A year after the Principles of Geology appeared, there crept unnoticed into the world a treatise, by one Patrick Matthew, on Naval Timber and Arboriculture, under which unexciting title Darwin’s theory was anticipated. Of this, however, as of a still earlier anticipation, more presently. About this period Von Baer, in examining the embryos of animals, showed that creatures so unlike one another in their adult state as fishes, lizards, lions, and men, resemble one another so closely in the earlier stages of their development that no differences can be detected between them. But Von Baer was himself anticipated by Meckel, who wrote as follows in 1811: “There is no good physiologist who has not been struck, incidentally, by the observation that the original form of all organisms is one and the same, and that out of this one form, all, the lowest as well as the highest, are developed in such a manner that the latter pass through the permanent forms of the former as transitory stages” (Osborn’s From the Greeks to Darwin, p. 212). In botany Conrad Sprengel, who belongs to the eighteenth century, had shown the work effected by insects in the fertilization of plants. Following his researches, Robert Brown made clear the mode of the development of plants, and Sir William Hooker traced their habits and geographical distribution. Von Mohl discovered that material basis of both plant and animal which he named “protoplasm.” In 1844, nine years before Von Mohl told the story of the building-up of life from a seemingly structureless jelly, a book appeared which critics of the time charged with “poisoning the fountains of science, and sapping the foundations of religion.” This was the once famous Vestiges of Creation, acknowledged after his death as the work of Robert Chambers, in which the origin and movements of the solar system were explained as determined by uniform laws, themselves the expression of Divine power. Organisms, “from the simplest and oldest, up to the highest and most recent,” were the result of an “inherent impulse imparted by the Almighty both to advance them from the several grades and modify their structure as circumstances required.” Although now referred to only as “marking time” in the history of the theory of Evolution, the book created a sensation which died away only some years after its publication. Darwin remarks upon it in his Historical Sketch that although displaying “in the earlier editions little accurate knowledge and a great want of scientific knowledge, it did excellent service in this country in calling attention to the subject, in removing prejudice, and in thus preparing the ground for the reception of analogous views.”
Three years after the Vestiges, there was, although none then knew it, or knowing the fact, would have admitted it, more “sapping of the foundations” of orthodox belief, when M. Boucher de Perthes exhibited some rudely-shaped flint implements which had been found at intervals in hitherto undisturbed deposits of sand and gravel—old river beds—in the Somme valley, near Abbeville, in Picardy. For these rough stone tools and weapons, being of human workmanship, evidenced the existence of savage races of men in Europe in a dim and dateless past, and went far to refute the theories of his paradisiacal state on that memorable “23 October, 4004 B. C.,” when, according to Dr. Lightfoot’s reckoning (see p. [103]), Adam was created. While the pickaxe, in disturbing flint knives and spearheads, that had lain for countless ages, was disturbing much besides, English and German philosophers were formulating the imposing theory which, under the name of the Conservation of Energy, makes clear the indestructibility of both matter and motion. Then, to complete the work of preparation effected by the discoveries now briefly outlined, there appeared, in a now defunct newspaper, the Leader, in its issue of 20th of March, 1852, an article by Herbert Spencer on the Development Hypothesis, in which the following striking passage occurs: “Those who cavalierly reject the Theory of Evolution, as not adequately supported by facts, seem quite to forget that their own theory is supported by no facts at all. Like the majority of men who are born to a given belief, they demand the most rigorous proof of any adverse belief, but assume that their own needs none. Here we find, scattered over the globe, vegetable and animal organisms numbering, of the one kind (according to Humboldt) some 320,000 species, and of the other, some 2,000,000 species (see Carpenter); and if to these we add the numbers of animal and vegetable species that have become extinct, we may safely estimate the number of species that have existed, and are existing, on the earth, at not less than ten millions. Well, which is the most rational theory about these ten millions of species? Is it most likely that there have been ten millions of special creations? or is it most likely that by continual modifications, due to change of circumstances, ten millions of varieties have been produced, as varieties are being produced still?... Even could the supporters of the Development Hypothesis merely show that the origination of species by the process of modification is conceivable, they would be in a better position than their opponents. But they can do much more than this. They can show that the process of modification has effected, and is effecting, decided changes in all organisms subject to modifying influences.... They can show that in successive generations these changes continue, until ultimately the new conditions become the natural ones. They can show that in cultivated plants, domesticated animals, and in the several races of men, such alterations have taken place. They can show that the degrees of difference so produced are often, as in dogs, greater than those on which distinctions of species are in other cases founded. They can show, too, that the changes daily taking place in ourselves—the facility that attends long practice, and the loss of aptitude that begins when practice ceases—the strengthening of passions habitually gratified, and the weakening of those habitually curbed—the development of every faculty, bodily, moral, or intellectual, according to the use made of it—are all explicable on this same principle. And thus they can show that throughout all organic nature there is at work a modifying influence of the kind they assign as the cause of these specific differences; an influence which, though slow in its action, does, in time, if the circumstances demand it, produce marked changes—an influence which, to all appearance, would produce in the millions of years, and under the great varieties of condition which geological records imply, any amount of change.”
This quotation shows, as perhaps no other reference might show, how, by the middle of the present century, science was trembling on the verge of discovery of that “modifying influence” of which Mr. Spencer speaks. That discovery made clear how all that had preceded it not only contributed thereto, but gained a significance and value which, apart from it, could not have been secured. When the relation of the several parts to the whole became manifest, each fell into its place like the pieces of a child’s puzzle map.
Leading Men of Science.
A. D. 800 TO A. D. 1800.