226 REPORTS ON INVESTIGATIONS AND PROJECTS. 



volumetric methods for the determination of copper in alkaline tartrate 

 liquids. The needs of this laboratory for the accurate and rapid determina- 

 tion of sugar in urine are such as to demand especial technique. After a 

 series of experiments in which were studied the process of reduction, the 

 standardization of the heating power, and the influence of changes in time 

 and temperature upon the reduction, conditions were so controlled that a 

 series of constant tabular values for the reducing power of pure dextrose 

 were obtained. The research was characterized primarily by the quantita- 

 tive standardization in detail of the conditions of reduction, and of the 

 volumetric estimation by the iodide method of the copper in alkaline tartrate 

 solutions. The method has been applied with good results to the determina- 

 tion of the reducing power of urine as well as other physiological materials. 



(6) Ein Universalrespirationsapparat. Francis G. Benedict. Deutsch. Archiv f. klin. 



Med., 107, p. 156. 1912. 



Since the original description of the respiration apparatus devised in this 

 laboratory was published in 1909, many alterations have been made in the 

 apparatus which adapt it not only for experiments with men but also, by the 

 addition of different types of respiration chambers, for experiments with 

 infants and animals ; it is accordingly now designated "a. universal respira- 

 tion apparatus." This paper includes an elaborate presentation of all the 

 technique in the actual use of the apparatus, and describes some new features 

 Avhich have been added with particular reference to studying the mechanics 

 of respiration. It also describes in detail a method for measuring the oxy- 

 gen consumption by means of a meter, and methods for testing the apparatus 

 for tightness, and shows its adaptation to experiments with severe muscular 

 work and to experiments with animals or infants. A description of the 

 method of calculating the results, together with the presentation of data 

 obtained from several experiments, completes the paper. The normality 

 of the results is shown by a comparison of the experimental values obtained 

 on this apparatus with those obtained with the bed calorimeter when the 

 subjects are lying quietly, breathing without any special respiratory require- 

 ment. This paper, which represents the first complete description given in 

 a foreign language, was written primarily to assist many European investi- 

 gators in this field who are now planning to use the apparatus in their 

 researches. 



(7) The composition of the atmosphere with special reference to its oxygen content. 



Francis G. Benedict. Pubhcation No. 166, Carnegie Institution of Washing- 

 ton. 1912. 



The marked change in composition of the air as it passes through the 

 lungs is of great value in estimating the character of the combustion pro- 

 cesses in the body. For a quantitative understanding of these processes, 

 an exact knowledge of the composition of the outdoor air is essential. The 

 first part of this publication consists of an extensive review of earlier liter- 

 ature and a history of air-analysis. The present-day view of the composi- 

 tion of the air is well summed up by F. W. Clarke,* who says : 



"In a roughly approximate way it is often said that air consists of four- 

 fifths nitrogen and one-fifth oxygen, and this is nearly true. The propor- 

 tions of the two gases are almost constant, but not absolutely so; for the 

 innumerable analyses of air reveal variations larger than can be ascribed to 

 experimental errors." 



* Data of Geochemistry, U. S. Geological Survey Bui. 330, 1908, p. 38. 



