Vv 
HEREDITY AND VARIATION IN MODERN LIGHTS 
By W. Bateson, M.A., F.R.S. 
Professor of Biology in the University of Cambridge. 
Darwin's work has the property of greatness in that it may be 
admired from more aspects than one. For some the perception of 
the principle of Natural Selection stands out as his most wonderful 
achievement to which all the rest is subordinate. Others, among 
whom I would range myself, look up to him rather as the first who 
plainly distinguished, collected, and comprehensively studied that 
new class of evidence from which hereafter a true understanding of 
the process of Evolution may be developed. We each prefer our 
own standpoint of admiration ; but I think that it will be in their 
wider aspect that his labours will most command the veneration of 
posterity. 
A treatise written to advance knowledge may be read in two 
moods. The reader may keep his mind passive, willing merely to 
receive the impress of the writer’s thought; or he may read with his 
attention strained and alert, asking at every instant how the new know- 
ledge can be used in a further advance, watching continually for 
fresh footholds by which to climb higher still. Of Shelley it has been 
said that he was a poet for poets: so Darwin was a naturalist for 
naturalists. It is when his writings are used in the critical and more 
exacting spirit with which we test the outfit for our own enterprise 
that we learn their full value and strength. Whether we glance back 
and compare his performance with the efforts of his predecessors, or 
look forward along the course which modern research is disclosing, we 
shall honour most in him not the rounded merit of finite accomplish- 
ment, but the creative power by which he inaugurated a line of 
discovery endless in variety and extension. Let us attempt thus to 
see his work in true perspective between the past from which it grew, 
and the present which is its consequence. Darwin attacked the 
problem of Evolution by reference to facts of three classes: Varia- 
