napellus, sinense, tauricum, uncinatum, and ferox, possess it intensely, A. schleicheri and nasutum feebly, A. neomontanum very feebly; all of which are therefore probably poisonous, in proportion to the intensity of their taste. A. ferox, well known as a deadly poison in the East, and undoubtedly the most virulent of all the species, produces by far the most intense and persistent effect on the mouth of all the species I have had an opportunity of examining. Those which do not produce it at all, at least in this climate, are A. paniculatum, lasiostomum, vulparia, variegatum, nitidum, pyrenaïcum, and ochroleucum. It would be premature to say that all these species are inert; but I suspect they are: and, at all events, I have ascertained that the leaves of A. paniculatum, although the officinal species recognised in the London Pharmacopœia, are quite inactive in this climate; and Dr. Fleming has found the root inert in medicinal doses of considerable magnitude.
The properties of monkshood have been traced by Geiger and Hesse to a peculiar alkaloid, named aconitina: which is white, pulverulent, fusible, not volatile, soluble in ether and alcohol, sparingly so in water, and capable of forming crystallizable salts with acids. It produces most intensely the peculiar impression caused by the plant on the mouth, tongue, and lips; and it is a poison of tremendous activity, probably indeed the most subtle of all known poisons. Although not a volatile principle, it has been supposed peculiarly liable to decomposition by heat, at least in its natural state of combination in the plant or its pharmaceutic preparations. This opinion is founded on the uncertainty of the medicinal action of the common extract of the shops, and on the results of experiments on animals by Orfila.[1] In one experiment he found that half an ounce of the extract of the Parisian shops had no effect at all on a dog, while a quarter of an ounce killed another within two hours. Careless preparation may account for such differences; but at the same time an error in choosing the species of plant is an equally probable explanation. The properties of monkshood appear to me to resist a heat of 212°, either in drying the plant or in preparing an extract from it.
The medico-legal chemistry of monkshood has not been studied. If any of the suspected matter be obtained in a pure state, its best character is its remarkable taste; to which I have found nothing exactly similar in the numerous trials I have made with other narcotic and acrid plants. A complex substance, such as the contents of the stomach, or vomited matter, should be evaporated over the vapour-bath to the consistence of thin syrup, and agitated with absolute alcohol. The filtered alcoholic solution being then evaporated, the extract may be subjected to the sense of taste.
Action.—The action of monkshood is a subject of great interest, but has hitherto been much misunderstood. Sir B. Brodie, who was the first to examine it in recent times, found that the leading phenomena in animals, were staggering, excessive weakness, slow
- ↑ Toxicologie Gén. 1827, ii. 211.
