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A. D. Darbishire. 
one. He bases his theory, straight away, on the assumption that 
the character of the peas in his various generations are determined 
solely by the potentialities latent in the germ cells which give rise 
to them, and that the character of their parents and grandparents 
having nothing to do with it. Nageli, whose theory differed very 
little from Charles Darwin’s Pangenesis, could not admit the truth 
of this assumption without also admitting that the particular 
problem he had devoted his energies to solve was a fictitious 
exercise which bore no relation to actuality. Few men are able, 
or, if able, willing to appreciate the significance of work which 
involves the stultification of their own. 
The coming together of these two men, representative of 
these two diametrically opposed views, and their complete inability 
to understand one another, appears to me as one of the most 
romantic events in the history of biology. 
Before I pass on to the demonstration of what may seem the 
least credible part of my thesis, namely that the Weismannian or 
germinal theory of inheritance was not fully perceived until it 
received the support of Mendel’s discoveries, I wish to make it 
clear that I am not suggesting that this is the only revolution in 
opinion which these discoveries have brought about; and to 
explain that I have laid such stress on the part which these 
discoveries have played. in completing this revolution because 
no attention has been paid to it hitherto. 
The reason that those who have been engaged in the prose¬ 
cution of Mendelian studies have made no reference to this part 
played by Mendel’s own discoveries is not, in my opinion, that they 
would not admit that these discoveries have had this effect, but 
that they admit it so unreservedly and fully and unconsciously 
that to make any reference to it, even if it occurred to them to do 
so, would appear to them to be uttering what was merely a self- 
evident commonplace. But it should not be forgotten that these 
inferences appear with a much more vivid reality to those actually 
engaged in the investigation of natural phenomena than they do to 
those whose acquaintance with these phenomena is of necessity 
second-hand. By second-hand I do not mean that those of you 
who are not prosecuting such researches are condemned to come no 
closer to the phenomena than you can get by reading about them in 
books or hearing about them in lectures. Later on I shall show 
you specimens, illustrating many of the phenomena, which I have 
grown myself. You will see the results of the experiments. But 
