224 A BIOMETRIC STUDY OF BASAL METABOLISM IN MAN. 



fiercely about the normal controls than about the pathological cases." 2 

 The difficulty has been twofold. First, the measurement of an ade- 

 quately large series of individuals has been a very heavy undertaking. 

 Second, the selection of the proper measure of metabolism in the 

 control series has presented theoretical difficulties. In relation to the 

 first of these we may quote a statement made as late as 1914: 3 



"The impetus given to the study of gaseous and gross metabolism during 

 the past decade has resulted in a large number of observations, both in the 

 domain of physiology and pathology. Investigators in pathology are, how- 

 ever, continually confronted by the paucity of normal data with which to 

 compare their observations." 



Somewhat later Gephart and Du Bois 4 wrote : 



"The importance of the normal control has been emphasized so strongly 

 by the serologists and the management of the control has been developed by 

 them to such an art that it has seemed advisable to apply some of their methods 

 of critique to the study of the respiratory metabolism These precau- 

 tions .... have been made necessary by the fact that the normal control is 

 usually the point of attack in serological controversies. Likewise in the study 

 of metabolism the normal control is coming to be recognized as the weakest 



part of the experiment The literature is notoriously filled with false 



theories, of which by far the greater part would never have been promulgated 

 if sufficient attention had been given to normal controls." 



Notwithstanding the confidence which has generally prevailed in 

 the validity of the expression of metabolism in calories per square meter 

 of body-surface area, the theoretical difficulties in the selection of 

 control series have not passed unrecognized. "The selection of the 

 proper normal base-line is a matter of extreme difficulty." The 

 detailed discussion in the preceding chapters of the factors associated 

 with variations in basal metabolism suggests that the difficulties of 

 the selection of proper controls has been underestimated rather than 

 overestimated in the past. 



A brief consideration of the fundamental principles of the estab- 

 lishment of standard or control constants to be used as a basis of com- 

 parison in experimental work is in order. 



In the simplest cases the metabolism of an individual under any 

 exceptional condition may be compared with his own basal metabolism 

 which serves, therefore, as a standard or control. This is true, for 

 example, in the case of variations in muscular activity, in rationing 

 or in prolonged fasting. Even in the case of protracted illness, sugges- 

 tion has been made of the possibility of using basal metabolism deter- 

 minations upon the same individual, obtained subsequent to recovery, 

 as a basis of comparison with the constants secured when the subject 



2 Du Bois, Am. Journ. Med. Sci., 1916, 151, p. 785. 



3 Benedict, Emmes, Roth, and Smith, Journ. Biol. Chom., 1914, 18, p. 139. 



4 Gephart and Du Bois, Arch. Intern. Mod., 1915, 15, p. 835. 

 6 Gephart and Du Bois, Arch. Intern. Med., 1915, 15, p. 858. 



