Worlds exist in which the vital movements, respiration, assimilation, the organic periods, day and night, the seasons and the years, are all of extreme length. Although the nervous system of the human inhabitants is highly developed, and thought has a prodigious activity, life there appears to be of an endless length. Those who die of old age have lived more than a thousand of these years, but they are so rare that the memory of a few only have been preserved in the historical records of this humanity. War between the nations has never been invented, because there is only one race, one people, one language. The natural constitutions of these organisms are remarkable. Diseases are almost unknown; there are no doctors. As a result of this great mental activity, the length of life becomes a perspective without end, and before long becomes a burden. Hence suicide is almost universal. This custom has been habitual from very ancient times. The few old men who from any special motive have not put an end to their lives, are looked upon as exceptional beings, originals, and more or less eccentric. Suicide is the general law. But, my dear friend, it is impossible for me to describe to you all the curiosities of the universe. Let it suffice that I have raised the veil sufficiently, to give you a glimpse of the incommensurable diversity that exists, in the animated productions of all the various systems disseminated through space. [Sidenote: Infinite diversity] While accompanying me in spirit in this interstellar voyage, you have passed several hours away from the Earth. It is well to isolate one's self thus at times amongst the celestial solitudes. The soul obtains a fuller possession of itself, and in its solitary reflections it penetrates profoundly into the universal reality. Terrestrial humanity, you understand, is, as regards moral as well as physical life, the result virtually of the forces of the Earth. Human strength, figure, weight, all depend on these forces. The organic functions are determined by the planet. If life is divided with you between work and rest, between activity and sleep, it is because of the rotation of the globe, and day and night. In the luminous globes, and those lighted by many Suns alternately, they do not sleep. If you need to eat and drink, it is in consequence of the insufficiency of the atmosphere. The bodies of the beings who do not eat are not constructed like yours, since they have no need of a stomach and intestines. The terrestrial eye enables you to see the universe in a certain way, the Saturnian eye sees in a different manner. [Sidenote: Other senses than those of the Earth.]