436 URINE* 



determining the quantity of solid constituents and water contained 

 in this fluid. It was supposed that the residue of the urine might 

 readily be determined from its specific gravity, and for this pur- 

 pose Fz. Simon,* Becquerel,f and G. BirdJ, have attempted to 

 establish formulae from which, when the specific gravity was given, 

 the solid residue of the urine might be determined. The complete 

 inapplicability of such formulae, which I have shown by my own 

 experiments, has recently been most completely demonstrated in 

 a large number of investigations made by Chambert || on the urine 

 of healthy persons. These experiments prove that there does not 

 even exist any definite proportion between the quantity of salts 

 in the urine and its density, and much less that any such con- 

 nection exists between the organic matters and the density of 

 the fluid. A comparison of the numbers yielded by the formulae 

 of these three observers will suffice to show the remarkable 

 differences in the results. These differences are clearly exhibited 

 by the following simple illustrations ; thus, for the urine whose 

 specific gravity is 1*010, Becquerel gives 1*650 J, Simon l'927{fj 

 and Bird 2'327-g- ; for a specific gravity of T020, the first gives 

 only 3*300^ the second 4'109-g-, and the last 4*659, &c. 

 If this enormous difference in the results depend upon the 

 different methods adopted by the several observers for the deter- 

 mination of the specific gravity as well as of the solid residue, 

 it is evident from BecquerePs tables, in which the specific gravity 

 is only increased about roWth part and the urinary residue about 

 0*165-, that a progression which is so much at variance with 

 all the laws of physics cannot be correct. It would be necessary 

 to expound the principles of physics, were we to attempt, in the 

 present place, to explain why two or three kinds of urine may have 

 the same specific gravity, and yet differ in the quantities of their 

 solid constituents, and why, conversely, samples of urine which 

 contain similar quantities of solid constituents, might yet differ 

 so considerably in density. In order, however, fully to show 

 the impracticability of this method, we need only refer to the 

 remarks made at p. 4, in reference to the determination of the 

 specific gravity as a means of controlling the chemical analysis. 

 It is obvious, from Schmidt's positive investigations, that a definite 



* Beitriige z. med. Ch. u. Mikrosk. Bd. 1, S. 77 u. 143. 



f Semeiotique des urines, &c. P. 33. 



J London Medical Gazette. New Ser. Vol. 1, p. 138. 



Schn idt's Jalirb. Bd.47, S. 5. 



II Becueil des Me'moirea dc uie'd. et pharm. milit. T. 58, p. 358. 



