| Abstract: | The authors have been studying the bacterial diseases of the brood for a fairly long time. American and European foul brood has been studied with the highest attention. Cultures of Bacillus larvae (White, 1906) were examined both in freshly isolated strains and in collection strains of this micro-organism. In cases of foul brood, the pathological material was found to contain not only the typical rods of B. larvae but also immobile spiral forms which are usually referred to in literature as fragments or developmental forms of B. larvae. These spiral forms were found to constitute spindle-shaped formations in the culture of B. larvae; the multiplication of these spindles depends on the presence of the rods of B. larvae and their development and reproduction can be observed on wet gelatine agar in a Petri dish turned upside down under a normal microscope (10 X 10 magnification). In the combined liquid medium, used in the experiments, these formations disintegrate into immobile spirals; if re-cultivated on a solid medium they re-assume their spindle shape with transverse meridian arrangement (in different amounts). Staining for proving the presence of nucleic acids does not eliminate the possibility of these formations being separate micro-organisms which cannot be stained by current staining methods but can be represented by the contrast method according to Burri, or by silvering according to Klein. The authors succeeded to separate these micro-organisms, but without the rods of B. larvae the colonies of these formations are feeble. |
