It is a history treating of successive
eras. There is first the period of the dominance of reproduction and
digestion, purely vegetative functions, characteristics of the plant
just as truly as of the animal. This period extends from the
beginning of life up to the time when the annelid was the highest
living form yet developed. But in insects and lower vertebrates
another system has risen to dominance. This is muscle. The
vertebrate no longer devotes all, or the larger part, of its income
to digestion and reproduction. If it did, it would degenerate or
disappear. The stomach and intestine are improved, but only that
they may furnish more abundant nutriment for building and supporting
more powerful muscles better arranged. The history of vertebrates is
a record of the struggle for supremacy between successive groups of
continually greater and better applied muscular power. Here strength
and activity seem to be the goal of animal development, and the
prize falls to the strongest or most agile. The earth is peopled by
huge reptiles, or mammals of enormous strength, and by birds of
exceeding swiftness. This portion of our history covers the era of
muscular activity.
But these huge brutes are mostly doomed to extinction, and the bird
fails of supremacy in the animal kingdom. "The race is not to the
swift, nor the battle to the strong.
Pages:
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159