delicacies of the Orient, the edible birds'-nests, the sea-slugs, etc., so highly esteemed for their nutritious properties, are varieties of gelatine.
About fifty or sixty years ago the French Academy of Sciences appointed a bone-soup commission, consisting of some of the most eminent savants of the period. They worked for above ten years upon the problem submitted to them, that of determining whether or not the soup made by boiling bones until only their mineral matter remained solid, is or is not a nutritious food for the inmates of hospitals, etc. In the voluminous report which they ultimately submitted to the Academy, they decided in the negative.
Baron Liebig became the popular exponent of their conclusions, and vigorously denounced gelatine, as not merely a worthless article of food, but as loading the system with material that demands wasteful effort for its removal.
The Academicians fed dogs on gelatine alone, and found that they speedily lost flesh, and ultimately died of starvation. A multitude of similar experiments showed that gelatine alone would not support animal life, and hence the conclusion that pure gelatine is worthless as an article of food, and that ordinary soups containing gelatine owed their nutritive value to their other constituents. According to the above named report and the statements of Liebig, the following, which I find on a wrapper of Liebig's "Extract of Meat," is justifiable: "This extract of meat differs essentially from the gelatinous product obtained from tendons and muscular fiber, inasmuch as it contains eighty per cent of nutritive matter, while the other contains four or five per cent." Here the four or five per cent allowed to exist in the "gelatinous product" (i. e., ordinary kitchen stock or glaze) is attributed to the constituents it contains over and above the pure gelatine.
Subsequent experiments, however, have refuted these conclusions. I must not be tempted to describe them in detail, but only to state the general results, which are, that while animals fed on gelatine-soup, formed into a soft paste with bread, lost flesh and strength rapidly, they recovered their original weight when to this same food only a very small quantity of the sapid and odorous principles of meat were added. Thus, in the experiments of Messrs. Edwards and Balzac, a young dog that had ceased growing, and had lost one fifth of its original weight when fed on the bread and gelatine for thirty days, was next supplied with the same food, but to which was added, twice a day, only two tablespoonfuls of soup made from horse-flesh. There was an increase of weight on the first day, and "in twenty-three days the dog had gained considerably more than its original weight, and was in the enjoyment of vigorous health and strength."
All this difference was due to the savory constituents of the four tablespoonfuls of meat-soup, which soup contained the juices of the flesh, to which, as already stated, its flavor is due.