Read CHAPTER X of History of the Intellectual Development of Europe‚ Volume II, free online book, by John William Draper, on



When the ancient doctrine of the plurality of worlds was restored by Bruno, Galileo, and other modern astronomers, the resistance it encountered was mainly owing to its anticipated bearing on the nature and relations of man. It was said, if round our sun, as a centre, there revolve so many planetary bodies, experiencing the changes of summer and winter, day and night bodies illuminated by satellites, and perhaps enjoying twilight and other benefits such as have been conferred on the earth shall we not consider them the abodes of accountable, perhaps of sinful, beings like ourselves? Nay, more; if each of the innumerable fixed stars is, as our sun, a central focus of light, attended by dark and revolving globes, is it not necessary to admit that they also have their inhabitants? But among so many families of intelligent beings, how is it that we, the denizens of an insignificant speck, have alone been found worthy of God’s regard?

It was this reasoning that sustained the geocentric theory, and made the earth the centre of the universe, the most noble of created things; the sun, the moon, the stars, being only ministers for the service of man.

So in that collection of substance which constitutes an animal; whatever may be its position, high or low, in the realm of life, there is a perpetual introduction of new material and a perpetual departure of the old. It is a form, rather than an individual, that we see. Its permanence altogether depends on the permanence of the external conditions. If they change, it also changes, and a new form is the result.

The action of a plant upon the air is therefore the separation of combustible material from that medium. Carbon is thus obtained from carbonic acid; from water, hydrogen. Plant life is chemically an operation of reduction, for in like manner ammonia is decomposed into its constituents, which are nitrogen and hydrogen; and sulphuric and phosphoric acids, which like ammonia, may have been brought into the plant through its roots in the form of salt bodies, are made to yield up the oxygen with which they had been combined, and their sulphur and phosphorus, combustible elements, are appropriated.

Vegetable products thus constitute a magazine in which force is stored up and preserved for any assignable time. Hence they are adapted for animal food and for the procuring of warmth. The heat evolved in the combustion of coal in domestic economy was originally light from the sun appropriated by plants in the Secondary geological times, and locked up for untold ages. The sun is also the source from which was derived the light obtained in all our artificial operations of burning gas, oil, fat, wax, for the purposes of illumination.

From this point of view, animals must therefore be considered as machines, in which force obtained as has been described, is utilized. The food they take, or the tissue that has been formed from it, is acted upon by the air they breathe, and undergoes partial or total oxydation, and now emerges again, in part as heat in part as nerve-force, in some few instances in part as light or electricity, the force that originally came from the sun.

Thus, by the light of the sun, the carbonic acid of the atmosphere is decomposed its oxygen is set free, its carbon furnished to plants. The products obtained serve for the food of animals, and in their systems the carbon is re-oxydized by the air they respire, and, resuming the condition of carbonic acid, is thrown back into the atmosphere in the breath, ready to be decomposed by the sunlight once more, and run through the same cycle of changes again. The growth of a plant and the respiration of an animal are dependent on each other.

It is but little that we know respecting the mutations and distribution of force in the universe. We cannot tell what becomes of that which has characterized animal life, though of its perpetuity we may be assured. It has no more been destroyed than the material particles of which such animals consist. They have been transmuted into new forms it has taken on a new aspect. The sum total of matter in the world is invariable; so, likewise, is the sum total of force.

In the following paragraphs the distinction here made is brought into more striking relief.

“The study of this portion of the mechanism of man brings us therefore in contact with metaphysical science, and some of its fundamental dogmas we have to consider. Nearly all philosophers who have cultivated in recent times that branch of knowledge, have viewed with apprehension the rapid advances of physiology, foreseeing that it would attempt the final solution of problems which have exercised the ingenuity of the last twenty centuries. In this they are not mistaken. Certainly it is desirable that some new method should be introduced, which may give point and precision to whatever metaphysical truths exist, and enable us to distinguish, separate, and dismiss what are only vain and empty speculations.

“Whatever may be said by speculative philosophers to the contrary, the advancement of metaphysics is through the study of physiology. What sort of a science would optics have been among men who had purposely put out their own eyes? What would have been the progress of astronomy among those who disdained to look at the heavens? Yet such is the preposterous course followed by the so-called philosophers. They have given us imposing doctrines of the nature and attributes of the mind in absolute ignorance of its material substratum. Of the great authors who have thus succeeded one another in ephemeral celebrity, how many made themselves acquainted with the structure of the human brain? Doubtless some had been so unfortunate as never to see one! Yet that wonderful organ was the basis of all their speculations. In voluntarily isolating themselves from every solid fact which might serve to be a landmark to them, they may be truly said to have sailed upon a shoreless sea from which the fog never lifts. The only fact they teach us with certainty is, that they know nothing with certainty. It is the inherent difficulty of their method that it must lead to unsubstantial results. What is not founded on a material substratum is necessarily a castle in the air.”

