Arsenic belongs to those poisons which act with nearly the same energy whatever be the organ or texture to which they are applied. The experiments of Sproegel,[573] repeated by Jaeger,[574] and by Sir Benjamin Brodie,[575] leave no doubt, that when applied to a fresh wound it acts with at least equal rapidity as when swallowed. Although in such circumstances the signs of irritation are often distinct, yet the symptoms are on the other hand sometimes more purely narcotic than by any other mode of administering it,—Sir B. Brodie in particular having observed loss of sense and motion to be induced, along with occasional convulsions. Arsenic likewise acts with energy when applied to the conjunctiva of the eye, as was proved by Dr. Campbell. It acts too with great energy when inhaled in the state of vapour into the lungs, or in the form of arseniuretted-hydrogen. It farther acts with violence through the mucous membrane of the vagina, producing local inflammation, and the usual constitutional collapse. These facts were determined experimentally by the Medical Inspectors of Copenhagen on the occasion of a singular trial which will be noticed afterwards. Arsenic also acts, as may easily be conceived, when injected into the rectum. And farther, it acts as a poison, when it is applied to the surface of ulcers, yet certainly not under all circumstances. Its power of acting through the unbroken skin has been questioned. Jaeger found that, when it was merely applied and not rubbed on the skin of animals, it had no effect.[576] But some cases will be afterwards mentioned which tend to show that the reverse probably holds in regard to man. According to the last-mentioned author, who is the only experimentalist that has hitherto examined the subject consecutively, arsenic is most active when injected into a vein, or applied to a fresh wound, or introduced into the sac of the peritonæum; it is less powerful when taken into the stomach; it is still less energetic when introduced into the rectum; and it is quite inert when applied to the nerves. It is a striking fact in the action of that poison that, whatever be the texture in the body to which it is applied, provided death do not ensue quickly, it almost always produces symptoms of inflammation in the stomach; and on inspection after death traces of inflammation are found in that organ. In some instances of death caused by its outward application, the inflamed appearance of the stomach has been greater than in many cases where it had been swallowed. Sproegel met with a good example of this in a dog killed by a drachm applied to wounds. The whole stomach and intestines, outwardly and inwardly, were of a deep-red colour, blood was extravasated between the membranes, and clots were even found in the stomach.[577]