THE DOCTRINE OF HUMAN AUTOMATISM. 269 



tion. Taking up a suggestion thrown out by Mr. Grainger, I was 

 myself led to re-examine, under this new light, the facts previously 

 ascertained in resrard to the structure and actions of the nervous 

 system of invertebrate animals ; with the result that these facts 

 seemed to me not only to justify, but to require, the acceptance 

 of the doctrine that every separate ganglion of the ventral cord of 

 insects, centipedes, etc., is an independent centre of reflexion, the 

 function of the cephalic ganglia (which are chiefly, if not entirely, 

 the centres of the nerves of special sense,) being to harmonize and 

 direct their activity. This, again, now seems to be so self-evident 

 a proposition as to need no demonstration ; yet it had, like the 

 doctrines already summarized, to fight its way to general recog- 

 nition ; and though accepted by most British physiologists, it 

 seems not to have been known on the Continent until the publica- 

 tion, four years subsequently, of the classical memoir " On the 

 "Nervous and Circulatory Systems of the Myriapoda"(/%/A?^^////<ra/ 

 Transactions, 1843), ^^ which Mr. Newport gave in his adhesion 

 to it. 



The application of the doctrine of reflex action to insects gave 

 a definite physiological basis for the doctrine of instinct. All who 

 had carefully studied the remarkable habits of this class of animals, 

 especially those of the social Hymenoptera, had been led to recog- 

 nize their essentially automatic character; as specially indicated (i) 

 by the almost invaria])le uniformity with which they are performed 

 by all the individuals of the same type ; (2) by the perfection with 

 which they are performed from the very commencement of the life 

 of the imago ; and (3) by the impossibility, in many cases, of any 

 training or guidance having been derived from parental experience, 

 in the construction of habitations, the collection and storing up of 

 food for the larvae, and the like. Such actions can only be attri- 

 buted to an innate or congenital tendency to particular " modes 

 of motion" of the nervous system, dependent upon its mechanical 

 arrangements ; and to whatever extent insects learn from their 

 own experience, or have the power of intentionally adapting .their 

 ordinary constructive operations to new conditions * — a question 



• The account given by Mr. Bolt in his Naturalist in Nicarai^ua of the 

 adaptations made by ants, under contingencies brought about by human 

 agency, and but little likely to have arisen under natural conditions, seems 



