found 72% eosinophil cells in the blood in 1897. The
patient contracted a croupous pneumonia, and in the high
febrile period of the disease the number of eosinophils sank to
6-7%, and rose again after the termination of the pneumonia to
54%. After removal of the worm the number at once fell to 11%.
In the year 1898 the patient harboured but a very few
Ankylostomata; Charcot's crystals were no longer present in the
faeces; the number of the eosinophils amounted to 8%."

The question, what cells produce on their destruction actively
chemiotactic substances, is of very great importance; but cannot be
answered with the material at present available. The breaking up of
ordinary pus cells or lymphocytes does not appear to give rise to any
such substances; but there is much evidence that the decomposition
products of epithelial and epithelioid cells act chemiotactically. Thus
we can explain the frequent occurrence of eosinophilia in all kinds of
skin-diseases. Again, in all atrophic conditions of the gastric,
intestinal and bronchial mucous membrane there occurs a local
accumulation of eosinophil cells; further, this kind of cell is
increased in the neighbourhood of carcinoma. Additional support for this
view is seen in the fact that in bronchitis and asthma the less the
suppurative element of the secretion is developed, the more numerous are
the eosinophil cells. An observation of Jadassohn is worthy of mention
in this connection. He observed abundant eosinophil cells in foci of
lupus after injection of tuberculin. In these foci then, by the
destruction of the epithelioid cells brought about by the tuberculin,
substances must have been produced which act chemiotactically on the
eosinophil cells.

The specific substances are absorbed and reach the blood, and impart to
it also the chemiotactic power. =The direct cause then of most forms of
eosinophilia seems actually to lie in a destruction of tissue, and in
the products thus produced.=

On the other hand, it cannot be doubted that substances foreign to the
organism, circulating in the body, may act chemiotactically on the
eosinophil cells[32]. The observations quoted above, of the well-marked
eosinophilia in the different forms of Helminthiasis, may here be
specially mentioned. The action of the Helminthides was formerly
regarded as purely local, but the indications that they act also by the
production of poisonous substances continue to i