INFLUENCE OF FOOD ON METABOLISM. 95 



obtained 1 hour 41 minutes after the third feeding, was 336 calories, 

 there was a maximum rise of 81 calories, or approximately 30 per cent. 

 Singularly enough, there was no marked change in the pulse-rate, the 

 maximum increase being but a few beats. 



The series of observations with No. 115 after the two feedings agree 

 very satisfactorily, although the question of the actual basal value is 

 in doubt, since this must be taken as but 3 hours and 11 minutes after 

 the second feeding. The total increase on this basis is, therefore, 66 

 calories, or about 22 per cent above basal. 



The observations with the other children were approximately 3 to 6 

 hours in length and usually indicate the minimum at the end of the 

 period of observation, with maximum increases shortly after food was 

 taken, these corresponding to not far from 20 to 30 per cent with most 

 of the children. Of special interest with No. 119 is the fact that in 

 the second feeding the energy in the food was almost three tunes that 

 in the first feeding, and under these conditions a distinctly higher 

 metabolism was noted. If we accept the basal value as 369 calories, 

 which was obtained 5 hours and 41 minutes after the feeding of 80 

 calories in breast milk, we find an increase of 108 calories 1 hour and 

 50 minutes after the second feeding of breast milk with an energy con- 

 tent of 210 calories. This increase after the second feeding corre- 

 sponds to about 29 per cent, as compared with the maximum increase 

 of 34 calories, or 9 per cent, 1 hour and 8 minutes after the first feeding 

 of a very much smaller amount of breast milk. With No. 140, who 

 was the same age as No. 119, the energy content of the milk in the 

 first feeding was 70 calories, while that of the second feeding was 170 

 calories. Here the increase due to the larger amount of milk was 

 very slight, if any. It is also worthy of note that No. 136, after 

 a second feeding, showed a maximum heat production no greater 

 than that found after the first feeding, although the second feed- 

 ing had an energy content four or five times larger than that of the 

 first. 



From an inspection of the data in table 23 it is clear that in most 

 instances the absolute minimum values were not found before 8 to 9 

 hours after the last food. In nearly every one of the long series of 

 observations the minimum values occur at or near the end. An 

 exception to this is No. 131 in the observations on April 19-20, when 

 approximately the minimum was found 4| hours after the food. The 

 energy content of the food in this case was, however, but 50 calories. 

 Numerically the same conditions hold with regard to the observations 

 on March 11-12, 1916, with No. 136. It is probable, therefore, that 

 with as small an amount of food as 2 or 3 ounces of breast milk, with 

 an energy content of approximately 50 calories, the metabolism is 

 nearly basal at the end of 4 hours. With larger amounts of food the 

 stimulating effect may persist for 9 or 10 hours. 



