Syrupus Pruni Virginiana.
By J. GEORGE ENGLER, PH.G.
The bark from which this syrup is made is obtained from Prunus serotina, and collected in autumn. On the recent shoots it is green or olive brown, polished, and has minute orange dots; afterwards it becomes darker and on the small trunks and larger branches is of a reddish or purplish brown, with scattered, oblong, horizontal dots characteristic of the cherry. Old trunks have a scaly bark not unlike some of the pines.
The wild cherry tree rarely attains a height of more than forty or fifty feet in Massachusetts. According to Dr. Richardson it grows as far north as the Great Slave Lake, in latitude 62°, but only attains the height of about five feet. In Maine it rises to about thirty feet, being seldom more than a foot in diameter. In western New York it grows to a great height and a large size, but along the Ohio river it is seen in its perfection, for it is found from twelve to sixteen feet in circumference and from eighty to one hundred feet high. The trunk is of uniform size and undivided to the height of about twenty-five feet. The wood is of a light red color, growing darker with age, and its medullary rays are very numerous and more closely arranged than those of most other woods. It is especially valuable in cabinet work and has of late years become very much in demand for fixtures in many pharmacies. The most beautiful portion commonly used is that where the branches begin. The bark is of a pleasant aromatic bittery leaving, when chewed, an agreeable taste in the mouth.
The U. S. P. process for preparing syrup of wild cherry is unsatisfactory on account of the unstability of the production and its liability to undergo fermentation. The remedy which suggested itself to me was the use of a quantity of either alcohol or glycerin. The object of my experiments has been to obtain a syrup that will remain permanent, under ordinary circumstances, with the smallest amount of these preservatives. To make a just comparison I first made a syrup according to the pharmacopoeial formula. This syrup was made March 1st, 1884; it had a rich brownish red color, the characteristic odor of hydrocyanic acid, and a slightly bitter, astringent taste. Placed on a shelf where it was subjected to the ordinary conditions of light and heat of the store, after eight weeks a slight cloudiness was formed, followed by a noticeable amount of precipitate, and fermentation soon began. With this change the syrup began to lose its color, and after nine months had lost all resemblance to a good syrup in color and odor, and it also had a thick fungous growth at the top.
Three syrups were next made in which the glycerin was replaced by alcohol in different proportions, and three in which the quantity of glycerin was increased in different amounts. Those made with alcohol show the following results: Number one, with four drachms of alcohol to the pint, kept almost perfectly for three months, then a slight precipitate began to form, which, after nine months standing, is quite noticeable; odor and color remain unchanged. Number two, made with one ounce of alcohol, remained unchanged somewhat longer, but a precipitate has formed. The color remains unchanged and the odor is slightly alcoholic. Number three, made with one and a half ounces of alcohol, remained permanent for a still longer time, color unchanged and a stronger alcoholic odor. The result of these three experiments with alcohol as a preservative show that this menstruum in practicable amounts is not satisfactory. The syrups made with increased quantities of glycerin showed the following results: Number four, with two ounces of glycerin to the pint, a bright syrup of beautiful color, and after standing nine months still remains unchanged. Number five, with two and a half ounces, and number six with three ounces of glycerin to the pint, gave permanent, bright syrups. The syrup was made by the following formula:
|Wild Cherry bark.||5 ounces,|
|Bitter Almond.||5 drams,|
Made according to the pharmacopoeial method a handsome syrup is obtained, permanent, and having a strong odor and taste of hydrocyanic acid. These results show that glycerin in somewhat increased amounts would make the syrup permanent.