Let us look at man and ask the question: What is there about him which would need an independent act of creation any more than about the "mountain of granite or the atom of sand"? The answer comes back: Besides life, man has many mental attributes. Let us direct our attention at first to the grand phenomena of life, and then to man's attributes.
To discover the nature of life, to find out what life really is, it would be folly to commence by comparing man, the perfection of living beings, with an inorganic or inanimate substance like a brick, to discover the hidden secret; for, as Professor Orton says:[3] "That only is essential to life which is common to all forms of life. Our brains, stomach, livers, hands and feet are luxuries. They are necessary to make us human, but not living beings." Instead of man, then, it will be necessary for us to take the simplest being which possesses such a phenomena; and such are the little homogeneous specks of protoplasm, constituting the Group Monera, which are entirely destitute of structure, and to which the name "Cytode" has been given. In the fresh waters in the neighborhood of Jena minute lumps of protoplasm were discovered by Haeckel, which, on being examined under the most powerful lens of a microscope, were seen to have no constant form, their outlines being in a state of perpetual change, caused by the protrusion from various parts of their surface of broad lobes and thick finger-like projections, which, after remaining visible for a time, would be withdrawn, to make their appearance again on some other part of the surface. To this little mass of protoplasm Haeckel has given the name Protanæba primitiva. These little lumps multiply by spontaneous division into two pieces, which, on becoming dependent, increase in size and acquire all the characteristics of the parent. From this illustration, it will be seen that "reproduction is a form of nutrition and a growth of the individual to a size beyond that belonging to it as an individual, so that a part is thus elevated into a (new) whole."
It is to this simple state of the monera the fertilized egg of any animal is transformed—the germ vesicle; the original egg kernel disappears, and the parent kernel (cytococcus) forms itself anew; and it is in this condition, a non-nucleated ball of protoplasm, a true cytod, a homogeneous, structureless body, without different constituent parts, that the human child, as well as all other living beings, take their first steps in development. No matter how wonderful this may seem, the fact stares us in the face that the entire human child, as well as every animal with all their great future possibilities, are in their first stage a small ball of this complex homogeneous substance. Whether we consider "a mere infinitesimal ovoid particle which finds space and duration enough to multiply into countless millions in the body of a living fly, and then of the wealth of foliage, the luxuriance of flower and fruit which lies between this bald sketch of a plant and the gigantic pine of California, towering to the dimensions of a cathedral spire, or the Indian fig which covers acres with its profound shadow, and endures while nations and empires come and go around its vast circumference," or we look "at the other half of the world of life, picturing to ourselves the great finner whale, hugest of beasts that live or have lived, disporting his eighty or ninety feet of bone, muscle, and blubber, with easy roll, among the waves in which the stoutest ship that ever left dock-yard would founder hopelessly, and contrast him with the invisible animalcule, mere gelatinous specks, multitudes of which could in fact dance upon the point of a needle with the same ease as the angels of the schoolman could in imagination;—with these images before our minds, it would be strange if we did not ask what community of form or structure is there between the fungus and the fig-tree, the animalcule and the whale? and, à fortiori, between all four? Notwithstanding these apparent difficulties, a threefold unity—namely, a unity of power or faculty, a unity of form, and a unity of substantial composition—does pervade the whole living world."[4] And this unit is Protoplasm. So we see it is necessary for us to retreat to our protoplasm as a naked formless plasma, if we would find freed from all non-essential complications the agent to which has been assigned the duty of building up structure and of transforming the energy of lifeless matter into the living. Even Goethe (in 1807) almost stated this when he said: "Plants and animals, regarded in their most imperfect condition, are hardly distinguishable. This much, however, we may say, that from a condition in which plant is hardly to be distinguished from animal, creatures have appeared, gradually perfecting themselves in two opposite directions—the plant is finally glorified into the tree, enduring and motionless; the animal into the human being of the highest mobility and freedom."
Let us examine for a moment this substance Protoplasm, and see in what way it differs from inorganic matter, or in what way the animate differs from the inanimate—the living from the dead.
Felix Dujardin, a French zoologist (1835) pointed out that the only living substance in the body of rhizopods and other inferior primitive animals, is identical with protoplasm. He called it sarcode. Hugo von Mohl (1846) first applied the name protoplasm to the peculiar serus and mobile substance in the interior of vegetable cells; and he perceived its high importance, but was very far from understanding its significance in relation to all organisms. Not, however, until Ferdinand Cohn (1850) and more fully Franz Unger (1855) had established the identity of the animate and contractile protoplasm in vegetable cells and the sarcode of the lower animals, could Max Shultz in 1856-61 elaborate the protoplasm theory of the sarcode so as to proclaim protoplasm to be the most essential and important constituent of all organic cells, and to show that the bag or husk of the cell, the cellular membrane and intercellular substance, are but secondary parts of the cell, and are frequently wanting. In a similar manner Lionel Beale (1862) gave to protoplasm, including the cellular germ, the name of "germinal matter," and to all the other substance entering into the composition of tissue, being secondary, and produced the name of "formed matter."
