THE ZOOLOGIST 



No. 832.— October. 1910. 



MENTAL POWERS OF ANIMALS. 



By P. T. L. Dodsworth, F.Z.S. 



To a student of Natural History nothing is perhaps more 

 interesting than to observe the display of mental and other 

 powers by animals. In many instances it is exceedingly difficult 

 to distinguish whether a particular action is the result of 

 instinct, or that of reason, and at the outset it will be as 

 well to understand clearly the difference between instinctive and 

 rational actions. "Instinct," says Eomanes, "is a generic 

 term comprising all those faculties of mind which lead to the 

 conscious performance of actions that are adaptive in character, 

 but pursued without necessary knowledge of the relation between 

 the means employed and the ends attained. We must, how- 

 ever, remember that instinctive actions are very commonly 

 tempered with what Pierre Huber calls ' a little dose of judg- 

 ment or reason.' But although reason may thus in varying 

 degrees be blended with instinct, the distinction between the 

 two is sufficiently precise ; for reason, in whatever degree pre- 

 sent, only acts upon a definite and often laboriously acquired 

 knowledge of the relation between means and ends. Moreover, 

 adjustive actions due to instinct are similarly performed by all 

 individuals of a species under the stimulus supplied by the same 

 appropriate circumstances, whereas adjustive actions due to 

 reason are variously performed by different individuals. Lastly, 

 instinctive actions are only performed under particular circum- 

 stances which have been frequently experienced during the life- 

 2ool.4thser.vol. XIV., October, 1910. 2 F 



