INORGANIC SALTS. 17 



tained physiological importance is so slight, that it would be 

 out of place to describe them. 



In the preliminary remarks on the urine, it was mentioned 

 that the inorganic salts were amongst the most important 

 constituents of the secretion ; we must now take up their 

 consideration more minutely. The urine of the carnivora 

 contains sulphates, chlorides, and phosphates. The urine of 

 the herbivora contains a large per-centage of carbonates, with 

 some sulphates, and a little chloride of sodium; these salts give 

 to it its alkaline reaction, and constitute the sediment which, 

 as before mentioned, falls when such urine is allowed to rest. 

 The presence of carbonates in the urine of the herbivora is 

 shown by the effervescence which ensues when a strong acid 

 is added to the urine. When we consider the cause of the 

 great differences existing in the salts in the two great orders 

 of ruminantia and carnivora, we find it to consist in the nature 

 of the food. The flesh, blood, and other parts of animals, 

 as pointed out by Liebig, contain no free alkali, for it is in 

 them invariably combined with phosphoric acid. "The acids 

 formed in the organism by the vital process, namely, sulphu- 

 ric acid, hippuric acid, and uric acid, share the alkali amongst 

 them, and this of course gives rise to the liberation of a cer- 

 tain amount of phosphoric acid, or what comes to the same 

 point, to the formation of a certain amount of acid phos- 

 phates of soda, lime, and magnesia. On the other hand, all 

 the vegetable aliments, without exception, contain alkalies in 

 combination with vegetable acids; potatoes, for instance, 

 contain alkaline citrates; turnips, alkaline racemates and 

 oxalates, &c. All these plants yield, upon incineration, 

 more or less strongly alkaline ashes, the bases of which were 

 contained in the living plants, as salts of vegetable acids. "- 

 (Liebig, Lancet, June, 1844.) 



When taken into the system, the organic acids are burned 

 VOL. n. 2 T 



