Thus, by attending to the two associations that occur,--the association (in place) of visual sensations with tangible bodies that _are not_ the eye; and the association (in place) of vision with a small tangible body that _is_ the eye--the eye regarded as the condition on which the apprehension of these sensations depends; by attending to these, we can understand how a protensive interval comes to be recognised between the organ and its objects. By means of the touch, we have associated the sensations of vision with tangible bodies in one place, and the apprehension of these sensations with a tangible body in another place. It is, therefore, impossible for the sight to dissolve these associations, and bring the sensations out of the one place where they are felt, into the other place where the _condition_ of their apprehension resides. The sight is, therefore, compelled to leave the sensations where they are, and the apprehension of them where it is; and to recognize the two as sundered from each other--the sensations as separated from the organ, which they truly are. Thus it is that we would explain the origin of the perception of distance by the eye; believing firmly that the sight would never have discerned this distance without the mediation of the touch. Rightly to understand the foregoing reasoning--indeed to advance a single step in the true philosophy of sensation--we much divest ourselves of the prejudice instilled into us by a false physiology, that what we call our organism, or, in plain words, our body, is necessarily _the seat_ of our sensations. That all our sensations come to be associated _in some way_ with this body, and that some of them even come to be associated with it _in place_, is undeniable; but so far is it from being true, that they are all essentially implicated or incorporated with it, and cannot exist at a distance from it, that we have a direct proof to the contrary in our sensations of vision; and until the physiologist can prove (what has never yet been proven) an _à priori_ necessity that our sensations must be where our bodies are, and an _à priori_ absurdity in the contrary supposition, he must excuse us for resolutely standing by the fact as we find it. This is a view which admits of much discussion, and we would gladly expatiate upon the subject, did time and space permit; but we must content ourselves with winding up the present observations with the accompanying diagram, which we think explains our view beyond the possibility of a mistake. A B_a_ _á_C