2. To stop the action of the poison if it cannot be readily and immediately removed.—The means whereby this is effected is ordinarily the administration of an antidote. As no universal antidote is known, the treatment will of course vary with the substance taken. This will be fully explained when speaking of each particular poison.
An antidote, according to Orfila, should possess the following properties:—It should be capable of being taken in a large dose without danger; it should act upon the poison, whether liquid or solid, at a temperature equal to or below that of the body; its action should be quick; it should be capable of combining with the poison, though shielded by the gastric juice, mucus, bile, or other substances contained in the stomach; and lastly, it should deprive the poison of its deleterious properties.
Antidotes mostly operate by forming harmless chemical combinations, or by producing insoluble compounds, and thus preventing or delaying absorption. In most cases they have no effect upon the constitution; but some may be looked upon as a kind of counter-poison. Thus, the antagonistic action of opium and belladonna seems fairly made out, and we might perhaps include under this head chloroform, as in some degree, an antidote to strychnia.
Dr. Garrod has described a series of experiments in which he employed purified animal charcoal as an antidote. Dogs, rabbits, and guinea-pigs were the animals experimented on; while the poisons consisted of large doses of opium, belladonna, aconite, nux vomica, arsenic, and other drugs. They were given without mischief when sufficient animal charcoal was administered simultaneously, or, in some instances, before the peculiar effects of the destructive drug were developed. This substance seems to act in a great measure mechanically, but it has also a power of absorbing alkaloids which may render it useful. Such substances as magnesia and gruel are sometimes given with the view of protecting the walls of the stomach, with doubtful benefit.
3. To remedy the mischief done, and obviate the tendency to death.—Unfortunately, in a great number of instances, too long an interval has elapsed between the exhibition of the poison and the time when the first-mentioned indications can be fully carried into effect; for, as before implied, if absorption has taken place, direct antidotes will be of little avail.
Our object must then be to palliate the symptoms as they arise, as well as to neutralize the effects of the poison on the constitution, by remedies of an opposite character. Thus in poisoning by depressing agents and narcotics, or such as destroy the nervous force, all lowering measures must be avoided, and agents used which will exert a contrary effect, as stimulants, cold effusion, galvanism &c. The shock to the nervous system must also be taken account, and appropriate remedies employed to aid it in rallying.
Thus direct injection of liquid ammonia into the veins has been found successful in the treatment of snake bite in Australia, by Professor Halford and others.
Claude Bernard has shown the importance of particularly attending to the way in which the poison destroys life. For example, curare paralyzes the motor nerves, puts a stop to all motion, suspends respiration, and so brings on suffocation; yet by keeping up artificial respiration for a sufficient length of time, life may be preserved till the poison is eliminated and the danger over. Strychnia attacks the sensitive portion of the nervous system; but if the external excitement, which perpetually provokes reflex action and thereby brings on fatal convulsions, be guarded against, recovery may ensue. A frog, poisoned by strychnia, rapidly dies if frequently excited; whereas left perfectly quiet under a bell-glass, it will, cæteris paribus, recover.
Lastly, we must endeavor to promote the elimination of the poison from the body, by exciting the excreting functions; for which purpose, in poisoning by arsenic, after the stomach has been well emptied, Orfila has proposed the employment of diuretics, because it has been found that this poison, like most others, is carried off in large quantities by the urine.