But no sooner is matter interpenetrated by that mysterious force which we call life, than our most potent means of investigation suddenly cease to be efficient. Undoubtedly, you may analyse the seed before you sow it, and thus may ascertain that it consists of _carbon_, _hydrogen_, _oxygen_, and _azote_. But with the same elements attempt to recompose your seed, using exactly the same proportions as those you discovered in it; and if you think that your synthesis has been successful, ensure that your grain, once confided to the earth, shall become a focus of divers movements, giving birth below to the ramifications of the root, terminated by the spongioles,--above, to the ramifications of the stem, garnished with leaves, flowers, and fruits; finally, ensure that this aggregate of organs, multiplying millions of times the weight and volume of the seed, shall always and exactly reproduce the same type or the same species. If, with your apparatus,--if, with the means at the disposal of humanity,--you should succeed in achieving all these marvels of nature; then perhaps you might settle the great problem of what life is,--whether an independent force, or a simple modification of an universal force, of which heat, light, electricity, and magnetism, will be but different modes of manifestation. And yet, even in such a case, you must not boast too loudly of your power; for you will find it necessary to turn and return the term you have arrived at, in every direction; nor will it furnish you with the relation or the cause of the formidable progression whose _alpha_ and _omega_, whose beginning and end, escape us so absolutely. Whence, in all its interminable metamorphoses, whence comes life? Whither goes it? Were our world to perish, its ruins would not cease, in their apparently disordered movements, to obey the law of universal gravitation: they would so group themselves as to form other worlds, resembling the system of which they were anteriorly the framework. But this force in no wise tells you why, when, and how life will make its appearance on these spheroids of revolution, which, in their state of ponderation, are attracted in the direct ratio of their masses and in the inverse ratio of the square of their distances. * * * * * This is not all. Man justly plumes himself on having arrived, by a process of experiment, at the following irrefragable axiom: that "the matter which serves for the movements of life renews itself, while the mould or form remains." You may even affirm, without appearing too adventurous, that the innumerable whirling globules which enter into the composition of the human blood are so many microscopical individuals, each with its own proper life,--infinitesimal forms which are born, and move to and fro, and disappear, and are renewed, without the individual--whose aggregate they perform--having any consciousness of all this activity.