From two to three grains have proved fatal, but an instance is recorded of recovery after a dose of sixty grains. Death may ensue in half an hour, or may be delayed for nearly three weeks; the usual time is perhaps from twelve to forty-eight hours. There are some cases in which little or no morbid appearances are to be seen. Usually, however, traces of irritation will be discoverable. In the mouth and throat they are often wanting. The inner surface of the stomach may be red and inflamed, or blackish from the extravasation of blood, or softened, or in some cases thickened, with the rugæ raised and corrugated. Ulceration of the coats of the stomach is but rarely met with, unless the patient have survived nearly two days. The mucous secretion is generally increased in quantity, sometimes thin, and viscid, as in its natural state, but sometimes solid, as if coagulated. In the latter case, it forms either a uniformly attached pedicle, or loose shreds floating among the contents. A very common appearance, is the presence of a sanguinolent fluid, or even actual blood in the cavity of the stomach. The poison itself may also be found within the stomach. The intestines may be congested and inflamed throughout their whole length, but most frequently only in the duodenum and rectum. Within the chest, redness of the pleura, redness and congestion of the lungs, have been noticed. In general, arsenic retards the process of putrefaction after death. The forms in which arsenic is most frequently used for the purpose of poisoning, are arsenious acid, and the arsenite of copper, Scheele’s green. =Corrosive Sublimate.= The appearances observed in the bodies of persons killed by this poison, are very similar to those excited by the irritant poisons already noticed. The mouth and throat are more frequently affected than by arsenic. The tongue is often shrivelled, and the papillæ at its root greatly enlarged. The mucous membrane is swollen and whitened. The same appearances are generally noticed in the œsophagus. The coats of the stomach and intestines, more particularly the colon and rectum, have been found congested and inflamed, and sometimes destroyed, either by a chemical decomposition of the tissues, or by ulceration. The bladder is often excessively contracted; the kidneys usually much congested and inflamed. Inflammation of the peritoneum, and effusion into its sac are frequent results of poisoning with corrosive sublimate. =Hydrocyanic Acid.= The poisons whose energy depends upon the presence of this acid, surpass almost all others in rapidity of action, and the minuteness of the quantity in which they operate. The lesions produced are uncertain. The spine and neck are stiff, the abdomen retracted, the skin usually livid.