From these observations, it will, I presume, appear, first, That when a part is incapable of performing the actions necessary for its preservation in a state of health, it generally slowly assumes the inflammatory state, which goes on to ulceration; but the part being unable to support its natural action, can much less perform the actions necessary for restoration from this morbid condition, which, therefore, continues permanently and progressively increasing; that the nature of this unhealthy action is not always the same, but admits of variations dependent upon certain conditions in the previous state of the part affected, with regard to which we are greatly in the dark. Cancer, pseudo-cancer, spongoid inflammation, &c. are some of these variations. Secondly, Cancer, and all these variations, are originally, in the strictest sense of the word, local diseases, depending neither upon any constitutional affection, nor the presence of any general cause. They do, however, in progress of time, affect not only parts in their vicinity, but also the system in general, producing, by means of sympathetic actions, specific hectic affections, as has been formerly explained, when treating of simple hectic. They likewise spread over more surface in the part at first affected, and produce the same morbid actions without variation, by means of the sympathia consociationis serpens. They also induce a similar disease in the nearest lymphatic glands, by absorption. _Of the Prevention and Treatment of Cancer._