72 A BIOMETBIC STUDY OF BASAL METABOLISM US MART. 



sider measures of the degree of interdependence of pulse-rate and 

 gaseous exchange and total heat-production. With these data at our 

 disposal, we shall proceed to a consideration of the relationship between 

 physical characters and metabolism. 



Since the physical characteristics, stature and weight, have been 

 shown to be correlated, it is sometimes necessary in discussing the 

 relationship between either of these and physiological characters to 

 anticipate results to be given in detail later. 



I. WEIGHT AND PULSE-RATE. 



In the series of normal infants we find the correlation between 

 weight and pulse-rate, r w!fn and the test of significance furnished by the 

 ratio of the constant to its probable error, r E,,: 



For males ^=51, r^ =0-3114 *a0853, r/Kr=&65 



For females 3^=43, r a ^=0.1S2'0*0.1003 I , r/& 



0.1544*0.1317 



For both ^=94, ^=0.2289*0.0659,, r/^ 



The coefficient for females is only about 1.5 times as large as its 

 probable error, and so can not be considered to prove that there is any 

 correlation whatever between pulse-rate and body-weight. 



The value for boys is numerically larger than t hat for girls, but in 

 comparison with its probable error the difference between the constants 

 for the two sexes is not statistically significant. 



The constant for the male babies and that for male and female 

 babies suggest a real interdependence between weight and pulse-rate, 

 but the number of individuals is, statistically speaking, so small that 

 caution must be used in asserting that in male infants as a class there 

 is any relationship between pulse-rate and body-weight. 



Even if one be inclined to accept these correlations as indicating a 

 real physiological relationship between body-weight and pulse-rate, 

 he must remember that it can not be asserted, without further analysis, 

 that there is a direct biological nexus between body-weight as such 

 and pulse-rate. Body-weight is correlated with stature, and it is quite 

 possible that the observed correlation between body-weight and 

 pulse-rate is in part at least the resultant of correlations between 

 stature (length) and body-weight and between stature (length) and 

 pulse-rate. 



Furthermore, one must remember that all these variables may 

 change with age, and that in any detailed investigation covering the 

 whole period of life such age changes must be fully taken into 

 account. 



Consider first of all the correction to the correlation between 

 weight and pulse-rate to be made for stature. The partial correlation 



