Page:Physiological Researches upon Life and Death.djvu/37

Rh more vigorously affected and transmits to the brain a stronger image. It is to avoid this confusion, that one eye is shut when the action of the other is artificially augmented by a convex glass: the glass destroys the harmony of the two organs, we use but the one, that there may be no discordance. What a glass produces artificially, the strabismus affords a natural example of. We squint, says Buffon, because we turn the weakest eye from the object upon which the strongest is fixed, and thereby avoid the confusion which would otherwise arise from the perception of two unequal images.

I know that many other causes concur to produce this affection, but the reality of this cannot be disputed. I know also that each eye has the power of acting separately in different animals; that two different images are transmitted at the same time by the two eyes of certain species; but this does not hinder that the two impressions which they transmit to the brain be analagous, when these organs unite their action upon die same object. A uniform judgment becomes the result: now how could this judgment be formed with correctness if the same body presented itself at the same time with a lively and a weak colouring, according as it should be painted upon the one or the other retina?

What we have said of the eye may be applied also to the ear. If in the two sensations which compose the hearing, the one is received by an organ stronger and better developed, it will leave a clearer and more distinct impression; the brain differently affected by each, would be the seat of an imperfect perception only. It is this which constitutes a false ear. Why is one man painfully affected by a dissonance which is not perceived by another? It is because in the former, the two perceptions of the same sound