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spontaneous generation of infusoria has received its death-blow, as Huxley says, by these experiments of Pasteur's. The famous Paris Academician Flourens said, as early as 1864, “No one thinks that insects are spontaneously generated since Redi (1688), that intestinal worms are spontaneously generated since Van Beneden (1853), that infusoria are spontaneously generated since Balbiani (1862), and since Pasteur it is not asserted of any animals.”! This is going too far. No doubt most of the leading savants of the present age declare themselves decidedly against the assumption of spontaneous generation, and one of the defenders of

having a long tubular neck with it. He then boiled the liquid, and bent that long neck into an S shape, or zig-zag, leaving it open at the end. The infusion then gave no trace of any appearance of spontaneous generation, however long it might be left, as all the germs in the air were deposited in the beginning of the bent neck. He then cut the tube close to the vessel, and allowed the ordinary air to have free and direct access; and the result of that was the appearance of organisms in it, as soon as the infusion had been allowed to stand long enough to allow of the growth of those it received from the air, which was about fortyeight hours. The result of M. Pasteur's experiments proved, therefore, in the most conclusive manner, that all the appearances of spontaneous generation arose from nothing more than from the deposition of the germs of organisms which were constantly floating in the air. To this conclusion, however, the objection was made that if that were the cause, then the air would contain such an enormous number of these germs that it would be a continual fog. But Pasteur replied that they are not there in anything like the number we might suppose, and that an exaggerated view has been held on the subject; he showed that the chances of animal or vegetable life appearing in infusions depend entirely on the conditions under which they are exposed. If they are exposed to the ordinary atmosphere around us, why, of course, you may have organisms appearing early. But, on the other hand, if they are exposed to air from a great height, or from some very quiet cellar, you will often not find a single trace of life.” -Huxley, On our Knowledge of the Causes of the Phenomena of Organic Nature, Six Lectures, London 1863, p. 78 seq. Cf. Aug. Müller, L'eber die erste Entstehung organischer Wesen, Berlin 1869, p. 9.

1 Examen du Livre de M. Darwin, pp. 67, 121.

? Ehrenberg, Rudolf Wagner, Joh. Müller, Liebig, Brown, Virchow, Schleiden, Unger, Herm. Hoffmann (Untersuchungen, etc., p. 4), F. Cohn

this theory admits that those who agree with him form only a small and unimportant party, and that “ almost all eminent men of science” are opposed to it.' But very thoughtful men, like Th. H. Martin, are contented with asserting that no doubt the assumption of spontaneous generation has been made extremely improbable ; but that all the conditions of a perfectly sure, inductive experiment have not yet been fulfilled. For the present we must be content with this statement, and the more so, as in recent times Pasteur's view has been decidedly disputed by many—in England, especially by H. Charlton Bastian ; ' and it has been said that experiments have proved that organisms can certainly originate in organic infusions, and that they may very likely originate in solutions of salts.

Therefore D. F. Strauss' observation : “It is certain that living beings still form themselves partly from inorganic, partly from dissimilar organic substances, under certain circumstances; the so-called infusoria forming themselves when water is poured not only on animal and vegetable, but also on mineral bodies, and (Bakterien, p. 31), and others. In France, Flourens, Milne Edwards, de Quatrefages, Claude Bernard, Dumas, and others. Cf. Ulrici, Gott und die Natur, p. 366. Valroger, La Genèse, p. 38.

1 Thus Giebel, Tagesfragen, p. 204. In France, besides Pouchet, N. Jolly and Ch. Musset believe in spontaneous generation ; in Germany, Schaaffhausen. K. Vogt, who formerly did not believe in spontaneous generation (see Natür. gesch., p. 148 ; cf. Vorlesungen, ii. 253), now says that he does not consider the subject as settled, even after Pasteur's experiments. (See his preface to Huxley's above-quoted book, p. viii.)

? Les Sciences, p. 97.

3 The Beginnings of Life, London 1872. Evolution and the Origin of Life, London 1874. Cf. Saturday Review, vol. 34 (1872), p. 731 ; and for the controversy between Bastian and Huxley, see vol. 30 (1870), p. 550 ; vol. 32 (1871), p. 152. Other English savants have also declared themselves opposed to Bastian's theory ; see Popular Science Review, April 1876. Zöckler, Gesch. der Beziehungen, etc, ii. 722.

entozoa forming themselves in animal bodies," was one of those which caused Humboldt to blame in very strong terms Strauss' “scientific levity;"1 although he usually shows great sympathy for his theological opinions. Strauss expresses himself much more cautiously in his last book ;? he only says there that the question of the generatio equivoca has occupied natural science again recently, although, because of the difficulty of proof, no generally accepted decision has been reached.

