Schleiden had first shown in 1838 that the body of any plant can be dissolved into tiny living corpuscles, which he called “cells,” because they often had the appearance of a filled honeycomb. A year later Schwann proved, in Johannes Müller’s laboratory, that the higher animal also is a product of these cells. The cell was recognised as the living unit that composed the oak and the rose, the elephant and the worm. Man himself, in fine, was but a pyramid of these cells—or, to speak more accurately (as each cell has its own life), an immense community of cells, a cell-state.
Virchow had, as we saw, laid the greatest stress on this last and most important deduction from the cell-theory a short time before. He looked upon every individual man as a mysterious plurality—a plurality of cells. Pathology, the science of disease, must take account of this. Health was the harmonious co-operation of the cell-state; disease was the falling-away of some of the cells to special work that injured or destroyed the whole community. This conception had inaugurated a new epoch in medicine, making it a consciously ministering art in the service of the living human natural organism. The Darwinian had now the task of showing the validity of this conception in his own province. The genealogical tree of the animals and plants must at once be drawn up in the form of a genealogical tree of the cell. The cells had combined to form higher and higher communities, and each higher species of animal or plant was in reality one of these social constructions. But this complexity was only found in the upper branches. The lower we descend, the simpler we find organisms. The lowest forms of life represent cruder, simpler, and more primitive cell-structures. And the final conclusion was that all the cell-communities or states must have been evolved from unattached individuals whose whole body consisted of a single cell. We cannot strictly call these lowest forms of life either animals or plants; they can only be likened to the single cell. Though Haeckel himself did not know it at the time, all his pretty radiolaria at Messina belonged to this category. The whole swarm of bacilli and bacteria fell into this world of the “unicellulars.” Haeckel’s words threw a brilliant light on the question. Not only the simplest forms of 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.
Ernst Haeckel, 1880.
Reproduced from the Natürliche Schöpfungsgeschichte.
He opens with a vigorous protest that there can be no quarrel about the materialism of science with the “spiritual” and the “privately-orthodox.” Such people must regard all investigation of “this world” as aimless. The only thing of value for them is “the next world”; the best attitude towards this life is as crass an ignorance as possible, and so all science is worthless. The words are so sharp that he was interrupted and had to explain that he was not attacking anybody personally. He was only speaking “with the candour of a scientific worker, who is in the habit of calling things by their proper names.” (At this point there was some applause.) Hence he is not speaking of materialism, he says, on that account, but because of certain objections from men of science, who said that philosophic speculation led us out of our way. Schleiden had branded the theory of man as a cell-state, the conception of man as, not an absolute, but a federal unity, as materialism. But this conception is not a philosophical theory at all; it is a fact. It is a piece of scientific truth, like the law of gravitation. He recurred to the old and often-quoted definition: the kind of research that brings such facts to light has nothing whatever to do with philosophy. On the other hand, “materialism,” in so far as it expresses a general theory of the world, is a philosophy. Hence the simple investigation of facts as such can neither be dubbed materialistic nor said to have a philosophic tinge.