--%i     I

AQUEOUS INJECTION-MASSES                 279
Next, the spirit and the water are to be added very gradually,
the mixture being constantly shaken."
" The water " spoken of in the last sentence appears to mean
the remaining 3 ounces of water that were not mixed with
the glycerin at first.
Injected specimens should be preserved in acidulated
glycerin, otherwise the colour may fade.
436b. Neutral Glycerin (Turnbull's-Blue) (Bichardson's
formula l).-Ten grains of pure sulphate of iron are to be
dissolved in an ounce of glycerin, and 32 grains of ferrid-
cyanide of potassium in a small proportion of water and
then mixed with glycerin. Mix these two solutions gradually
and add the other ingredients as directed for the Prussian-
blue (last formula). Beale finds these proportions too large,
and prefers the following:
Ferridcyanide of potassium      .    .     10 grains.
Sulphate of iron     .     .    .    .      5
Water      .     .   .     .    .    .      1 ounce.
Glycerin (Price's)    .    .    .    .      2
Alcohol    .    .     .    .    .     .     1 drachm.
It is believed by some that Turnbull's-blue is less liable to
fade than the Prussian-blue. The colour is brighter.
1 Beale, ' How to Work, &c.,' 4th ed., p. 94.