THE MICROTOMIST'S VADE-MECUM

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CHAPTER XV.
BACTERIA-STAINING.
THE processes that it is necessary to employ for the          uiian
staining of Schizomycetes are of a somewhat special nature,       a
so that it appears desirable to give here a special account of  Foil
them.                                                           1eakt
164. Bacteria-Staining (Blanchard's method').-A film of      V, El
bacteria from an infusion is fixed by treating it with strong   fiTls
osmic acid on a slide. It is then covered, the osmic acid      recomm
drawn off, and a drop of violet of methylanilin run in under   s11ti
the cover. In half an hour's time the preparation may be        Ft Ill
completed by running in glycerin to which is added a small      edoUS
quantity of the violet in order that the stain may not be       11118N'
extracted from the organisms. Or concentrated solution of      en1111
sulphate of calcium may be used instead of glycerin. The         1R
bacteria are stained of a fine violet, the ground- substance   1t ul,
remaining colourless.                                           6ic
Other anilin stains may be used,. but methyl-violet appears  hilinla
to be the most durable.                                         'i d
Heematoxylin may     be used.   In this case the film    of  :rer
bacteria should be stained in it for twenty-four hours (after   R5a10
fixing with osmic acid) ; the iridescence which is then formed  inak'l
and spoils the clearness of the preparation is removed by       0i i
repeated washing, and the membrane is mounted in glycerin
or chloride of calcium.
. I ' Rev. Inter. Sci.,' iii (1879), p. 245. 'Journ. Roy. Mic. Soc.,' ii
(1879), p. 463.

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