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THE AUSTRALIAN NATURALIST. 167 
lection also contains many indigenous kinds, and amongst 
these, I think, pride of place must be accorded to a beautiful 
example of the Freshwater Perch (Percalates fluviatilis) 
which, in a beautiful jar and surrounded by some exquisitely 
beautiful water plants, formed a veritable picture. 
It is to be hoped that Mr. Finckh and other members who 
keep aquaria, will lose no opportunity of obtaining photo- 
graphs of our indigenous fishes, taken in a living state 
through the aquarium walls. At present we are sadly lack- 
ing in these. 
At the conclusion of the visit, and when afternoon tea had 
been partaken of, the leader expressed the thanks of the 
members to Mr. and Mrs. Finckh for the kind way in which 
they had been entertained.—Davip G. STEAD. 
THE BALANCE OF NATURE. 
(By P. A. Gilbert.) 
‘upsetting the balance of nature’’ is the 
outcome of loose, unscientific reasoning, in relation to the 
displacement of some of our indigenous fauna, by exotic 
species such as rabbits, foxes, sparrows, etc., as well as other 
agencies, and is used in discussions on the preservation of 
animal life, more from ignorance of the fundamental laws of 
nature, than for any other cause. 
. We can see the incalculable harm to some of our indigenous 
animals, and their speedy retreat before the advance of the 
hardy exotic species now existant. But the marvellous 
fecundity of the latter and the wonderful rapidity of their 
increase, is but a transitional stage of their existence as 
survivors of the fittest—one species asserting its right to live 
where its competitor fails. 
The history of the past exemplifies the fact, that nature is 
inexorable in her preservation, or extirpation, of species 
according to their ability, or inability, to adapt themselves 
to the requirements of a changed environment; and the pre- 
sent and future will alike provide for those organisms that can 
best exist. 
‘THE expression ‘ 
In his primitive state it was necessary for the existence of 
man, that he should be gregarious in habit and small in num- 
ber; and the vast tracts of land which he now occupies in a 
civilised state, were once a part of the forests wherein he 
hunted in quest of his daily sustenance. In the transition of 
man from his primitiveness to a civilised state, he has left 
extinct, the contemporaries of his cave-dwelling days, the 
mammoth, woolly-haired rhinoceros, and many other authen- 
ticated animals. And here, may we ask, are the teeming mil- 
