156 An Examination of Weismannism. 



lengthy parts of the old one. for the purpose of 

 showing how the most recent theory had been arrived 

 at. Hence, seeing that my previous criticism was 

 far from having been rendered obsolete by the large 

 changes which had taken place in Weismann's system 

 of theories, I concluded that it was best to retain 

 what I had written, and add the present paragraphs 

 for the purpose of dealing exclusively with the 

 changes in question. 



In now proceeding to do this. I think it is needless 

 to occupy space by giving the reasons which have 

 caused Weismann thus to abandon his doctrine of the 

 universal stability of germ-plasm since the first origin 

 of sexual propagation, and to substitute the precisely 

 opposite doctrine of its universal instability. It is 

 enough to say that these reasons all arise by way 

 of logical necessity from the further working out in 

 The Germ-plasm of his theory of heredity — or, more 

 correctly, from the additions which he has there made 

 to his previous views on the mechanism of heredity. 

 Thus he has reversed his former doctrine touching 

 the absolute stability of germ-plasm, not so much 

 on account of any of the general considerations or 

 particular facts which I have adduced against it in 

 Chapter IV, as because it would not tally with the 

 recent additions which he has made to other parts 

 of his system. Any one who cares to follow this 

 matter will find the reasons in question fully and 

 lucidly stated in Chapter XIV of The Germ-plasm 1 . 



1 It is almost needless to say that no fault is to be found with 

 Weismann for having thus reversed his opinion touching one of his 

 fundamental postulates. Consistency is no merit in a man of science ; 

 and least of all where matters of such high speculation are concerned. 

 I think, however, that it is open to question whether an author of any 



