210 DIGESTIVE SYSTEM. 



glossy and thicker hair, a more healthy appearance, are more 

 sprightly and active, etc. 



Attempts have been made, but without success, to substi- 

 tute chloride of potassium for the sodium salt ; it has been 

 found, however, instead of possessing the useful properties 

 of the latter, to produce serious injury. 1 



2. The principal aliments are those furnished by the animal 

 kingdom, that is the different forms of albumen, designated 

 under the common name of proteine substances, and several 

 other similar elements classed together under the name of 

 caseines. All these substances contain Oxygen (0), Hydro- 

 gen (H), Carbon (C), and Nitrogen (N), besides a certain 

 quantity of Sulphur (S) and Phosphorus (P), mineral salts, 

 etc. They also contain, probably, iron in small quantities, 

 though this is not yet proved in all cases. 



Some vegetable products supply the same aliment, such 

 as gluten or. vegetable fibrine, which is found in many seeds, 

 particularly cereals; vegetable albumen, found in emulsive 

 seeds and vegetable juices, and legumine or vegetable caseine, 

 found in large quantities in the seeds of leguminous plants. 

 These substances may all be classed under the name of 

 albuminoids. The transformations undergone by the albu- 

 minoid substances contained in plants bear a striking resem- 

 blance to those which take place in the animal economy, and 

 which we shall proceed to examine. During the germina- 

 tion of seeds, the albuminoid substances contained in plants 

 give rise to digestive ferments bearing the essential features 

 of some of the ferments furnished by the animal organs. 

 Thus the diastase produced by the germination of cereals, 

 closely resembles the ferment which we shall see is found in 

 the saliva and in the pancreatic juice. 



3. Next come the ternary, non-nitrogenous (ornon-azotized) 

 principles containing (C), (H), and (O), in the proportions re- 

 quired for the formation of sugar, starch, dextrine, gum, and 

 various mucilages ; all of these substances are incapable of 

 directly forming globules, the prevailing matter of which is 

 nitrogen. These substances are derived chiefly from the veg- 

 etable kingdom ; they are also found in animal food, but in very 

 small quantities. Sugar is found in milk, in the liver, and in 

 the blood which flows from this organ ; it has been discovered 



1 See Cl. Champy, " iStude comparee de 1' Action Physiologique 

 des Sels Potassiquos et Sodiques et de leurs Chlorures." These de 

 Strasbourg, 18fO, No. 290. 



