In order to deal with this problem, and to demonstrate the general nature of a movement having such diverse components, we must, continues Professor Draper, select, from a family or a nation, or a family of many nations, such members or classes or states as most closely represent respectively its type or have advanced most completely in their career. In a state the leading or intellectual class is always the true representative. It has passed gradually through the lower stages, and has made the greatest advance. We are next called to notice that individual life is maintained only by the production and destruction of organic particles, death being necessarily the condition of life; and that a similar process occurs in the existence of a nation, in which the individual represents the organic molecule, whose production, continuance, and death in the person, answers to the production, continuance, and death of a person in the state. In the same manner that individuals change through the action of physical agencies and submit to impressions, so likewise do aggregates of men constituting nations. 'A national type pursues its way physically and intellectually through changes and developments answering to those of the individual, and being represented by infancy, childhood, youth, manhood, old age, and death, respectively.' This orderly process may, however, be disturbed by emigration, by blood admixture, or by other exterior or interior occurrences, which would involve a corresponding change in the national characteristics and duration; perhaps result in the rapid and total disappearance of the community. For--and this brings us to the last point of analogy which Professor Draper gives between individual and national life--nations, like individuals, die. Empires are only sandhills in the hourglass of Time; they crumble spontaneously away by the process of their own growth. 'A nation, like a man, hides from itself the contemplation of its final day. It occupies itself with expedients for prolonging its present state. It frames laws and constitutions under the delusion that they will last, forgetting that the condition of life is change. Very able modern statesmen consider it to be the grand object of their art to keep things as they are, or rather as they were. But the human race is not at rest; and bands with which, for a moment, it may be restrained, break all the more violently the longer they hold. No man can stop the march of destiny. * * * The origin, existence, and death of nations depend thus on physical influences, which are themselves the result of immutable laws. Nations are only transitional forms of humanity. They must undergo obliteration as do the transitional forms offered by the animal series. There is no more an immortality for an embryo in any one of the manifold forms passed through in its progress of development.