482 SPECIAL PHYSIOLOGY. 



chemical distinctions of the food, was clearly indicated by Prout, and 

 has been since established by the researches of Liebig, and many other 

 chemists. Prout divided all nutrient substances into albuminous 

 bodies, such as the albumen, fibrin, and casein of animals, and the 

 gluten and legumin of plants ; oleaginous substances, including the 

 animal and vegetable fats and oils; and saccharine matters, comprising 

 the various kinds of sugar. According to him, the typical form of 

 animal food, is that supplied, by nature, to the young of mammiferous 

 animals and man, viz., milk, in which fluid, casein represents the al- 

 buminous kind of nutritive substances; butter, the oleaginous kind; 

 and sugar of milk, the saccharine kind. Besides these, milk also sup- 

 plies water, and the mineral matters essential to the formation of the 

 tissues. 



A more exhaustive classification of the nutritive substances con- 

 tained in food, is that which follows : 



1. Albuminoid substances. From the animal kingdom, albumen, 

 whether derived from the white of eggs, from blood, or from the mus- 

 cular or nervous tissues ; syntonin, or the fibrinous element of muscle, 

 some of which is contained in the expressed juice of meat; globulin, 

 cruorin, and fibrin, from the blood ; casein, derived from milk : and the 

 vitellin of the yolk of eggs. The substance of the liver, pancreas, kid- 

 neys, and other glands, is also, in great part, albuminoid, mixed, how- 

 ever, especially in the first organ, with fat. The brain substance is also 

 highly nutritive, containing both albuminoid and fatty matter. In this 

 group, must be included, not only cruorin, or the coloring matter of 

 the blood, but also myochrome, or that of muscle, both of which 

 have an extraordinary affinity for oxygen. From the vegetable king- 

 dom, are obtained the albuminoid substance gluten, sometimes called 

 vegetable albumen, which is chiefly obtained from the seeds of the vari- 

 ous kinds of corn, and other grasses ; also legumin, which has been 

 compared to animal casein, and exists in large quantity in the seeds 

 of peas, beans, lentils, and other leguminous plants. Vegetable al- 

 bumen likewise exists, in small quantity, in the growing or soft tissues 

 of the various succulent edible parts of vegetables and fruit, such as 

 the cabbage, cauliflower, turnip, apple, pear, and orange. 



2. Crelatinoid substances. These, which are derived solely from the 

 animal kingdom, include jelly of various kinds, obtained from the gel- 

 atin-yielding tissues of animals, such as isinglass, which is the dried 

 sound, or air-bladder, of the sturgeon, the areolar and fibrous tissues, 

 tendons, and bones ; also chondrin, or the jelly obtained from carti- 

 lages. These several tissues, however, are not supposed to contain 

 gelatin or chondrin, when in their raw or uncooked state. Gelatinoid 

 substances are present in broths, jellies, and ivory bone-dust. So far 

 as their nutrient qualities are concerned, they must be distinguished 

 from the albuminoid substances. 



3. Oleaginous substances. These comprehend the animal fats and 

 oils, stearin, margarin, palmitin, and olein, the fatty matters of the 

 bile and of the brain, and those of the yolk of eggs ; and also the fatty 

 acids of butter, the butyric, capric, and caproic. To these must be 



