294 Proceedings of section b. 



TJie exudation of P. bicolor is, therefore, a gum-resin 

 whose resin holds an essential oil incorporated with it, and 

 its composition is analogous to that of myrrh, which likewise 

 contains about 40 per cent, of gum. 



It will be convenient to institute a brief comparison 

 between the gum -resins of P. bicolor and P. undulaLum 

 after the latter has been dealt with. 



Pittosporum undulatum, Vent. : " Cheesewood." 

 Found in all the Colonies except South and Western Australia. 



It appears that trees of this species require to be injured, 

 as sound, uninjured trees have not been observed to yield 

 gum-resin. This species is very liable to be attacked by 

 borers, which cause an exudation of 7*esin, but even in sound 

 trees the fruits are sticky fi-om presence of gum-resin. This 

 substance has a powerful and, to my mind, if not too abun- 

 dant (when it is apt to create nausea), a delicious odour of a 

 turpentiny character, which somewhat i-esembles that of oil 

 of cubebs, but it is quite per se. In the mouth it sticks to 

 the teeth, softening very readily. It tastes powerfully 

 aromatic, and slightly burns the tongue. It is of an amber 

 colour when freshly exuded, but darkens with age. It is 

 more or less liquid. 



A correspondent stated that, having a dog badly wounded, 

 he ajjplied this resin, " on account of its aromatic smell," 

 when the wound healed " with amazing quickness in a few 

 days." 



2"518 grams of the exudation from P. undulatum. taken 

 and digested in light petroleum for eight days, when 42-960 

 per cent, of resin and essential oil were dissolved out. The 

 solution was heated in an air bath at 1 10° C, till a constant 

 weight was obtained, when 7'599 per cent, of esssential oil 

 w^as driven off. The remaining resin (35'361 " /o) was very 

 brittle, almost colourless, and very hard. Water was not 

 required to facilitate the removal of the essential oil as appears 

 necessary in the case of P. hicolor. 



Of the residue, 33*r2 per cent, of resin was dissolved by 

 ether. This is also a bright, clear, hard, brittle resin, and 

 slightly yellowish in colour. 



Alcohol dissolves 1'639 per cent, of this residue, removing 

 a resin much resembling that dissolved by ether in colour 

 and general appearance, although quite insoluble in that 

 solvent. Total resins dissolved, 77-719 per cent. 



