KOTE-BOOK OF A NATURALIST. 2o3 



cleaned the cavity out. The animal was then set at 

 liberty, but instead of dying or remaining motionless, it 

 groped its way about freely as its inclination directed, 

 without the aid of sight ; for when the animal was de- 

 prived of its brain it closed its eyes, which it never opened 

 afterwards. The wound was left open, but skinned over 

 in three days, and the tortoise continued to go about till 

 the middle of May, when it died. On examining the 

 skull, the cavity which had contained the brain was found 

 empty and clean as it had been left, with the exception 

 of one small, dry, black clot of blood. 



But this was not a solitary instance. Many other land- 

 tortoises w^ere subjected to the same treatment in Novem- 

 ber, January, February, and March. The result was 

 similar, with some exception ; for some moved about 

 freely, but others, though they showed that they were 

 alive by other motions, did not. Freshwater-tortoises, 

 when made the subjects of the same experiment, acted 

 like the others, but did not live so long. But Redi had 

 a notion, that if the marine tortoises were deprived of 

 their brain they would live for a very long time; for hav- 

 ing received a turtle which was very much wasted and 

 faint, he opened its skull and treated it in every respect 

 as he had treated the land-tortoises, and, emaciated as it 

 was, it lived six days after the operation. 



Redi proved the enduring vitality of these reptiles by 

 a more decisive experiment. In the month of Novem- 

 ber he cut off the head of a large tortoise ; the headless 

 animal did not expire till twenty-three days had elapsed. 

 This decapitated existent did not, indeed, move about 

 like those which had only been robbed of their brain ; 

 but when any mechanical stimulus, such as pricking or 

 poking, was applied to the anterior or posterior extremi- 

 ties, the headless trunk drew them up with considerable 

 liveliness, and exhibited many other motions. To free 

 himself from all doubt as to the vitality of these animals 



