120 Selections. [No. 7, new series, 



bid, and resembles a liquid in which finely-powdered cochineal 

 might be suspended. The complementary colour of red is not 

 therefore ' apparent by this means, but it becomes manifest when, 

 after agitation, a thin layer of liquid covers the upper sides of the 

 bottle. Then in whatever way we look at this thin layer, it ap- 

 pears of a beautiful green hue. 



This same green colour appears again and remains, when, after 

 having dissolved the wood-oil in alcohol, the solution is left to 

 spontaneous evaporation : one may then see towards the upper 

 part of the capsule, between the portions of green resin, white 

 starry tufts which are due to a peculiar principle, the future exa- 

 mination of which I leave to those who have a larger quantity of 

 the liquid at their disposal. As to the resin, it has acquired a 

 permanent green hue, which is also perceptible in the dry resin 

 which remains after the wood-oil has been boiled for a consider- 

 able time with water. This green colour, which is that also of 

 the beautiful Piney Resin {Vateria Indica L.) that was shown at 

 the Exhibition, establishes a point of relation between two pro- 

 ducts originating in trees belonging to the same family, that of the 

 Dipterocarpus. But there the resemblance stops, for the resin 

 of Vateria Indica is insoluble in alcohol, and very imperfectly so 

 in iEther, whilst the green resin of wood-oil is easily soluble in 

 either of these menstrua. Finally, the wood-oil of the Exhibition 

 behaves as copaiba, when treated with ammonia or calcined mag- 

 nesia. With one-sixteenth of calcined magnesia it very speedily 

 solidifies, and a mixture of it with ammonia becomes liquid, and 

 almost transparent, after an instant of opacity. 



I am far from concluding with Mr. Lowe that the two oleo- 

 resinous bodies (copaiba and wood-oil) are chemically identical ; 

 but as regards their employment in medicine, I think, as in the 

 case of bodies of analogous composition, such as turpentines and 

 balsams, liquid or solid, all their vegetable components may be of 

 use as a remedy for a catarrhal condition of the mucous mem- 

 branes. I may, remark in conclusion, that Mr. Hanbury's wood- 

 oil, and that from the Exhibition, have probably not been extract- 

 ed by a similar process. It seems to me that the former has been 

 obtained by the action of fire in the manner described by Rox- 



