PRESIDENTIAL ADDRESS. 41 



the cells which are developed from them ; and it is impossi 

 ble to imagine any way in which the transmission of changes 

 produced by the direct action of external forces upon the somatic 

 cells, can be brought about ... To this class of phenomena 

 of course belong those acts of will which call forth the func 

 tional activity of certain groups of cells ' ' (p. 80) . ' ' Only those 

 new characters can be called ' acquired ' which owe their origin 

 to external influences, and the term ' acquired ' must be denied 

 to those which wholly depend upon the mysterious relationship 

 between the different hereditary tendencies which meet in the 

 fertilized ovum. These latter are not ' acquired ' but inherited, 

 although the ancestors did not possess them as such, but only, 

 as it were, the elements of which they are composed " (p. 252). 

 ' ' If acquired characters are brought forward in connexion 

 with the question of the transformation of species, the term 

 ' acquired ' must only be applied to those characters which do 

 not arise from within the organism, but which arise as the re 

 action of the organism under some external stimulus, most 

 commonly as the consequence of the increased or diminished 

 use of an organ or part" (p. 322). 



That such characters cannot be inherited he asserts with the 

 strongest emphasis and frequent iteration. His treatment of 

 this point often borders on the dogmatic, as a few extracts will 

 show. 



" It has never been proved " he says, " that acquired char 

 acters are transmitted, and it has never been demonstrated, 

 that, without the aid of such transmission, the evolution of the 

 organic world becomes unintelligible. The inheritance of ac 

 quired characters has never been proved, either by means of 

 direct observation or by experiment " (p. 81). ''No single 

 fact is known that really proves that acquired characters can 

 be transmitted" (p. 267). " If acquired characters cannot be 



