_Lunatic, Lover, and Poet._—A still better analogy of the manner in which one feeling may be modified by another is furnished by the optical phenomenon of after-images. If we gaze very steadily for half a minute at a green wafer and then at a sheet of white paper, we see on it a _purple_ image of the wafer; purple being the complementary colour of green, _i.e._ the colour which, if mixed with green, produces white. The reason of this phenomenon is that, after looking at the green wafer, the nervous fibres in the eye which perceive that colour have become so fatigued that the fainter green waves in the white paper fail to make any perceptible impression on them; so that purple alone prevails for the moment. So to the infatuated swain who has been tortured by the green-eyed monster, Jealousy, the moment of remission, which would else be one of neutral indifference, assumes the hue of rosy hope and positive delight. Hours which to sober mortals would seem perfect blanks are thus to him full of intense feeling, simply because they are rebounds from a state of extreme tension in the opposite direction. He might be likened to a schoolboy whose sleigh is carried across the frozen river by its downward impetus and even ascends the hill on the other side some distance before it stops. Hence, like the madman and the man of genius, the amorous swain is always either down in a fit of melancholy, or in an exalted ecstasy of joy, rapidly alternating and weirdly intermingled— “The lunatic, the lover, and the poet, Are of imagination all compact.”