The fibres thus described are of the kind designated by physiologists as the cerebro-spinal; there are others, passing under the name of the sympathetic, characterized by not possessing the investing medullary substance. In colour they are yellowish-gray; but it is not necessary here to consider them further.

It has been said that the vesicular portion of the nerve mechanism is copiously supplied with blood. Indeed, the condition indispensably necessary for its functional activity is waste by oxydation. Arterial vessels are abundantly furnished to insure the necessary supply of aerated blood, and veins to carry away the wasted products of decay. Also, through the former, the necessary materials for repair and renovation are brought. There is a definite waste of nervous substance in the production of a definite mechanical or intellectual result a material connexion and condition that must never be overlooked. Hence it is plain that unless the repair and the waste are synchronously equal to one another, periodicities in the action of the nervous system will arise, this being the fundamental condition connected with the physical theories of sleep and fatigue.

The statements here made rest upon two distinct forms of evidence. In part they are derived from an interpretation of anatomical structure, and in part from direct experiment, chiefly by the aid of feeble electrical currents. The registering or preserving action displayed by a ganglion may be considered as an effect, resembling that of the construction known as Ritter’s secondary piles.

It will not suit my purpose to offer more than the simplest illustration of the application of the foregoing facts. When an impression, either by pressure or in any other way, is made on the exterior termination of a centripetal fibre, the influence is conveyed with a velocity such as has been mentioned into the vesicle to which that fibre is attached, and thence, going forth along the centrifugal fibre, may give rise to motion through contraction of the muscle to which that fibre is distributed. An impression has thus produced a motion, and to the operation the designation of reflexion is commonly given. This reflexion takes place without consciousness. The three parts the centripetal fibre, the vesicle, and the centrifugal fibre conjointly constitute a simple nervous arc.

This principle of dedication to special uses is carried out in the introduction of ganglia intended to be affected by light, or sounds, or odours. The impressions of those agencies are carried to the ganglion by its centripetal fibres. Such ganglia of special action are most commonly coalesced together, forming nervous masses of conspicuous size; they are always commissured with those for ordinary motions, the action being reflex, as in the preceding case, though of a higher order, since it is attended with consciousness.

Of parts like those described, and of others of a higher order, as will be presently seen, the most complex nervous system, even that of man, is composed. It might, perhaps, be expected that for the determination of the duty of each part of such complex system the physiologist must necessarily resort to experiment, observing what functions have been injured or destroyed when given portions have been removed by his knife. At the best, however, evidence of that kind must be very unsatisfactory on account of the shock the entire system receives in vivisections, and accordingly, artificial evidence can, for the most part, be used only in a corroborative way. But, as Cuvier observed, the hand of Nature has prepared for us these very experiments without that drawback. The animal series, as we advance upward from its lowest members, proves to us what is the effect of the addition of new parts in succession to a nervous system, as also does any individual thereof in its successive periods of development. It is one of the most important discoveries of modern physiology that, as respects their nervous system, we can safely transfer our reasonings and conclusions from the case of the lowest to that of the highest animal tribes.

The articulata present structures and a mode of action illustrating in a striking manner the nervous system of man. Lengthwise upon their ventral region is laid a double cord, with ganglia, like a string of beads; sometimes the cords are a little distance apart, but more generally they are coalesced, each pair of ganglia being fused into one. To every segment of the body a pair is supplied, each pair controlling its own segment, and acting toward it automatically, each also acting like any of the others. But in the region of the head there is a special pair, the cephalic ganglia, receiving fibres from the eyes and other organs of sense. From them proceed filaments to the ventral cord, establishing communications with every segment. So every part has two connexions, one with its own ventral ganglia, and one with the cephalic.

It is not difficult to determine experimentally the functions of the ventral ganglia and those of the cephalic. If a centipede be decapitated, its body is still capable of moving, the motion being evidently of a reflex kind, originating in the pressure of the legs against the surface on which they rest. The ventral cord, with its ganglia, is hence purely an automatic mechanism. But if, in making the decapitation, we leave a portion of the body in connexion with the head, we recognize very plainly that the cephalic ganglia are exercising a governing power. In the part from which they have been cut off the movement is forward, regardless of any obstacle; in that to which they are attached there are modifications in the motions, depending on sight or other special senses; obstacles are avoided, and a variety of directions pursued. Yet still the actions are not intelligent, only instinctive. The general conclusion therefore is, that the cephalic ganglia are of a higher order than the ventral, the latter being simply mechanical, the former instinctive; but thus far there is no trace of intelligence.

