78 STELLA BURNHAM VINCENT 



from one or both of the wrong runways. In the end many of 

 the unnecessary associations dropped out and those which 

 remained became more and more automatic in character. 



In this discussion there has been an effort made to preserve 

 the distinction, which some forget," between the acquisition of 

 the act and the perfected reaction and the associations have 

 been treated in such detail in order to show the real complexity 

 of the problem and the great individuality of the reactions. 

 Perhaps sufficient emphasis has not been laid on the rejected 

 associations or at least those which finally sloughed off, as those 

 of position, preferential or associated with previous successes, 

 and the differing degrees of abihty to carry the controlling 

 association back regularly in time and space from the door to 

 the plate, from the plate to the surface of the walls and from 

 the walls near the plate to the walls at the entrance. 



Just what mental stuff this associative memory process is 

 carried on with it is difficult to say. Granting that the sense 

 experience is somewhat similar, an argument from structure of 

 course, why not admit it to be comparable to such very simple 

 human experiences. We may well rebel against the idea that 

 rats possess visual images such as ours when they have such 

 very poor visual organs, or against ideas in the human sense; 

 but something certainly is carried over here which is not incor- 

 porated directly in the stimulus. Perhaps in our efforts not to 

 become anthropomorphic we have swung too far the other way. 

 There seems to be evidence of comparison, there seems to be 

 memory of distinct sense experience. A belief which is shared 

 by many is that all human imagery has in it real sensory ele- 

 ments and that revival involves periphery as well as center, the 

 whole arc in other words, although we fully reaUze that our 

 present knowledge of neurological structure does not confirm 

 this. There are, however, some facts which might seem to 

 support the contention. 



The perfection of neurological technique is giving us increas- 

 ing knowledge of the variety of functional fibers in the nerve 

 trunks and makes us feel that there are still unknown possi- 

 bilities in these. The centrifugal fibers which are found in some 

 of the aff'erent nerve trunks, the optic for example, are thought 

 by the biologists Cajal,^* Duval, Lenhossek, Roux and others 



^' Ramon, y Cajal, S.: Histologie du Systeme Nerveux, 1911, p. 366. 



