214 CONJUGATED ACIDS. 



the quantity of uric acid in a specimen of urine, from the formation 

 of a sediment. 



I can fully confirm BecquerePs* observations on this point by 

 my own experience. 



The sediment which is deposited from acid urine in fever, and 

 in almost all diseases accompanied with severe fever, has long been 

 misunderstood in reference to its chemical composition. Originally 

 it was regarded as a precipitate of amorphous uric acid, and subse- 

 quently (and almost to the present time) it was regarded as urate 

 of ammonia. It has, however, been fully demonstrated both by 

 myselff and HeintzJ, that this sediment consists of urate of soda 

 mixed with very small quantities of urate of lime and urate of 

 ammonia. It may be very easily and quickly distinguished from 

 any other urinary sediment, both by the microscope and by the 

 application of a gentle warmth : under the microscope it certainly 

 shows little that is characteristic ; it forms fine granules which are 

 sometimes aggregated in irregular heaps, sometimes conglomerated 

 so as to resemble granular cells, and in some instances uniformly 

 distributed over the field of the microscope : as the characteristic 

 forms of uric acid almost immediately appear on the addition of a 

 stronger acid, it is impossible that it can be confounded with any 

 other urinary sediment. An even more simple method of ascer- 

 taining that this sediment consists of urate of soda, is afforded by 

 the circumstance that it dissolves at 50, so that urine rendered 

 turbid by it, when raised to that temperature, becomes clear and 

 limpid. 



It would be both superfluous and wearisome to recapitulate the 

 arguments adduced by Becquerel, myself, and Heintz, against the 

 opinion of Bird, who maintains that this sediment is always urate 

 of ammonia, as the actual nature of the deposit has been so com- 

 pletely established. I will here only remark that, as I long ago 

 found, and as Liebig has since confirmed, scarcely any ammonia 

 occurs in urine, and that, according to the direct analysis of the 

 sediment made by Heintz, scarcely 1^ of ammonia could be found 

 in it. 



Much has also been written to prove that uric acid does not 

 exist free in the urine, but in a state of combination with alkalies ; 

 but it requires only a moderate knowledge of the properties of uric 



* SeWiotique des Urines, pp. 51 and 249, or pp. 40-50 and 126-180 of the 

 German Translation. 



t Jahresber. d. phys. Ch. 1844. S. 2G. 

 J Muller's Arch. 1845. S. 230-261. 



