Thompsonians have made much use of the popular prejudice against _mineral_ medicines. This prejudice has arisen in part from the evils which have been seen to result from the _abuse_ of calomel. This remedy is so effectual an one in many diseases, that it has been used more freely, and with less caution, than it should be; and disastrous effects have sometimes followed this abuse of it. But the same reasoning which prohibits the cautious use of this article, on account of the results which come from its incautious use, would prohibit the use of horses, fire, steam, &c., because, through carelessness and want of skill, horses run away, conflagrations take place, and steam boilers burst. Still this groundless reasoning is applied by a large portion of the community to this remedy. And this prejudice against calomel has been extended to mineral medicines generally. So extensive is this prejudice, that the quack of every name is sure to appeal to it, and he, therefore, puts in his advertisement, the assurance that his medicine is ‘entirely vegetable,’ as a necessary passport to public favor. Many physicians, too, disgracefully yield to the prejudice of the people in this respect. They pretend to give no calomel, or almost none of it; and yet, such physicians generally give more of this article, than those who pursue an open and manly course on this subject. In the clamor which has been raised against ‘mineral doctors’ Thompsonians have been among the loudest. They uniformly speak of minerals, as if they were deleterious _because_ they are minerals. Their chemistry, which, as you have seen, recognizes the existence of only four elements, has not, I suppose, taught them, that their own bodies are partly composed of minerals, that there is lime in the bones, and iron in the blood, that minerals exist in many articles of food, that their good wives sometimes put a mineral of even deadly power into the bread which they eat, and that they daily use as a condiment one of these same luckless minerals. They speak of ‘mineral doctors’ as the poisoners of the race, while they claim so perfect a safety in the use of their _vegetable_ remedies, that no carelessness or want of skill can make them produce any bad results. There seems to be a quite a general impression abroad in the community, that there is a _harmlessness_ in vegetable remedies that does not attach to mineral medicines, and that their effects are of a _less abiding_ character. Nothing can be more untrue. Let us look for a moment at these two points.