In the second series to which the cases of Israel and Leyden, as well as the recently published one of J. Epstein from Neusser's wards, belong, the blood shews, besides the usual anæmic changes, other anomalies which are peculiar partly to pernicious anæmia, partly to myelogenic leukæmia. In Epstein's case of metastatic carcinoma of the bone-marrow, there was found a considerable anæmia, with numerous nucleated red blood corpuscles both of the normo- and megaloblastic type; their nuclei presented the strangest shapes, due not merely to typical nuclear division, but also to nuclear degeneration. The white blood corpuscles were much increased, their proportion to the red was 1/25 to 1/40; the increase concerned in the main the large mononuclear forms, which bore for the most part neutrophil granulation, and were therefore to be called myelocytes. In all the specimens, only two eosinophil cells were found[18].
The explanation of a blood picture of this kind, apart from the purely anæmic changes, is by no means easy, as Epstein rightly observes. The appearance of myelocytes is most readily explained by a direct stimulation of the remaining bone-marrow by the surrounding masses of tumour. In this, the mechanical factor is less concerned than the chemical metabolic products of the tumour masses; which at first act on the adjacent tissue in specially strong concentration, and also in a negatively chemiotactic manner on the wandering cells. This view receives support from the careful work of Reinbach on the behaviour of the leucocytes in malignant tumours. Out of 40 cases examined, in only one, of lymphosarcoma complicated with tuberculosis, were myelocytes found in the blood, amounting to about 0.5-1.0% of the white blood corpuscles. The autopsy shewed isolated yellowish white foci of growth in the bone-marrow, reaching the size of a sixpenny piece. Bearing in mind that in none of the other 39 cases were myelocytes demonstrated, one does not hesitate to explain their presence in the blood in this single case by the metastases in the bone-marrow. The small extent of the latter is likewise the cause of the small percentage of the myelocytes.
In explaining the presence of the megaloblasts in the blood of Epstein's patient we must keep before us what we have said elsewhere on this kind of cell. They are not present in the normal bone-marrow; they arise on the contrary, according to our view, when a specific morbid agent acts upon the bone-marrow, as we must assume is the case in the pernicious forms of anæmia. In the cases of anæmia from tumours, in which we find megaloblasts in large numbers in the blood, we must likewise assume that chemical stimuli proceed from the tumours, leading to the formation of megaloblasts in the bone-marrow.