wet from the chloroform is then mounted in canada
balsam. In such preparations the morphological elements have preserved
their shape completely. The plasma shews a distinct red colour, whilst
the red corpuscles have taken up no colour. The protoplasm of the white
corpuscles is red, the nuclei appear as spaces, because unstained
(=negative nuclear staining=). The disintegrated corpuscles and the fibrin
which is produced, shew an intense red stain. These stains are
peculiarly instructive, and shew many details which are not visible in
other methods. The study of these preparations is really of the highest
value, since they allow the products of manipulation of the dry
preparation and every error of production to stand out in the most
reliable manner, and so render possible a kind of automatic control. The
scientific value of this method lies in the fact that it throws light on
the distribution of the alkali in the individual elements of the blood.
It appears that free alkali reacting on iodine-eosine is not present in
the nuclei; these must therefore have a neutral or an acid reaction. On
the contrary the protoplasm of the leucocytes is always alkaline, and
the largest amount of alkali is held by the protoplasm of the
lymphocytes. We call particular attention, in this connection, to the
strong alkalinity of the blood platelets.

FOOTNOTES:

[4] Kloenne and Mueller, Berlin, supply these after Ehrlich's directions.

[5] Baden Anilin and Soda manufactory, Kalle and Co.

[6] At M. Heidenhain's instigation, the Anilin-dye Company of Berlin
have prepared the three dyes in the crystalline form.

[7] It may also be used for the recognition of glycogen in secretions.
For instance, gonorrhoeal pus always shews a considerable glycogen
reaction of the pus cells. It is found, moreover, in cells which
originate from tumours, whether these be present in exudations, or
obtained by scraping.

B. NORMAL AND PATHOLOGICAL HISTOLOGY OF THE BLOOD.

In satisfactorily prepared dry specimens =the red blood corpuscles= keep
their natural size and shape, and their biconcavity is plainly seen.
They present a distinct round homogeneous form, of about 7.5 mu in
diameter. They are most intensely coloured in a broad peripheral layer,
and most faintly in the centre corresponding to their depression. With
all stains mentioned above the stroma is quite uncoloured, and the
haemoglobin exclusively attracts the stain, so that for a practised