NO. 



BODY RADIATION ALDRICH 23 



111 considering the method by which the total radiation values are 

 obtained in these experiments, there will perhaps be question con- 

 cerning the correctness of the empirical division of the body surface 

 into skin, clothing, shoe, and hair areas, as well as the 8% reduction 

 for ineffective radiation between legs and under arms. Yet these 

 factors may be altered through a considerable range and not materi- 

 ally alter the final result. The radiation loss will still be nearly the 

 same magnitude. 



It has been a matter of surprise to the writer that the literature 

 covering calorimetry experiments on the total energy consumption 

 of human subjects makes so little mention of the surrounding tem- 

 peratures to which the subject radiates ; also that in the comparisons 

 between direct and indirect calorimetry the temperatures used are 

 nearly the same throughout. It was my privilege on March 21, 1928, 

 accompanied by Prof. Phelps, of the New York Commission, to visit 

 the Bellevue Hospital laboratory of Dr. Du Bois, to talk with him and 

 see the operation of the Sage calorimeter which, under the skilful 

 manipulation of Dr. Du Bois and his assistants, has added a new chap- 

 ter to our knowledge of metabolism in health and disease. The visit 

 was of especial interest in that Dr. Stefansson, the explorer, was pres- 

 ent for a metabolism test to determine the effect of an exclusively meat 

 diet. Dr. Du Bois explained that the reason all his experiments had 

 been carried out at nearly the same temperature was because of the in- 

 tricacy of the apparatus and the difficulty of redetermining all the con- 

 stants for each set of temperatures. He agreed that it was important 

 to compare direct and indirect calorimetry at other temperatures and 

 indicated that he hoped to find opportunity to do so. 



Incidentally in the course of these experiments, rough tests were 

 made with the thermoelement device to see how rapidly its tempera- 

 ture falls off as the thermoelement recedes from the skin or clothing. 

 The thermoelement has a bright metal surface and consequently its 

 temperature is but little affected by absorption of radiation. The tests 

 show that, in moving the device horizontally away from the body, 

 as soon as actual contact is broken between thermoelement and skin 

 or clothing, the thermoelement temperature falls rapidly almost to 

 room temperature and then gradually declines to room temperature 

 as the thermoelement recedes. At 30 cm. distance no effect of the 

 presence of the body could be detected in still air. There would be a 

 marked effect of course if the thermoelement were held over the 

 body instead of at the side, or if the thermoelement had a better 

 emissivity so that its temperature would be raised by a larger ab- 

 sorption of radiation. 



