76 PHOSPHATES ABOUND IN 



XV. A comparison of the urine of the carnivora 

 with that of the graminivora shows very clearly, that 

 the process of metamorphosis in the tissues is differ- 

 ent, both in form and in rapidity, in the two classes 

 of animals. 



The urine of carnivorous animals is acid, and con- 

 tains alkaline bases, united with uric, phosphoric, and 

 sulphuric acids. We know perfectly the source of the 

 two latter acids. All the tissues, with the exception of 

 cellular tissue and membrane, contain phosphoric acid 

 and sulphur, which latter element is converted into sul- 

 phuric acid by the oxygen of the arterial blood. In the 

 various fluids of the body there are only traces of phos- 

 phates or sulphates, except in the urine, where both are 

 found in abundance. It is plain that they are derived 

 from the metamorphosed tissues ; they enter into the 

 venous blood in the form of soluble salts, and are separ- 

 ated from it in its passage through the kidneys. 



The urine of the graminivora is alkaline ; it contains 

 alkaline carbonates in abundance, and so small a portion 

 of alkaline phosphates as to have been overlooked by 

 most observers. * 



The deficiency, or absence of alkaline phosphates in 



* In a series of observations, continued daily during ninety-six 

 days, human urine was found to be, on four occasions, feebly acid in 

 the morning. In almost every observation it was found neutral, 

 or very feebly alkaline. Lactate of urea could never be detected 

 in it. J. L. 



The translator would add to this note, that in numerous experi- 

 ments made by him, the process given by Messrs. Cap and Henry 

 for extracting lactate of urea from human urine, yielded invariably 

 pure urea. W. G. 



