82 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



From the foregoing discussion of the considerable variation to be 

 found with an individual in the earlier years, one would naturally 

 expect similar large differences between groups of older children of the 

 same age. The considerable amount of data obtained for the first 

 four years of a child's life have been supplemented by records for older 

 children, which are given in table 19 for boys and girls 5 to 13 years 



TABLE 19. Basal pulse-rate of individual children 5 to 13 years of age. 



of age. Almost without exception, however, the averages in this 

 table represent individual children, the data for each child, except in 

 one case, being obtained at only one age. Here again we find con- 

 siderable differences. Thus, for the 7 boys 7 years of age, the lowest 

 is 74 and the highest 99. With the 5 boys 9 years of age, the lowest 

 record is 71 and the highest 86, while the 9 boys 11 years of age show a 

 maximum difference in their basal pulse-rates of 22 beats. 



With girls, one of the largest groups at the earlier ages is that for 

 6 months, but the pulse-rates for these 8 girls range only from 118 to 

 132, with an average of 124. This approach to uniformity, which is 

 much closer than that noted for boys, does not by any means hold for 

 all ages, since at 16 and 18 months differences amounting to 40 and 

 32 beats, respectively, are observed. The largest group for the older 

 ages represented in table 19, that for 9 years, has values for pulse-rate 

 for the 6 girls ranging from 71 to 97. The extraordinarily high value 

 of 114 for one of the 5-year-old girls may have some special explanation 

 which is at present unknown to us. 



Bearing in mind the irregularities seen in the careful examination 

 of the data for these several age-groups, we may average these pulse 

 data and attempt to portray the general trend of the minimum or 

 basal pulse-rate of boys and girls from birth to 13 years of age. In so 

 doing we have left out of the averaging all age-ranges represented by 

 less than three individuals. These values are brought together in 

 table 20. 



The average values shown for boys indicate a reasonably constant 

 pulse-rate for the first 14 months of life, ranging from 113 to 125, if 



