ADAPTATION 211 



pads and that they could transmit these novelties to descendants 

 raised in normal conditions. Till evidence of this kind is pub- 

 lished by at least two independent observers investigating similar 

 material, I find it easier to believe that mistakes of observation or 

 of interpretation have been made than that any genuine trans- 

 mission of acquired characters has been witnessed. 



Meanwhile there is no denying that the origin of adaptational 

 features is a very grave difficulty. With the lapse of time since 

 evolutionary conceptions have become a universal subject of study 

 that difficulty has, so far as I see, been in nowise diminished. 

 But I find nothing in the evidence recently put forward which 

 justifies departure from the agnostic position which most of us 

 have felt obliged to assume. 30 



APPENDIX TO CHAPTER IX. 



Professor G. Klebs, as is well known to students of evolution- 

 ary phenomena, has for several years been engaged in investi- 

 gations 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: 



8. Juli 1912 



Ihre liebenswurdige Anfrage will ich sehr gern beantworten, 

 obwohl ich sie nicht so beantworten kann wie ich erwiinschte. 

 Ihr Skepticismus in der Frage der Uebertragung erworbener 

 Charactere auf die Nachkommen ist nur zu berechtigt. Meine 

 Versuche mit Veronica sind nicht beweisend, da es mir bisher 

 nicht gelungen ist eine einigermasse konstante Varietat mit 

 verlaubten Inflorescenze zu erzeugen. In Bezug auf mein 

 Semper vivum bin ich allerdings noch heute der Meinung dass 



30 As to the experiments of Klebs relating to the transmission of acquired char- 

 acters, see Appendix. 



