Plain Facts for Old and Young

As before remarked, reproduction is a function common to all animals and to all plants. Every organized being has the power to reproduce itself, or to produce, or aid in producing, other individuals like itself. It is by means of this function that plants and animals increase or multiply.

When we consider the great diversity of characters illustrated in animal and vegetable life, and the infinite variety of conditions and circumstances under which organized creatures exist, it is not surprising that modes of reproduction should also present great diversity both in general character and in detail. We shall find it both interesting and instructive to consider some of the many different modes of reproduction, or generation, observed in different classes of living beings, previous to entering upon the specific study of reproduction in man. Before doing thus, however, let us give brief attention to a theoretical form of generation, which cannot be called reproduction, known as

Spontaneous Generation.—By this term is meant the supposed formation of living creatures directly from dead matter without the intervention of other living organisms. The theory is, in substance, an old one. The ancients supposed that the frogs and other small reptiles so abundant in the vicinity of slimy pools and stagnant marshes, were generated spontaneously from the mud and slime in which they lived. This theory was, of course, abandoned when the natural history of reptiles became known.

For several thousand years the belief was still held that maggots found in decaying meat were produced spontaneously; but it was discovered, centuries ago, that maggots are not formed if the flesh is protected from flies, since they are the larvæ, or young, of a species of this insect. A relic of the ancient belief in spontaneous generation is still found in the supposition that horse-hair snakes, so-called, are really formed from the hairs of horses. This belief is quite common, but science long ago exposed its falsity.

When the microscope was discovered it revealed a whole new world of infinitesimal beings which were at first supposed to be of spontaneous origin; but careful scientific investigation has shown that even these mere specks of life are not independent of parentage. M. Pasteur and, more recently, Prof. Tyndall, with many other distinguished scientists, have demonstrated this fact beyond all reasonable chance for question.

It may be queried, If it be true that life is but a manifestation of the ordinary forces of matter,—which are common to both dead and living matter,—being dependent upon arrangement, then why may it not be that dead matter may, through the action of molecular laws, and without the intervention of any living existence, assume those peculiar forms of arrangement necessary to constitute life, as supposed by the advocates of the theory in question? It is true that some who recognize the fact that life is the result of organization maintain the doctrine of spontaneous generation; that is, the production of life without any agency other than the recognized forces of nature being brought about simply by a fortuitous combination of atoms. Although this doctrine cannot be said to be inconsistent with the theory of life presented, yet it is by no means a legitimate or necessary result of it; and observation proves its falsity.

The testimony of all nature, as almost universally admitted by scientific men, is that life originated through a creative act by the first Great Cause, who gave to certain bodies the requisite arrangement or organization to enable them to perform certain functions, and delegated to them the power to transmit the same to other matter, and thus to perpetuate life. The Creator alone has the power to originate life. Man, with all his wisdom and attainments, cannot discover the secret of organization. He may become familiar with its phenomena, but he cannot unravel, further, the mystery of life. The power of organizing is possessed only by the lower class of living or organized bodies, those known as vegetable organisms or plants. A grain of wheat, a kernel of corn, a potato, when placed under favorable conditions, takes the inert, lifeless particles of matter which lie about it in the earth and air, and organizes them into living substances like itself.

To man and animals the Creator delegated the power to form their own peculiar structures from the vitalized tissues of plants. Thus, both animal and vegetable life is preserved without the necessity of continued acts of creative power, each plant and each animal possessing the power not only to preserve its own life, but also to aid, at least, in the perpetuation of the species. The record of creation in Genesis harmonizes perfectly with this view, it being represented that God formed (organized or arranged) man, animals, and vegetable productions from the earth.

Simplest Form of Generation.—Deep down beneath the waters of the ocean, covering its bottom in certain localities, is found a curious slime, which, under the microscope, is seen to be composed of minute rounded masses of gelatinous matter, or protoplasm. By watching these little bodies intently for a few minutes, the observer will discover that each is a living creature capable of moving, growing, and assuming a variety of shapes. Continued observation will reveal the fact that these little creatures multiply; and a more careful scrutiny will enable him to see how they increase. Each divides into two equal parts so nearly alike that they cannot be distinguished apart. In this case the process of generation is simply the production of two similar individuals from one.

A small quantity of slime taken from the surface of a stone near the bottom of an old well, or on the seaside, when placed under the microscope, will sometimes be found to contain large numbers of small, round, living bodies. Careful watching will show that they also multiply by division; but before the division occurs, two cells unite to form one by a process called conjugation. Then, by the division of this cell, instead of only two cells, a large number of small cells are formed, each of which may be considered as a bud formed upon the body of the parent cell and then separated from it to become by growth an individual like its parent, and, like it, to produce its kind. In this case, we have new individuals formed by the union of two individuals which are to all appearance entirely similar in every particular.

Sex.—Rising higher in the scale of being, we find that, with rare exceptions, reproduction is the result of the union of two dissimilar elements. These elements do not, in higher organisms, as in lower forms of life, constitute the individuals, but are produced by them; and being unlike, they are produced by special organs, each adapted to the formation of one kind of elements. The two classes of organs usually exist in separate individuals, thus giving rise to distinctions of sex; an individual possessing organs which form one kind of elements being called a male, and one possessing organs for the formation of the other kind of elements, a female. The sexual differences between individuals of the same species are not, however, confined to the sexual organs. In most classes of plants and animals, other sexual differences are very great. In some of the lower orders of animals, and in many species of plants, the male and female individuals are so much unlike that for a long time after they were well known, no sexual relation was discovered.

Hermaphrodism.—An individual possessing both male and female organs of reproduction is called an hermaphrodite. Such a combination is very rare among higher animals; but it is by no means uncommon among plants and the lower forms of animal life. The snail, the oyster, the earth-worm, and the common tape-worm, are examples of true hermaphrodites. So-called human hermaphrodites are usually individuals in whom the sexual organs are abnormally developed so that they resemble those of the opposite sex, though they really have but one sex, which can usually be determined with certainty. Only a very few cases have been observed in which both male and female organs were present.