THE PERPETUATION OF LIVING BEINGS, HEREDITARY TRANSMISSION AND
VARIATION

by Thomas Henry Huxley




The inquiry which we undertook, at our last meeting, into the state of
our knowledge of the causes of the phenomena of organic nature,--of the
past and of the present,--resolved itself into two subsidiary
inquiries: the first was, whether we know anything, either historically
or experimentally, of the mode of origin of living beings; the second
subsidiary inquiry was, whether, granting the origin, we know anything
about the perpetuation and modifications of the forms of organic
beings. The reply which I had to give to the first question was
altogether negative, and the chief result of my last lecture was, that,
neither historically nor experimentally, do we at present know anything
whatsoever about the origin of living forms. We saw that, historically,
we are not likely to know anything about it, although we may perhaps
learn something experimentally; but that at present we are an enormous
distance from the goal I indicated.

I now, then, take up the next question, What do we know of the
reproduction, the perpetuation, and the modifications of the forms of
living beings, supposing that we have put the question as to their
origination on one side, and have assumed that at present the causes of
their origination are beyond us, and that we know nothing about them?
Upon this question the state of our knowledge is extremely different;
it is exceedingly large, and, if not complete, our experience is