Physical change

“ No human power can produce a change in the physical conditions of the earth, or of the air; and if our diseases are connected with those changes, as beyond all doubt a number of them are, they lie above man’s control. ”

“ We shall best understand the probable course of natural selection by taking the case of a country undergoing some slight physical change, for instance, of climate. The proportional numbers of its inhabitants will almost immediately undergo a change, and some species will probably become extinct. We may conclude, from what we have seen of the intimate and complex manner in which the inhabitants of each country are bound together, that any change in the numerical proportions of the inhabitants, independently of the change of climate itself, would seriously affect the others. ”

“ For man has gained new muscles, in his use of the forms and forces of the inorganic world, and has commenced a new process of adaptation, which has already enabled him to extend his kingdom from the tropic to the frigid zone, and which promises to make him to some extent master of the fields of water and air. And his mental experience of wider and wider conditions of nature has produced a new form of physical adaptation—that signified in clothing and habitation. ”

“ But to avoid undue suspension of the argument, I content myself with saying that when the respective effects of gravitation, heat, light, &c., are studied, as well as the respective effects, physical and chemical, of the matters forming the media, water and air, it will be found that while more or less operative on all bodies, each modifies organic bodies to an extent immensely greater than the extent to which it modifies inorganic bodies. ”

“ I was simple enough to think that no one who had as much knowledge of physiology as is to be found in an elementary primer, or who had ever heard of the greatest physical generalisation of modern times—the doctrine of the conservation of energy—would dream of doubting my statement ”

“ And beyond his form no physical progress seems possible, for he fulfills what we conceive to be Nature's design, viz., to husband force by the fullest avoidance of gravity and friction, to decrease weight to the lowest available point consistent with the size and strength necessary to best adapt him to surrounding conditions, and to produce the utmost susceptibility to impression of natural force—to attain a form, in fact, having the greatest excess of available energy, and best adapted to gain experiences of the conditions of nature. ”

“ In the region of natural philosophy progress is no less pronounced and no less striking. It suffices here, however, by way of anticipation, simply to name the greatest generalization of the century in physical science—the doctrine of the conservation of energy. ”

“ And the constantly revolving circle of periodic changes of growth and decay, of life and death, of seed beginning and seed producing—like sunshine and shadow, light and darkness—are opposite points in the circle of electric force and physical life. The growing and dying life-forms intervene between these two points of rest and renewal, of attraction and repulsion, of positive organism and negative diffusion of matter. ”

“ The second class of powers embraces those which we can account for by the universally-known laws of physics. Among these I reckon the mechanism of motion, and the chemistry of the human body, the source of vegetable life. Vegetation, then, and animal mechanism, thoroughly mingled, form the proper physical life of the human body. ”

“ This bodily activity, visible and invisible, is the result of a third mysterious process, more or less continuous as long as life endures, of chemical2 disintegration, decomposition, and oxidation, by which arises the evolution of energy to maintain the heat of the body and the power for mental and physical work. ”

“ When life is prolonged, the fact implies that the combination of actions, visible and invisible, constituting life, retains its equilibrium longer than usual in presence of environing forces which tend to destroy its equilibrium. That is to say, growth, variation, survival, death, if they are to be reduced to the forms in which physical science can recognize them, must be expressed as effects of agencies definitely conceived—mechanical forces, light, heat, chemical affinity, &c. ”

“ In these ways a complicated network of changes arise that are to be referred to ultimate changes in climate, food, health and activity. These causes create types differing in a thousand ways, physical and social. Types are easy to recognize, but hard to measure. ”

“ We proceed to state the dynamical
principles involved in these manifestations, which appear
characteristic of the organism, as follows:—
_The transfer of energy into any animate material system is
attended by effects conducive to the transfer, and retardative of
dissipation._
This statement is, I think, perfectly general. It has been in
part advanced before, but from the organic more than the physical
point of view. Thus, "hunger is an essential characteristic of
living matter" ”

“ In the gradual evolution of energy described on page 316, when a portion rises from physical to chemical, from chemical to vital, or from vital to sentient, it does not remain ever after in the higher condition—there is no immortality on the higher plane. ”

“ The present more or less unstable condition of the circumstances surrounding organic beings, together with the known mutations of climate our planet has undergone in past geological ages, point clearly to the agency of physical conditions as one of the chief factors in the evolution of new forms of life. ”

“ In the history of the evolution of the cosmos, the forces of Nature have appeared successively and suddenly when conditions became favorable. There was a time in the history of the earth when only physical forces existed, chemical affinity being held in abeyance by the intensity of the heat.41 By gradual cooling, chemical affinity at a certain stage came into being—was born, a new form of force, with new and peculiar phenomena, though doubtless derived from the preceding. ”

“ He wished to be shown that changes in form caused evolution in force; that chemical or mechanical energy had, by natural selection and minute changes, under uniform conditions, converted itself into thought. ”

“ There are numerous additional physical variations in planetary life, but all of these differences are wholly matters of anatomical modification, physiologic differentiation, and electrochemical adjustment. ”

“ The various grades of life on our planet are the natural consequences of certain physical processes involved in the gradual transformations of the earth. Conscious life is viewed as conditioned by physical (organic and more especially nervous) processes, and as evolving itself in close correlation with organic evolution. ”

