INTRODUCTORY OBSERVATIONS, xl^ 



In the beginning of November, Redi opened 

 the fkull of a land tortoife, and excavated the 

 whole brain. The tortoife did not feem to fuf- 

 fer : it moved about as before, but groping its 

 way ; for the eyes foon Ihut after lofmg the 

 brain, and never Opened again. A flelhy inte- 

 gument formed, which covered the opening of 

 the fkull ; and in this ftate the animal lived until 

 May, that is, fix complete months. Spallanzani 

 deprived four frogs of the brain : two lived til! 

 the fifth day. He alfo deprived three newts oS 

 the brain : they fuffered violent convulfions ; 

 their eyes clofed ; they hardly moved from one 

 place to another ; and expired about the middle 

 of the third day. 



He cut the heart out of three newts : they 

 took to flight, leapt, fwam, and executed the 

 fame functions as before ; however, all died in. 

 forty-eight hours. Four frogs, deprived of the: 

 heart, kept their eyes open, and preferved the 

 ufe of their limbs. They furvived thirty-fixr 

 hours. 



Privation of thefe organs, and evenof thofefar 

 lefs important in the organic fyftem, would occa- 

 lion immediate death to innumerable animals. 

 But it does not appear that the tenacity of hfe is 

 uniformly dependent on the fame principle, or 



abfolutelj 



