Untitled - The Alfred Russel Wallace Website

382 NOTES OF A BOTANIST CHAP.
some bone to pick. They bear on many problems
for which there do not yet exist materials, nor do I
possess the skill requisite to arrive at a correct
solution. On one I point only am pretty clear, viz.
that almost every kind of animal now existing in
Cisandine Tropical America might find suitable
food and lodging on any parallel between the
southern tropic and the mouth of the Orinoco ;
which is as much as to say that they would find
everywhere either the one plant they most delighted
to feed on or others which might suit them almost
or quite as well. The continual substitution of new
forms encountered as we advance in any direction
does not, on a superficial view, show much corre-
a fact which
spondence between animals and plants
Suppose on a given
may be put otherwise, thus :
area at the foot of the Andes every species of some
class of animals to be distinct from those of the
same class on an equal area at the mouth of the
Amazon, it does not therefore follow that every
plant is different on the two areas ; we
know,
indeed, that such is not the case. Yet the modifi-
cations that have been and are still in progress
among vegetable forms must have some correspondence
with those that take place in animals ;
for all the realms of Nature act and react on each
other. The atmosphere and the earth (with its
productions, animal and vegetable) are continually
and as their actual relations to
giving and taking ;
each other vary more widely at different points
along the equatorial belt than elsewhere on the
earth's surface, it is plain that what seems equilibrium
is either oscillation or progress in some
direction. If plants were the only organic exist-