208 
Acclimatisation. 
[April, 
together as house-flies, such as Mtisca domestica and Stomoxys 
calcitrans, “ have been imported into Chili, Australia, an 
New Zealand, where they were not indigenous, and wheie, 
it may be added, they are multiplying and growing iorrm- 
dable. The United States, even, seem to have been 
originally free from this plague. Hence it may De safely 
asserted that the aboriginal plants and animals of any 
country are by no means necessarily confined to that country, 
but that when intentionally or accidentally transported else- 
where they may flourish as well as — or even bettei than 
at home. ... , 
This latter portion of the proposition is merely an exten- 
sion of the observation of Dean Herbert, that we do not o 
necessity find plants growing in the soil or the station bes 
suited for their wants, but often where they are most secuie 
from the rivalry of encroaching species. 
I am next compelled to bring forward a consideration 
which will, 1 fear, lay me open to the charge of pessimism. 
There is scarcely any instance where a beautilul, a useful, 
or even a harmless plant or animal has been accidentally 
introduced, and where, if imported purposely, it has been 
able to dispense afterwards with man’s care and protection. 
On the contrary, the species most commonly and easily 
naturalised are weeds and vermin. This is a striking and 
a most distressing fact, shadowed forth in the primal curse,: 
“ Thorns also and thistles shall it bring forth unto thee. 
I may be asked for a definition of “weeds” and ol 
“ vermin.” These names are applied to organisms which 
satisfy neither our aesthetic nor our economic wants, and 
which are often actively injurious to our persons or to our 
property. Decided beauty may make us overlook useless- 
ness, and manifest utility makes us condone ugliness. 13ut 
the iniurious plant and the harmful animal, even it beauti- 
ful _ a very rare case,— are invariably written in the Index 
epurgatorius. There is, of course, scope for some little dif- 
ference of opinion as to what species are ugly and which 
are hurtful, but these dissidences do not affect the geneial 
^ We^have to look yet a little further. To the very essence 
of a weed or a vermin belong great reproductive power, 
tenacity of life, and adaptability to varying conditions, but 
for these last attributes ugliness and uselessness would 
escape notice, and positive harmfulness would be practically 
neutralised. Now the misfortune is that beautilul or useful 
organisms rarely possess these features in any marked ex- 
tent, whilst ugly and useless or pernicious species manliest 
