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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    early formation of loops in the central portion of the chain is also seen. On the portion of the chain extending to the right a small angle may be noticed. The smaller bacillus is partly following the curves of the larger. Fig. 4 (170 minutes) shows increased growth and increased loop formation. The angle noticed on the right portion of the chain has now developed into a process and a loop is in the process of forma- tion. Fig. 5 (215 minutes) illustrates a further advance in loop formation and the development of parallel strands of bacilli. Both the right and the left ends of the chain are now seen to be producing secondary systems of loops. Fig. 6 (292 minutes) illustrates a more advanced condition of the central portion of the colony. Parallelism is well marked and numerous loops are seen. The rapidly developing secondary system of loops on the left end of the chain is well shown. Fig. 7 (x 100) is a photograph of the complete colony after seven hours’ growth. The primary system of loops is well shown in the middle and close to it on each side the secondary systems formed on the two ends of the chain. The two free ends are seen extending downwards. Above each of these is a less curved apparently freely projecting thread. These are in reality processes composed of parallel threads of bacilli produced in the same way as the process in Fig. 3. Fig. 8 illustrates the same colony after 23 hours’ cultivation. Growth has mainly occurred in the central portions of the colony resulting in the production of very numerous loops, and large numbers of strands of parallel threads of bacilli. Moreover the whole colony is not now on the same plane as increased growth in the centre has caused some strands to override others. In this series of photographs the formation of a complete colony is illustrated almost from the commencement of growth to the formation of a typical anthrax colony consisting of a raised centre of wavy strands surrounded by numerous loops and a few projecting threads. The development of such a colony has been followed on many occasions and complete division of the original chain has very seldom been noticed. Occasionally, however, this does occur after an acute angle has been formed. It may therefore be stated as a general rule that a superficial anthrax colony consists of a single twisted chain of bacilli. In the depth of the agar as on the surface a chain of closely approximated bacilli is first produced. As the chain grows it becomes irregularly curved; but owing to the resistance of the agar regular loops cannot be produced, and instead distorted loops, which may be