of the canoes were never heard of; but the
other was drifted from one uninhabited island to another, at each of
which the voyagers obtained a few provisions; and at length, after
having wandered for a distance of 600 miles, they were found and carried
to their home in the Blossom.[945]

Mr. Crawfurd informs me that there are several well-authenticated
accounts of canoes having been drifted from Sumatra to Madagascar, and
by such causes a portion of the Malayan language, with some useful
plants, have been transferred to that island, which is principally
peopled by negroes.

The space traversed in some of these instances was so great, that
similar accidents might suffice to transport canoes from various parts
of Africa to the shores of South America, or from Spain to the Azores,
and thence to North America; so that man, even in a rude state of
society, is liable to be scattered involuntarily by the winds and waves
over the globe, in a manner singularly analogous to that in which many
plants and animals are diffused. We ought not, then, to wonder, that
during the ages required for some tribes of the human race to attain
that advanced stage of civilization which empowers the navigator to
cross the ocean in all directions with security, the whole earth should
have become the abode of rude tribes of hunters and fishers. Were the
whole of mankind now cut off, with the exception of one family,
inhabiting the old or new continent, or Australia, or even some coral
islet of the Pacific, we might expect their descendants, though they
should never become more enlightened than the South Sea Islanders or the
Esquimaux, to spread in the course of ages over the whole earth,
diffused partly by the tendency of population to increase, in a limited
district, beyond the means of subsistence, and partly by the accidental
drifting of canoes by tides and currents to distant shores.

_Involuntary Influence of Man in diffusing Animals and Plants._

Many of the general remarks which have been made respecting the
influence of man in spreading or in checking the diffusion of plants
apply equally to his relations with the animal kingdom. On a future
occasion I shall be led to speak of the instrumentality of our species
in naturalizing useful animals and plants in new regions, when
explaining my views of the effects which the spreading and increase of
certain species exert in the extirpation of others. At present I shall
confine myself to a few