We might, according to Büchner, dismiss these orthodox thinkers with the assumption “that the first elements endowed with the idea of the race have been present in space from all eternity in formless chaos out of which the universe slowly consolidated, and accidentally developed after the formation and cooling of the planet wherever conditions were favorable.” But such fictitious reasonings or pretexts, Büchner assures us, are not necessary. Scientific facts, he says, indicate with great distinctness that the organic beings on our earth owe their generation and propagation to the co-operation of physical substances and forces alone. After such an introduction we proceed with interest to learn about these scientific facts, but how great is our disappointment when we find that Büchner here takes up an entirely different subject, which, if it has any connection with the question at issue, goes to prove just the reverse of what he intended. The whole long series of facts to which he now points is, in a few words, nothing but Darwin’s theory in a paleontological light. What Büchner shows by numerous examples from fossil deposits, is that higher forms of animals and plants have slowly developed from lower forms. But what has this fact to do with _generatio spontanea_? That higher forms have developed from lower forms only confirms the dictum that life implies life; in other words, supports Harvey’s law. But it is something else that Büchner should have demonstrated. He should instead have shown us that the first organisms owe their existence to physical forces alone. But on this subject he uses only vague expressions, void of any real significance, about the slow cooling off of the earth; about the length of the geological periods, and about favorable conditions; but not a line to explain what this word “favorable” stands for. Although Büchner here inadvertently supports something different from what he intended, his remark nevertheless remains true that the present mode of propagation proves nothing in regard to the generation of the first organisms. Other scientists have gone further than Büchner and believed themselves justified in extending Harvey’s law to cover not only the present time, but all times. And the problem as to the first organisms has been answered in various ways. Sir William Thomson believes that such might have come to the earth with some meteoric stone, possibly a moss-clad fragment, from another planet in the universe that had met with a cosmic catastrophe, and, further, he has even tried to show that this hypothesis does not involve any physical impossibility. Opinions seem to be divided, then, as to the validity of Harvey’s law. This again indicates a deficiency in the law itself, and it is true that such a deficiency really exists. _Harvey’s formula is not a law; it is, as yet, only an empirical hypothesis._