Means of Dispersal. 31 
Accidents of this sort, however, are not absolutely 
necessary for the. dispersal of the seeds ; for a considerable 
number, even of such soft seeds as that of the Ivy, are 
passed with their vitality unimpaired. This is often the 
case when the bird or other animal has been feeding 
greedily ; and at such times the bird may throw up great 
part of its food undigested, especially if it is startled.® 
Birds, especially young birds, as Professor Lloyd 
Morgan has shown, learn by experience, and try various 
unsuitable foods. This must often lead to their eating 
indigestible, poisonous, or aperient fruits, which are not 
commonly taken. So many fruits have medicinal qualities 
that these in many cases may be special adaptations to aid 
the dispersal of the seeds. The migrating bird in its first 
year is constantly coming across plants new to it, and this 
at times when it is too tired and hungry to discriminate. 
Mammals also must have greatly aided the dispersal of 
seeds in former times, for an ox, a deer, or a horse falling 
over the cliffs of France would tend to drift with the 
prevalent south-west wind till it was thrown upon the 
English Coast, where wolves and foxes would pull it to 
pieces, dragging the remains beyond the reach of the sea, 
and perhaps burying parts, with the undigested vegetable 
food still contained in the stomach. 
It is needless to multiply instances, enough has been 
said to show that the special modes of transportation 
studied by Lyell and Darwin, added to the accumulated 
accidents of some thousands of years, are sufficient to 
account for the introduction of the whole of our native 
plants, without the necessity for any continuous land con- 
nexion between the different islands, or with the Continent. 
Indeed the constant rain of seeds over our Islands 
is probably on such a scale that were it not for the 
* E. M, Langley, ature, December 15th, 1898. 
