University of Virginia Library

1. Sex in Living Forms.

LIFE, in its great diversity of forms, has ever been a subject of the deepest interest to rational beings. Poets have sung of its joys and sorrows, its brilliant phantasies and harsh realities. Philosophers have spent their lives in vain attempts to solve its mysteries; and some have believed that life was nothing more than a stupendous farce, a delusion of the senses. Moralists have sought to impress men with the truth that "life is real," and teeming with grave responsibilities. Physiologists have busied themselves in observing the phenomena of life, and learning therefrom its laws. The subject is certainly an interesting one, and none could be more worthy of the most careful attention.

Living Beings. — Man possesses life in common with other beings almost infinite in number and variety. The hugest beast that roams the forest or plows the main is no more a living creature than the smallest insect or microscopic animalculum. The "big tree" of California, and the tiny blade of grass which waves at its foot, are alike imbued with life. All nature teems with life. The practiced eye detects multitudes of living forms at every glance.

Microscopic Life. — The universe of life presents the most marvelous manifestations of the infinite power and wisdom of the Creator to be found in all his works. The

student of biology sees life in myriad forms which are unnoticed by the casual observer. The microscope reveals worlds of life that were unknown before the discovery of this wonderful aid to human vision, — whole tribes of living organisms, each of which, though insignificant in size, possesses organs as perfect and as useful to it, in its sphere, as do animals of greater magnitude.

Under a powerful magnifying glass, a drop of water from a stagnant pool is found to be peopled with curious animated forms; slime from a damp rock, or a speck of green scum from the surface of a pond, presents a museum of living wonders. Through this instrument the student of nature learns that life in its lowest form is represented by a mere atom of living matter, an insignificant speck of trembling jelly, transparent and structureless, having no organs of locomotion, yet able to move in any direction; no nerves or organs of sense, yet possessing a high degree of sensibility; no mouth, teeth, nor organs of digestion, yet capable of taking food, growing, developing, producing other individuals like itself, becoming aged, infirm, and dying, — such is the life history of a living creature at the lower extreme of the scale of animated being.

As we rise higher in the scale, we find similar little atoms of life associated together in a single individual, each doing its proper share of the work necessary to maintain the life of the individual as a whole, yet retaining, at the same time, its own individual life.

As we ascend to still higher forms, we find this association of minute living creatures resulting in the production of forms of increasing complicity. As the structure of the individual becomes more complex, and

its functions more varied, the greater is the number of separate, yet associated, organisms required to do the work.

In man, at the very summit of the scale of animate existence, we find the most delicate and wonderfully intricate living mechanism of all. In him, as in lower, intermediate forms of life, the life of the individual is but a summary of the lives of all the numberless minute organisms of which his body is composed. The individual life is but the aggregate life of all the millions of distinct individuals which are associated together in the human organism.

Animals and Vegetables. — The first classification of living creatures separates them into two great kingdoms, animal and vegetable. Although it is very easy to define the general characteristics of each of these classes it is impossible to fix upon any single peculiarity which will be applicable to every case. Most vegetable organisms remain stationary; while some possess organs of locomotion, and swim about in the water in a manner much resembling the movements of certain animals. Most vegetables obtain their nutriment from the earth and the air, while animals subsist on living matter. A few plants seem to take organic matter for food, some even catching and killing small insects.

It is found impossible to draw the precise line between animals and vegetables, for the reason just mentioned. The two kingdoms blend so intimately that in some cases it is impossible to tell whether a certain microscopic speck of life is an animal or a vegetable. But since these doubtful creatures are usually so minute that several millions of them can exist in a single drop

of water, it is seldom of practical importance whether they are animal or vegetable, or sometimes one and sometimes the other, as they have been supposed to be by some biologists.

Protoplasm. — All living creatures are organized beings. Most possess a structure and an organism more or less complicated; but some of the lowest forms are merely little masses of transparent, homogeneous jelly, known as protoplasm. Some of the smallest of these are so minute that one hundred millions of them could occupy the space of a cube one-thousandth of an inch on each side; yet each one runs its course of life as regularly as man himself, performing its proper functions even more perfectly, perhaps.

Life Force. — To every thinking mind the question often recurs, what makes the fragrant flower so different from the dead soil from which it grows? the trilling bird so vastly superior to the inert atmosphere in which it flies? What subtle power paints the rose, and tunes the merry songster's voice? To explain this mystery, philosophers of olden time supposed the existence of a certain peculiar force, which is called life, or vital force, or vitality.

This supposition does nothing more than furnish a name for a thing unknown, and the very existence of which may fairly be doubted. In fact, any attempt to find a place for such a force, to understand its origin, or harmonize its existence with that of other well-known forces, is unsuccessful; and the theory of a peculiar vital force, a presiding entity, present in every living thing, vanishes into thin air to give place to the more rational view of the most advanced modern scientists,

that vital force, so-called, is only a manifestation of the ordinary forces of nature acting through a peculiar arrangement of matter.

Life and Organization. — Life depends, not upon a peculiar force, but upon a peculiar arrangement of matter, or organization. It is simply a peculiar manifestation of the force possessed by atoms exhibited through a peculiar arrangement of atoms and molecules. This arrangement is what is known as organization; and bodies which possess it are known as organized or living bodies.

The term life may be understood as referring to the phenomena which result from organization.

That life results from organization, not organization from life, is more consonant with the accepted and established facts of science than the contrary view. We might adduce numerous facts and arguments in support of this view of the nature of life, but will not dwell longer upon the subject here, as we have considered it at some length elsewhere.

Life Force a Mystery. — That heat and mechanical force are produced by the action of the so-called vital force, is seen by observation. Through experimentation by the aid of delicate instruments, it may be shown that vital force is also convertible into electricity. In certain classes of animals, as the electric eel and certain fishes, the amount of electricity generated is so great that large animals may be paralyzed by the shock received when they come in contact with animals possessing this property. Certain other classes of the animal kingdom, as the fire-fly, etc., possess the still more remarkable property of converting vital heat into

light. The doctrine of the correlation of forces would certainly lead to the supposition that the forces mentioned are likewise converted into vital action, and the phenomena of animal nutrition also point strongly in this direction.

How the common forces of nature are converted into life force, or vital force, is a question we shall not undertake to answer, except to say that it is through organization. How vital force is converted into heat, light, electricity, and magnetism, is a problem equally difficult of solution. How gravitation acts upon matter; how one particle of matter acts upon another; how light travels; how force is transmitted from one object to another, as from a driving belt to the pulley which is propelled by it, — these are all questions which, though apparently easy and simple, are quite beyond the ability of the most profound scientist to answer.