32 A BIOMETRIC STUDY OF BASAL METABOLISM IN MAN. 



These four series are the sources of the constants published in this 

 volume. From the figures given in the protocols in which these data 

 are brought together (pages 38 to 47) the reader who desires to do 

 so may verify the calculation of any of our constants. The exact 

 statement of the several measurements of each individual subject will 

 not have its primary value in the possibility of the verification 

 of the arithmetic of the present work, but in enabling the physiologist 

 to criticize freely our fundamental observations or groupings of 

 observations. 



These series form units of data upon which constants have been 

 based. It may seem to the reader that physiologically more satisfac- 

 tory results might be secured by sorting the entire number of individ- 

 uals in these several series into more homogeneous groups as determined 

 by some special structural or physiological character, for example, 

 according to age, stature, body-weight, body-surface, or pulse-rate. 

 For the sake of argument, at least, this must be admitted. Such 

 divisions will be made in the latter part of this volume. With regard 

 to the question of division of materials the following considerations 

 must be borne in mind. 



In segregating the data for purposes of analysis, two factors must 

 be taken into account. The more finely the materials are sub-divided 

 the more uniform will the groups of observations be, provided, of 

 course, that the divisions are logically made. On the other hand, the 

 smaller the groups are made the larger will be the probable errors of 

 random sampling attaching to the final constants, for these probable 

 errors are inversely proportional to the square roots of the numbers 

 of observations upon which they are based. 



The method of dividing the materials has been determined by 

 both physiological considerations and by the practical exigencies of 

 the work. 



When the application of biometric formulas to the problem of basal 

 metabolism in man was taken up, the only series of data available were 

 the original series of adults and the infant series. These were classified 

 according to sex in both series. 



The women of the original adult series have not been further sub- 

 divided for purposes of general calculation. The men, however, are 

 both more numerous than the women and apparently more hetero- 

 geneous in physiological characteristics. A number are athletes and a 

 number are vegetarians. 



After the work which has been done on the metabolism of athletes 22 

 it would seem unjustifiable to merely lump together athletes, non- 

 athletes, vegetarians and non-vegetarians and all other individuals of 

 the same sex without determining what results are to be secured when 

 they are treated independently. We have, therefore, segregated a 



22 Benedict and Smith, Journ. Biol. Chem., 1915, 20, p. 243. See also page 244 of this volume. 



