There are some diseases of which it is difficult to discover exactly the cause, and consequently it must be so to determine the indication, and to regulate the method of cure; and yet such diseases are easily cured when those points are once ascertained. It is not so of the _Tabes dorsalis_. That disease is known, its cause is known: (it is, as M. LEWIS observes, a particular sort of consumption, _of which the proximate cause is a general debility of the nerves_:) the indication is easily formed, and there can be no great differing in opinions about the essential method of cure: and yet even the best methods often fail; this is a reason the more for fixing the particulars with exactness. A general relaxation of the fibres, a weakness of the nervous system, a depravation of the fluids, are the causes of this evil. It depends on the weakening of all the parts; the great requisite is to restore strength to them; this is the sole indication, which has again its respective subdivisions, derived from the different parts that are weakened; but as the same remedies are of service in them all, it is needless to particularise those subdivisions here, which has been already done in the course of this work. Those who are totally ignorant of physic, and who nevertheless talk more of it than those who understand it, will probably think it very easy to accomplish this indication; and that with good aliments, and the cordials with which pharmacy abounds, it is a matter of great facility to restore strength; while, on the contrary, sad experiences have taught our greatest physicians that nothing could be more difficult.