94 THE AMERICAN JOURNAL OF SOCIOLOGY
liquid environment; we know that the human body contains larger portion of liquid than solid material ; it is about 65 pei cent, water; the later is to the solid substance as 1.54: I. This environment accompanies each of us, in the same way that the land and the seas accompany humanity. We, indeed, complete our ancient maritime environment by the indispensable saline elements in our food, which enter into our constitution.
This static correlation between humanity and the geograph- ical structure seems to have been seen by Plato. When speaking of Greek civilization, more maritime than all others because of its shores and islands, he said: "We are seated on the shore like the frogs around a swamp;" and also by Strabo who, observing this same static relation between the geographical condition oi Greece and its civilization, said that the Greeks are "Amphib- ians." What for these ancient thinkers was, doubtless, only a figure is, indeed, a reality.
The natural islets emerging from the waves, the artificial islets created later in the midst of lakes, the banks of rivers, later those of the large rivers and their deltas, then the shores of the inland seas, and finally those of the large oceans, were the suc- cessive steps of civilizations in correlation with the geographical structure. Each of these natural limits was transformed, suc- cessively, into means of more extended communication up to the intercontinental structure, at the same time geographical and social, which has been increasingly maintained in the last four centuries, transforming the structure and function of boundaries of societies, and so necessarily their philosophy.
The frontier, the external limit of attack and defense, has been transformed into an internal organization for protection of the group and development of the interior; in the degree that the external barriers are broken down by the intersocial rela- tions, this protective membrane, so to speak, disappears and is transformed into intersocial organs; the envelope becomes more and more distant from the internal co-ordinated centers. The function of protection is not suppressed, but simply modified. The function persists and is constant ; its forms vary.
