us to a
highly artificial explanation of its production.

The morphological changes of leukaemic blood under the influence of
infectious diseases can only be explained from the standpoint of the
emigration theory. For if the white blood corpuscles were mechanically
carried out of the bone-marrow as a whole, it is incomprehensible that a
bacterial infection should alter this process to a polynuclear
leucocytosis. This change of character is easily explained on the other
hand, as we have above shewn more in detail, by the assumption that
ordinary bacterial poisons act positively chemiotactically only on the
polynuclear neutrophil cells, but negatively on the other forms.

=We explain the origin of leukaemic blood by the emigration into the blood
under the influence of the specific leukaemic agent, not only of the
formed polynuclear elements, but also of their mononuclear, eosinophil
and neutrophil early stages; and to classify myelogenic leukaemia with
the active leucocytoses.=

FOOTNOTES:

[25] Naturally an ordinary leucocytosis may be combined with a
lymphaemia. We have already mentioned elsewhere (see page 102) that in
the leucocytosis of digestion or of diseases of the intestine in
children, such a coincidence occurs.

[26] The so-called agony leucocytosis we do not regard as a true
leucocytosis, but only as the expression of a stoppage of the
circulation caused by that condition. This produces an accumulation of
the white corpuscles on the vessel walls, especially in the peripheral
parts of the body which are as a rule used for clinical investigation. A
leucocytosis is thus simulated.

[27] It is also of interest to notice the behaviour of the eosinophil
cells in the passive form of leucocytosis, lymphaemia. _A priori_ both
conditions could be combined. As C. S. Engel has established in the
congenital syphilis of children a simultaneous marked increase of
lymphocytes and eosinophil cells is found. The lymphocytosis in these
cases is probably due to the anatomical changes of the lymph glands, and
the eosinophilia to specific chemiotactic attraction.

[28] In his monograph on Bothriocephalus anaemia Schauman, with reference
to the behaviour of the eosinophil cells, states that he has found them
in but few cases of this disease.

[29] This view has lately received striking confirmation from the
interesting experiment of Baeumer, who produced on himself by means of
continued stimulation with _Urticaria ureus_