INFLUENCE OF FOOD ON METABOLISM. 89 



cent, and a fall in 65 per cent, with a range in average variation from 

 +0.49 F. to -0.71 F. 



While in this comparison only those experiments were used which 

 were included in the minimum metabolism tables, but little if any 

 difference in the results was found when all the measurements were 

 compared. It may be safely concluded, therefore, that there was a 

 tendency in general for the temperature to fall during the experiments 

 and that this was independent of sex. The body temperatures were 

 usually below 100 F. and, if 100 F. at the beginning, generally fell 

 below at the end. This tendency to a fall was undoubtedly due to the 

 contrast between the quiet and muscular relaxation in the experi- 

 mental period and the pre-experimental activity. This interpretation 

 of the change is made the more probable by the fact that, from an 

 inspection of the records showing a rise at the end of the experiment, 

 it appears that in the majority of cases the increase in body tempera- 

 ture was accompanied by a considerable degree of activity in the last 

 period of the experiment. 



In the majority of experiments with children older than 2 years, 

 the temperature measurement was made only at the end of the experi- 

 ment. Accordingly, this comparison of the measurements before and 

 after the experiment applies more particularly to children 2 years old 

 or younger, although some 20 boys and 5 girls are included in the data 

 compared who were over 2 years of age. In conclusion, it may be- 

 said that these observations on the body temperature of young children 

 indicate, on the whole, that during the first two years of life there is a 

 definite tendency for the rectal temperature to increase slightly, with a 

 maximum at about 2 years of age. Thereafter the body temperature 

 slowly falls, with no perceptible general trend apparent from 5 to 13 

 years of age. These variations in temperature show strikingly the 

 desirability of more extensive studies of the diurnal range by means of 

 some more sensitive measurement, such as a bolometric or thermo- 

 electric method, with continuous or semi-continuous registration. 



INFLUENCE OF FOOD ON METABOLISM. 



As outlined in a previous section (see page 30), with the youngest 

 children it was not possible to obtain ideal conditions for measuring 

 the basal metabolism, i. e., complete muscular repose and with no food 

 in the alimentary tract, or the " post-absorptive" condition. With 

 adults the post-absorptive condition is usually not secured until 12 

 hours after an ordinary meal and the maximum increase following a 

 protein-rich meal may be as high as 40 to 50 per cent for a short time, 

 with its effect possibly continued even longer than 12 hours. With 

 the children observed in this study, excessively large meals were not 

 the rule, the last meal before the observations with the respiration 

 apparatus being purposely considerably reduced. 



