Collecting Water Samples Light Microscopy

Collecting Water Samples for Light Microscopy.

Collecting Water Samples for Light Microscopy

While a bottle or jar may be used for collecting microscopic material from shallow pools and streams, it is not the most desirable device because it permits the collection of too much water along with the organisms. We therefore make a collecting net which permits the water to drain a\vay while the aquatic life is concentrated in the bottle at the apex of the net.

To the end of a broom handle three or four feet long attach a ring made of heavy galvanized iron wire about eight inches in diameter. This may be fastened by drilling a hole in the end of the wood and inserting the twisted ends of the loop, or it may be wired to the handle with thin copper wire. To this loop fasten a conical net of muslin about twelve inches long. The apex of this cone should be hemmed to prevent fraying. Into the hole left in the apex insert a small wicle-mouth bottle of about four ounces capacity, holding it with stout rubber bands. This permits removal of the bottle when it is filled. To use the net simply drag it through the water, skimming the bottom, scraping the stems and leaves of aquatic plants, scraping the trunks of submerged trees, piling or anything else that may be in the water. When the small bottle is filled with the concentrated collection it may be emptied into a larger bottle containing a quantity of water. In this way samples may be taken from a number of places, thereby increasing the number of species of animal and vegetable life collected.

One drop of this water examined under the microscope will reveal an enormous quantity of living things. These need air to support life and should not be confined in a tightly closed jar or bottle. The forms of life are tiny but there are thousands of them and they use up air at a surprising rate, so leave a generous amount of air in the container in which you carry home your collection. These specimens must also be fed if they are to be kept alive for future study. This is not difficult to do as any aquarium affords an excellent breeding place. The aquarium must be kept for just this purpose and should not contain fish. Let the student look up the construction of a balanced aquarium and build one along the lines suggested. Introduced into this aquarium the microscopic animals will live and flourish and be always at hand when wanted for study.

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