can be shown that natural variation and natural selection were capable of forming the crystalline lens, it will not be denied that they were capable of forming the iris, the sclerotica, the aqueous humors, or any and all the other parts.  Suppose, then, that we have a number of animals, with eyes yet wanting the crystalline.  In this state the animals can see, but dimly and imperfectly, as a man sees after having been couched.  Some of the offspring of these animals have, by natural variation, merely a portion of the membrane which separates the aqueous from the vitreous humor a little thickened in its middle part, a little swelled out.  This refracts the light a little more than it would be refracted by a membrane in which no such swelling existed, and not only so, but, in combination with the humors, it corrects the errors of dispersion and makes the image somewhat more colorless.  All the young animals that have this swelled membrane see more distinctly than their parents or brethren.  They, therefore, have an advantage over them in the struggle for life.  They can obtain food more easily; can find their prey, and escape from their enemies with greater facility than their kindred.  This thickening and rounding of the membrane goes on from generation to generation by natural variation; natural selection all the while “picking out with unerring skill all the improvements, through countless generations,” until at length it is found that the membrane has become a perfect crystalline lens.  Now, where is the design in all this?  The membrane was not thickened and rounded to the end that the image should be more distinct and colorless; but, being thickened and rounded by the operation of natural variation, inherent in generation, natural selection of necessity produced the result that we have seen.  The same result was thus produced of necessity, in the eye, that Dollond came at, in the telescope, with design, through painful guessing, reasoning, experimenting, and forming.

Suppose our skeptic to believe in all this power of natural selection; will he now seal up his verdict for design, with the same confidence that he would before he heard of Darwin?  If not, then “the supposed proof from design is invalidated by Darwin’s theory.”

A.G.—­Waiving incidental points and looking only to the gist of the question, I remark that the argument for design as against chance, in the formation of the eye, is most convincingly stated in your argument.  Upon this and upon numerous similar arguments the whole question we are discussing turns.  So, if the skeptic was about to seal his verdict in favor of design, and a designer, when Darwin’s book appeared, why should his verdict now be changed or withheld?  All the facts about the eye, which convinced him that the organ was designed, remain just as they were.  His conviction was not produced through testimony or eyewitness, but design was irresistibly inferred from the evidence of contrivance in the eye itself.