SPOTTED HEMLOCK. Umbelliferae. It is a native of Europe, but is naturalized in the United States.
The active principle is conia, a yellowish oily-looking transparent fluid, lighter than water, of an acrid, nauseous, tobacco-like taste. It smells like tobacco and mice. It is very volatile, slightly soluble in water,—less so in warm water than in cold water,—readily soluble in alcohol, ether and oils. It is alkaline. Its combinations with acids do not easily crystallize, and are very soluble and poisonous.
It was known in ancient times, but has not until recently been used as an internal medicine. It was a means of killing political offenders. Socrates drank it, and his death is thus described:
After swallowing the poisoned cup he walked about for a short time, as directed by his executioner ; when he felt a heaviness in his limbs he lay down on his back; his legs and feet first lost their sensibility and became stiff and cold; and this state gradually extended upward to the heart, when he died convulsed." This is the brief account given by Paul of Aegeria. Xenophon relates that he continued to talk with his friends and disciples both while he walked and after he lay down. This gives us evidence that his mind retained its normal condition after the limbs had refused to fulfill their functions.
Conium that grows in southern latitudes is thought to be more powerful than that which grows in northern climates. It should not be subjected to heat, because the active principle is volatile; hence the extract is often inert. The most active preparation is the juice, succus conii; and this is almost identical with the homeopathic tincture.
Conium was recommended by the ancients as an anodyne for pains, and as useful in erysipelas and in phagedenic ulcers. Dioscorides recommended the bruised plant to be applied upon the genitals to remedy nocturnal pollutions, and upon the breasts of girls to prevent their development. Pliny and Avicenna recommend poultices of Conium and corn-plaster to remove tumors of the breasts and testes, and to repress the secretion of milk.
In modern times it has been applied for the same purposes ; and at one time it gained a high though undeserved reputation for the cure of cancer.
It is remarkable that while this substance, or its active principle, is one of the most active and rapid poisons, yet some animals, as the goat, sheep and horse, eat the plant with impunity.
The following case of poisoning from eating a Conium salad illustrates its action in large doses: In this man was first noticed weakness of the legs, so that his gait was staggering. As the weakness increased, he tottered as if drunk; and his arms began to be similarly affected. Loss of all voluntary motion followed, and he was unable to swallow. Lastly, the muscles of respiration were affected slowly by paralysis, and he died of asphyxia. Up to the time of death his intelligence was unimpaired, but his sight was destroyed though his hearing remained. There was no decided spasmodic affection of the muscles.
Gradual paralysis, then, of the voluntary muscles seems to be the effect of Conium ; first the lower, then the upper extremities, then the muscles of the trunk, and finally those of respiration. Let us inquire, How is this paralysis produced ? It may be by affections of the muscles themselves, or of the brain and cord, the centres of action, or of the nerves, the conveyors of stimulus to act. Is it due to changes produced in the muscles by Conium ? Probably not, because muscles taken from an animal completely paralyzed by Conium act energetically under a galvanic current, and do not act when the current is passed through the nerves supplying the muscles; but only when the current is passed through the muscular substance itself.
It cannot be that the spinal cord is affected, because if the artery and vein of one limb be ligatured, and the animal then paralyzed by Conium, the limb thus protected is moved energetically, as in health. Neither can its action be on the brain, because in this case the poisoned blood passed as freely to the brain as to the cord ; nor was intelligence impaired. It must, then, affect the motor and the periphery sooner than the trunk of the nerve.
The sensory nerves do not appear to be affected.
Dr. John Harley, of London, has recently published a work containing provings upon the healthy subject, of Conium and some other drugs. He says:
"The first effect of Conium is a depression of the motor function; and its last is the complete obliteration of all muscular motion derived from the cerebro-spinal-motor tract.
After taking 3iij of the succus conii, I set out walking, and three-quarters of an hour after the dose I felt a heavy, clogging sensation in my heels, a distinct impairment of the motor power. I felt that the go was taken out of me. Vision was good for fixed objects, but accommodation was sluggish. Continued exertion removed these symptoms. The mind was not affected.
Dr. Harley sums up the action of Conium as follows: "It exerts its power chiefly, if not exclusively, upon the motor centres within the cranium; and of these the corpora striata are the parts chiefly affected. The sensory part of the nervous system is not affected. From this view of the physiological action of Conium Dr. Harley concludes that in selecting Conium as a remedy for nervous diseases we must be guided by that simple view of its physiological action which is stated above, and we must ask 'is there irritation direct or reflex of the motor centres?' If so, we hope for good from Conium.
Harley, therefore, recommends Conium in convulsions, chorea and muscular tremor, in pertussis and spasm of the oesophagus and stomach, in spasm of the glottis; in paraplegia and concussion of the spine; in exhaustion of the sexual organs; also in ophthalmia, especially the strumous variety, which he ascribes to spasm of the orbicularis and corrugator supercilii. He regards it as a palliative in cancer, in that it allays muscular spasm, and thus mitigates pain.