158 THE JOURNAIy OF PHARMACOLOGY. 



proteids, these in turn constituting the chief constituent of the nuclei of 

 most cells. Hence any condition, pathological or otherwise which is ac- 

 companied by an increase of cells (such as the white blood cells for in- 

 stance) causes an increased excretion of uric acid. On the other hand, 

 any condition which results in a diminution of these cells causes a decreased 

 excretion of uric acid. In the case of uric acid an increased quantity is of 

 greater pathological significance than a diminished quantity. In the case 

 of urea the reverse is true. The chief danger resulting from the excretion 

 of an increased quantity of uric acid is its tendency to form deposits, and 

 at times calculi. This is particularly true in the case of some individuals. 

 This condition is known as lithemia or uric acid diathesis. The disease 

 known as leukemia is accompanied by an increased excretion of uric acid, 

 as much as 4-6 grammes daily being excreted. The number of white 

 blood cells is greatly increased in case of this disease, and this fact no 

 doubt accounts for the excessive quantity of uric acid excreted. Contrary 

 to general opinion the quantity of uric acid eliminated by way of the 

 urine is not increased in every case of rheumatism and gout, in fact in 

 certain cases the quantity may be diminished or even suppressed owing 

 to the deposition of uric acid and water in the various joints of the body. 

 Many nervous disorders cause an increased excretion. The administration 

 of certain drugs likewise causes an increased excretion, among others such 

 drugs as pilocarpine and sodium salicylate may be named. The fact that 

 the latter drug causes an increased excretion of uric acid has been ques- 

 tioned, but evidence that it does cause an increase preponderates. A 

 diminished excretion of uric acid is noted in cases of diabetes mellitus, 

 also after the ingestion of many drugs, such as quinine, caffeine, antipyrine, 

 and iron and lead salts. Our present knowledge leads us to believe that 

 the spleen is the organ which is chiefly responsible for the formation of 

 uric acid, and that this acid represents the nitrogenous waste product 

 from the decomposition of nucleins. These bodies therefore must be con- 

 sidered as the mother substance of uric acid as well as of the xanthin 



bases. 



Properties and Tests. 



Pure uric acid occurs in the form of a white powder, consisting of trans- 

 parent rhombic plates. From acid urine or from urine to which acids 

 have been added, it crystallizes in various forms, and is almost invariably 

 colored. The chief form is whet-stone or wedge-shaped, often, however, 

 it is found in the shape of a cross, or as interlaced needles. Barrel-shaped 

 or dumb-bell shaped crystals are also of frequent occurrence. Uric acid is 

 difficultly soluble in water (1-14,000 cold, 1-1,800 hot). In urine it is 

 found chiefly in the form of sodium urate. It is a dibasic acid, and as 

 such forms two classes of salts, neutral urates, which are freely soluble in 

 water, and acid urates which are but sparingly soluble. 



