and the continued radiation of heat into space, and the loss of the forces of the elements by radiation during their chemical union. Without a continued supply of force all motion would cease, both in the inorganic and organic worlds.

The great force which moves the crude sap of plants from the roots to the leaves, from cell to cell, in opposition to the force of gravity, is endosmose, which is itself dependent upon chemical actions, and the varying densities of the contents of the cells, both of which depend ultimately upon the forces of the sun. After the inorganic elements and moisture have been supplied, the luxuri ance and perfection of plants depend upon the intensity of the forces of the sun.

The truth of this proposition may be established by a reference to the distribution of plants upon the surface of our globe, and upon mountains, which rise to a great height in tropical countries.

Whilst in equinoctial and tropical countries, where a sufficient supply of moisture combines with the influence of heat and light, vegetation appears in all its magnitude and glory; on the other hand, in polar regions, and upon the summits of lofty mountains, all the more complicated forms of vegetable existence disappear, and lichens and microscopic plants take the place of the majestic forests and impenetrable jungle. In the tropics the lowest orders of plants are comparatively rare; whilst in the polar regions, and upon the summits of mountains, they form almost the entire vegetation.

The strength and activity of animals depend upon the development of the apparatus by which the elements for chemical change are distributed, and the forces resulting from these chemical changes applied, and a free communication between the different systems of organs kept up. The development of the apparatus depends upon the directive influence of the vital force.

The truth of these propositions may be clearly demonstrated by a comparison of the phenomena and anatomical structures of the different species, genera, orders, and classes of animals. Thus, the sluggish, feeble, cold-blooded animal is such, not from any peculiarity of the elements or forces of its structures, but from the imperfect development of the structures and apparatus by which the elements of chemical change are distributed, and the forces resulting from these changes applied. The forces of an animal with imperfectly developed lungs and circulatory apparatus are necessarily feeble, because the apparatus for the introduction and

distribution of the great agent of chemical change (oxygen) are defective in their action.

In the animal, as in the plant, and as in the universe, there is no creation of force independent of the Creator. The geographical distribution of plants, and the relations of animals to the forces of the sun (surrounding temperature), demonstrate conclusively this proposition. The independence of higher animals of surrounding cold (absence of heat or force) is due solely to the fact that they can receive and distribute rapidly the materials necessary for the development of the physical, chemical, and nervous forces. As the external temperature diminishes, the internal chemical changes correspondingly increase. If, however, the external heat diminishes to a point at which the heat lost by radiation from the surface of the body of the living being is greater than that developed by the greatest possible combustion, the warm-blooded animal will be reduced to the condition of a sluggish cold-blooded animal, and finally lose all motion and life. The distinction, then, between cold and warm-blooded animals, drawn from their temperature and corresponding forces, is relative and not absolute.

As far, then, as the knowledge of man extends, the great law of the indestructibility of force, and the great law that action and reaction are equal, are applicable to all phenomena, inorganic and organic.

Physical and chemical forces exist independently of the vital force; the vital force, on the contrary, cannot exist and manifest its peculiar effects without matter and the physical and chemical forces; the acts of development, nutrition, secretion, and excretion, and propagation, which are peculiar to plants and animals, are resultants of the action of the physical and chemical forces upon matter, under the guidance of the vital force, which is incorporated with and presides over every molecule of living organized matter, and directs all its physical and chemical changes, so that amidst innumerable and unceasing changes the individuality of every organ, apparatus, and animal is preserved.

As the germination and development of vegetables and animals, and the maintenance of their life actions, depend essentially upon the properties of matter, upon the relations of matter to the sun and fixed stars, and upon the correlation of the vital, chemical, and physical forces, it is evident that the study of complicated, highly developed plants and animals involves the consideration of their origin, development, structure, and relations to exterior bodies-involves the consideration of the chemical and physical properties of the elements, and combination of elements

entering into their constitution, and the relations of the constituents of their bodies to the surrounding medium-involves the consideration of the relations of the vital, chemical, and physical forces, and intellectual and moral faculties-involves the consideration of the relations of ani mated beings to the forces and arrangements of the sun, and planets, and fixed stars.

