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^trinanimrte thing S PP Objection to the phrase as liable to lead 



ranges himself among the uncritical. 21 



Bonn's inattention to my statements as to the cause of reaction 

 of course leads him to suppose that whenever I speak of trial 

 and error I mean that there is no experimental cause for the 

 reactions: hence if he can show that there is experimental cause, 

 this does away with the concept of trial and error! He there- 

 fore takes up a number of cases of reaction described by me 

 (pp. 172-175, 187-195, etc.), shows, as I had done before, that 

 they are due to changes in environmental conditions, and con- 

 cludes that my exposition is wrong; that the application of the 

 idea of trial and error is a mistake. His idea of trial and error 

 is that it involves chance, in the sense of being undetermined. 



By the analysis that I have made above, 1 have been led to reject 



In whose mind was the illusion ? My own statement has been : 



Again, Bohn says : "Indeed, many of the sinuosities of the path 

 followed by the lower animals can find an explanation in the 

 combination of the tropisms and the phenomena of sensibility 

 to differences" (p. 279), and in all seriousness he copies some 

 of my figures and instructs me that the reactions shown are due 

 to changes in the environmental conditions, just as I had shown 

 before him. Some of the facts here are almost incredible ; they 

 throw a strange light on the author's accuracy and intelligent 

 grasp. Thus, in the case of one of the figures copied from me 

 (on p. 188), from which he draws on p. 191 the conclusion that 

 I have "not taken into account the sensibility to differences," 



21 It is a remarkable fact that in an earlier review of my book (Bui. 

 Inst. Gen. Psychologique, 1906 (?), p. 282), Bohn understood correctly 



understands. It would be most interesting to know the internal history of 

 the change by which Bohn has been brought from a position of intelligent 



