The woody fibre of the Pine-trees has had the same structure from the Carboniferous age to this day, while their mode of branching and the forms of their cones and leaves have been different in each period according to their respective species.  The combination of rings, the structure of the wings, and the articulations of the legs are the same in the Cockroaches of the Carboniferous age as in those which infest our ships and our dwellings to-day, while the proportion of their parts is on quite another scale.  The tissue of the Corals in the Silurian age is identical in chemical combination and organic structure with that of the Corals of our modern reefs, and yet the extensive researches upon this class for which we are indebted to Milne Edwards and Haime have not revealed a single species extending through successive geological ages, but show us, on the contrary, that every age has had its own kinds, differing among themselves in the same way as those of the Gulf of Mexico differ now from those of the Indian Ocean and the Pacific.  The scales of the oldest known fishes in the Silurian beds have the same microscopic structure as those of their representative types today, and yet I have never seen a single fossil fish presenting the same specific characters in the successive geological epochs.  The teeth of the oldest Sharks show the same microscopic structure as those of the present time, and we do not lack opportunities for comparison, since the former are as common in the mountain-limestone of Ireland as are those of the living Sharks on any beach where our fishermen boil them for the sake of their oil, and yet the Sharks appear under different generic and specific forms in each geological age.

But without multiplying examples, which might be adduced ad infinitum, to show permanence of type combined with repeated changes of species, suffice it to say, that, while the general features in the framework of the organic world and the materials of which that framework is built, though quite as subject to the influence of physical external circumstances as any so-called specific-features, have remained perfectly intact from the beginning of Creation till now, so that not the smallest difference is to be discerned in these respects between the oldest representatives of the oldest types in the oldest Silurian rocks and their successors through all the geological ages up to the present day, the species have been different in each epoch.  It is surely a fair question to ask the advocates of the transmutation theory, whether they attribute to physical laws the discernment that would lead them to change the specific features, but to respect all those characters by which the higher structural combinations of the Animal Kingdom are preserved without alteration,—­in other words, to maintain the organic plan, while constantly diversifying the mode of expressing it.  If so, it would perhaps be as well to call them by another name, since they show all the comprehensive wisdom of an intelligent Creator.  Until they can tell us why certain features of animals and plants are permanent under conditions which, according to their view, have power to change certain other features no more perishable or transient in themselves, the supporters of the development theory will have failed to substantiate their peculiar scientific doctrine.