8 4 S 
ANIMAL HEAT. 
Numerous observations have been made, chiefly by Pfliiger and his 
pupils, upon the effect of changes in external temperature upon the 
respiratory exchange of animals in normal and abnormal conditions. 
The results of some of the most important experiments will now be 
given •} — 
Tempera- 
ture of Air. 
Intake of Oxygen. 
Output of Carbon 
Dioxide. 
co 2 
Oj 
Animal. 
Observer. 
4°-4 
210 - 7 grms. in 6 
hours. 
Man 
weighing 
Voit. 2 
6°-5 
206-0 
71 kilos. 
9°-0 
192-0 
14° -3 
155-1 
23°-7 
164-8 
26°-7 
160-0 
30° -0 
170-6 
7°-3 
1496-66 c.c. per hour 
and kilo. 
1203-44 c.c. 
o-so 
Guinea- 
pig- 
Colasanti." 
16° -9 
1086-8 
937-01 ,, 
0-86 
3°-64 
1856-8 
1564-8 ,, 
0-83 
Guinea- 
Finkler. 4 
26° -21 
1118-5 ,, 
1057-4 ,, 
0-94 
pig- 
-5° -5 
17 "48 grms. in 6 hours 
19-83 ,, 
Cat 
Herzog 
2°-0 
15-79 
17-87 ,, 
weighing 
Carl 
12° -3 
17-71 
17-63 ,, 
about 2-5 
Theodor. 5 
20°-l 
12-78 
14-34 ,, 
kilos. 
29°-6 
13-91 
13-12 „ 
-9°-0 
3016 c.c. per hour 
and kilo. 
Pigeon. 
Corin and 
VanBene- 
17°'5 
1141 „ 
den. 6 
It will be seen from the above table that the respiratory exchange 
decreases with a rise in external temperature, until a point about 35° 
is reached, when an increase in the metabolism occurs. 7 The response 
to a change in temperature is, in the case of small mammals, almost 
immediate. 8 Thus, within two minutes of a change from 30° to 18°, 
a mouse increased its output of carbon dioxide by 74 per cent. ; within 
one minute of a change from 33°'25 to 17°*5 the increase was 60 per 
cent. The response to an increase in temperature does not take place 
so quickly ; thus, within two minutes of a rise from 18° to 34°-5, 
the decrease in the output of carbon dioxide was 18 per cent. ; 
within one minute of a rise from 17° to 32°, the decrease was 5 
per cent. The power of maintaining a constant mean temperature is 
readily tested in this manner, as the following example will show 
(Pembrey) : — 
1 See also the preceding article on " Chemistry of Respiration." 
2 Ztschr. f. Biol., Miinchen, 1878, Bd. xiv. S. 57. 
8 Arch. f. d. ges Physiol., Bonn, 1877, Bd. xiv. S. 92. 
4 Ibid., 1S77, Bd. xv. S. 603. 
5 Ztschr. f. Biol., Miinchen, 1878, Bd. xiv. S. 51. 
6 Arch dc biol., Gand, 1887, tome vii. p. 274. 
7 See also Page, Joum. Physiol., Cambridge and London, vol. 
"Chemistry of Respiration," this Text-book, vol. i. p. 712. 
8 Pembrey, Joum. Physiol., Cambridge and London, 1894, vol. xv. p. 401 
"Chemistry of Respiration," this Text-book, vol. i. 
p. 228 ; and 
See also 
