110 ANIMAL INTELLIGENCE 
the woodchuck answered like a barometer to predict 
storms. In fact, I am satisfied that many wild animals 
have a delicate perception of meteorological conditions 
which man has not, and which, in a sense, makes them 
wiser than our science, and wiser than they know, for 
they act reflexly, as it were. Often my marmot would 
be heard in the night scraping the straw about him 
prior to a storm that did not reach us for many 
hours after. 
Marshall Hall laid it down as one of his principal 
conclusions that in hibernating animals “muscular 
irritability ” is increased. 
If the term reflex be substituted for muscular, I 
believe the conclusion is correct. I found, as a result 
of scores of trials, that when the marmot was hibernat- 
ing, he was more sensitive to slight stimuli, such as 
blowing on the hairs of the skin, than when merely 
sleeping. Plainly this was not acase of muscular 
irritability at all, but it does indicate that the reflex 
mechanism is more excitable, as it is, for example,in an 
animal under the influence of strychnine, and as it is 
in animals from which a portion of the cerebrum has 
been removed. 
It may be because the unconsciousness is so pro- 
found, z.e. the brain so far from its ordinary functional 
activity, for it is well-established that the brain in- 
hibits the spinal cord normally, to a certain extent. 
Apparently this increased reflex excitability must be 
to the advantage of a hibernating animal, for the cord 
and medulla oblongata are the parts of the nervous 
centres that especially preside over the functions of 
organic life, which are necessary to maintain a mere 
animal existence. 
All problems of a biological kind must ultimately be 
referred to cells, and so with this of hibernation. 
Indeed, it would seem that unicellular animals pass 
