Studies upon the life cycles of the bacteria ... / by F. Loḧnis.

  • Löhnis, F. (Felix), 1874-1930.
Date:
1921-
Catalogue details

Licence: Public Domain Mark

Credit: Studies upon the life cycles of the bacteria ... / by F. Loḧnis. Source: Wellcome Collection.

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    “that all bacteria formed merely stages in the life history of a group of organisms with an extremely complicated life cycle.” The most important contributions to our subject, however, in modern British literature are those of Hort (1915-1917) and his collaborators, to which we will have to refer frequently. It was with good reason that Adami (1916), after having become acquainted with these new observations, raised the question: Have we all these decades been wrong in our faith, that bacteria are the simplest of all living forms of life, pos¬ sessed of asexual multiplication by fission only? May there not be intercalated other phases in the life history of the schizomycetes? The German and Austrian bacteriological literature shows an interesting change from monomorphistic to extremely pleomorphistic views, then back to the rigorously monomor- phistic standpoint of R. Koch and his pupils, and at last an almost general acceptance of the moderate pleomorphism as it has always been taught by French bacteriologists. Although there is no special discussion upon this problem, the monomorphistic point of view is already clearly discernible in Ehrenberg’s (1838) as well as in F. Cohn's (1853) early publications. It is, however, by no means, that strict monomorphism which was advocated 20 years later by the same author. Bad. termo, e. g., was declared to be able to grow in globular, curved, or rodlike form. The extreme pleomorphism, on the other hand, promulgated especially by Hallier (1865- 1878) and by Liiders (1866), undoubtedly was not supported by sufficiently reliable observa¬ tions, but it can also not be considered fair to condemn summarily all what has been written by Hallier as being “scientific nonsense” (Winter, p. 33), or as merely belonging to the scientific “chronique scandaleuse” (DeBary, p. 137). As much of this work was based on long con¬ tinued direct microscopic studies, some of his results, though obtained with impure cultures, still retain their value, and will even regain new interest in connection with other data which are to be discussed in Chapter II. The same holds true in respect to various facts observed by Karsten (1869). This author, as well as H. Hoffmann, already in 1869 and with good reason rejected HaTlier’s erroneous assumption of a direct connection existing between fungi and bacteria. Hoffmann's publication is of special interest, because it contains the first drawings of branched bacteria, which later were rejected by the extreme monomorphists. Morphological changes of single bacteria cells have been studied directly under themicroscope by Rindfleisch (1872), as well as by Billroth (1874). The latter author has been repeatedly called the champion of the older pleomorphism, usually on account of no other reason than that he named all bacteria together Coccobaderia septica. But he left it explicitly (p. 35) for the botanists to decide, whether or not the different forms which he observed were merely different types of growth of this one Coccobaderia septica or whether several genera and species should be made. It is a similar case with Ndgeli’s standpoint. Usually the following sentence (1877, p. 20) has been quoted as convincing proof of his alleged error: Icb habe seit zehn Jahren wohl tausende von verschiedenen Spaltpilzformen untersucht, und ich konnte (wenn ich Sarcina ausschliesse) nicht behaupten, dass aucb nur zur Trennung in zwei specifiscb verscbiedene Formen N6thi- gung vorbanden sei. However, the following statement in the same publication (1877, p. 22) also must be taken under consideration: Wenn icb sage, dass die uns bekannten morpbologiscben Eigenscbaften der Spaltpilze und ihr Vermogen, ver¬ scbiedene Zersetzungen zu bewirken, eine generiscbe und specifiscbe Unterscheidung nicbt recbtfertigen, und dass selbst die Moglicbkeit vorliege, alle Formen in eine einzige Species zu vereinigen, so liegt es mir docb fern, diese Bebauptung wirklicb auszusprecben. In einer Sacbe, in welcber die morpbologische Beobacbtung und der pby- siologiscbe Versucb den Forscber nocb so sebr im Stiche lassen, ist es iiberbaupt gewagt, eine bestimmte Ansicht auszusprechen. In his later work (1882, p. 130) he defends himself against those who assert that he be inclined to consider all bacteria one species. But at the same time he points out that also accord¬ ing to his new experiments with pure cultures, all morphological and physiological qualities of