Читать книгу A Review of the Systems of Ethics Founded on the Theory of Evolution - Cora May Williams - Страница 25

Rolph thinks Spencer's theory awakes the conjecture that it was not first arrived at through investigation, but rests upon a preconceived opinion, as do to a greater or less extent all theories on this subject. It seems as if the author had first attached himself to that theory which best accorded with his scientific bias, and then tried whether this theory might be proved or supported by facts of biology and psychology. One might surmise, from the very skilful, but often too artificial argument, that the author pursued the following train of thought. Pleasure, and indeed the greatest possible pleasure, is the end of endeavor in the organic world, that is, the psychical cause of endeavor. May it not also be the physical cause?

Rolph answers this question with a denial, and endeavors to show that the taking of food has its cause in the insatiability of all organic substance. The theory of Spontaneous Generation contains nothing impossible or improbable; is, on the contrary, a necessary logical assumption not to be disproved by the mere result of experiment under conditions of the laboratory. It is easy to imagine that organic elements, which are to be found in great quantities in inorganic nature, may come together by chance, or rather in the natural order of things, to the formation of protoplasm.

The movement of these masses of protoplasm seems, at first glance, to set the law of gravitation at defiance, but we may answer that an ascending balloon might seem, to an uninstructed observer, to do the same, although its movement is merely the natural result of that force; it is not necessary, therefore, to assume a free inner motive, the soul, as the cause of the one motion or the other. The first assimilation of food has its beginning in the process of endosmose and exosmose, in which the protoplasm, as in general the denser fluid, increases in volume, taking up more than it gives out; the process occurring, in detail, according to the special relations of attraction in the parts. The organism always takes up the greatest amount possible under the circumstances, exactly as, in the inorganic world, water takes up the greatest amount possible of salt or any other soluble substance; the growth of a crystal, and the oxidation of iron are illustrations of the same principle. Of the limit of this capacity to take up new matter into the organism we know nothing; all recent experiments go to show that the organism is capable, under propitious circumstances, of an enormous receptivity, such as, under natural conditions, it never reaches. The lower animals feed continually, and their whole lives are passed in this employment. In plants the tendency is seen still more clearly. Experiments with electric, violet, and ultra-violet light show an enormous growth in plants exposed to its action. But this can be only an indirect growth, namely, the exorbitant acceleration of organic change and assimilation. This fact is proved by experiments turning on increase of warmth in soil; from which is seen to result an unusual development of that part of the plant to which growth is especially directed at the time. When the warmth of an incubator is increased, the animal organ especially engaged in development at the time is affected in like manner. So that we may assume that the organism is capable of responding to every demand that nature makes upon it under normal conditions; and since the greatest possible assimilation under the existing conditions is thus removed from the control of the creature, the latter appears practically insatiable. This insatiability must appear to the observer an inner impulse of the organism, an effort towards increase of nourishment. It may be called mechanical hunger in distinction from psychical hunger, of which it is the basis. It is not necessary to take into consideration, in the question as to the degree of assimilation possible, the amount of excretion of substance by the organism; we must, on the contrary, assert that this is dependent upon the amount of assimilation. The measure of growth depends, therefore, on the degree of assimilation of new material. This degree, however, like the degree to which the matter may be dissolved in a liquid in the case of inorganic matter, is especially affected by light and warmth. The creature which comes into existence in the sun will experience a decrease of organic change when placed in the shade; and the creature which comes into existence in the shade will experience an increase of such change under the influence of the sun, a decrease again with a return to the shade. This decrease means hunger—harm. Experiments with zoöspores throw an interesting light upon these relations. They show that the zoöspores, although suited to very different degrees of light, all shun darkness. Although when in the light they soon come to rest, divide, and copulate, they remain, in the darkness, in a state of continual unrest and motion. They grow so thin "that they almost excite pity" (Strassburger), and finally perish of hunger. Only such zoöspores as are distinguished by sex and copulate come to rest, or those of such sorts as prey upon others. It is easy to perceive that the unrest of the zoöspores in the darkness springs from lack of nourishment, from hunger; they seek feverishly for the light, without which assimilation follows with insufficient energy to satisfy need and render life possible. In darkness, copulation alone can do this; copulation takes, then, the place of normal nourishment.

Or let us consider the case of an organism which has originated in the shade. Heat, as we know, increases chemical change, in inorganic as well as organic matter; it hastens the disintegration of certain compounds, and alone renders it possible in many cases. In general, we may assert that increase of temperature within certain limits increases assimilation; that is, capacity to assimilate. Therefore, if an animal is placed in the sun, its capacity, that is, its need, to assimilate is increased, although assimilation is much more energetic than before. Need to assimilate or hunger is, therefore, dependent upon the supply of food, although, doubtless, also on other conditions, especially those of light and temperature. If this is true, the hunger of a simple organism that assimilates energetically must be more intense than that of one which assimilates slowly, in spite of the consumption of an enormous quantity of food in the case of the former. Botanists know (Sachs, "Lehrbuch der Botanik," p. 613) "that growth may be so hastened by too high a temperature that assimilation (especially under scanty light) does not suffice to provide the necessary material for it. The transpiration of the leaves may be so increased that the roots cannot repair the loss. And on the other hand, a too low temperature of the soil may so diminish the action of the roots that even a small loss by transpiration cannot be repaired."

At what stage of organization psychical hunger is added to mechanical hunger, or whether it may be identified with it, we cannot say. In any case, the former appears exceedingly early, for excitations of hunger may be observed in creatures very low in the scale of being. Certainly hunger is never absent where there is movement.

Hunger, a sense of pain, is, therefore, the first impulse to action.[58]

With a like effort in the attempt to obtain food, that organism will be best nourished which commands the best means of obtaining and preparing its food—the best apparatus for the seizure and grinding of food, and the best salivary gland. And finally, greater surface of skin, of lungs, of gills, or of intestines, causes greater capacity for assimilation, and since this surface is increased by cell-division or propagation, the capacity of the organism for assimilation grows with its capacity of propagation.[59] Protoplasm is never entirely homogeneous, and we must suppose some difference even in the beginning; such difference is, indeed, fundamental through the very composition of protoplasm from the four fundamental elements, and this or that other element. These different elements must be held together by forces of attraction, and the direction of these forces must have some common centre represented by some differentiation of the protoplasm, whether as clearer spot, or as nucleus. This spontaneously generated organism, neither animal nor plant, is nourished, as we have seen, by diffusion, by the transformation of inorganic into organic substance. The lowest organisms possess no definite organs for taking food; they manifest, however, phenomena of movement which are exactly like those of the animal organism, for they appear unconditioned and hence voluntary. Locomotion is, in the lowest animal forms, the only means of obtaining nourishment. The amœba surrounds and takes in whatever is by chance met with. Animals a little higher in the scale swim about and seek their food; or, remaining in one place, they cause, by means of cilia, a movement of the water towards a certain part of the body, a sort of mouth where the protoplasm is open and can take up the prey in the same manner as does the amœba. Ascending the scale of life, we find more and more complicated apparatus for the seizure of food, for its preparation and digestion, and the beginning of a nervous system, first as the differentiation of certain muscle-cells, then in connection with a special sense, that of hearing. If we assume any pleasure to be connected with the earliest acts of assimilation, it must be that of the satisfaction of a want, the stilling of pain in the form of hunger.