An introduction to practical bacteriology for physicians, chemists, and students / by W. Migula ; translated by M. Campbell and edited by H. J. Campbell.

  • Migula, W. (Walter), 1863-1938.
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: An introduction to practical bacteriology for physicians, chemists, and students / by W. Migula ; translated by M. Campbell and edited by H. J. Campbell. Source: Wellcome Collection.

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    tial, if tlie preparation is to be of any use, to refraiu fi'om heating it in Order to dry it more quickly. If lefb alone, the bacteria do not practically alter their shape at all during the process of drying; bot they do not adhere so firmly to the cover-glass that they cannot be easily washed oflf with water, and hence it is necessary to “fix” the layer which contains theui. The simplesb way to do this is to pass the cover-glass, with the side on which the bacteria are uppermost, three times through the öame of a Bunsen burner, at the Same rate as the pendulum of a middle-sized regu- lator Swings. This fixing requires great care; if the cover-glass is not sufEciently heated, the bacteria do not subse- quently stain so readily, and also are apt to become detached from its surface; if, on the other hand, it is too much heated, they almost entirely lose their power of absorbing the stain. The safest plan is to take up the cover-glass by its edges between the forefinger and thumb, and to pass it quickly through a low flame of the Bunsen burner, until it becomes unpleasantly warm. Particles of gelatine and agar-agar must never be transferred with the bacteriuin material on to the cover-glass, for, although they dry well, these uutrieut niedia do not become securely fixed, and hence are apt to become detached later, especially when warm stain- ing Solutions are added, when as a rule they carry the