8 



can the collective ganglia be so many brains,* nor has the 

 head ganglion made out any case to be pre-eminently 

 such, f 



And if the supposition of a multiplicity of brains be thus 

 absurd, and the assertion of any one ganglion to be chief 

 amongst its fellows, and brain proper, be thus unsup- 

 ported, it would seem to follow, as of course, that insects 

 have, indeed, no centrum commune of sensation and intel- 

 ligence ; and if it be admitted that they are destitute of 

 this, to prove them in the largest possession of nerves, 

 would be of no avail. 



But, as the possession of a brain, or some equivalent to 

 a brain, by insects, may be still, by some, held not to have 

 been entirely disproved, let us now enquire into the second 

 condition required for the sentient life-, and direct our 

 attention to certain peculiarities of theNervous system, as 

 it has been latterly elucidated in man and the higher ani- 

 mals, in order to compare that nervous system with the 

 nerves of insects, and see if it be a probable doctrine that 

 they have nerves fitted for sensation. 



It is now generally admitted that in man and the higher 

 animals, there are two distinct orders of nerves, which not 

 only differ in their place of origin, but are subservient to 

 different uses. All physiologists now talk of nerves for 

 sensation and nerves for voluntary motion, in addition to 

 which two orders of nerves, some have thought that there 

 is a necessity for the admission of a third, to administer 

 lo the growth of the body, regulate the transition of food 

 into nourishment, and preside over the intestinal secre- 

 tions, and the defecation of the system. Take all three 



the other functions are so independent of that mind, that they 

 can be and are carried on without its cognizance. Mind, there- 

 fore, or one of the attributes of mind consciousness- is necessary 

 to feeling, which being in its very nature single, the corporeal seat 

 (so to speak) of feeling must be also single, that is, again, there can 

 be but one brain. 



* See Appendix (A). f See Appendix (B). 



