Of the compounds of mercury, the red-precipitate and Turbith-mineral act as irritants, besides possessing the property common to all mercurial compounds, of causing mercurial erethysm. But they are not escharotics, though generally termed such. That is, they do not chemically corrode the animal textures. The effects of red-precipitate have been variable. Mr. Allison relates the case of a girl who in a fit of jealousy swallowed thirty grains of it. Being immediately detected, an emetic was given, which operated freely, and subsequently the stomach-pump was used; but on neither occasion was any red powder brought away. She was attacked with burning pain in the stomach, which was removed by opium, and for a week she had a distaste for food, but no other symptom of consequence.[[989]] Mr. Brett has described a case, in which the symptoms were occasional vomiting, stupor, languid pulse, cold clamminess of the skin, afterwards severe cramps of the legs, tenderness of the abdomen, dysuria, and some purging, and on the third day ptyalism; but the patient recovered.[[990]] M. Devergie has given a case somewhat similar, but without any ptyalism having followed the irritant effects of the poison.[[991]] In 1840 I was consulted on the part of the Crown in the case of a girl, who, there was every reason to suppose, had been killed in twelve hours by red-precipitate. The symptoms towards the close were pain in the throat, inability to swallow, vomiting, and excessive prostration; extensive red patches were found on the villous coat of the stomach after death; and I detected mercury in the solid contents and likewise in the inner coat of the stomach. The case did not go to trial, because, although a man by whom she was pregnant came under some suspicion, it rather appeared that the deceased had herself swallowed the poison with the view of inducing miscarriage. Dr. Sobernheim has given the particulars of the case of a young man who died from swallowing an ounce of red-precipitate. He suffered for some hours from vomiting, diarrhœa, pain in the stomach, tenderness of the belly, and colic; next day he had no pain, but coldness, lividity, stiffness, and an imperceptible pulse; and he expired in thirty-three hours. The poison was found abundantly in the stomach and duodenum after death, and some grains of it rested upon little ulcers.[[992]] As to Turbith-mineral, two scruples will kill a cat in four hours and a half; and several instances of violent and even fatal poisoning with it are mentioned by the older modern authors.[[993]]
The white precipitate or chloride of mercury and ammonia is probably also irritant, though inferior in power to the preparations just mentioned. Two scruples given to a dog occasion vomiting, pain, and some diarrhœa; and cases are recorded of death in the human subject from less doses.[[994]] But there are no recent facts as to the activity of this compound, and the older cases, which would assign to it very great energy, are open to the objection that this preparation was in former times often impure.
The bichloride or corrosive sublimate is a powerful corrosive or irritant, according to the dose and state of concentration; and it also excites mercurial erethysm in a violent degree. The nitrates too are corrosive, and not inferior in activity to the bichloride, as may be inferred from Dr. Bigsby’s case, noticed at page [314].
The bicyanide or prussiate of mercury, from the researches of Ollivier, and an interesting case he has published of poisoning with it in the human subject, appears to resemble corrosive sublimate closely in all its effects, except that it does not corrode chemically. Twenty-three grains and a half proved fatal in nine days.[[995]] M. Thibert has described a case in which ten grains caused death in the same period of time.[[996]] The symptoms in both instances were those of severe irritation of the stomach, extensive inflammation of the organs in the mouth, and suppression of urine; and in Thibert’s case a small quantity of albuminous fluid was discharged from the bladder instead of urine.
The protochloride or calomel, and probably also the protoxide, are the most manageable of the preparations of mercury for inducing ptyalism. Calomel is also an irritant; that is, it causes irritation and inflammation in the alimentary canal when swallowed. This part of its properties as a poison will require a word or two of explanation.
Calomel is universally employed as a laxative, but to secure this effect being produced it is commonly combined with other purgatives. When given alone a few grains will in some constitutions induce a violent hypercatharsis; and larger, but still moderate, doses have with most people such a tendency to cause severe griping and diarrhœa as to have led to the practice of combining it with opium when the object is to salivate. These considerations clearly establish that calomel, in a moderate dose of five or ten grains, is an irritant.
