1 82 STORKS AGRICULTURAL EXPERIMENT STATION. 



Occupation. — The metabolism experiments were both rest and 

 work experiments. During the period prehminary to the rest 

 experiments the subject was generally engaged in his usual oc- 

 cupation, but avoided muscular exertion, conforming his activ- 

 ities as much as possible to those of the coming calorimeter 

 experiment; during his .sojourn in the respiration chamber he 

 remained as quiet as practicable. In the work experiments 

 the subject spent the preliminary period at his regular occupa- 

 tion, and in addition, walked or rode a bicycle out doors a con- 

 siderable distance each day in pleasant weather, or exercised 

 upon a "home trainer" within doors in stormy weather. 

 During the period within the chamber he spent eight hours 

 each day regularly operating a stationary bicycle arranged as 

 an ergometer. The purpose was to perform a reasonable but 

 not excessive amount of work. In only one experiment was 

 the work at all severe. 



Diet. — The diet provided palatable food materials with as 

 much variety as was consistent with convenience in prepara- 

 tion and accuracy in sampling and analyzing. For the sake of 

 greater accuracy the number of different materials used was 

 somewhat less in the later than in the earlier experiments. 

 The quantities of nutrients in the diet were in general such as 

 to maintain the body nearly in nitrogen and carbon equihbrium 

 under the conditions of the experiment. In a few cases, how- 

 ever, in which the muscular work was considerable the diet 

 was not quite sufficient for body maintenance and there was 

 consequently more or less draft upon the store of body mate- 

 rial. The purpose of the preliminary digestion period was to 

 accustom the subject to the diet and to determine whether 

 under the conditions of the experiment nitrogen equilibrium 

 could be maintained on the diet provided. Any change in diet 

 found necessary or desirable was made during this period; this 

 will explain the slight discrepancies seen in some of the tables 

 between the quantities of food in the preliminary period and in 

 the calorimeter period. 



Method. — The general plan of the experiments was the same 

 as has been previously described. Much care was taken in pre- 

 paring the food materials selected for the diet, and in taking 

 samples for analysis. The separation of the feces was made 

 by means of lampblack administered in gelatin capsules with 



