The micro-organisms of fermentation practically considered / by Alfred Jörgensen.

  • Jörgensen, Alfred, 1848-1925.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: The micro-organisms of fermentation practically considered / by Alfred Jörgensen. Source: Wellcome Collection.

    60/198 (page 38)
    CHAPTER III. THE SCHIZOMYCETES, OR BACTERIA. The more our knowledge of tliese small organisms becomes enlarged the more difficult it is to give to tbem a general definition. Tbey are known in all forms, from the finest points or spheres to green algal-like threads, and they appear very nearly in all possible places under the most various couditions as the cause of putrefaction or decay (Saprophytes), of diseases (pathogenic forms), and of fer- mentation (zymogenic forms). The first knowledge of these forms was obtained in con- sequence of small quantities of different substances being placed mider the microscope and examined with high powers. Li putrefying flesh there were found very small spherical bodies, which clearly multiplied by transverse division (micrococci, “ bacterium termo ”) ; in sour milk there oc- curred short rod-like bodies (bacteria) ; in rotting vegetable material larger spherical bodies (macrococci) and long, fine threads (bacilli and leptothrix) were found ; m saliva, on the contrary, there were seen very fine, wavy, almost broken threads (spirilla, spirochseta), &c. On this account it was convenient to provisionally hold fast to these forms, and to describe them as so many distinct species ; and Cohn par- ticularly has earned credit in this respect, since to him is due the first systematic Classification of bacteria. We will next consider the forms and the individuals somewhat more closely. As before stated, the bacteria in their simplest form occur as spherical bodies of different sizes, down to bodies so minute that they can scarcely be seen with the strongest powers, and only give evidence of their existence as organisms by their multiplication through fission. Bacteria are accordingly divided into macrococci