APPENDIX 461 



Claparexle has a carrot for him and that he is to come and get it, 

 we find it exceedingly difficult to believe that he can himself make 

 up sentences about carrots and communicate them in a code to his 

 master. 1 But we may do well to consider the bearings of the whole 

 question upon the general theory of animal intelligence, which may 

 be very briefly stated. Should the whole or even a small portion 

 of Herr KralPs claim be substantiated, it would rather show the 

 immense effect of training on drawing out the potentialities of the 

 mind than alter our view as to the normal level of animal in- 

 telligence. Ordinary horses do not perform any such feats as those 

 of Muhamed and Zarif. They are incapable of communicating 

 with their masters in any such fashion. If they were, their whole 

 position in the world's economy would be different and men would 

 not be upon their backs. If anything like Herr Krall's view is 

 true, we must infer that powers like those of fixing a concept like 

 a number independent of anything seen, heard, or felt, and operat- 

 ing with it in some determinate fashion, are capable of being elicited 

 by training in a mind, which normally makes no use of any such 

 faculty. That is to say, the transition from the level of in- 

 telligence characteristic of the normal animal of the higher type to 

 that characteristic of the human being is capable of being made, 

 not by the evolution of a new type of brain but within the limits 

 of modifiability of a single brain through the stimulating powers of 

 the teacher. This would corroborate our view of the essential 

 difference between the animal and human intelligence as a differ- 

 ence due to the development of the means of inter-communication, 

 though it would attribute to this factor far more preponderating 

 influence than we have ventured to assign to it, far more even than, 

 with all Herr Krall's evidence before us, we can think is really 

 probable. 



NOTE 



The case of Rolf, the Mannheim terrier, may be more cursorily treated. 

 The truth is that, as Dr. Maday says, the story of Rolf reads almost like 

 a skit upon performances of the Elberfeld horses. Rolf learnt his arith- 

 metic while listening to the children's lessons and helps them with their 

 sums when in any difficulty. He gives orthodox answers to Jesuits and 

 keeps a private theology of a more up to date kind for his friends. Almost 

 everything he has done he has done in the presence and with the know- 

 ledge of his mistress, and the evidence for unseen experiments is slight and 

 unsatisfactory. It consists, as far as I know, first of Mackenzie's statement 

 that he showed the dog certain cards which he described. " I am sure," 

 says Mackenzie, " that absolutely no one saw the design except the dog." 

 No details are given, and it is obviously exceedingly difficult to be sure of 

 such a point when there are many people in the room. Secondly, we have 

 the observations of Doctors Gruber and Wilser. Dr. Gruber gave certain 

 cards to Rolf, which he thought he concealed from everybody else. In 



1 Archives de Psychologic, XII. p. 278. 



