2 D. B. CASTEEL 



visually appreciating these slight differences in form and mark- 

 ing? Are they capable of using them as signs of specific iden- 

 tity? Whether or not such visual discrimination, if it exists, is 

 partly or entirely subordinate to ability to distinguish through 

 the sense of smell, hearing or touch is another question. 



If we attempt to analyse the method by which an animal is 

 able visually to recognize familiar objects it may well be sup- 

 posed that the impressions which it gains are either general or 

 particular. As men recognize familiar forms and faces at a 

 distance without definitely considering or perceiving the finer 

 details of feature and expression, so animals by observing gross 

 outlines and characteristic movements may draw conclusions as 

 to the nature of the forms around them. Such generalized 

 recognition of familiar objects may be considered, in part at 

 least, to have resulted from an educational process. Its acqui- 

 sition is the result of long association with the objects in ques- 

 tion. Throughout this association an appreciation of certain 

 finer distinctive differences, whether consciously or subcon- 

 sciously manifest, has been a fundamental factor in producing 

 in the animal mind a concrete appreciation of the object's iden- 

 tity in terms of the whole. 



With the human mind such processes are of common occur- 

 rence. A stranger first met with is afterward recognized by 

 the recollection of some peculiarity which has been impressed 

 upon us. With further acquaintance we forget the peculiarity 

 or it becomes subconscious, while recognition is based on the 

 broader lines of general association. The systematic entomol- 

 ogist, by laborious examination of detailed structure, differen- 

 tiates between closely related species of insects hitherto unknown 

 to him. But if he specializes upon the group, his recognition 

 of the various familiar species forming it in time becomes almost 

 intuitive, — he knows them " by sight " without consciously 

 analysing their differential markings. 



In the realm of animal intelligence it might be difficult to 

 prove directly that such generalized recognition of individuals 

 and objects was the result of a gradual mental development 

 in which discrimination by appreciation of detail gradually led 

 to a more generalized appreciation of difference. It is possible, 

 however, to subject the animal to tests which will indicate in 

 how far it is able to make fine visual discriminations, and if 



