Let us now apply the general laws we have scrutinized, to those beings of Nature who interest us the most. Let us see in what man differs from the other beings by which he is surrounded. Let us examine if he has not certain points in conformity with them, that oblige him, notwithstanding the different properties they respectively possess, to act in certain respects according to the universal laws to which every thing is submitted. Finally, let us enquire if the ideas he has formed of himself in meditating on his own peculiar mode of existence, be chimerical, or founded in reason. Man occupies a place amidst that crowd, that multitude of beings, of which Nature is the assemblage. His essence, that is to say, the peculiar manner of existence, by which he is distinguished from other beings, renders him susceptible of various modes of action, of a variety of motion, some of which are simple and visible, others concealed and complicated. His life itself is nothing more than a long series, a succession of necessary and connected motion; which operates perpetual changes in his machine; which has for its principle either causes contained within himself, such as blood, nerves, fibres, flesh, bones; in short, the matter, as well solid as fluid, of which his body is composed--or those exterior causes, which, by acting upon him, modify him diversely; such as the air with which he is encompassed, the aliments by which he is nourished, and all those objects from which he receives any impulse whatever, by the impression they make on his senses. Man, like all other beings in Nature, tends to his own destruction--he experiences inert force--he gravitates upon himself--he is attracted by objects that are contrary or repugnant to his existence--he seeks after some--he flies, or endeavours to remove himself from others. It is this variety of action, this diversity of modification of which the human being is susceptible, that has been designated under such different names, by such varied nomenclature. It will be necessary, presently, to examine these closely and go more into detail. However marvellous, however hidden, however secret, however complicated may be the modes of action, which the human frame undergoes, whether interiorly or exteriorly; whatever may be, or appear to be the impulse he either receives or communicates, examined closely, it will be found that all his motion, all his operations, all his changes, all his various states, all his revolutions, are constantly regulated by the same laws, which Nature has prescribed to all the beings she brings forth--which she developes--which she enriches with faculties--of which she increases the bulk--which she conserves for a season--which she ends by decomposing, by destroying: obliging them to change their form.