382 THE POPULAR SCIENCE MONTHLY. 



they were enabled to estimate what relation the albuminoid decompo- 

 sition bore to the amount necessary to supply the power for the ascent. 

 By this method they demonstrated that the whole amount of albumi- 

 noid material decomposed during the ascent, even if completely oxid- 

 ized to carbonic acid, water, and nitrogen (instead of yielding its nitro- 

 gen in the form of urea, as is actually the case), would produce less than 

 half the force necessary to raise their bodies through the vertical height 

 to which they ascended. Thus it is shown that the amount of force 

 represented by the actual decomposition of albuminoids during work 

 is by no means adequate to account for the work done, even supposing 

 that all the nitrogenous material decomposed in the body went for that 

 purpose, and that no other muscular work were performed during the 

 ascent than the mere lifting of such a weight to the given height. 

 Both these suppositions are evidently incorrect, as the nitrogen is elimi- 

 nated in almost equal quantities when no voluntary muscular action is 

 exerted, and the muscular work, voluntary and involuntary (lungs, 

 heart, etc.), on such a trip, would evidently far exceed that necessary 

 for the simple elevation of a dead weight to a specified height. 



Experiments conducted by Dr. Parkes on two soldiers proved that 

 a small increase of nitrogen elimination was produced, and also, that 

 this increased elimination of nitrogen may extend for many days after 

 the exercise has ceased. 



Dr. Austin Flint, Jr., in an elaborate and thorough investigation on 

 the pedestrian Weston, found a decided increase in the nitrogen elimi- 

 nated during work ; also, a decided increase in the ratio of nitrogen 

 eliminated to that taken in with the food. The value of his results is 

 somewhat impaired for our present purpose, in so far as they relate to 

 the influence of muscular exertion simply, because the condition of the 

 subject during the working period was not such as was favorable for 

 a fair test. His appetite fell off ; he slept poorly ; was extremely nerv- 

 ous and irritable much of the time ; became at times much exhausted 

 and prostrated even to nausea. When the influence of the nervous 

 state and of an exhausted condition on the functions is taken into ac- 

 count, it will be evident that deductions as to the effect of muscular 

 exertion alone would in this instance be open to doubt. Dr. Pavy's 

 experiments on the same pedestrian indicated also an increase in the 

 nitrogen elimination, but only a slight increase as compared with 

 Dr. Flint's results. 



What, then, seems tolerably certain is, that muscular exertion in- 

 creases the nitrogen elimination but slightly, and perhaps only very 

 slightly, so long as the muscular system is moderately exercised and not 

 overtaxed. And, indeed, the pertinent question here would seem to be, 

 " Is the normal muscular action accompanied with any elimination of 

 nitrogen showing a decided relation of the work done to the nitrogen 

 eliminated ? " and not " Is the excessive and exhaustive exertion of the 

 muscles accompanied with any increase of nitrogen elimination ? " 



