Abstract
A method is given to stain the nucleus of Gaffkya tetragena and other bacteria. Only water solutions of crystal violet, mercuric chloride, and nigrosin are used. While the application of heat (50°C. for 20 seconds) is not absolutely necessary, it facilitates the decolorizing process. Some of the nuclei of cells from old cultures were found in various stages of division. The nucleus of a mature cell divides, and each daughter nucleus undergoes a second division usually in a plane at right angles to that of the first division. The nuclear division indicates cell development in units of four cells each. The method was found reliable for demonstrating the nucleus at various periods and stages of growth.