Iron bacteria / by David Ellis, with illustrations and 5 plates.

  • David Ellis
Date:
[1919]
Catalogue details

Licence: In copyright

Credit: Iron bacteria / by David Ellis, with illustrations and 5 plates. Source: Wellcome Collection.

    41/250 (page 15)
    will be discussed later, the writer is of opinion that the more troublesome Gallionella and Spirophyllum are both pleomorphic phases in the life history of Leptothrix ochracea. If such be the case the com- paratively harmless Leptothrix must be regarded with suspicion equalled to that bestowed on Gallionella and Spirophyllum. Therefore, it is important to the engineer to note that Leptothrix forms resting cells in the form of conidia. As shown above these minute oval structures are formed in countless num- bers in ferruginous waters, and constitute the “ germs ” out of which new individuals arise. The question of the location of the resting cells of the iron-bacteria has often been discussed, and on a few occasions has formed the subject of an official inquiry. It may be stated that the conidia constitute, so far as is known at present, the only form of resting cells of Leptothrix. I am quite convinced that the thread itself does not as a whole become a restino- cell, the so-called arthro- spore of de Bary. This phenomenon does occur occasionally in the lower bacteria, but there is no evidence of the existence of a similar mode of repro- duction in the case of Leptothrix. In all cases the threads multiply by fragmentation and then die out, but the conidia which they liberate in countless num- bers persist and, under favourable circumstances, ! germinate to form new threads. I have not followed t the germination of the conidium of Leptothrix, but I have done so in the case of the conidia of Spiro- I phyllum which are identical in practically every