"If you ask me whether there exists the least evidence to prove that any form of life can be developed out of matter independently of antecedent life, my reply is that evidence considered perfectly conclusive by many has been adduced, and that were we to follow a common example, and accept testimony because it falls in with our belief, we should eagerly close with the evidence referred to. But those to whom I refer as having studied this question, believing the evidence offered in favor of 'spontaneous generation' to be vitiated by error, cannot accept it. They know full well that the chemist now prepares from inorganic matter a vast array of substances, which were some time ago regarded as the products solely of vitality. They are intimately acquainted with the structural power of matter, as evidenced in the phenomena of crystallization. They can justify scientifically their belief in its potency, under the proper conditions, to produce organisms. But, in reply to your question, they will frankly admit their inability to point to any satisfactory experimental proof that life can be developed, save from demonstrable antecedent life."[1]
Three years subsequently it fell to my lot to address the members of the Midland Institute at Birmingham, and a very few words will reveal the grounds of my reference on that occasion to the "Theory of Descent." "Ten years have elapsed," said Dr. Hooker at Norwich in 1868,[2] "since the publication of 'The Origin of Species by Natural Selection,' and it is therefore not too early now to ask what progress that bold theory has made in scientific estimation. Since the 'Origin' appeared it has passed through four English editions,[3] two American, two German, two French, several Russian, a Dutch, and an Italian. So far from Natural Selection being a thing of the past (the Athenæum had stated it to be so), it is an accepted doctrine with almost every philosophical naturalist, including, it will always be understood, a considerable proportion who are not prepared to admit that it accounts for all Mr, Darwin assigns to it." In the following year, at Innspruck, Helmholtz took up the same ground. Another decade has now passed, and he is simply blind who cannot see the enormous progress made by the theory during that time. Some of the outward and visible signs of this advance are readily indicated. The hostility and fear which so long prevented the recognition of Mr. Darwin by his own university have vanished, and this year Cambridge, amid universal acclamation, conferred on him her Doctor's degree. The Academy of Sciences in Paris, which had so long persistently closed its doors against him, has also yielded at last; while sermons, lectures, and published articles, plainly show that even the clergy have, to a great extent, become acclimatized to the Darwinian air. My reference to Mr. Darwin in the Birmingham Address was based upon the knowledge that such changes had been accomplished, and were still going on.
That the lecture of Prof. Virchow can to any practical extent dis-
