VIII.] SUPPOSED TRANSMISSION OF MUTILATIONS. 435 



mutilations, the great German philosopher, Kant, has distinctly 

 denied that transmission can take place ^ ; and in more recent 

 times Wilhelm His has expressed the same opinion^. 



But if the transmission of acquired characters is truly im- 

 possible 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 V 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 excluded. I therefore en- 

 deavoured to show that these difficulties are not in reality 

 insurmountable, and that it is quite possible to explain 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 unnecessary 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 

 assumption of the transmission of acquired characters in 



^ It is true that he based his opinions upon entirely erroneous theories 

 as to the constancy of species. Compare Brock, ' Einige altere 

 Autoren iiber die Vererbung erworbener Eigenschaften ' in ' Biolog. 

 Centralblatt,' Bd. VIII, p. 491 (1888 : see also Hugo Spitzer, ' Bcitrage 

 zur Descendenz-theorie und zur Methodologie der Naturwissenschaft,' 

 Leipzig, 1886, pp. 515 et seq. 



2 W. His, ' Unsere KOrperform,' Leipzig, 1875. 



^ See Essay II in the present volume. 



F f 2 



