URINE 419 



greenish fluorescence. If the solution is turbid it may be rendered clear by the 

 addition of a few cubic centimeters of absolute alcohol. 



C. UROERYTHRIN 



This pigment is frequently present in small amount in normal urine. 

 The red color of urinary sediments is due in great part to the presence 

 of uroerythrin. It is easily soluble in amyl alcohol, slightly soluble in 

 acetic ether, absolute alcohol, or chloroform, and nearly insoluble in 

 water. Dilute solutions of uroerythrin are pink in color while concen- 

 trated solutions are orange red or bright red; none of its solutions 

 fluoresce. Uroerythrin is increased in amount after strenuous physical 

 exercise, digestive disturbances, fevers, certain liver disorders, and in 

 various other pathological conditions. 



PTOMAINES AND LEUCOMAINES 



These toxic substances are said to be present in small amount in 

 normal urine. Very little is known definitely, however, about them. 

 It is claimed that five different poisons may be detected in the urine, 

 and it is further stated that each of these substances produces a spe- 

 cific and definite symptom when injected intravenously into a rabbit. 

 The resulting symptoms are narcosis, salivation, mydriasis, paralysis, 

 and convulsions. The day urine is principally narcotic and is 2-4 times 

 as toxic as the night urine which is chiefly productive of convulsions. 



PURINE BASES 



The purine bases found in human urine are adenine, carnine, epi- 

 guanine, episarkine, guanine, xanthine, heteroxanthine, hypoxanthine, 

 paraxan thine, and i-methylxan thine. The main bulk of the purine 

 base content of the urine is made up of paraxanthine, heteroxanthine 

 and i-methylxanthine, which are derived for the most part from the caf- 

 feine, theobromine, and theophylline of the food. The total purine 

 base content is made up of the products of two distinct forms of metabo- 

 lism, i.e., metabolism of ingested nucleins and purines and metabolism 

 of tissue nuclein material. Purine bases resulting from the first form of 

 metabolism are said to be of exogenous origin, whereas those resulting 

 from the second form of metabolism are said to be of endogenous origin. 

 The daily output of purine bases by the urine is extremely small and 

 varies greatly with the individual (16-60 mg.) . The output is increased 

 after the ingestion of nuclein material as well as after the increased de- 

 struction of leucocytes. A well-marked increase accompanies leukemia. 

 Edsall and others have shown that the output of purine bases by the 



