Influence of Labour upon the Discharge of Nitrogen, 413 



"The Influence of Bodily Labour upon the Discharge of 

 Nitrogen." By W. North, B.A., F.C.S. Communicated 

 by J. Burdon Sanderson, F.R.S. Received October 29, 

 1883. Read November 15. 



[Plates 5—10..] 



As in the experimental researches previously published on the sub- 

 ject of the present paper, the methods employed have been for the 

 most part entirely different from those which I have found best 

 adapted to the purpose, I have after much consideration judged it 

 inexpedient to lengthen an already long communication by giving an 

 account of them. 



The scope of my inquiry has been strictly limited to one question, 

 viz., that of the influence of labour in modifying the normal relation 

 between food and excreta. I have made no attempt to investigate the 

 mode in which nitrogenous products came into existence in the 

 organism. 



The only published experiments of any importance which bear 

 strictly on the subject of inquiry are those of Dr. Parkes,* contributed 

 to the Royal Society in 1867 and 1871, and those of Dr. Austin Flint, 

 on the pedestrian Weston, 1871. f The results of these two investi- 

 gations were as follows : — 



Dr. Parkes found that during or immediately after severe labour, 

 the discharge of nitrogen was more or less increased ; the increase, 

 however, was so inconsiderable that it might well be questioned 

 whether it could not be accounted for as dependent on the more 

 perfect absorption of food, for although the diet of the soldiers 

 experimented upon was carefully regulated, and the nitrogen it con- 

 tained determined by analysis, with the result that before work the 

 quantity of nitrogen taken in considerably exceeded the quantity 

 discharged, the two became practically equal during the work period, 

 consequently if the whole period of observation is taken into account, 

 the nitrogen discharged is found to be more than balanced by that of 

 the food. 



Dr. Austin Flint, on the other hand, found that over the period of 

 work the increase of discharge was so large that no such explana- 

 tion appeared to him admissible; if, however, comparison is made 

 of the intake with the output of nitrogen during the whole time of 

 observation, comprising the three periods of five days each before, 

 during, and after labour, it is found that the two are unequal, the 



* "On the Elimination of Nitrogen during Rest and Exercise on a Regulated 

 Diet," "Proc. Roy. Soc," vol. 15, p. 339, vol. 16, p. 44, 1867 ; vol. 20, p. 402, 1871. 

 f " New York Medical Journal," June 1871, p. 609. 



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