and colloid substances—Life of crystals—Growth of crystals—Waves of growth—Metabolism—Catalysis—Fermentation—Biogenesis—Vital force—Old and new vitalism—Palavitalism—Antivitalism—Neovitalism.
As the object of this work is the critical study of the wonders of life, and a knowledge of the truth concerning them, we must first of all form a clear idea of the meaning of "life" and "wonder," or miracle. For thousands of years men have appreciated the difference between life and death, between living and lifeless bodies; the former are called organisms, and the latter known as inorganic bodies. Biology—in the widest sense—is the name of the science which treats of organisms; we might call the science which deals with the inorganic "abiology," abiotik, or anorgik. The chief difference between the two provinces is that organisms accomplish peculiar, periodically repeated, and apparently spontaneous movements, which we do not find in inorganic matter. Hence life may be conceived as a special process of movement. Recent study has shown that this is always connected with a particular chemical substance, plasm, and consists essentially in a circulation of matter, or metabolism. At the same time modern science has shown that the sharp distinction formerly drawn between the organic and the inorganic cannot be sustained, but that the two kingdoms are profoundly and inseparably united.
Of all the phenomena of inorganic nature with which the life-process may be compared, none is so much like it externally and internally as the flame. This important comparison was made two thousand four hundred years ago by one of the greatest philosophers of the Ionic school, Heraclitus of Ephesus—the same thinker who first broached the idea of evolution in the two words, Panta rei—all things are in a state of flux. Heraclitus shrewdly conceived life as a fire, a real process of combustion, and so compared the organism to a torch.
Max Verworn has lately employed this metaphor with great effect in his admirable work on general physiology, and has especially dealt with the comparison of the individual life-form with the familiar butterfly shape of the gas-flame. He says:
The comparison of life to a flame is particularly suitable for helping us to realize the relation between form and metabolism. The butterfly-shape of a gas-flame has a very characteristic outline. At the base, immediately above the burner, there is still complete darkness; over this is a blue and faintly luminous zone; and over this again the bright flame expands on either side like the wings of a butterfly. This peculiar form of the flame, with its characteristic features, which are permanent, as long as we do not interfere with the gas or the environment, is solely due to the fact that the grouping of the molecules of the gas and the oxygen at various parts of the flame is constant, though the molecules themselves change every moment. At the base of the flame the molecules of the gas are so thickly pressed that the oxygen necessary for their combustion cannot penetrate; hence the darkness we find here. In the bluish zone a few molecules of oxygen have combined with the molecules of the gas: we have a faint light as the result. But in the body of the flame the molecules of the gas are so freely combined with the oxygen of the atmosphere that we have a lively combustion. However, the exchange of matter (metabolism) between the outpouring gas and the surrounding air is so regulated that we always find the same molecules in the same quantity at the same spot. Thus we get the permanent flame, with all its characteristics. But if we alter the circulation by lessening the stream of gas, the shape of the flame changes, because now the disposition of the molecules on both sides is different. Thus the study of the gas-jet gives us, even in detail, the features we find in the structure of the cell.
The scientific soundness of this metaphor is all the more notable as the phrase, "the flame of life," has long been familiar both in poetry and popular parlance.
In the sense in which science usually employs the word "organism," and in which we employ it here, it is equivalent to "living thing" or "living body." The opposite to it, in the broad sense, is the anorganic or inorganic body. Hence the word "organism" belongs to physiology, and connotes essentially the visible life-activity of the body, its metabolism, nutrition, and reproduction.
However, in most organisms we find, when we examine their structure closely, that this consists of various parts, and that these parts are put together for the evident purpose of accomplishing the vital functions. We call them organs, and the manner in which they are combined, apparently on a definite plan, is their organization. In this respect, we compare the organism to a machine in which some one has similarly combined a number of (lifeless) parts for a definite purpose, but according to a preconceived and rationally initiated design.
The familiar comparison of an organism to a machine has given rise to very serious errors in regard to the former, and has, of late, been made the base of false dualistic principles. The modern "machine-theory of life" which is raised thereon demands an intelligent design and a deliberate constructing engineer for the origin of the organism, just as we find in the case of the machine. The organism is then very freely compared to a watch or a locomotive. In order to secure the regular working of such a complicated mechanism, it is necessary to arrange for a perfect co-operation of all its parts, and the slightest accident to a single wheel suffices to throw it out of gear. This figure was particularly employed by Louis Agassiz (1858), who saw "an incarnate thought of the Creator" in every species of animal and plant. Of late years it has been much used by Reinke in the support of his theosophic dualism. He described God, or "the world-soul," as the "cosmic intelligence," but ascribes to this mystic immaterial being the same attributes that the catechism and the preacher give to the Creator of heaven and earth. He compares the human intelligence which the watch-maker has put into the elaborate structure of the watch with the "cosmic intelligence" which the Creator has put in the organism, and insists that it is impossible to deduce its purposive organization from its material constituents. In this he entirely overlooks the immense difference between the "raw material" in the two cases. The "organs" of the watch are metallic parts, which fulfil their purpose in virtue only of their physical properties (hardness, elasticity, etc.). The organs of the living organism, on the other hand, perform their functions chiefly in virtue of their chemical composition. Their soft plasma-body is a chemical laboratory, the highly elaborate molecular structure of which is the historical product of countless complicated processes of heredity and adaptation. This invisible and hypothetical molecular structure must not (as is often done) be confused with the real and microscopically discoverable structure of the plasm, which is of great importance in the question of organization. If one is disposed to assume for this molecular structure a simple chemical substance, a deliberate design, and an "intelligent natural force" for cause, one is bound to do the same for powder, and say that the molecules of charcoal, sulphur, and saltpetre have been purposively combined to produce an explosion. It is well known that powder was not made according to a theory, but accidentally discovered in the course of experiment. The whole of this favorite machine-theory of life, and the far-reaching dualistic conclusions drawn from it, tumble to pieces when we study the simplest organisms known to us, the monera; for these are really organisms without organs—and without organization!
I endeavored in my Generelle Morphologie(1866) to draw the attention of biologists to these simplest and lowest organisms which have no visible organization or composition from different organs. I therefore proposed to give them the general title of monera. The more I have studied these structureless beings—cells without nuclei!—since that time, the more I have felt their importance in solving the greatest questions of biology—the problem of the origin of life, the nature of life, and so on. Unfortunately, these primitive little beings are ignored or neglected by most biologists to-day. O. Hertwig devotes one page of his three-hundred-page book on cells and tissues to them; he doubts the existence of cells without nuclei. Reinke, who has himself shown the existence of unnucleated cells among the bacteria (beggiatoa), does not say a word about their general significance. Bütschli, who shares my monistic conception of life, and has given it considerable support by his own thorough study of plasma-structures and the artificial production of them in oil and soap-suds, believes, like many other writers, that the "composition of even the simplest elementary organism from cell-nucleus and protoplasm" (the primitive organs of the cell) is indispensable. These and other writers suppose that the nucleus has been overlooked in the protoplasm of the monera I have described. This may be true for one section of them; but they say nothing about the other section, in which the nucleus is certainly lacking. To this class belong