PRESroENT's ADDRESS — SECTION B. 79 



possible, and where not possible the chief consideration has been to 

 get rid of it at all costs. It is true that there are now sewage works 

 in many parts of the world, and treated sewage has been shown to be 

 a satisfactory manure for many crops. But an immense waste of 

 valuable nitrogenous material is going on ; and while it would be 

 going too far to expect that the whole of the nitrogen in sewage will 

 ever be available for plants, one must confess that the amount available 

 at present is far below the attainable, and it is hoped that the chemical 

 engineer and the bacteriologist will yet, be able to devise an economical 

 treatment of sewage for towns, so that it may become the rule and 

 not the exception for every city to utilize its sewage for agricultural 

 purposes. If one cojisiders the present position of the world's supply 

 of nitrogen, there does not seem to me to be the same cause for alarm 

 as when Sir W. Crookes first stirred up scientists and the general public 

 to the situation. I believe we can now say that the supply of artificial 

 nitrogen compounds will be forthcoming when it is necessary. 



There are many problems which specially present themselves to 

 the chemist in Australia besides those connected with agricultural 

 pursuits. One of the largest and most difficult of these is an investi- 

 gation of the chemical composition of substances contained in or easily 

 derivable from the native trees and shrubs of the continent. 



While this subject has been touched by many, it has been opened 

 up to a greater extent by Messrs. R. T. Baker and H. G. Smith, of 

 Sydney, than any other investigators. 



Labouring for love of their work, without any special pecuniary 

 reward or encouragement, and oftentimes working under great 

 difficulties, these investigators have after many years of work thoroughly 

 examined the substances in most of the eucalypts and pines of Australia . 

 Now that the work is bea,ring fruit in the sense that through applying 

 the knowledge gained money may be made, the importance of the work 

 is being indirectly recognised by the public. 



The researches of Baker and Smith have shown that valuable 

 commercial substances are contained in many of the bush trees and 

 shrubs of Australia. The leaves, the bark, the exudation after making 

 an incision in the trunk or the wood itself may each or all be of value. 

 Utihzation of the leaves and young stems of the trees does not kill 

 the trees, but results in another crop of young shoots which are ready 

 for collection in many cases after another two years. Thus, when the 

 leaves may be made a source of profit the total wealth furnished by ? 

 tree is almost inexhaustible. 



The indiscriminate clearing of bush trees is already recognised 

 by many as a mistake, on account of the loss of timber, loss of shade, 

 and alteration of climate or of local effects of climate, but we now realize 

 that in many cases another asset is lost in the matter of an annual or 

 biennial crop of leaves. 



