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LITERATURE REVIEW.

SECTION I. (Pages 1-15).

I. SPALLANZANI, LAZZARO: Saggio di osservazioni microscopiche, relative al sistema della generazione di signori Needham e Buffon. Modena, 1765.

II. SCHEELE, CARL WILHELM: Anmärkningar om sättet att conservera ättika. (Kongl. Vetenskaps Academiens nya Handlingar. Tom. iii. Stockholm, 1782, p. 120.)

III.-APPERT: Le livre de tous les ménages ou l'art de conserver pendant plusieurs années, toutes les substances animales et végétales. 4ième éd. Paris, 1831.

IV. SCHULZE, FRANZ: Vorläufige Mittheilung der Resultate einer experimentellen Beobachtung über generatio æquivoca. (Poggendorff's Annal. d. Phys. u. Chem. Bd. xxxix., 1836. No. 11, p. 487.)

V.-CAGNIARD LATOUR, CHARLES: (1) His communication appeared in the Parisian "L'Institut" on 23rd November, 1836.

(2) Mémoire sur la fermentation vineuse. (Laid before the Académie des Sciences on 12th June, 1837; published in Compt. rend. de l'Acad. des Sc., Tom. iv., 1837, p. 905, and in Annal. de Chim. et Phys., Tom. Ixviii., 1838, p. 206.)

Cagniard Latour states in the above that yeast is organised matter and that it is probable that the formation of carbonic acid and of alcohol is caused in some way by the growth of the yeast.

VI.—SCHWANN, THEODOR.

In September, 1836, Schwann demonstrated before the Naturforscher-Versammlung in Jena that the yeast fungus described by him is the cause of alcoholic fermentation.

In the publication which appeared in 1837 under the following title

(1) Vorläufige Mittheilung, betreffend Versuche über die Weingärung und Fäulnis (Poggendorff's Annal. d. Phys. u. Chem. Bd. xli., 1837, Nr. 5)

he also communicates the discovery that putrefaction is caused by living corpuscles. His words are:

". . . Then putrefaction must be thus explained, that these germs, while developing and while feeding at the expense of the organic substance, cause in it a decomposition of such a nature that it gives rise to the phenomena of putrefaction. . . .'

(2) Mikroskopische Untersuchungen über die Übereinstimmung in der Struktur und dem Wachsthum der Thiere und Pflanzen. Berlin, 1839.

In the above research, Schwann again establishes that yeast is a fungus, and that it causes fermentation. He further communicates his discovery of yeast spores and lays the foundation of the science of antiseptics. He expresses himself thus:

"... All conceivable proofs point to the ferment particles being fungi. Their form is that of the fungi, their structure is like that of the fungi, for they consist of cells many of which again contain young cells; they grow like fungi by producing new cells at their ends, they propagate themselves like fungi, partly by separation of single cells, partly by production of new cells in the existing ones, and by the bursting of these mother cells. Now, that these fungi are the cause of fermentation follows: first, because they constantly occur in fermentation; second, because fermentation is stopped by all processes which evidently kill the fungi, e.g., boiling heat, potassium arsenate, etc. . . ."

VII.-KÜTZING, FRIEDRICH: Mikroscopische Untersuchungen über die Hefe und Essigmutter, nebst mehreren anderen dazu gehörigen vegetabilischen Gebilden. (Journ. f. prakt. Chemie, Jahrg. 1837, Bd. ii., p. 385.)

VIII.-V. LIEBIG, JUSTUS: (1) Die organische Chemie in ihrer Anwendung auf Agrikultur und Physiologie. 1. Aufl., 2. Theil. Braunschweig, 1840.

Liebig had as early as 1839 expressed the leading principles of his

theory in a treatise: "Über die Erscheinungen der Gährung, Fäulnis und Verwesung und ihre Ursachen". (Poggendorff's Annal. d. Phys. u. Chem., 1839, pp. 106-150.) He expresses the following views on p. 142: "The form and condition of the insoluble precipitates in fermentation have led to a very strange conception of fermentation on the part of many physiologists. When beer and wine yeasts are distributed in water and looked at under a good magnifying glass, transparent, flat, compressed corpuscles are seen, which sometimes, attached to one another in chains, assume the form of growths; in the eyes of others they are similar to many infusoria. It would certainly be an extremely noteworthy phenomenon if plant substance and albumen, which are precipitated in a changed condition in the fermentation of beer and of plant juices, were to assume a geometrical form when deposited, since these bodies have never been observed in the crystallised condition. Now this is not the case; they precipitate, like all substances which do not possess crystalline properties, in the form of spherical corpuscles, which either swim about free or are connected with others. These investigators were misled by this form to regard the ferment as consisting of animated organic beings, whether plants or animals, which in their development assimilate the constituents of sugar and excrete them again in the form of carbonic acid and alcohol; they explain the decomposition of the sugar and the increase of the mass of the added ferment in beer fermentation. This view confutes itself; in pure sugar water the so-called seeds disappear with the plants on fermentation; fermentation takes place, the decomposition of the sugar ensues with that of the ferment, without any development or reproduction of seeds, plants or animals being observed, which is regarded by these investigators as the cause of the chemical process." v. Liebig, JustUS: (2) Ueber die Gährung und die Quelle der Muskelkraft. (Sitzungsber. der Königl. bayer. Akad. d. Wissensch. ii., 1869, pp. 323 and 393, and Annal. d. Chemie u. Pharmacie, Bd. cliii., 1870, pp. 1 and 137.)

