Within a few years some valuable methods of keeping meats, fish, oysters, fruits, fruit juices, milk, butter, etc., in a healthful, nutritious, and palatable condition for a considerable time past the ordinary period of their decay have been discovered. In the following treatise we give the results of the most patient research in securing all the latest and most valuable information in regard to this important subject.
We will not deal with processes which necessitate complicated apparatus or which require almost impossible chemical combinations, but we will explain inventions which have undoubted value combined with as much simplicity in the preparation as the circumstances will permit.
Of all the anti-septic agents used for the purposes mentioned boracic acid is the favorite, and salicylic acid next in choice. Various other anti-septic agents are used and combined in different ways, according to the results of experiments. They are applied either by immersion, coating, injecting, vapors, etc., according to specified instructions.
Prof. Frederic S. Barff of Kilburn, England, it seems was the first to combine boracic acid with glycerine, and to produce a preservative compound known as boroglyceride, which is soluble in water and alcohol. As boracic acid is but slightly soluble in water and other common solvents this combination with glycerine—which is also a useful agent in arresting the growth of germs—is peculiarly valuable. It is tasteless and inodorous and imparts no disagreeable taste or odor to the substance being treated. Solutions of the compound may be applied to the preservation of all organic substances, either animal or vegetable. The process was patented in England in 1881 and in the United States in 1882.
To prepare boroglyceride, glycerine is heated to near its boiling point and boracic acid added until it ceases to be dissolved, the proportions being about 92 parts by weight of glycerine to 62 parts by weight of boracic acid in chrystals. Maintain the mixture to a temperature of about 200 deg. centigrade as long as water is given off. When the mass cools it becomes a yellowish, transparent, glacial substance, tough and deliquescent. This dissolves in water, but when boiled in large quantities of the same it is decomposed into glycerine and boracic acid. In order to employ the compound prepare a solution either in water, alcohol, or other suitable solvent and immerse in or impregnate with such solutions the organic substances to be operated upon. Solutions may be prepared of various degrees of strength, but it has been found that a solution consisting of 1 part by weight of the compound and 40 parts by weight of water will give good results; but other desired proportions may be adopted.
Prof. Barff, the inventor of the boroglyceride process, read a paper before the Royal Society of Arts, London, in regard to his method of preserving food. The date of the reading is not at hand, but it is supposed to be slightly prior to May 13, 1882, on which date it was printed in the Scientific American Supplement. Although quite lengthy the paper contains so much interesting data and light upon the subject that we reproduce it almost entirely, together with remarks by other eminent gentlemen who were present at the meeting:
“This evening I have on the table specimens of food which have been kept for longer or shorter periods, as they are intended to illustrate various applications of this preserving material. As you know oysters are imported very largely in tins. They are cooked at a high temperature and hermetically sealed. The high temperature to which they are exposed necessarily causes a loss of flavor, and it is generally remarked that tinned oysters are not a success. * * * I have oysters on the table which were opened on the 3d of December in last year. I will ask you to taste them and see in what condition they are, and I would also remind you that they have not been kept in hermetically sealed tins, but simply in corked or stoppered bottles; hence this method of preserving oysters is cheaper than the other, and I maintain that it is more effective, because their natural and fresh flavor is preserved. I am informed by a friend in Jamaica that he has sent me some Jamaica oysters and other things—I trust they will be here in time for me to submit them to you this evening.
“Another substance, the perfect preservation of which is very important, is cream, both for home use and for exportation. Cream in London costs from four to five shillings per quart; it can be bought in country places for two shillings, and even for less. This preservative substance will keep cream for months perfectly good and sweet, having its full flavor; so that it would be quite possible to send it in quantities from the country, and its sale need not be pressed as it need not be used immediately. I have regularly every week, except during the holidays, brought with me from Beaumont College, near Windsor, where I lecture, a quart of cream treated with one ounce of the boroglyceride; it has always kept perfectly good even in the hottest weather. I have done this for a year and a half; a near relative has taken the greater part of this regularly for the time stated, and this proves conclusively that there is nothing at all injurious to health in the compound. I see a gentleman present here to-night who is connected with that college as a professor of natural science, and he will, in the discussion, be able to give you very valuable information as to the material and as to its perfect wholesomeness. Last month I sent some cream to the Rev. J. Ryan, a Jesuit priest in Jamaica, and I have received a letter from him, from which I will read you an extract:
‘26 North Street, Kingston, Jamaica,
‘February 24, 1882.