life are unicellulars; the primitive forms also were. With them began the colossal genealogical tree that branches out through the millions of years of the earth’s history. If anything on the earth has arisen by spontaneous generation out of dead matter, at the commencement of all life, it must have been a cell, or a still simpler particle of living plasm more or less resembling one. It is true that the point is put in the form of a question; but the veil has been torn away. Given _one_ cell, the whole genealogical tree grows on, in virtue of Darwin’s laws, until it reaches its highest point in man. The conclusion of the speech greets Darwin as the Newton of the organic world, a phrase that has often been repeated since. * * * * * Let us turn over a few pages more in the faded record of the sitting. Fourteen years later he would speak again at a scientific congress, and speak on Darwinism. He would then put it forward no longer as a hope but a fulfilment, of which he showed one glittering facet. And no other than Rudolf Virchow, his former teacher, would oppose him and deliver his famous speech on the freedom of science in the modern State and its abuse by Darwin’s followers. This was at Munich in 1877. The least of his hearers would remember that Virchow had spoken, like Haeckel, at Stettin fourteen years previously. But we must understand the thirty-sixth speech if we are to understand the thirty-seventh. It was the second sitting, on September 22nd. Virchow spoke on “the alleged materialism of modern science.” The subject was not provoked by Haeckel, but by Schleiden, the botanist, the parent of the cell-theory. The controversy over materialism had raged furiously for many years. We need only mention Büchner (whose _Force and Matter_ appeared in 1855) and Carl Vogt. There was an element of necessity, but a good deal of superficiality in the controversy, as it was then conducted. Friedrich Albert Lange has given us a masterly history of it. At this moment it was particularly instructive to point out the difference between general philosophical skirmishing with words and a really able piece of work that, though it had a technical look, suddenly added a new province to philosophy on which every doubting Thomas could lay his hands. However, Schleiden had not advanced. Curiously enough, he, the first discoverer of the cell, attacked Virchow’s theory of man as a cell-state as a typical materialist extravagance. He had published a heated essay, and Virchow defended himself. He gave such a remarkable and characteristic expression of his inmost feelings that it is worth while disinterring it. It is a very rare thing for a thoughtful man to give a natural-philosophical speech that begins with crystalline clearness of logic and then makes a most curious _salto mortale_ at the critical point. [Illustration: ERNST HAECKEL, 1880. _Reproduced from the Natürliche Schöpfungsgeschichte._ ]