263 



PROCEEDINGS 



OF THE 



ROYAL SOCIETY OF EDINBURGH. 



VOL. II. 1850. No. 36. 



Monday, January 21, 1850. 



Dr CHRISTISON, Y.P., in the Chair. 



The following Communications were read : — 



I. On the Gamboge Tree of Siam. By Dr Christison. 



Although Gamboge has been known in European commerce for 

 nearly two centuries and a half, and its applications in the arts have 

 been extended in recent times, the tree which produces it is still 

 unknown to botanists. 



The late Dr Graham, in 1836, was the first to describe accurately 

 a species of Garcinia, which inhabits Ceylon, and which is well 

 known there to produce a sort of Gamboge, not, however, known in 

 the commerce of Eui*ope. Resting on a pecuharity in the structure 

 of the anthers, which are circumscissile, or open transversely by the 

 separation of a lid on the summit, he constituted a new genus for 

 this plant, and called it Hehradendron camhogioides. At the same 

 period the Author examined the properties of this Gamboge, and 

 found that it possesses the purgative action of the commercial drug 

 in full intensity, and that the two kinds agree closely also, though 

 not absolutely, in chemical constitution. 



At an eai-lier period Dr Roxburgh described, in his " Flora In- 

 dica," another species of Garcinia, under the name of Garcinia pic- 

 toria, which inhabits the hills of Western Mysore, and wliich also 



VOL. II. 2 A 