Such is therefore the process of development of the nervous system of man; such are the powers which consequently he successively displays. His reason at last is paramount. No longer are his actions exclusively prompted by sensations; they are determined much more by ideas that have resulted from his former experiences. While animals which approach him most closely in construction require an external stimulus to commence a train of thought, he can direct his mental operations, and in this respect is parted from them by a vast interval. The states through which he has passed are the automatic, the instinctive, the intellectual; each has its own apparatus, and all at last work harmoniously together.

Is it probable that the individual proceeds in his movement of development under law, that the planet also proceeds in its movements under law, but that society does not proceed under law?

But it is only a part of sociology that we have considered, and of which we have investigated the development. In the most philosophical aspect the subject includes comparative as well as human sociology. For, though there may not be society where actions are simply reflex, there is a possibility of it where they are instinctive, as well as where they are intellectual. Its essential condition being intercommunication, there are necessarily modifications depending respectively on touch or upon the higher and more delicate senses. That is none the less society which, among insects, depends upon antennal contacts. Human society, founded on speech, sight, hearing, has its indistinct beginnings, its rudiments, very low down in the animal scale, as in the bell-like note which some of the nudibranchiate gasteropods emit, or the solitary midnight tapping with which the death-watch salutes his mate. Society resting on instinct is characterised by immobility; it is necessarily unprogressive. Society resting on intellect is always advancing.

But, for the present, declining this general examination of sociology, and limiting our attention strictly to that of humanity, we can not fail to be struck with the fact that in us the direction of evolution is altogether toward the intellectual, a conclusion equally impressed upon us whether our mode of examination be anatomical or historical. Anatomically we find no provision in the nervous system for the improvement of the moral, save indirectly through the intellectual, the whole aim of development being for the sake of intelligence. Historically, in the same manner, we find that the intellectual has always led the way in social advancement, the moral having been subordinate thereto. The former hay been the mainspring of the movement, the latter passively affected. It is a mistake to make the progress of society depend on that which is itself controlled by a higher power. In the earlier and inferior stages of individual life we may govern through the moral alone. In that way we may guide children, but it is to the understanding of the adult that we must appeal. A system working only through the moral must sooner or later come into an antagonism with the intellectual, and, if it do not contain within itself a means of adaptation to the changing circumstances, it must in the end be overthrown. This was the grand error of that Roman system which presided while European civilization was developing. It assumed as its basis a uniform, a stationary psychological condition in man. Forgetting that the powers of the mind grow with the possessions of the mind, it considered those who lived in past generations as being in no respect mentally inferior to those who are living now, though our children at sixteen may have a wider range of knowledge than our ancestors at sixty. That such an imperfect system could exist for so many ages is a proof of a contemporary condition of undeveloped intellect, just as we see that the understanding of a child does not revolt against the moral suasion, often intrinsically feeble, through which we attempt to influence him. But it would be as unphilosophical to treat with disdain the ideas that have served for a guide in the earlier ages of European life, as to look with contempt on the motives that have guided us in youth. Their feebleness and incompetency are excused by their suitability to the period of life to which they are applied.

But whoever considers these things will see that there is a term beyond which the application of such methods cannot be extended. The head of a family would act unwisely if he attempted to apply to his son at twenty-one the methods he had successfully used at ten; such methods could be only rendered effective by a resort to physical compulsion. A great change in the intervening years has taken place, and ideas once intrinsically powerful can exert their influence no more. The moral may have remained unchanged; it may be precisely as it was no better, no worse; but that which has changed is the understanding. Reasoning and inducements of an intellectual kind are now needful. An attempt to persist in an absolute system by constraint would only meet with remonstrance and derision.

Wherever, then, such a want of harmony becomes perceptible, where the social system is incompatible with the social state, and is, in effect, an obsolete anachronism, it is plainly unphilosophical and unwise to resort to means of compulsion. No matter what the power of governments or of human authorities may be, it is impossible for them to stop the intellectual advancement, for it forces its way by an organic law over which they have no kind of control.

The eddy, the ripple, the wave, the current, are accidental forms through which the originally imparted force is displayed. They are all expending power. Their life, if such a term can be used, is not the property of themselves, but of the ocean to which they belong.

Influences which thus metaphorically give life to the sea, in reality give life to the land. Under their genial operation a wave of verdure spreads over the earth, and countless myriads of animated things attend it, each like the eddies and ripples of the sea, expending its share of the imparted force. The life of these accidental forms, through which power is being transposed, belongs, not to itself, but to the universe of which it is a part.

But Europe, and also the Mohammedan nations of Asia, have not received with approbation that view. To them there is an individualized impersonation of the soul, and an expectation of its life hereafter. The animal fabric is only an instrument for its use. The eye is the window through which that mysterious principle perceives: through the ear are brought to its attention articulate sounds and harmonies; by the other organs the sensible qualities of bodies are made known. From the silent chambers and winding labyrinths of the brain the veiled enchantress looks forth on the outer world, and holds the subservient body in an irresistible spell.