_Symptoms._--Of the opium group, giddiness, headache, dimness of sight, contraction of the pupils, noises in the ears, drowsiness and confusion, passing into insensibility. Of the belladonna group, delirium, illusions of sight, dilated pupils, dry mouth, thirst, redness of skin, coma. Of the alcohol group, excitement of circulation and of cerebral functions, want of power of co-ordination and of muscular movement, double vision, mania, followed by profound sleep and coma. In the chronic form, delirium tremens. _Post-Mortem Appearances._--In the opium group, fulness of the sinuses and veins of the brain, with effusion of serum into the ventricles and beneath the membranes. In the belladonna group, nil. In the alcohol group, signs of inflammation, congestion of brain and membranes, fluidity of blood, long-continued rigor mortis. 4. =Poisons Acting on the Spinal Cord.=--Strychnine, brucine, thebaine. The leading symptom is tetanic spasm. 5. =Poisons Affecting the Heart.=--These kill by sudden shock, syncope, or collapse. They comprise prussic acid, dilute solution of oxalic acid and oxalates, aconite, digitalis, strophanthus, convallaria, and tobacco. 6. =Poisons Acting on the Lungs.=--These have for their type carbonic acid gas and coal gas. The fumes of ammonia are intensely irritating, and may give rise to laryngitis, bronchitis, and even pneumonia. Nitric acid fumes sometimes produce no serious symptoms for an hour or more, but there may then be coughing, difficulty of breathing, and tightness in the lower part of the throat, followed by capillary bronchitis (see p. 120). VI.--DUTY OF PRACTITIONER IN SUPPOSED CASE OF POISONING