“194 FOOT-NOTES TO EVOLUTION. 
colonized by immigrants from the mainland, the fact of 
‘uniformity of type is accounted for, but what of the 
difference of species? If the change of conditions from 
‘continent to island cause such great and permanent 
changes as to form new species from the old, why may 
not like changes take place on the mainlands as well as 
on the islands? Andif possible on the mainland of South 
America, what evidence have we that species are per- 
manent anywhere? May they not be constantly chang- 
ing? May not what we now consider as distinct species 
be only the present phase in the changing history of the 
series of forms which constitute the species ? 
The studies of these and many similar facts can lead 
but to one conclusion: 
These volcanic islands rose from the sea destitute of 
land life. They were settled by the waifs of wind and 
of storm, birds and insects blown from 
the shore by trade winds, lizards car- 
ried on drift logs and floating vegetation. Of these 
waifs few came perhaps in any one year, and few per- 
haps of those who came made the islands their home; 
yet, as the centuries passed on, suitable inhabitants 
were found. That this is not fancy we know, for we 
have the knowledge of many ways in which animals are 
carried from their natural homes. One example of this 
may be seen by those who have approached our eastern 
shores by sea in the face of a storm. Hosts of land 
birds—sparrows, warblers, chickadees, and even wood- 
peckers—are carried out by the wind, a few falling ex- 
hausted on the decks of ships, a few others falling on 
off-shore islands, like the Bermudas, the remainder 
drowned in the sea. 
Of the immigrants to the Galapagos the majority 
doubtless die and leave no sign. A few will remain, 
multiply, and take possession, and their descendants are 
Island life. 
