Morphological Elements Present in the Tubercle Bacillus Cultures.

Abstract

When tubercle bacillus cultures are ground with water and centrifuged, the largest part of the bacteria is easily sedimented, but a turbid suspension remains which cannot be cleared, even with prolonged centrifugalization. With the Sharpless super centrifuge a nearly clear fluid is obtained, and the filtration through infusoria earth or paper pulp gives a perfectly clear filtrate. After filtering the thoroughly centrifuged suspension a viscous material remains on the filter, which material can be easily distributed in water. Examination of this revealed the following characteristics: Stained according to the method of Ziehl Neelsen it takes the counter stain, very few acid-fast bacteria being present in it. More thorough examination of the preparations (the best pictures are obtained in slides not decolorized after the carbolfuchsin staining) shows that the non-acid fast material consists of bacteria and small granules. These forms, both the bacteria and the granules, even when the preparations are not decolorized, are stained neither with fuchsin nor with methylene blue, but can be seen as a negative picture between small amounts of slightly red or blue material. In the dark field numerous small granules are visible between larger forms. We obtained the best information concerning the form and size of the element in smears with argyrol. These non-colorable forms were found in large amounts in the broth cultures of 5 strains and in the culture of a freshly cultivated strain on egg medium. The described forms are present in the cultures, and are not produced through the grinding of the bacteria. This is shown when a small piece of culture is spread with gentle rubbing on a slide.