It farther appears that in larger doses it is said to have occasionally produced very violent effects, nay, even death itself, by its irritant operation. Hoffmann has mentioned two instances where fifteen grains of calomel proved fatal to boys between the ages of twelve and fifteen. One of them had vomiting, tremors of the hands and feet, restlessness and anxiety, and died on the sixth day. The other, he merely mentions, died after suffering from extreme anxiety and black vomiting.[[997]] Another fatal case has been related by Ledelius in the German Ephemerides, which was caused by a dose of half an ounce taken accidentally. Vomiting soon ensued, and a sense of acridity in the throat; then profuse diarrhœa to the extent of twenty evacuations in the day; next excessive prostration of strength and torpor of the external senses; and death followed in little more than twenty-four hours.[[998]] Wibmer quotes Vigetius, an author of the beginning of last century, for a similar case, likewise fatal, which was occasioned by half an ounce,—also Hellweg, a writer of the previous century, for the case of a physician, who took an ordinary medicinal dose by way of experiment, and died in five hours under all the symptoms of violent irritant poisoning.[[999]]
These observations being kept in view, what explanation will the toxicologist give of the effects which in modern times have been ascribed to large doses of calomel? It was stated not many years ago by several East India surgeons, apparently with the universal assent of their brethren in later times, that this drug in the dose of a scruple administered even several times a day, is not only not an irritant, but even on the contrary a sedative;[[1000]] and that in some diseases, for example yellow fever, it has been given in the dose of five, ten, or twenty grains, four or six times a day, till several hundred grains were accumulated in the body, yet without causing hypercatharsis, nay, with the effect of checking the irritation which gives rise to black vomit in yellow fever, and to the vomiting and diarrhœa observed in the cholera of the East. It is quite impossible for a European physician to doubt these statements; for all practitioners in hot climates concur in them, and now that analogous practices have been transferred to Britain, repeated opportunities have occurred for establishing the fidelity of the original reporters. Some American physicians, advancing beyond the Hindostan treatment, have since given calomel in bilious fever in the dose of forty grains, one drachm, two drachms, and even three drachms, repeatedly in the course of twenty-four hours for several days together,—and with similar phenomena. In one instance 840 grains were given in the course of eight days in these enormous doses. The largest dose was three drachms; and it was followed by only one copious evacuation, and that not till after the use of an injection.[[1001]] This practice appears not to have been altogether unknown in former times. Ledelius, the author formerly quoted, states, that he had been accustomed to give doses of a scruple, and that Zwölffer even gave a drachm in one dose.[[1002]]
It must be also added, that while the facts quoted above from Hoffmann, Ledelius, and others assign to single large doses a powerful and dangerous irritant action, very different results have been occasionally observed in recent times where even so large a quantity as one or two ounces had been taken. Thus, in the case of a lady mentioned by Wibmer, who took by mistake the enormous quantity of fourteen drachms, although acute pain in the belly ensued, together with vomiting and purging, these symptoms were speedily subdued by oleaginous demulcents; and after a smart salivation, she recovered entirely in six weeks.[[1003]] Another case has been related by Mr. H. P. Robarts, where an ounce was swallowed by a young lady by mistake for magnesia, with no other effect than nausea at first, rather severe griping and slight tenderness of the belly afterwards, and subsequently languor, headache and indigestion; yet the powder was retained two hours.[[1004]]
It is impossible in the present place to enter into the physiological action of calomel as a remedy; but every one must be satisfied that, with all which has been already written, much still remains to be done before the facts now mentioned can be explained satisfactorily. Can the violent effects described by Hoffmann, Ledelius and Hellweg have arisen from the calomel having been imperfectly prepared and adulterated with a little corrosive sublimate? Or may they be explained by reference to the fact, that the presence of hydrochlorates in solution, particularly hydrochlorate of ammonia, tends to convert calomel into corrosive sublimate.[[1005]] Mr. Alfred Taylor has made some experiments, to show that the latter explanation will not suffice.[[1006]]