The division and post-fission movements of bacilli when grown on solid media / by G.S. Graham-Smith.

  • Graham-Smith, G. S. (George Stuart), 1875-1950.
Date:
1910
Catalogue details

Licence: In copyright

Credit: The division and post-fission movements of bacilli when grown on solid media / by G.S. Graham-Smith. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    ohe edges of the cover-glass sealed to the slide all round by means of a small quantity of melted vaseline. The specimen was then transferred to the stage of a microscope placed within a Nuttall’s microscope thermostat, kept at 37° C. Such a preparation can be continuously studied for many hours or days. This method is applicable to motile as well as non-motile organisms. The bacteria cannot lie otherwise than horizontally and in the same plane. They are all necessarily in optical contact with the cover-glass and are free to grow (horizontally) without the restrictions imposed by surrounding them with jelly or the freedom to drift allowed if liquid is used. 2. Growth in the depth. In order to study growth in the substance of the agar a small quantity of bacterial emulsion was mixed with melted agar at 40° C. and the latter poured on a slide. When the agar was just beginning to set a cover-glass was placed on it and the specimen finished as in the case of surface preparations. 3. The bacterial emulsion. The emulsion of the bacterium to be investigated was invariably made from a 12 to 18 hour sloped agar culture. In making the emulsion sterile tap water was generally used. Even in the young cultures which were made use of a certain proportion of the organisms were found to be dead, or at any rate incapable of growth under these conditions. This was more frequently the case if a portion of the growth from the surface of the agar culture was used for making the emulsion. The proportion of dead bacteria was much smaller if the growth occurring in the water at the bottom of the tube was used. 4. The choice of an organism for observation. The observations were usually made with a Zeiss 4 mm. objective and an 8 compensating ocular, artificial light being used for illumination, with sub-stage lowered and a narrow diaphragm. For satisfactory observations a part of the preparation should be sought for where the bacteria are so thinly scattered that only a few are within the field at the same time (see Plate VI, Fig. 13). A well isolated organism, which looks capable of growth and which is lying in a 2—2