ity?

The materialistic attitude is not distinctively biological, but is
common to practically all fields of thought. It dates back to the
Greek atomists, and the triumph of mechanical science in the 19th
century has induced many to accept materialism as the only possible
scientific method. In biology it is more akin to the formal than to
the functional attitude.

In the course of this book I have not hidden my own sympathy with the
functional attitude. It appears to me probable that more insight will
be gained into the real nature of life and organisation by
concentrating on the active response of the animal, as manifested both
in behaviour and in morphogenesis, particularly in the post-embryonic
stages, than by giving attention exclusively to the historical aspect
of structure, as is the custom of "pure morphology." I believe we
shall only make progress in this direction if we frankly adopt the
simple everyday conception of living things--which many of us have had
drilled out of us--that they are active, purposeful agents, not mere
complicated aggregations of protein and other substances. Such an
attitude is probably quite as sound philosophically as the opposing
one, but I have not in this place attempted any justification of it. I
have touched very lightly upon the controversy between vitalism and
materialism which has been revived with the early years of the present
century. It hardly lends itself as yet to historical treatment, and I
could hardly hope to maintain with regard to it that objective
attitude which should characterise the historian.

The main result I hope to have achieved with this book is the
demonstration, tentative and incomplete as it is, of the essential
continuity of animal morphology from the days of Aristotle down to our
own time. It is unfortunately true that modern biology, perhaps in
consequence of the great advances it has made in certain directions,
has to a considerable extent lost its historical consciousness, and if
this book helps in any degree to counteract this tendency so far as
animal morphology is concerned, it will have served its purpose.

I owe a debt of gratitude to my friends Dr James F. Gemmill and Prof.
J. Arthur Thomson for much kindly encouragement and helpful criticism.
The credit for the illustrations is due to my wife, Mrs Jehanne A.
Russell. One is from Nature; the others are drawn from the original
figures.

E.S.R.

CHELSEA, 1916.

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