_Partial Lives._ _Collective Life._—With the exception of the physiologist, no one, neither he who is ignorant nor he who is intellectual, nor even the doctor, troubles his head about the life or the death of the element, although this is the basis, the real foundation, of the activity manifested by the social body and by its different organs. The life of the individual, of the animal, depends on these elementary partial lives just as the existence of the State depends upon that of its citizens. To the physiologist, the organism is a federation of cellular elements unified by close association. Goethe compared them to a “multitude”; Kant to a “nation”; and others have likened them to a populous city the anatomical elements of which are the citizens, and which possesses an individuality of its own. So that the activity of the federated organism may be discussed in each of its parts, and then it is _elementary life_, or in its totality, and then it is _general life_. Paracelsus and Bordeu had a glimpse of this truth when they considered a life appropriate to each part (_vita propria_) and a collective life, the life of the whole (_vita communis_). In the same way we must distinguish the _elementary death_, which is the cessation of the vital phenomena in the isolated cell, from the _general death_, which is the disappearance of the phenomena which characterised the collectivity, the totality, the federation, the nation, the city, the whole in so far as it is a unit. These comparisons enable us to understand how general life depends on the partial lives of each anatomical citizen. If all die, the nation, the federation, the total being clearly ceases to exist. This city has an enormous population—there are thirty trillion cellules in the body of man; it is peopled with absolutely sedentary citizens, each of which has its fixed place, which it never leaves, and in which it lives and dies. It must possess a system of more or less perfect arrangements to secure the material life of each inhabitant. All have analogous requirements: they feed very much the same; they breathe in the same way; each in fact has its profession, industry, talents, and aptitudes by which it contributes to social life, and on which, in its turn, it depends. But the process of alimentation is the same for all. They must have water, nitrogenous materials and analogous ternaries; the same mineral substances, and the same vital gas, oxygen. It is no less necessary that the wastes and the egesta, very much alike in every respect, should be carried off and borne away in discharges arranged so as to free the whole system from the inconvenience, the unhealthiness, and the danger of these residues.