300 Wiehr conditions of its existence. This aggregate of individual organ- isms which constitute the body of the animal are the milieu interieur dans lequel vivent les elements des tissus. It forms the immediate milieu of the different cells; to regard it as the inner milieu of the collective organism, the animal, is indeed a departure, but one which does not make for clearness. Finot's definition recommends itself by its brevity, clearness and inclusiveness. He states, milieu " includes the sum total of the conditions which accompany the conception and earthly existence of a being, and which end only with its death. " It is possible, and it may have been Finot's intention, to include Bernard's milieu interieur in his interpretation. But by doing so, one greatly obscures, if not entirely eliminates, the boundary between heredity and environment, for every trait or propensity inherited from the parents would at the moment of conception merely become an aspect of the milieu interieur. After discussing the meaning of the term, Koller gives a sketch of the history of the idea of milieu down to the nine- teenth century. He finds that mesologic thinking begins with the ancient Hebrew prophets, refers then to Hippocrates and Aristotle and the views which the ancients in general held in regard to the influence of environment, and gives a more detailed exposition of the theories of Ibn Khaldun, an Arabic statesman and sage of the second half of the fourteenth century. In Europe of the Middle Ages, the idea remained dormant, until the time of the Renaissance, which witnessed its resur- rection. The reason for this is obvious. The ancient thinkers were fearless and inquisitive, and umhampered by any pre- conceived ideas or a fixed goal. Their observations were scattered and unsystematic, their inclination for philosophical speculation and their impatient desire for a harmonious con- ception of the universe often led them astray, but some of their deductions based on experience are very clear sighted, though naturally expressed in rudimentary form. Almost two hundred years before Aristotle, Empedocles maintained that the pre- servation, proficiency and development of all organisms were due to the fitness which they ultimately attained. In the language of the present age this simply means survival of the fittest. With the advent of Christianity a barrier was created for thought and simultaneously a fixed goal was set for which it had to strive. Only the heretics dared to arrive at conclusions which were at variance with the dogma. The importance of the inner life, the life of the soul, as then understood, over- shadowed the concrete experiences of existence. One fundamental idea of those ages was that the universe
was governed by an absolutely free will, and that human beings
