922 NUTRITION AND HEAT REGULATION. 



the two groups when the figures are reckoned for a square meter 

 of skin surface.* There is no constitutional difference, so to speak, 

 in the intrinsic metabohzing capacity of the active tissues. On 

 the contrary, there seems to be a rather astonishing uniformity . 



It is to be borne in mind that we know httle or nothing concern- 

 ing the special physiology of the tissue most directly concerned 

 in the deposition of fat, namely, the fat-cells themselves. In a 

 certain way the activity of these cells is antagonistic to that of the 

 other tissues. In proportion as the adipose cells form and store 

 fat out of the material brought to them by the blood they deprive 

 the other tissues of a substance which they might oxidize. Energy 

 that otherwise would be liberated as heat is stored in the form of 

 potential chemical energy. 



While the resting basal metabolism of the fat and the thin 

 person may be alike, it is possible that a diet in excess of this need 

 may be handled differently in the two cases. In one the excess may 

 be all destroyed by the active tissues, while in the other the fat tis- 

 sues may claim a share. Any small difference of this kind in the 

 activity of the adipose cells would have a cumulative effect which 

 would suffice to explain a tendency toward the laying on of fat. 

 Such suggestions as these, however, require some experimental 

 support before they can be considered seriously. 



* Means, "Journal of Medical Research," 32, 121, 1915, and "Journal of 

 Biological Chemistry," 21, 263, 1915. 



