7io 
CHEMISTR Y OF RESPIRA TION. 
Weight. 
Oxygen , Carbon Dioxide 
per Kilo, and per Kilo, and 
Hour. Hour. 
C0 2 
O2 
Nitrogen 
discharged Tempera- 
per Kilo. ture. 
and Hour, j 
Remarks. 
Grms. 
3 lizards, 68-5 
2 ,, 42 
3 „ 62 
Grms. C.c. ! Grins. C.c. 
0-0246 17-2 : 0-025 12'6 
0-0646 45-2 0-063 32*3 
0-1916 134-0 0-199 100-77 
•73 
•71 
•75 
C.c. 
5732 7°-3 
1-905 14°-8 
2-49 23°-4 
Hibernating. 
Half awake. 
Awake and well ; 
fed for a month. 
There are, however, several conditions which prevent these results 
from being considered comparable ; the hibernating T animal has a very 
low respiratory exchange, even when the external temperature is higher 
than 7 0, 3 ; in the last experiment the food would increase the respira- 
tory exchange ; the observations were made at intervals of several 
months, and are complicated by the large discharge of nitrogen, which 
is probably to be attributed to an error of experiment. 2 
Biitschli 3 showed that the respiratory exchange of insects varied in 
the same direction as the temperature of their surroundings. 
The most complete series of observations appear to be those of 
Schulz 4 upon the edible frog (Puma esculenta). The following table 
gives his chief results, obtained upon frogs in summer : — 
Temperature 
of the Respiration 
Chamber. 
Temperature 
of Frog. 
COz-Output 
per Kilo, and Hour. 
C.c. at 0° and 760 Mm. 
C02-output 
per Kilo, and Hour 
in Grms. 
o°-o 
r-o 
4-31 
0-0084 
0°-25 
i°-o? 
6-097 
0-0119 
0°-8 
l°-5 
7-50 
0-0147 
6°-l 
6° -4 
34-17 
0-0672 
15°-8 
15°-4 
35-30 
0-0694 
l7°-0 
15°-2 
41-83 
0-0822 
25°*5 
25° -0 
76-26 
0-1499 
25°-5 
25°-3 
86-75 
0-1706 
33°-0 
33° -0 
279-40 
0-5495 
33°-2 
33°-l 
314-53 
0-6179 
34°-2 
33°-5 
340-48 
0-6696 
35°-0 
34° -0 
325-05 
0-6392 
It is to be noted that in Schulz's experiments the frogs were kept in 
the warm or cold surroundings until their temperature was equal to 
that of the air, so that the results are strictly upon frogs at different 
temperatures. The response of a frog, as shown by its temperature and 
respiratory exchange, to a change of external temperature is very slow, 
and for this reason observations upon the metabolism of cold-blooded 
animals can only be properly compared when the temperature of the 
animal and that of the air are known. The above results show that at 
temperatures a degree or two above zero the output of carbon dioxide 
1 See "Animal Heat," this Text-book, vol. i. 
2 See also Pfluger, Arch. f. d. ges. Physiol., Bonn, 1877, Bd. xiv. S. 73. 
3 Arch. f. Anat., Physiol., u. ivissensch. Med., 1874, S. 348. 
4 Arch. f. d. ges. Physiol., Bonn, 1877, Bd. xiv. S. 78. 