A fresh attempt has been made by Hæckel to proye the spontaneous generation of organisms. He says that it is the case only with one class of organic beings, the so-called monera. These are, he says, organic beings of the simplest description; their entire body, which is at most as large as a pin's head during life, is nothing more than a shapeless mobile lump of jelly (protoplasm). The monera cannot “exactly be called either animals or plants ;” “strictly speaking, they do not deserve the name of organisms at all,” for they are not composed of organs, but consist entirely of shapeless, simple, homogeneous protoplasm,—that same proteid carbon - containing compound which, in endless modifications, is found in all organisms, as the essential and never-failing basis of the phenomena of life. It propagates itself by subdivision. When such a little spheroid has attained a certain

i Correspondence with Varnhagen von Ense, p. 117: “There is one thing which displeases me in Strauss, and that is the scientific levity with which he treats the question of the formation of organic out of inorganic matter; he even apparently sees no difficulty in believing that man was formed from Chaldean primeval mud.”

2 Der Alte und der neue Glaube, p. 169.

3 Natürliche Schöpfungsgeschichte, pp. 164, 305. Das Leben in den grössten Meerestiefen, p. 33. Anthropogenie, p. 377.

size by the assimilation of foreign albuminous matter, it falls into two or more pieces, which again, by simple growth, become like the parent body. “Perhaps the most remarkable of all the monera” have been found in the fine calcareous mud which has been dredged up in the course of the deep-sea researches so largely instituted of late years. They are sometimes roundish formless lumps of jelly, sometimes a gelatinous network covering fragments of stone and other objects. These “ beings living in the deep sea,"—if these little lumps of jelly can be really considered as living beings, were called Bathybius by Huxley in 1868, and in honour of Hæckel, Bathybius Hæckelii. Unluckily it is very likely, although Hæckel does not mention it, that the Bathybius will have to be removed from the list of living beings. At least Huxley asserted, in an English periodical in August 1875, that he feared “the thing to which I gave that name is little more than sulphate of lime, precipitated in a flocculent state from the sea-water by the strong alcohol in which the specimens of the deep-sea soundings which I examined were preserved ;”1 and Dubois Raymond says, “Since then the scientific existence of the Bathybius Hæckelii has become as precarious as that of its supposed fossil model, the Eozoon Canadense."Johannes von Nanstein even says, “The Bathybius only exists in the dark depths of scientific superstition.” 3

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1 Nature, 19th Aug. 1875. Cf. Annals and Magazine of Natural History, ser. 4, vol. 16 (No. 95, Nov. 1775), p. 325. C. Semper, Der Hæckelismus in der Zoologie, Hamburg 1875, p. 30.

2 Ueber die Grenzen des Naturerkennens, 4th ed. 1876, p. 43. 3 Das Protoplasma, p. 178. Cf. K. A. Zittel, Die Kreide, Berlin 1879, p. 27.

Hæckel therefore thinks that the monera originate by spontaneous generation. He reminds us that chemists have recently succeeded in doing what was asserted fifty years ago to be impossible, that is, in producing carbon compound, or so-called “organic” substances, as urea, alcohol, acetic acid, and so on, from inorganic substances. Therefore there is every probability that sooner or later we shall succeed in producing artificially the proteid compounds, or protoplasm itself. We may therefore assume that in nature also there may be formed from inorganic substances first some simpler carbon compounds, and from these, protoplasm capable of life; if this exists, it only needs to individualize itself in the same way as the mother liquor of crystals individualizes itself, and the moneron is there.

But Hæckel himself admits that “this event must remain a pure hypothesis so long as it is not directly observed or repeated in experiments.” I He adds that the process of the spontaneous generation of monera would in any case be very difficult to observe, and could hardly be verified with undoubted certainty, even if it still happened daily and hourly. But it cannot be difficult to repeat the process by means of an experiment, if it is as simple as Hæckel makes it. “The special conditions of existence,” under whose influence the Bathybius originates, according to Hæckel, may be artificially produced; but yet he has not responded to the challenge to fabricate a Bathybius.?

We may concede this much to Hæckel ; it has not

1 Natürliche Schöpfungsgeschichte, p. 309. Cf. Anthropogenie, p. 377. 2 Ausland, 1870, 1091.

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