434 INFLUENCE OF INANITION ON METABOLISM. 



activity ;md conditions which would otherwise obtain during the ordinary rest 

 experiment. The differences between the output during the day time and that 

 of the night are, it is true, not sufficiently great to warrant an assertion that 

 there is a positive increase in the water vaporized from the actual body surface 

 of the man during the day, but making due allowance for the vaporization from 

 the bed clothing, which was in these experiments weighed but once each 24 

 hours, the evidence still points towards a slightly greater elimination of water- 

 vapor during the day period. The increased respiration rate of the day, 

 thereby causing a greater ventilation of the lungs and a greater vaporization 

 of water, would certainly imply an increased water- vapor output during this 

 period. 



Influence of the ingestion of food. In the few food experiments which are 

 here reported, the data are also given for the comparison of the output of 

 water-vapor during the different periods of the day. While the number of 

 individual experimental days from which the data are drawn is less than 

 half of those of the fasting experiments, the number is sufficient to average 

 and give general information regarding the distribution of the water-vapor 

 output for the day. The differences are much less than in the fasting experi- 

 ments. A close examination of the table shows that the water of respiration 

 and perspiration on the second and third days of experiment No. 70 was 

 abnormally high in practically all periods. On these two days the subject was 

 evidently in a slightly febrile condition as an examination of the body tempera- 

 ture recorded on page 314 will show. While the data are too meager to draw 

 definite conclusions, they may indicate that slight increases in body tempera- 

 ture affect in a marked degree the elimination of water-vapor, and from the 

 results upon these two days, it would appear that the greatest factor, other 

 than perhaps excessive muscular activity, in determining the water-vapor 

 output of resting man is body temperature. It must be borne in mind, that in 

 no instance in these experiments were the quantities of food appreciably more 

 than enough for maintenance. The food was, generally, in the form of milk 

 and similar products given in small amounts and at frequent periods through- 

 out the day. 



A comparison between the food experiments and the fasting experiments may 

 also be made by noting the variations in the water-vapor elimination in the 

 food experiment immediately following a fast. Thus, in comparing experi- 

 ments Nos. 71 and 72, 73 and 74, and 75 and 76, such an inspection shows 

 that, although the water-vapor output is by no means as large on the first day 

 with food as on the first day of fast, it is in general somewhat greater than on 

 tbe last day of fast. Thus, on the seventh day of experiment No. 75, the 

 water-vapor output during the period from 7 a. m. to 9 a. m. was 55.1 grams 

 and on the next day, namely, the first day of experiment No. 76, the output 

 was 57.2 grams. On the seventh day of fasting for the second period it was 



