194 DEPARTMENTAL REPORTS. 



Mtive system has proved to be economical and efficient, procuring the 

 services of more trained workers and the collection of a larger amount 

 of data than would be possible if only the fund appropriated by Con- 

 gress for this purpose were used. In addition, it creates a more wide- 

 spread interest in the work, permits the studj^ of nutrition problems 

 under varying conditions, and educates a considerable number of 

 investigators along these lines. It makes it possible to extend the 

 inquiry to different regions, and the results are more immediately 

 available to the different parts of the countr3\ 



GENERAL LINES OF WORK. 



The general lines along whicli the investigations have been con- 

 ducted the past year may be briefly stated as follows: 



Observations have been made on the nutritive value and cost of dif- 

 ferent food materials in various localities in the United States. These 

 W'Cre less extended than in some previous years and were mostly in 

 connection with dietar}^ studies. 



Studies have been made of actual dietaries in order to learn the kinds 

 and amounts of food materials consumed by people in different local- 

 ities, of different occupations, ages, and sex, and under A^aryiug 

 conditions. 



The digestibilitj^ of certain articles of food, especiallj' cereal prod- 

 ucts, has been studied, and comparisons have been made between the 

 cheaper and more expensive foods to determine the relative effect on 

 health and comfort by their use. 



Studies have been conducted to determine the losses in nutritive 

 value from various modes of cooking and to find out the most econom- 

 ical methods for utilizing different food materials. 



Metabolism experiments have also been continued with the respira- 

 tion calorimeter. The i^rincipal theme lias been the transformation 

 of the energy of food materials in the body and the use which the body 

 makes of the energ}^ so transformed. One important topic has been 

 the relation of muscular work to digestibility and metabolism. The 

 amounts of food consumed and metabolized by men under different 

 conditions of work and rest have been observed. The fuel values of 

 the fats, carbohj^drates, and alcohol have been compared. 



Determinations of the heats of combustion of food materials have 

 been made with the bomb calorimeter. 



Methods of investigation are being studied with reference to their 

 imijrovement, and constant effort is being made to devise better forms 

 of apparatus. 



The current literature of the nutrition of man, which is now qi.ite 

 voluminous, is being regularly followed up, and such abstracts and 

 compilations are being made as will promote the interests of our 

 investigations. 



The rapid accumulation of material which must be made ready for 

 publication in both technical and popular form necessitates a large 

 amount of editorial work. The correspondence connected with these 

 investigations has grown to be extensive. 



THE WORK AT DIFFERENT PLACES. 



The work of the Washington Office in relation to the nutrition inves- 

 tigations during the past year has included a general supervision of 

 the plans and expenditures; editorial work in perfecting the details 

 of reports of investigations; collection of bibliographical data; the 



