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any portions of the Colony. Copies of a pamphlet entitled "Advice concerning Mosquitoes and Malaria", in both English and Chinese, have also been freely distributed to householders and every effort has been made to induce them to take part in the work of mosquito destruction. The amount spent on nullah training for the years 1909, 1910 and 1911 were respectively $7,737, $30,628 and $24,650, while the total length of trained nullahs and channels built since the commencement of anti-malarial work in the Colony is 47,023 ft., or 8.9 miles; the total cost of this work has been $246,204.
It has been suggested that the decrease in the incidence of the disease during 1911 may to some extent have been accounted for by the nature of the rainfall during the year. It will be seen that in two months of the Summer, viz., May and August, over 52 inches of rain fell, the heavy rainstorms in these months would scour out the many mosquito breeding pools on the hillsides and in this way diminish the number of mosquitoes.
There can be no question that varying climatic conditions from year to year must influence the output of Anophelines and consequently the incidence of Malaria—Ronald Ross has shown that this incidence bears a direct mathematical relationship to the number of Anophelines in any district—but that the explanation is not so simple as would appear from the above is demonstrated by the following Table. This shows the rainfall during each month of the year, the monthly admissions for Malaria to the Tung Wah Hospital and the total deaths each month from this disease, and it will be seen that a low Malaria rate was general throughout the year and that the figures were uninfluenced by the heavy rainstorms of May and August.
January.
February.
March.