It remains for us to make a few observations upon the abuse of these remedies, for, notwithstanding the popular adage that “_Blisters are always safe things_,” that “_if they do no good, they can do no harm_,” they will be found, like all other potent applications, capable of producing much mischief when directed by unskilful hands. In stages of high vascular excitement in the pulmonary organs, blisters have increased the irritation they were designed to allay, and in some cases have promoted a tendency to effusion; in the treatment of acute Hydrocephalus the common practice of blistering the head appears very questionable, and has too often, I am well persuaded, accelerated the fatal termination, by increasing the disposition to serous effusion. ISSUES (_Fonticuli_) and SETONS (_Setacea_[176]). The effects of these processes bear a strong analogy to those which are produced by Vesicatories; they are, however, more permanent, and are on that account better adapted to the relief of those chronic affections which would seem to require a remedy of long continued influence. In pulmonary affections, for instance, a seton in the side is frequently attended with very considerable benefit. The popular belief in humoral pathology, which continues to influence the mass of mankind, has perhaps assigned to these remedies a greater share of credit than that to which they are really entitled, but it must still be acknowledged that when an ulcer having existed a great length of time, is healed or _dried up_, or any constitutional discharge is suddenly checked, the health may become affected. In such cases the establishing a discharge by means of an Issue is undoubtedly a safe, and often a beneficial operation. III. OF CHEMICAL REMEDIES.