VII. 



ON 



THE SUPPOSED BOTANICAL PROOFS OF 

 THE TRANSMISSION OF ACOUIRED 



CHARACTERS. 



In a lecture on heredity, delivered in 1883 \ I first brought 

 forward the opinion that acquired characters cannot be trans- 

 mitted ; and I then stated that there are no proofs of such 

 transmission, that its occurrence is theoretically improbable, 

 and that we must attempt to explain the transformation of 

 species without its aid. Since that time many biologists have 

 expressed their opinions upon the subject, some of them 

 agreeing with me, while others have taken the opposite side. 

 It is unnecessary to allude to those who have attacked my 

 opinions without first understanding the real point in dispute, 

 which turns upon the true meaning of the phrase 'acquired 

 character.' I think it is now generally admitted that a very 

 important problem is involved in this question, the solution 

 of which will contribute in a decisive manner towards the 

 formation of ideas as to the causes which have produced the 

 transformation of species. For if acquired characters cannot 

 be transmitted, the Lamarckian theory completely collapses, 

 and we must entirely abandon the principle by which alone 

 Lamarck sought to explain the transformation of species, — a 

 principle of which the application has been greatly restricted 

 by Darwin in the discovery of natural selection, but which was 

 still to a large extent retained by him. Even the apparentl}' 

 powerful factors in transformation — the use and disuse of 

 organs, the results of practice or neglect — cannot now be 

 regarded as possessing any direct transforming influence upon 

 a species. And the same is true of all the other direct in- 



* See the second Essay ' On Heredity.' 



