been proved that the origin of monera by spontaneous generation is impossible; but looked at from a strictly scientific point of view, it is not in the least more likely than the similar origin of infusoria. Frohschammer rightly remarks with reference to this, "At any rate it is not yet proved that proteid matter forms itself anywhere in nature from inorganic matter without the mediation of organic forces. And even if we should succeed in producing such albuminous compounds by experiment, yet even then there is no proof that they also originate by themselves in nature, because in experiment there is still the systematic intelligent action of the investigator, a systematic action, which, if we do not fall back on the action of the Creator,"—and Hæckel is the last person to do this, -"cannot always be replaced in nature by chance or by the relations of things, even if all the substances and forces which the experimentalist has at his disposal are present. And supposing that albumen did at any time. form itself in nature, it would not prove that germs or cells, single-celled organisms, however simple they might be, formed themselves from it of their own accord. Up to this time, so far as we know, no organism has been inorganically or empirically formed, even from albumen which itself has been formed in organisms. This is hardly likely to happen more easily or to be more possible in nature, for, on the contrary, general experience shows continually that albumen cannot even exist apart from a living organism, but dissolves and decays, instead of forming itself into cells or organisms.'

"1

1 Das Christenthum, p. 62.

Hæckel's theory that albuminous protoplasm could "individualize" itself into monera, in the same way as the mother-liquor of crystals individualizes itself in crystallization, is rather venturesome. The organic cells and the crystals are essentially different, in that "the cell does not only grow by additions to the outside, but primarily from within; that it does not lose its activity like the crystal at the moment of its formation, but creates from within itself new forms like itself, and that, alike in its dimensions, its extent, and its duration in time, it is limited by its own individual formative and living impulse." "Organic bodies," says K. E. von Baer, "are not only changeable, but they are the only things that change themselves. The crystal and the rock are no doubt also exposed to final destruction, but the destruction does not come from within. Damp, heat, chemical and physical forces, in general help to wear them away. Were they placed in an isolated spot in the universe, they would last for ever; for what is lifeless cannot die, it is only destroyed by the outside world. On the other hand, organic bodies destroy themselves, they are not only subjected to constant change, but their whole development is a progress towards death."2 Virchow also mentions some essential differences between the organic individual and the crystals, although he disputes the assumption of the so-called vital force. "The crystal can grow indefinitely if it finds the conditions and the matter for its growth. On the other hand, with the living being, the internal law of its

1 Huber, Die Lehre Darwins, p. 14. Michelis, Hackelogonie, p. 100. 2 Reden, Petersburg 1857, i. 38; see Huber, Op. cit. p. 15.

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destiny (innere Zweck) is also the limit of its external development. Space and time have a meaning and a value only for the living being; for only the living being carries within it the power of self-preservation and self-development, only the living being loses itself if it is not determined from within to attain to a certain development within a certain period. Thus the individual carries its aim and its measure within itself; thus it proves itself to be a real unity, instead of the merely notional unity of the atom."1

After what has been said, we may at all events consider that recent researches have shown that the theory of spontaneous generation has been proved to be not inadmissible only in the case of the simplest and smallest organic being; that, according to most scientific men, however, no organic being comes into existence by spontaneous generation. But if the idea of a contemporary spontaneous generation is inadmissible, or at least very problematical, may we not still assume that spontaneous generation did occur in the earlier periods of the earth's history?

"Now-a-days," says Burmeister, "when plenty of beings capable of reproduction exist everywhere, there is no need that new ones should form themselves from

1 Vier Reden über Leben und Kranksein, p. 49; see Huber, Op. cit. p. 22. Semper, Der Hackelismus in der Zoologie, pp. 29, 34, calls Hæckel's "carbon theory" "an entirely unjustified hypothesis," which, he says, seems to have originated because the modern name for organic chemistry is the chemistry of carbon compounds. The two supporters of this theory, Hæckel and Seidlitz, "forget that organic chemistry is not in the least synonymous with the chemistry of the living organism; the former deals only with dead, the latter only with living organic bodies. Unfortunately we know at present very little of the latter, but we know enough to be able to say that its laws need by no means be identical with those of organic chemistry."

matter; and, perhaps, the original material from which they could form themselves is wanting, as by far the greater part of the organic substance now existing is already contained in living organisms, and the only provision for the existence of new individuals appears to be by means of procreation. But in the early ages of organization all this was different, and therefore the course of generation was probably different also."1 Hæckel reminds us that at the time when, after the origin of water in a liquid state on the cooled crust of the earth, organisms were first formed, the immeasurable quantities of carbon which we now find deposited in the coal measures existed in a totally different form; they were probably for the most part dispersed throughout the atmosphere in the shape of carbonic acid. The whole composition of the atmosphere, including even its density and electrical conditions, was therefore very different from at present; and, in like manner, the chemical and physical nature of the primeval ocean, its temperature, density, saltness, etc., must have differed widely from that of the present ocean; so that we cannot, at least, contradict the supposition that at that time, under conditions quite different from those of to-day, a spontaneous generation, which now is perhaps no longer possible, may have taken place."

We may admit the possibility, but the supposition is not scientifically probable. Frohschammer justly says with reference to this: "As in these days, according to our experience, cells and germs only originate in organisms, we have no right to suppose,

1 Gesch. der Schöpfung. p. 287. 2 Nat. Schöpfungsgeschichte, p. 303.

without certain proof and sure warrant, that it was different in early days, in the beginnings of organic nature. This is a principle which is generally insisted on in natural science in the present day, and which, therefore, ought not to be discarded in this case without very good reasons." Men of science can make no objection to the following angry words of Quenstedt's, "To the savant, to understand means to see, and he can only draw conclusions on this basis. If, now-a-days, even the smallest plant cannot come into existence without a germ, what thoughtful savant would venture rashly to assert that the whole beautiful vegetable and animal world, up to man, had been generated only in the dead earth? But to many the idea that the Creator has power to breathe life into the dead lump of clay is so unwelcome, that they would rather embrace the wildest dreams in order to prove themselves apparently right. Yes, they say, it is very easy to explain why the earth can now-a-days bring forth no living creature; now it is in its old age, but when it was young, things were different. It is amusing to see how these men, who usually subject to the sharpest criticism the slightest instinctive revolt of the mind against abstract laws of nature, tell us when they come to the beginnings of organic life, how then, in the bosom of the old formations, every speck of mud suddenly teemed with life, and describe the unwearied creative might of the dead earth. Here we have a specimen of the narrowness of man's spirit; he believes that nothing can exist but what he can conceive. When philosophers go this length we may perhaps

1 Das Christenthum, p. 64. VOL. II.

2 Sonst und Jetzt, p. 233.

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