406 General Notes. [April, 
cases a voluntary act. Some of the observations on animals con- 
fined in our laboratory for the purpose of study, may throw more 
light on this subject. These animals are all well known species, 
and our aim is usually to keep them in surroundings as nearly 
like their natural habitations as possible. The temperature can- 
not, in the single room at present devoted to this use, be kept at 
a degree which will suit the habits of all of them, but the effects 
of its change on each is noted. 
A number of frogs (Rana halecina) were placed in a closed 
glass case, with growing plants to study the balancing effect of 
their respiration. Plants and frogs seemed to thrive excellently, 
and during the four months trial, the temperature being kept at 
. about 70° F., the latter showed no evident signs of hibernation, 
though the case stood in front of a window against which the 
snow was often falling. To observe the effect of a lower tempera- 
ture, the case was moved to a cooler place (40°), and immediately 
the frogs, using their front legs like dogs, dug under the moss and 
stones, and remained out of sight until the former temperature 
was renewed. Similar experiments tried with salamanders, snakes, 
toads, houseflies and hornets, revealed at once a desire to hide 
during the lower temperature, but a complete absence of any 
such tendency when the normal degree of heat was preserved. In 
every one of these cases and a number of others, hibernation 
seemed to be forced. If the temperature was lowered, and they 
were at the same time prevented from burying themselves, they 
gradually became stiff and lifeless, but could in every case tried, 
except the last two mentioned above, be resuscitated upon the 
application of heat. 
uring this last fall a scorpion, shipped from the South in a 
_bunch of bananas, was subjected to like treatment with the same 
results. When cold it was so helpless that it could be handled 
with impunity; but when its box was placed near the fire, it 
id dart about with elevated tail in the manner peculiar to 
itself. 
With some of our animals experiments have given different re- 
sults. A wood-tortoise, though given a warm corner near the 
fire, could not be persuaded to pass the winter above ground. It 
e exhibited very evident signs of uneasiness as the snow came, and, 
~as soon as material was furnished, burrowed out of sight. The 
d inaction. Their den was placed by a window on the 
de of the building. Their food has remained untouched 
