398 TROPICAL NATURE VI 
very minute and are. carried abroad by the ee or they are 
violently expelled and scattered by the bursting of the con- 
taining capsules. Others are downy or winged, and are 
carried long distances by the gentlest breeze, or they are 
hooked and stick to the fur of animals. But there is a large 
class of seeds which cannot be dispersed in either of these 
ways, and they are mostly contained in eatable fruits. These 
fruits are devoured by birds or beasts, and the hard seeds 
pass through their stomachs undigested, and, owing probably 
to the gentle heat and moisture to which they have been sub- 
jected, in a condition highly favourable for germination. The 
dry fruits or capsules containing the first two classes of seeds 
are rarely, if ever, conspicuously coloured, whereas the eatable 
fruits almost invariably acquire a bright colour as they ripen, 
while at the same time they become soft and often full of 
agreeable juices. Our red haws and hips, our black elder- 
berries, our blue sloes and whortleberries, our white mistletoe 
and snowberry, and our orange sea-buckthorn, are examples 
of the colour-sign of edibility ; and in every part of the world 
the same phenomenon is found. Many such fruits are poison- 
ous to man and to some animals, but they are harmless to 
others; and there is probably nowhere a brightly coloured 
pulpy fruit which does not serve as food for some species of 
bird or mammal. 
Protective Colours of Fruits 
The nuts and other hard fruits of large forest-trees, though 
often greedily eaten by animals, are not rendered attractive 
to them by colour, because they are not intended to be eaten. 
This is evident, for the part eaten in these cases is the seed 
itself, the destruction of which must certainly be injurious to 
the species. Mr. Grant Allen, in his ingenious work on 
Physiological Afsthetics, well observes that the colours of all 
such fruits are protective—green when on the tree, and thus 
hardly visible among the foliage, but turning brown as they 
ripen and fall on the ground, as filberts, chestnuts, walnuts, 
beechnuts, and many others. It is also to be noted that 
many of these are specially though imperfectly protected, 
some by a prickly coat as in the chestnuts, or by a nauseous 
covering as in the walnut; and the reason why the protection 
