patient, whose blood shewed a considerable increase of the eosinophils,
that the contents of the pemphigus bulla consisted almost entirely of
eosinophil cells. Neusser now produced a non-specific inflammatory bulla
in the skin by a vesicant, and found that the cellular elements in it
were exclusively the polynuclear neutrophil concerned in all ordinary
inflammations.

Exactly analogous conditions, occurring spontaneously, have been
demonstrated by Leredde and Perrin in the so-called Duehring's disease.
The bullae which appear in this dermatosis contain, so long as their
contents are clear, chiefly polynuclear eosinophil cells. In a later
stage, as is usually the case, bacteria effect an entrance into the
bullae, which now become filled with neutrophils.

According to modern views on suppuration, the experiment of Neusser and
the observation of Leredde and Perrin can only be explained by the
hypothesis, that the eosinophil and neutrophil cells, as we have
already several times mentioned, are of different chemiotactic
irritability. Hence the eosinophil cells only emigrate to those parts
where a specific stimulating substance is present. From this point of
view experiments and clinical observations known up to the present on
eosinophilia may be readily explained. Neusser's experiment for instance
may be explained in the following way. In the pemphigus bullae a
substance is present that chemiotactically attracts the eosinophils.
Hence the cells normally contained in the blood emigrate into them, and
produce the picture of an eosinophilous suppuration. Should the disease
assume from the first a localised distribution only, the essential
feature of the process is excluded. =A totally different appearance,
however, is produced= when the disease has attacked large areas. =Under
these circumstances large amounts of the specific active agent reach the
blood-stream by absorption and diffusion. Here it exercises a strong
chemiotactic influence on the physiological storage depot of the
eosinophils, the bone-marrow; leading to an increase of the eosinophils
of the blood to a greater or less degree. The bone-marrow, according to
general biological laws, is by the increased emigration now further
stimulated to a fresh production, and during a protracted illness can
hence keep up the eosinophilia.=

In this way other clinical observations may be explained. Gollasch has
found that the sputum of asthmatic patients contains, in addition