152 



different kinds of Gamboge. It is well known that Linnaeus re- 

 ferred gamboge to the Garcinia cambogia, Willd. ; and others have 

 supposed that a kind of gamboge is also produced by the Xantho- 

 chymus pictorius. Both are natives of Ceylon, M'here, as appears 

 from the former investigations of the author, a substance is pro- 

 duced almost or absolutely identical with Siam gamboge. It ap- 

 peared, however, from the inquiries of Dr Graham, read before 

 the Society last session, that this Ceylon gamboge is produced by 

 an nndescribed species of tree, and not by either of the species 

 jnst mentioned. 



Dr Christison has now been enabled to add to this investigation 

 an account of the composition and properties of the concrete juices 

 of the Garcinia cambogia and Xanthochymns pictorius, which were 

 transmitted from Colombo by Mrs Colonel AValker. These con- 

 crete juices, which were sent attached to the barks that produced 

 them, differ from gamboge in having a much paler yellow colour, 

 and not being at all emulsive. That of the Garcinia cambogia also 

 differs in not being at all purgative, at least in doses three or four 

 times as great as the customary doses of gamboge ; and its colour- 

 ing resin possesses only a tenth part of the intensity of the colour 

 of true gamboge resin. Farther, both the concrete juices in ques- 

 tion differ essentially from gamboge in composition, in so far as both 

 contain proportionally less gum, and one of them contains some vo- 

 latile oil. Their composition was found to be as follows : — 



Resin .... 66.0 76.5 



Arabin .... 14w0 17.6 



Volatile oil . . . 12.0 0.0 



Accidental fibre . . 5.0 5.9 



I^oss, probablj volatile oil, 3-0 0.0 



100.0 100.0 



The author farther announced that Dr Graham had been lately 

 enabled to determine, with the assistance of Dr Brown, certain 

 points which he had left undecided in his paper of the previous ses- 

 sion, on the botanical source of true Ceylon gamboge. It now ap- 

 pears, that the specimen from which Murray of Gottingen esta- 

 blished his Stalagmitis gambogioides, and which is still preserved in 

 the Banksian Herbarium, is in reality a patched one, consisting, 

 probably, of the Xanthochymus ovalifolius and of the true plant. 

 Dr Graham has therefore felt no hesitation in attaching to Mrs 

 Colonel Walker's specimens a new generic name, derived from thte 



