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 
recognition. In DARWIN'S time many 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. 1 
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 Intraccllular Pangenesis I have 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. 2 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 the 
1 See Different Kinds of Variability in Darwin and Modern Sci- 
ence, pp. 66-74, I 99- 
Intraccllular Pangenesis, translated into English by Prof. C. 
STUART GAGER, 1910. 
