of Ireland in which there occurs a small plant of the cord-rush family, (_Eriocaulon septangulare_,) which, though common in America, is nowhere to be found on the European Continent. It is the only British plant which belongs to no other part of Europe. How was it transported across the Atlantic? Entangled, mayhap, in the form of a single seed,—for its seeds are exceedingly light and small,—in the plumage of some water-fowl, free of both sea and lake, it had been carried in the germ from the weed-skirted edge of some American swamp or mere, to some mossy lochan of Connaught or of Skye; and one such seed transported by one such accident, unique in its occurrence in thousands of years, would be quite sufficient to puzzle all the botanists forever after. I have seen the seed of one of our Scotch grasses, that had been originally caught in the matted fleece of a sheep reared among the hills of Sutherland, and then wrought into a coarse, ill-dressed woollen cloth, carried about for months in a piece of underclothing. It might have gone over half the globe in that time, and, when cast away with the worn vestment, might have originated a new circle for its species in South America or New Holland. There are seeds specially contrived by the Great Designer to be carried far from their original habitats in the coats of animals,—a mode which admits of transport to much greater distances than the mode, also extensively operative, of consigning them for conveyance to their stomachs; and when we see the work in its effects, we are puzzled by the want of a record of an emigratory process, of which, in the circumstances, no record could possibly exist. Unable to make out a case for the “shaking of the bag,” we bethink us, in the emergency, of repetition of creation. But in circles separated by _time_, not space,—by _time_, across whose dim gulfs no voyager sails, and no bird flies, and over which there are no means of transport from the point where a race once fails, to any other point in the future,—we find no repetition of species. If the production of perfect duplicates or triplicates in independent centres were a law of nature, our works of physical science could scarce fail to tell us of identical species found occurring in widely-separated systems,—Scotch firs and larches, for instance, among the lignites of the Lias, or _Cyprina islandica_ and _Ostrea edulis_ among the shells of the Mountain Limestone. But never yet has the geologist found in his systems or formations any such evidence as facts such as these might be legitimately held to furnish, of the independent _de novo_ production of individual members of any single species. On the contrary, the evidence lies so entirely the other way, that he reasons on the existence of a family relation obtaining between all the members of each species, as one of his best established principles. If members of the same species may exist through _de novo_ production, without hereditary relationship,