262 NATURE STUDIES. 



animals is in itself so wonderful that the inexperienced 

 might well believe in any marvels resulting from an 

 extension of the hibernating process. It has been 

 well said that if hibernation had only been recognised 

 among cold-blooded animals, its possibility in the 

 case of mammals would have appeared inconceivable. 

 Possibly in that case the first recognition of the com- 

 plete hibernation of the bat and hedgehog would have 

 been received with as little respect as the wonderful 

 Australian discovery, though one case is, we know, 

 not only possible, but actually existent, whereas the 

 other is not consistent with scientific possibilities. 

 For no one who understands what hibernation really 

 is will for a moment confound it with the form of 

 insensibility imagined by the inventor of this hoax. 

 The bat and the hedgehog resign themselves to torpor 

 when the insects disappear on which they live while- 

 their active life continues. The breathing becomes 

 slower and slower, and at last ceases altogether. The 

 heart beats more and more slowly, more and more 

 feebly, but it never ceases altogether to pulsate. If it 

 did, life would pass away. The chemical changes on 

 which animal heat depends cease with the cessation of 

 respiration. But life is still preserved, though only 

 passive or latent life, because the heart's fibre, excited 

 to contract by the carbonised blood, continues slowly 

 to propel the blood through the torpid frame. Thi& 

 slow circulation of venous blood continues during the 

 whole period of hibernation. It is the only vital act 

 which can be recognised, and the marvel is great that 



