A complete handbook for the sanitary troops of the U S army and navy . liable toincrease rather than diminish the numljer of bacteria. Unless suchfilters are in perfect condition and frequently sterilized the bacteria WATER 341 grow into the substance of the filter, which finally becomes a culturemedium. The Darnall Siphon filter, from which very satisfactory resultshave been reported, combines precipitation xcith filtration, and pro-vides for maintaining the bacterial efficiency of the filtering mate-rials. The precipitant used is a combination of alum and sodaknown as hydroxide pozvder. The
A complete handbook for the sanitary troops of the U S army and navy . liable toincrease rather than diminish the numljer of bacteria. Unless suchfilters are in perfect condition and frequently sterilized the bacteria WATER 341 grow into the substance of the filter, which finally becomes a culturemedium. The Darnall Siphon filter, from which very satisfactory resultshave been reported, combines precipitation xcith filtration, and pro-vides for maintaining the bacterial efficiency of the filtering mate-rials. The precipitant used is a combination of alum and sodaknown as hydroxide pozvder. The apparatus arranged ready for use is shown in Fig. 222. Improvised filters intended only to clear muddy water are readilyprepared. The simplest form is that so common in tropical coun-tries, a small hole being dug in the sand near the edge of a stream,the water filtering through the intermediate sand or being caught onits way to the stream. Another simple method is to take two barrels of dififerent sizes,bore holes in the bottom of the larger and near the top of the. COARSE GRAVei. CHARCOAL SAND M0S3 Fig. 223,—Improvised Filter. Jil W /^ // ^U ^Zb=^ ^;i==S^^:^ri\ ?^£?= IS ^Sii Fig. & fe^^.^. ?COARSE GRAVEL-CHARCOAL y^., - ;/? -SANO 224 —Improvised 1 filter. smaller, place the smaller barrel inside the larger, fill in the inter-vening space with sand and sink both in the water (Fig. 223). Orthe larger barrel may be left intact, holes being bored in the bottomof the smaller, and the water being poured in on the sand betweenthe barrels (Fig. 224). Sand used for such purposes should alwaysbe washed and if possible sterilized before use, and this processshould be frequently repeated during use. Impure water may cause disease in several ways. Hard water orwater containing mineral salts often causes diarrhea, constipation, orindigestion in those unaccustomed to its use. Decomposing vegeta-ble or animal matter in water or the presence of living alg?e may alsocause diarrhea and indi
Size: 1421px × 1759px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectfirstaidinillnessand
