xl. ABSTRACT OF PROCEEDINGS. 



Discussion of Mr. G. H. Knibbs' paper on "The Theory of City 

 Design." then took place, the following members contributing 

 thereto, viz., Messrs. H. G. McKinney, H. E. Ross, Norman Selfe, 

 J. H. Maiden, His Honour Judge Docker, Professor Warren, 

 Messrs. James Taylor, and Henry Deane. In view of the further 

 business for the meeting Mr. Knibbs but briefly replied. 



THE FOLLOWING PAPER WAS READ : 



1. "On the relation between leaf venation and the presence of 

 certain chemical constituents in the oils of the Eucalypts," 

 by R. T. Baker, f.l.s., Curator, and Henry G. Smith, f.c.s., 

 Assistant Curator, Technological Museum, Sydney. 



In this paper the authors show that there exists a marked 

 agreement between the venation of Eucalypts leaves and the 

 characteristic constituents in their oils. The venation shown by 

 the leaves of the "Blood woods" E. corymbosa, E. trachyphloia, etc. 

 is indicative of a predominance of pinene in the oils, and an 

 absence of phellandrene. It is this end of the Eucalyptus series 

 that is more closely associated with the Angophoras, because the 

 venation of the leaves is similar, and the chemical constituents in 

 agreement. As the series descends through such species as E. 

 botryoides, E. saligna, etc., we reach those Eucalypts whose 

 principal oil constituents are pinene and eucalyptol, the latter 

 constituent increasing in amount until such excellent eucalyptol 

 oils as those of E. globulus, E. Smithii, E. longifolia, etc. are 

 reached. The venation of the leaves of these species is similar, is 

 more open, the individual lateral veins have become more distinct, 

 and with the bending of the marginal vein, commencing to form 

 the looping so characteristic of the phellandrene-peppermint group, 

 the species of which include those of E. dives, E. radiata, E. 

 amygdalina, E. Sieberiana, etc. The principal constituent in 

 these oils is phellandrene, and at the extreme end this constituent 

 is present in such abundance as to exclude, almost entirely, the 

 eucalyptol, The pinene which was such a prominent constituent 

 in the oils of the earlier members of the series, is only present in 

 the oils of this group in minute quantities. The looping appear- 



