. A civic biology : presented in problems. Biology; Sanitation. 200 THE ECONOMIC IMPORTANCE OF ANIMALS $15,000,000 a year has been derived during the last decade from such sources. Hundreds of boats and thousands of men are engaged in dredg- ing for oysters. Three of the most important of our oyster grounds are Long Island Sound, Narragansett Bay, and Chesapeake Bay. Sometimes oysters are artificially " fattened " by placing them on beds near the mouths of fresh-water streams. Too often these streams are the bearers of much sewage* and the oyster, which lives on microscopic organisms
. A civic biology : presented in problems. Biology; Sanitation. 200 THE ECONOMIC IMPORTANCE OF ANIMALS $15,000,000 a year has been derived during the last decade from such sources. Hundreds of boats and thousands of men are engaged in dredg- ing for oysters. Three of the most important of our oyster grounds are Long Island Sound, Narragansett Bay, and Chesapeake Bay. Sometimes oysters are artificially " fattened " by placing them on beds near the mouths of fresh-water streams. Too often these streams are the bearers of much sewage* and the oyster, which lives on microscopic organisms, takes in a number of bac- teria with other food. Thus a person might be- come infected with the typhoid bacillus by eating raw oysters. State and city supervision of the oyster industry makes this possibility very much less than it was a few years ago, as careful bacterio- logical analysis of the surrounding water is con- stantly made by com- petent experts. Clams. - - Other bivalve mollusks used for food arc clams and scallops. Two species of the former are known to New Yorkers, on? as the " round," an- other as the " long ' or "soft-shelled" clams. The former (Venus mercenaria) was called by the Indians "quahog," and is still so called in the Eastern states. The blue area of its shell was used by the Indians to make wampum, or money. The quahog is now extensively used as food. The " long ' clam (Mija arenariu) is considered better eating by the inhabitants of Massachusetts and Rhode Island. This clam was highly prized as food by the Indians. The clam industries of. This diagram shows ho\v cases of intestinal disease (typhoid and diarrhea) have been traced to oysters from a locality where they were " fat- tened ' in water contaminated with sewage. (Loaned by American Musmim of Natural History.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration a
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