TROCEEDINGS 



OF THE 



ROYAL SOCIETY OF EDINBURGH. 



1844. No. 23. 



Monday, 4th December 1843. 

 Sir THOMAS BRISBANE, President, in the Chair. 



The following communication was read : — 



On the Influence of various Circumstances in Vegetation upon 

 the activity of Plants. Part II. The Umbelliferous 

 Narcotics. By Dv Christison. 



In the Fu-st Part of this inquiry, the author gave an account, in 

 1840, of some observations made by him, as to the influeuce of 

 season on the activity of the acrid jjlants of the natural family 

 Rammcuhicece, and of the narcotics belonging to the famil}"^ Dru- 

 paceie.* In the Second Part now laid before the Society, he pro- 

 ceeded to relate a scries of experiments instituted by him with the 

 view of determining the influence of season on the activity of the 

 poisonous narcotic ])lants of the family Umhellifera;. 



Th(! plants belonging to this family are for the most part aromatic 

 and stimidant, and destitute of poisonous projierties. In four species 

 only have narcotic properties been unequivocally recognised, viz., 

 Conimn maodatam, (Emaithe crocatu, Cicuta virosa, and ^thu--'n 

 CijiKtpiam ; but these are universally held to be highly energetic. 



1. Coiiiaiti vutciihdum, Common Hemlock. — No' accurate infor- 

 mation is yet possessed as to the influence of season on the activity 

 of this species ; for all investigations on the subject are vitiated by 

 the uncertain strength of its preparations, and the ignorance which 

 prevailed till very lately as to the conditions required tor socurnig 



* See the Society's Proceedings, 1S40-41. 



