But the subject was afterwards taken up with success by Geiger, who obtained from the plant a volatile, oleaginous alkaloid, which possesses great energy as a poison.[1] Mr. Morries-Stirling procured from hemlock by destructive distillation an empyreumatic oil similar in properties to those of hyoscyamus, stramonium and tobacco, but producing in animals a state of pure coma.[2]
The effects of hemlock on the animal system have been variously described by different observers. Sometimes they have appeared to be purely soporific like those of opium; at other times they have resembled the effects of belladonna and thorn-apple; and in the lower animals they are quite different, as I have witnessed them, from what they have been described to be in man,—the phenomena being simply those of asphyxia from paralysis of the muscles, without material convulsions and without insensibility. Its irritant action is not well established.
Orfila observed that an ounce of the extract of the leaves killed a dog in forty-five minutes when swallowed, ninety grains killed another through a wound in an hour and a half, and twenty-eight grains another through a vein in two minutes. It therefore acts by entering the blood-vessels. The extract is a very uncertain preparation; the reason of which is, that the alkaloid conia is very easily decomposed in its natural state of mixture by heat or age, being converted into an inert resinoid matter,—that the dried leaves of hemlock contain scarcely any of it,—and that even an extract of the fresh leaves contains little, unless prepared with a gentle heat, yet speedily.[3] The symptoms remarked by Orfila were convulsions and insensibility; and in the dead body the blood of the left cavities of the heart was sometimes found arterial.—The result of my observations is quite at variance with this statement. In various experiments with a strong extract prepared from the green seeds with absolute alcohol, the only effect I could remark were palsy, first of the voluntary muscles, next of the chest, lastly of the diaphragm,—asphyxia in short from paralysis, without insensibility, and with slight occasional twitches only of the limbs, and the heart was always found contracting vigorously for a long time after death. Thirty grains of a soft extract introduced between the skin and muscles of the back killed a rabbit in five minutes, and a five months' puppy in twenty minutes.[4]
The root is much less energetic than is represented by some authors, and probably varies in this respect at different seasons. I have found that four ounces and a half of juice, the produce of twelve ounces of roots collected in November, had no effect on a dog when secured in its stomach by a ligature on the gullet; and that four ounces obtained from ten ounces of roots in the middle of June, when the plant was coming into flower, merely caused diarrhœa and languor. Orfila had previously observed that three pounds
