We thus find ourselves confronted with a problem of vital importance to our well-being as a nation. We are called upon to explain why it is that, notwithstanding the exceptional advantages we possess, in an ever-increasing command over the more recondite powers of nature, an ever-increasing use of labour-saving machinery, a body of labourers whose industry and skill are proverbial, and far more complete and perfect communication with the whole world than was possessed by any previous generation—notwithstanding all these favourable conditions, which would seem to render prosperity certain, we yet find trade crippled and labour paralysed, goods of all kinds selling at unremunerative prices, yet the masses too poor to buy, and universal complaints of diminished profits and restricted markets. So long as these questions are not fully and completely answered, so long as a remedy is not found for the widespread and persistent evil which afflicts the mass of our people, our whole system of social economy, even our civilisation itself, must be accounted to be failures. It will undoubtedly be admitted that a system of society under which willing hands cannot find profitable work, and countless shops and warehouses overflowing with every necessary, comfort, and luxury, mock the longing eyes of insufficiently-clad and half-starved millions, is neither a sound nor a safe one.
We may therefore expect to find that the problem of trade-depression is fundamentally the same as that of the persistence of widespread poverty and pauperism notwithstanding our rapid and continuous growth in wealth; and if this be so, its solution will assuredly furnish us with some important principles to direct the course of future legislation. The main points of a sound political programme may be one of the important results of a successful investigation into the causes which have brought about the present depression of trade.
The term "species" was thus defined by the celebrated botanist De Candolle: "A species is a collection of all the individuals which resemble each other more than they resemble anything else, which can by mutual fecundation produce fertile individuals, and which reproduce themselves by generation, in such a manner that we may from analogy suppose them all to have sprung from one single individual." And the zoologist Swainson gives a somewhat similar definition: "A species, in the usual acceptation of the term, is an animal which, in a state of nature, is distinguished by certain peculiarities of form, size, colour, or other circumstances, from another animal. It propagates, 'after its kind,' individuals perfectly resembling the parent; its peculiarities, therefore, are permanent."
To illustrate these definitions we will take two common English birds, the rook (Corvus frugilegus) and the crow (Corvus corone). These are distinct species, because, in the first place, they always differ from each other in certain slight peculiarities of structure, form, and habits, and, in the second place, because rooks always produce rooks, and crows produce crows, and they do not interbreed. It was therefore concluded that all the rooks in the world had descended from a single pair of rooks, and the crows in like manner from a single pair of crows, while it was considered impossible that crows could have descended from rooks or vice versâ. The "origin" of the first pair of each kind was a mystery. Similar remarks may be applied to our two common plants, the sweet violet (Viola odorata) and the dog violet (Viola canina). These also produce their like and never produce each other or intermingle, and they were therefore each supposed to have sprung from a single individual whose "origin" was unknown. But besides the crow and the rook there are about thirty other kinds of birds in various parts of the world, all so much like our species that they receive the common name of crows; and some of them differ less from each other than does our crow from our rook. These are all species of the genus Corvus, and were therefore believed to have been always as distinct as they are now, neither more nor less, and to have each descended from one pair of ancestral crows of the same identical species, which themselves had an unknown "origin." Of violets there are more than a hundred different kinds in various parts of the world, all differing very slightly from each other and forming distinct species of the genus Viola. But, as these also each produce their like and do not intermingle, it was believed that every one of them had always been as distinct from all the others as it is now, that all the individuals of each kind had descended from one ancestor, but that the "origin" of these hundred slightly differing ancestors was unknown. In the words of Sir John Herschel, quoted by Mr. Darwin, the origin of such species was "the mystery of mysteries."