wash the residual oil with water, and dissolve it in a mixture of five fluid ounces of ether, and ten fluid ounces of alcohol. In France, Hoffman’s anodyne consists of equal parts of ether and alcohol, without oil of wine.
Owing to the careless or intentionally mystified manner of expressing himself, it is impossible now to ascertain whether the original preparation of Hoffman (published in 1732) was constant in its strength, as now recommended by the Pharmacopœia. Beaumé, (as quoted in Macquer’s Chem. Dict., London, 1771,) says, in speaking of the rectification of sulphuric ether, “By distilling the liquor in the first receiver, together with a very small quantity of oil of tartar, by a very gentle heat of a lamp furnace, about two pounds and four ounces of pure ether may be obtained; and afterwards, when a new receiver is adapted, and a stronger heat applied, from eight to ten ounces of aromatic liquor, which makes a good anodyne mineral liquor of Hoffman, will be distilled.”
The third edition of Lewis’ Dispensatory, published at Dublin, 1768, has the following formula for this preparation, which appears to be what the apothecaries of that day employed:—
“Hoffman’s Mineral Anodyne Liquor.”
Into half a pound of concentrated oil of vitriol, placed in a {211} large glass retort, pour by little and little, through a long stemmed funnel, one pint and a half of highly rectified spirit of wine. Stop the mouth of the retort, digest for some days, and then distil with a very gentle heat. At first a fragrant spirit of wine will arise; and after it a more fragrant volatile spirit, to be caught in a fresh receiver. The receiver being again changed, a sulphurous, volatile, acid phlegm comes over, and at length a sweet oil of vitriol, which should be immediately separated, lest it be absorbed by the phlegm. Mix the first and second spirits together, and in [every] two ounces of this mixture dissolve twelve drops of the sweet oil. If the liquor has any sulphurous smell, re-distil it from a little salt of tartar.
“Whether this is the exact preparation, so much recommended and so often prescribed by Hoffman as an anodyne and anti-spasmodic, we cannot determine. We learn from his own writings that his anodyne liquor was composed of the dulcified spirit of vitriol, [crude ether] and the aromatic oil which rises after it; but not in what proportions he mixed them together. The College of Wirtemburg seems to think that all the oil was mixed with all the spirit obtained in one operation without regard to the precise quantities.”
The product of this recipe must have been analogous to the present officinal spirit, the formula for which is evidently modeled after it. The great excess of alcohol distills over first, until the boiling point rises to the ether producing temperature, when ether is obtained, and finally the sulphurous oily product. The recipe gives no direction to isolate the oil of wine before measuring it, which is perhaps less necessary, as the ethereal part of the distillate is removed previously to the production of the oil which is found in the receiver in globules, and not in solution.
The process now adopted by the manufacturers in this city, avoids the isolation of the oil of wine, and from the nature of the conditions the product is liable to vary in the proportions of its ingredients, not only in different laboratories, but at different operations in the same laboratory. In the preparation of ether it is usual in this city to push the process as far as {212} possible, as long as the residue is not so concentrated as to eliminate much permanent gas. In the rectification of this first crude product, the distillate is reserved as rectified ether as long as its specific gravity marks 54° Beaumé, or there about. By continuing the process the product is found to consist of ether, alcohol and water, impregnated with oil of wine. Every one who has made ether, knows how very liable the product is to vary with an ill regulated heat; on the one hand unaltered alcohol will pass over, if the temperature is too low, whilst too great a heat, especially towards the last of the process, will favor the formation of oil of wine and sulphurous acid. This last distillate, therefore, will vary in composition, and it is from this that Hoffman’s anodyne is made in some of the best of our laboratories. There is no known practicable method of ascertaining the per centage of heavy oil of wine in this liquid. The means used by the manufacturer are founded on the sensible properties of an arbitrary standard specimen of Hoffman’s anodyne previously made, and on the degree of opalesence or milkiness it produces when added to a certain measure of water.—This milkiness is occasioned by the oil of wine present; but experience has shown that the degree of milkiness is not strictly in proportion to the quantity of oil present, the relative proportion of ether and alcohol, and perhaps water present in the anodyne liquid has a marked influence on the phenomenon; if too much alcohol, the milkiness is not produced, or but partially; if too much ether, oily globules separate and float with but moderate opalescence. In converting this second etherial distillate into commercial Hoffman’s anodyne, the operator has to make several essays, sometimes adding water, sometimes alcohol or ether, until the taste, the smell, and the opalescence agree, as nearly as can be approached, with his standard specimen. In the process of rectification it is probable that at least a part of the heavy oil of wine is decomposed, with the production of the light oil or etherole, and that the commercial Hoffman’s anodyne differs in this respect, as well as in containing a much smaller proportion of oil of wine, from that of the Pharmacopœia. {213}