DISCUSSION OF RESULTS. 



167 



square meter of body-surface also show this increase in the same general 

 proportion, since the body-weights of the infants compared are essen- 

 tially the same in all cases. 



Table 36. — Comparison of heat-production of infants of like body-tveight and height, 



but of different ages. 



In the two series of comparisons in which the youngest infant is 

 approximately 6 months old, namely, those comparing E. N. with 

 D. M. and H. T. with E. G., the increase in the heat-production for 

 the older infant is not so great. In the latter comparison, E. G. was of 

 normal weight while H. T. was over weight, so that the excessive amount 

 of fat actually lowered the total heat-production of the younger infant 

 H. T. It is therefore clear that with the older infants, which were in 

 most instances distinctly under weight, there was a deficiency in the 

 fat with an accompanying increase in the proportion of active proto- 

 plasmic tissue. While this method of comparing the metabolism of 

 infants on the basis of weight, height, and age gives a clue to the prob- 

 able preponderance of fat or active protoplasmic tissue, it is obvious 

 that no quantitative relationship can be established on this basis. 



The striking comparison between M. M. and J. M. is particularly 

 worthy of consideration, inasmuch as the value for M. M. is derived 

 from observations on three days, and a total of seven satisfactory 

 periods were available for averaging, while with J. M. the data were 

 secured on two days with six periods for comparison. Here, with a 

 difference of 3| months in the age, there was obviously a much greater 

 proportion of active protoplasmic tissue with the older infant, J. M. 



That the active protoplasmic tissue determined to a very consider- 

 able extent the total katabolism, not only with J. M., but with all of 



