40 THE EVOLUTION OF LIVING BEINGS. 



ble variation has been claimed to exist,by evolutionists ? 



We all know that a great many persons, up to the 

 present day, express their belief in the inheritance of 

 so called acquired characters e. g. in the occurence of 

 changes in the characters of the individual, caused by 

 external circumstances, and in the transmittal of 

 such changes to the offspring. 



Very few among these, yet believe, in the orthodox 

 way, that external influences first change the soma 

 and through this subsequently the constitution of the 

 gametes. 



At present the adherents of theories of a transmis- 

 sion of acquired characters, usually mean a direct in- 

 fluence on the germ-plasma, causing a constitutional 

 change in the gametes, which as a matter of fact would 

 be nothing than a mutation, just as mutation is incon- 

 cievable without some kind of inheritance of acqui- 

 red characters. 



To this supposition of course applies exactly what we 

 have already said about mutations. The possibility can 

 not be denied, but proof is lacking. 



In as much as nothing happens without cause, all 

 suppositions of transmittable variability, no matter 

 whether we call the effect mutation or by some other 

 name, have to assume that, at the end, such variabiUty 

 is caused by external circumstances, have consequently 

 to admit the transmittability of acquired characters. 



Darwin clearly perceived this, as results from his let- 

 ter to Semper, written but Uttle more than half a year 

 before his death, (Life and Letters III p. 345) in which 

 he says: 



