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:



1. =Corrosives.=--Characterized by their destructive action on tissues

with which they come in contact. The principal inorganic corrosives are

the mineral acids, the caustic alkalies, and their carbonates; the

organic are carbolic acid, strong solutions of oxalic acid, and acetic

acid.



Symptoms.--Burning pain in mouth, throat, and gullet, strong acid,

metallic or alkaline taste; retching and vomiting, the discharged

matters containing shreds of mucus, blood, and the lining membrane of

the passages. Inside of mouth corroded. There are also dysphagia,

thirst, dyspnoea, small and frequent pulse, anxious expression, shock.

Death may result from shock, destruction of the parts--e.g.,

perforation of stomach or duodenum, suffocation; or some weeks

subsequently death may be due to cicatricial contraction of the gullet,

stomach, or pylorus.



Post-Mortem Appearances.--Those of corrosion, with corrugation from

strong contraction of muscular fibres, and followed by inflammation and

its consequences. The mouth, gullet, and stomach, and in some cases the

intestines, may be white, yellow, or brown, shrivelled and corroded. The

corrosions may be small, or may extend over a very large surface.

Sometimes considerable portions of the lining membrane of the gullet or

stomach may be discharged by vomiting or by stool. Beyond the corroded

parts the textures are acutely inflamed. The stomach is filled with a

yellow, brown, or black gelatinous liquid or black blood, and may in

rare cases be perforated.



2. =Irritants.=--These are substances which inflame parts to which they

are applied. The class includes mineral, animal, and vegetable

substances, and contains a larger number of poisons than all the other

classes together. Irritants may be divided into two groups: (1) Those

which destroy life by the irritation they set up in the parts to which

they are applied; (2) those which add to local irritation peculiar or

specific remote effects. The first group includes the principal

vegetable irritants, some alkaline salts, some metallic poisons, etc.;

and the second comprises the metallic irritants, the metalloids

(phosphorus and iodine), and one animal substance, cantharides.



Symptoms.--Burning pain and constriction in throat and gullet, pain

and tenderness of stomach and bowels, intense thirst, nausea, vomiting,

purging and tenesmus, with bloody stools, dysuria, cold skin, and feeble

and irregular pulse. The vomit consists at first of the food, then it

becomes bile-stained, and later dark coffee-grounds in appearance, due

to extravasation of blood from the over-distended vessels in the gastric

mucous membrane. Death may occur from shock, convulsions, collapse,

exhaustion, or from starvation on account of chronic inflammation of the

gastro-intestinal mucous membrane.



Post-Mortem Appearances.--Those of inflammation and its consequences.

Coats of stomach, fauces, gullet, and duodenum, may be thickened,

black, ulcerated, gangrenous, or sloughing. Vessels filled with dark

blood ramify over the surface. Acute inflammation is often found in the

small intestines, with ulceration and softening of mucous membrane. The

rectum is frequently the seat of marked ulceration.



3. =Poisons Acting on the Brain.=--Three classes: The opium group,

producing sleep; the belladonna group, producing delirium and illusions;

and the alcohol group, causing exhilaration, followed by delirium or

sleep.



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, thebaïne.

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).





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