Problems of Life and Mind. Second series by George Henry Lewes (best contemporary novels TXT) 📕

This bioplasm is the germinal matter out of which, by a process of dying, arise the tissues and humors constituting the formed material—these, with the pabulum which feeds the germinal matter, being all dead material. The germinal matter itself, though living, only lives because there is temporarily associated with it that Vital Force of which we have already spoken (§ 14). In virtue of this association, a particle of matter not exceeding the one hundred-thousandth of an inch in diameter is said to be alive; and, presumably, to contain within it all those manifold powers which the term Life condenses. The pabulum brought under the influence of this Vital Force is transformed into germinal matter which, escaping from this mysterious influence, dies into tissue. Muscle-fibres and nerve-fibres are thus not living parts, nor are their actions vital. So that, to be consistent, we must not speak of the organism as living, but as a dead structure produced by the Vital Force, and set in action by the aid of scattered bits of germinal matter. He has not, I think, stated whether each of these bioplasms has its own Vital Force, so that the organism is the theatre of millions of Vital Forces; or whether it is one Vital Force which animates the whole organic world of plants and animals. But nothing can be less equivocal than his position respecting the lifelessness of every part of the organism except the germinal matter.

69. The germinal matter may be selected as the primary stage of the formed material, the initial point of growth, and thus stand for the pre-eminently distinctive centre of Nutrition; but were we to limit all Nutrition to the germinal matter, as defined by Dr. Beale, and deny the co-operation of all the formed material, we should still not be justified in restricting Life to simple Nutrition. We cannot exclude such phenomena as those of Sensation and Motion, nor can we assign these to the germinal matter.23 To suppose this, would be equivalent to saying that the steam which issues from a teakettle is capable of the actions of a locomotive engine. The steam from the kettle is like the steam from the boiler, it has molecular energy, and by this will co-operate in the production of mechanical work, if the mechanism be adjusted to it. The molecular energy of the protoplasm in muscular fibre may be indispensable to the movements of the muscles, but these, and not the protoplasmic movements alone, are muscular contractions. An hypothesis, therefore, which is obliged to declare that muscle-fibre and nerve-fibre are not living, even when active in the organism, seems to me defective at its base. If we view these apart from the organism, they may, like all the other formed materials, be regarded as dead; and no one doubts that epidermis, nail, horn, hair, and bone are dead in this sense, that they cannot live independently, and do not reproduce themselves. But so long as even these form constituents of the living organism, they also are living (§ 42).24 It is only by a misconception of the analytical artifice that so simple a truth could have been missed.

70. But this misconception meets us at many a turn. The Vitalist hypothesis of an extra-organic agent of course refuses to regard Life as the expression of all the co-operant conditions; and even opponents of that hypothesis often fall into the same error of principle, when they attempt to explain Life by localizing it in the cells; which is simply a morphological substitution for the once popular doctrine that only the vascular parts were organized, and every part destitute of blood-vessels was dead. This idea seemed supported by the facts of the most highly vascular parts being the most vital, and of a parallelism existing between the vital activity of those organs which when injected seemed almost entirely composed of blood-vessels, as the liver and brain, and those which showed scarcely a trace of vessels, as cartilage and bone; it seemed supported also by the appearance of blood-vessels in all new formations, and by the idea of the blood as the nutrient fluid. Then came the cell-doctrine, and the belief that the cell was the really ultimate morphological element—which may be true—and that “here alone there is any manifestation of life to be found, so that we must not transfer the seat of vital action anywhere beyond the cell,”25—which is very questionable.

71. We have already seen that the cell is an anatomical element, or organite; the organism is but an aggregate of organites and their plasmodes. But Biology, which deals with the organism as a whole, and with functions which are the resultants of all the vital properties, must not be restricted to any single factor, however important. It would assuredly be deemed absurd to say that diamond rings and lead-pencils were the same, because the diamond and the plumbago, which are the specific elements of each, are both the same chemical element,—carbon. The substance is really different in diamond and plumbago, is different in properties, and is, in rings and pencils, united with different substances into objects having very different properties. Whatever analysis may discover as to the identities of organic structures, we cannot explain a single vital phenomenon without taking into account the three terms, Structure, Aliment, and Instrument; and whenever a cell is said to be the seat of vital action, these three terms must be implied. In Dr. Beale’s hypothesis the restriction is carried to its extreme; not content with the cell, he withdraws vital action from the cell as a whole, assigning it to the protoplasm and nucleus—cell-contents and cell-wall being, in his view, dead. If it be true that the protoplasm is alone concerned in Nutrition, yet Nutrition is not Life. Occupied mainly with formative processes, it leaves other indispensable processes to other parts. He instances the removal of all the tissues during the metamorphoses of insects:—“new organs and textures are laid down afresh and developed ab initio, instead of being built up upon those first formed.” But to show how he restricts the idea of Life, he adds: “Such complete change, however, necessitates a state of existence during which action or function remains in complete abeyance.”26

