The Urine. 203 



176 ozs. of hippuric acid per diem ; fed on oats and a 

 moderate amount of hay l oz. to | oz. per diem is yielded. 

 This was the mean amount I found in horses fed on the 

 same diet. 



Lie big, many years ago, started a theory that benzoic 

 acid was found in the urine of working horses, and hippuric 

 acid in the urine of those at rest ; I have endeavoured to 

 find out what truth there was in the statement. My 

 observations showed that hippuric acid is generally found 

 in the urine of working horses, and seldom found in the 

 urine of horses at rest — in fact, the reverse of Liebig's 

 theory. Hippuric acid is rarely to be found in urine 24 

 hours old ; in fifty-four specimens I only found it eight 

 times ; this is due to its fermentative decomposition. 



Benzoic Acid is the antecedent of hippuric. As just 

 mentioned, it is derived from the benzoic-acid-forming 

 substances in vegetable food. The amount found in the 

 urine of horses at rest is about £ oz. per diem. 



Sulphuric Acid exists in the urine in two forms : first, as 

 an inorganic compound; second, as ethereal sulphates. 

 Both are derived from the decomposition of proteids, but 

 the ethereal sulphates or sulphonates are combined in the 

 form of a potash salt with phenol, cresol, catechol (or 

 pyrocatechin), indol, and skatol. 



These ethereal sulphates occupy an important position in 

 the composition of the urine of herbivora, as they are 

 largely derived from the aromatic substances found in their 

 food, or from the splitting up of the complex albumin 

 molecule during pancreatic digestion. In carnivora and 

 omnivora the ethereal sulphates are a measure of the 

 amount of decomposition occurring not only in the proteids 

 of the body, but of active putrefactive changes occurring 

 either in the intestinal canal or outside it, such as in septic 

 and suppurative diseases. This will not hold good for the 

 herbivora, as much of the material excreted does not arise 

 from putrefaction, but is taken iu with the food. 



The union of the ethereal sulphates with the aromatic 

 compounds takes place in the liver. When the phenol 



