The micro-organisms of the human mouth : The local and general diseases which are caused by them.

  • Miller, Willoughby Dayton, 1854-1907.
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: The micro-organisms of the human mouth : The local and general diseases which are caused by them. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    ceed in exactly the same manner, except that the cultures must be kept at a temperature just below that at which the gelatine used liquefies. Instead of the ordinary glass plates, Petri'sche Schalen may often be used to great advantage. Dilution Cultures. We may illustrate the principle of dilution cultures in the fol- lowing manner: Suppose we have a handful of seeds of various kinds which are invisible to the naked eye, and we are given the task to separate the seeds, or at least to obtain pure cultures of Fio. 16. Second Dilution op a Gelatine-Culture from the White Deposit on the Teeth. a, very small; b, medium-sized ; e, very large, round colonies; d, irregular colony. The different sizes represent different rapidities of growth. Culture three days old. them. We may accomplish the task in the following manner: We go out to the field and cast the seed broadcast upon the ground which has been prepared for the sowing, wait till they spring up and ripen, then gather the different plants which are produced into separate heaps. In this way we obtain pure cul- tures of all the different plants represented in the original hand- ful of invisible seeds. In applying this principle to the pure cultivation of micro- organisms we proceed as follows: Having melted three tubes