106 FOOD JNGESTION AND ENERGY TRANSFORMATIONS. 



periods of the same day. The average carbon-dioxide production of 

 this subject over a period of approximately six years was 204 c.c. An 

 examination of the figures in the extreme right-hand column shows a 

 tendency for the carbon-dioxide production to be lower during the last 

 half of the series than during the first half. 



When the values for the oxygen consumption given in table 40 are 

 examined, it is seen that the discrepancy in the carbon-dioxide pro- 

 duction which was noted for the first period does not appear in the 

 oxygen values. Indeed, there is a possible tendency for the oxygen 

 consumption to increase slightly as the day goes on. The average value 

 for the first half-hour drawn from 8 periods is 239 c.c. ; those for the fifth 

 to the eighth periods are all 245 c.c. or over, with the last three per- 

 ceptibly higher. On the other hand, the average value for the whole 

 series of observations is 244 c.c., which does not indicate a trend toward 

 variation in oxygen consumption as the day progresses. As was the 

 case with H. L. H., variations from period to period on the same day 

 are frequently noted. 



The mean variation, like that for the carbon-dioxide production, is 

 small, which is indicative of a satisfactory technique. The values in 

 the extreme right-hand column show that in a period of six years there 

 was no apparent tendency for the oxygen to alter its value to any 

 great extent, but as the last three values are measurably lower than the 

 average, it may be necessary to limit the period of approximately 

 constant metabolism to the time between April 26, 1909, and May 22, 



1911, especially as but one value was obtained after June 5, 191 1. The 

 data in table 40 give no conclusive evidence, however, that a period 

 of six years is sufficient to alter materially the average metabolism of 

 this subject. 



EXPERIMENTS WITH J. K. M. 



The third subject was a former laboratory assistant, J. K. M. 

 Values for eight periods, i. e., from approximately 8 h 30 m a. m. to 12 h 

 30 m p. m., are recorded. The data for the carbon-dioxide production 

 are given in table 41 ; the general average for the entire series of obser- 

 vations, which is shown in the last line of the table, is 183 c.c. There 

 is no indication of a material change in the metabolism during the 

 forenoon, although wide variations occasionally appear from period 

 to period. The average values for each experiment, which are given 

 in the right-hand column, show that during the period from May 24, 



1912, to July 23, 1913, or one year and two months, there was no 

 general tendency for the carbon-dioxide production either to increase or 

 to decrease, as the values for the most part lie quite close to the gen- 

 eral average. The chief exceptions are the minimum value of 165 c.c. 

 on June 29, 1912, and the maximum value of 210 c.c. on May 24, 1912. 

 This latter value was obtained on the first day of experimentation, 

 when, owing to the novelty of the situation, the metabolism is usually 

 higher than on subsequent days. 



