If there is any fact well established by satisfactory experience, it is that thorough and judicious draining will entirely remove the local source of the miasm which produces these diseases. The voluminous reports of various Committees of the English Parliament, appointed to investigate sanitary questions, are replete with information concerning experience throughout the whole country, bearing directly on this question. Dr. Whitley, in his report to the Board of Health, (in 1864,) of an extended tour of observation, says of one town that he examined:— "Mr. Nicholls, who has been forty years in practice here, and whom I was unable to see at the time of my visit, writes: Intermittent and remittent are greatly on the decline since the improved state of drainage of the town and surrounding district, and more particularly marked is this alteration, since the introduction of the water-works in the place. Although we have occasional outbreaks of intermittent and remittent, with neuralgic attacks, they yield more speedily to remedies, and are not attended by so much enlargement of the liver or spleen as formerly, and dysentery is of rare occurrence." Dr. Whitley sums up his case as follows:— "It would appear from the foregoing inquiry, that intermittent and remittent fevers, and their consequences, can no longer be regarded as seriously affecting the health of the population, in many of the districts, in which those diseases were formerly of a formidable character. Thus, in Norfolk, Lincolnshire, and Cambridgeshire, counties in which these diseases were both frequent and severe, all the evidence, except that furnished by the Peterborough Infirmary, and, in a somewhat less degree, in Spaulding, tends to show that they are at the present time, comparatively rare and mild in form." He mentions similar results from his investigations in other parts of the kingdom, and says:— "It may, therefore, be safely asserted as regards England generally, that:— "The diseases which have been made the subject of the present inquiry, have been steadily decreasing, both in frequency and severity, for several years, _and this decrease is attributed, in nearly every case, mainly to one cause,—improved land drainage;_" again: "The change of local circumstances, unanimously declared to be the most immediate in influencing the prevalence of malarious diseases, is land drainage;" and again: "Except in a few cases in which medical men believed that these affections began to decline previously to the improved drainage of the places mentioned, the decrease in all of the districts where extensive drainage has been carried out, was stated to have commenced about the same time, and was unhesitatingly attributed to that cause."