(Jg ON URINE AND ITS ACIDS. 



not the solvent of the phosphate of lime in urine, it must 

 undoubted ly be some other weak acid, and probably an acid 

 of the nature of the vegetable and animal acids. 

 This probably Nothing- in fact proves, that this is not the case. I will 

 a mistake. venture to say farther, that this hypothesis appears to me 

 more admissible than the former: for, to admit the acidu- 

 lous phosphate of lime in urine, we must suppose, that a 

 portion of one of the phosphates of the blood is decomposed 

 in the kidneys, when it reaches them: that the phosphoric 

 acid is free, or at least constitutes an acidulous phosphate 

 with the phosphate of lime, though present with the soda of 

 the blood, and with the base of the phosphate decomposed, 

 both of which appear not to enter into any new combination 

 at the time, and which are taken up with the residuum of the 

 secretion by the venous system, to be returned into the cir- 

 culation. 

 In the living It is true it may be said, that bodies under the influence 



action ma" be °lf ^ e act m a different manner from what they do when de- 

 restrained, pvived of it ; and that consequently decompositions may take 

 place in the animal economy contrary to all that we are ac- 

 quainted with. But, beside that this answer, though accu- 

 rate, proves little in favour of the case in question, it may 

 be employed in a certain degree to retort the argument, as 

 thus: we have no avowed instance of salts being decom- 

 posed in the animal economy so that their alkali and acid re- 

 main present together without combining, while on the other 

 hand it is demonstrated, that animal substances, particularly 

 those that exist in the blood, as the fi brine and albumen, are 

 transformed into some other in passing through this or that 

 organ; thus in the mammary glands they are converted into 

 sugar of milk, and the caseous, butyraceous, and extrac- 

 tive matters; and in the kidneys they form uree, uric acid, 

 and sometimes benzoic acid. Now if they constantly form 

 one of these acids, and sometimes the other likewise, it is 

 possible they may form a third, which combines with the 

 phosphate of lime, and holds it in solution. Such were the 

 reflections that have led me to examine the acid of urine; 

 and I shall proceed to relate the experiments, that I have 

 made to discover its nature* 



After having employed several means, which I shall pase 



over, 



