ELEMENT OF NOVELTY IN MEASUREMENTS OF METABOLISM. 99 



With the majority of the subjects the observations were made on 

 succeeding days, and with few exceptions not more than three days 

 apart. These exceptions were Nos. 209, 238, and 260, with whom 

 the observations were made 17, 7, and 5 days apart, respectively. 

 The agreement in the values for the heat production for the two days 

 is, in most cases, reasonably close. The results for the second day are, 

 in many instances, lower than those for the first day, but the reverse 

 is likewise true, so that, taking the plus and minus signs into considera- 

 tion, one may state that the general average difference between the 

 first and second day for all of the children is but 17 calories. Bearing 

 in mind the difficulty of estimating relative activity from day to day, 

 especially at the lower grades of activity, we find that the records of 

 the relative activity in the last column of table 24 indicate that the 

 average activity on the two days was equal. 



Of special significance, however, is the pulse-rate, both when com- 

 pared for the first and second days of experimenting and particularly 

 when compared with the value for the total heat production. In the 

 majority of instances the pulse-rate is lower on the second day than 

 on the first day, the average of the values for all of the children on the 

 second day being 78 beats per minute as compared with 83 beats on 

 the first day. In many cases the pulse-rate is notably lower on the 

 second day. The influence of "training," so to speak, is thus definitely 

 towards a decidedly lower pulse-rate. A few instances of a higher 

 pulse-rate on the second day occur, these being found with three 

 boys, Nos. 194, 204, and 242, and with one girl, No. 178. The largest 

 change is with the boy No. 256, whose pulse-rate fell from 87 to 72, 

 or a total change of 15 beats. Changes of 9 or 10 beats are noted in 

 several cases, especially with the boys. With these larger pulse-rate 

 changes, there is in most cases a corresponding change in the metabol- 

 ism, a fall in the pulse-rate being accompanied by a downward tendency 

 in the metabolism. The changes are, however, by no means uniform, 

 and the reverse is not infrequently found, namely, a lowering in pulse- 

 rate with a slight increase in metabolism. This lack of harmony 

 between pulse-rate and metabolism, which is more particularly evident 

 with the girls, is sufficient to show that with children in the growing 

 period there apparently is much less correlation between pulse-rate 

 and metabolism with the same child than is found either with younger 

 children or with adults. 



When the data are examined with reference to their grouping as to 

 sex, some difference is shown in the values. It might be expected that 

 the boys would give results for the second day but little, if any, lower 

 than for the first day, as they would naturally be less apprehensive 

 and sensitive to outside influences than the girls and even enjoy the 

 novelty of the experience. The data, however, show that with the 

 boys there was almost invariably a fall on the second day, but three 



