1880.] Of Nitrogen excreted in the Urine by Man at Rest. 447 



II. Upon a strictly non-nitrogenous diet the observations are not 

 numerous : — 



Ranke found 8 grms.,* 

 and Yon Franque 7*5 grms. 



III. Professor Playfair attacked the question from another side, 

 by collecting from various sources the minimum diets upon which 

 man could live, and to which he gave the name of subsistence diets, 

 and by calculation the amount of nitrogen contained in them. This 

 method gave him as a mean 9"2 grms., but his patients were none 

 of them at absolute rest, but were performing during the day a certain 

 amount of work.f Edward Smith in the same way by calculation 

 from the diets of the spinners during the cotton famine found a some- 

 what larger amount of nitrogen (12 grms.), % which agrees with the 

 amount of nitrogen contained in Play fair's second class of small diets, 

 but in all these cases the effect of muscular exertion is not eliminated. 



TV. Unruh gives a series of three observations upon hospital patients 

 kept at rest, and placed upon a restricted diet. Unfortunately he 

 gives little description of the diet, except that it was fever diet, and 

 consisted of beef-tea or broth, with an egg or two. 



In the first, a case of cancerous obstruction, the amount of nitrogen 

 was 8 grms. (17*5 urea). But this case is not altogether satisfactory 

 from the amount of wasting accompanying this disease. 



The other two were cases of syphilis placed upon fever diet, and 

 kept at rest for the sake of the experiments ; the first passed 8' 6 

 grms. (18'6 urea), the second 7'5 grms. (16*2 urea). 



The mean of these three cases is 8 grms. (17'5 urea). 



The general results of the various series of observations may be 

 roughly tabulated thus : — 



I. Starvation. 8 grms. 



II. Non-nitrogenous food. 8 grms. 



III. Subsistence diet. 9 grms. 



IV. Insufficient diet. 8 grms. 



V. Clinical equilibrium. 8 grms. 



A remarkable coincidence, considering the variety of the methods 

 employed, and the different conditions under which the determinations 

 were made. 



We may therefore conclude that the minimum amount of nitrogen 

 excreted by a healthy adult man is on the average 8 grms. in the 24 

 hours, this being equivalent to 17*5 grms., or to 260 grains of urea. 



* Ranke {ut supra) » 



f " On the Food of Man in relation to his useful Work." Edinb., 1865. 

 X " Influence of Food," 1860. 



