Physiology. — “On the genetic relation between lymphocytes and 
granulated leucocytes.’ By J. pr Haan and K. J. Frrtnea 
(Communicated by Prof. H. J. Hampureer). 
(Communicated at the meeting of Februari 22, 1920). 
There still exists a difference of opinion as regards the question 
to what extent the lymphocytes and granulated cells of the blood 
can be regarded as closely related cell kinds. It is agreed in general 
that the (neutrophile) granulated cells, when once formed, form a 
type by themselves for which there is no possibility of being trans- 
formed into other types of cells. Also with respect to the lympho- 
cytes the majority of researchers would have them regarded as 
a type sui generis that under no circumstances can pass over into 
granulated cells. The possibility of forming the latter would in that 
case be reserved only for a particular cell kind, which, it is true, 
bears very much the appearance of the lymphocytes, from which, 
however, they should differ fundamentally. These cells are distin- 
guished by the name of ‘“myeloblasts’. It is accepted that they occur 
normally only in the bone-marrow and only very exceptionally and 
in highly pathological states there can be formed in other places 
also, a kind of bone-marrow or myeloid tissue by “metaplasia” of 
cells present in the adventia of the vessels. This dualistic theory 
which was most zealously propagated by NAgri1 at present claims 
the greatest number of supporters; a lymphocyte never becomes a 
granulated cell; the latter can originate only from myeloblasts, by 
way of granulated large mononuclear myelocytes. 
Besides this the monistic theory still finds numerous supporters 
of which WerpeNrmicH and Maximow claim the first place. They lean 
on this that embryonically in any case there is no question of a 
principial division between the granulated and the non granulated 
cells, that in lower organisms transitions between these two cell 
kinds have been ascertained, and, furthermore, on the fact that, up 
to this, attempts to attribute specific characteristics to myeloblasts which 
would prineipially distinguish them from other cells of the mono- 
nuclear type, have failed. Contrary to this the dualists hold that 
such a principial difference is afforded amongst others by the oxydase 
