14 MANUAL OF OxVTrLE-FEEDma. 



blood of tlie Iiepatic vein (the vein leading from tlie liver 

 toward the heart), where the amount rises to about 0.1 

 per cent. 



The liver itself contains a considerable quantity of a sub- 

 stance called glycogen^ somewhat resembling starch, which 

 is continually yielding sugar by its decomposition. The 

 sugar in the hepatic vein has its source in the glycogen of 

 the liver. 



The muscles likewise contain glycogen, and also small 

 quantities of a non-nitrogenous substance peculiar to 

 themselves, and resembling sugar in composition and 

 properties, called 'modte. 



Furthermore, various non-nitrogenous organic com- 

 pounds occur in the bile, and innumerable such in the so- 

 called extractive matters of the tissues and juices, that 

 is in the mixture of substances obtained by treating the 

 liebh, etc., with alcohol. The '' extractive matters" give to 

 meat soup its agreeable taste and smell. The weight of 

 all these substances, however, is inconsiderable, and van- 

 ishes almost entirely in compaiison with the great quanti- 

 ties of fat and nitrogenous matter in the whole body. 



§ 3, KiTRoaEjsroTJs Organic Substances. 



Of the nitrogenous constituents of the body, there are 

 three principal groups to be considered, viz., the Albu- 

 3S0NOID8, Gej^^genotis Substances, and IIoeny Matters. 



The albuminoids are by far the most important of the 

 three, since all manifestations of animal life are dependent 

 chiefly on them and the organs wdiich are composed of 

 them, and since they furnish the material out of which 

 the members of both the other groups are formed ; while 

 the latter, once formed, do not appear to be capable of 



