being. It remained so for a very long period; but it is now a
considerable number of years since a distinguished foreign chemist
contrived to fabricate Urea, a substance of a very complex character,
which forms one of the waste products of animal structures. And of
late years a number of other compounds, such as Butyric Acid, and
others, have been added to the list. I need not tell you that
chemistry is an enormous distance from the goal I indicate; all I wish
to point out to you is, that it is by no means safe to say that that
goal may not be reached one day. It may be that it is impossible for
us to produce the conditions requisite to the origination of life; but
we must speak modestly about the matter, and recollect that Science has
put her foot upon the bottom round of the ladder. Truly he would be a
bold man who would venture to predict where she will be fifty years
hence.

There is another inquiry which bears indirectly upon this question, and
upon which I must say a few words. You are all of you aware of the
phenomena of what is called spontaneous generation. Our forefathers,
down to the seventeenth century, or thereabouts, all imagined, in
perfectly good faith, that certain vegetable and animal forms gave
birth, in the process of their decomposition, to insect life. Thus, if
you put a piece of meat in the sun, and allowed it to putrefy, they
conceived that the grubs which soon began to appear were the result of
the action of a power of spontaneous generation which the meat
contained. And they could give you receipts for making various animal
and vegetable preparations which would produce particular kinds of
animals. A very distinguished Italian naturalist, named Redi, took up
the question, at a time when everybody believed in it; among others our
own great Harvey, the discoverer of the circulation of the blood. You
will constantly find his name quoted, however, as an opponent of the