2. "In consequence of this power, whilst in a state of comparative blindness, children who have their cataracts removed are enabled immediately on the acquisition of sight to form some judgment of the distance, and even of the outline, of those strongly defined objects with the color of which they were previously acquainted." Both these conclusions are simply matter of fact. It only needs explanation how the distance and outlines of objects can be known after the operation _in consequence of_ the ability described in the first proposition. That distance is actually estimated at once in consequence of this power, is clear; not so with the outlines. How can round and angular be distinguished, when only colors and gross differences of intensity and saturation are perceived? Ware gives no solution of the difficulty, but thinks that, because the colors appeared more intense, the previously imperfect ideas concerning distances might be improved and extended, so that they would even give a knowledge of the boundary-lines and of the form of those things with the color of which the patients were previously acquainted. But this improvement of the ideas concerning distance can not lead directly to discrimination of the limits of objects, and is itself hypothetical, inasmuch as we might expect, _immediately_ after the operation, on account of the enormous difference in the luminous intensity, an uncertainty in the judgment. But such uncertainty appeared only in a slight degree in both the cases, a thing possible only because there had already been sufficient experiences with the eye. But these experiences, as is frequently stated, were absolutely lacking in regard to the limits and the form of objects. Here another thing comes in to help. Evidently, an eye that distinguishes only colors sees these colors always only as limited; even if it saw only a single color that occupied the whole field of vision, the field would still be a limited one. But the colored field may be small or large, and this difference may be noticed before the operation. If the object--one of vivid coloring--is long and narrow, the patient, even before the operation, will see it otherwise than if it is, with the same coloring, short and broad. And suppose he merely observes that not the whole field of vision is colored. If the whole field is colored, there is, of course, an entire lack of angles; on the other hand, if the whole field of vision is not filled by the colored object, then it is--however faintly--divided, and the lines of division, i. e., the indistinct boundary-lines of the objects whose color is perceived, may be either like the natural limits of the entire field of vision, i. e., "round," or unlike them, i. e., "angular." If, now, the obstacle is suddenly removed, the patient (even if he did not before the operation distinguish angular and round by the eye) must yet perceive which of