38 PHYSIOLOGY OF THE NEW-BORN INFANT. 



OBSERVATIONS BY BAILEY AND MURLIN. 



In an earlier publication of our work, in which we specifically con- 

 sidered the influence of the age of an infant upon the metabolism 

 per square meter of body-surface, we computed the average values for 

 9 new-born infants ranging in age from 3 hours to 14 days. 1 These 

 results were presented solely for the purpose of discussing the heat 

 production per square meter of body-surface in connection with similar 

 measurements obtained with a large number of atrophic as well as 

 normal infants. Subsequently Bailey and Murlin 2 discussed the 

 energy requirements of new-born infants, chiefly upon the basis of our 

 values, supplemented by their own fragmentary data. It is unneces- 

 sary here to enter into a discussion of their results, for in the light of the 

 researches of Hasselbalch, their investigation can hardty be looked upon 

 as more than a substantiation of the earlier research. 



PURPOSE AND PLAN OF THE RESEARCH. 



The incomplete nature of all of the earlier work with new-born 

 infants and, indeed, of most of the recent studies, the lack of apprecia- 

 tion of the significance of muscular repose during the determination of 

 the total metabolism, and the usually imperfect technique for the 

 measurement of the oxygen consumption, with the consequent liability 

 to error in the estimation of the respiratory quotient, have led us to 

 believe that an extended study of a large number of new-born infants, 

 in which the metabolism during the first week of post-natal life should 

 be definitely established, was not only justifiable, but that the results 

 would be of great significance. 



APPARATUS AND TESTS FOR ACCURACY. 



The respiration apparatus which w r as described in our previous 

 reports of studies on infant metabolism 3 and which has been installed 

 at the Massachusetts General Hospital since January 1913, was 

 employed for the measurement of the respiratory exchange of infants 

 during the first week after birth. The tightness of the apparatus was 

 tested each day to demonstrate the absence of any leakage of air which 

 might affect the oxygen measurements. In addition check tests were 

 frequently made in which the respiratory quotient of alcohol was used 

 as an index of accuracy. In consequence we are confident that the appa- 

 ratus was absolutely tight throughout the whole series of observations. 



We wish, however, distinctly to disclaim absolute accuracy for all 

 of the individual respiratory quotients, for with a series of observa- 

 tions including approximately 1,000 periods and extending over 18 

 months, it is impossible to insure absolute accuracy for the individual 



Benedict and Talbot, Am. Journ. Diseases of Children, 1914, 8, p. 1, tables 13 and 15. 

 2 Bailey and Murlin, Am. Journ. Obstetrics, 1915, 71, p. 526. 



3 Benedict and Talbot, Carnegie Inst. Wash. Pub. 201, 1914, p. 32; also Benedict and Talbot, 

 Am. Journ. Diseases of Children, 1914, 8, p. 21. 



