To meet the comprehensive views of the forensic toxicologist, an arrangement would seem to be required, that should at once embrace the several objects which we have just enumerated; for the data from which the proof of poisoning is to be inferred, are, as we have often stated, highly complicated in their relations. No such classification, however, can be accomplished, and we are therefore compelled to select one which may approach the nearest to our imaginary fabric. That which was proposed by _Fodéré_,[210] and adopted, with some trivial alteration in the order of succession of the classes, by _Orfila_, in his celebrated system of toxicology, although it has many defects and some errors, nevertheless merits the preference of the forensic physician; its basis is strictly pathological, and yet it distributes the different poisons, with some few and unimportant exceptions, in an order corresponding with that of their natural history.
The first two classes, for instance, present us with substances of a mineral origin; the third and fourth, with those which are principally of a vegetable nature; and the sixth, with objects chiefly belonging to the animal kingdom. The importance of acknowledging a division, which has a reference to the three great kingdoms of Nature, is perhaps greater than the reader may anticipate; for in enumerating the various experiments to be instituted for the detection of poisons, we are, by such an arrangement, enabled to bring together a connected series of processes, nearly allied to, intimately connected with, and in some respects, mutually dependant upon each other.
The following is the arrangement of _Fodéré_ as modified by _Orfila_: viz. Cl. I, _Corrosive_, or _Escharotic poisons_. Cl. II, _Astringent poisons_. Cl. III, _Acrid_ or _Rubefacient poisons_. Cl. IV, _Narcotic_ or _Stupefying poisons_. Cl. V, _Narcotico-Acrid poisons_. And Cl. VI, _Septic_ or _Putrefying poisons_.
Class I. CORROSIVE or ESCHAROTIC POISONS. Such as corrode and burn the textures to which they are applied. When internally administered they give origin to the following symptoms: violent pain accompanied with a sense of heat and burning in the stomach, and throughout the whole extent of the alimentary canal; frequent vomitings, often sanguineous, and alternating with bloody diarrhœa, with or without tenesmus; the pulse hard, small, frequent, and at length imperceptible; an icy coldness of the body; cold sweats; a great anxiety and oppression at the præcordia; and hiccup. Sometimes the heat of the skin is intense, the thirst inextinguishable, and the unhappy patient is tormented with Dysuria and Ischuria, violent cramps in the extremities, and horrid convulsions, which are relieved only by death. Such are the general symptoms by which this species of poisoning is characterised; the rapidity with which the symptoms terminate their course, will depend upon the violence of the dose, and the particular species of poison which has produced them; there are, moreover, other symptoms which will be more conveniently described, when we come to speak of the effects of corrosive poisons individually. In this class are ranked the following substances. METALS. I. Arsenic—1. _Arsenious Acid_, or white oxide of Arsenic. 2. _Arsenites_, or combinations of that acid with _salifiable bases_. 3. _Arsenic Acid._ 4. _Arseniates_, or combination of the preceding acid with the bases. 5. _Sulphurets of Arsenic_, or _Orpiment_ and _Realgar_. II. Mercury—1. _Corrosive Sublimate of Mercury_, or _Oxy-muriate of Mercury_. 2. _Red Oxide of Mercury._ 3. _Red Precipitate_, or _Nitric Oxide of Mercury_. 4. Other preparations of Mercury. III. Antimony—1. _Tartarized Antimony_, or _Tartar Emetic_. 2. _Oxide_ _of Antimony._ 3. _Antimonial Wine._ 4. _Muriate of Antimony_, or _Butter of Antimony_. IV. Copper—1. _Blue Vitriol_, or _Sulphate of Copper_. 2. _Verdegris._ 3. _Oxide of Copper._ 4. Other preparations of Copper. V. Tin—1. _Muriate of Tin._ VI. Zinc—1. _Sulphate of Zinc_, or _White Vitriol_. 2. _Oxide of Zinc._ VII. Silver—1. _Nitrate of Silver_, or _Lunar Caustic_. The Concentrated Acids—1. _Sulphuric._ 2. _Muriatic._ 3. _Nitric._ 4. _Phosphoric_, &c. Hot Liquids—1. _Boiling water._ 2. _Melted Lead._ The Caustic Alkalies—1. _Potass._ 2. _Soda._ 3. _Ammonia._ The Caustic Alkaline Earths—1. _Lime._ 2. _Baryta._ 3. _Muriate_, and _Carbonate of Baryta_. Cantharides. Phosphorus.