632 Vehicles of the Hereditary Characters. 



attempted in various cases to distinguish between these 

 two types of variation. 



Even now this contrast does not yet find so clear an 

 expression in the available facts as to insure its immediate 

 recoonition. In Darwin's time manv more obstacles 

 stood in its way, and it is probable that its real signifi- 

 cation did not become manifest to him until after he 

 attempted to deal with the phenomena of heredity in a 

 theoretical way.-^ 



As is well known, this attempt was made in his pre- 

 liminary hypothesis of "pangenesis" ; it is also known 

 that he attempted to adapt his idea to other theories, 

 prevalent at the time, by a series of subsidiary hypoth- 

 eses which have now become superfluous; and that by 

 doing so he did more harm than good to his theory. 

 For, in combating these secondary hypotheses, most of 

 his critics have overlooked the real value and significance 

 of the main thesis. 



In my book on Intracellular Pangenesis I liave at- 

 tempted to show how the importance of Darwin's hy- 

 pothesis can only be really appreciated if it is freed of 

 these superfluous adjuncts.^ In this essay I have also 

 endeavored to prove that the germ of the theory reap- 

 pears, in a more or less similar form, in the hypotheses 

 of his successors ; and that in these too, it is usually 

 confused by useless or even erroneous suppositions. My 

 object was to extract this essence and to bring it into as 

 close relation with the available knowledge as was pos- 

 sible without the aid of too many auxiliary hypotheses. 



It is not now my intention to give a review of tlie 



\Sce Different Kinds of J'^oriahilify in Darwin and Modern Sci- 

 ence, pp. 66-/4, 1909- 



^ IntraceUiilar Pangenesis, translated into English by Prof. C. 

 Stuart Gager, 1910. 



