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...
MITOSIS-LIKE ACTIVITY IN BACILLUS SP. A
The organism used was isolated from the soil and grown on glucose agar. In size and fermentation it corresponds in a measure with Bacillus mesentericus. Only the R type was used since the staining reaction of the S type was not satisfactory. A twelveto thirteen-hour culture was used as the parent culture. Since stains of the growing culture were to be made at different time intervals, as many transfers were made as time intervals, thus giving a separate culture for each staining period. After the transfers were made cells were removed from the parent culture and stained (figs. 1 and 2). Some of these cells stained throughout. Others had more heavily stained structures within the cytoplasmic region. The arrangement of these structures, within limits, constituted a type of configuration. The cells from the two-hour culture (fig. 3) may or may not stain. Some of the figures resemble in a measure those characteristic of the parent cells while others may contain one or even two spherical bodies. Some of these cells stain rather uniformly throughout, while others give a motley effect. A more deeply stained spherical body may appear in cells otherwise uniformly stained. Where two spherical bodies appear they may be equal or unequal in size and occur separately or partially united. The wall region of some cells remains unstained. The stoning pic-
Affordable housing in London
Introduction. The Housing Situation in London. Housing, Land Use Planning, and the Government of London, a Brief History. Land Use Regulations. Positive Local Authority Powers in London. Sources of Affordable Housing: the Rented Sectors. Grants to Assist Access to Affordable Housing. Conclusions. Bibliography.