1866.] Mr. Schunck on Oxalurate of Ammonia in Urine, 259 



that of urine itself. The filtered alcoholic liquid is evaporated, and the 

 residue is treated with water, which leaves undissolved a quantity of 

 brownish-yellow fatty matter. This, after being purified m the manner 

 described by the author, is found to consist principally of a fatty acid, 

 having the properties characteristic of the group to which palmitic and 

 stearic acid belong. The acid is white, crystalhne, has a pearly lustre, 

 melts at 54°-3 C, volatihzes unchanged when heated, and is insoluble in 

 water but easily soluble in alcohol and ether. It is soluble in caustic 

 potash and soda-lye, in aqueous ammonia, and in solutions of carbonate of 

 potash and carbonate of soda. The solutions froth on being boiled like 

 ordinary soap and water. The potash compound is obtained from the 

 watery solution in the form of small pearly scales, and from an alcoholic 

 solution in prismatic crystals. The soda-compound separates from a 

 boiling-hot solution on cooling as a thick, white, amorphous soap, a very 

 small quantity of which is sufficient to cause the liquid to gelatinize. The 

 watery solution of either of these compounds gives white curd-like preci- 

 pitates with salts of barium, calcium, lead, and silver. The quantity of the 

 acid obtained in the author's experiments was too inconsiderable to enable 

 him to determine its composition and atomic weight, and it therefore 

 remains uncertain whether it is identical with any of the known fatty acids 

 or not. The author inclines to the opinion that it is a mixture of stearic 

 and palmitic acid, which according to modern investigations constitute 

 together what was formerly called margaric acid. The author does not 

 venture to assert that it forms a normal constituent of the healthy secretion, 

 though the urine employed in his experiments in no case exhibited any- 

 thing peculiar. The experiments described do not throw any light on the 

 question how this acid, which belongs to a class of substances almost inso- 

 luble in water, comes to be dissolved in a liquid like urine, which is itself 

 usually acid. 



V. On Oxalurate of Ammonia as a Constituent of Human Urine.^' 

 By E. Schunck, F.H.S. Eeceived November 15, 1866. 



(Abstract.) 



When ordinary healthy urine is passed through animal charcoal in the 

 manner described in the preceding paper, several organic substances are 

 separated and absorbed by the charcoal in addition to the fatty acid there 

 referred to. The liquid obtained by treating the charcoal with boihng 

 alcohol having been evaporated, the residue is treated with water, which 

 leaves the fatty acid undissolved. The filtered liquid yields on evapora- 

 tion a quantity of crystals, which, after being purified in the manner 

 described by the author, are found to have the properties and composition 

 of oxalurate of ammonia. The watery solution of the substance gives 

 with acids a white crystalline precipitate of oxaluric acid ; with nitrate of 

 silver it produces a precipitate which dissolves without change in boiling 



