ASPII \ 'XI A IN A LIMITED Q UANTITY OF AIR. 743 
differ in different individuals. In one case the hyperpncea became 
appreciable at about L2 per cent., and excessive at about 6 per cent." 
These observers also point out that the odorous substances arising 
from want of cleanliness of the body or the room, are also causes of the 
discomfort experienced in breathing the air of an overcrowded room. 
The causes of asphyxia in a limited quantity of air.— A 
warm-blooded animal confined in a limited quantity of air soon gives 
signs of discomfort ; it becomes restless, breathes more rapidly, and 
soon pants for breath. This stage is succeeded bv one during which 
the animal is quieter, breathes more slowly but more deeply ; it becomes 
less sensitive, and falls down ; agonising efforts are made to breathe, the 
nostrils are dilated, and the mouth is open. The animal now becomes 
unconscious, its pupils are dilated, it gives a few slight and irregular 
respirations, it is seized by convulsions, and then, after a slight pause, its 
limbs are stretched out with a convulsive shivering movement, its head 
is thrown back, and it dies. 
The general phenomena of asphyxia are described elsewhere in this 
work ; x here it is necessary to consider only the chemical changes in the 
air, the alterations they produce in the respiratory exchange of the 
animal, and how they cause its death. Upon these questions numerous 
experiments have been made. 2 
The duration of life in a limited quantity of air depends upon 
various conditions, such as the amount and temperature of the air, the 
nature and age of the animal. The following table of some of Paul 
Bert's experiments will illustrate the influence of some of the above con- 
ditions, and will show the composition of the air at the time of death : — 
Percentage Composi- 
tion of Air at the 
Animal. 
Tempera- 
ture of Air. 
Volume 
of Air. 
Duration of Life. 
time of Death. 
02. 
COs. 
Mammals — 
Cat, 1850 grms. 
■lb 
5000 C.c. 
25 min. 
3-4 
17-1 
Kitten. 5 (lavs old, 130 
15° 
1000 „ 
I| to '.i hrs. 
2-0 
16-6 
grms. 
Kitten, 24 hours old, 125 
11 
435 „ 
1 hr. 15 min. 
3-0 
14-S 
grms. 
Hedgehog, young, 115 
25 ; 
1500 „ 
1 hr. 15 min. 
4-0 
14-0 
grms. 
Dormouse, hibernating, 
12 3 
350 „ 
About 1 day 
2 - 2 
14-6 
50 grms. 
Rat, white, 115 grms. . 
14 3 
450 ,, 
32 min. 
3 
11-0 
125 ,, 
25 c 
1600 ,, 
Between 2 and 
3 hrs. 
2 - 2 
17-8 
,, ,, adult 
30°-35° 
2000 ,, 
20 min. 
11-8 
6-5 
,, three days old, 
25° 
100 „ 
More than 6 hrs. 
075 
17-0 
5 grms. 
Rabbit, young. 200 grms. 
25 ; 
6000 ,, 
Alive but insensi- 
ble after 6 hrs. 
1-9 
13-4 
Birds— 
Sparrow, 23 grms. 
16° 
300 „ 
1 hr. 
23 
133 
Finch, 25 grms. 
11° 
428 „ 
21 min. 
5-0 
12-4 
1 Article "Mechanism of Respiration," this Text-book, vol. ii. 
"Edwards, "De l'influence des agens physiques sur la vie," Paris, 1S24 ; Collard de 
