Class II. ASTRINGENT POISONS. They occasion a remarkable and unrelenting constriction of the great intestines, especially the colon, so as to resist the operation of the most powerful cathartic remedies. Violent cholics ensue, and partial paralysis; in the end if the dose be sufficiently large, or if small doses have been frequently repeated, they will excite inflammation of the alimentary canal, but it is not succeeded by that disorganization which generally characterises the operation of poisons, belonging to the preceding division. We rank under the present class only the preparations of Lead, viz. 1, _Acetate of Lead_, or _Sugar of Lead_; 2, _Oxides of Lead_; _Red Lead_; _Litharge_; 3, Various Saturnine impregnations. Class III. ACRID, or RUBEFACIENT POISONS. These poisons are known by their producing an acrid taste, more or less pungent and bitter; a burning heat, and considerable dryness in the mouth and fauces; and a constriction, more or less painful, in the throat. Acute pains are, after a short interval, experienced in the stomach and bowels, which are quickly followed by copious vomiting and purging, and which continue, with the most painful efforts, long after the alimentary canal has been completely evacuated. A few hours after, phenomena are observed which indicate a lesion of the nervous system, such as vertigo, dilated pupils, dejection, insensibility, laborious respiration, and death. The lesions of texture, occasioned by the action of _Acrid_ poisons, have the greatest analogy to those produced by _Corrosive_ poisons; in fact, says _M. Orfila_, “we do not hesitate to declare, that there exists a perfect identity between the alterations of the digestive canal produced by the poisons of these two classes, when introduced into the stomach.” The substances included under this class belong, for the most part, to the vegetable kingdom, such as _Scammony_, _Camboge_, _Black_ and _White Hellebore_, _Bryony_, _Euphorbium_, Seeds of the _Ricinus_, _Iatropa Curcas_ (Indian nut), _Croton Tiglium_, _Squill_, _Aconite_, &c. &c. Class IV. NARCOTIC, or STUPEFYING POISONS. Such as occasion stupor, drowsiness, paralysis, or apoplexy, and convulsions. They do not produce any change in the structure of parts to which they are applied. _M. Orfila_ has satisfactorily ascertained that no alteration can be discovered, on dissection, in the digestive canal of persons who have swallowed any one of the poisonous substances of this class. Class V. NARCOTICO-ACRID POISONS. This division, as its name implies, is intended to receive such substances as produce the united effects of those belonging to the two preceding classes, acting for instance at the same time, as narcotics and rubefacients. Amongst the articles of this class the following may be enumerated, _Belladonna_, _Stramonium_, _Tobacco_, _Foxglove_, _Hemlock_, _Nux Vomica_, _Camphor_, _Cocculus Indicus_, certain _Mushrooms_, _Alcohol_, &c. &c.