WHAT I SAW IN AN ANTS NEST. 343 



matic" powers and ways, even of higher animals, to dogmatise 

 regarding the acts of lower animals, but we may safely 

 assume that one apparent ground of distinction between 

 instinct and reason may be found in the common incom- 

 petence of instinct to move out of the beaten track of 

 existence, and in the adaptation of reason, through the 

 teachings of experience, to new and unwonted circumstances. 

 Let Dr. Carpenter, quoted in a previous paper, speak as an 

 authority on such a subject. " The whole nervous system of 

 invertebrated animals, then, may be regarded as ministering 

 entirely to automatic action ; and its highest development, as 

 in the class of insects, is coincident with the highest mani- 

 festations of the ' instinctive ' powers, which, when carefully 

 examined, are found to consist entirely in movements of the 

 excito-motor, and sensori-motor kinds. (The terms ' excito- 

 motor ' and ' sensori-motor ' are applied to nervous actions 

 resulting in movements of varying kinds, and produced by 

 impressions made on nervous centres, but without any neces- 

 sary emotion, reason, or consciousness. ) When we attentively 

 consider the habits of these animals, we find that their actions, 

 though evidently adapted to the attainment of certain ends, 

 are very far from evincing a designed adaptation on the part 

 of the beings that perform them. . . . For, in the first place, 

 these actions are invariably performed in the same manner by 

 all the individuals of a species, when the conditions are the 

 same ; and thus are obviously to be attributed rather to a 

 uniform impulse than to a free choice, the most remarkable 

 example of this being furnished by the economy of bees, 

 wasps, and other ' social ' insects, in which every individual 

 of the community performs its appropriated part with the 

 exactitude and method of a perfect machine. The very 

 perfection of the adaptation, again, is often of itself a suffi- 

 cient evidence of the unreasoning character of the beings 

 which perform the work ; for, if we attribute it to their own 

 intelligence, we must admit that this intelligence frequently 

 equals, if it does not surpass, that of the most accomplished 

 Human Reasoner." 



