PAXGENESIS. 179 



account of the hypothesis, viz. the view that the real 

 facts which imperatively demand some material to 

 pass from the body-cells to the germ-cells in order 

 to account for their hereditary transmission are the 

 effects of use and disuse, or the influence of surround- 

 ings in fact, all those characters which are now 

 called " acquired." And it is impossible to escape 

 the conclusion that, if acquired characters are 

 transmissible by heredity, an hypothesis which 

 is substantially that of pangenesis will have to 

 be accepted. Darwin did not doubt this trans- 

 mission, and he framed pangenesis mainly to 

 account for it. 



Considerable doubt has of recent years been thrown 

 upon the transmission of acquired characters, and if 

 hereafter this doubt be justified, it will be possible to 

 substitute for pangenesis a hypothesis like the " con- 

 tinuity of the germ-plasm" brought forward by 

 Professor Weismann. A few words indicating the 

 contrast between the two hypotheses may not be out 

 of place. 



In Professor Weismann's hypothesis the germ- 

 plasm contained in the nucleus of the germ-cell pos- 

 sesses, if placed under right conditions, the power of 

 developing into an organism. It is not, however, en- 

 tirely used up during development, and the part which 

 remains grows and is stored in the germ-cells of the 

 offspring, and ultimately develops into the succeeding 

 generation. Hence parent and offspring resemble 

 each other because they are formed from the same 



