Alas, my friend! how is it possible that physicians should avoid mistakes? If the ablest mechanic were to attempt to remedy the irregular movements of a watch, while he remained ignorant of the structure and manner of acting of some of the principal springs, would he not be in danger of doing harm instead of good? Physicians are in the situation of such a mechanic; for, although it is evident that the nerves are the organs of motion and sensation, yet their structure is not known. Some anatomists assert they are impervious cords; others, that they are slender tubes, containing a fluid. But what the nature of this fluid is; whether it serves only to nourish the nerves themselves, or is the medium by which they convey feeling and the power of motion to other parts, is not ascertained even by those who argue for its existence; far less is it explained in what manner ideas, formed within the brain, can, by the means of solid cords, or by a fluid contained in tubes, communicate motion at pleasure to the legs and arms. We are ignorant why the will, which has no influence over the motion of an animal’s heart, should find the feet obedient to her dictates; and we can no more explain how a man can move one leg over the other by volition, or the mere act of willing, than how he could, by the same means, move Ossa on the top of Olympus. The one happens every moment, the other would be considered as a miracle; but they are equally unaccountable. While parts so infinitely essential to life are not understood, instead of being surprised that so many diseases baffle the skill of the physician, we have more reason to be astonished that any can be alleviated or cured by his art. The pen of the satirist, no doubt, may be fairly aimed against the presumption and ignorance of many individuals of this, as of every other profession; but cannot with justice be directed against the art itself: since, in spite of the obscurity which still involves some parts of the animal economy, many disorders are relieved, and some of the severest and most disagreeable to which the human body is liable, are cured with certainty by the art of medicine. Unfortunately for mankind, and in a particular manner for the inhabitants of Great Britain, the pulmonary consumption is not of the number. This disease may originate from various causes: 1st. An external bruise or wound. 2d. The disease called pleurisy, including in that term an inflammation of the lungs themselves, as well as the membrane which covers them. 3d. The bursting of some of the blood-vessels of the lungs, independent of external injury, and owing to a faulty conformation of the chest, and the slenderness of the vessels. 4th. Certain small tumours, called tubercles, in the lungs. The first cause I have mentioned is an external bruise or wound.