ALCOHOLIC CARMINE

a distilled water. To 1 volume of the solution add 2 volumes
k absolute alcohol, and filter.
Stains more slowly than the last formula, oxalic acid
i carmine (No. 80). Overstains may be washed out with alco-
k holic solution of borax or oxalic acid. Is particularly appli-
4 cable to cartilage, and to bone that has been decalcified by
chromic acid.
A41   81. Alcoholic Borax-carmine (Grenacher'sformulal).-It is
evident that the procedure for employing borax-carmine must
be modified if it be wished to stain large pieces of tissue or
entire organs before cutting sections. In this case, take a
concentrated solution of carmine in borax solution (2 to 3 per
cent. carmine to 4 per cent. borax); dilute it with about an
equal volume of 70 per cent. alcohol, allow it to stand some
time, and filter. Acetic acid must not be added. Leave the
preparations in the stain until they are thoroughly penetrated,
and then bring them (without first washing out) into alcohol
acidulated with 4 to 6 drops of hydrochloric acid to each
1 100 c.c. of alcohol. They are left in this until they are
t )  thoroughly penetrated, and may then be washed or hardened
i in neutral alcohol.
82. Alcoholic Borax-carmine (Bourne's formula2).-The
4   directions given by Bourne are somewhat different from those
given by Grenacher. A mixture of carmine and borax solution is
fin  allowed to stand for two or three days and occasionally stirred;
I the greater part of the carmine will dissolve. To the solution
di is added an equal bulk of 70 per cent. of alcohol; the mixture
1   is allowed to stand for a week and then is filtered. If on
keeping more- carmine is deposited it must be refiltered. The
l   tissues may remain in the stain for one, two, or three days,
according to size.   They should remain in the acidulated
a alcohol till they acquire " a bright transparent look " (three to
six hours).
1 'Arch. Mik. Anat.,' xvi (1879), p. 466, et seq.
2 'Quart. Journ. Mic. Sci.,' lxxxvii (1882), p. 335.

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