THE NUCLEOPROTEIDS. 299 



atoms which are replaceable by radicals in the uric acid molecule, only 

 two take part in the formation of salts. Uric acid is, therefore, a dibasic 

 acid, and forms two series of salts, the acid or monobasic salts, and the 

 neutral or dibasic salts. Thus we have acid sodium urate, also called 

 monosodium urate, and neutral or disodium urate. Many speculations 

 have been brought forward regarding the deposition of uric acid in the 

 tissues, especially those of the joints, in gout, basing them upon the diffi- 

 cult solubility of uric acid. On the one hand, an increased formation of 

 uric acid may account for its elimination, and on the other hand the com- 

 position of the blood, lymph, and other constituents of the tissues may be 

 such that the uric acid is even more insoluble than under normal conditions. 

 All of these hypotheses have failed to be very fruitful. They have no 

 good foundation. For example, we do not know in what form the uric 

 acid is transported in the blood and tissues. The assumption has been 

 made that it circulates, not in a free state, but combined with albumin, 

 nucleic acids, and other substances, although no positive proof has yet 

 been presented that such is the case. No conclusions can be drawn from 

 the deposits themselves, which consist of monosodium urate. Great 

 stress was formerly laid on the increased presence of uric acid in the blood. 

 We know to-day, that other conditions may result in an increase of uric 

 acid in the blood without causing the appearance of the symptoms of gout. 

 Weintraud * has in fact shown that in a normal individual there is an 

 increased amount of uric acid in the blood after a diet rich in purine bases. 

 Again, great stress was laid upon the increased elimination of uric acid in 

 gout until it was positively shown that it is permissible to speak of an 

 increased elimination only during an acute attack. Otherwise aside 

 from the fact that in gouty diseases the purine values of the urine vary 

 more than under normal conditions the amount of purine present in 

 the urine is practically the same during a long period of time. 



It is very noticeable that the deposition of uric acid, especially in gouty 

 inflammations, seems to be confined to specific locations, such as the 

 smaller joints of the extremities. The suggestion has been made that 

 the primary cause of the whole ailment is not a disturbed metabolism of 

 the purine substances, but an alteration of the tissues at the place in ques- 

 tion. Just as it has been assumed that the formation of gall-stones is 

 due primarily to an inflammation of the biliary passages, and likewise that 

 renal calculi may originate from some organic lesion, the assumption 

 has also been made that the circulating uric acid was deposited at a given 

 spot on account of some change in the tissues there. 



This is not the place to consider the pathology of gout, nor to enter into 

 any discussion of the various theories concerning it. We can only attempt 



1 Wiener klin. Rundschau: 10, Nos. 1 and 2, pp. 3 and 21 (1896). For further liter- 

 ature see H. Wiener: Ergeb. Physiol. (Asher and Spiro) Jg. 2, 1 Abt., p. 377 (1903). 



