PROPERTIES AND REACTIONS OF URIC ACID. 707 



ASCOLI, IZAR, BEZZOLA and PRETI x have studied the remarkable ability of 

 the liver of destroying uric acid in the blood by transfusing the arterial blood 

 through this organ and on transfusing the blood, saturated with C0 2 , they have 

 regenerated the uric acid. It is not known what becomes of the uric acid in 

 these cases and from what substance the regeneration occurs. PRETI v has shown 

 that in the regeneration a combined action of an enzyme in the blood with a 

 co-enzyme of the liver, takes place. 



From this power of the various organs of destroying uric acid it 

 follows that the quantity of uric acid eliminated is not a sure indication 

 of the amount of the acid formed. We must, therefore, admit that a 

 part of the uric acid formed in the body is destroyed in a manner similar 

 to that introduced from without. BURIAN and ScnuR 2 have indeed 

 suggested a factor, the so-called " integral factor," with which the quan- 

 tity of uric acid eliminated in the twenty-four hours must be multiplied 

 in order to find the quantity of uric acid formed during this time. Such 

 calculations are necessarily very uncertain and are for the present not 

 admissible. 



Properties and Reactions of Uric Acid. Pure uric acid is a white, 

 odorless, and tasteless powder consisting of very small rhombic prisms 

 or plates. Impure uric acid is easily obtained as somewhat larger, 

 colored crystals. 



In rapid crystallization, small, thin, four-sided, apparently colorless, 

 rhombic prisms are formed, which can be seen only by the aid of the 

 microscope, and these sometimes appear as spools because of the round- 

 ing of their obtuse angles. The plates are sometimes six-sided, irregularly 

 developed; in other cases they are rectangular with partly straight and 

 partly jagged sides; and in other cases they show still more irregular 

 forms, the so-called dumb-bells, etc. In slow crystallization, as when 

 the urine deposits a sediment or when treated with acid, large, invariably 

 colored crystals separate. Examined with the microscope these crystals 

 always appear yellow or yellowish brown in color. The most common 

 type is the whetstone shape, formed by the rounding off of the obtuse 

 angles of the rhombic plate. The whetstones are generally connected, 

 two or more crossing each other. Besides these forms, rosettes of pris- 

 matic crystals, irregular crosses, brown-colored rough masses of broken- 

 up crystals and prisms occur, as well as other forms. 



Uric acid is insoluble in alcohol and ether; it is rather easily soluble 

 in boiling glycerin, but very insoluble in cold water, in 39480 parts at 

 18 C. (His and PAUL), and in 15505 parts at 37 (GUDZENT). At 

 this temperature, according to His and PAUL, 9.5 per cent of the uric 

 acid is dissociated in the saturated solution. Because of the reduction 



1 See Zeitschr. f . physiol. Chem., 58, 62, 64 and 65. 



2 Pfluger's Arch., 87. 



