Annual report of the Public Health Department / Zanzibar Protectorate.

  • Zanzibar. Public Health Department.
Date:
[1920]
Catalogue details

Licence: Public Domain Mark

Credit: Annual report of the Public Health Department / Zanzibar Protectorate. Source: Wellcome Collection.

    21/52 (page 21)
    is required to perform the work, and the risk of corrosion of the boiler plates through excessive use of the material is not so great. The latter point is most important—no more of the sodium carbonate than is necessary to attain the requisite degree of softening should be used It is advisable not to attempt to get the maximum soften¬ ing obtainable, as that entails the risk of a certain quantity of the carbonate remaining in the water, where it may do more or less serious damage to the boiler. From the above experimental details it is indicated that 15 parts of sodium carbonate per 100,000 of the water would be a safe amount to use; that is with the hot process. This amount is equivalent to 15 pounds of the anhvdrous salt per 10,000 gallons of water, or 25 pounds of “washing soda” (Na2C03. 10 H20) per 10.000 gallons. A. C. BARNES, Analyst. Zanzibar, June 28th, 1920. Report No. 107/B. REPORT. On Bacteriological Examination. Samples of Water from Zanzibar In considering the Bacteriological findings, notice has to be taken of the fact that as no ice was placed in the box after leaving Zanzibar and as the ice had all disappeared on receipt in the Laboratory, presumably the samples were at the temperature of their surroundings for about 36 hours. This would permit of a rapid multiplication of anv Bacteria present in the water. /. Bu-Bu-Bu Spring. (Sample No. 76.) Col onies on Bile Salt Media Plates (Presumtive Intestinal) at 37°C uncountable per c.c. in 48 hours (non-Lactose fermenters). B. coli less than 20 per litre. Streptococci less than 20 per litre. B. enteritidis 100—1,000 per litre. Remarks.—This sample does not ‘diow signs of recent contamin¬ ation. No B. coli were found in the quantity available for examination. Streptococci were also absent from the quantity. It may be considered satisfactory.