14 INDEPENDENCE OF THE HIGHER ANIMALS OF EXTERNAL AGENTS. 



pation is complete ; for into his hand Nature has committed a control of the imponder- 

 able principles. It matters not whether it be in the torrid zone or in the frigid, he tem- 

 pers the seasons by his intellectual power ; he resorts to every artifice of clothing, or 

 to the warmth of fire ; he dissipates the natural darkness by artificial light. Devel- 

 oped by civilization, he is no longer a prey to natural accidents ; if the harvests of his 

 own country have failed him, his hands have created commerce, which brings him an 

 abundance from distant places. Unlike even those races which are next below him, and 

 which instinctively aim at the result he so perfectly accomplishes, he does not wait 

 upon the gifts of Nature, but compels her to minister to him. When they are oppress- 

 ed by hunger, whole tribes of fishes migrate in the sea, and innumerable flocks of birds 

 direct their flight to distant countries ; but civilized man, without calling into action 

 his own locomotive powers, puts his arm across the globe, and satisfies his wants. 



39. What, then, are the final impressions left upon our minds by these general con- 

 siderations ? They teach us that life never occurs except in regions to which the im- 

 ponderable agents can have access, an observation which is equally true of vegetable 

 and of animal forms ; that elementary organization directly or indirectly arises from 

 the plastic agency of those all-pervading forces. Whether we consider the organic or 

 inorganic world, all things around us are in incessant changes changes which result 

 from the fixed operation of invariable laws ; that, of the successive tribes of beings 

 which have peopled our earth, each series may be regarded as expressing the general 

 relation of all physical agents at the time of its existence, the brilliancy of the sun, the 

 pressure of the air, and other such conditions ; for we see that, between those condi- 

 tions and the organization of the structures considered, there are fixed relations ; that 

 in the more highly complicated forms of beings, mutations more readily take place, and 

 in all, time enters as an element ; that in the same way that whole races have disap- 

 peared from the face of the earth, and have become extinct, so, also, do individuals die 

 and atoms change ; that, whatever motion is accomplished, or whatever change is brought 

 about, there is a consumption of material or an expenditure of force ; that, as the sur- 

 face of the earth is continually remodelled by physical agents, so are the vicissitudes 

 through which organized forms pass determined by physical powers, and bring about 

 physical ends. The passage of a comet, never more to return, in a hyperbolic orbit past 

 the sun, is a result of the same general law that keeps a planet revolving in repeated 

 circles the extinctions of races which have heretofore taken place, or which are going 

 on before us, are not brought about by a direct intervention of supernumerary forces, 

 but are the constant result of those which are always in action. If, moreover, our 

 thoughts are directed to the relations which exist between climates and the character 

 of races, the distribution of vegetables and animals ; if we observe the antagoiiizatiou of 

 these great classes in the result of their vital processes, their position as respects the at- 

 mosphere, the control which astronomical events possess over everything, the action 

 which currents in the air or currents in the sea exercise over the distribution of anima- 

 ted forms, and even over the well-being of man, we surely shall have but little difficulty 

 in understanding that, as in the inorganic world, so also in the world of organization, 

 those all-pervading forces which natural philosophers and chemists recognise are con- 

 stantly employed. 



