CHAPTER XV. 



CHEMISTRY OF THE LEUC0MAIN8. 



Under this head are classed those basic substances which exist 

 preformed in the proteids or other constituents of the body or are 

 produced as products of tissue metabolism. The proteid molecule is 

 usually the parent of the ptomains and also of the leucomains. The 

 distinction between these two groups is therefore necessarily imper- 

 fect and unsatisfactory. In the one case bacteria are at work and 

 split up the proteid, giving rise to ptomains. The latter are essen- 

 tially cleavage products and the differences which exist among these 

 bases are to be sought largely in the peculiar composition of the pro- 

 teid acted upon and perhaps to less extent in the individual germ 

 which is the active agent of destruction. The fact that few, if any, 

 of the ptomains can be shown to be synthetic products indicates that 

 the bacteria or their enzymes act largely as hydrolytic agents. 



Obviously, the living animal cell, through its enzyme, may produce 

 the same or similar basic products which, however, being non-bacterial 

 in origin are designated as leucomains. Furthermore, these basic sub- 

 stances may be liberated by the direct action of hydrolytic agents 

 other than enzymes. Thus, to illustrate, the nuclein molecule when 

 acted upon by bacteria yields the xanthin bases. The latter are 

 formed in the living animal and plant in tissue metabolism and also 

 result by the action of dilute mineral acids. The hexon bases, while 

 they have not been as yet found to be bacterial products, will un- 

 doubtedly be shown to be such, for the reason that they are formed 

 by the enzymes of yeast, of germinating plants, of pancreas and of 

 the liver, and because they are easily split off from proteids by the 

 action of acids. Again lecithin, the parent substance of cholin, is 

 widely distributed in plants and animals. It yields cholin when 

 acted upon by bacteria or by acids, or when it undergoes metabolism 

 in the living plant or animal. The same is true for the well known 

 ptomains, putrescin and cadaverin, which according to Lawrow are 

 formed, undoubtedly from lysin and arginin, in the sterile autodiges- 

 tion of pigs' stomachs. 



The first attempt at the systematic study and generalization of 

 these basic substances was made by Gautier, who applied to them the 

 name leucomains, a term derived from the Greek, Xsuy^wfia, signify- 

 ing white of eggs. Under this name he included all those basic 

 substances which are formed in animal tissues during life, in contra- 

 distinction to the ptomains or basic products of putrefaction. Many 



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