. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. FLOWERLESS PLANTS 175 and leave their remains in our water supply. Much of the un- pleasant taste and odor of drinking water comes from this cause. Pond Scum (Spirog7jra).âThis alga is well known to every boy or girl who has ever seen a small pond or sluggish stream. It grows as a slimy mass of green threads or fila- ments. Frequent- ly it is so plentiful as almost to cover the surface of the water, buoyed up by little bubbles of a gas which seems to arise from the body of the plant. If we
. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. FLOWERLESS PLANTS 175 and leave their remains in our water supply. Much of the un- pleasant taste and odor of drinking water comes from this cause. Pond Scum (Spirog7jra).âThis alga is well known to every boy or girl who has ever seen a small pond or sluggish stream. It grows as a slimy mass of green threads or fila- ments. Frequent- ly it is so plentiful as almost to cover the surface of the water, buoyed up by little bubbles of a gas which seems to arise from the body of the plant. If we place some of the Spiro- gyra in a deep dish of water, taking care to put the dish in the sun, the green plant will be found to give off enough gas to cause the plants to float near the surface. If we collect some of this gas, we can easily prove that it is oxygen. The person who sees a pond with a covering of slimy pond scum, knowing this fact, should no longer feel that the pond is a menace to health, un- less, indeed, it is a place where mosquitoes live and breed. n ^ 1 I^^^^^^^^^^H a â p.:. A B A, jar of water containing pond scum; B, same jar after an hour in the Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Hunter, George William, 1873-1948. New York, American book company
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