"We take pieces of glass of different kinds and grind them to particular shapes and set them in a frame and make a telescope, which refracts rays of light so as to produce an 'image' of a very distant object near our eye, and that appears much larger when seen through another glass of proper shape. But we have never yet been able to make one that can bring all the rays from a single distant point exactly to another point without confusion. Yet there are many millions of apparently self-made machines in the world that do it perfectly; and when we cut up one of them and examine it we find that instead of our large lumps of glass melted together into a coarse kind of uniformity, this machine has been built up of an innumerable quantity of particles arranged in peculiar and complicated ways, some of which have objects that we can understand, though we cannot imitate them, and others that we do not. Moreover they are persistently alike in every machine of the same class, and again some of them persistently unlike those belonging to any other class of animals. For a long time the retina of the eye used to be called a membrane, or a kind of thin sheet. Then it was found to be a kind of brush of which the hairs vibrate under the vibration of the rays of light; and now these hairs are found by further magnification to be divided into so many parts lengthwise that a picture of them has to be as long as the picture of a striped or spotted animal to distinguish them; and instead of being simply set fast by one end like hairs in a brush, they pass through several frames or membranes; and of the use of all these pieces we know nothing. Such is the 'simplicity of nature' in that organ which next to a stomach is the commonest in all living creatures; and such is our ignorance of nature yet." [185] _Ibid._, c. vii. [186] Although, as bee-keepers soon discover, Mr. Darwin supposed the workmanship of bees' cells to be considerably more exact and accurate than usually is the case,--there remains quite enough of architectural merit to justify his remarks. It may even be said to increase the mystery that the insects should thus appear to strive towards an ideal, which they frequently fail to satisfy. [187] _Ranunculus ficaria._ It is remarkable that in the season of 1904 this plant has ripened fruit profusely in various districts in which such fruit had for many years been practically undiscoverable. [188] _Origin of Species_, c. xiv. [189] _Descent of Man_, Part I, c. i. [190] _Biological Lectures and Addresses_, p. 202. [191] _Charles Darwin et ses précurseurs Français_ (1870), p. 120. [192] _North British Review_, June, 1867. Professor Huxley likewise declared this criticism to be of "real and permanent value." (_Critiques and Addresses_, 252.) [193] _La vie des êtres animés_, p. 102.