INTRODUCTION 9 



tests naturally were the first steps toward a positive in- 

 vestigation. The results were such that Mr. Schillings 

 was led to replace his hypothesis of independent concep- 

 tual thinking by one of some kind of suggestion. In 

 this he was strengthened somewhat by having noted 

 the fact that in his questions which he put to the horse, 

 he might proceed as far as to ask the impossible. He 

 has always been ready to oflfer himself in the tests which 

 have been undertaken since then. 



On October 13, 1904, together with the two gentlemen 

 mentioned in the beginning of my report, I began my 

 more detailed investigation, and finished on November 

 29. We worked for several hours on the average of 

 four times each week. I take this opportunity of giving 

 expression of the recognition which is due to the two 

 gentlemen. They were ready to go to the courtyard in 

 all kinds of weather, at times they went without me, and 

 they always patiently discussed the order and method 

 of the experiments and the results. Dr. von Hornbostel 

 had the important task of keeping the records, and Mr. 

 Pfungst undertook the conduct of the experiments. It 

 was he, who, soon after the blinder-tests disclosed the 

 necessary presence of visual signs, discovered the nature 

 of these signs. Without him we might have shown the 

 horse to be dependent upon visual stimuli in general, 

 but we never would have been able to gain that mass of 

 detail, which makes the case valuable for human psychol- 

 ogy. But I am tempted to praise not merely his patience 

 and skill, but also his courage. For we must not believe 

 that Mr. von Osten's horse was a " perfectly gentle " 

 animal. If he stood untied and happened to be excited 

 by some sudden occurrence, he would make that court- 

 yard an unsafe place, and both Mr. Schillings and Mr. 



