ral Philosophy—"a book which he had studied more than any other work of science—I read on the fly-leaf, written by his own hand, these words:
"In Nature's infinite book of secrecy
A little I can read."—Shakespeare.
And did he not read a little "in Nature's infinite book of secrecy"? and did he not read that little carefully and well? May we all read our little in that book as modestly and as reverently as did Joseph Henry!
WHAT does the story of life upon the earth teach us concerning the unfoldment of organic form? Is the human figure a chance result of an evolutionary force which might have pursued some quite different direction; or are the laws of development such as to lead inevitably toward the form of man as their highest organic product? This is a question admitting of a more definite answer than may at first thought appear, as we hope to show by a rapid survey of the various stress of the process.
And, first, it must be borne in mind that Nature's efforts at animal and plant formation have been on no contracted scale. The varying forms produced have been almost multitudinous. They exist at present in the greatest variety. But the present is only the apex of a long succession of life-epochs, each with its special organic group. We must multiply the existing forms by thousands of such epochs to obtain any adequate idea of the whole broad field of life. Plainly, then. Nature has not dealt sparsely with the subject, but has produced a most generous profusion of differing forms. Hence, narrow as is the field of the earth, there is reason to believe that the form-evolving principle has had full opportunity here to act. and that it has selected out the most favorable line of development from the many directions attempted.
Life is an incessant battle—a battle for food, and a battle for safety. The total quantity of food is limited. The powers of organic increase are unlimited. Thus a fight for food becomes necessary; a conflict in which no quarter is asked and none given. Victory inclines to the strongest and best armed. The successful combatant must have powers of defense against all Nature's attacks, and of assault against all Nature's defenses. In other words, the organism best adapted to its environment will win.
And this incessant weeding-out process is not confined to mature