Elementary biology; an introduction to Elementary biology; an introduction to the science of life elementarybiolog00grue Year: 1924 INSECTS AS SPREADERS OF DISEASE 399 If' The habits of the fly are such that we cannot afford to be associated with this animal in any way whatever. The female lays her eggs in horse manure; but where there is no horse 1 8 15 22 29 6 13 20 27 3 10 17 24 31. 7 14 21 28 6 12 19 26 JUNE JULY AUGUST SEPTEMBER . OCTOBER Fig. :o5. Flies and intestinal diseases In New York City a careful study was made (1907-1908) to find the relation between the prevalence of flies a
Elementary biology; an introduction to Elementary biology; an introduction to the science of life elementarybiolog00grue Year: 1924 INSECTS AS SPREADERS OF DISEASE 399 If' The habits of the fly are such that we cannot afford to be associated with this animal in any way whatever. The female lays her eggs in horse manure; but where there is no horse 1 8 15 22 29 6 13 20 27 3 10 17 24 31. 7 14 21 28 6 12 19 26 JUNE JULY AUGUST SEPTEMBER . OCTOBER Fig. :o5. Flies and intestinal diseases In New York City a careful study was made (1907-1908) to find the relation between the prevalence of flies and the amount of typhoid fever. The height of the dotted line cor- responds to the number of flies caught in traps, week by week, from the beginning of June to the end of October. The solid line corresponds to the number of people who died from intestinal diseases during the same period in the same districts of the city. Typhoid is most frequent where and when flies are most abundant, and there is a direct connection between the insects and the distribution of the disease manure, she will use cow, sheep, pig, or chicken manure, or decaying fruit, fish, meat, or vegetables, — ordinary garbage, for example, — or any mass of decaying organic matter. The adult flv will visit, for feeding, not only such materials as have been mentioned, but all kinds of perfectly good food that may be
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