PRESIDENTIAL ADDRESS. 61 



It is our duty iu either describing plants or publishing 

 notes concerning them, to publish any information of our 

 senses which is not clearly explicable. A case in point is 

 the odours of grasses to which I have drawn attention in 

 another place. 1 Perhaps cyanogenesis may be indicated 

 in some instances and a saponin in another. The botanist 

 can in such cases act as a pointer to the phyto-chemist 

 and the vegetable physiologist. 



In referring to odours of plants the line of demarcation 

 between sweet and disagreeable odours is oue which is not 

 clearly understood at present. The odours of EragrosUs 2 

 and Dysoxylon 3 are cases in point. 



Then varying degrees of what we know as ''bitterness" 

 should incite us to enquire as to the cause of such a property. 



The rubbing of a Eucalyptus or other leaf in the warm 

 hand as we pass through the bush, is an experiment of great 

 value in the hands of an observant man, — it is qualitative 

 in that it is a guide to the kind of essential oil in the plant, 

 and obviously quantitative in addition. Indeed an observant 

 man can, from experiments of this kind, say whether a 

 particular species should be tested for oil on a commercial 

 scale, or whether it will only produce small quantities, 

 regardless of cost, for scientific investigation. 



It would be the duty of a chemist attached to the physio- 

 logical laboratory in a botanic garden, to work systemati- 

 cally through the fresh or other material than can best be 

 obtained in such an establishment, chiefly applying quali- 

 tative tests, and leaving the quantitative work in most 

 instances to other chemists. No chemist who desired an 

 indication as to work for research need go away unsatisfied, 

 and in many cases material could be offered to him. It 

 however should be borne in mind that no plant is grown in 



1 Agric. Gasette, N.S W., 1912, (not yet published). 

 2 hoc. cit. 3 Forest Flora of IV.S.W., iii, 100. 