“ But it is certain that man has reacted upon organized and inorganic nature, and thereby modified, if not determined, the material structure of his earthly home. The measure of that reaction manifestly constitutes a very important element in the appreciation of the relations between mind and matter, as well as in the discussion of many purely physical problems. ”

“ What is the whole physical life in that moment but a combination of natural elements to which science gives their names? But these elements, phosphorus and lime and delicate fibres, are present not in the human body alone: we detect them in places most remote from it. Our physical life is a perpetual motion of them—the passage of the blood, the wasting and repairing of the lenses of the eye, the modification of the tissues of the brain by every ray of light and sound—processes which science reduces to simpler and more elementary forces. ”

“ The indispensable preliminary condition of progress has been supplied by the conversion of scientific discoveries into inventions which turn physical energy, the energy of sun, coal, and iron, to account. Neither the discoveries nor the inventions were the product of unconscious physical nature. ”

“ At present, then, all that I can hope is to excite an interest in a topic of much economical importance, by pointing out the directions and illustrating the modes in which human action has been, or may be, most injurious or most beneficial in its influence upon the physical conditions of the earth we inhabit We cannot always distinguish between the results of man's action and the effects of purely geological or cosmical causes. ”

“ Conservation of energy.
Everyday observation shows that, of the bodies which compose the material world, some are in motion and some are, or appear to be, at rest. Of the bodies in motion, some, like the sun and stars, exhibit a constant movement, regular in amount and direction, for which no external cause appears. Others, as stones and smoke, seem also to move of themselves when external impediments are taken away. ”

“ Every department and sub-department of Nature, whether it be the solar system or the earth, or the organic kingdom, or human society, or the human body, is such a system of correlated parts, and is therefore subject to evolution. We can best make this thought clear by examples:
1. Take, then, the human body. This complex and beautiful system of correlated and nicely-adjusted parts may be studied in a state of maturity and equilibrium, in which all the organs and functions by action and reaction co-operate to produce perfect stability, health, and physical happiness. ”

“ As the waves grow when the winds strive with the other forces which govern the movements of the surface of the sea, as the heap grows when we pour corn out of a sack, as the crystal grows when from the surrounding solution the proper molecules fall into their appropriate places: so in all these cases, very much as in the organism itself, is growth accompanied by change of form, and by a development of definite shapes and contours. ”

“ It has also been mentioned that the organism reduces its work of decomposition, gradually adapting itself to the unfavorable conditions of sustenance, and thus meets our efforts to maintain its material equilibrium. ”

“ A skin of some dimension was cast in the 16th century, and another towards the end of the 18th, while, within the last fifty years, the extraordinary growth of every department of physical science has spread among us mental food of so nutritious and stimulating a character that a new ecdysis seems imminent. ”

“ We believe in the Conservation of the physical forces, in the Law of Evolution as it is at present and for a limited past time found to express the facts of nature, and in the fact of the Dissipation of Energy. All this we believe as the scientifically probable view, and we do so on the authority of certain students of physical science, who, having examined the facts, seem to agree upon so much as capable of popular exposition. ”

“ The external conditions of life, as climate and food, &c., seem to have induced some slight modifications. Habit, in producing constitutional differences, and use, in strengthening, and disuse, in weakening and diminishing organs, seem to have been more potent in their effects. ”

“ Although the conditions of the past have required a vast expenditure of physical energy, the activities of the future will make no such demand. Nature’s forces directed by the human will and intellect are already lessening the necessity for an excessive outlay of bodily strength. ”

“ It is manifest, a priori, that since changes in the physical state of the environment, as also of those mechanical actions and those variations of available food which occur in it, are liable to stop the processes going on in the organism; and since the adaptive changes in the organism have the effects of directly or indirectly counter-balancing these changes in the environment; it follows that the life of the organism will be short or long, low or high, according to the extent to which changes in the environment are met by corresponding changes in the organism. ”

“ Could we suppose produced on the present globe some general change of conditions in the sea, on the land, and in the atmosphere—either simultaneously, or by communication from a central area of disturbance —the effects upon organic life might be everywhere manifested, though unequally and variously. ”

“ Now we can readily conceive how an organism, such as the human, in the eternal process of evolution, or more philosophically speaking, adaptation to Nature, being constrained to the use of only the sense of touch or force, for instance, might develop this sense to such a degree of sensitiveness or perfection, that it would be capable of distinguishing the minutest differences in the temperature of a body even at some distance, to a hundredth, or thousandth, or millionth part of a degree. ”

“ Both must be tempered to a condition which will permit and favour continual change, the metabolism which is the essential feature of life.
“When the earth had to be prepared for the habitation of man, a veil, as it were, of intermediate being was spread between him and its darkness, in which were joined, in a subdued measure, the stability and the insensibility of the earth, and the passion and perishing of mankind. ”

“ Changes in the constitution of the air or its pressure, in the composition of the sea or its depth, in the brilliancy of light or the amount of heat, in the inorganic material of a medium, will modify old forms into new ones, or compel their extinction. Birth and death go hand in hand; creation and extinction are inseparable. The variation of organic form is continuous; it depends upon an orderly succession of material events; appearances and eliminations are managed upon a common principle; they stand connected with the irresistible course of great mundane changes. ”