A recently published account of the New Flora of the volcanic island of Krakatau furnishes an instructive and remarkable demonstration of the facility with which a completely sterilised island, separated by several miles of ocean from neighbouring lands, may be restocked with vegetation(24). In 1883 the island of Krakatau, then densely covered with a luxuriant tropical vegetation, was partially destroyed by a series of exceptionally violent volcanic explosions. After this catastrophe only a third of the island was left: the surface was deeply covered by pumice and volcanic ash and no vestige of life remained. In 1906 a party of botanists who spent a few hours on Krakatau collected 137 species of plants: the vegetation was in places so dense that it was with the greatest difficulty they penetrated beyond the coastal belt, and some of the trees had reached a height of 50 feet. The seeds and fruits of this new flora have been carried by ocean-currents, by wind, and by the agency of birds from other islands in the Malay Archipelago. The nearest islands, except the small island of Sebesi, about 12 miles distant, are Java and Sumatra, separated from Krakatau by a stretch of water about 25 miles in breadth. It is reasonable to wonder whether, had Forbes known of this and similar modern instances of the capabilities of plants as travellers, he would have adopted the view he did. In this connexion it may be added that in recent years the glaciation of Ireland has been shown to be more extensive than it was believed to be when Forbes wrote his essay. There would seem to be no insuperable objection to the conclusion that the Mediterranean plants in Ireland and in the south of England reached their present home after the retreat of the ice at the end of the Glacial period, and after Ireland became an island. A full consideration of the problem is beyond the scope of this book, but I have briefly stated the case, not with the authority of an expert but in order to draw attention to a particularly fascinating study in plant-migration. [Illustration: Fig. 2. _Eriocaulon septangulare_ With. West Connemara. (Photograph by Mr W. R. Welch.) ]