206 OUT OF DOORS. 



cold and exposed spot, where they would be influenced 

 by the increasing chill of the weather. But it is found, 

 after a long course of experiments, including a most 

 valuable series by Dr. Marshall Hall, that the effect of 

 cold upon a hibernating animal is twofold; it first 

 awakes the creature from slumber, and then kills it. 



During the time of its slumbers the extreme torpidity 

 of the vital organs is most curious, while the external 

 portions seem to acquire a proportionate irritability, a 

 phenomenon which is partially seen even in ourselves 

 during ordinary sleep. If, for example, a hedgehog 

 while in the torpid state be touched, it partially uncoils, 

 gives a peculiar deep grunt, and again curls itself up. 

 The bat, if touched while in this strange sleep, will 

 wriggle about like an injured worm, while the very 

 same touch would have no perceptible effect upon it 

 when awake. Indeed, the hibernating creature seems 

 to pass, for a time, into a lower state of being, as far as 

 its mere animal characteristics are concerned ; and the 

 bat, the highest of our British mammals, becomes 

 scarcely higher in its organisation than a toad or a 

 frog. 



Instead of keeping up a high temperature, as is the 

 case while it is awake, it actually becomes colder than 

 many cold-blooded animals ; the temperature of the 

 body exactly following that of the surrounding atmo- 

 sphere, the heat of the surface being about half a degree 

 higher, and that of the vital organs about three degrees ; 

 so that when a thermometer hanging beside the animal 