In the above treatise, Liebig's last opinion on the Pasteur fermentation theory is expressed. It may be inferred from the following two quotations:-

Page 2: "From the chemical standpoint, which I should not like to give up, it is an act of life,' 'a condition of motion,' and taken in this sense Pasteur's view is not opposed to mine nor does it disprove mine".

Page 6: "It might be that the physiological process stands in no other relation to the process of fermentation than to produce the substance in the living cell, which, by an action peculiar to itself similar to that of emulsin on salicin and amygdalin, causes the breaking up of the sugar and other organic atoms; the physiological

process would be necessary in this case to produce the above substance, but with the fermentation as such it would have no further connection".

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Hoppe-Seyler in his Physiologische Chemie," Berlin, 1877, expresses substantially the same view as that of Liebig's given above and that given formerly by Traube. According to HoppeSeyler, fermentation is caused by a purely chemical ferment contained by the yeast. On page 115 he says: "Liebig has shown very clearly the untenable and harmful nature of Pasteur's views, yet his deductions received little attention ".

IX.—MITSCHERLICH, EILHARD: (1) Über die chemische Zersetzung und Verbindung vermittelst Contactsubstanzen, given as a lecture in the Kgl. Akad. d. Wissensch. Berlin; a reference is to be found in Bericht über die zur Bekanntmachung geeigneten Verhandlungen d. Kgl. preuss. Akad. d. Wissensch, zu Berlin, Dec., 1841.

On p. 390 he writes as follows: "The sugar into which cane sugar changes, when yeast is added to a solution of the latter, appears to be different to grape sugar; the author has not been able to crystallise it, and it polarises light much less than the same quantity of grape sugar; its formation is very remarkable; it is in fact a substance mixed with the yeast spherules, and can be removed by water extraction, and a clear solution of it causes the transformation of cane sugar into this kind of sugar".

(2) Another communication is to be found ibid., Feb., 1843.

He exhibited on this occasion some engravings which represented among other things the increase of top yeast. The figure given on p. 192 of my book is a reproduction of one of these engravings, which, however, so far as can be found, were never published all together. Some of the figures reproduced are to be found in Mitscherlich's "Lehrbuch der Chemie," 4. Ausg., Bd. i., 1844; and in Regnault, "Cours élémentaire de chimie," 2me éd., tom. iv., p. 179; further in Jos. Bersch, "Gährungs-Chemie für Praktiker," 1. Teil, Berlin, 1879, p. 60, etc.

X.-SCHROEDER, H., und VON DUSCH, TH.: Ueber Filtration der Luft in Beziehung auf Fäulnis und Gährung. (Annal. der Chem. und Pharm. Bd. lxxxix., Heft 2, 1854, p. 232.)

XI.—PASTEUR, LOUIS: (1) Mémoire sur la fermentation appelée lactique. (Compt. rend. de l'Acad. des Sc., Tom. xlv., 1857, p. 913.)

The above memoir is Pasteur's first research on this subject, and treats, as the title shows, of lactic acid fermentation. In the same year he published his first paper on alcoholic fermentation, viz. :PASTEUR, LOUIS: (2) Mémoire sur la fermentation alcoolique. (Ibid., p. 1032.)

He arrives at the same results here as his predecessors, Schwann, etc., viz., that yeast splits up the sugar in consequence of its vitality. He then publishes a series of smaller papers in the "Compt. rend."; all matter referring to alcoholic fermentation is collected in a larger paper, viz. :—

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(3) Mémoire sur la fermentation alcoolique. (Ann. de Chim, et de Phys. 3 Sér., Tom. xlviii., 1860, p. 323.)

The publications in the "Compt. rend." are continued, and among these might be mentioned:

Nouvelles expériences

(4) De l'origine des ferments. relatives aux générations dites spontanées. (Compt. rend. de l'Acad. des Sc., Tom. 1., 1860, p. 849.)

in which he controverts the doctrine of generatio aequivoca, and :

(5) Fermentation butyrique.

Animalcules infusoires

vivant sans oxygène libre et déterminant des fermentations. (Compt. rend. de l'Acad. des Sc., Tom. lii., 1861.)

in which, for the first time, the doctrine of anaerobiosis is put forward.

For some years he continues to fight against the doctrine of generatio æquivoca; his particular opponents on this point are Pouchet and Joly; after him his pupils, especially Chamberland and Roux, take up the matter.

Pasteur at the same time upholds his theory of fermentation till the beginning of the seventies; his writings in this connection are to be found in the "Compt. rend." His opponents are chiefly Liebig, Traube, Brefeld, Berthelot and Cl. Bernard.

(6) Études sur le vin. Paris, 1866.

(7) Études sur le vinaigre. Paris, 1868.

(8) Études sur la bière. Paris, 1876.

In the three researches named, which with (4) must be looked upon as the chief works of Pasteur in the science of fermentation, is to be found what he has accomplished for these branches of industry; in (8), especially, there is a collation of his researches on fermentation and the organisms of fermentation as a whole, and the book practically ends his researches on this subject.

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