LEVCOMAiNS. 333 



of these bases exist preformed in plants or can be readily prepared 

 from them. 



Thus vegetable tissues are known to contain not only what are 

 ordinarily designated as ptomains, such as cholin, but also leuco- 

 mains, of the hexon and purin group. Indeed, in this latter group 

 must be placed, on account of their relation to xanthin, those well 

 defined alkaloidal bases, caffein, theophyllin and theobromin. Not 

 only are the representatives of these two divisions of basic substances 

 common to both kingdoms, but their parent bodies, lecithin, nuclein, 

 and proteids occur in both, and hence give rise to the same bases on 

 decomposition. 



Gautier believed that the leucomains are being formed continu- 

 ously and incessantly in the animal tissues side by side with the for- 

 mation of urea and carbonic acid, and at the expense of the nitrog- 

 enous elements. It is quite probable, as Kossel has pointed out, 

 that some of these products are in themselves antecedents of end- 

 products of metabolism. This is unquestionably true of the amido 

 group, which exists in the adenin and guanin molecules, and through 

 vital or putrefactive processes is split off", giving rise to ammonia 

 which in turn serves to form urea. More than that, the researches 

 of the past few years have shown that the purin and hexon bases, 

 while primary cleavage bodies, are largely broken down into more 

 simple metabolic products. Thus, the uric acid which is formed in 

 certain organs in the body of mammals is chiefly, if not wholly, de- 

 rived by the oxidation of the purin bases or of their antecedent. 

 The kidneys, muscles and even the liver itself may destroy uric acid, 

 and for that reason the amount of uric acid excreted does not indicate 

 the amount that is formed (Wiener). The cleavage of uric acid into 

 allantoin, oxalic acid and urea is well known, and Minkowski has 

 recently shown that allantoin is also formed after the administration 

 of purin bases, as well as of thymus glands. 



Bouchard endeavored to explain the presence of leucomains in 

 the urine, by supposing that they were originally formed in the 

 intestinal tract, from which they were absorbed into the system, to 

 be subsequently eliminated by the kidneys. This view has also been 

 brought forward by Schar (1886) who held that these bases may be 

 formed by putrefactive changes in the intestinal tract, in which case 

 they are absorbed into the circulatory system, whence they may be 

 partly eliminated by the kidneys or may be partly deposited in the 

 tissues themselves. 



The views of Bouchard and Schar have, to a certain extent, been 

 confirmed by the investigations of Udrinszky and Baumann, who 

 showed that the well known ptomains cadaverin and putrescin occur 

 in the urine in cystinuria, and are formed by putrefactive changes 

 induced in the intestinal tract, probably by specific microorganisms. 

 Under this same head fall the observations of Wolkow and Bau- 



