PROCEEDINGS OF SECTION B. 85 



Mr. Maiden divided these exudations into three groups, the " ruby," 

 the " gummy," and the " turbid." It was a useful classification at the 

 time, but subsequent work has shown it not to be sufficiently dis- 

 criminative, so that no good purpose can be served by retaining this 

 grouping. 



Chemical. 



Kinos from species whose exudations were first classified in the 

 "ruby group" commence to alter soon after exudation, so that 

 eventually they become much less soluble in both alcohol and Abater, 

 sometimes even forming a horny-like mass Avhich is then practically 

 insoluble. This tendency to alteration probably explains why it is 

 that the members of this class gelatinize so readily when dissolved 

 in alcohol, and for this reason the kinos belonging to the old " ruby 

 group " cannot be used commercially for tinctures. See paper on 

 this subject, Proc. Koy. Soc, N.S.W., August, 1904. 



Eucalyptus kinos do not contain gum in the correct sense of the 

 term, although precipitated by alcohol from an aqueous solution ; 

 and in a paper re.id before the Royal Society of New South Wales in 

 Jime, 1904, it was shown that the insoluble portions of these kinos in 

 alcohol is a glucoside, and it was named Emphloin. 



Those eucalyptus kinos which give turbid solutions in cold water 

 mostly contain either one or two crystallizable bodies — Eudesmin 

 and Aromadendrin — while some of them contain catechin, so that the 

 mere fact of turbidity does not convey much information. The kinos 

 of the Angophoras contain Aromadendrin, but not Eudesmin. The 

 exudation of Eucalyptus calophylla, a close ally of the Angophoras, 

 gives a turbid solution in water and contains Aromadendrin alone, 

 as do also most of the earHer members of the genus, or those more 

 closely associated with the Angophoras. As the genus evolved the 

 other constituent, Eudesmin, made its appearance and continued to 

 increase through the several species of this class, until the trees known 

 as '' boxes " {E. hemiphloia, E. Woollsiana, E. albens), were reached, 

 in the kinos of which Eudesmin is present in its maximum amount. 

 Although Eudesmin increases by easy stages in the kinos of the several 

 species of this class, yet it does not succeed in entirely replacing the 

 Aromadendrin, and in all the kinos, so far tested, in which Eudesmin 

 occurs, ii has been possible to detect Aromadendrin also, although 

 in some cases it was present only in traces. It has been shown pre- 

 viously that Aromadendrin does occur in the Idnos of some eucalyptus 

 species in which Eudesmin is quite absent, and as this is also the case 

 with the kinos of the Angophoras, it is reasonable to suppose that 

 Aromadendrin is the older of these two constituents. The colour 

 reactions with strong nitric and with concentrated sulphuric acids 

 are entirely opposite, and so delicate that traces only of Eudesmin 

 and Aromadendrin may be detected when present one with the other. 



