"It is often said that the conditions that presided over the production
of the first living organisms are still present and must always have
been present. But if (and what a big if!) we could imagine that in such
a small puddle of tepid water containing all sorts of ammonium and
phosphate salts, subject to certain conditions of light, electricity,
etc., a protein substance would form, ready to undergo other, more
complex changes. In our day, such a substance would immediately be
devoured or absorbed, which would not have been the case at the time
when no living creature had yet been formed."
This quote from Darwin (private crrespondence, 1871) is cited in THE
CHEMISTRY OF LIFE by Martin Olomucki (McGraw-Hill, 1993) p 9.
Hope it helps.