Thus miasmatic fevers are two hundred times more frequent north of the equator than south of it, notwithstanding that there are extensive regions in South America and Australia covered with standing water and exposed to a burning sun. To this may be added that attacks of fever are much less severe in the southern hemisphere. Only light fevers prevail in the great lagoons of Corrientes; how much more dangerous are the fevers of the Pontine marshes, which are, nevertheless, very far from the equator! A European can live with much greater security against the contingency of fevers on the banks of the Parana, in South America, than on the banks of the Garigliano, in Italy.
There has been no lack of attempts and theories to explain these differences in localities that seem otherwise generally to stand under the same physical relations, but none of them have been successful. Yet it appears to be established that the greatest difficulties in the way of Europeans becoming acclimated in places where their business leads them to settle are due to the presence of swamp miasms. We know that a variety of conditions must combine to produce such miasms, and we know also that man is able to contend against them. It is possible for man to open a campaign against Nature wherever he goes, and to introduce conditions more favorable to his becoming acclimated. But he has so far not been able to bring a whole country immediately into a healthy condition; only time seems to be competent to bring such a work to completion, and, waiting its course, numerous victims have to be offered up.
The cultivation of the eucalyptus, a tree of remarkably quick growth, appears to be one of the most effective means now available for improving the condition of unhealthy localities. There are frequently tracts of limited extent in the most sickly regions where the process of acclimatization is relatively easy and secure. Such points should always be chosen by new settlers. The contrary has generally been the case. The beauty and fertility of the alluviums at the mouths of rivers, with the conveniences they offer to trade, have generally been tempting enough to determine the location of the settlement, regardless of its qualities with reference to health; and towns have been planted in such places in consideration of the apparent value of the money-investment, but in complete forgetfulness of the immense capital in human lives they are destined to swallow.—Translated for the Popular Science Monthly from Das Ausland.
