1. Inorganic.
    1. Corrosive acids and alkalies, and caustic salts (carbolic and oxalic acids also).
    2. Irritant—practically all the metals and the metalloids (I. Cl. Br. P.).
  2. Organic.
    1. 1. Irritant
    2. {
      1. (a) Somniferous—opium and its alkaloids.
      2. (b) Deliriant—belladonna, hyoscyamus, stramonium, cannabis, cocaine, cocculus, camphor, fungi.
      3. (c) Inebriants—alcohol, ether, chloral, carbolic acid (weak), benzol, aniline, nitro-glycerine.
    3. Animal—venomous bites, food poisoning, cantharides.
      Vegetable—all strong purgatives, hellebores, savin, yew, ergot, hemlock, laburnum, bryony, etc.
      1. (a) Neural—conium, lobelia, tobacco, physostigma.
      2. (b) Cerebral—hydrocyanic acid.
      3. (c) Cardiac—aconite, digitalis, colchicum, veratrum.
    4. Neuronic.
    5. Sedative or depressant.
    6. Excito-motory or convulsives—nux vomica, strychnine.
    7. Vulnerants—powdered glass.
  3. Asphyxiants.
    1. Poisonous and irrespirable gases.
1. Irritant{Animal—venomous bites, food poisoning, cantharides.
Vegetable—all strong purgatives, hellebores, savin, yew, ergot, hemlock, laburnum, bryony, etc.

IV.—EVIDENCE OF POISONING

It may be inferred that poison has been taken from consideration of the following factors: Symptoms and post-mortem appearances, experiments on animals, chemical analysis, and the conduct of suspected persons.

  1. Symptoms in poisoning usually come on suddenly, when the patient is in good health, and soon after taking a meal, drink, or medicine. Many diseases, however, come on suddenly, and in cases of slow poisoning the invasion of the symptoms may be gradual.
  2. Post-Mortem Appearances.—These in many poisons and classes of poisons are characteristic and unmistakable. The post-mortem appearances peculiar to the various poisons will be described in due course.
  3. Experiments on Animals.—These may be of value, but are not always conclusive.
  4. Chemical Analysis.—This is one of the most important forms of evidence, as a demonstration of the actual presence of a poison in the body carries immense weight. The poison may be discovered in the living person by testing the urine, the blood abstracted by bleeding, or the serum of a blister. In the dead body it may be found in the blood, muscles, viscera—especially the liver—and secretions. Its discovery in these cases must be taken as conclusive evidence of administration. If, however, it be found only in substances rejected or voided from the body, the evidence is not so conclusive, as it may be contended that the poison was introduced into or formed in the material examined after its rejection from the body, or if the quantity be very minute it will be argued that it is not sufficient to cause death. A poison may not be detected in the body, owing to defective methods, smallness of the dose required to cause death, or to its ejection by vomiting or its elimination by the excretions.
  5. Conduct of Suspected Persons.—A prisoner may be proved to have purchased poison, to have made a study of the properties and effects of poison, to have concocted medicines or prepared food for the deceased, to have made himself the sole attendant of the deceased, to have placed obstacles in the way of obtaining proper medical assistance, or to have removed substances which might have been examined.

V.—SYMPTOMS AND POST-MORTEM APPEARANCES OF DIFFERENT CLASSES OF POISONS

Whilst recognizing the fact that toxic agents cannot be accurately classified, the following grouping may for descriptive purposes be admitted with the view of saving needless repetition: