Bodily Labour upon the Discharge of Nitrogen. 



491 



Experiment, February hth to March 3rd, 1883. 



This experiment was conducted entirely for the purpose of deter- 

 mining the amount of the nitrogenous reserve, of the existence of 

 which, in one sense or another, I now feel thoroughly assured. 



The plan adopted was, after having lived on the experimental diet 

 for some time, to abstain from food once or twice, in order to see 

 whether the amount of nitrogen discharged during a twenty-four 

 hours' fast was much influenced by the amount of food which had 

 been taken for some days previously. I think I may say in start- 

 ing, that the result was a negative one, that is to say, that the 

 amount discharged in a twenty-four hours' fast seems to be prac- 

 tically a constant under ordinary circumstances. 



It further seemed to me probable, or at all events possible, that as 

 now nearly six years have elapsed since the original observations 

 were made which determined my experimental diet, I might be 

 habitually taking more or less food per diem than I did six years ago. 



In order to test this, from February 6th to February 13th inclu- 

 sive I collected my excreta, whilst living upon such a diet as I have 

 been accustomed to during that period, without any regard to experi- 

 mental considerations. I ate, drank, slept, and worked as though no 

 experiment were in progress, and in order to avoid any possible 

 influence which such observations might have had upon my mode of 

 life, I abstained from noticing the variations of body- weight, tempera- 

 ture, nitrogen discharge, &c, as I have found that when I am obliged 

 to make such observations myself, I cannot avoid the effect of con- 

 sideration of them upon my daily life. For instance, I feel quite 

 certain that had I known that on any particular day the nitrogen 

 discharge was higher or lower than I might have expected, the know- 

 ledge of it would unquestionably have affected the amount of food I 

 should have taken on the following day. This may seem a somewhat 

 extraordinary admission to make, but nevertheless I am convinced of 

 its truth. During the whole of this first period, therefore, I was 

 careful not to inform myself of the results of the analyses. On 

 February 14th and 15th I abstained from all food whatsoever. On 

 February 16th I began the ordinary experimental diet, and continued 

 it until February 26th. On February 27th I again abstained from all 

 food, returning on the 28th to my diet, which was continued until 

 March 3rd. This experiment then naturally divides itself into two 

 parts, the period of ordinary diet and the period of experimental 

 diet, and we have to consider the effect of the fasting in each case. 



Inspection of the figures, particularly those which show the daily 

 discharge of nitrogen by the urine, suffices to demonstrate the great 

 similarity which exists between my ordinary food and my experi- 

 mental diet. 



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