THE VIICROTOMIST'S VADE-MECUM

absolute alcohol before being brought into contact with oil of
cloves. If any moisture be left fading will soon commence and
the preparation be spoiled."                                         t
94. Alum Humatoxylin (Bochmer's formula).-Make (A)
a solution of pure humatoxylin (9j) in absolute alcohol (gss)
and (B) a solution of alumen deparatum (gr. ij) in water (3j).
Add 2 to 3 drops of A to a watch-glassful Of B. The sections      it
may remain in this for half a day to a day. They are then        diualt
treated as follows: absolute alcohol, solution of tartaric acid
in alcohol, absolute alcohol again, then benzine or turpentine,    eiti
and, finally, mounted in castor-oil.                                i t1
Other methods of treatment may be employed, provided            Pe:o'
that hydrated acids and resinous mounting media be avoided,
as both are detrimental to the colour of the stain. With          2d1 Pay
these precautions, however, the colour is permanent in glyce-     thlipl i
rin.2  Alcoholic extract of logwood only imperfectly surro-       the ed (
gates the alcoholic solution of haumatoxylin.
To stain objects that have been treated with chromic acid       h1rs. F
or its salts or with copper sulphate, &c., the solution A may
be diluted with pure water instead of the alum    solution; but    kg t]
the stain is more diffuse, and less strongly      held  by the     Athi
nuclei.                                                            (@t
95. Alum   Hmmatoxylin (Aqueous) (Duval's formulas).-            11
"One grain of concentrated solution of humatoxylin in alcohol       t
is added to about 800 grammes of water containing a little alum.   toI
There is thus obtained a solution that stains nuclei in a few      tketh
minutes."                                                           The
96. Hematoxylin Staining Solution (Aqueous) (Mitchell's         In the
formula4).
1 'Arch. Mik. Anat.,' iv (1868), p. 345.                         glp
2 Flemming finds the stain not permanent for more than a year either  Iopomu
in resinous media or in glycerin, that is to say, the stain loses in sharp-  deCop(
ness. 'Zellsubstanz, &c.,' p. 384.                                  slotn
S'Pr6cis Technique,' p. 220.                                      C00i
4'Proc. Acad. Nat. Sci. Philad.,' 1883. ' Journ. Roy. Mic. Soc.' (N.S.)*  +
iv, 1884, p. 311.

80