SECTIONAL TRANSACTIONS.—J. ATT 
are enhanced. If the stimulating colour is orange, yellow or blue, two groups of 
receptors in each case, either those for red and green, or those for green and violet 
are depressed in sensitivity, while those for the remaining sensation are enhanced. 
In the regions adjoining the stimulated area, and in the retina of the unstimulated 
eye, all three receptor mechanisms are enhanced in sensitivity, though the enhance- 
ment is predominant in the sensations complementary to the stimulating colour. 
lf the stimulating colour is of very lowintensity, the effect everywhere is depression 
of sensitivity. 
These experimental results strongly support the trichromatic theory of Young. 
They also show that the physiological processes of inhibition (depression) and 
facilitation (enhancement) are invariably associated with all visual excitations. The 
supposed antagonistic colour processes assumed by Hering as the basis of his theory 
may be identified with these physiological actions, and the two chief theories of colour 
yision may thus in a measure be reconciled. 
: The mutual inductive retinal actions, in the opinion of the writer of the paper, 
_ are to be referred to reflex actions of a sensory character by which the sensitivity of 
the retinal receptors is controlled. 
On the basis of these actions we may explain the origin of simultaneous colour 
and luminosity contrast, both uniocular and binocular types. Since by the mutual 
inductive action of two retinal areas upon each other the receptor apparatus in each 
is enhanced in sensitivity but predominantly for the complementaries of the two 
stimulating colours, each colour perception will appear to be modified as if it were 
mixed with the complementary of the other. 
The sensory nervous system always tends to remain in or to resume equilibrium. 
After stimulation the recovery of equilibrium is made by a series of oscillations of 
inhibition and facilitation, or of depression and enhancement. Such actions are 
_ doubtless concerned with negative after-images. Since in each half of the neural 
_ apparatus the nervous processes may oscillate in opposite phases, as well as in the 
same phase, we have here the possible explanation of binocular rivalry and fusion 
_ of colours. 
With an excessive and permanent depression of sensitivity of the receptors for 
one or more of the fundamental colour sensations there occur the phenomena of 
“colour blindness’ ; while when the enhancing processes are excessive and permanent 
the opposite phenomena of anomalous trichromatism are exhibited by the eye. 
In the mutual inductive action of stimulated retinal areas we have the occurrence 
of reciprocal innervation, the character of which has been so elaborately investigated 
4 by Sir Charles Sherrington. Simultaneous contrast is reciprocal innervation operating 
in vision. 
The conclusions suggested by the experiments in colour vision are supported by 
similar experiments in the senses of touch, taste and audition, as well as by experiments 
on the post-contraction of muscles and the secretion of glands. 
% tof. J. Drever.—TLhe Nature of Emotion. 
Emotion, as ordinarily understood, has two aspects. On the one hand, it is a 
response of the organism; on the other hand, it is a modification of experience. 
Failure to recognise that these are two distinct aspects is a fruitful source of difficulty 
_ and controversy in modern psychology. In particular, several writers describing 
“emotion as an experience carry over this description to the consideration of the 
Telation of emotion to instinct with very unfortunate. results. These unfortunate 
results could have been avoided had they started with emotion as response, and 
worked out a systematic account of emotion as experience on this basis. So 
far the starting-point of the behaviourist would appear to be justified. When 
emotion as experience is approached in this way it is impossible to regard it as an 
elementary mode of consciousness, or even to regard it as a complex affective state 
and nothing more. 
__ The essential points which the psychology of emotion must keep in view are 
iese :-— 
1, That emotion is fundamentally a phase of the response of the organism to a 
ituation. 
__ 2. That emotion as an experience exhibits that polarity which is characteristic of 
afiective experience, ranging between the two opposite poles of joy and sorrow. 
