470 



REPORT OF OFFICE OF EXPERIMENT STATIONS. 



a number of European experiments with dogs. It would perhaps be 

 going too far to say that the experiments with the respiration calorim- 

 eter by Professor Atwater and his associates at Wesleyan University 

 have sufficed for the absolute and final proof, but certainly the results 

 leave scarcely any room for doubt. As the outcome of 44 experi- 

 ments with five different men, covering a period of 134 days, the ratio 

 of the potential energy of the material oxidized in the body to the 

 energy given off from the body in the forms of heat and muscular 

 work, as measured by the respiration calorimeter, is as 1,000 to 999. 

 The same ratio of 1,000 to 999 was found in the average of a number 

 of experiments made to test the accuracy of the apparatus. Closer 

 agreement than this could not be looked for. 



The practical usefulness of this apparatus and method of inquiry 

 will be realized more clearly when we consider that it gives us a means 

 for measuring so accurately the transformations of both material and 

 energy. It may be said also that the measurements of the income 

 and outgo of material are nearly as accurate as those of energ} r . We 

 have thus the means for studying the effects of different diets, differ- 

 ent kinds and amounts of food in the body, the effects of different 

 forms of work and of rest upon the consumption of material, the 

 nutritive values of different food materials, and are thus enabled to get 

 at the very foundations of the doctrine of nutrition. 



FACTORS FOR DIGESTIBILITY AND FUEL VALUE OF NUTRIENTS. 



The data obtained in the nutrition investigations may be used in 

 deducing certain factors which are useful in various ways to students 

 and investigators of similar problems, and to some extent also to those 

 who wish to make practical application of the results. These factors 

 are epitomized in the following table: 



Factors for digestibility and fuel value of nutrients of food materials. 



