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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    outgrowths, in most of which knots have been formed at various places, and all of which possess secondary lateral processes. Plate IV, Fig. 12 illustrates some young deep anthrax colonies. These consist of central knots and numerous wavy radiating processes. This preparation was made with very dilute agar which limits the growth to a much smaller degree than does ordinary agar. Plate IY, Fig. 13 shows deep and superficial growth in the same colony. The colony first developed just below the surface of the agar and grew in the typical manner. This portion is seen in the lower left hand part of the photograph. Later a portion of the colony reached the surface and produced on it a typical superficial wavy growth seen in the upper and right hand portions of the photograph. In fluid media long chains occur, but owing to their growth being unrestricted they produce neither loops nor tangles. The conditions seen in stained preparations and in “ contact ” preparations and the observations on living specimens just described all tend to show that in the “ loop forming ” group, as illustrated by B. anthracis, although the protoplasm becomes segmented and numerous bacilli are produced, the membrane or capsule surrounding the chain apparently remains continuous, and keeps the newly formed bacilli closely connected with one another. This capsule is seldom completely ruptured, and each colony therefore consists of a single uninterrupted chain of bacilli. Under the conditions of observation, or on surface cultures, the bacilli are only free to grow horizontally. As growth is taking place, not only at the ends, but in all parts of the chain at the same time, curves ultimately developing into loops are formed in order to accommodate the rapidly increasing length of the chain. If the centre of a piece of string is placed between two parallel glass plates, separated from each other by a distance equal to the diameter of the string, and the string is gradually pushed between the plates from fixed points on each side, the changes which occur in a young colony of a loop forming bacillus are to some extent reproduced. In the depth loop formation is hindered by the consistency of the medium and consequently the chain as it grows tends to develop tangles, which subsequently become knots, and twisted lateral outgrowths. Group II. The “folding” group. During the first stages of growth on the surface the original bacillus grows in length and divides into two rods of equal length, separated from each other by a very distinct interval. By further growth a straight