440 EEPOET OF OFFICE OF EXPERIMENT STATIONS. 



ness. but nothing definite was accomplished until 1894. In that year 

 the experiment stations were authorized by Congress to cooperate with 

 the Secretary of Agriculture in the study of the food and nutrition of 

 man, and were called upon to report to him the results of such inves- 

 tigations as they might carry out. At the same time Congress provided 

 a special appropriation to enable the Secretary of Agriculture to prose- 

 cute inquiries in this direction. 



GENERAL LINES OF WORK. 



The general lines along which the investigations have been conducted 

 may be briefly stated as follows: 



Observations have been made on the nutritive value and cost of 

 different food materials in various localities in the United States. 



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

 kinds and amounts of food materials consumed by persons in different 

 localities, of different occupations, ages, and sex, and under varying 

 conditions. 



The digestibilit} 7 of certain articles of food, especially cereal prod- 

 ucts and meats, has been studied, and comparisons have been made 

 between the cheaper and rnor,e expensive foods to determine the rela- 

 tive effect of their use on health and comfort. 



Studies have been conducted to determine the losses in nutritive 

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

 nomical methods for utilizing different food materials. 



Metabolism experiments have been made with the respiration calo- 

 rimeter. The principal theme has been the transformation of the energy 

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

 energy 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 and carbo- 

 hydrates 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 

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

 of apparatus. The most important improvements in apparatus thus 

 far made have been the devising and construction of the Atwater-Rosa 

 respiration calorimeter and the improving of the bomb calorimeter by 

 At water and associates. 



The fact was early recognized that compilations and summaries of 

 the investigations which have been carried on in Europe and this 

 country were necessary. In order to conduct any kind of research 

 most efficiently it is necessary to know what has been accomplished by 

 others in order that the investigator may profit by their results and 





