for so situated, we seem to touch bodies directly, and to have no impression from them through a medium.
But tangible differ from visible and sonorous impressions, in that the latter are perceived by the medium acting in some way upon us, while the former are perceived, not by, but together with, the medium, like a man who is struck through his shield; —for it is not the shield which, having been struck, strikes him, but the shield and he are simultaneously struck together. To use a general expression, the flesh and the tongue seem to be in the same relation to the touch which air and water are to sight, hearing, and smell; —are disposed towards that organ, that is, as each of those elements is to each of those senses. When the sentient organ itself is touched, no sensation can there or then be produced, any more than a white object can be seen when placed immediately over the surface of the eye; and thus it is evident that the part perceptive of tangible impressions must be within. Thus, it should be with the touch, as with the other senses; and if objects, when placed upon an organ, are not perceived, but, when placed upon the flesh, they are perceived, we must conclude that the flesh is only the medium for tangible impressions.
The distinctions of the body, as body, are tangible distinctions, and by these I mean distinctions such as distinguish the elements, as hot, cold, dry and moist, upon which we have heretofore spoken in our treatise
