THE KIDNEYS SECRETION OF URINE. 505 



but in prisoners without, variation of food, with spare systems, and with in- 

 crease in the tieccs, there was a decrease. Similar results were obtained by 

 Voit, 1 who, in consequence of the very small differences that occurred in the 

 quantities of urea eliminated in fasting animals (Dogs) with and without 

 work, believed that such slight increase of urea as really occurs after severe 

 labor, is due to increased thirst and iugestion of water, together with in- 

 creased rapidity of the movements of the heart and lungs. Lehmann's 2 ex- 

 periments also showed that no increase of urea took place in those engaged 

 in active exercise. In 1866 an important experiment bearing on this point 

 was made by MM. Fick and Wisliceuus. 3 These obervers investigated the 

 changes occurring in the elimination of Nitrogen by the Urine during the 

 ascent of the Faulhorn, one of the peaks of the Swiss Alps, and about 6500 

 feet in height. They took no albuminous food for seventeen hours previ- 

 ously, nor during the ascent, which occupied eight hours, nor for six hours 

 after, their diet consisting of biscuits of starch, fat, and sugar. The exam- 

 ination of the urine gave the following results : 



The average quantity of Nitrogen 

 excreted per hour was, by 



1. Urine of the night previous to the ascent a period Fick. Wislicenus. 



of 12 hours, 0.63 gramme. 0.61 gramme. 



2. Urine of the period of ascent 8 hours and 10 min- 



utes, 041 " 0.39 " 



3. Urine excreted for 6 hours after the ascent, . . 0.40 " 0.40 " 



4. Urine of the night following the ascent, after a 



good meal had been taken 10^ hours, . . 0.45 " 051 " 



Here there was evidently a decrease in the excretion of nitrogen during 

 and after exercise, but it must be remembered that no nitrogenous food was 

 consumed. Very similar results were obtained by Professor Haughton, 4 who 

 found that with about five miles of daily walk the amount of urea eliminated 

 was 501.28 grains per diem, whilst when the exercise was increased to 20.74 

 miles of horizontal walk for five consecutive days, the amount of urea was 

 501.16 grains; actually less than the previous average. Two still more com- 

 plete series of experiments have been conducted by Professor Parkes 5 on 

 two soldiers, in the first series of which he investigated the elimination of 

 nitrogen by the kidneys and intestines, during rest and exercise, on a diet 

 without nitrogen; whilst in the second series the men were placed on a regu- 

 lated diet of nitrogen. In the first series of experiments the men were kept 

 fora first period of six days on ordinary diet and occupation, in order to de- 

 termine the conditions present in perfect health, and to serve as a ground of 

 comparison. Then for a second period of two clays' duration the men were kept 

 on a non-nitrogenous diet and remained at rest. Under these circumstances 

 the urea fell from 35 grammes (which was about the usual daily amount 

 with ordinary diet), to 16.7 in one man, and in the other from 26 to 15 

 grammes, or in both to about one-half its ordinary amount. During the 

 third period of four days the mea returned to their usual diet and occupation, 

 by which time they were considered to have regained their ordinary condi- 

 tion, and the quantity of urea excreted rose to its ordinary amount. Dur- 

 ing the fourth period of two days the men were again placed on non-nitro- 

 genous diet, but on this occasion were made to take severe exercise ; walk- 

 ing on the first day 23.76 miles, and on the second day 32.78 miles. It was 

 found that during the first thirty-six hours there was a decrease; but in the 



1 Henle and Meissner, 1860, p. 373. 



2 Archiv des Vereins fur Wissenschaft. Heilkunde, vol. iv, p. 484, 1860. 



3 Lond. Phil. Mag., 1866, p. 485. 4 Lecture, Brit. Med. Assoc., 1868. 

 5 Proceed. Pvoy. Soc., Nos. 89, 94, 1867. 



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