178 ALIMENTATION. 



nin, or infusion of galls, added to a solution of gelatine, produces a brownish precipitate. 

 This reaction is marked in a solution containing but one part of gelatine to five thousand 

 parts of water. Both gelatine and chondrine are of indefinite chemical composition and un- 

 crystallizable. By the action of sulphuric acid, gelatine is %ransformed into a crystallizable 

 substance called glycocolle, which has a sweetish taste, is soluble in water, and is insoluble 

 in alcohol and ether. According to some, this is capable of being separated into alcohol 

 and carbonic acid by fermentation. 



A great deal of interest was at one time attached to gelatine as an article of food, 

 from the fact that it is formed and extracted from parts, particularly the bones, which 

 were before regarded as comparatively useless. Indeed, the experiment of diminishing 

 the quantity of meat and supplying in its place the extract of bones was made in several 

 hospitals and manufacturing establishments in France ; but this change in diet led so uni- 

 versally to complaints of insufficiency of food, that experiments were soon instituted with 

 a view of determining whether gelatine really possessed any nutritive power. "Without 

 entering into a full discussion of these experiments, it may be stated that the introduction 

 of gelatine as an article of diet, to the exclusion of other principles which were known to 

 be nutritive, was always followed by loss of weight and the indications of more or less de- 

 fective nutrition. In other words, the introduction of gelatine did not permit any diminu- 

 tion in the quantity of ordinary articles of food. The whole question was finally settled 

 by the researches of Magendie, the reporter of the French committee on gelatine, in 1841. 

 This report embodied the results of numerous experiments on the effects of various nitro- 

 genized principles, but the conclusions with regard to gelatine were very striking. When 

 taken alone, it was distasteful in the highest degree, even to animals on the verge of 

 starvation ; even the agreeable jelly formed of different parts of the pig and the giblets 

 of fowl, prepared by the charcuticrs of Paris, which were at first taken by the animals 

 with apparent satisfaction, was refused after a few days ; and, when animals were con- 

 fined exclusively to this article, death took place about the twentieth day, with all the 

 symptoms of inanition. 



The flavor of meat was formerly supposed to depend chiefly on a peculiar principle,, 

 called, by Thenard, osmazome. This name is now seldom used, as the substance which 

 was so called is known to be composed of various empyreumatic nitrogenized products, 

 with lactic acid, the lactate of soda, the inosate of potash, creatiiie, creatinine, and 

 other principles the nature of which has not been determined. 



Most of the vegetable articles of food contain more or less nitrogenized matters 

 which resemble very closely their analogues in the animal kingdom. Some of these vege- 

 table principles resemble those above considered so closely that they have been called 

 respectively, vegetable albumen, fibrin, and caseine. They all, however, present certain 

 distinguishing peculiarities. 



Vegetable Albumen. In the juice of most vegetables which are used as food, there 

 exists a substance, coagulable by heat and by alcohol, and having the same composition as 

 ordinary albumen with the exception of the equivalents of phosphorus and sulphur. 

 This is found most abundantly in the juice of turnips, carrots, cabbages, and vegetables of 

 this class. In wh eaten flour, which contains nearly all classes of alimentary principles, 

 it is also found, but in small quantity. 



There is every reason to suppose that, as nutritive principles, vegetable and animal 

 albumen are nearly identical. Many of the largest and strongest animals are nourished 

 exclusively from the vegetable kingdom. The human subject and many of the inferior 

 animals may be nourished at will by vegetable or by animal food. There is, however, 

 always a physiological difference in the various nitrogenized principles, which is not ap- 

 preciable by chemical analysis. The flesh of the carnivora, when used as food, is not the 

 same as the flesh of the herbivora; and the quality of the meat may be modified in many 

 animals by changing them from vegetable to animal food. Although the muscular tissue 



