i82 THE HORSE OF MR. VON OSTEN 



of the discussion again.** And this for two reasons. 

 The dog never took his gaze from his master and ap- 

 peared to be entirely dependent upon him in his reac- 

 tions. Hans, on the other hand, seemed to give evidence 

 of a high degree of independence and never appeared to 

 look at the questioner. But we know now that, though 

 he was never dependent upon the will of his master, he, 

 ^too, abjectly hung upon the man's involuntary movements 

 and never for a moment lost him from view. But since 

 the horse is able to observe with one eye alone, and 

 needed to direct only it and not the entire head toward 

 the questioner, in order to focus comfortably, one could 

 not conclude as to his line of vision from the direction of 

 the head. Since, furthermore, in the horse the pupil is 

 hardly distinguishable from the darkly pigmented iris 

 and since the white sclerotic is hidden by the eyelids, 

 except when the eye is turned very much, it is difficult to 

 determine what direction the eye is taking. I once pur- 

 posely stepped backward to the horse's flank, so that he 

 had to turn his eye far back and thus the outer border 

 of the iris and the white sclerotic coat became visible 

 and all doubt concerning the line of vision was removed. 

 This doubt could never, arise in the case of the dog, the 

 median plane of whose head is always directed toward 

 the object fixated, and Zborzill is justified in saying, as 

 he does, in his discussion of training of the kind men- 

 tioned on page 177, " But any careful observer can im- 

 mediately guess the mariner in which such a dog has 

 been trained." °* If Hans had chanced to possess so- 

 called " glass-eyes " — in which the dark pigment is 

 wholly or partly lacking, so that the black pupil is clearly 

 defined against the lighter background, — then no doubt 

 could ever have arisen concerning the direction of the 



