PREFACE. 



The immediate development and construction of suitable apparatus for 

 studying the complicated processes of metabolism in man was obviously the 

 first task in equipping the Nutrition Laboratory. As several series of ex- 

 periments have already been made with these respiration calorimeters, it is 

 deemed advisable to publish the description of the apparatus as used at 

 present. New features in the apparatus are, however, frequently introduced 

 as opportunity to increase accuracy or facilitate manipulation is noted. 



We wish here to express our sense of obligation to the following asso- 

 ciates: Mr. W. E, Collins, mechanician of the Nutrition Laboratory, con- 

 structed the structural steel framework and contributed many mechanical 

 features to the apparatus as a whole ; Mr. J. A. Riche, formerly associated 

 with the researches in nutrition in the chemical laboratory of Wesleyan 

 University, added his previous experience in constructing and installing the 

 more delicate of the heating and cooling devices. Others who have aided in 

 the painstaking construction, testing, and experimenting with the apparatus 

 are Messrs. W. H. Leslie, L. E. Emmes, F. L. Dorn, C. F. Clark, F. A. 

 Renshaw, H. A. Stevens, Jr., Miss H. Sherman, and Miss A. Johnson. 



The numerous drawings were made by Mr. E. H. Metcalf, of our staff. 



BOSTON, MASSACHUSETTS, 



August 10, 1909. 



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