Butler founded no school, and wished to found none. He desired that what was true in his work should prevail, and he looked forward calmly to the time when the recognition of that truth and of his share in advancing it should give him in the lives of others that immortality for which alone he craved.
Lamarckian views have never lacked defenders here and in America. Of the English, Herbert Spencer, who however, was averse to the vitalistic attitude, Vines and Henslow among botanists, Cunningham among zoologists, have always resisted Weismannism; but, I think, none of these was distinctly influenced by Hering and Butler. In America the majority of the great school of palæontologists have been strong Lamarckians, notably Cope, who has pointed out, moreover, that the transformations of energy in living beings are peculiar to them.
We have already adverted to Haeckel’s acceptance and development of Hering’s ideas in his “Perigenese der Plastidule.” Oscar Hertwig has been a consistent Lamarckian, like Yves Delage of the Sorbonne, and these occupy pre-eminent positions not only as observers, but as discriminating theorists and historians of the recent progress of biology. We may also cite as a Lamarckian—of a sort—Felix Le Dantec, the leader of the chemico-physical school of the present day.
But we must seek elsewhere for special attention to the points which Butler regarded as the essentials of “Life and Habit.” In 1893 Henry P. Orr, Professor of Biology in the University of Louisiana, published a little book entitled “A Theory of Heredity.” Herein he insists on the nervous control of the whole body, and on the transmission to the reproductive cells of such stimuli, received by the body, as will guide them on their path until they shall have acquired adequate experience of their own in the new body they have formed. I have found the name of neither Butler nor Hering, but the treatment is essentially on their lines, and is both clear and interesting.
In 1896 I wrote an essay on “The Fundamental Principles of Heredity,” primarily directed to the man in the street. This, after being held over for more than a year by one leading review, was “declined with regret,” and again after some weeks met the same fate from another editor. It appeared in the pages of “Natural Science” for October, 1897, and in the “Biologisches Centralblatt” for the same year. I reproduce its closing paragraph:—
“This theory [Hering-Butler’s] has, indeed, a tentative character, and lacks symmetrical completeness, but is the more welcome as not aiming at the impossible. A whole series of phenomena in organic beings are correlated under the term of memory, conscious and unconscious, patent and latent. … Of the order of unconscious memory, latent till the arrival of the appropriate stimulus, is all the co-operative growth and work of the organism, including its development from the reproductive cells. Concerning the modus operandi we know nothing: the phenomena may be due, as Hering suggests, to molecular vibrations, which must be at least as distinct from ordinary physical disturbances as Röntgen’s rays are from ordinary light; or it may be correlated, as we ourselves are inclined to think, with complex chemical changes in an intricate but orderly succession. For the present, at least, the problem of heredity can only be elucidated by the light of mental, and not material processes.”
It will be seen that I express doubts as to the validity of Hering’s invocation of molecular vibrations as the mechanism of memory, and suggest as an alternative rhythmic chemical changes. This view has recently been put forth in detail by J. J. Cunningham in his essay on the “Hormone [0f] Theory of Heredity,” in the Archiv für Entwicklungsmechanik (1909), but I have failed to note any direct effect of my essay on the trend of biological thought.
Among post-Darwinian controversies the one that has latterly assumed the greatest prominence is that of the relative importance of small variations in the way of more or less “fluctuations,” and of “discontinuous variations,” or “mutations,” as De Vries has called them. Darwin, in the first four editions of the “Origin of Species,” attached more importance to the latter than in subsequent editions; he was swayed in his attitude, as is well known, by an article of the physicist, Fleeming Jenkin, which appeared in the North British Review. The mathematics of this article were unimpeachable, but they were founded on the assumption that exceptional variations would only occur in single individuals, which is, indeed, often the case among those domesticated races on which Darwin especially studied the phenomena of variation. Darwin was no mathematician or physicist, and we are told in his biography that he regarded every tool-shop rule or optician’s thermometer as an instrument of precision: so he appears to have regarded Fleeming Jenkin’s demonstration as a mathematical deduction which he was bound to accept without criticism.
Mr. William Bateson, late Professor of Biology in the University of Cambridge, as early as 1894 laid great stress on the importance of discontinuous variations, collecting and collating the known facts in his “Materials for the Study of Variations”; but this important work, now become rare and valuable, at the time excited so little interest as to be ‘remaindered’ within a very few years after publication.
In 1901 Hugo De Vries, Professor of Botany in the University of Amsterdam, published “Die Mutationstheorie,” wherein he showed that mutations or discontinuous variations in various directions may appear simultaneously in many individuals, and in various directions. In the gardener’s phrase, the species may take to sporting in various directions at the same time, and each sport may be represented by numerous specimens.
De Vries shows the probability that species go on for long periods showing only fluctuations, and then suddenly take to sporting in the way described, short periods of mutation alternating with long intervals of relative constancy. It is to mutations that De Vries and his school, as well as Luther Burbank, the great former of new fruit- and flower-plants, look for those variations which form the material of Natural Selection. In “God the Known and God the Unknown,” which appeared in the Examiner (May, June, and July), 1879, but though then revised was only published posthumously in 1909, Butler anticipates this distinction:—
“Under these circumstances organism must act in one or other of these two ways: it must either change slowly and continuously with the surroundings, paying cash for everything, meeting the smallest change with a corresponding modification, so far as is found convenient, or it must put off change as long as possible, and then make larger and more sweeping changes.
“Both these courses are the same in principle, the difference being one of scale, and the one being a miniature of the other, as a ripple is an Atlantic wave in little; both have their advantages and disadvantages, so that most organisms will take the one course for one set of things and the other for another. They will deal promptly with things which they can get at easily, and which lie more upon the surface; those, however, which are more troublesome to reach, and lie deeper, will