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element always moving it in the desired direction, is inconceivable to our under- 

 standing, it rests, where it is accepted, upon hollow uncomprehended assumptions, 

 in their nature really not differing from mysticism. And what I have learned 

 from observation concerning the gradual development of an evolutionary change, 

 proceeding in a certain direction and confined to a special physiological unit, 

 is quite in accordance with the acceptance of a psychic element. 



If, in this way, especially when more than one such changes take place 

 simultaneously, a considerable change of form is brought about, there is ground, 

 as they reproduce themselves independently, for assuming, systematically, a 

 separate species, and in that case the difference in certain organs which has 

 arisen in this way, may be taken as a systematic distinguishing characteristic 

 of the new species, but it by no means follows, that merely some difference 

 in a single organ in a number of individuals of one species can constitute such 

 a distinction between them, as to justify the systematic assumption of a separate 

 species. This might be called putting the cart before the horse. It is equally 

 unnecessary for the recognition of a new species, that all the physiological 

 units or organs of the original stock should be altered. Even when this has 

 only taken place in some, the general change of form may be sufficient, and 

 it may be just those organs that remain unchanged where change in the above 

 case was taken as a systematic characteristic of a new species. For species is 

 merely a systematic form of division, not a natural one ; natural specific character- 

 istics as such, cannot exist. I am therefore unable to regard as successful the 

 endeavour of the doctrine of mutation to rehabilitate species as a natural division. 

 There is, however such a wide difference between the development of plants and 

 of animals, that it is quite possible, that observations made in the one or the 

 other field, may lead in quite different conclusions. But such a general 

 biological law as the doctrine of mutation must be true for the animal world 

 as well as that of plants, if it is to be accepted. 



The peculiarity, named variability, which is applied to elucidate the mutation 

 theory, does not exist; it is merely a fiction, invented, as it were, to personify 

 the enigmatical fact by giving it a name, and turning it into an inherent 

 property. In my opinion it should be relegated to the scientific waste-paper-basket, 

 along with the theory of mimicry, of natural and sexual selection and many 

 more such. And the so-called laws of Quetelet and his followers regulating 

 this fiction should go with them. It always astonishes me, not to see the 

 mutation theory used to defend the theory of mimicry. There the gradual 

 development of the protective qualities, according to the Darwinian theory, is 

 very improbable; they would then, in the beginning of the development, have 

 been so slight, that they could not have afforded any protection, and so there 



