THE PRESENT POSITION OF THE THEORY OF ORGANIC EVOLUTION. 121 



the acquiring of knowledge, if we are determined to be satisfied 

 with nothing for which Nature does not afford evidence. 



On the question of acquired characters, may I read what 

 Professor Bateson says in his book, Problems of Genetics, published 

 in 1912 1 



" Professor G. Klebs, as is well known to students of evolutionary 

 phenomena, has for several years been engaged in investigations 

 relating to the inheritance of acquired characters. In his many 

 publications on the subject the issue has always been represented as 

 more or less uncertain. 



"Desiring to know how the matter now stands according to 

 Professor Klebs' present judgment, I wrote to him asking him to 

 favour me with a brief general statement. This he most kindly sent 

 in a letter dated 8th July, 1912. 



" As such a statement will be read with the greatest interest by 

 all who are watching the progress of these studies, I obtained 

 permission to publish it as follows : — 



(the letter was in German — the translation I have supplied) 



'8th July, 1912. 



1 1 will willingly answer your amiable question although I cannot 

 answer it as I desired. Your scepticism in the question of the trans- 

 ference of acquired characteristics to descendants is only too justified. 



' My experiments with Veronica are not conclusive (beweisend), 

 since I have not hitherto succeeded in producing a variety to a 

 certain extent constant, with inflorescence having foliage. In regard 

 to my Sempervivum, I am of course to-day still of the opinion that 

 the strong artificial alteration of the bloom has had an influence on 

 individual descendants. I have hitherto published nothing on this 

 subject, the majority of the abnormal double flowers were unfortunately 

 sterile. I obtained some seedlings from a less altered example, but 

 they have not yet flowered. In this case it may only be a question 

 of the subsequent effects (Nachwirkung) in the first generation, 

 comparable to those cases in which seeds of trees from the high Alps 

 show certain subsequent effects in the plain. But up to the present there 

 is no certain case known in which the character artificially brought about has 

 been transmitted through several generations under the usual " normal " 

 conditions. 



' On the other hand, these negative results are not decisive. For 



