"1. Excess of moisture, even on lands not evidently wet, is a cause of fogs and damps.
"2. Dampness serves as a medium for the conveyance of any decomposing matter that may be evolved, and adds to the injurious effects of such matters in the air:—in other words the excess of moisture may be said to increase or aggravate atmospheric impurities.
"3. The evaporation of the surplus moisture lowers the temperature, produces chills, and creates or aggravates the sudden and injurious changes or fluctuations by which health is injured."
In view of the foregoing opinions as to the cause of malaria, and of the evidence as to the effect of draining in removing the unhealthy condition in which those causes originate, it is not too much to say that,—in addition to the capital effect of draining on the productive capacity of the land,—the most beneficial sanitary results may be confidently expected from the extension of the practice, especially in such localities as are now unsafe, or at least undesirable for residence.
In proportion to the completeness and efficiency of the means for the removal of surplus water from the soil:—in proportion, that is, to the degree in which the improved tile drainage described in these pages is adopted,—will be the completeness of the removal of the causes of disease. So far as the drying of malarious lands is concerned, it is only necessary to construct drains in precisely the same manner as for agricultural improvement.
The removal of the waste of houses, and of other filth, will be considered in the next chapter.
CHAPTER XI. - HOUSE DRAINAGE AND TOWN SEWERAGE IN THEIR RELATIONS TO THE PUBLIC HEALTH.
The following is extracted from a report made by the General Board of Health to the British Parliament, concerning the administration of the Public Health Act and the Nuisances Removal and Diseases Prevention Acts from 1848 to 1854.