Bauhaus-Universität Weimar

Titel:
The Cyclopaedia of Anatomy and Physiology, vol. 2: Dia-Ins
Person:
Todd, Robert Bentley
PURL:
https://digitalesammlungen.uni-weimar.de/viewer/image/lit25760/777/
HIBERNATION. 
769 
more susceptible of the influence of cold, in 
inducing sleep and the loss of temperature. The 
hedgehog, which awakes from its hibernation, 
and does not eat, returns to its lethargy sooner 
than the one which is allowed food. 
The respiration is very nearly suspended in 
hibernation. That this function almost ceases, 
is proved, 1st, by the absence of all detectible 
respiratory acts ; 2dly, by the almost entire ab¬ 
sence of any change in the air of the pneuma- 
tometer ; 3dly, by the subsidence of the tem¬ 
perature to that of the atmosphere ; and 4thly, 
by the capability of supporting, for a great 
length of time, the entire privation of air. 
1. I have adopted various methods to ascer¬ 
tain the entire absence of the acts of respiration. 
I placed bats in small boxes, divided by a par¬ 
tition of silk riband, the cover of which con¬ 
sisted of glass, and in the side of which a small 
hole was made to admit of placing a long light 
rod or feather under the animal’s stomach. The 
least respiratory movement caused the extremity 
of this rod to pass through a considerable space, 
so that it became perfectly apparent. 
Over the hibernating hedgehog I placed a 
similar rod, lixing one extremity near the ani¬ 
mal, and leaving the other to move freely over 
an index. During hibernation not the slightest 
movements of these rods could be observed, 
although they were diligently watched. But 
the least touch, the slightest shake immediately 
caused the bat to commence the alternate acts 
of respiration, whilst it invariably produced the 
singular effect of a deep and sonorous inspira¬ 
tion in the hedgehog. It is only necessary to 
touch the latter animal to ascertain whether it 
be in a state of hibernation or not: in the 
former case there is this deep sonorous inspira¬ 
tion ; in the latter, the animal merely moves 
and coils itself up a little more closely than 
before. After the deep inspiration, there are a 
few feeble respirations,and then total quiescence. 
The bat makes similar respirations without the 
deep inspiration, and then relapses into sus¬ 
pended respiration. 
2. As the acts of respiration are nearly sus¬ 
pended during hibernation, so are the changes 
induced in the atmospheric air. 
On January the 28th, the temperature of the 
atmosphere being 42°, I placed a bat in the 
most perfect state of hibernation and undis¬ 
turbed quiet, in the pneumatometer, during the 
whole night, a space of ten hours, from lh. 30m. 
to lih. 30m. There was no perceptible absorp¬ 
tion of gas. 
Having roused the animal a little, I replaced 
it in the pneumatometer, and continued to dis¬ 
turb it from time to time, by moving the appa¬ 
ratus. It continued inactive, and between the 
hours of lh. 20m. and 4h., there was the absorp¬ 
tion of one cubic inch only of gas. 
Being much roused at four o’clock, and re¬ 
placed in the pneumatometer, the bat now con¬ 
tinued moving about incessantly ; in one hour, 
five cubic inches of gas had disappeared. It 
was then removed. A further absorption took 
place of -8 of a cubic inch of gas. 
Thus the same little animal, which, in a state 
of hibernation, passed ten hours without respi¬ 
ration, absorbed or converted into carbonic acid, 
VOL. II, 
5-8 cubic inches of tixygen gas in one hour 
when in a state of activity. In an intermediate 
condition, it removed one cubic inch of oxygen 
in two hours and forty minutes. 
I repeated this experiment on February the 
18th. A bat, in a state of perfect hibernation, 
was placed in the pneumatometer, and remained 
in it during the space of twenty-four hours. 
There was now the indication of a very slight 
absorption of gas, not, however, amounting to 
a cubic inch. 
On February the 22d, I repeated this expe¬ 
riment once more, continuing it during the 
space of sixty hours; the thermometer de¬ 
scended gradually, but irregularly, from 41° to 
38°; the result is given in the subjoined table. 
External Absorp- Dura- 
Date 
Temperature. 
tion. tion. 
Feb. 22 
11 
P.M.. 
.....41° 
23 
11 
A.M. 
.....384.... 
•8____ 
12h 
11 
P.M.. 
•75____ 
12 
24 
11 
A.M.. 
*5.... 
12 
11 
P.M.. 
•75____ 
12 
25 
11 
A.M., 
•6____ 
12 
3-4 
60 
From 
this 
experiment it appears that 
34 
cubic inches of oxygen gas disappeared in sixty 
hours, from the respiration of a bat in the state 
of lethargy. It has been seen that in a state of 
activity, an equal quantity of this gas disap¬ 
peared in less than half that number of minutes. 
The respiration of the hibernating bat descends 
to a sub-reptile state ; it will be seen shortly 
that the irritability of the heart and of the mus¬ 
cular fibre generally, is proportionably aug¬ 
mented. 
In this experiment it is probable that the 
lethargy of the animal was not quite complete. 
Should the temperature of the atmosphere fall, 
and continue at 32°, I shall again repeat it 
under these circumstances. The respiration 
will probably be still more nearly suspended. 
It is important to remark, that the registra¬ 
tion of the quantity of absorption in these expe¬ 
riments was not begun until several hours after 
the animal had been inclosed within the jar of 
the pneumatometer, so that the absorption of 
the carbonic acid always present in atmospheric 
air was excluded from the result. 
It may be a question whether the slight 
quantity of respiration I have mentioned be 
cutaneous. The absence of the acts of respira¬ 
tion would lead us to this opinion. But it may 
be observed, that these acts have not been 
watched, and can scarcely be watched continu¬ 
ously enough, to determine the question of 
their entire absence. Some contrivance to as¬ 
certain whether the rod has moved along the 
index during the absence of the observer would 
resolve every doubt upon this interesting point. 
And I think it right to remark, that after the 
apparent total cessation of respiration, as ob¬ 
served by the means which have just been de¬ 
scribed, there is probably still a slight diaphrag¬ 
matic breathing. I am led to this conclusion, 
by having observed a slight movement of the 
flank in a favourable light, unattended by any 
motion of the thorax or epigastrium. 
3. Much precaution is required in ascertain- 
3 E
        

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