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species apart from Natural Selection and all the limita
tions which that theory presupposes.
The appearance of an individual with a considerable
divergence from the normal type, and the power of that
individual to impress its special likeness on its descend
ants, is another source of necessary transmutation. The
principle of correlation of growth, which is necessary for
the conversion of one co-ordinated structure into another,
has also to be taken account of. And finally, we have to
remember that it is quite certain that some of the factors
must sometimes work together, and the result of their
common action will be proportionately great.
It may well be that there are other factors of Organic
Evolution yet to be discovered. It may be that living
matter may have a tendency to develope in a certain way
in consequence of its particular composition. I mean
that it may be possible that there should be a connection
between certain organic combinations and the forms
which they produce, just as there is a tendency in certain
chemical compounds to crystallise in a special manner.
But whether this last contention can be sustained or not,
it suffices for my present purpose to affirm that the argu
ments for Organic Evolution in their abstract form are
independent of any arguments in favour of a particular
law through which this evolution has taken place ; that so
far as they are cogent (and their cogency is generally
admitted), we are compelled to believe that there must be
efficient agencies to bring about this result ; and that we are
already in possession of many facts which tend to confirm
that belief. When investigation shall have been carried still
further, I believe that new facts will be discovered tending
in the same direction. The process may be a long one.
Favourite theories, supported by the majority of scientific
investigators, will not be relinquished at once. But the