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...
EFFECT OF FIXATIVES UPON DISTRIBUTION OF STAINABLE MATERIAL IN ESCHERICHIA COLI AS SHOWN BY HYDROGEN CHLORIDE METHOD OF STAINING
The importance of fixatives in the study of internal structures of bacteria is evidenced in papers by Murray (1953), Cassel and Hutchinson (1955), and by Robinow (1956b). The primary purpose of the use of these substances is to maintain, without distortion, the structure and material in the site in the cell where it functioned. In addition, the fixative may in some cases bring about changes in the substrate that are advantageous in staining the material. Few techniques or methods have been available to check the effectiveness of these substances. In this work it is proposed to use the hydrogen chloride method of staining (Chance, 1954) for this purpose. The method does not make use of a fixative prior to staining unless hydrogen chloride could be considered a fixative. This is not likely since in a modified staining procedure the stain can be used before the exposure of the cells to the gas. The distribution and shape of the stained material in cells of air dried smears was apparently a function of exposure to the gas.
Stability results for the solutions of some third and fourth order differential equations
SummaryThe paper investigates conditions under which solutions of the equations (1) and (2) of § 1.1 tend to zero as t → ∞.