48 THE HORSE OF MR. VON OSTEN 



Now after Hans had ceased tapping, the questioner would 

 raise his head and trunk to their normal position. This 

 second, far coarser movement was not the signal for the 

 back-step, but always followed it. But whenever this 

 second movement was omitted, Hans, who had already 

 brought back his foot to the original position and had 

 thereby put it out of commission, as it were, would give 

 one more tap with his left foot. 



If it was true that these movements of the questioner 

 guided the horse in his tapping, then the following must 

 be shown : First, that the same movements were observed 

 in Mr. von Osten in every case of successful response; 

 secondly, that they recurred in the same order or with 

 only slight individual changes in the case of all who were 

 able to obtain successful responses from the horse, and 

 that they were absent or occurred at the wrong time in 

 all cases of unsuccessful response. Furthermore, it was 

 observed that it was possible to bring about unsuccessful 

 reactions on the part of the horse as soon as the move- 

 ments were voluntarily suppressed, and conversely, that 

 by voluntarily giving the necessary signs the horse might 

 be made to respond at pleasure ; so that anyone who pos- 

 sessed the knowledge of the proper signs could thereby 

 gain control over the process of response on the part of 

 the horse. These requirements have all been fulfilled, as 

 we shall see in the following pages. 



With regard to the regular recurrence of the move- 

 ments noticed in the case of Mr. von Osten, I was, after 

 some practice, able to note carefully their peculiar char- 

 acteristics. This was rather difficult, not only on account 

 of their extreme minuteness, but also because that very 

 vivacious gentleman made sundry accompanying move- 



