in short, each species was, as it were, reconstructed from a single one of its component elements." It is hardly necessary to say that, since this first successful experiment, the same principles have been more thoroughly investigated and extended with the same success into every department of fossil organic nature. The results which have crowned the labors of such men as Agassiz, Ehrenberg, Kaup, Goldfuss, Bronn, Blainville, Brongniart, Deshayes, and D'Orbigny, on the continent of Europe, and of Conybeare, Buckland, Mantell, Lindley, and Hutton, and eminently of Owen, in Great Britain, although sustained by the most rigid principles of science, are nevertheless but little short of miraculous; and they demonstrate most clearly the identity of anatomical laws, in all ages, among animals and plants of every size and character, from the lofty lepidodendra and sigillaria to the humblest moss or sea-weed, and from the gigantic dinotherium, mastodon, megatherium, and iguanodon, to the infinitesimal infusoria. _In the sixth place, physiological laws have always been the same upon the globe._ That death has reigned in all past ages over all animated tribes, as it now reigns, so that in that war there has never been a discharge, I need not attempt formally to prove. For the preserved and petrified relics of all the former races, that now lie entombed in the rocks, furnish a silent but impressive demonstration of the former triumph of that great physiological law, which is stamped by the signet of Jehovah upon all existing organic natures--_Dust thou art, and unto dust shalt thou return._ Scarcely more necessary is it to attempt to show that the same system of reproduction for filling the chasms which death occasions, and which is now universal in the animal and vegetable kingdoms, has always existed. Indeed, such a system is a necessary counterpart to a system of dissolution. And we find the same phases to this reproductive system in ancient and in modern periods. Organic remains clearly teach us that there have always been viviparous as well as oviparous creatures, and gemmiparous as well as fissiparous animals and plants. The second great physiological law of existing nature has, then, always been the same. The character of the nourishment by which animals and plants have been sustained has never varied. The latter have ever been nourished by inorganic, and the former by organic, matter. Some animals have ever fed upon the flesh of other animals, as their petrified remains, enclosing the masticated and half-digested fragments of other animals, testify. Other tribes have fed only upon herbs or fruits; and some were omnivorous; just, in fact, as we find the habits of existing animals.