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to feel no difficulty in the matter — lineal descent from some early 
fish or reptile — “ some ancient prototype furnished with a floating 
apparatus or swimming-bladder” — Mr Darwin regards as the noblest 
claim of ancestry. {t When I view all beings,” he says, “ not as 
special creations, but as the lineal descendants of some few beings 
who lived long before the first bed of the Silurian system was 
deposited, they seem to me to be ennobled.” I am afraid that the 
honour of this parentage, as regards our own species, will not be 
universally appreciated. The question, however, is not whether it 
be “ennobling” or the reverse, but whether it can be proved or 
rendered in any degree probable. Yet, in judging of the sufficiency 
of evidence, it is well to recollect the full weight of the conclusion 
which that evidence must be strong enough to bear ; nor, in this 
point of view, do I think it wholly unphilosophical to bear in mind 
the innate beliefs and instincts of mankind. 
It is not, however, my duty or my desire, in this place and on 
this occasion, to enter more deeply into the specific argument on 
the “ origin of species;” I would rather indicate wherein the discus- 
sion, and the argument which has raised that discussion, has most 
directly tended to the advance of science. In this respect, it is not 
too much to say that the whole book is full of the most curious and 
original observation, and exhibits in an eminent degree that power 
and habit of arranging and co-ordinating physical phenomena which 
is essential to the attainment of great results, and which it has been 
the special use of such theories in the history of science to evoke 
and to direct. In particular, I think no one can read Darwin's 
chapter on the “struggle for existence,” or the two chapters on 
“ geographical distribution,” without feeling that new and important 
light has been cast on subjects which are as interesting as they are 
difficult and obscure. 
I hope I need not assure the Members of this Society how highly 
I value the honour which places me in this chair. To be chosen 
President of a Society of which the two former Presidents were 
Sir W. Scott and Sir T. Brisbane is indeed an honour of which any 
Scotchman may well be proud. But whilst these names are of 
themselves sufficient to indicate how great that honour is, they are 
not less sufficient to remind me that your choice of President is 
determined on different occasions by considerations of very various 
