THE ORGANIC CONSTITUENTS OF THE URINE. 249 



destruction. In many cases of this kind the increased elimination 

 is apparently dependent upon the amount of animal food that is in- 

 gested, and it would appear that in such cases the liver has lost to a 

 greater or less degree its power of oxidizing the uric acid, which 

 reaches it from this source. Were this true, we should then also 

 expect that relatively larger amounts of xanthin bases should find 

 their way into the urine, and this indeed may actually occur. But, 

 on the other hand, an increased elimination of uric acid and xanthin 

 bases may also be observed although the patient has been placed on 

 a diet which is practically free from nucleins. An adequate expla- 

 nation of such an occurrence is as yet wanting. We may suppose 

 that the liver has lost its power of oxidation so far as the xanthin 

 bases are concerned. But we must bear in mind that uric acid is 

 formed in all the tissues of the body, and that the relative amount 

 which thus originates, as compared with the xanthin bases, is largely 

 influenced by the intensity of the process of oxidation (absence of 

 uricolytic ferments?). It is hence also conceivable that in such 

 cases these may be deficient, while the liver may function in a nor- 

 mal manner. The possibility of a synthetic production of uric acid, 

 finally, may also enter into consideration. 



The question of the nature of the so-called uric-acid diathesis is 

 thus still in statu quo, and the same may be said of the formation 

 of uratic deposits in the joints and tendons in gout. It appears, 

 however, that an increased production of uric acid, contrary to what 

 was formerly supposed, plays no role in the causation of the latter 

 disease and that the essential abnormality consists in the inability 

 of the body to break down the uric acid to simpler and more readily 

 soluble products. 



Properties of Uric Acid. Pure uric acid crystallizes in trans- 

 parent, colorless rhombic platelets, the angles of which are often 

 rounded off. Such crystals are at times seen in urinary sediments, 

 but more commonly the substance is here found in tffe form of 

 brownish-yellow whetstone-like crystals, which may occur singly, 

 but are frequently arranged in groups. These are quite character- 

 istic, and cannot be confounded with crystals of any other substance 

 that may occur in the urine. 



A great many other forms may, however, also be encountered, 

 such as dumb-bells, somewhat irregular hexagonal platelets, paddle- 

 shaped crystals, etc., the nature of which is not at once apparent. 



Uric acid is almost insoluble in cold water (1 : 40,000), with 

 difficulty also in boiling water (1 : 1800), and insoluble in alcohol 

 and ether. 



In concentrated sulphuric acid and boiling glycerin it dissolves 

 with comparative ease and without undergoing decomposition. It is 

 a dibasic acid, and accordingly combines with bases to form neutral 

 and acid salts. Of these, the neutral salts of potassium and 

 lithium are the most soluble, while the acid salts, and notably acid 

 ammonium urate, are quite insoluble. Its compounds with the 



