6 A RESPIRATION CALORIMETER. 



An account 1 of the first form of the apparatus, published in 1897, 

 consists of the description of a respiration chamber on the Pettenkofer 

 principle, the arrangements for ventilating the same, and the accessory 

 apparatus for analyzing the air of the chamber. With this description 

 was included a report of four experiments in which the intake and 

 output of nitrogen, carbon dioxide, and water were determined. Satis- 

 factory determinations of the output of energy by means of the apparatus 

 were not yet possible. 



In 1899 a description 2 of the apparatus in its next stage was published. 

 This included a discussion of the measurement of heat eliminated from 

 the body, together with a much more detailed description of the respi- 

 ration chamber, accessory apparatus, and methods of manipulation and 

 analysis. In this report was given a brief account of two experiments 

 with man in which the balance of intake and output of both matter and 

 energy was determined. 



A few months later another report, 5 giving a detailed description of 

 six metabolism experiments with men, including the methods of calcu- 

 lating and interpreting the results, was published ; and this was fol- 

 lowed in 1 902 by a report 4 in which were given the results of twenty- 

 four experiments with men and a general discussion of the same. A 

 more extensive report & of the results of twenty-six more experiments 

 with men was published in 1903. This report gives also an account 

 of many improvements and modifications of apparatus that had been 

 developed in the course of the experiments ; and as the series of inves- 

 tigations with the respiration calorimeter essentially as originally 

 devised was completed, considerable discussion of general principles 

 and deductions based upon results of the whole six years of experi- 

 mentation was included. 



In addition to the research reported in the publications above referred 

 to, the apparatus has been used for an investigation into the nutritive 

 value of alcohol, the results of which are published in a separate report.' 

 This report gives the detailed description and discussion of the results 

 obtained in thirteen experiments with men in which alcohol formed a 

 part of the diet. 



None of the experiments above referred to, however, were actually 

 complete metabolism experiments, for the reason that determinations of 



1 U. S. Dept. of Agr., Office of Experiment Stations Bull. 44. 



2 U. S. Dept. of Agr., Office of Experiment Stations Bull. 63. 



3 U. S. Dept. of Agr. , Office of Experiment Stations Bull. 69. 



* U. S. Dept. of Agr., Office of Experiment Stations Bull. 109. 



6 U. S. Dept. of Agr., Office of Experiment Stations Bull. 136. 



8 W. O. Atwater and F. G. Benedict: Mem. Nat. Acad. Sci. (1902), 8; U. S. 

 Senate, 57th Cong., first sess., Doc. 233, p. 231. An experimental inquiry on the 

 nutritive value of alcohol. 



