164 STUDIES IN LIFE AND SENSE. 



chaffinch and the canary of the Madeira and the Canary Islands, 

 and the peculiar Azorean bullfinch. There are no difficulties in 

 the way of accounting satisfactorily for the existence even of these 

 latter species. The bird-population of the Azores, as a whole 

 originated in the storm-driven or chance stragglers from other lands. 

 The oriole, snow-bunting, and hoopoe even now are occasionally 

 found in the Azores ; and as the birds are most numerous in the 

 eastern islands of the Azores, Europe and Africa may be assumed to 

 be the chief sources of supply of the bird- emigrants. The bullfinch 

 of the Azores is, however, peculiar as well as interesting in its 

 history. This bullfinch is a marked variety of the European species, 

 just as other Azorean birds exhibit slight divergences from our own 

 species. We see in this bird, in fact, the beginning of that work of 

 modification, induced by the influence of new locality on the species, 

 to which is due the endless variety of the earth's population as a 

 whole. The insects and land-shells of these islands present clear 

 traces of European relationship ; and the botany of the Azores, 

 showing us 480 various species of flowering plants and ferns, also 

 declares that 440 of these species occur in Europe. Even of the 

 forty peculiar species of plants, all, save six, find a near relationship 

 in European plants ; and these six are related to the plants of the 

 Canaries and Madeira. Like the birds, the land-shells, insects, and 

 plants have reached the Azores as emigrants from the adjacent 

 continents and islands. Means of dispersal and conveyance are 

 abundant ; and Darwin has shown how common are the methods 

 whereby the lower and occasionally the higher forms of animals 

 and plants can be distributed often to vast distances from their 

 original home. Let us for a moment consider some of these casual 

 or accidental means of dispersal. 



Many seeds will, for example, resist for lengthened periods 

 the action of sea- water. Out of 87 kinds of seeds, 64 germinated 

 in Mr. Darwin's hands after twenty-eight days' immersion ; and a 

 few survived after 137 days' immersion. Ripe hazel-nuts, when 

 dried, floated for ninety days, and then germinated ; and " an 

 asparagus- plant with ripe berries floated for twenty-three days ; 

 when dried, it floated for eighty-five days, and the seeds afterwards 

 germinated." There is thus ample time and opportunity, so far as 

 the vitality of many seeds is concerned, to enable them to be trans- 

 ported safely by ocean-currents to far-distant shores. Seeds are, 

 again, often carried impacted in the earth of floating roots of 

 trees; and, as Darwin remarks, even the seeds of plants taken from 

 the crops of dead birds floating on the surface of the sea, germinate 

 when planted. Peas and vetches, " taken out of the crop of a 

 pigeon, which had floated on artificial sea-water for thirty davs, to 

 my surprise," says Darwin, " nearly all germinated." Living birds, 



