Fermentation organisms : a laboratory handbook / by Alb. Klöcker; translated from the german by G. E. Allan and J. H. Millar.

Date:
1903
Catalogue details

Licence: In copyright

Credit: Fermentation organisms : a laboratory handbook / by Alb. Klöcker; translated from the german by G. E. Allan and J. H. Millar. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    35/458 (page 11)
    irrowtli, and from this he then infers that tiie flasks wliich ushow development each contain a pure culture. But’this method affords no security, and Hansen there- fore, in 1880-81, worked out his first method, which has been referred to above. He made the important observa- tion that the yeast cells, after they have been well shaken up in the flask containini^ nutrient li(piid, sink to the bottom, and form there distinct and well-separated spots of yeast. Examination showed, as was to be expected, that those dasks, in which only a single 3^^east spot had developed, contained a pure culture. This observation was a consider- able step forward. With this method Hansen combined cell-counting by means of a cover glass divided into scjuares. This rendered it possible to sow a single cell in each flask, and an exact method of preparing pure cultures in large (quantities was thus obtained. At the same time Robert Koch q^ublished his investi- gations on qDathogenic bacteria, and, like Hansen, he felt the need of a satisfactory q)ure culture method for the j)re- qoaration of mass cultures. Nutrient gelatine was brought by him into extensive use in bacteriology (XXI. I). His first method (1881) for pure culture consisted in dilution in nutrient gelatine. Before the viscous gelatine had com- pletely set, it was stroked with the point of an inoculation needle which had previously been in contact with the growth from which the re(]uired q:>ure culture was to be qwepared. The last streak made in this way may contain isolated colonies. The method was, as one can see, a verv imperfect one, and Koch soon introduced another, viz., that of plate cultures (1883) (XXI. 2). In this method the germs are distributed in li(|uefied gelatine, and are, by this means, more thoroughly disqiersed. Like Hansen, Koch also observed the single sq)ot; but the last-named method is not so sure as that of Hansen, in which the cells can be