1898.] on Instinct and Intelligence in Animals, 675 



other hand those resulting from the condition of the bodily organs, 

 taking the form of a felt craving for their appropriate exercise. These 

 co-operate to throw the brain into a state of unstable equilibrium, or 

 neural strain, which is relieved by outgoing streams of nervous energy. 

 And these in turn fall into two groups : first, an orderly set of 

 discharges to the voluntary muscles concerned in behaviour; and 

 secondly, a more diifuse group of discharges to the heart, resj)iratory 

 api)aratus, digestive organs, glands and vascular network. In so far as 

 these are outgoing discharges, they do not directly affect consciousness. 

 But there quickly returns upon the sensorium an orderly group of 

 incoming messages from the motor apparatus concerned in instinctive 

 behaviour, and a more indefinite group from the heart and other 

 visceral organs. The former gives the well-defined consciousness of 

 activity, the latter the relatively ill-defined feelings which are classed 

 as emotional. But so swift is the back-stroke from the body to the 

 brain, that, ere the instinctive behaviour is complete, messages from 

 the limbs — and, under the appropriate circumstances, from the heart 

 — that is to say, of both instinctive and emotional origin — begin to 

 be operative in consciousness ; and the final stages of a given per- 

 formance may be guided in the light of the experience gained during 

 its earlier stages. 



The exact manner in which consciousness exercises its guiding 

 influence is a matter of speculation. Perhaps the most probable 

 hypothesis is that the central hemispheres are an adjunct to the rest 

 of the central nervous system, and exercise thereon, by some such 

 mechanism as the pyramidal tract in the human subject, a controlling 

 influence. Given an hereditary ground plan of automatic and in- 

 stinctive responses, the cerebral hemispheres may, by checking here 

 and enforcing there, limit or extend the behaviour in definite ways. 

 In any case, from the psychological point of view, their action is 

 dependent on three fundamental properties : first, the retention of 

 modifications of their structure ; secondly, difierential results accord- 

 ing as these modifications have pleasurable or painful accompaniments 

 in consciousness ; and thirdly, the building of the conscious data, 

 through association, into a system of experience. The controlling 

 influence of this experience is the essential feature of active intelli- 

 gence. Or, expressed in the almost obsolete terminology of the older 

 psychology, intelligence is the faculty through which past inexperi- 

 ence is brought to bear on present behaviour. 



Professor Stout, whose careful work in analytical psychology is 

 well known, has done me the service of criticising, in a private com- 

 munication, my use of the phrase " past experience," urging that 

 present experience is not less important in determining behaviour 

 than that which is past, and which can only be operative through its 

 revival in memory. The criticism is valid in so far as it shows that 

 I have not been sufficiently careful to define what I mean by past 

 experience. But I certainly had in mind, though I did not clearly 

 indicate, the inclusion of what Mr. Stout regards as present ex- 



