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 ? And if 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 



Island life. ^11 i, ^ j • j i- ^ 



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 



