less degree however than in
the lymphocytes. No free glycogen is contained in the polynuclear cells
as a rule; nevertheless in certain diseases cells are always found which
give a marked iodine reaction. In this manner the appearance of cells
containing glycogen in diabetes was first proved. (Ehrlich,
Gabritschewsky, Livierato.) The iodine reaction in the white blood
corpuscles is also seen in severe contusions and fractures, in
pneumonias, in rapidly progressing phlegmata from streptococcus and
staphylococcus, after protracted narcosis (Goldberger and Weiss).

Ehrlich explains the appearance of glycogen as follows. The glycogen is
not present in the cell as such, but in the form of a compound, which
does not stain with iodine. This compound readily splits off glycogen,
which then gives the iodine reaction[12].

We cannot regard the perinuclear green granules, described by Neusser in
the polynuclear cells, as pre-existing. (See p. 42.)

The number of polynuclear leucocytes in the blood of the healthy adult
amounts to about 70-72%, of the total white corpuscles. (Einhorn.)[13]

5. =The eosinophil cells.= These are characterised by a coarse, round
granulation, staining deeply with acid dyes, and similar in other
respects to the polynuclear neutrophils. With faint staining, a thin
peripheral layer of the eosinophil granule is seen more deeply stained
than the interior. The nucleus as a rule is not so deeply stained as in
the polynuclear neutrophil, but otherwise in its general shape is
completely similar. Both forms have in common a considerable
contractility, which renders possible their emigration from the vessels,
and their appearance in exudations and in pus. The size of the
eosinophils frequently exceeds that of the neutrophils. Their number is
normally about 2-4% of the white cells.

6. The mast cells. These are present, though very sparingly, in every
normal blood; 0.5% is their maximum number in health.

Their intensely basophil granulation, of very irregular size and unequal
distribution, must specially be mentioned. The granulation possesses the
further peculiarity, in that with the majority of basic dyes it stains,
not in the pure colour of the dye, but metachromatically--most deeply
with thionin. As Dr Morgenroth found, the deviation from the colour of
the dye is still more marked with Kresyl-violet-R (Muelheim manufactory),
when the granules stain almost a pure brown.

The staining power of the nuclei