INFLUENCE OF AGE. 803 
for muscular work. 1 Daily variations in the output of carbon dioxide 
and in the intake of oxygen have been observed by Prout, Pettenkofer 
and Voit, Fredericq, 2 and others; these variations in metabolism more 
or less correspond with those observed in the temperature, and will be 
found discussed more fully in another part of this work. 3 
Best in bed throughout the day dues not abolish the daily variation; 
it is still present, although modified, in cases of disease, attended or 
unattended by fever ; the morning rise still takes place even when light 
is excluded (Ogle). 
In animals, daily variations in temperature have also been observed, 
but upon this point there are few exact observations taken throughout 
the day and night. Strecker, 4 from observations upon 150 horses, found 
the average temperature between 6.30 a.m. and 8 a.m. to be 37°"9, that 
between 5 p.m. and 6.30 p.m. to be 37°"93 ; but the minimum was 37°'2 
and the maximum 38" - 6. In the case of oxen, Eobertson 5 found the 
average morning temperature 38°"7, the evening temperature 38 3 '9 ; in 
the cat the minimum is 37 "8 at 7 a.m. and the maximum 39°"08 at 
10 p.m. (Bidder and Schmidt). 6 Hunter states that the temperature of 
an ass was o- 5 higher in the evening than in the morning. According 
to the observations of Siedamgrotzky, 7 the maximal daily temperature in 
horses was 38°'2 at 6 p.m., the minimum 37°'5 at 4 a.m.: in a cow the 
maximum was 39 0- l at 5 P.M., and the minimum 38°'7 at midnight. 
Corin and Van Beneden s have observed the daily variation in pigeons, 9 
and find that the minimum is at 4 A.M. ; that from this time to 8 a.m. 
there is a rise, then a fall to noon, followed by a rise to the maximum 
at 4 p.m. ; the daily variation amounts to 2°"2. In the case of horses, 
Hobday 10 finds that the rectal temperature at 10 a.m. is 37 c- 6, and 37°"9 
at 5 P.M. : in the case of the rabbit, cat, and dog, Carter u has shown that 
there is a distinct rhythm of temperature, the maximum occurring in 
the evening (7-11 p.m.) and the minimum in the morning (7-11 a.m). 
We may conclude that the daily variation in temperature is one of 
the features of a corresponding variation in the activity of the tissues of 
the body, as shown by the rate of the contraction of the heart, the 
frequency of respiration, the intake of oxygen, the output of carbon 
dioxide, the discharge of urea, and the capacity for muscular work. 
The influence of age.— The temperature of newly-born infants and 
animals is generally equal to, or even slightly higher than, that of their 
parents, but it is much less stable, and is liable to much greater varia- 
tions. 
Edwards 12 found that the temperature of newly-born pups, kittens, 
and rabbits fell when they were removed from their warm surroundings, 
and continued to fall until it reached a point a few degrees above the 
1 Patrizi, Arch. itai. de bioL, Turin, 1892, tome xrii. p. 134. 
2 Prout, Ann. Phil.. London, 1813, vol. ii. p. 330; vol. iv. p. 331 : Pettenkofer and 
Voit, Ztschr. f. BioL. Munchen, 1866, Bd. ii. S. 459 ; Fredericq, Arch, dc bid., Gand, 
1882, tome iii. p. 729. 
3 "Chemistry of Respiration," this Text-book, vol. i. p. 721. 
4 Ellenberger. " Vergleichende Physiologie der Haussaugethiere" 1892, Bd. ii. Th. 2, S. 81. 
5 Veterinary Journ. , London, 1885, vol. xx. p. 311. 
G "Die Yerdauimgssafre und der Stoffwechsel," Leipzig, 1852, S. 346. 
7 Deutsche Ztschr. f. Thiermed., Leipzig, 1875, Bd. i. S. 87. 
8 Arch, dc bioL, Gand, 1887, tome vii. p. 265. 
9 See also Chossat, Mem. Acad. d. sc. de I' Inst, de France, Paris, 1843, tome viii. p. 540. 
10 Journ. Com}). Path, and Therap., Edinburgh and Loudon. 1896, vol. ix. p. 286. 
11 Journ. Xerv. and Merit. Bis., N.Y., 1890, vol. xvii. p. 7-2. 
12 "De l'influence des agens physiques sur la vie,'' Paris, 1S24. 
