INGKEDiENTS OF THE UEINE. 



381 



tending over comparatively long periods, both of exercise and rest, the 

 diet at the same time remaining unchanged in its general characters. 



The pedestrian was under observation for fifteen days ; namely, five 

 days previous to the walk, five days during its continuance, and five 

 days immediately afterward. For the period preceding the walk, the 

 average exercise was about eight miles per day ; during the walk it was 

 nearly sixty-four miles per day, and for the period subsequent to the 

 walk, it was a little over two miles per day. The results obtained 

 during the three peri9ds showed, accordingly, the normal amount of 

 urea excreted by the pedestrian under ordinary conditions, the amount 

 discharged during an unusual and nearly continuous muscular exertion, 

 and the subsequent effects of the exertion on the general condition of 

 the system. 



The nitrogenous ingredients of the food, during all three periods, 

 were also recorded, so that the influence of the food itself on the amount 

 of urea may be estimated at the same time with that of the muscular 

 exertion. 



The following table gives the main result of these experiments, so 

 far as they are connected with the present subject : 



It is evident, therefore, that during the time of unusual muscular 

 exertion the daily quantity of urea was increased by nearly fifteen per 

 cent, over that of the previous ordinary condition, the nitrogenous ele- 

 ments of the food being at the same time considerably diminished ; and 

 that, during the period of exertion, the total quantity of nitrogen dis- 

 charged by the urea and feces combined was nearly seventy-five per 

 cent, greater than that introduced with the food, while in both the pre- 

 vious and subsequent periods it was from about four and a half to eight 

 per cent. less. During the period of exertion there was a loss of nearly 

 three and a half pounds of bodily weight, and an increase of similar 

 amount during the subsequent period of rest. The author fairly explains 

 the above loss of weight by the disintegration of muscular tissue; and 

 the subsequent increase, by a retention of nitrogenous constituents in 

 the body, to repair the waste thus produced. 



"During the five days of the walk, 1 Mr. Weston consumed in all 

 1173.80 grains of nitrogen in his food. During the same period he 



New York Medical Journal, June, 1871, p. 669. 



