30 P8TOH0LOOT. 



results were mutual, and tliat sounds which were on the 

 limits of audibility became audible when lights of various 

 colors were exhibited to the eye. Smell, taste, touch, sense 

 of temperature, etc., were all found to fluctuate when lights 

 were seen and sounds were heard. Individuals varied much 

 in the degree and kind of effect produced, but almost every 

 one experimented on seems to have been in some way 

 aflected. The phenomena remind one somewhat of the 



* dynamogenic ' effects of sensations upon the strength of 

 muscular contraction observed by M. Fere, and later to be 

 described. The most familiar examples of them seem to be 

 the increase of pain by noise or light, and the increase of 

 nausea by all concomitant sensations. Persons suffering in 

 any way instinctively seek stillness and darkness. 



Probably every one will agree that the best way of for- 

 mulating all such facts is physiological : it must be that the 

 cerebral process of the first sensation is reinforced or other- 

 wise altered by the other current which comes in. No one, 

 surely, will prefer a psychological explanation here. Well, 

 it seems to me that all cases of mental reaction to a plural- 

 ity of stimuli must be like these cases, and that the phy- 

 siological formulation is everywhere the simplest and the 

 best. When simultaneous red and green light make us see 

 yellow, when three notes of the scale make us hear a chord, 

 it is not because the sensations of red and of green and of 

 each of the three notes enter the mind as such, and there 



* combine ' or ' are combined by its relating activity ' into 

 the yellow and the chord, it is because the larger sum of 

 light- waves and of air-waves arouses new cortical processes, 

 to which the yellow and the chord directly correspond. 

 Even when the sensible qualities of things enter into the 

 objects of our highest thinking, it is surely the same. Their 

 several sensations do not continue to exist there tucked 

 away. They are replaced by the higher thought which, 

 although a different psychic unit from them, knows the 

 same sensible qualities which they know. 



The principles laid down in Chapter VI seem then to 

 be corroborated in this new connection. You cannot build 

 up one thought or one sensation out of many; and only direct 



