not be ascribed, which
therefore are only passively washed into the blood-stream by mechanical
forces ("~passive leucocytosis~").

The passive form of =leucocytosis= corresponds to the different kinds of
lymphaemia, including that of leukaemia. In the section on the lymphatic
glands, we have established this view in detail, and we have
particularly insisted that a suppuration, consisting of lymph cells,
does not occur.

In sharp contrast to this form there are for every specific kind of
active leucocytosis, analogous products of inflammation (pus,
exudations), composed of the same kind of cell.

We divide =active leucocytosis= into the following groups:

([alpha]) =polynuclear leucocytoses=:

1. =polynuclear neutrophil leucocytosis=,
2. =polynuclear eosinophil leucocytosis=;

([beta]) =mixed leucocytoses= in which the granulated mononuclear
elements take part; "=myelaemia=."

[alpha] 1. ~Polynuclear neutrophil leucocytosis~, is the most frequent
of all forms of active leucocytoses.

Virchow, the discoverer of leucocytosis, advocated the view, that it
resulted from an increased stimulation of the lymph glands. The
stimulation of the lymph glands consists in "that they are engaged in an
increased formation of cells, that their follicles enlarge, and after a
time contain many more cells than before." The swelling of the lymphatic
glands has as a consequence an increase of the lymph corpuscles in the
lymph, and through this an increase again of the colourless blood
corpuscles.

This standpoint had to be abandoned, when Ehrlich shewed that it is
chiefly the emigration of the polynuclear neutrophil cells, which brings
about leucocytosis. Exact figures on this point were first given by
Einhorn, who worked under Ehrlich, and were later generally confirmed.
Corresponding with the increase of neutrophil blood corpuscles alone,
there is always a relative decrease of lymphocytes, often to 2% and even
lower. It must here be borne in mind, that the percentage of the lymph
cells may be much diminished, without change in their absolute number.
It has however been conclusively demonstrated that occasionally in
polynuclear leucocytosis, the absolute number of the lymphocytes may
decrease. Einhorn had already described a case of this kind, and
recently Tuerk has for the first time established the fact by an
abundance of numerical estimations[25].

The eosinophil cells are as a rule diminished in ordinary polynucle