THE SUPPOSED TRANSMISSION OF MUTILATIONS. 423 



the great German philosopher, Kant, has distinctly denied that 

 transmission can take place l ; and in more recent times Wilhelm 

 His has expressed the same opinion 2 . 



But if the transmission of acquired characters is truly impossible 

 our theory of evolution must undergo material changes. We 

 must completely abandon the Lamarckian principle, while the 

 principle of Darwin and Wallace, viz. natural selection, will gain an 

 immensely increased importance. 



When I first expressed this opinion in my essay ' On Heredity 3 ,' 

 I was well aware of the consequences of such an idea. I knew well 

 that apparently insurmountable obstacles would be raised against 

 any explanation of evolution, from which the principle of the direct 

 transformation of the species by external influences had been ex- 

 cluded. I therefore endeavoured to show that these difficulties are 

 not in reality insurmountable, and that it is quite possible to ex- 

 plain certain phenomena, such as the degeneration of useless parts, 

 without the aid of the Lamarckian principle. Furthermore it can 

 be shown that a not inconsiderable number of instincts, viz. all 

 those which are exercised only once in 'a lifetime, cannot possibly 

 have arisen by transmitted practice. This fact renders it unneces- 

 sary to make use of the Lamarckian principle for the explanation 

 of other kinds of instinct. I do not mean to deny the existence 

 of phenomena for which such an explanation has not yet been 

 found, or at least has not been brought forward ; but on the other 

 hand it appears to me that it has never been proved that we 

 cannot dispense with the Lamarckian principle in the explanation 

 of these phenomena. At any rate, I do not know of any facts 

 which could induce us to abandon from the first any hope of finding 

 an explanation without the aid of this hypothesis. 



If we are able to prove that we may dispense with the assump- 

 tion of the transmission of acquired characters in explaining such 

 phenomena, of course it by no means follows that we must dispense 

 with it ; or, in other words, it does not follow that the transmission 



1 It is true that he based his opinions upon entirely erroneous theories as to the 

 constancy of species. Compare Brock, ' Einige iiltere Autoren iiber die Vererbung 

 erworbener Eigenschaften ' in 'Biolog. Centralblatt,' Bd. VIII, p. 491 (1888): see 

 also Hugo Spitzer, 'Beitrage zur Descendenz-theorie und zur Methodologie der 

 Naturwissenschaft,' Leipzig, 1886, pp. 515 et seq. 



3 W. His, 'Unsere Korperform,' Leipzig, 1875. 



3 See Essay II in the present volume. 



