IN THE UKDsE. 225 



the proportion of the nitrogenized constituents of the urine, 

 particularly the urea. On a non-nitrogenized diet, the pro- 

 portion of urea was found to be diminished more than one- 

 half. The results of the experiments of Lehmann are so 

 striking that we quote them in full : 



" My experiments show that the amount of urea which 

 is excreted is extremely dependent on the nature of the 

 food which has been previously taken. On a purely animal 

 diet, or on food very rich in nitrogen, there were often two- 

 fifths more urea excreted than on a mixed diet ; while, on a 

 mixed diet, there was almost one-third more than on a purely 

 vegetable diet ; while, finally, on a non-nitrogenous diet, the 

 amount of urea was less than half the quantity excreted 

 during an ordinary mixed diet. 



" In my experiments on the influence of various kinds of 

 food on the animal organism, and especially on the urine, I 

 arrived at the above results, which in mean numbers may be 

 expressed as follows : On a well-regulated mixed diet I dis- 

 charged, in twenty-four hours, 32*5 grammes of urea (I give 

 the mean of fifteen observations) ; on a purely animal diet, 

 53*2 grammes (the mean of twelve observations) ; on a vege- 

 table diet, 22*5 grammes (the mean of twelve observations) ; 

 and on a non-nitrogenous diet, 15 '4 grammes (the mean of 

 three observations)." 1 



With regard to the influence of food upon the inorganic 

 constituents of the urine, it may be stated in general terms 

 that the ingest ion of mineral substances increases their pro- 

 portion in the excretions. "We have already alluded to this 

 fact in treating of the different inorganic salts. 



There are certain articles which, when taken into the 

 system, the diet being regular, seem to retard the process of 



1 LEHMAXX, Physiological Chemistry, Philadelphia, 1855, vol. L, pp. 150, 151. 



These results were fully confirmed in the very interesting experiments of 

 Prof. Hammond upon the nutritive value of albumen, starch, and gum, when 

 singly and exclusively used as food ( Transactions of the American Medical As- 

 sociation^ Philadelphia, 1857, vol. x., p. 513, et seq.). 

 15 



