PHYSIOLOGY. 259 



communicated, through the medium of nerves, to 

 a common sensorium, though the latter was denied 

 to insects by Linnaeus and other eminent natu- 

 ralists. Common sensation, however, does not 

 reside in the brain alone of insects, as in that of 

 warm-blooded animals, but in the spinal marrow 

 also ; hence it is that bees and many other insects 

 exhibit signs of sensation after their heads have 

 been severed from their bodies. Some insects 

 exhibit these for a long time afterwards, the wasp 

 for instance ; L YON NET informs us that he has 

 seen motion in the body of a wasp, three days 

 after its division from the head ; and I have known 

 several instances of its inflicting wounds with its 

 sting, at least four-and-twenty hours after the 

 separation. The severed body will not only 

 move but walk, and sometimes even fly, at first 

 almost as actively without the head as with it. 

 The penetrating genius of LORD BACON afforded 

 him such illumination upon this subject, as to 

 enable him to approach very near to what is at 

 this day regarded as a correct statement of the 

 cause of this protractedvitality in mutilated insects. 

 "They stirre," says he, "a good while after their 

 heads are off, or that they be cut in pieces ; which 

 is caused also for that their vital spirits are more 

 diffused throughout all their parts, and lesse con- 

 fined to organs than in perfect creatures." 



That insects have a real sensorium or brain, 



