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CHAPTER IV. 



On the Agency of External Temperature in pro- 

 ducing Hybernation and suspended Animation. 



" In the multitude of books there was no where comfort or 

 knowledge, but vain promises, abuses, and many errors. The 

 cup of sloth hath tainted the schools with drowsiness, every one 

 being more willing to assent, than to search carefully. I there- 

 fore considered within myself, that the art of healing was a mere 

 juggle." VAN HELMONT. 



DR. ROGET maintains in a Treatise on Animal 

 Physiology, contained in the Library of Useful 

 Knowledge, that " Hybernation is a provision of 

 nature to preserve animals from the effects of a 

 temperature that would be fatal to them." And 

 Dr. Marshall Hall observes in an article on Hy- 

 bernation, contained in the Cyclopaedia of Ana- 

 tomy and Physiology, that " the lethargy of ani- 

 mals is not the effect of cold, but is a physiolo- 

 gical condition of the system, which differs from 

 ordinary sleep only in degree;" and that " the 

 true spinal or excito-motory system of nerves/' 

 (to which he refers the irritability or contracti- 

 lity of the muscles,) " retains all its energies." 

 What is still more remarkable, he maintains that 

 " the irritability of animals is inversely as the quan- 

 tity of their respiration, being greater in reptiles 