"Wherever there is life there is protoplasm; wherever there is protoplasm, there, too, is life." The physical consistence of protoplasm varies with the amount of water with which it is combined, from the solid form in which we find it in the dormant state to the thin watery state in which it occurs in the leaves of valisneria.
As to its composition, chemistry can as yet give but scanty information; it can tell that it is composed of carbon, hydrogen, oxygen, nitrogen, sulphur, and phosphorus, and it can also tell the percentage of each element, but it cannot give more than a formula that will express it as a whole, giving no information as to the nature of the numerous albuminoid substances which compose it. Edward Cope, in his article on Comparative Anatomy,[5] gives the formula for protoplasm (as a whole), C24H17N3O8 + S and P, in small quantities under some circumstances. It is therefore, he says, a nitryl of cellulose: C24H20O2 + 3NH3. According to Mulder the composition of albumen, one of the class of protein substances to which protoplasm belongs, is 10(C40H31N5O12) + S2P. Protoplasm is identical in both the animal and vegetable kingdom; it behaves the same from whatever source it may be derived towards several re-agents, as also electricity. Is it possible, then, that the protoplasm which produces the mould is exactly the same composition as that which produces the human child? The answer is Yes, so far as the elements are concerned, but the proportions of carbon, hydrogen, etc., must enter into an infinite number of diverse stratifications and combination in the production of the various forms of life. Professor Frankland, speaking of protein, for instance, says it is capable of existing under probably at least a thousand isomeric forms. Protoplasm may be distinguished under the microscope from other members of the class to which it belongs, on account of the faculty it possesses of combining with certain coloring matters, as carmine and aniline; it is colored dark-red or yellowish-brown by iodine and nitric acid, and it is coagulated by alcohol and mineral acids as well as by heat. It possesses the quality of absorbing water in various quantities, which renders it sometimes extremely soft and nearly liquid, and sometimes hard and firm like leather. Its prominent physical properties are excitability and contractility, which Kühne and others have especially investigated. The motion of protoplasm in plants was first made known by Bonaventure Corti a century ago in the Charœ plants; but this important fact was forgotten, and it had to be discovered by Treviranus in 1807. The regular motion of the protoplasm, forming a perfect current, may be seen in the hairs of the nettle, and weighty evidence exists that similar currents occur in all young vegetable cells. "If such be the case," says Huxley, "the wonderful noonday silence of a tropical forest is, after all, due only to the dullness of our hearing, and could our ears catch the murmur of these tiny maelstroms, as they whirl in innumerable myriads of living cells, which constitute each tree, we should be stunned as with a roar of a great city."
One step higher in the scale of life than the monera is the vegetable or animal cell, which arose out of the monera by the important process of segregation in their homogeneous viscid bodies, the differentiation of an inner kernel from the surrounding plasma. By this means the great progress from a simple cytod (without kernel) into a real cell (with kernel) was accomplished. Some of these cells at an early stage encased themselves by secreting a hardened membrane; they formed the first vegetable cells, while others remaining naked developed into the first aggregate of animal cells. The vegetable cell has usually two concentric coverings—cell-wall and primordial utricle. In animal cells the former is wanting, the membrane representing the utricle. As a general fact, also, animal cells are smaller than vegetable cells. Their size[6] varies greatly, but are generally invisible to the naked eye, ranging from 1⁄500 to 1⁄10000 of an inch in diameter. About four thousand of the smallest would be required to cover the dot put over the letter i in writing. The shape of cells varies greatly; the normal form, though, is spheroidal as in the cells of fat, but they often become[7] many-sided—sometimes flattened as in the cuticle, and sometimes elongated into a simple filament as in fibrous tissue or muscular fibre.
The cell, therefore, is extremely interesting, since all animal and vegetable structure is but the multiplication of the cell as a unit, and the whole life of the plant or animal is that of the cells which compose them, and in them or by them all its vital processes are carried on. It may sound paradoxical to speak of an animal or plant being composed of millions of cells; but beyond the momentary shock of the paradox no harm is done.
The cell, then, can be regarded as the basis of our physiological idea of the elementary organism; but in the animal as well as in the plant, neither cell-wall nor nucleus is an essential constituent of the cell, inasmuch as bodies which are unquestionably the equivalents of cells—true morphological units—may be mere masses of protoplasm, devoid alike of cell-wall or nucleus. For the whole living world, then, the primary and a mental form of life is merely an individual mass of protoplasm in which no further structure is discernible. Well, then, has protoplasm been called the "universal concomitant of every phenomena of life." Life is inseparable from this substance, but is dormant unless excited by some external stimulant, such as heat, light, electricity, food, water, and oxygen.