200 A. G. HAMILTON. 
(3) that they also cause the water to drain more readily out of 
the soil and so render it drier. (4) That these effects being 
wrought, there is a very decided modification of the flora caused 
by deforesting, etc. 
(d) The effect of clearing on the fauna reacting on the flora. 
This is most decidedly a potent factor in the alteration of the 
native flora. For instance the destruction of shelter for the smaller 
marsupials leads them to flock to the forests left and become more 
abundant there. But their natural enemies being diminished by © 
the settlement of the country, the damage or benefit they cause to 
plants, directly or indirectly, will increase in those places and the 
flora will be modified accordingly. This subject, however, will be 
better considered in the second division of the paper. 
(e) The effect of checking bush fires on the vegetation. 
Previous to the settlement of Australia, bush fires undoubtedly 
played an important part in causing the changes—great or small 
—which then went on in the native flora. The aborigines were 
in the habit of setting fire to grassy tracts of country in order 
that the animals on which they lived might fall an easier prey to 
them ; and also in some cases, that the sweet fresh feed which 
springs up after a fire might attract kangaroos and wallabies. 
And doubtless too, they were as careless with their fires as white 
men so often are, and so accidental conflagrations took place. 
Either through lack of means or of inclination, they did not usually 
attempt to check the fires, which spread over vast tracts of country 
and in this way many plants must have been destroyed locally, 
and the flora so modified. And although at the present time (and 
still more in older days) the settlers burn off long dry grass so 
that their stock may have the fresh, young feed which so soon 
appears, yet on the whole it has been their aim to fight the fires 
and keep them down. 
Most of us know the great alteration which a bush fire makes 
in the tract burnt. The coarser undergrowth is destroyed and 
does not reappear for a long period of time, and the annual and 
