ORGANISMS.
8. It will be needful to fix with precision the terms, Organism, Life, Property, and Function.
An organism, although usually signifying a more or less complex unity of organs, because the structures which first attracted scientific attention were all thus markedly distinguished from inorganic bodies, has by the gradual extensions of research been necessarily generalized, till it now stands for any organized substance capable of independent vitality: in other words, any substance having the specific combination of elements which manifests the serial phenomena of growth, development, and decay. There are organisms that have no differentiated organs. Thus a microscopic formless lump of semifluid jelly-like substance (Protoplasm) is called an organism, because it feeds itself, and reproduces itself. There are advantages and disadvantages in such extensions of terms. These are notable in the parallel extension of the term Life, which originally expressing only the complex activities of complex organisms, has come to express the simplest activities of protoplasm. Thus a Monad is an organism; a Cell is an organism; a Plant is an organism; a Man is an organism. And each of these organisms is said to have its Life, because
“Through all the mighty commonwealth of things
Up from the creeping worm to sovereign man”[1]
there is one fundamental group of conditions, one organized substance, one vitality.
Obviously this unity is an abstraction. In reality, the life manifested in the Man is not the life manifested in the Monad: he has Functions and Faculties which the Monad has no trace of; and if the two organisms have certain vital characteristics in common, this unity is only recognized in an ideal construction which lets drop all concrete differences. The Life is different when the organism is different. Hence any definition of Life would be manifestly insufficient which while it expressed the activities of the Monad left unexpressed the conspicuous and important activities of higher organisms. A sundial and a repeater will each record the successive positions of the sun in the heavens; but although both are instruments for marking time, the sundial will not do the work of the repeater; the complexity and delicacy of the watch mechanism are necessary for its more varied and delicate uses. A semifluid bit of protoplasm will feed itself; but it will not feed and sustain a complex animal; nor will it feel and think.
9. Neglect of this point has caused frequent confusion in the attempts to give satisfactory definitions. Biologists ought to have been warned by the fact that some of the most widely accepted definitions exclude the most conspicuous phenomena of Life, and are only applicable to the vegetable world, or to the vegetal processes in the animal world. A definition, however abstract, should not exclude essential characters. The general consent of mankind has made Life synonymous with Mode of Existence. By the life of an animal is meant the existence of that animal; when dead the animal no longer exists; the substances of which the organism was composed exist, but under another mode; their connexus is altered, and the organism vanishes in the alteration. It is a serious mistake to call the corpse an organism; for that special combination which constituted the organism is not present in the corpse. This misconception misleads some speculative minds into assigning life to the universe. The universe assuredly exists, but it does not live; its existence can only be identified with life, such as we observe in organisms, by a complete obliteration of the speciality which the term Life is meant to designate. Yet many have not only pleased themselves with such a conception, but have conceived the universe to be an organism fashioned, directed, and sustained by a soul like that of man—the anima mundi. This is to violate all scientific canons. The life of a plant-organism is not the same as the life of an animal-organism; the life of an animal-organism is not the same as the life of a human-organism; nor can the life of a human-organism be the same as the life of the world-organism. The unity of Existences does not obliterate the variety of Modes; yet it is the speciality of each Mode which Science investigates; to some of these Modes the term Life is consistently applied, to others not; and if we merge them all in a common term, we must then invent a new term to designate the Modes now included under Life.
10. In resisting this unwarrantable extension of the term I am not only pointing to a speculative error, but also to a serious biological error common in both spiritualist and materialist schools, namely that of assigning Life to other than organic agencies. Instead of recognizing the speciality of this Mode of Existence as dependent on a speciality of the organic conditions, the spiritualist assigns Life to some extra-organic Vital Principle, the materialist assigns it to some inorganic agent—physical or chemical. Waiving for the present all discussion of Vitalism, let us consider in what sense we must separate organic from all inorganic phenomena.
11. There is a distinction between inorganic and organic which may fitly be called radical: it lies at the root of the phenomena, and must be accepted as an ultimate fact, although the synthesis on which it depends is analytically reducible to a complication of more primitive conditions. It has been already indicated in § [5]. All organisms above the very simplest are syntheses Of three terms: Structure, Aliment, and Instrument. Crystals, like all other anorganisms have structure, and in a certain sense they may be said to grow (Mineralia crescunt), though the growth is by increase and not by modification:[2] the motherlye, which is the food of the crystal, is never brought to the crystal, nor prepared for it, by any instrumental agency of the crystal. Organisms are exclusively instrumental; the organ is an instrument. The structural integrity of an organism is thus preserved through an alimentation which is effected through special instruments. Nothing like this is visible in anorganisms.
The increase of a crystal is further distinguishable from the growth of an organism, in the fact Of its being simple accretion without development; and the structure of the crystal is distinguishable from that of an organism in the fact that its integrity is preserved by the exclusion of all molecular change, and not by the simultaneous changes of molecular decomposition and recomposition. Inorganic substances are sometimes as unstable as organic, sometimes even more unstable; but their instability is the source of their structural destruction—they change into other species; whereas the instability of organized substances (not of organic) is the source of their structural integrity: the tissue is renovated, and its renovation is a consequence of its waste.