Standard methods for the examination of water and sewage

by American Public Health Association. Laboratory Section; American Chemical Society; Association of Official Agricultural Chemists

[121]. Woodman, A. G., and Norton, J. F. Air, water, and food, 4th ed., pp. 72–8, John Wiley & Sons, New York, 1914;

[121a]. pp. 85–7;

[121b]. pp. 90–1, 216, and 231;

[121c]. pp. 106–8.

MICROSCOPICAL EXAMINATION.

The microscopical examination of water consists of the enumeration of the kinds of microscopic organisms (Plankton), and an estimation of their quantity.

It may serve any one or more of the following purposes:

(1) To explain the presence of objectionable odors and tastes. (2) To indicate the progress of the self purification of streams. (3) To indicate the presence of sewage contamination. (4) To explain the chemical analysis. (5) To identify the source of a water. (6) To aid in the study of the food of fish, shellfish, and other aquatic organisms.

The term “Microscopic Organisms” shall include all organisms microscopic or barely visible to the naked eye, with the exception of the bacteria. It includes the diatomaceae, chlorophyceae, cyanophyceae, fungi, protozoa, rotifera, crustacea, bryophyta, and spongidae found in water.

Fragments of organic matter, silt, mineral matter, zoöglea, etc., shall be considered as amorphous matter. The recording of amorphous matter usually serves no useful purpose and shall not be considered a part of the standard method.