The muscles and nerves which are instrumental in this functional life are said to be dead. It is true that the muscle-fibre does not develop fresh fibres. But it is equally true that the protoplasm of muscle does not alone execute muscular contraction. Each has its special office. Hence I reject the idea that formed material is dead. He further says “formed material may be changed, it cannot change itself.” The antithesis is doubly inexact: 1°, nothing changes itself, but only yields to pressure, or reacts on being stimulated; and 2°, all the evidence at hand is against the notion that the formed material is not the seat of incessant molecular change; it is wasted and repaired molecule by molecule. Kölliker properly protests against the growing tendency of histologists to deify protoplasm, and to make it the sole seat of vital changes, the cell-wall and cell-products having also, he says, their physiological importance. It is manifestly erroneous to deny vital changes to the red blood-corpuscles on the ground of their no longer containing germinal matter.27

72. The analytical view may separate certain parts as active, and other parts as passive, and thus regard the cells as the seats of vital activity, the intercellular substance as merely accessory and instrumental; but the real or synthetical view must recognize both parts as equally indispensable, equally vital. Take cartilage, for instance, with its enormous preponderance of intercellular substance (formed material), and consider how absolutely impossible any of its uses would be were it reduced to the germinal matter of its corpuscles! And so of all the tissues.

73. If formed material is not to be excluded from the living parts of the organism, neither is the plasmode, out of which the germinal matter arises, since here we have the nutritive changes in their highest activity; and because the property of Nutrition is here most active, the other property of Development is in abeyance. Dr. Beale holds that pabulum necessarily becomes germinal matter; but when we come to treat of Nutrition it will appear that this is not more true than that Food necessarily becomes Tissue: some of it does; but much of it is used up for heat and other purposes.

74. What is true and important in the distinction between germinal matter and formed material is, that from the former onwards there is a gradual process of devitalization, the older parts of every organite and tissue approaching more and more to the state of inorganic matter. But to show how vain is the attempt to restrict Vitality to any one out of a complex of co-operant factors, we might set up a chemical hypothesis to the effect that Vitality depends on phosphates, and with it explain the phenomena quite as well as with the hypothesis of germinal matter. For not only is it found that the productive quality of a soil depends on its richness in phosphates, but, as Lehmann has shown, wherever cells and fibres make their appearance phosphates are found, even in the lowest organisms, which, however, contain but little. Phosphates abound in seeds and ova, in muscles and ganglia, and are deficient in the woody parts of plants and the elastic fibres of animals. The infant absorbs phosphates in large quantities and excretes them in small quantities. Nervous activity is accompanied by the consumption of a third more phosphorus than accompanies muscular activity. Phosphates are among the most energetic of organic stimulants. But who would endow the phosphates with Vitality, on the ground of their indispensable presence in all vital processes?

75. Life, as we saw, is the expression of the whole organism. Many of the parts are incapable of manifesting any vital phenomena except in connection with all the rest; and of those parts which may be separated from the organism and continue to manifest some vital phenomena, none are capable of manifesting all. When the connexus of the parts is destroyed the organism is dead. Long after that cessation which we call Death, there are still evidences of Vitality in some of the parts: the heart will continue to beat, the glands will secrete, the hair will grow, the temperature will still be above that of the surrounding medium, the muscles will be excitable; these vital properties are the activities of organized substances, and so long as the state of organization is preserved they are preserved; but the Life, which is the synthesis of all the vital properties, vanishes with the destruction of that synthesis.

76. May we not generalize this, and say that every special form of existence, organic or inorganic, is determined by the synthesis of its elements? Atoms are grouped into molecules, molecules into masses, masses into systems. Out of the textureless germinal membrane and the yolk, with no additions from without except oxygen and heat, are developed all the textures and organs of the chick; and this chick weighs no more than the egg out of which it was evolved. The development has been a succession of syntheses—epigenesis upon epigenesis. We may, if we please, regard each organite, as it appears, living its separate life, and each tissue its separate life; but we must not confound under the same symbol modes of existence so widely different as the activities of an organite, and the activities of an organism constituted by millions of organites.

77. If therefore we cannot restrict Life to the processes of Nutrition, Dr. Beale’s hypothesis, whatever value it may have as explaining histogenesis, is quite unacceptable. Neither Vital