Popular Science Monthly/Volume 52/December 1897/An Early American Evolutionist
|AN EARLY AMERICAN EVOLUTIONIST.|
PROFESSOR OF PATHOLOGY, UNIVERSITY OF GEORGIA.
AS a general rule, the influence of the theory of evolution as a potent factor in the biological sciences is considered to date from the publication of the Origin of Species in November, 1859. It is true that the theory did not originate with Mr. Darwin. It may be traced in more or less definite shape through the whole history of philosophy, and in our own century Lamarck formulated a doctrine of development as fully as could be done with the data at hand in his day. The Origin of Species was fortunate in finding an expositor so simple and clear in style, so accurate and full in scientific knowledge as Mr. Huxley. Equally at home before the British Association for the Advancement of Science or a Workingmen's Lyceum, he brought to his subject the same conviction of right, the same strong, vigorous English, and the same rigorous logic that had enabled him at the age of thirty-five to face the Bishop of Oxford, and Owen, the foremost anatomist of his time, and vanquish each in turn before the greatest assembly of scientific students that gathers in Great Britain. With such a disciple and apostle it is not wonderful that the name and fame of Darwin should have been indissolubly connected with evolution, although his chief work in relation to it was an effort to determine the precise means by which variation was perpetuated and increased.
How the religious world rose in arms at the suggestion of such a hypothesis is well known. From the College of the Propaganda to the most extreme of the dissenting churches, all shades of religious opinion united to denounce the theory and those who upheld it, and the echoes of the conflict have not died away even now. Under these circumstances it is with a curious interest that we examine a work that was issued a few months before the Origin of Species saw the light, and, after seeing how fully it foreshadowed the later work, compare the approbation with which religious leaders hailed it with the denunciation heaped on the other by the same writers.
The title-page reads: The Testimony of Modern Science to the Unity of Mankind, being a Summary of the Conclusions announced by the Highest Authorities in the Several Departments of Physiology, Zoölogy, and Comparative Philology in Favor of the Specific Unity and Common Origin of all the Varieties of Man. By J. L. Cabell, M. D., Professor of Comparative Anatomy and Physiology in the University of Virginia. With an Introductory Notice by James W. Alexander, D. D. New York: Robert Carter & Brothers, No. 530 Broadway, 1859.
Such is the wording of this title that it received the indorsement of no less an authority than Dr. Alexander, and the "introductory
notice" is full of the highest praise of the work and of its leading idea.
Americans may well be proud of this book, as it states many of the biological laws now recognized, and, strange to say, cites many of the very instances used later by Huxley and Darwin to support them. Among these we find, on page 22, that by changing food and environment, "we may modify to an extent sometimes quite considerable the outward structural character of many plants and low animal organisms; and these newly acquired characters may then be perpetuated by hereditary transmission, under the influence of the law of assimilation between parent and offspring, even though the causes which originally determined the variation from the primitive type have ceased to operate. A similar effect is produced in those cases in which a given variation appears accidentally in a single individual and is then transmitted to his offspring. . . . In other words, a permanent variety is likely to arise." In the Origin of species, Chapter I, in speaking of variations, Darwin says: "We are driven to conclude that this great variability is due to our domestic productions having been raised under conditions of life not so uniform as, and somewhat different from, those to which the parent species had been exposed under Nature." The same idea is here expressed in somewhat different words, and Darwin's notion as to the transmission of such peculiarities by heredity is too familiar to be repeated.
As an illustration of the law thus laid down, Cabell cites the well-known story of the origin of the Ancon or Otter sheep from a spontaneous variation occurring in the flock of Seth Wright in Massachusetts; and it may be remembered that Huxley uses the same incident in the same relation, but without reference to its previous use by Prichard and Cabell. As further evidence, he brings forward the changes arising in the horses and cattle that were brought to this continent as domesticated animals, but escaped into the forests and plains, and shows that without admixture—for these animals are not indigenous—varieties arose differing from the parent stock so markedly as to constitute new species. On the other hand, he shows that the hog, an exotic animal brought here under domestication, reverted to the primitive stock. So striking is this that it will repay copying in full (page 31):
"The hog is known not to be indigenous to this country, but was introduced into St. Domingo at the first discovery of that island in 1493, and successively to all the places where the Spaniards formed settlements. These animals multiplied with great rapidity and soon invested the forests in large herds. At length, under the influence of their wild state, they have resumed the characters of the original stock—that is, their appearance very closely resembles that of the European wild boar, from which the domesticated breeds have sprung. Their ears have become erect, their heads are larger, and their foreheads vaulted at the upper part; their color has lost the variety found in the domestic breeds, the wild hogs of the American forests being uniformly black. The hog which inhabits the high mountains of Paramos bears a striking resemblance to the wild boar of France. His skin is covered with thick fur, often somewhat crisp, beneath which is found in some individuals a species of wool. Thus the restoration of the original characters of the wild boar, in a race known to have sprung from domesticated swine brought over to America by the Spaniards, removes all reason for doubt, if any had existed, as to the identity of the wild and domesticated stocks in Europe, and we may safely proceed to compare the physical characters of these races as varieties which have arisen in one species." (Unity, etc., pages 32, 33.)
As will be remembered, the leading instance of reversion cited in the Origin of Species is the tendency of fancy breeds of pigeons to return to the "blue rock," from which fact Mr. Darwin concludes that to be the original stock. As the hog is a more highly organized animal than the pigeon, this flexibility of species in it is more striking than in the oviparous pigeon.
As suggested above, it is probable that much of the interest excited by the Origin of Species was due to the brilliant exposition of Mr. Huxley; but, aside from that, unquestionably the chief reason that so many without the ranks of professional biologists discussed its reasoning so eagerly and earnestly was the bearing it had on the genesis of man. Mr. Huxley's lectures touched almost every branch of modern science—zoölogy, bacteriology, geology, sociology—all were equally familiar to this, perhaps the greatest public lecturer of our race, but to none of them did the laity give the rapt attention that was and still is given to evolution. The bearing of spontaneous variation among the lower orders of living organisms on the human race was clearly seen by Dr. Cabell, and the object of his work was to offset the arguments of those who claimed a plurality of genera among men by showing that lower organisms develop varieties without the intervention of any supernatural creative power. As a necessary inference from this, and, indeed, that it should have any bearing at all on the problem of humanity, he must have held that there was no radical difference between man and other animals.
The similarity between the arguments used by Cabell and those to be used a few months later by Darwin is striking, and equally remarkable is it that both should have foreseen objections to the theory, and that these objections are essentially identical. The difficulty of defining species as distinct from variety impressed them both; the alleged sterility of hybrids, an objection answered by both by showing it not to be invariable; the lack of intermediate forms, attributed by Darwin to the imperfection of the geological record and by Cabell to imperfect geographical knowledge, and several similar instances, can not fail to impress an attentive reader.
This neglected volume is a wonderful monument of painstaking labor and erudition, and although overshadowed by the more extensive works that appeared a few months later from the great English writers, it is one in which American biologists may take pride. Most remarkable, however, is the fact that it was greeted with delight and exultation by the leaders of religious thought, whereas the work of Mr. Darwin, hardly more than an expansion of Cabell's Unity, in which the same arguments and many of the same instances appeared, was denounced with all the vigor of ecclesiastical vituperation. The reason for this difference in reception is not easily seen.
- Philosophic Zoologique. Par J. Lamarck. Paris, 1809.