  What is particularly luminous in all the theories that express the most recent anti-Darwinian tendency is that they tend to bring into prominence the mysterious powers of living organisms, by means of which, instead of passively waiting for natural selection and the continual accumulation of unceasing variations, they are able spontaneously and of themselves to bring forth what is necessary for self-maintenance, often what is new and different, of course not unlimitedly, but with considerable freedom and often with a surprising range of possibilities. It is, perhaps, partly the fault of the one-sidedness of strict Darwinism that this consideration has been so slowly brought into prominence and subjected to investigation and experiment. It is bound up with the capacity that all forms of life have of reacting spontaneously to “stimuli” and, to a certain extent, of helping themselves if the conditions of existence be unfavourable. They are able, for instance, to produce protective adaptations [pg 178] An effectively modified and adapted type of Alpine flora has not been evolved by a laborious process of selection lasting for many thousand years; the organism may quickly and immediately produce the new characters by its own reaction. Crustaceans gradually transferred from a salt-water to a fresh-water habitat, or conversely, produce in a few generations the type of a new “species” with correlated variations (Schmankewitsch). Birds weaned by careful experiment from a diet of seeds to one of flesh, or conversely, produce changes of effective correlation and adaptation in the characters of their alimentary system. Plants that have been deprived of their normal organs for absorbing water and prevented from growing new ones produce entirely new and effective “hydatodes.”50 [pg 179]It is instructive to notice that Darwinism seems likely to be robbed of its stock illustration, namely, “protective coloration.” By its own internal power of reaction, and sometimes within one generation, and even in the lifetime of an individual, an organism may assume the colour of the substratum beneath it (soles, grasshoppers), of its surroundings (Eimer's tree frogs), the colour and spottiness of the granite rock on which it hangs, the colour of the leaves and twigs among which it lives (Poulton's butterfly pupÆ), and even that of the brightly coloured sheets of paper amidst which it is kept imprisoned. Certain spiders assume a white, pink, or greenish “protective coloration” corresponding to the tinted blossom of the plants which they frequent, and so on.51 Eimer alleged that direct psychical factors co-operated in bringing about these changes. In any case, all this carries us far beyond the domain of mere naturalistic factors into the mystery of life itself. Even what is called the “influence of the external world,” and the “active acquirement of new characters,” have their basis and the reason of their possibility in this domain. And the whole domain is saturated through and through with “teleology.” A recognition of the impressive secret of the organism led Gustav Wolff to become a very pronounced critic of Darwinism, especially in the form of Weismannism. [pg 180] “That a spirit of earnestness would once more enter into biological investigation, which would no longer attempt to find in nature just what it wanted to find, but would be ready to follow truth at all costs, and to approach the riddle of life with an open mind.” His “BeitrÄge zur Kritik der Darwinischen Lehre,” which appeared first as papers in the “Biologisches Centralblatt,” did not see the light in book form until 1898. The doctrine of selection was regarded as so unassailable that no publisher would take the risk of the book. Its appearance is a sure indication of the general modification of opinions that had taken place in the interval. The first and second essays are merely critical objections to the theory of selection, very similar to those frequently urged before, but more precisely stated.52 The third is intended to show that there is in the forms of life themselves, as a faculty of adaptation peculiar to them, a primary purposiveness, which is unquestionably active throughout the lifetime and development of every individual, but which is also the deepest cause of “phylogenesis,” or the formation [pg 181] More comprehensively, but from a precisely similar standpoint, Driesch has followed up the discussion of this problem.53 He is, of all modern investigators, perhaps the one who has most persistently and thoroughly [pg 182] |
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