The older writers, though they had some vague
idea that it must be so, did not study Variation and Heredity. Darwin
did, and so begat not a theory, but a science.

The extent to which this is true, the scientific world is only
beginning to realise. So little was the fact appreciated in Darwin's
own time that the success of his writings was followed by an almost
total cessation of work in that special field. Of the causes which led
to these remarkable consequences I have spoken elsewhere. They
proceeded from circumstances peculiar to the time; but whatever the
causes there is no doubt that this statement of the result is
historically exact, and those who make it their business to collect
facts elucidating the physiology of Heredity and Variation are well
aware that they will find little to reward their quest in the leading
scientific Journals of the Darwinian epoch.

In those thirty years the original stock of evidence current and in
circulation even underwent a process of attrition. As in the story of
the Eastern sage who first wrote the collected learning of the
universe for his sons in a thousand volumes and by successive
compression and burning reduced them to one and from this by further
burning distilled the single ejaculation of the Faith "There is no god
but God and Mohammed is the Prophet of God," which was all his maturer
wisdom deemed essential:--so in the books of that period do we find
the _corpus_ of genetic knowledge dwindle to a few prerogative
instances and these at last to the brief formula of an unquestioned
creed.

And yet in all else that concerns biological science this period was,
in very truth, our Golden Age, when the natural history of the earth
was explored as never before; morphology and embryology were
exhaustively ransacked; the physiology of plants and animals began to
rival chemistry and physics in precision of method and in the rapidity
of its advances; and the foundations of pathology were laid.

In contrast with this immense activity elsewhere the neglect which
befel the special physiology of Descent, or Genetics as we now call
it, is astonishing. This may of course be interpreted as meaning that
the favoured studies seemed to promise a quicker return for effort,
but it would be more true to say that those who chose these other
pursuits did so without making any such comparison; for the idea that
the physiology of Heredity and Variation was a coherent science,
offering possibilitie