s alike have
taken up a similar point of view. Among anatomical papers we may refer
to those of Gulland, according to whom all varieties of leucocytes are
but different stages of development of one and the same element. He
distinguishes hyaline, acidophil and basophil cells, and derives all
from the lymphocytes. Arnold advocates similar views, though in a
negative form. He says that a distinction between so-called lymphocytes
and the leucocytes with polymorphous nuclei, on the grounds of the form
of the cell and nature of the nucleus, is not possible at the present
time. Neither is a classification based on the granules admissible,
since the same granules occur in different cells, and different
granules in the same cell. The work of Gulland and Arnold takes into
consideration the differential staining of the granules in various ways.
In spite of their facts we disagree with their conclusions; and we shall
therefore have to analyse them in the special description of the
granulated cells and granules.

Recently (since 1889) Uskoff has in particular published experimental
work in this province of haematology. This has led him to see in the
white blood corpuscles the developmental series of one kind of cell, and
to distinguish in it, three stages: (1) "young cells," which correspond
to our lymphocytes; (2) "ripe cells" (globules murs), large cells with
fairly large and irregularly shaped nucleus, which are therefore our
large mononuclear and transitional forms; (3) "old cells" (globules
vieux), which represent our polynuclear cells. The eosinophil cells are
completely excluded from this classification. Amongst clinicians A.
Fraenkel has recently gone in the same direction, and on the grounds of
his experience in acute leukaemias has supported the view of Uskoff, that
the lymphocytes are to be regarded as young cells, and early stages of
the other leucocytes. But few authors (for instance C. S. Engel,
Ribbert) have raised a protest to this mixing of all cell forms of the
blood, and have held to the old classification of Ehrlich. But as it is
emphatically taught in numerous medical works that all these cells are
closely related, the grounds for sharply separating the lymphocytes from
the bone-marrow group may here be shortly summarised, and stress laid on
the great importance which this apparently purely theoretical question
has for clinical observation. We shall come to most important
conclusions upon this point when we cons