The edible snail, still
scattered thinly over our southern downs, and abundant at Box Hill and a
few other spots in Surrey or Sussex, was brought over, they tell us, by
the same luxurious Italian epicures, and is even now confined,
imaginative naturalists declare, to the immediate neighbourhood of Roman
stations. The mediaeval monks, in like manner, introduced the carp for
their Friday dinners. One of our commonest river mussels at the present
day did not exist in England at all a century ago, but was ferried
hither from the Volga, clinging to the bottoms of vessels from the Black
Sea, and has now spread itself through all our brooks and streams to the
very heart and centre of England. Thus, from day to day, as in society
at large, new introductions constantly take place, and old friends die
out for ever. The brown rat replaces the old English black rat; strange
weeds kill off the weeds of ancient days; fresh flies and grubs and
beetles crop up, and disturb the primitive entomological balance. The
bustard is gone from Salisbury Plain; the fenland butterflies have
disappeared with the drainage of the fens. In their place the red-legged
partridge invades Norfolk; the American black bass is making himself
quite at home, with Yankee assurance, in our sluggish rivers; and the
spoonbill is nesting of its own accord among the warmer corners of the
Sussex downs.
In the plant world, substitution often takes place far more rapidly.
Pages:
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163