THE MICROTOMIST'S VADE-MECUM
I quote the first from Foster and Balfour's ' Elements of         t
Embryology' (French edition), not knowing where it was first
published.
91. Alcoholic Humatoxylin (Eleinenberg's first formulal).      _
a. Make a saturated solution of crystallised chloride of calcium
in 70 per cent. alcohol, and add alum to saturation.
b. Make a saturated solution of alum in 70 per cent.
alcohol and add 1 volume of the former (a) to eight of the
latter (b).                                                      that
c. To the mixture thus obtained add a few       drops of a      fab1
barely alkaline saturated solution of humatoxylin.       (This   06t
should be a saturated solution in absolute alcohol.)             thenonS1
This method was afterwards simplified by the omission of        yepOf
the alum from (b), and now runs as follows:                       ColOUrtS
92. Alcoholic Hmmatoxylin (Kleinenberg's second formula2).       Sl
-" Prepare a saturated solution of calcium chloride in 70 per     SOlu0n.
cent. alcohol with the addition of a little alum; after having     pYdfor
filtered, mix a volume of this with from 6 to 8 volumes of 70      ayenIl
per cent. alcohol. At the time of using the liquid pour into the air
it as many drops of a concentrated solution of humatoxylin        solution
in absolute alcohol as are sufficient to give the required colour    h
to the preparation of greater or less intensity, according to      bas
desire."                                                           thcka
At Naples, according to Mayer ('Mitth.,' ii, 1881, p. 13),      yP
the solution of calcium chloride is used saturated with alum.       Foil
Mayer further states that the object of the chloride of          vry St
calcium is explained by Kleinenberg to be the setting up of        nadhil
diffusion currents between the alcohol in the tissues and the        I
external staining medium, so as to facilitate the penetration
of the latter.
Mayer points out that by the reaction of alum and calcium
chloride there is formed a precipitate of sulphate of lime, and
I 'Ellments d'Ernbryologie,' de Foster et Balfour, 1877, p. 296.  nuo
2 'Quart. Journ. Mic. Sci.,' lxxiv (1879), p. 208.


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