66 Royal Society of Edinburgh. 



but still green and juicy ; it then yields much more of the active 

 principle Conia than afterwards, when it is ripe and dry. The author 

 added, as a fact contrary to general belief, that he had found the ripe 

 seeds of hemlock and an alcoholic extract of the leaves to sustain no 

 diminution in energy by keeping, at all events for eight years. 



2. (Enanthe crocata. Dead-tongue. This species is universally 

 considered to be the most deadly of all the narcotic Umbelliferce. 

 Many instances of fatal poisoning with its roots have been published 

 during the last two centuries in the various periodicals of Europe. 

 It has repeatedly proved fatal in two hours ; and a portion no bigger 

 than a walnut has been thought adequate to occasion death. Fatal 

 accidents have occurred from it in England, France, Holland and 

 Corsica. The root would seem from these cases to be the most ac- 

 tive part ; but few observations are on record as to the effects of the 

 leaves, and none as to the fruit. The root appears from these cases 

 to be very active in all seasons, — at least at the beginning of January, 

 the end of March, the middle of April, June and August. 



The author proceeded to inquire carefully into the effect of season 

 upon this species, as it grows wild in the neighbourhood of Edin- 

 burgh ; but he was surprised to find that every part of the plant in 

 this locality is destitute of narcotic properties at all seasons. The 

 juice of a whole pound of the tubers, the part which has proved so 

 deadly elsewhere, had no effect when secured in the stomach of a 

 small dog, either at the end of October, when the tubers are plump 

 and perfect, but the plant not above ground, or in the month of June, 

 when it was coming into flower ; and an alcoholic extract of the 

 leaves, and that prepared from the ripe fruit, had no effect whatever 

 when introduced into the cellular tissue of the rabbit under the same 

 conditions in which the common hemlock acts so energetically. By 

 a comparative experiment he ascertained, that tubers collected near 

 Liverpool, where one of the accidents alluded to above happened in 

 1782, acted with considerable violence on the dog ; and he briefly no- 

 ticed some experiments made at his request by Dr. Pereira with the 

 (Enanthe of Wemich, showing that there also it is a powerful poison 

 to the lower animals. Climate seemed to the author to furnish the 

 only adequate explanation of these extraordinary differences ; yet the 

 plant grows in all parts of Scotland with great luxuriance. 



3. Cicuta virosa, Water-hemlock. This species has been also held 

 to be a deadly poison ever since an express treatise on its effects was 

 published by Wepfer in 1716; and repeated instances of its fatal 

 action have been observed since, and some of these very recently, in 

 Germany. The root is the only part which has given occasion to 

 accidents : it has proved fatal in two hours and a half. Neverthe- 

 less this plant too seems innocuous in Scotland, or nearly so, although, 

 like the last species, it grows with great luxuriance. The juice of a 

 pound of the roots, collected at the end of July while the plant was 

 in full flower, produced no narcotic symptoms ; and the only effects 

 observed, namely efforts to vomit, might have arisen from the opera- 

 tion which is necessary to secure the juice in the stomach. An al- 

 coholic extract of the leaves collected at the same time, and a simi- 



