398 INFLUENCE OF MUSCULAR EXERCISE ON THE URINE. [BOOK 1. 



If now we contrast the experiments of Flint and Pavy 



IU1U ' ^rn 



sions. 



we observe in the first place that both shew an increase 



. of nitrogen eliminated during exercise : the proportion of 

 nitrogen ingested to nitrogen excreted is, during the days before the walk, 



in Flint's case 1 : '8658 



in Pavy's case 1 : '6698 

 while during the walk it is 



in Flint's case 1 : 1439 



in Pavy's case 1 : '7764 



But in the second place, we are struck by the remarkable difference 

 in the degree of the increase. This discrepancy, which has led Prof. Flint 

 into a long discussion of the question of muscular power, it is not necessary 

 to examine fully here. Assuming for the moment that the calculations 

 of both observers are well-founded, it is sufficiently clear that some 

 circumstance must have existed in one or the other experiment to destroy 

 their precise analogy. For example, in Flint's case the food of Weston 

 fell off considerably during the period of exercise ; while in Pavy's it 

 increased. Moreover, in Flint's experiment Weston urged himself to 

 the very extreme of endurance. "The most notable event in the course 

 of the five days' walk was what appeared to be a total collapse of muscu- 

 lar and nervous power. * * * * At 10.30 P.M. on this (the fourth) day, 

 Mr Weston broke down completely. He could not see the track, and 

 was taken staggering to his room, having reached apparently the limit 

 of his endurance. * * * The calculations as well as the general condition 

 of the system, shew that the period had probably arrived when repair of 

 the muscular system had become absolutely necessary 1 ." If we may 

 suppose that over-exertion brings about a condition of muscular tissue in 

 which disintegration proceeds with unusual ease 2 , the very marked increase 

 of urea and uric acid in Prof. Flint's case admits of a simple explanation ; 

 and especially if we may further suppose that over-exertion, in certain 

 extreme cases, leads to the absolute rigor of individual fibres, as it does in 

 the case of muscles out of the body. In this condition the rigid albuminous 

 fibres would rapidly degenerate and serve to increase the common nitro- 

 genous excretions of the body 3 . 



In addition to demonstrating a slight increase of nitrogenous excreta 

 during exercise, Dr Pavy endeavours to shew that the nitrogenous waste 

 during the walking period is wholly incompetent to account for the 

 mechanical work done. His argument is similar to that of Fick and 

 Wislicenus. 



Still more recently W. North 4 in experiments upon him- 



mentsTof " se ^' ^ as arr ^ ve( i a * confirmatory results. He determined the 



W North. urea excreted and, by Payen's Tables, the nitrogen ingested 



during eight days, beginning on Monday, Sept. 3. On 



Monday, Tuesday and Wednesday, nitrogenous food was taken ad libitum: 



1 Flint, Journ. of Anat. and PhysioL, Vol. xn. p. 134. 



2 T. R. Noyes, "Experimental Researches on the excretion of urea." American 

 Journal of the Med. Sci., New Series, Vol. LIV., 1867, p. 354. 



3 Hermann, Stnffwechsel der Muskeln, p. 100. 



4 W. North, " An Account of two Experiments illustrating the effects of Starvation 

 with and without severe Labour, on the Elimination of Urea from the Body." Journal 

 of Physiology (ed. by M. Foster), Vol. I. p. 171. 



