III. ENDEMIC DISEASES.
Agua.—Of all diseases usually classed under the head Endemic, there is no one more truly so, or of which the habitudes have been so accurately ascertained, as ague. Although ignorant of the nature of the actual agent that produces this disease, we are well acquainted with the principal circumstances amid which it originates, insomuch that we can always predicate, with considerable certainty, upon examining any locality, whether or not the inhabitants there residing are subject to this affection. It is hardly necessary to state, that the particular situations liable to ague, are those which contain marshes, or are, at least, low and flat, containing much stagnant water in pools or ditches, &c.
The topographical account of the Landsend, in the former part of this paper, which characterises the whole district as hilly, dry, and almost devoid of any thing like marshy lands or stagnant waters, will lead any one to predicate its comparative immunity from ague: and this prediction is proved to be correct by the actual history of the district. In the Penzance Dispensary Reports, only three cases are recorded in a period of seventeen years, and among upwards of 8800 patients. During my residence, only one case occurred at the Dispensary; and this is the only one witnessed or heard of by me during that period. In the eleven years subsequent to my residence, not a single case was entered on the Dispensary books. The oldest practitioner in the district had never known a single case to occur in the town of Penzance, in a practice of fifty years. The case witnessed by me, occurred in the person of a
