re specially
suited for demonstration preparations of lymphatic leukaemia.

4. Eosin-methylene blue mixtures, for example Chenzinsky's fluid:

Concentrated watery methylene blue solution 40 c.c.
1/2% eosin solution in 70% alcohol 20 c.c.
Aqua dest. 40 c.c.

This fluid is fairly stable, but must always be filtered before use. It
only requires a fixation of the specimen for five minutes in absolute
alcohol. The staining takes 6-24 hours (in air-tight watch-glasses) at
blood temperature. The nuclei and the mast cell granulations stain deep
blue, malaria plasmodia light sky blue, red corpuscles and eosinophil
granules a fine red.

This solution is particularly suited for the study of the nuclei, the
baso and eosinophil granulations, and it is used by preference for
anaemic blood, and also for lymphatic leukaemia.

5. 10 c.c. of a 1 per cent. watery eosin solution, with 8 c.c. methylal,
and 10 c.c. of a saturated watery solution of methylene blue are mixed,
and used at once, see page 41. Time of staining 1, at most 2 minutes.
The staining is characteristic only in preparations very carefully fixed
by heat. The mast cell granulations are stained pure blue, the
eosinophil red, the neutrophil in mixed colour.

6. Jenner's stain consists of a solution in methyl alcohol of the
precipitate formed by adding eosine to methylene blue.

Grubler's water soluble eosine, yellow 1.25% } a.a. watery
" medicinal, methylene blue 1% } solutions.

Precipitate allowed to stand 24 hours, and then dried at 55 deg.. It is then
made up to 1/2% in methyl alcohol (Merck). The stain may be obtained
from R. Kanthack, 18, Berners Street, London, ready for use. It is
exceedingly sensitive to acids and alkalis. Fixation is effected by
heat. Time of staining 1-4 minutes.

Before we pass to the histology of the blood, two important methods may
be described, for which the dried blood preparation is employed
directly, without previous fixation: 1. the recognition of glycogen in
the blood; 2. the microscopic test of the distribution of the alkali of
the blood.

1. _Recognition of glycogen in blood._

This may be effected in two ways. The original procedure consisted in
putting the preparation into a drop of thick cleared iodine-indiarubber
solution under the microscope, as had been already recommended by
Ehrlich for the recognition of glycogen.

The follo