Thus lymphatic leukæmia affords a striking proof that the lymphocytes are cells of a peculiar kind, and which are quite independent of the polynuclear cells. It is therefore exceedingly surprising that Fränkel, after accurately examining and analysing eight cases of acute lymphatic leukæmia, believes he has found in them imperative reasons for the assumption that the lymphocytes are transformed to polynuclear cells. This can only be explained by the confusion which Uskoff's doctrine of "young cells" has brought about.
We define lymphocytosis as an increase of the lymphocytes of the blood; Fränkel like Uskoff regards it as the emigration of the young forms of the white blood corpuscles into the blood. He concludes logically from the diminution of the polynuclear cells in this form of disease "that the conditions of the transformation of the young forms have undergone a disturbance." But if one assumes that the lymphocytes are young forms, and the polynuclears their older stages, it is much nearer to the facts to speak, not of a disturbance in lymphatic leukæmia, but of an absolute hinderance to the ripening process. It is easy to conceive any particular stimulus or injury bringing about an acceleration of the normal process, that is, a premature old age, but it is equally difficult to represent clearly to oneself conditions which retard or completely prevent the normal ageing of the elements. The discovery of such conditions would be really epoch-making, both for general biology, and for therapeutics. The only escape from this dilemma would be the assumption of a very premature death of the lymphocytes, for which however not the smallest evidence is to be found, even in Fränkel's monograph. Fränkel distinguishes the acute from the chronic forms of leukæmia by the fact, "that in the former the newly formed elements emigrate from their places of formation into the blood-stream with extraordinary rapidity. Hence there is not time for further local metamorphosis. In chronic leukæmia the emigration takes place very probably much more slowly." This distinction is contradicted by the facts; for =there are chronic forms of lymphatic leukæmia whose microscopic picture is identical with that of acute leukæmia=. And hence the starting-point of all Fränkel's deductions is rendered insecure.