BASAL METABOLISM. Ill 



An examination of the detailed tables from which this abstract is made 

 shows even more strikingly than with the subjects trained in the use 

 of the apparatus, as were H. L. H., L. E. E., and J. K. M., that there 

 were considerable variations in the individual values. While most of 

 the material from which this abstract is drawn was more fragmentary 

 than that given for the three subjects in detail, there is no evidence 

 of a tendency for the metabolism to change in either direction during 

 the period of experimentation. 



CONCLUSIONS REGARDING SHORT-PERIOD EXPERIMENTS. 



The results just discussed were obtained with men in good health, 

 from 17 to 40 years of age. Unfortunately the observations of the 

 metabolism of individuals over 30 years of age are not so extended as 

 they should be; we are thus unable to state definitely that the lower- 

 ing of the metabolism noted in practically all instances with people of 

 advanced years had not already begun with the subjects about 40 years 

 of age, but our evidence thus far obtained does not lead us to infer this. 



In any attempt to draw general conclusions from these short-period 

 experiments we should depend more especially upon the values found 

 for the oxygen consumption, as, being uninfluenced by the previous 

 diet, they give a clearer picture of the actual metabolism. A general 

 review of the results in tables 37 to 42 and of the results from which 

 the average values in tables 43 to 45 are drawn shows that with all 

 of the subjects the individual values fluctuated considerably at tunes, 

 but that the average values from period to period indicate no general 

 change one way or the other. The average values for the experiments 

 during a period of several months or years show a general constancy 

 in the metabolism, there being but few average values which vary widely 

 from the general average for the whole period. This is emphasized by 

 the fact that the general mean variations for the various subjects were 

 not large. The general constancy in the metabolism during the dif- 

 ferent hours of the day and during different months and years thus 

 seems to be fairly well established by these data, at least for individuals 

 between 17 and 40 years of age. 



The variations in the individual values make clear the fact that 

 single determinations should not be relied upon and that in order to 

 obtain a value for the basal metabolism it is necessary to secure two or 

 three well-agreeing periods for averaging. Inasmuch as the average 

 values from period to period did not tend to change in any one direction, 

 they were evidently free from diurnal influence; this factor may there- 

 fore be eliminated in considering the results of comparison experiments 

 in which the metabolism during fast is first determined and subse- 

 quently the metabolism after food. This leads us, therefore, to the 

 general conclusion that the determination of basal values immediately 

 prior to the ingestion of food is the most logical and satisfactory 

 method for studying the small changes in the metabolism frequently 

 noted after the ingestion of food. 



