370 STUDIES IN SPECIAL SENSE PHYSIOLOGY 

 Pupillo- Motor Values. 



Brightness Values. 



(Readings obtained when the same subject adjusted the intensities of 

 the lights until they seemed to be equally bright.) 



In view of the long series of experiments bearing upon the 

 Purkinje effect, the increase in brightness of the short waved 

 spectral lights at the expense of the long waved vibrations, the 

 reader is probably satisfied that this effect if not solely peripheral 

 is at least mainly so. I do not wish to disregard those who ha ye 

 obtained central adaptation, but even they admit the increase 

 to be far less marked than the peripheral alterations ; we may, 

 without undue scepticism, entertain some doubts as to whether the 

 positive results might not have been due to some slight eccentricity 

 of fixation. However that may be, we are beyond question 



