Observations on the Diseases of Seamen

by Sir Gilbert Blane

The facts above mentioned brought into my mind what is related of the plague at Smyrna and other places, that it disappears at the hottest part of the year. It is also curious and important to remark, that the true pestilence never has been heard of between the tropics. It is not easy to assign the cause of this effect of heat upon infection, as every thing relating to this subject is very obscure. We can conceive it to be owing to the greater degree of airiness which the heat of the climate makes necessary, or to the use of fewer woollen clothes. There may be something in the state of the body, particularly in the pores of the skin, which disposes them less to imbibe or produce the poisonous effluvia, or, when imbibed, it may more readily be thrown out by perspiration with the other acrimony of the blood; or more probably, as has been hinted above, the virulent matter is of such a degree of volatility as to be readily dissipated in a certain degree of heat[56].

There is a fact, which, though seemingly of a contrary tendency, yet is in reality in proof of the same opinion. It is, that these same diseases disappear in circumstances of great cold. When England was last visited by the plague, it disappeared in winter; and the same is observed at Moscow and other places. In this case the infectious matter is rendered inert, but not extinct, and the return of heat sets it afloat in the atmosphere, so as to expose it to human respiration. Dr. Guthrie informs us, that infection is entangled and fixed by the cold of winter on the doors and walls of the houses of the Russian peasants, and that upon the return of the warm season it is set loose by the thaw, and then becoming active, produces diseases.

With regard to the West Indies, the precautions that have been laid down are chiefly necessary when a ship newly arrives in the climate; for it is during the first three or four months that sickness is apt to prevail.

This does not depend upon any thing peculiar to the climate; for I have known ships arrive without being visited with any sickness. It seems to be owing, for the most part, to that flock of infection and disease imported from Europe exerting its effects, and when this has spent itself, the men remain in good health, unless exposed to the land air or other accidents; for the air at sea in those climates, as well as every where else, is extremely pure and wholesome, and there is no where that seamen are more healthy or comfortable.

SECT. III.
Of the Foul Air generated in a Ship.

I mean here to distinguish the unwholesome vapour produced by the contents of the ship from the infection produced by the effluvia of men’s persons, which was treated of in the last section.

The means of preventing this foul air from being generated are, cleanliness, dryness, and ventilation.

All parts of a ship may, if neglected, become dirty, and emit an offensive vapour; but the parts under water consisting of the orlop and hold, are more particularly so from the materials they contain, and from the want of free access to the fresh air; accordingly, there is always more or less stench in those parts, even in the best-regulated ships.

It was mentioned in the first part of this work, that an opinion was entertained by some that no foul air was productive of fevers but such as proceeds from the living human body. I alledged that this was otherwise, at least in hot climates; and some proofs of this opinion were adduced, particularly from the French prizes. Though the neglect of personal cleanliness is the principal source of disease, yet cleanliness of every kind, and purity of the air in every respect, is to be anxiously studied.

With regard to general cleanliness, it is hardly necessary to mention sweeping, washing, and scrubbing of the decks; for the natural propensity of the English[57] nation to neatness seldom allows any neglect of these. Lord Howe, to whose virtues as a man, and abilities as an officer, his country is so much indebted, gave it in general orders to wash the upper decks every day, the lower decks twice a week, and the orlop once a week at least. He also ordered that, every washing, smoking, mustering, and review of clothes, or any other means taken for the health of the ship, should be marked in the logbook, and the reason to be assigned there if omitted at the stated times. These rules are a good specimen of the order that ought to prevail in every branch of public duty; for it is well known to every experienced officer that it is a methodical proceeding of this kind which can alone render service either easy or effective.