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Purification of Water by Infusoria

Published online by Cambridge University Press:  15 May 2009

C. S. Stokvis
Affiliation:
(From the Hygienic Institute, University of Amsterdam.)
N. H. Swellengrebel
Affiliation:
(From the Hygienic Institute, University of Amsterdam.)
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Infusoria have the same bactericidal power as flagellates. Emulsions containing Bacillus typhosus, Vibrio cholerae, V. Dunbar, V. El Tor, B. megatherium and Spirillum volutans, to which Colpoda cucullus is added, are soon cleared. Before the clearage the Colpodae multiply actively.

This bactericidal effect does not depend upon the production of toxic substances by the Infusoria. The fluid obtained from filtered cultures of the Infusoria exerts no bactericidal effect. Only living Colpodae are able to clear the emulsions.

Direct sunlight does not prevent the clearing of the emulsions by the Infusoria, but temperatures below 10°C. and above 30°C. and absence of oxygen (anaerobic culture) are unfavourable to their exerting a bactericidal effect.

The polluted water of the canals of Amsterdam slightly delayed the clearage of the emulsions; the sewage of starch factories and gas factories completely prevented this clearage.

Consequently under natural conditions Infusoria will only play a part in purifying river water (1) if the temperature is above 10° and under 30°C., (2) if the aquatic vegetation is rich enough to supply the necessary quantity of oxygen, (3) if the water is not highly polluted by adjoining factories.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1911

References

Hüntemüller, O.. (1905). Vernichtung der Bakterien im Wasser durch Protozoen. Archiv f. Hygiene, LIV. 89100, 1 pl.Google Scholar
Razetto, (1907). Ueber die hygienische Bedeutung der Protozoen im Wasser. Trans. Fourteenth International Congress for Hygiene and Demography in Berlin.Google Scholar
Stokvis, C. S.. (1909). Protozoen und Selbstreinigung. Archiv f. Hygiene, LXXI. 4659.Google Scholar