This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...lakes, ponds, and reservoirs contains more Protozoa than either rain water or ground water, and standing water is, as a rule, more crowded with them than running water. The organisms that float passively in the water without seeking the shore or bottom constitute a group known as plankton. An examination of the waters ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...lakes, ponds, and reservoirs contains more Protozoa than either rain water or ground water, and standing water is, as a rule, more crowded with them than running water. The organisms that float passively in the water without seeking the shore or bottom constitute a group known as plankton. An examination of the waters of a typical river (the Illinois River) revealed 528 different species of plankton. These were mostly plants (algae), Protozoa, wheel animalcules, and Entomostraca (see p. 144). One hundred and eighty-five of the 528 species recorded were Protozoa, and every cubic meter of water contained an average of 112,000,000 protozoan individuals (Kofoid). The numbers of Protozoa in different kinds of water are indicated by the following statistics (Whipple). A flowing brook contained 10 per cubic centimeter. A reservoir contained 97 per cubic centimeter. A pond contained 666 per cubic centimeter. The trouble caused by the Protozoa is chiefly due to their odor and taste. Besides this, Protozoa may cause temporary intestinal disorders in people not accustomed to a certain kind of water. On the other hand, some Protozoa undoubtedly aid in purifying water of Bacteria; for example, the flagellate Bodo greatly reduces the number of typhoid fever germs by using them for food. Some of the common species of Protozoa that cause trouble are Uroglena (Fig. 137, A), which has a fishy or oily odor; Synura, with an odor of ripe cucumbers and a bitter and spicy taste; and Bursaria, with an odor resembling that of a salt marsh. The water in reservoirs may be purified by the use of copper sulphate (blue vitriol). About one part of copper sulphate to from five to twenty million parts of water should be used. This should be placed in a bag and dragged through the water beh...
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