The history of the origin, development, and distribution of plants and animals, as revealed by the records upon the solid rocks; the geographical distribution of the plants upon the surface of our globe at the present time; the geographical distribution of animals, and the relations of animated existence to the surrounding medium and external forces as revealed in the correspondence of the internal structures and forces with the arrangements and chemical relations of the elements and the rapidity of the chemical changes, demonstrate that the most simply constructed plants and animals are more widely distributed over the surface of our globe, and the conditions. of their existence more general and less complicated than the more highly developed plants and animals; demonstrate that as we rise in the scale of animal and vegetable existence, the phenomena of life become more complex and less general, and the conditions of their existence more complicated and restricted.1

true.

1 The truth of these propositions may be illustrated in a forcible manner by the relation of vegetable and animal existence to the distribution of the forces of the sun upon the surface of our globe. Thus, as a general rule, after the inorganic elements and moisture have been supplied, the luxuriance and perfection of plants depend upon the intensity of the forces of the sun. The more complicated and perfect the vegetable structures, the closer is their dependence upon the proper supply and balance of the physical forces. The converse of this proposition is also The truth of these propositions may be established by references to the distribution of plants upon the surface of our globe, and upon mountains which rise to a great height in tropical countries. Whilst, in equinoctial countries, where a sufficient supply of moisture combines with the influence of heat and light, vegetation appears in all its magnitude and glory; on the other hand, in polar regions, and upon the summits of lofty mountains, all the more complicated forms of vegetable existence disappear, and lichens and microscopic plants take the place of majestic forests and impenetrable jungles. In the tropics the lowest orders of plants are comparatively rare, whilst in polar regions and upon the summits of mountains they form almost the entire vegetation. The plants which first form upon barren rocks, and lava streams, and coral islands, are those of the most simple organization. The simply organized lichens covering the bald-granite rocks are familiar to every resident of a primitive region. Along the sides of Etna, Ischia, Vesuvius, and other volcanoes, lava streams are seen stretching in all directions, which have flowed down like rivers. These lava streams are of different ages, and many of them were formed within the memory of man. An investigation

An examination of the origin, development, structure, and relations of all vegetables and animals, commencing with the

of these lava streams affords an opportunity of determining the gradual distribution of vegetables. Some are still naked, others have only a few plants scattered here and there in hollows and crevices, and in others the decaying plants are forming a soil. According to the observations of Prof. J. F. Schow, the plants which first settle upon the naked lava, and form a soil for the more complex, are especially those lower and simply organized plants, called lichens, Certain succulent and fleshy plants, as the Indian fig (opuntia vulgaris), which are nourished chiefly by the carbonic acid and aqueous vapor of the open air, absorbed by the stem and leaves, are also amongst the earliest inhabitants of the lava streams. Geology also teaches that the lower orders of plants appeared first upon our globe.

As the luxuriance and perfection of plants depend upon the temperature of the surrounding medium, and the intensity of the forces of the sun; so also the perfection of the nervous system, and of all the organs and apparatus, and the activity and intelligence of animals, correspond, in a great measure, to the rapidity of the physical and chemical changes going on in the molecules of their bodies, and to the relations of the physical, and chemical, and vital forces, and to the temperature which they are able to maintain, regardless of that of the surrounding medium. As the chemical changes become feeble, and the temperature of animals descends and becomes dependent upon that of the surrounding medium, they become more simple in their organization and mode of life, the conditions of their existence become less restricted, and they resemble closely the simple forms of vegetables, and in the twilight of existence we can scarcely distinguish between the lowest forms of plants and animals.

If we examine the relations of the physical and chemical agents to the animal kingdom, we will find that the most simply constructed animals, many of which are devoid of a nervous system and special organs of sense, as the infusoria, are, as in the case of the simply organized plants, the most widely distributed over the face of our globe, and are at the same time far less dependent for their existence upon the temperature of the surrounding medium.

