He says: "Ces globules granuleux actifs presentaient des mouvements de progression et des changements de forme caracteristiques et rapides; cependant je n'ai pas vu ces globules presenter de pseudopodes effiles; de plus, leurs contours restaient presque toujours assez nettement arretes. Ces particularites correspondent exactement a la description, qu'a donnee depuis longtemps Max Schultze des mouvements des cellules granuleuses du sang normal." Examination of dry specimens from the same case shewed, as Jolly expressly mentioned, that the blood contained, as leukaemic blood always does, polynuclear and mononuclear eosinophil cells. In contrast then with all earlier observations, Jolly has demonstrated an active spontaneous movement of the mononuclear eosinophil cells. The amoeboid movement of the mononuclear cells is so seldom seen, not because they lack this function, but obviously from defects in the methods of investigation, which as is manifest are rather rough and wholly unsuited for delicate biological processes. There are many instances in the literature of the failures of this method, even in the case of cells with undisputed mobility. Thus Rieder failed to observe any contractility in the majority of polynuclear leucocytes in a case of malignant lymphoma, whereas according to all other observations they possess this property without exception. We think then we must draw the conclusion that the feeble mobility of the mononuclear cells, both eosinophilous and polynuclear, is only apparent, and is owing to the gross method of investigation. In reality they doubtless have mobility sufficient for emigration. A further, but much less weighty objection to the view that myelogenic leukaemia is an active leucocytosis is, that pus artificially produced in leukaemic patients has nearly always the histological constitution of normal pus. But from our previous detailed remarks we should only expect a myelaemic constitution of the pus, if the specific morbid agent of leukaemia were present in a concentrated form at the place of inflammation. Just as we saw in pemphigus, Neusser's eosinophilous suppuration occurred only in the specific pemphigus bullae, but not in the foci of suppuration that were artificially produced. We know that the myelocytes are in no way positively influenced by the chemiotactic stimuli of ordinary infectious agents. On the contrary, it clearly follows from the above-mentioned observations on the transformation of leukaemic blood under the influence of infectious diseases, that the common bacterial poisons act in a negatively chemiotactic sense, both on the eosinophil and on the neutrophil mononuclear cells. Under these circumstances we should indeed expect that artificially produced suppuration in leukaemic patients would have, not a myelaemic, but a polynuclear neutrophil character.