470 TROPICAL NATURE 



earth thus attached to birds' feet several plants were raised. 

 As showing the importance of this mode of transport, an 

 experiment was made with six and three -fourths ounces of 

 mud taken from the edge of a little pond, and it was found 

 to contain the enormous number of five hundred and thirty- 

 seven seeds of several distinct species ! This was proved by 

 keeping the mud under glass and pulling up each plant as it 

 appeared, and at the end of six months the result was as 

 given above. It was also found that small portions of aquatic 

 plants were often entangled in the feet of birds, and to these 

 as well as to the feet themselves, molluscs or their eggs were 

 found to be attached, furnishing a mode of distribution for 

 such organisms. Experiments were also made on the power 

 of land-shells to resist the action of sea- water ; and we have 

 already referred to the observations on volcanic dust carried 

 far out to sea, illustrating the facilities for the wide extension 

 by aerial currents of such plants as have very minute or very 

 light seeds. l The facts are of so anomalous and apparently 

 contradictory a character that, on the old hypothesis of the 

 special independent creation of each species, no rational 

 explanation of them could be found ; and we may fairly 

 claim that the clear and often detailed explanation which can 

 be given by means of the theories and investigations of 

 Darwin, lend a powerful support to his views, and go far to 

 complete the demonstration of their correctness. 



Our space will not permit us to do more than advert to 

 the numerous ingenious explanations and suggestions with 

 which the Origin of Species abounds, such as, for example, the 

 strange fact of so many of the beetles of Madeira being wing- 

 less, while the same species, or their near allies on the con- 

 tinent of Europe, have full powers of flight ; and that this is 

 not due to any direct action of climate or physical conditions 

 is proved by the equally curious fact that such species of 

 insects as have wings in Maderia, have them rather larger 

 than usual. Equally new and important is the Darwinian 

 explanation of the form of the bees' cell, which is shown to 



i This series of observations and experiments, supplemented by those of 

 other observers, have been applied by the writer of this article to explain in 

 some detail the remarkable phenomena presented by the distribution of 

 animals and plants over the chief islands of the glooe. See Island Life. 

 Macmillan and Co. 



