242 A BIOMETRIC STUDY OF BASAL METABOLISM IN MAN. 



the curves published in previous papers." Thus their earlier diagram 

 agrees with our equation in indicating that the observed metabolism 

 of these old men is abnormally high. The remarkable agreement of 

 5 of the men in their figure 2 with the old-age portion of their line 

 and the obvious bad results with our equation are, therefore, due to 

 the fact that their prediction line has been redrawn to fit the special 

 observations, while our own has not. 



The explanation of these results is a problem of considerable diffi- 

 culty. Of course, one thinks first of all of the question of muscular 

 repose. Were these octogenarians as quiet as the younger individuals 

 with whom they are compared? We must note that even for the years 

 of maturity the constants of Magnus-Levy and Falk are higher than 

 the American standards. If this result be due to faulty technique it 

 may account for the high values of the old men and women measured 

 by them. 



It seems to us quite as possible that the discrepancy indicates not 

 the invalidity of our formula but the selected character of the 6 old 

 men studied by Aub and Du Bois. In the course of their discussion 

 they remark : 



"It will be noted that the metabolism of Charles W. was unusually low. 

 This may be accounted for by the fact that he was much more senile than the 

 others. While this finding is of importance in showing the great depression 

 in metabolism which may occur in old age, we are not justified in using it to 

 obtain the average figure which represents the heat-production of men of his 



age The results on Charles W. show a deviation of 21 per cent from 



the average of the other old men. He is therefore excluded from the averages 

 as the result of the rule which debars an observation in which the deviation 

 from the mean is greater than 4 times the average deviation." 



Our formula gives the metabolism of Charles W. within slightly 

 more than 77 calories per day, or with an error of only 5.9 per cent of 

 the calculated metabolism. On purely general grounds there seems 

 to be no more reason to exclude Charles W. because he was too senile 

 for his age than to exclude the other 5 men because they were too 

 juvenile for their age. 20 



It must not be forgotten that men who reach 75 or 80 years are 

 by virtue of this very fact a selected class. By this time a large pro- 

 portion of humanity has succumbed to the wear and tear of life. Few 

 are able to totter forward many paces further. Those who march 

 with vigor are not typical of their age. But in selecting subjects for 

 metabolism work, individuals in presumably good health are chosen. 

 In examining the case-histories of the old men studied by Aub and 

 Du Bois one is rather impressed by the idea that they must have been 

 physically very remarkable individuals. Certainly in reading that 



20 If Charles W. is to be excluded, this should certainly have been done before his metabolism 

 was measured. 



