OF ARTS AND SCIENCES. 265 



By the long-continued action of nitric acid upon dimethyluric acid 

 methylparaban is formed. After boiling with nitric acid of sp. gr. 1.3 

 till a drop of the solution gave no coloration with ammonia, the 

 solution was evaporated on the water-bath until the excess of acid was 

 driven off and the sirupy residue diluted with a little water. The 

 crystals which separated were pressed with paper and recrystallized 

 from hot water. 



Thus prepared the substance melted at 149°, sublimed slowly at 

 100°, readily at higher temperatures, and gave on analysis the per- 

 centages corresponding to methylparaban. 



0.2838 gr. gave 0.3886 gr. C0 2 and 0.0879 gr. H 3 0. 



By the oxidation of dimethyluric acid with potassic permanganate 

 in alkaline solution, we have been unable to prepare the correspond- 

 ing dimethyhillantoin. The acid either undergoes a more radical 

 decomposition, or more probably the assimilation of water takes place 

 more readily than in case of allantoin or even methylallantoin and 

 the dimethylallantoic acid results. 



"VVe made several attempts to isolate from the uncrystallizable 

 product of the oxidation various salts of the dimethylallantoic acid, 

 but found them so uninviting in their character, that we could hardly 

 hope to effect their purification. 



Since considerable time must of necessity elapse before further 

 results can be obtained in this investigation, it may not be out- of 

 place to call attention to one inference concerning the structure of 

 uric acid which may fairly be drawn from the facts thus far estab- 

 lished. 



It has been shown that the two hydrogen atoms of uric acid which 

 are replaced in the formation of salts are directly connected with two 

 different nitrogen atoms ; furthermore, when methyl groups are 

 introduced in the place of these hydrogen atoms, that two other hydro- 

 gen atoms may then be replaced by metals. The only simple expla- 

 nation of this behavior would seem to be that the four hydrogen atoms 

 of uric acid are attached to four different nitrogen atoms, and that 

 only two of these hydrogen atoms can be replaced at the same time 



