This enumeration, therefore, under that view, comprises, in addition to marshes, whether fresh or salt, all the cases where water is present in such a manner as to act upon vegetables; and the chief are the following. [p104]
It is shown, and by facts, that the rushy swamps of high moorlands, however small the extent, do produce this disease; and we must not here forget to name what, however, belongs to the preceding chapter, woods and coppices, little suspected in England, yet shown to be the cause of fevers in Wales, and also in Sussex; very probably, every where else. It is also shown that meadows and moist pastures, whether in flat lands or on elevations, generate fevers; and very particularly, should they have been affected by inundation or unusual moisture, and if that should be followed by heat. And while it is also specifically shown how, in all cases, it is the produce of the drains or ditches required in meadow lands, it is distinctly proved that, even without these, malaria is produced, or that it is generated by the meadow or moist pasture itself.
It is also shown that this poison is produced by rivers, by all flat rivers at least, or those of which the progress is slow and through meadow lands; while this is pointed out as one of the causes, especially, which is not suspected or not believed in England. And here we can add a fact to our author’s statement, which is decisive: this is the case of the barracks at Morne Bruce, in Dominica, situated on a steep and rocky hill, perfectly dry, and free from all other causes of suspicion, while eternally subject to the most severe fevers. And the cause is, a mountain stream, about 300 yards below this building, in the valley, always covered by a mist in the evenings, and ascertained, by direct experience, to be the very cause of the diseases in question.
Our author also notices canals, mill-ponds, ornamental waters, and all other pools and ponds, even to so small a dimension as those formed in gravel-pits; pointing out those, in particular, as common causes of fever about London, and apparently much inclined to pass a very severe judgment on the canal in St. James’s Park, and also on the pond in St. James’s Square, while apparently restrained by his prudential reasons, which appear to us sufficiently misplaced, or, as we should fairly call them, somewhat absurd. But as we must not affront a writer whose papers we have admitted, we shall say no more on this matter. In noticing drains, he also speaks of moats and modern fortifications; attempting to show that the fevers so common in the sieges of ancient castles were produced by their moats, and noticing the familiar fact of the frequency of fevers in fortified towns. Lakes also are pointed out as situations generating this poison: and it is here especially noticed that if, in those and other cases, malaria is produced by the vegetable growth and decomposition, [p105] so is it the consequence of the exposure of the mud of such receptacles of water; a cause which is again treated of at greater length in the subsequent chapter.
This chapter relates to what the author calls obscure and disputed cases. We shall pass over these, which, as not implying precautionary measures, are of the least interest, and commence by noticing the case of vegetable putrefaction. It is attempted to show, that the vegetable need not be living to produce malaria, but that, even if utterly decomposed, its elements, acting on water, can generate this poison. Among the cases under this head, are flax and hemp ponds, common sewers and drains, dunghills, and tide harbours; and the evidences under each are sufficient to make good the assertion. But the most important of all, in our view at least, is bilge-water: since our author has pretty clearly shown that all the fevers of ships (excepting, of course, a few casual instances of contagion) arise from this cause, and that if ships were kept clean, fever or sickness would be nearly unknown at sea. This we do indeed conceive one of the most important points in the work before us; and if the author has referred to Sir Henry Baynton, as a stranger, we can quote him, as a friend, that warrants for all that is here asserted, and for far more; since his collection of facts on this subject is most important, and we think him almost culpable in not having long ago given them to the public. If the Leviathan was always the healthiest ship in the navy; if she even left the West Indies, after a long anchorage and service, with a crew of 500 men, and not one sick, it is a case in the navy which never occurred before, nor since, and which arose entirely from the knowledge of this able and careful officer respecting the subject that we are discussing.
A sixth chapter explains, under the head of revolutions in the production of malaria, a variety of circumstances not easily admitting of abridgment. The chief of these are, the effects produced by drainages, and reversely, those which arise from inundations or other incidental causes affecting the state of the soil. But the most important view which it contains is that which relates to the effect of embankment in rivers, and to the geological changes produced by the distribution of alluvia. As, however, we cannot well state this in a small space, we shall pass to the chapter on the Propagation of Malaria.
This is the largest, and, as it strikes us, the most interesting of the whole; while the author has made it the depository of a variety of remarks and recommendations on this [p106] subject, very particularly as it relates to the army. If he is correct,—and we see no reason to doubt it, from the nature of the statements,—the ignorance of this subject, even among the medical department of the army, has been most extraordinary and most unaccountable; while if Walcheren is proof enough of this, the writer before us has pointed out facts enough to show that it was not a solitary case, while evidently restrained by fear of some sort—we are almost inclined to call it cowardice—from telling all that he might have told. And we do think it wrong to retain or suppress that which is important to the public safety, under a fear that the feelings of individuals may be hurt; since the business of a writer is with justice and utility, and the security or welfare of thousands is of infinitely greater moment than the comforts of a few, and those also culpable.
Under this head, propagation, the author describes how this poison is conveyed by the winds, while the facts add much to the number and variety of the precautionary measures. And here also we find a speculation of no small curiosity, respecting the East wind, attempting to prove that wherever this is insalubrious or pernicious, it arises from its being the vehicle of malaria; while attempting also to prove that this substance can be conveyed from Holland to the coasts of England in that wind. We shall not pretend to give an opinion on this subject; and since the author himself has noticed it in the paper printed in our present number, we shall suffer our readers to form their own judgments respecting it.
One also of the most curious facts mentioned in this chapter, is the singular limitation of malaria; and we must admit that the instance quoted as to the Chatham road is so remarkable as to be almost incredible; though, as we find that all the people agree in it, we cannot pretend to say it is not a fact. Indeed the facts of this nature, so familiar at Rome, are fully as inexplicable; so that all we can conclude is, that we are ignorant of the philosophy of this subject: no very great cause of surprise, unless it were proved that we could explain every thing else which belongs to meteorology.
In the eighth chapter we have an explanation of the effects of climate and seasons in the production of malaria; and while we need not analyse the facts which it contains, we may introduce in lieu of this, the explanations which its statements afford as to that recent increase of the diseases of malaria which we noticed at the commencement of this article. The last few years have been distinguished for an [p107] uncommon prevalence of East winds, and to such a degree indeed, that we can find no meteorological records at all to be compared with the history of these years. And while the history of the intermittent and remittent, in London at least, from the time of Morton and Sydenham downwards, shows that all its periods of such diseases have been periods of East winds, it is not difficult to see how it acts as to both classes of marsh fever. To London, in particular, it is the best conductor, propagating the malaria from all the moist lands to the eastward. To the East coast, if our author’s theory is valid, it brings the malaria from Holland; and, moreover, as it forms our hottest summers, it causes our own climate to approximate more to the southern ones, and thus enables our lands to produce a greater quantity of malaria than in ordinary summers.