We have repeatedly demonstrated the position of the bacilli _in_ the cells, and explained them in diagrams, but in many preparations it is impossible to distinguish where the bacilli lie. The best method of definitely noting their position, which we know, appears to be the fixing of small nodes or small pieces of organs in Fleming’s or Müller’s fluid, with subsequent dehydration and hardening in alcohol; sometimes one gets excellent preparations by simply hardening in absolute alcohol. If the preparations are stained with fuchsin, and counter-stained with methyl blue, or still better, stained with gentian violet, decolourised by Gram’s method, and counter-stained with Bismarck brown or with Bismarck brown and eosin, one will never fail to see the bacilli lying definitely in the cells (_Plate VI, Fig. 8_). Even in such preparations there are many places where one cannot definitely distinguish the position of the bacilli; but as one always finds bacilli in the cells where the preparations are sufficiently clear, we may safely conclude that the bacilli lie everywhere _in_ the cells. In the connective tissue spaces one often sees bacilli in and round the nuclei of the connective tissue cells (_Plate X, Fig. 8_), and although the body of the cell is not visible, we may conclude that the bacilli lie in the cell body, and not free in the lymph spaces. We have found in many sections of the blood vessels in a testicle (_Plate X, Figs. 5_ and _6_), and in a liver (_Plate VIII, Fig. 6_, and _Plate IX, Fig. 1_), white blood corpuscles filled with bacilli, and in both cases only slight affection of the organ, and we also observed many bacilli in the endothelium of the vessels, as Touton and Unna have observed in skin nodules where we, we may remark in passing, have never seen them. From these observations we draw the conclusion that these two organs have been infected through the blood. As we do not know the manner and method of the primary infection of the organ, we must devote our attention to the search for discoveries like those described above, and to the localisation of the bacilli in general, in order to form an idea of the method of action of the bacilli.