II. 
ox THE EXTIXCTION OF SPECIES BY THE 
IXDIKECT ACTS OF MAX, 
Bv Thomas Southwell, E.Z.S. 
Read 26th Oct., 1880. 
At tlio Annual Meeting of our Society I asked your attention to 
some observations on “The extinction of native races, brought about 
in recent times by the advent of civilized man in countries and 
places where he was before unknown.” On that occasion I 
conlined myself to such animals, as it apjDcarcd to me, were either 
exterminated by the direct acts of man, or are so rapidly decreasing 
in numbers as to render it probable tliat their S2)eedy extermination 
from the same causes may be looked for. I now j^nrposc to sjjcak 
of the like effects arising from the indirect acts of man, and more 
particularly from the introduction of animals (generally, but not 
necessaril}L rapacious ones) before unknowu, with a glance at some 
ot the cliangcs in the vegetable productions of A^arious parts of the 
Avorld, Avhich have resulted from similar disturbing inlluences. 
In attempting to give some account of these changes, Avhicli 
must of necessity be A'ery superficial, I might almost Avrite a 
treatise on the “Acclimatization of Species,” as it. is almost 
entirely to this pernicious practice that the evil is due; for, 
boAvever fatal to the inhabitants of a country may have been the 
efi'ects of bush-burning and timber-felling, I tliink it Avill be found 
that the introduction of animals and plants of a more specialized 
type, and, therefore, better fitted to carry on the struggle for 
existence than the races Avith Avhich they are brought into contact, 
has far exceeded the evils to be attributed to the former causes, 
and, in fact, it is not improbable that the mischief may in many 
cases have already been effected before the destruction of the forests 
commenced. As Avill be seen, liOAVcvcr, the transport of some 
species has been the result of accident rather than of intention. 
