INSECT SENSIBILITY. 169 



of a wasp in the pleasures of a peach, or that of a dragon-fly 

 in the discussion of its butterfly game. 



But there are other reasons more scientific, if not more con- 

 clusive, for supposing that the sensitivity of insects is inferior 

 to our own and that of other vertebrate and warm-blooded 

 animals, whose nervous system is altogether different. In the 

 latter, the nerves and spinal marrow are the roads by which 

 sensations travel to the brain (the common sensorium), the 

 detachment of which from the body deprives it of motion and 

 feeling ; whereas the nervous system of insects consists of a 

 double nervous chord, formed at intervals into knots or gang- 

 lions, from whence proceed, in pairs, principal nerves, with 

 branches distributed to every part of the frame.* 



The existence of any insect brain has been denied by Lin- 

 naeus and subsequent naturalists ; but Cuvier and Lamarck so 

 denominate the upper knot of the nervous chord, because dis- 

 tinguished by the sending forth of nerves to the principal 

 organs of the senses. The multiplied and detached centres of 

 sensation, thus furnished by the knots or ganglions, sufficiently 

 account for life and motion in the divided portions of insect 

 frames; also for their seeming to feel comparatively little 

 general pain from the loss of limbs, or even head. 



Last, not least, there is another reason, built on the moral 

 attributes of the Great Creator, for believing that the insect 

 frame is one of extreme sensibility to outward injury. Can 



* See Kirby's and Spence's Introduction to Entomology, p. 278. 



