The Chemistry and the Chemical Exploitation of Western 83 
Australian Plants. 
THE CHEMISTRY AND THE CHEMICAL EXPLOIT- 
ATION OF WESTERN AUSTRALIAN PLANTS 
PRESIDENTIAL ADDRESS, 1944. 
By E. M. Watson, Ph.I)., F.A.C.I. 
Delivered 11th July, 1941. 
CONTENTS. 
I. 
II. 
III. 
IV. 
V. 
VI. 
VII. 
VIII. 
IX. 
X. 
Introduction 
Essential Oils 
Family Santalaceae 
Family Myrtaceae 
Family Rutaceae ... 
Family Labia tae ... 
Family Coniferae ... 
Other Families 
Resins and Gums 
Tannins and Kinos 
Poison Plants — 
(a) Glycosides 
(i) Cyanogenetic Glycosides 
(ii) Saponins 
(iii) Other Toxic Glycosides 
(b) Alkaloids 
(c) Plants containing Nitrates ... 
(d) Photosensitising Plants 
(e) Fish Poisons ... 
(/) Miscellaneous Poisons 
Dyes and Colouring Matters ... 
Vitamins 
Medicinal Substances ... 
Wood Distillation 
Conclusion 
References 
Page 
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I. INTRODUCTION. 
Investigations of plants which are concerned directly or indirectly with 
their chemical composition are carried out by a variety of workers, including 
the chemist, plant physiologist, pharmacologist and agricultural chemist. 
In all such work, however specialised, collaboration with other scientific 
workers is essential, more particularly with the botanist, for incorrect identi- 
fication and naming of species invariably leads to much unnecessary labour. 
The researches of these workers are never directed towards painting a 
complete picture of the chemical composition of a plant, but are normally 
aimed at the isolation of a pure product of some scientific or medicinal 
value or the identification of some toxic substance. It is perhaps fortunate 
that this is so because of the difficulties which arise in such investigations. 
Such difficulties as are inherent in the variety, complexity and often 
the instability of the substances being handled, as well as the inaccuracy 
of many quantitative methods of analysis, are readily appreciated by the 
chemist. The magnitude of the work, however, is increased considerably 
by seasonal or even diurnal variation in the composition of plants, by 
variation in different parts of an individual plant and by variation due to 
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