CHEMISTRY OF THE LEUCOMAINES. 283 



embracing those bases which have been observed, but 

 studied more or less incompletely, in the various physio- 

 logical secretions of the body. 



Leucomaines of THE Uric Acid Group. 



Adeniwe, C5H5N5, which was discovered by Kossel in 

 1885, forms the simplest member of the uric acid group of 

 leucomaines, and as such it deserves special attention, inas- 

 much as it shows most clearly the relation that exists 

 between hydrocyanic acid and the members of this group. 

 This base is apparently formed by the polymerization of 

 hydrocyanic acid — a view that is confirmed, at least in 

 part, by the fact that on heating with potassium hydrate 

 to 200°, it yields a large quantity of potassium cyanide. 

 Moreover, by the action of reducing agents, it is converted 

 into a substance similar to, if not identical with, azulmic 

 acid. It has not been prepared synthetically, though 

 Gautier has claimed to have synthesized two closely re- 

 lated bodies, xanthine and methyl-xanthine, by simple 

 heating of hydrocyanic acid in a sealed tube in contact with 

 water and a little acetic acid. 



This base was first prepared from pancreatic glands — 

 hence the term adenine, which is derived from the Greek 

 word a^'frv, meaning a gland. It has since been shown to 

 occur together with guanine, hypoxanthine, etc., as a 

 decomposition-product of nuclein, and, therefore, it may 

 be obtained from all tissues and organs, animal or vege- 

 table, rich in nucleated cells. Accordingly, it has been 

 found in the kidneys, spleen, pancreatic, thymus and lym- 

 phatic glands, in beer-yeast, in spermatic fluids, but not in 

 testicles of the steer ; occurs also in tea-leaves. In the latter 

 adenine appears \o exist in a preformed condition, since it can 

 be extracted without the use of acid reagents. The thymus 

 gland, as a prototype of embryonic, highly cellular tissue, 

 yields a considerable amount of adenine ; that from a calf, 

 for instance, was found by Schindler to contain 0.18 per 

 cent. It has also Ijccn observed in the liver and urine of 



