4. THE KEAL KESULTS AND THE UNSOLVED PROBLEMS OF 



TRANSFORMISM 



WHAT has been explained to a certain extent by the two 

 great theories now current is only this. Systematic diver- 

 sities consisting in mere differences as to intensity or 

 number may perhaps owe their origin to ordinary variation. 

 They may at least, if we are entitled to assume that heredity 

 in some cases is able to hand on such variations without 

 reversion, which, it must be again remarked, is by no means 

 proved by the facts at present. Natural selection may share 

 in this process by eliminating all those individuals that do 

 not show the character which happens to be useful. That 

 is the Darwinian part of an explanation of transformism 

 which may be conceded as an hypothesis. On the other 

 side, congenital histological adaptedness may be regarded 

 hypothetically as due to an inheritance of adaptive 

 characters which had been acquired by the organism's 

 activity, exerted during a great number of generations. 

 That is the Lamarckian part in the theory of descent. 



But nothing more is contributed to this theory either 

 by the doctrine of Darwin or by that of Lamarck. So it 

 follows that almost everything has still to be done; for no 

 hypothesis at present accounts for the foundation of all 

 systematics, viz., for the differences in organisation, in all 



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