EXPERIMENTS AND OBSERVATIONS 53 



name of the questioner, i. e. the person operating with 

 the horse. The four other columns give the number of 

 tests made upon each of these. The name of the person 

 who made the observation in each series is indicated at 

 the head of the column. It is unnecessary to give the 

 name of the observer of the horse, for the only difficulty 

 lay in the observation of the questioner. The numerals 

 I and II indicate two series taken at different times. 



We have omitted from this table several tests in which 

 the observer of the questioner noticed no head jerks 

 whatever, and therefore could not arrest his stop-watch, 

 although the horse responded correctly. Four tests of 

 this kind were made by Mr. von Hornbostel, two by Mr. 

 Pflingst, two by Mr. Schumann and five by Mr. Stumpf. 

 In the case of Mr. Pfungst the horse gave the unusually 

 high number of fifty taps. The attention of the observer 

 had been taxed too long and had failed him (two seconds 

 is the most favorable time). The head-jerk of Mr. von 

 Osten evidently occurred during a lapse in Mr. Pfungst's 

 attention and therefore remained unnoticed. 



