The last and most virulent Degree of Chilblains, which is not infrequent in the very coldest Countries, though very rare in the temperate ones, is, when the Inflammation degenerates into a Gangrene.

§ 463. These Tumours are owing to a Fulness and Obstruction of the Vessels of the Skin, which occurs from this Circumstance, that the Veins, which are more superficial than the Arteries, being proportionably more affected and straitened by the Cold, do not carry off all the Blood communicated to them by the Arteries; and perhaps also the Particles or Atoms of Cold, which are admitted through the Pores of the Skin, may act upon our Fluids, as it does upon Water, and occasion a Congelation of them, or a considerable Approach towards it.

If these Complaints are chiefly felt, which in Fact is the Case, rather on the extreme Parts than on others, it arises from two Causes, the principal one being, that the Circulation's being weaker at the Extremities than elsewhere, the Effect of those Causes, that may impair it, must be more considerably felt there. The second Reason is, because these Parts are more exposed to the Impressions from without than the others.

They occur most frequently to Children, from their Weakness and the greater Tenderness and Sensibility of their Organs, which necessarily increases the Effect of external Impressions. It is the frequent and strong Alteration from Heat to Cold, that seems to contribute the most powerfully to the Production of Chilblains; and this Effect of it is most considerable, when the Heat of the Air is at the same Time blended with Moisture; whence the extreme and superficial Parts pass suddenly as it were, out of a hot, into a cold, Bath. A Man sixty Years of Age, who never before was troubled with Kibes, having worn, for some Hours on a Journey, a Pair of furred Gloves, in which his Hands sweated, felt them very tender, and found them swelled up with Blood: as the common Effect of the warm Bath is to soften and relax, and to draw Blood abundantly to the bathed Parts, whence it renders them more sensible.

This Man, I say, thus circumstanced, was at that Age first attacked with Chilblains, which proved extremely troublesome; and he was every succeeding Winter as certainly infested with them, within Half an Hour after he left off his Gloves, and was exposed to a very cold Air.

It is for this Reason, that several Persons are never infested with Chilblains, but when they use themselves to Muffs, which are scarcely known in hot Countries; nor are they very common among the more northern ones, in which the extraordinary Changes from Cold to Heat are very rare and unusual.

Some People are subject to this troublesome Complaint in the Fall; while others have it only in the Spring. The Child of a labouring Peasant, who has a hard Skin, and one inured to all the Impressions of the Seasons and of the Elements, is, and indeed necessarily must be, less liable to Kibes, than the Child of a rich Citizen, whose Skin is often cherished, at the Expence of his Constitution. But even among Children of the same Rank in Life and Circumstances, who seem pretty much of the same Complexion, and live much in the same Manner; whence they might of Course be supposed equally liable to the same Impressions, and to the like Effects of them, there is, nevertheless, a very great Difference with Respect to their constitutional Propensity to contract Chilblains. Some are very cruelly tormented with them, from the setting in of Autumn, to the very End of the Spring: others have either none at all, or have them but very slightly, and for a very short Time. This Difference undoubtedly arises from the different Quality of their Humours, and the Texture of their whole Surface, but particularly from that of the Skin of their Hands; though we readily confess it is by no Means easy to determine, with Certainty and Precision, in what this Difference essentially consists.

Children of a sanguine Complexion and delicate Skin are pretty generally subject to this Disorder, which is often regarded much too slightly, though it is really severe enough to engage our Attention more; since, even abstracted from the sharp Pains which smart these unhappy Children for several Months; it sometimes gives them a Fever, hinders them from sleeping, and yet confines them to their Bed, which is very prejudicial to their Constitutions. It also breaks in upon the Order of their different Duties and Employments; it interrupts their innocent salutary Pleasures; and sometimes, when they are obliged to earn their daily Bread by doing some Work or other, it sinks them down to Misery. I knew a young Man, who from being rendered incapable by Chilblains, of serving out his Apprenticeship to a Watch-maker, is become a lazy Beggar.

Chilblains which attack the Nose, often leave a Mark that alters the Physiognomy, the Aspect of the Patient, for the Remainder of his Life: and the Hands of such as have suffered from very obstinate ones, are commonly ever sensible of their Consequences.

§ 464. With Respect, therefore, to these afflicting Tumours and Ulcerations, we should, in the first Place, do our utmost to prevent them; and next exert our best Endeavours to cure such as we could not prevent.