ar
leucocytosis, as Ehrlich had already mentioned in his first
communication. The diminution is often considerable, often indeed
absolute.

A few diseases shew, besides the neutrophil leucocytosis, an increase of
the eosinophils as well, as we shall describe in detail in the next
section.

Polynuclear neutrophil leucocytosis--leucocytosis [Greek: kat'
exochen]--may be divided into several groups =according to their clinical
occurrence=. We distinguish:

A. =physiological leucocytosis=,

which appears in health as an expression of changes in the physiological
state. To this group belongs the leucocytosis of digestion, the
leucocytosis from bodily exertion (Schumburg and Zuntz) or from cold
baths, and further the leucocytosis of pregnancy.

B. =pathological leucocytosis=.

1. The increase of polynuclear cells occurring in infectious processes,
often called inflammatory, after the principle "_a potiori fit
denominatio_." The majority of febrile infectious diseases, pneumonia,
erysipelas, diphtheria, septic conditions of the most varied aetiology,
parotitis, acute articular rheumatism, etc. are accompanied by a
leucocytosis of greater or less extent. In this connection uncomplicated
typhoid fever and measles occupy a peculiar position. In them the
absolute number of white blood corpuscles is diminished, and chiefly at
the expense of the polynuclear neutrophil cells.

For the details we have quoted, and for the course and variations of
leucocytosis in infectious diseases we refer to the thorough monograph
of Tuerk. Of Tuerk's observations we will mention only that in the final
stage of the process of leucocytosis, which occurs at the time of the
crisis in diseases which run their course critically, mononuclear
neutrophil cells and stimulation forms as well often make their
appearance in the blood. In still later stages, in which the blood has
once more a nearly normal composition, a moderate increase of the
eosinophils--gradually waxing and again waning--is very frequently found
(Zappert and others). Stienon, who has likewise devoted special
researches to the occurrence of leucocytosis in infectious diseases,
shews this point very well in his curves.

2. =Toxic leucocytosis= occurring in intoxications with the so-called
blood poisons. This important group has not yet received adequate
treatment in the literature. In general the majority of blood poisons,
potassium chlorate, the derivatives of phenyl hydrazin, py