the whole tract, and in no place more so than the bare sandy beach near the high-water mark_. The coloured people alone ever venture to inhabit it; and when they see strangers tarrying on the shore after nightfall, they never fail to warn them of their danger. The same remark holds good in regard to the greater part of the leeward coasts of Martinique, _and the leeward alluvial bases and recesses[24] of hills, in whatever port of the torrid zone they may be placed_, with the exception, probably of the immediate sites of towns, where the pavements prevent the rain-water being absorbed into the soil, and hold it up to speedy evaporation." Now, conceive a populous crowded town placed in this situation, and you have exactly what Gibraltar and the other towns of Spain and North America, liable to yellow fever, must become in such seasons as I have above described, only, that as they grow more populous and crowded, the danger must be greater, and its visitations more frequent, unless the internal health police be made to keep pace in improvement, with the increasing population. [Footnote 24: The leeward niches and recesses of hills, however dry and rocky, become in these seasons of drought, absolute dens of malaria, this will be found proven in my reports made especially of the islands of Dominique and Trinidad, which may be seen at the Army Medical Board Office.] Now in the name of injured commerce--of the deluded people of England--of medical science--of truth and humanity--what occasion can their be to institute an expensive quarantine against such a state of things as this, which can only be mitigated by domestic health police; or why conjure up the unreal phantom of an imported plague, to delude the unhappy sufferers, as much in regard to the true nature of the disease, as to the measures best calculated for their own preservation; when it must be evident that the pestilence has sprung from amidst themselves, and that had it been an external contagion in any degree, the ordinary quarantine, as in case of the plague, would certainly have kept it off; but the question of the contagion of yellow fever, so important to commerce and humanity; and which, like the Cholera, has more than once been used to alarm the coasts of England, demands yet further investigation.