Correspondence on Biology, etc. 



The most remarkable steps yet made in advance are, I 

 think, the theory of Weismann of the continuity of the 

 germ plasm, and its corollary that acquired modifications 

 are never inherited! and Patrick Geddes's explanation of 

 the laws of growth in plants on the theory of the antagon- 

 ism of vegetative and reproductive growth. . . . — Yours 

 very sincerely, Alfred R. Wallace. 



To Prof. Meldola 

 Frith Hill, Godalming. March 20, 1888. 



My dear Meldola, — I have been working away at my 

 hybridity chapters,^ and am almost disposed to cry 

 ''Eureka'." for I have got light on the problem. When 

 almost in despair of making it clear that Natural Selec- 

 tion could act one way or the other, I luckily routed out 

 an old paper that I wrote twenty years ago, giving a 

 demonstration of the action of Natural Selection. It did 

 not convince Darwin then, but it has convinced me now, 

 and I think it can be proved that in some cases (and those 

 I think most probable) Natural Selection will accumulate 

 variations in infertility between incipient species. Many 

 other causes of infertility co-operate, and I really think I 

 have overcome the fundamental difficulties of the question 

 and made it a good deal clearer than Darwin left it. . . . 

 I think also it completely smashes up Romanes. — Yours 

 faithfully, Alfred R. Wallace. 



The next letter relates to a question which Prof. Meldola 

 raised as to whether, in view of the extreme importance of 

 '' divergence " (in the Darwinian sense) for the separation 

 and maintenance of specific types, it might not be possible 

 that sterility, when of advantage as a check to crossing, 

 had in itself, as a physiological character, been brought 



* For the yrork on " Darwinism." 

 41 



