THE METABOLISM OF THE BODY. 463 
the equator, and the same may be said of the effect of the | 
temperature of a warm summer day as compared with a cold 
winter one. The wonder is that, considering the external 
temperature, the variation is so light. 2. Starvation lowers | 
the temperature, and the ingestion of food raises it slightly, : 
the latter increasing, the former decreasing, the rate of the 
metabolic processes. 3. Age has its influence, the very young'| 
and the very old, in whom metabolism (oxidation) is feeble, | 
having a lower temperature. This especially applies to the 
newly-born, both among mankind and the lower mammals; 
and, as might be supposed, the temperature falls during 
sleep, when all the vital activities are diminished. The same 
remark applies with greater force to the hibernating state 
of animals. 4. Very interesting are the fluctuations of tem- 
perature occurring daily, as shown by the curves of Fig. 
87.5°. 
~ | 
Weta ae StI 
SY 
bs pid — aN, 
37 v4 N 
L AN 
A 
va SETK 
5. hl AA. 
36-5 > i 7 
— 
ji S ST 
[ a 
wt! 
7° 8 9 10 HN 1 1 2 8 4 5 7 8 9 1 W121 2°38 4 6 
Morning. Mid-day. Evening. Night. Morning. 
Fic. 340.—Variations of the daily temperature in health during 24 hours: L., after Lieber- 
meister ; J., after Jiirgenson (from Landois). 
340. It will be noticed that the period of greatest bodily 
warmth is between about four and seven o’clock in the after- 
noon and the minimum temperature between two and five in 
the morning. 
It will be inferred, from the facts and figures already cited, 
that different kinds of food have considerably different capacity 
for heat production. The following estimates will still further 
tend to illustrate this: 
Animal diet produces.............-.55 2,779,524 heat-units ( 
Food free from nitrogen............... 2,059,500 “ is 
IMG xGd Geb oss suc us wy udeawereeercones 2,200,200 “ « 
Absence of food, the heat amounts to.. 2,012,816 “ ee 
It is well known that a man when working not only: 
feels warmer, but actually produces more heat. The fol-’ 
lowing figures will give (approximately) some definite in- 
