484 



Mr. W. North. The Influence of 



P 2 5 ingested July 6 to July 8 11*61 grams. 



P 2 5 excreted July 6 to July 8 8*25 



Difference 3*36 „ 



P 2 6 ingested July 9 to July 12 15*48 



P 2 5 excreted July 9 to July 12 14*08 „ 



Difference . ... 1*40 ,, 



i.e., the work consumed 1*96 grams of the balance accumulated in the 



three days which preceded it. 



The Sulphuric Acid. — A daily increase of 0*25 gram followed the 



work. Reference to the tables shows that the daily increase was — 



In Experiment I 0*24 gram. 



In Experiment II '. . 0*23 „ 



In Part I, Experiment III . . 0*25 „ 



figures hardly to be explained as the result of accident. 



2nd Period. 



The period " before the work " is in this case only one of com- 

 parative rest, because it includes the work done on July 9th. 



The Nitrogen. — Despite the fact that July 9th was a day of exercise, 

 and that a considerable increase in the nitrogen discharge then 

 occurred, the daily difference between the nitrogen discharge before 

 the work of July 13th and that of the period after it is no less than 

 5*68 grams, or a total excess on the average before the work of 

 22*72 grams, and this great increase notwithstanding comparison ot* 

 the ingesta and excreta from July 6th to July 16th, both inclusive, 

 shows a balance in favour of the ingesta of 6*30 grams. The figures 

 of Table E indicate, however, that the drain on the store was hardly 

 over when the fast of July 17th began. I regret exceedingly that I 

 did not continue the observations for three or four days before fast- 

 ing, as it would have afforded an excellent opportunity for observing 

 the retention of nitrogen in the body, which seems to be the natural 

 consequence of a previous excessive discharge. Even if we take the 

 day of fast into our calculations, it leaves only 3*93 grams of nitrogen 

 to be accounted for, which may, I think, be fairly disposed of as a 

 portion of a previously existing reserve. 



The Phosphoric Acid. — Over the whole period, July 6th to July 16th 

 inclusive, there is a balance of 1*24 grams not accounted for in the 

 excreta, and even if we include the day of fast, the ingesta and excreta 

 practically exactly balance one another. There is, however, no doubt 

 whatever in this experiment, that the severe labour produced a very 

 marked increase in the phosphoric anhydride excreted, not only on 

 the day of work but for two or three days after. 



The sulphuric acid, like the phosphoric acid, was nearly doubled on 

 the day of work, and very markedly increased for the three succeeding 

 days. 



