1867.] Dr. Parkes on the Elimination of Nitrogen. 



47 





S. 



B. 



Ordinary occupation, ist day 



■ 



o 







j> M 2nd „ 



o 



+ 200 



,» 3i*d „ 



4- 400 



— 500 



j> )» 4th „ 



— 400 



+ 300 





— 500 



— 400 





— 200 



— 100 





+ 200 







„ „ 8th i, 



+ 500 



+ 400 



» >» 9*11 „ 



+ 200 



-|- 100 





— 200 



-{- 200 





— 1500 



— 1400 





— 1000 



— 1000 



Ordinaiy occupation, iith , 



-\- lOCO 



+ 500 





+ 600 



+ 800 





+ 400 



+ 400 





+ 300 



+ 600 



The "Weight in the first period was fairly constant ; but during the rest- 

 period one man lost 1| lb. and one other 1 lb. in weight ; the loss was gra- 

 dual on the two days, wbich was different from the alternations which had 

 gone before; tbe loss was subsequently recovered from at the rate of rather 

 less than J lb. a day until the usual weight was regained on the third 

 and fourth days. As the amount of food ingesta was not less, the loss 

 must have been owing to increase in the egesta. This was certainly an 

 unexpected result, but is yet quite certain. 



The nature of the increase in the egesta will appear presently. I will 

 merely state here that it was not owing to any condition of external 

 temperature or atmospheric humidity acting on the skin or lungs. In 

 the first four days of ordinary occupation the maximum temperature in 

 the shade was 59°, 61°'2, 64°'8, and 65° E., while the mean of the maxi- 

 mum and minimum temperatures of twenty-four hours was 51°-2, 52°-6, 

 50°-2, 54.°-4. In the rest-period of two days the maximum shade tempe- 

 rature was 64° and 68°, and the mean temperature of the days was 54°"5 

 and 58°4. In the after-rest period, when the body was regaining weight 

 on the same diet, the temperature rose greatly, the maximum being 

 74°'8, 81°*6, 75°, and 70°, while the mean of the maximum and minimum 

 was 61°, 66°-3, 62°, and 59°-5. 



It is evident therefore that the weight altered independently of the 

 external temperature ; for there was scarcely any difiference between the 

 first and rest-period, and if any action had been caused it should have 

 gone on in the succeeding hotter days of ordinary exercise during the 

 third period. The air was a little drier during the two days of rest 

 (65*3 per cent, of total humidity) than in the preceding and following 

 periods (72-6 and 72-9) ; but this slight difference had no effect, because 

 on one of the days following the rest the air was both hotter and drier 

 than on one of the rest-days, and yet the body gained weight. 



During the period of exercise both men lost greatly and almost equally 

 in weight, and then during the following period regained it, so that in 

 four days one man had recovered his former weight, and the other man 

 was only ^ lb. short. 



