136 MARINE BIOLOGICAL LABORATORY. 



of Weismann's views are, that the nucleus of the germ 

 cell is the sole bearer of the hereditary tendencies ; that 

 the expulsion of each of the two polar bodies of the 

 ovum has a distinct meaning, the first expelling the 

 ovogenetic nucleoplasm, the second reducing the ances- 

 tral germ plasm by one half, and thus rendering the 

 nucleus ready for the accession of the germ plasm of the 

 spermatozoan which has previously been correspondingly 

 reduced. While these subsidiary hypotheses, if correct, 

 would strengthen Weismann's position, I do not see that 

 his theory is dependent upon them. 



Now look at his main propositions, first, as against 

 Brooks, there is no fundamental distinction between 

 male and female germ cells ; second, as against Darwin 

 and Lamarck, the early separation and isolation of the 

 germ plasm from the somatoplasm, renders it highly im- 

 probable that acquired characters can be inherited, for 

 the changes in the body can exert no definite influences 

 upon the germ cells. It is at once evident that this 

 theory explains admirably the repetition-phenomena, and 

 is strong upon the embryological side. Before criticising 

 it from the non-repetitive or evolution standpoint let us 

 examine the views of Galton. 



It is certainly very remarkable that there are so many 

 points of agreement between Weismann and Galton, 

 when we consider their diverse fields of research. Galton 

 was the pioneer, and the fact that Weismann indepen- 

 dently reached similar conclusions from entirely different 

 data, affords a strong presumption in favor of their com- 

 mon grounds of opinion — that the physical vehicle of 

 heredity is continuous and feebly or not at all influenced 

 by changes in the individual which conveys it. Some 



