18 INITIATIVE IN EVOLUTION 



Weismann's work on the germ-plasm in pursuance of a theory 

 of heredity is pronounced by Romanes to have remained up to 

 1893 substantially unaltered, though largely added to in matters of 

 detail, and at the present time as far as I gather from a study of 

 the more recent literature this theory holds the field or at least a 

 commanding position in it. 1 Originally he held that the germ- 

 plasm possessed perpetual continuity since the first origin of life, 

 and absolute stability since the first origin of sexual propagation, 

 but he has shown himself willing to surrender the first postulate, 

 and has himself altered the second. As it stands now it must be 

 admitted that the continuity of the germ-plasm is an interrupted 

 continuity with the appearance of every inherited change ; the 

 continuity is theoretical, not actual, and the stability of the germ- 

 plasm is not absolute but of a high degree. We can thus see in the 

 story of this original theory of heredity the lighthouse value of the 

 pharos of Ptolemy II. 



It is far otherwise with Weismann's theory of evolution. 

 Romanes shows that with the removal of its essential postulate 

 the absolute stability of germ -plasm, Weismann's theory of evolu- 

 tion falls to the ground. He has indeed surrendered much in his 

 later building, his second temple of Solomon, and prominent among 

 these was the claim that the only causes of individual variation 



1 Romanes, Examination of Weismannism, p. 115. 



" It is doubtful if anything better as to Weismann's theory of heredity can 

 be said to-day than Romanes said in 1893, and inasmuch as these two latter 

 or distinctive postulates are not needed for Weismann's theory of heredity, 

 while they are both essential to his theory of evolution, I cannot but regret 

 that he should have thus crippled the former by burdening it with the latter. 

 Hence my object throughout has been to display, as sharply as possible, the 

 contrast that is presented between the brass (" iron " preferably) and the clay 

 in the colossal figure which Weismann has constructed. Hence also my 

 emphatic dissent from his theory of evolution does not prevent me from 

 sincerely appreciating the great value which attaches to his theory of heredity. 

 And although I have noi- hesitated to say that this theory is, in my opinion, 

 incomplete ; that it presents not a few manifest inconsistencies, and even 

 logical contradictions ; that the facts on which it is founded have always 

 been facts of general knowledge ; that in all its main features it was present 

 to the mind of Darwin, and distinctly formulated by Galton ; that in so far 

 as it has been constituted the basis of a more general theory of organic evolution 

 it has proved a failure ; such considerations in no way diminish my cordial 

 recognition of the services which its distinguished author has rendered to 

 science by his speculations upon these topics. For not only has he been 

 successful in drawing renewed and much more general attention to the 

 important questions touching the transmissibility of acquired characters, the 

 causes of variation, and so on ; but even those parts of his system which have 

 proved untenable are not without such valuo as temporary scaffoldings present 

 in relation to permanent buildings. Therefore, if I have appeared to play 

 the role of a hostile critic, this has been only an expression of my desire to 

 separate what seems to me the grain of good science from the chaff of bad 

 speculation." 





