218 DEPARTMENTAL REPORTS. 



the meat with reference to comi)osition, digestibility, nutritive value, 

 and pecuniary economy. 



The metabolism experiments have been conducted mostly at Middle- 

 town, with the aid of the respiration calorimeter. In these experiments 

 the income and outgo of the body were carefully observed under dif- 

 ferent conditions of rest and work. The questions especially con- 

 sidered this year were (1) the relation between muscular work and 

 the metabolism of nitrogen, and (2) the relative efiieiency of fats 

 and carbohydrates in the diet for severe muscular work. .The results 

 obtained have been unusually interesting and valuable. 



All these expei'iments include a large amount of analytical work as 

 well as the determination of a considerable number of heats of com- 

 bustion by means of the bomb calorimeter. 



Considerable editorial work is also required to put the results of 

 the investigations in form for publication as either technical or pop- 

 ular bulletins. The amount of editorial work has been somewhat 

 larger this year than usual. 



THE W^ORK AT DIFFERENT PLACES. 



The work of the Washington office in relation to the nutrition 

 investigations during the past year has included a general super- 

 vision of the ijlans and expenditures; editorial work in perfecting the 

 details of reports of investigations; collection of bibliographical data; 

 the abstracting of the literature of nutrition, partly for publication 

 in the Experiment Station Record; the conducting of a large corre- 

 spondence growing out of the nutrition investigations, and the dis- 

 tribution of publications on this subject. 



The work of the office of the special agent in charge of the nutri- 

 tion investigations at Middletown, Conn., has included the planning 

 and direct supervision of these investigations in different parts of the 

 country, the conducting of special investigations with the i-espiratiou 

 calorimeter and bomb calorimeter, the compilation of the results of 

 nutrition investigations in this country and abroad, and a large corre- 

 spondence relating to these investigations. The special investigations 

 carried on here the past year in cooperation with Wesleyan University 

 and the Storrs Experiment Station have included an unusually large 

 amount of experimental work with the respiration calorimeter. The 

 principal objects of these investigations Avere to stud}' the relation be- 

 tween muscular work and the relative efficiency of fats and carbo- 

 hydrates in the diet for severe muscular work. Other observations 

 made Avere of the amount of heat liberated by the bodj^ during the 

 period of digestive inactivity as compared with the period when 

 digestion is going on, the metabolism of nitrogen during fasting, and 

 variation of body temperature under different conditions. Four series 

 of experiments, covering a j)eriod of nine days each, and a sliorter 

 series of five days, were conducted during the year. With but one 

 exceijtion, each series included three experiments — two of four days 

 each, followed by one of one day. During the first two experiments of 

 the longer series the subject performed severe muscular labor, riding a 

 stationary bicycle eight hours in the day. In one of the experiments 

 a diet rich in carbohydrates was given to the subject, while in the 

 other a diet rich in fats was provided, the amounts of protein and 

 energy being essentially the same, as well as the amount and char- 

 acter of the work. Two pairs of experiments were followed by an 

 experimental day of rest and fasting. Two other pairs were followed 



