172 Inheritance of Acquired Characters 



sively local equilibrium or the repetition in the 

 descendants of the phenomena by which the parent 

 organism reacted is hindered. This experiment must 

 rather be directed toward modifications of the functional 

 adaptation, wihch have a very extensive action and whose 

 repetition in the descendants is not hindered by anything. 



In order that these experiments on the changes 

 dependent upon functional adaptation may constitute an 

 incontestable proof for or against the inheritance of 

 acquired characters, which latter are to be understood 

 in Weismann's sense as only somatic and not general 

 peculiarities of the entire organism, they must be 

 planned in such a way as to make it certain that the 

 change effected by the transforming influence has affected 

 only the soma directly, and for still greater certainty it 

 ought to act upon only a definite part of the soma 

 and not upon the entire soma to the same extent. They 

 must also be undertaken on pluricellular organisms in 

 which the somatic germ cells are clearly differentiated, 

 and there ought to be employed as transforming influ- 

 ences only such as certainly exert no direct influence upon 

 the reproductive cells. 137 



All plants in which the difference between somatic 

 and germ cells is not a thorough going and definite one 

 will therefore be less suitable for these researches than 

 animals, and particularly higher animals, and all such 

 investigations both in animals and in plants which em- 

 ploy physical or chemical transforming agents exerting 

 a general action on the entire organism, on the somatic 

 cells as well as on the germ cells, as for example tem- 



187 Compare J. De Meyer: L'heredite des caracteres acquis est- 

 elle experimentalement verifiable? Archives de Biologic. Tome XXI, 

 No. Ill and IV. Paris, Masson 1905, P. 625, 634 639. 



