28 PHYSIOLOGY OF THE NEW-BORN INFANT. 



It is quite clear to me that in investigating these circumstances it 

 would have been experimentally more correct to have used the same 

 instead of different infants. The material for the investigations, how- 

 ever, was collected for another purpose. Nevertheless the dependence 

 of the respiratory quotient upon the interval of time elapsing after 

 the last meal is shown in table 4, and in such a striking manner that 

 there can hardly be any other interpretation. 



There is, however, no doubt about one point. Even though the 

 composition of the food of the infant is much more constant than that 

 of the adult, the respiratory quotient of the infant varies continually 

 with the meals, so that it is highest about 1| hours afterwards (during 

 this period the metabolism of lactose is chiefly going on) , and very low 

 about 5 hours after, when the lactose from the last meal had been 

 used up. I would not insist that this is definitely in favor of more 

 frequent feeding than the ordinary 5 feedings during the course of the 

 day, but it certainly deserves some consideration. 



On the other hand, it is possible that it might be harmful to the infant 

 if the meals were so near together that the respiratory quotient remained 

 constant throughout the day. In any case the problem is interesting 

 and deserves a more thorough investigation, especially in the case of the 

 same child throughout a rather long interval of time, with varying 

 frequency of feeding with the same quantity of food and under constant 

 control of the weight curve. 



Table 4 does not give any new information concerning the amount 

 of the metabolism. The influence of activity is also quite apparent 

 here. The premature incubator infant in experiments 15 and 16, 

 which was practically motionless during the experiments, has a metabo- 

 lism even lower than that found in the experiments with infants 

 immediately after birth; it is interesting to note that the metabolism 

 rises in the second experiment (both the carbon dioxide produced and 

 the oxygen consumed), because this is supposedly to be interpreted in 

 the same manner as the rise of the quotient in experiment 16. The 

 work of digestion is greater in experiment 16 than in experiment 15. 

 At any rate, it was impossible to recognize a difference in the muscular 

 activity of the infant in the two experiments, as the child was lying 

 relaxed and asleep. The quotients for the infants spoken of as "lively 

 and content" are somewhat higher than those of similar cases in tables 

 1, 2, and 3; but it is also striking how much more energy is displayed 

 by the child a few days old than by the new-born infant, exhausted 

 after birth. 



In experiment 30 we find an enormous metabolism, 642 c.c. of carbon 

 dioxide per kilogram and per hour; but in this case we observe that the 

 child was " violently crying more than two-thirds of the time." Evi- 

 dently we can not overestimate the increased metabolism due to the 

 incessant crying of feeble infants. 



Experiment 27 (not given in the tables) illustrates the effect of crying 

 on the amount of the metabolism. By moderately lowering the tem- 

 perature (which caused a drop in the body-temperature of 0.4 C.) we 

 succeeded in making the child cry very violently for about 17 min- 



