Bodily Labour upon the Discharge of Nitrogen. 501 



condition, and I shall not be satisfied that this is not the case nntil I 

 have examined the effect of living for several days on a diet whose 

 daily nitrogenous value shall be only 9 grams, the other consti- 

 tuents remaining as far as possible the same. I should expect to find 

 that twenty-four hours' starvation would result in a discharge of a 

 smaller quantity of nitrogen, say 5 grams, which might be found 

 to be tolerably constant under similar conditions. When this had 

 been determined, two or three days of a non-nitrogenous diet would 

 probably suffice to indicate approximately the daily nitrogenous 

 w r aste of the body from other sources than food. We have no infor- 

 mation of any importance as to the minimum of nitrogen required by 

 the body daily in order to maintain it in health, and I feel sure that 

 experiments on the plan indicated would throw considerable light on 

 the subject. 



Conclusion. 



The results which have been now put on record, whilst they con- 

 firm the conclusions of Dr. Parkes, show that the disturbance pro- 

 duced by very severe labour is much more immediate and of much 

 greater intensity than that which Dr. Parkes observed, the expla- 

 nation obviously being that in his experiments the exertion imposed 

 on the soldiers who were made the subjects was inadequate. 



It has been further shown that, just as in Dr. Parkes' experiment 

 on the effect of privation of nitrogenous food, the diminution of the 

 nitrogen stored in the system was followed by retention, i.e., by a 

 state of things in which the intake was greater than the output ; so 

 after the disturbance of the nutrition of the body, which is produced 

 by severe labour, the immediate effect of which is obviously to dimi- 

 nish the store of nitrogenous material in the system, there follows a 

 corresponding diminution of discharge, so that the result is the 

 same, namely, that in Dr. Parkes' words, " an insufficient supply at 

 one time must be subsequently compensated," whether the insuf- 

 ficiency be due either to privation or to exercise. 



A third result of importance is this : that this storage of nitrogen 

 is the expression of a tendency of the organism to economise its 

 resources, which is much more constantly operative than has hitherto 

 been supposed. 



Thus it appears that whenever the subject of experiment was put 

 upon the regulated experimental diet, without the imposition of more 

 exercise than belongs to an ordinary active life, accumulation took place 

 even when the daily supply of nitrogen did not exceed 17*6 grams, 

 an amount which cannot be regarded as more than adequate to the 

 normal requirements of the organism. This tendency to store 

 nitrogen is therefore a normal endowment of the living body, and, 

 if so, the "retention" which follows starvation or exercise must be 



