tllKMISTRY OF THE LEUCOMAINES. 283 



embracing those bases which have been observed, but 

 studied more or less incompletely, in the various physio- 

 logical smvtions of the body. 



LEUCOMAKNES OF THE URIC ACID GROUP. 



ADENINE, C 5 H 5 N a , which was discovered by KOSSEL in 

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

 1 ucoma'ines, and as such it deserves special attention, inas- 

 much as it shows most clearly the relation that exists 

 In-twi-en 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 quajitity 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 <"*>/", meaning a gland. -It has since been shown to 

 mrur 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 to 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 been observed in the liver and urine of 