Infusoria occur in immense numbers in every situation: in stagnant pools, in marshes, in mud of rivers, in peat earth, twenty feet below the surface; in the structures and fluids of living animals and vegetables, in putrefying organic matter, in the bed and waters of the ocean, in snow, in ice, and in boiling springs.

Sir John Ross, in the year 1840, picked up some brash ice of a brown yellow color in the Arctic regions, not far from Mount Erebus, which was supposed to contain aluminous matter, ejected in fine ashes from the volcano. Specimens were brought home in sealed glass vessels, and forwarded to M. Ehrenberg.

This microscopist found the coloring matter to consist of myriads of infusoria, almost the whole of which reached Berlin in 1844, in a living state. Here we see that these microscopical animals, after having been frozen and thawed out, lived without food for four years. Certain species of these animalcules have been found living and propagating in boiling springs, and some of them have been observed to recover after drying in vacuo along with chloride of calcium and sulphuric acid for twenty-eight days, and after exposure to a heat of 2480. The infusorial animals were created at an early geologic period, and a large number of the fossil species, which compose the polirschifer and semi-opal of Bilin, are found at the present time living and propagating in the seas and oceans. The infusoria form a chain

simplest, and ending with the most complicated, leads us to the summit of the pyramid upon which stands man-governed by all the astronomical and chemical and physical laws of inorganic bodies, and comprehending within himself all organic naturearising in common with plants and animals, from the organic cell, and like them, passing through various stages of developmentendowed in common with all vegetables and animals, with vital force-possessing in common with all animals, and in contradis tinction to vegetables, a nervous system endowed with special sensibilities, relating the intellectual faculties to the exterior world, and relating the various organs and apparatus to each other, in such a manner that, amidst an innumerable number of complex actions, unity and harmony result-an organism composed of inorganic elements, prepared and grouped into definite compounds

connecting the organic life of distant ages of the earth, and demonstrating conclusively that the distribution of animals, and the power to survive physical changes, depends upon their development.

The simpler the structures, the feebler the vital, nervous, and physical forces, the less complicated the conditions of existence. The gelatinous medusæ (gelly fishes) occur in such vast numbers in the cold Greenland sea, that they impart an olive green color to the sea, rendering the water dark and opaque, in comparison with the ordinary cerulean hue. Cold-blooded vertebrate animals, although more highly organized than invertebrate animals, still show remarkable powers of enduring extremes of heat and cold without death. Fish may be frozen and again thawed out without a destruction of life. The rapidity with which the absence of heat is attended with loss of sensibility and death, is directly proportional to the development and perfection of vertebrate animals.

The relations between the physical, chemical, and vital forces are strikingly exhibited in certain cold and warm-blooded animals, which become torpid or hybernate during the winter season. In this state all the chemical and physical actions are of the most sluggish character. The heart scarcely beats, the frequency and force of the action of the heart and flow of the circulation is greatly diminished if not entirely stopped. The amount of carbonic acid thrown off from the lungs is greatly diminished, and all the chemical and physical changes of the elements of the tissues, and fluids, and organs of these animals are retarded. If the temperature of a warm-blooded animal be reduced, in like manner all its physical, chemical, and vital actions will be depressed, and the active animal will be reduced to the condition of a sluggish cold-blooded animal, and death will rapidly ensue. is, however, this great difference between the cold and warm-blooded animal—the conditions of the existence of the latter are far more restricted than those of the former. The chemical changes of the cold-blooded animal are slow, and it can exist without food for weeks and months, whilst a few days' starvation is fatal to the warm-blooded animal. These facts demonstrate conclusively that the conditions and phenomena of life are complicated and restricted, in exact accordance with the development and perfection of the organs and tissues of animals, and the rapidity of the chemical and physical changes of the molecules of their bodies.

There