Secondary Phthisis Pulmonalis remains yet to be treated of. Under this order, should be included every form of Consumption, in which the system has become debilitated by any cause, and the lungs in consequence become affected. I would exclude from it that form of the disease occurring after measles, scarlatina, and some other eruptive diseases, which I would consider as primary Phthisis Pulmonalis; because, in those cases, the lungs do not become affected merely in consequence of debility, but these diseases seem rather to act as exciting causes, in constitutions already predisposed to Consumption; while in secondary Phthisis, the affection of the lungs is only one symptom of the general disease, which is wasting the body. Nor would the treatment, which will be advocated in the latter form, be proper in the cases alluded to. They require that, which should be used in the first species of Phthisis, and which has already been detailed. The reason, why the lungs become affected in consequence of debility induced by particular causes, I would not attempt to explain. It is one of those laws of the constitution, not better understood, than why particular parts are successively affected in consequence of syphilis, or that the breasts and lower extremities are more liable to disease than other parts, except the uterus, in females after parturition. Many laws of this kind exist in the human constitution, of whose effects, we are every day made sensible, but of the cause of which we are totally ignorant. One of the most frequent causes of Secondary Phthisis, is Chlorosis, that disease which occurs in young females, in consequence of Retention of the menses. The constitution not having sufficient vigour to produce this evacuation at the proper period, if any predisposition to Phthisis exist, a determination takes place to the lungs, producing Phthisical disease. This case is not analogous to Consumption produced by Suppression of the menses, after they have been once established; for in that instance the suppression is not generally induced by debility, but by cold, or some other cause, not acting merely by weakening the patient; and it produces active inflammation of the lungs. But in the case before us, the affection of the lungs is merely a symptom of the want of vigour in the constitution, which shews itself in retention of the menses. Accordingly, in the treatment of this disease, our attention must not be directed primarily to the affection of the lungs, but to the state of the system, the cause of that affection.