CHEMISTRY OF THE LEUCOMAINES. 313 



acidulated solution of guanine, when a light, crystalline 



preeipitate forms. Under the microscope it appears in 



prm-il-shaped. fern-like tufts of fine, orange-yellow needles. 



Physiologii -allv uuaniiir like uric acid is inert (FiLEHNE). 



XANTHINE, C 5 H 4 N 4 2 , is also very widely distributed in 



the organism, and has been met with in almost all the 



tissues and liquids of the animal economy. Together with 



hypoxanthine, guanine, and possibly adenine, it occurs in 



many plants, among which may be mentioned lupine, 



{ethalinm, sprouts of malt, tea-leaves (BAGINSKY), auto- 



diirestion of yeast, gourd seeds, sqja beans, etc. It was 



first discovered by MARCET (1819) in a urinary calculus, 



and since then has been frequently found as the only or 



chief constituent of many calculi. UNGER and PHIPSON 



have extracted it from guano, while SALOMON has shown 



it to be one of the products formed in the pancreatic diges- 



tion of fibrin. SCHUTZENBERGER found it together with 



carnine and hypoxanthine in the liquors from yeast. It is 



a normal constituent of the urine, but is present only in 



extremely minute quantities. During the use of sulphur- 



baths, or after the thorough application of sulphur salves, 



the quantity of xanthine in the urine is considerably in- 



creased. It is likewise more abundant in the urine of leuco- 



cythsemic patients, for the reasons already given on pane 



283. BAGINSKI holds that the amount of xanthine nor- 



mally present in the urine may be increased tenfold in the 



case of acute nephritis. BENCE JONES observed in the 



urine of a child sick with renal colic, a deposit of crystals 



which he considered to be xanthine, but other observers 



arc inclined to regard the crystals as those of hypo- 



xanthine. VAUGHAN has reported the presence of xan- 



thine in deposits from the urine of patients with enlarged 



spleen. 



Xanthine may be prepared synthetically in several ways. 

 Thus, it may be obtained by the reduction of nric acid by 

 means of sodium amalgam, according to the equation : 



C ft H 4 N 4 3 + H 2 = C 5 H 4 N 4 2 + H 2 O. 



T'RH- ACID. XANTHINE. 



