MACERATIONS AND CORROSIONS

i Borme's formula 1).-Ten per cent. solution of sodium chloride,
5 volumes; absolute alcohol, 1 volume.
For vibratile epithelium, Ranvier finds the mixture inferior
t to one third alcohol.
451. Chromic Acid.-Generally employed of a strength of
about 0-02 per cent. Specially useful for nerve tissues and
smooth muscle. Twenty-four hours' maceration will suffice
[ for nerve tissue. About 10 c.c. of the solution should be
[ taken for a cube of 5 mm. of the tissue (Ranvier).
452. Bichromate of Potash.-0'2 per cent.
453. iiller's Solution and Saliva.-See below, No. 462.
453a. Permanganate of Potash-Has an action similar to
I that of osmic acid. Is recommended, either alone, or com-
I bined with alum, as the best dissociating agent for the fibres
of the cornea (Rollett, ' Stricker's Handbuch,' p. 1108).
454. Osmic Acid.-0-1 per cent., for from a few minutes to a
J fortnight (cortex of cerebrum, Rindfleisch). May be followed
I by maceration in glycerin.
455. Osmic and Acetic Acid (the Hertwigs' formula 2):
0-05 per cent. osmic acid   .    .    . 1 part.
0-2    ,,     acetic acid   .    .
Meduste are to be treated with this mixture for two or three
i minutes, according to size, and then washed in repeated
o changes of 01 per cent. acetic acid, until all traces of free
osmic acid are removed. They then remain for a day in 0-1
per cent. acetic acid, are washed in water, stained in Beale's
carmine (in order to prevent the osmium from over-blackening
and to assist the maceration), and are preserved in glycerin.
For Actinie,3 the osmic acid is taken weaker, 0-04 per cent.;
I Moleschott's 'Untersuchungen zur Naturlehre,' xi, pp. 99-107.
Ranvier, ' Trait6,' p. 242.
2 'Das Nervensystein u. die Sinnesorgane der Medusen,' Leipzig, 1878,
p. 4.
3 ' Jen. Zeitschr.,' xiii (1879), p. 457. ' Journ. Roy. Mic. Soc.,' iii (1880),
p. 441, and (N.S.), iii (1883), p. 732.

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