STATE OF NUTRITION. 199 



presented by these values was far from indicating constancy. As 

 would be expected, large men as a rule produced more heat than small 

 men and large women more than small women. But when the calcu- 

 lations were made on the basis of per kilogram of body-weight, it was 

 found that the heat production even on this basis varied for the men 

 from 19.7 to 32.3 calories, with an average value of 25.5 calories. 

 Nearly one-third of the observations fell outside of the extreme limits 

 of plus or minus 10 per cent. Thus, on the basis of per kilogram of 

 body-weight, there appeared to be no evidence with a sufficient degree 

 of constancy to establish a '4aw." 



Closer analysis of certain of the figures showed that in a group of 

 athletes practically no values were found in the lower range, and that 

 the heat production for the group lay for the most part somewhat 

 above rather than below the average value of 25.5 calories per kilogram 

 of body-weight. The measurements obtained for the women indicated 

 a lower metabolism per kilogram of body-weight than the metabolism 

 of men of corresponding height and weight. Like comparisons on the 

 basis of per square meter of body-surface showed similar lack of con- 

 stancy. From these values, therefore, it would be perfectly legitimate 

 to conclude that athletes as a class have a somewhat higher metabolism 

 than non-athletic individuals of the same height and weight and that 

 women have a somewhat lower metabolism than men. Thus, we have 

 the first definite proof of differences in the metabolism of different 

 classes of individuals. 



This lack of constancy in metabolism is further confirmed by an 

 examination of all our data obtained throughout many years of ex- 

 perimenting, new-born infants, young children, youths, and elderly 

 individuals alike indicating very considerable variations from the so- 

 called standard or normal figures. In recent years the attempt has 

 been made to recognize these variations and to replace the single 

 standard by a convenient scale of standard figures which should take 

 into consideration age and sex. This i^ certainly a step in the right 

 direction, but must be looked upon as a preliminary to the abolishment 

 of the surface-area law. An extensive biometrical treatment of the 

 basal metabolism data obtained in the Nutrition Laboratory is in 

 press. From these data a series of tables has been derived which 

 may be used for the prediction of the probable metabolism of men 

 and women of varying weights, heights, and ages. 



METHOD OF PRESENTING DATA FOR BASAL METABOLISM. 



While there has been much quibbling over the method for presenting 

 the data for basal metabolism, some writers stoutly maintaining that 

 a basal metabolism determined in short periods should be expressed in 

 values per half hour or per hour, the fundamental computation of basal 

 metabolism must, in the last analysis, deal with the 24-hour period. 



