XXIX.] THE PHYSIOLOGY OF MIND. 23 



appear to be purely reflex and insentient ; these pass, by 

 indistinguishable gradations, into consensual action ; so 

 that, at its commencement in the animal scale, sensation 

 appears not to exist alone, but solely as the guide to mus- 

 cular action. 



The nervous mechanism described above is all that insects 

 insects, or any other invertebrate animals, are known to thil*' °^ ^ 

 possess. Their highest nervous organs consist of the 

 nerves and ganglia of sense and motion, and their highest 

 nervous functions consist in sensation, and the direction of 

 motor actions by sensation. This at least is generally 

 true, but it appears difficult to believe that ants and with some 

 spiders have not some dawnings of conscious intelKgence, excep- ° 

 like that of the higher animals. For the most part, how- ^^°^^- 

 ever, the instincts of insects, wonderful as they are, consist 

 in consensual, or sense-directed, actions, guided by uncon- 

 scious vital intelligence,^ kindred rather to the organizing 

 intelligence which adapts the bodily structures for their 

 functions, than to the conscious mental intelligence of 

 man. Especially is this true of the cell-building instinct 

 of the bee and the wasp ; it cannot be supposed that those 

 insects understand the geometry of the hexagon, and the 

 unvarying perfection of their work is alone enough to ex- 

 clude the idea of an intelligence which works in any degree 

 like that of man. 



If some insects have a vestige of conscious intelligence, 

 its seat must be in the sensory ganglia. This would in- 

 volve no great anomaly, for motor, sensory, and mental 

 functions, including those of instinct, are much more 

 variable between species and species than are the functions 

 belonging to the inorganic life. Besides, the sensory 

 ganglia of all insects appear to be the seat of perception : 

 I mean the perception of external objects, as external ; 

 which, as I shall have to show farther on, I believe to be a 

 rational function, though the reason is unconscious of 

 itself. Leaving the problematical subject of the con- 

 sciousness of insects and spiders, we now go on to the 

 consciousness of the Vertebrata, and especially of man. 



1 See the chapter on Intelligence (Chap. XXVII.). 



