304 



CARNEGIE INSTITUTION OF WASHINGTON. 



vegetarians the slight difference in metabolism shown by the male vegetarians 

 did not appear. We may therefore fairly conclude that living upon a vege- 

 tarian diet for a longer or shorter period does not fundamentally alter the 

 basal gaseous metabolism. A study of the respiratory quotients obtained for 

 both classes shows results wholly incompatible with the belief that vege- 

 tarians, when in the post-absorptive condition, have a considerably larger 

 proportion of easily combustible carbohydrate material (glycogen) than have 

 non-vegetarians. 



(3) The basal caloric output of vegetarians as compared with that of non-vegetarians of 



like weight and height. PYancis G. Benedict and Paul Roth. Proc. Nat. 

 Acad. Sci., I, 100 (1915). 



An abbreviated presentation of the material in the foregoing article. 



(4) The metabolism of athletes as compared with normal individuals of similar height and 



weight. Francis G. Benedict and H. Monmouth Smith. Journ. Biol. Chem., 

 20, 243 (1915). 



Two fundamental conceptions exist with regard to the heat-production of 

 the body. One is that the heat-production is in proportion to the active mass 

 of protoplasmic tissue and the other, a more generally accepted view, is that 

 the heat-production is in proportion to the surface area of the body. An 

 investigation was made upon the metabolism of a number of trained college 



Summary of comparison of athletes arid non-athletes. 



athletes, in whom the proportion of active protoplasmic tissue was undoubtedly 

 much greater than in the body of a normal untrained individual. Differences 

 in surface area were eliminated by making comparisons only between different 

 groups of individuals of like height and weight. Several groups corresponding 

 to various weights and heights were studied, and a final comparison of athletes 

 and non-athletes may best be made by an examination of the summary of all 

 groups given in the table herewith. 



It is seen from the general picture of the comparison that the conclusion 

 may justly be drawn that athletes have a somewhat higher metabolism, both 

 per Idlogram of body-weight and per square meter of body-surface, than do the 

 non-athletes with whom they may have been compared, and the belief is 

 expressed that the greatly increased proportion of active protoplasmic tissue 

 present in the trained, hardened athlete is alone sufficient to account for the 

 increase in metabolism. 



