Hydrogen chloride gas for effecting staining of internal structures in Escherichia coli.
The cells were smeared in water or water which had stood over about 10 mg. of magnesium powder per ml. for 30 minutes or longer. After the smear was dry and whitish in appearance it was held over a beaker of hot water (60-65° C.) until it was translucent or becoming translucent and exposed immediately to hydrogen chloride (gas) for a few seconds. After drying, it was covered with a 0.1% aqueous solution of neutral red for 5-8 minutes. The excess stain was washed from the slide with water and, while wet, placed in a saturated aqueous solution of mercuric nitrate for 5-15 seconds. The smear was rinsed in water and allowed to dry. When dry the slide was placed on a 50° C. warm plate and covered with a thin film of a 5% aqueous solution of nigrosin adjusted to a pH of about 3. The film dried quickly and upon cooling was ready for study. The stained material in the cells varied in shape and location with the moisture content of the smear and the time of exposure to hydrogen chloride. In the area of the smear d...
Crystal violet as a nuclear stain for gaffkya tetragena and other bacteria.
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.
General expression for the density effect for the ionization loss of charged particles
The equations for the density-effect correction $\ensuremath{\delta}(X)$ for the ionization loss as given in a previous paper have been extended to the case where $\ensuremath{\delta}({X}_{0})\ensuremath{\equiv}{\ensuremath{\delta}}_{0}g0$. Here ${X}_{0}$ is the lower limit of the range ${X}_{0}lXl{X}_{1}$, where a particularly simple expression for $\ensuremath{\delta}(X)$ applies; $X={log}_{10}(\frac{p}{{m}_{0}c})$, where $p$ is the momentum and ${m}_{0}$ is the mass of the incident particle. The case ${\ensuremath{\delta}}_{0}g0$ applies directly to the calculation of $\ensuremath{\delta}(X)$ for conductors (metals).