l86 REPORTS ON INVESTIGATIONS AND PROJECTS. 



which gives very accurate determinations of the respiratory exchange in 

 short periods. Utilizing the experience he obtained in both the French and 

 German laboratories, Mr. T. M. Carpenter has during the past year begun 

 this comparative study of the methods of determining the respiratory ex- 

 change, using these three types of apparatus. A preliminary study of the 

 respiratory exchange after a short fast has already been made and the in- 

 vestigation will be carried further. These results will also be compared with 

 the results obtained with the bed calorimeter, which gives accurate deter- 

 minations of the respiratory exchange in periods i hour in length. A com- 

 parison of these methods is deemed of vital importance by many foreign 

 investigators. 



INFLUENCE OF OXYGEN-RICH MIXTURES UPON THE RESPIRATORY EXCHANGE. 



The respiration apparatus, of which mention has already been made, offers 

 a peculiarly advantageous opportunity for the study of the influence of 

 oxygen-rich mixtures upon the respiratory exchange, and accordingly ex- 

 periments were carried out along this line during the earlier part of the year. 

 Using normal atmospheric air, a large number of experiments were made in 

 which the respiratory exchange was determined 12 hours or more after the 

 last meal. The percentage of oxygen in the apparatus was then arbitrarily 

 increased and the respiratory exchange again determined under identically 

 the same conditions and on the same day, except that the air used was rich in 

 oxygen, 90 per cent or more. Five or six different individuals have been 

 used as subjects, with different percentages of oxygen, and it is expected 

 that the results of these experiments will throw very definite light upon the 

 question of the oxygen absorption with oxygen-rich mixtures. The work 

 has been carried out by Mr. H. L. Higgins of the laboratory staff. 



THE INFLUENCE OF THE PRECEDING DIET UPON THE RESPIRATORY EXCHANGE. 



In the last report reference was made to a study which had been begun on 

 the influence of the previous diet upon the respiratory quotient. It was ex- 

 pected at that time that the results of this study would soon be published, but 

 it was deemed advisable to continue the work further. This investigation 

 has also been supplemented by noting the effect of diet upon fasting value in 

 connection with the investigation upon the effect of oxygen-rich mixtures. 

 Considerable data have been added in this manner and the whole material is 

 now being prepared for publication. 



TOPOGRAPHICAL STUDY OF BODY-TEMPERATURE. 



The desirability of a topographical study of body-temperatures has been 

 increasingly apparent in the work of the laboratory and plans for a thorough 

 investigation of the subject have long been made. Mr. Edgar P. Slack has 

 been at work during the past year compiling material upon this topic and 

 constructing thermometers and accessory apparatus to be used in connection 

 with the research. In the investigations a simultaneous study will be made 

 of the temperature of the different portions of the body, such as the mouth, 

 stomach, colon, vagina, and axilla, and upon various parts of the body- 



