How are we to represent to our minds the nature of the forces which apply to the innumerable cases of which the above is a type? Reinke, who deals exhaustively with this question, conceives the vitality of living things, manifested in growth, development, and reproduction, as lodged in what he calls “Dominants.”[88] These dominants exist in all parts of the organism, and govern those processes which ordinary physical laws do not explain, _i.e._ the phenomena which are specifically vital. They are not themselves chemical or physical energies, but they guide these energies toward the fulfilment of the objects of life.
“Dominants,” he writes,[89] “are those secondary[90] forces in the organism whose existence we recognize in their operations, but which we cannot further analyse. Thus I understand under this form that principle of control which takes effect in every organism and which sways whatever energies are available just as men use tools and machines. Since this control is manifold in its manifestations, one is obliged, when seeking for a technical designation for it, to express it in the plural. The dominants are therefore an abstraction; a symbol for phenomena, just like the conceptions, Force, Matter, the Atom, etc.; the term has been devised in order to provide a short explanatory description of certain essential processes.
“I therefore repel the objection, if anyone should make it, that the dominants are a fiction, a troop of ghosts with which I have peopled the cells and organs of animals and plants. They are, in some sense, merely a paraphrase of the description of certain phenomena, a personification of forces not to be ranged under the conception of energy—the _directive_ impulses in the animal and vegetable world.”
To continue Reinke’s explanation: Two different classes of dominants are to be recognized. These are the operative and the formative. The former control principally the chemical activities of the organism, as when a plant turns inorganic substances into sugar, albumen, etc.; the latter are the invisible architects in the organism who control its form and structure. Both are heritable, and are capable of modification within certain limits. Closely bound up with matter and energy, they are neither matter nor energy. They can be indefinitely multiplied and (to all appearance) totally destroyed. Their multiplication does not abstract energy from other known sources, nor does their destruction restore it; they do not therefore come (visibly) under the law of the conservation of energy. They operate entirely within the framework of natural laws, and can only utilize what energies are available for them at the given time and place. Every cell has its dominants; and as an organism is a synthesis, not a mere aggregate, of cells, so its individual dominant is a synthesis of the dominants of its parts. The evolution of species, like the development of an embryo, is under the control of dominants. The conditions under which they work for this end are material and physical; these conditions can, to a great extent, be ascertained and defined, but the driving force lies beyond scientific analysis.
