The principles of bacteriology : a practical manual for students and physicians / by A.C. Abbott.

Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: The principles of bacteriology : a practical manual for students and physicians / by A.C. Abbott. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    is tliat based upon constant characteristics which are -seen to appear in the course of their development under special conditions—certain of them possessing the power of forming spores, while from others this peculiarity is absent. As yet but little is known of the life history of the spiral forms. Efforts toward their cultivation under artificial conditions have thus far been unsuccessful. Morphologically, they are thread- or rod-like bodies which are twisted into the form of spirals. In some of them the turns of the spiral are long, in others quite short. They are motile, and multiply apparently by the simple process of fission.^ The micrococci develop by simple fission. When development is in progress a single cell will be seen to elongate slightly in one of its diameters. Over the center of the long axis thus formed will appear a'slight indentation in the outer envelope of the cell; this indentation will increase in extent until there exist eventually two individuals which are distinctly spheri- cal, as was the parent from which they sprang, or they will remain together for a time as diplococci. The sur- faces now in juxtaposition are flattened against one another, and not infrequently a fine, pale dividing line may be seen between the two cells. A similar division in the other direction will now result in the formation of a group of forms as tetrads. This, in short, is the method of multiplication of the micrococci. In the fiirmation of the staphylococci such division occurs irregularly in all directions, resulting in the pro- duction of the clusters in which these organs are eoni- 1 Dividing into two transversely.