354 



For the information of such of my readers, as may not 

 be of the medical profession, I must here observe, that 

 physicians distinguish two kinds of urine: the one ren- 

 dered immediately after meals, and much dilution^ before 

 the process of digestion, or state of sleep can take place; 

 always more or less limpid; beings comparatively less charg- 

 ed with the natural component parts of urine, (the uree, 

 or extractive colouring matter, in particular,) and called 

 urina potus, to distinguish it from the urina sanguinis, ren- 

 dered, many hours after meals and sleep, the taking no 

 more than a necessary quantity of liquids, and contain- 

 ing the usual proportion of saline, and other ingredients; 

 more especially the uree, to which it owes its natural ci- 

 trine colour. 



This last, therefore, was that employed in the follow- 

 ing experiments, if not otherwise specified: Avith the 

 chemical history of which I must suppose gentlemen of 

 the profession now tolerably Avell acquainted; being so 

 fully and accurately detailed, in the tenth volume of the 

 Connoissances Chimiques. 



Having, in the preceding pages, insisted so much on 

 the acids, and acescent drinks, as occasional causes of 

 these complaints, the first object seemed to be, to ascer- 

 tain whether the urine of those most subject to them, or 

 actually labouring under them, was more relatively acid. 

 We have already seen, from a register of these patients, 

 k.ept for forty years in the hospital of Luneville, that the 

 early period of life, from two to six years of age inclusive, 



i3 



