Acetate of lead has all the effects upon the system which have already been described as characterizing the preparations of lead in general. In large doses, or unsuitably applied, it is irritant; but, when so employed as to obtain its peculiar influence, it is astringent and sedative.

1. Its irritant effects are shown when it is applied in strong solution to delicate surfaces, as to the conjunctiva, the urethra, or the skin denuded of the cuticle, or when taken too largely into the stomach. Orfila found it, when introduced in large quantity into the stomach of dogs, to occasion fatal inflammation; and the gastric and intestinal mucous membrane was observed to be whitened by its chemical action. In man, when taken in excessive doses, it generally produces vomiting, burning pain in the oesophagus and stomach, and tenderness in the epigastrium, usually followed by severe griping in the bowels, and sometimes by convulsions, coma, and local palsy, especially if the bowels arc not acted on. Its dangers, however, as an irritant poison, were formerly much overrated; for, though often taken accidentally in quantities varying from a drachm to an ounce, no fatal case is, I believe, on record from its immediate effects. Being frequently prescribed for external use, at the same time that Epsom salt is directed as a cathartic, it has occasionally been swallowed instead of the latter, which, in its turn, has been applied locally; and this accident should be carefully guarded against by the practitioner. I was once called to a case of the kind, in which two drachms of the acetate had been swallowed, with the effect of producing severe gastric pain; but, before I reached the patient, a dose of sulphate of zinc had been taken, which caused vomiting, and no injury ensued. What quantity, therefore, may be considered as poisonous, in reference to the irritant action, it is impossible to say; but this much may be inferred, that there is less danger to life from its temporary influence in an excessive dose, than from the same amount given in minute doses frequently repeated, and spread over a considerable length of time. The mode of treating its poisonous effects, as an irritant, has been given under the general head of the preparations of lead. The best antidote is sulphate of magnesia, or sulphate of soda.

* I have verified by experiment the decomposition of perfectly neutral and pure acetate of lead by carbonic ncid. The whole of the salt, however, is not decomposed; as, when the acetic acid has attained a certain degree of excess, it appears to prevent the further action of the carbonic acid.

2. It has been doubted whether acetate of lead is capable of producing the poisonous constitutional effects of the metal, especially if protected against conversion into the carbonate by an excess of acetic acid. Certainly, considerable doses have been given daily, and continued long, without any observable influence on the general system; and the extreme fear formerly entertained by many, as to the danger of its internal use as a medicine, has been shown to have had little foundation in fact. Nevertheless, that it is capable of producing, when incautiously or recklessly employed, all the dangerous constitutional effects of lead, has been abundantly proved by experience. Dr. Mulford, of Camden, N. J., many years ago, assured me that he had witnessed two cases of colica picto-num resulting from its medicinal use; and many instances to the same effect have since been placed on record. Death has occurred in one instance from colic and paralysis, in a boy of fifteen, to whom from one to eight grains, in divided portions, were given daily until the whole amounted to somewhat more than two drachms. In the Provincial Medical and Surgical Journal (June 27th, 1849), Dr. William Norris, of Stourbridge, relates an occurrence in which nearly a thousand persons were more or less poisoned, in consequence of a mistake made by a baker, who mixed thirty pounds of acetate of lead, instead of the same quantity of alum, with sixty or eighty sacks of flour. It may be said that, in this case, the acetate was decomposed before being taken. It probably was so; but not more certainly than it is decomposed in the stomach, after having been swallowed. Dr. L. S. Jones, of Accomack, Va., has related a case of obstinate colica pictonum, which resulted from thirty grains of the acetate, given in four days, though care was taken to accompany the use of the medicine with vinegar. (Stethoscope, i. 6G4.) It is proper, therefore, to observe some caution in the use of this medicine. With such caution, I believe it may always be given safely. I have been in the habit of using acetate of lead for forty years, have given it in a vast number of cases, and though, after a certain continuance of the medicine, griping pains in the bowels have generally occurred, often with nausea and general malaise, I have never witnessed more than one instance in my practice, in which anything that could properly be denominated colica pictonum has resulted. I have not unfrequently prescribed two grains every two hours through the day, and continued it for several days, sometimes even for weeks, before any sign of its constitutional effects were evinced. I have, however, always been careful to suspend the medicine as soon as the effects on the stomach and bowels just referred to, or a blue discoloration of the gums, have been noticed.