376 TITCHENER AND PYLE— ON THE AFTER-IMAGES [July 23. 



often wrong than right.^ Their influence upon the after-image ap- 

 peared only in the case of the subjective observer N. Thus, R seen 

 on W was judged by N to be " red or blue " ; and the after-image, 

 also on W, was a large irregular disc of yellow. R seen on Bk was 

 judged to be " bluish " ; and the after-image, on gray, was green- 

 blue with a vague yellow rim. B seen on W was judged " blue or 

 red " ; and the after-image, on gray, was red above and blue below, 

 with a yellow patch between. It is noteworthy that here, as in Exp, 

 II,, after-images of the " supposed " or " imagined " color invariably 

 differed in form and size from those of the true color. The ob- 

 server did not realise the significance of this difference, though in 

 time he would doubtless have learned to use it as a secondary 

 criterion, 



II, Indirect Vision. 

 We have already mentioned the experiments made by T in 1906 

 with the view of testing the conclusions of Miss Fernald's first 

 paper. The observations were rigorously confined to the Bk-W 

 zone, and their outcome was definitely negative. In the meantime, 

 however, the arousal of a colored after-image by a subliminally 

 colored stimulus had been maintained for both the B-Y and the 

 R-G zones. Unsystematic observations made in the Cornell Labora- 

 tory failed to confirm this result. It seemed worth while, however, 

 to obtain further testimony; and Professor J. W. Baird, of the 

 University of Illinois, very kindly consented to investigate the 

 subject.^ 



* One of the observers remarked "that the experiments showed — what he 

 had never fully understood before — how it is that a case of partial color- 

 blindness may remain undetected both by the color-blind person himself and 

 by the normal persons in his surroundings. In principle, the remark was 

 correct enough ; but in practice the observer would have had to revise and 

 extend his criteria very considerably. 



" All the observations in indirect vision mentioned in this paper were 

 carried out with light-adaptation. Peripheral after-images in dark-adapta- 

 tion are practically non-existent. In op. cit., 56 f ., Baird writes : " After- 

 images — in the ordinary sense of the term — were almost invariably absent 

 from our experiments. They were reported in less than one per cent, of 

 our exposures ; and when they did occur, they were aroused by the stimula- 

 tion of paracentral, never of peripheral, regions of the retina." And in a 

 personal letter he adds : " There is an interesting difference of function in 



