ScHARFF — Former Ldiiil-Bridfie between N. Europe mid N. America. 9 



protruded here and tliere, exposing the blasted and carbonized remains of 

 tree-stems."' 



Within sixty days after the eruption the ashes had been washed away 

 to such an extent as to expose the original surface in certain parts. I wonder 

 how many stems of the tropical forest alluded to were crowded with insect 

 life, and to wliat temperature tlie interior of these tree-trunks ro.se when the 

 external parts were charred, or to what deptli of soil the heat of the hot 

 ashes penetrated ? I should have imagined that multitudes of insects or 

 their larvae, and countless seeds, would have survived the ordeal thai 

 Dr. Ernst so vividly describes. At any rate, I can fancy a naturalist, 

 imbued with Darwin's methods of research, eager to root up these dead 

 tree-stumps in order to examine what seeds and what insects were still 

 living in the soil beneath or in the adjoining rock-crevices. Nothing of the 

 kind was attempted ! We are simply informed that all organic life had been 

 destroyed. It is well known that such seeds as can stand desiccation are 

 extremely resistant to heat when dry, and may not be injured by the tempera- 

 ture of boiling water. Would the lieat of the hot ashes penetrating into 

 the soil destroy all vitality among the seeds contained therein ? I think 

 not. And yet we are led to believe that three years after the volcanic outburst 

 in 1886 the pioneers of the new vegetation which reached the island by 

 accidental dispersal from elsewhere were seen stretching from the shore to the 

 peak of the mountain. Seven years later the whole island was covered with 

 a dense, almost impenetrable thicket, and numerous insects and even lizards 

 were noticed. If dispersal really proceeded on those lines^ the study of 

 geographical distribution may be abandoned — at any rate so far as the main 

 principle of Wallace is concerned, that the study of zoogeography enables us 

 to map out the islands and continents of former epochs. That Wallace's 

 maxim has been adopted by Messrs. P. and F. Sarasin during their explora- 

 tion of Celebes, and carefully applied in their treatise on the geological history 

 of that island, implies that they do not attach much importance to accidental 

 distribution, though their labours were conducted not far from and in about 

 the same latitude as the volcanic island of Krakatau.^ 



It would be idle to deny that the seeds of certain plants are carried to 

 great distances by wind ; that many others are undoubtedly transported by 

 ocean currents; that some seeds are even scattered here and theie by birds. 

 My contention is — and I concur in this opinion with many eminent botanists — 

 that onlya small percentage of plants are disseminated and actually established 



' Ernst, " L\ew Flora of Kriikatau," p. 4. 



■ Sarasin, P. and F., " Geol. Gescbichtc d. Insel Celebes." 



R.I. A, PROC, VOL. XXVin., SECT. B. [C] 



