3. The third variety of poisoning with mercury comprehends all the forms of what is called mercurial erethysm. Without endeavouring to settle the precise meaning of this term, which is now used in rather a vague sense, I shall consider under the present head all the secondary and chronic effects of mercury. These may be caused by any of its preparations, but are most frequently seen as the consequence of its milder compounds, either given medicinally in frequent small doses, or applied continuously to the bodies of workmen who are exposed by their trade to its fumes.
The secondary and chronic effects of mercury are multifarious enough in reality; but if credit were given to all that has been written, and is still sometimes maintained on this subject, almost every disease in the nosology might be enumerated under the present head; for there is scarcely a disease of common occurrence, which has not been imputed by one author or another to the direct or indirect operation of mercury. The present remarks, however, will be confined as much as possible to what is well ascertained, and bears on the medical evidence of poisoning with mercury, or is important in regard to medical police. With this view, salivation and its concomitants, the most usual of the secondary effects of mercury, will first be treated of. Some observations will then be made on the shaking palsy, or mercurial tremor, which is caused in those who work with mercury. And in conclusion, a short view will be taken of the other diseases which are more indirectly induced by this poison, as well as some which have been ascribed to it on insufficient grounds. This being done, the mode of action of mercurial poisons will be resumed, and a description given of their relative effects when introduced by different channels and in different chemical forms.
Of Mercurial Salivation.—Mercurial salivation may be caused by any of the preparations of mercury, and either by a single dose or by frequently repeated small doses. It may be caused by corrosive sublimate as the secondary stage of a case which commenced with inflammation in the alimentary canal; or it may be the first sign of mercurial action, as in the medicinal mode of administering calomel and blue pill. Even in the latter case a single dose, and that not large, may be sufficient to induce ptyalism of the most violent kind. When induced by a single dose it usually commences between the beginning of the second and end of the third day, rarely within twenty-four hours. But an extraordinary case is mentioned by Dr. Bright, where five grains, put on the tongue in apoplexy and not washed over, excited in three hours most violent salivation, with such swelling of the tongue that scarifications became necessary.[[920]] It commences with a brassy taste and tenderness of the mouth, swelling, redness, and subsequently ulceration of the gums; peculiar fetor of the breath; and at last an augmentation is observed in the flow of the saliva, commonly accompanied with fulness around the lower jaw. These symptoms increase more or less rapidly. Sometimes they are very mild; nay, this form of the secondary effects of mercury may consist in nothing else than brassy taste, tenderness of the mouth, redness of the gums, and fetor. On the other hand, the symptoms are often very violent, the salivation being profuse, the face swelled so as to close the eyes, and almost fill up the space between the jaw and clavicles, the tongue swollen so as to threaten suffocation, the inside of the mouth ulcerated, nay gangrenous, and at times the gangrene extends over the face. It is not uncommon to observe severe and extensive ulceration without particular increase of the saliva.
These local affections are almost always accompanied with more or less constitutional disorder. If severe, they are attended with the symptomatic fever proper to inflammation and gangrene, from whatever cause they spring. But independently of that, mercurial salivation is accompanied, and indeed commonly preceded, by a constitutional disorder or symptomatic fever of its own, which occasionally exhibits some peculiarities. The mildest affection of the mouth and salivary glands is very generally preceded by some exaltation of the pulse and temperature, and other symptoms of fever. But when the local disorder begins violently, and above all when this takes place by idiosyncrasy from small doses of mild preparations, there is often great rapidity of the pulse, irregular action of the heart, and various nervous disorders possessing the hysteric character,—all of which, except the quick pulse, will sometimes gradually abate or even disappear, when the salivation is fairly established.
The phenomena of ordinary mercurial salivation being familiar to every practitioner, it is unnecessary to quote here any illustrative example; but the following instance may be given to exemplify its most malignant forms. A patient of Mr. Potter of Chipping-Ongar, in Essex, after taking eighteen grains of blue pill in divided doses during three days, was seized with excessive salivation and great constitutional disturbance, indicated by offensive evacuations, copious sweating, bleeding from the nose, purple spots on the skin, dilated pupils, and such severe local disease that the teeth dropped out, and he expired six days after mercurial action set in.[[921]]
As the phenomena of mercurial salivation have been often known to lead to important evidence and much contrariety of opinion upon trials, it will be necessary to dwell at some length on some parts of the subject.
In the first instance, then, the dose which is required to bring on salivation may be noticed. It is needless to mention the ordinary quantity required in mercurial courses. A more useful object of consideration is the departure from the ordinary rule. One of the most common and important of these deviations is excessive sensibility to the action of mercury, in consequence of which the individuals who have this idiosyncrasy may be profusely salivated by one or two small doses even of the mildest preparations. Three grains of corrosive sublimate divided into three doses have caused violent ptyalism.[[922]] Fifteen grains of blue pill, taken in three doses, one every night, have excited fatal salivation.[[923]] Nay, two grains of calomel have caused ptyalism, extensive ulceration of the throat, exfoliation of the lower jaw, and death.[[924]] Three drachms of mercurial ointment applied externally have caused violent ptyalism and death in eight days. On the other hand, it is well known that some constitutions resist the action of mercurials very obstinately, so as even sometimes to appear incapable of being salivated at all. I have more than once met with cases of the last description, where mercurial courses had been continued for three months and upwards without avail. It may be added, that, except in constitutions naturally predisposed to suffer from a few small doses, a few large doses do not appear apt to excite severe salivation, or even to cause any at all. This has been clearly shown in the course of the practice lately introduced of administering calomel in doses of a scruple. On that subject more will be said by and by. At present I may mention, that, in conformity with the practice alluded to, I have several times, in various diseases, given eight or ten grains of calomel five or six times a day for two or three days together, without observing that ptyalism was apt to ensue.
The next point to be considered is, whether mercurial salivation can be confounded with any other affection. In a very difficult case of poisoning which was tried here in 1817, that of William Patterson for murdering his wife,[[925]] it appeared probable that he had given her repeatedly large doses of calomel. But the proof of this was circumstantial only, and an important circumstance in the chain of evidence was a deposition to the occurrence of salivation during the woman’s illness. This fact, however, rested on the skill and testimony of a quack doctor only; and the admissibility of such a person to decide on a point of this nature, will depend on the facility with which the true mercurial form of salivation can be recognised. This statement will show the practical object of what is to follow.
Many other causes may excite a preternatural flow of saliva. Several other poisons may have that effect, for example, preparations of gold, preparations of copper, antimony, croton-oil, and foxglove: foxglove has been known to cause violent salivation for three weeks.[[926]] Opium too has occasionally excited salivation,[[927]] and also hydrocyanic acid and iodide of potassium.
Even a common sore throat, if the swelling and pain are so great as to render swallowing very difficult and distressing, may be accompanied, as every physician must have remarked, with a profuse flow of saliva; and in the ulcerative stage there is also often a fetor that is hardly distinguishable from the mercurial kind. In the ulceration of the mouth called cancrum oris there is some salivation with great fetor of the breath.