Ah! how fervently did Marc devote himself to that sowing and cultivation of truth! He strove to plan things in such wise that truth might impose itself on his pupils by its own power, nourish their expanding minds, and become both their flesh and their brains. And what truth it was! It so happens that every error claims to be truth. Does not even the Roman Catholic Church, though based on absurd dogmas, pretend that it is the sole truth? Thus Marc began by teaching that there is no truth outside the pale of reason, logic, and particularly experiment. When the son of a peasant or a workman is told by his schoolmaster that the world is round and revolves in space, he accepts the statement upon trust just as he accepts the statements made to him by the priest on matters of religion at the Catechism class. In order that he may appreciate the difference, experiment must show him the scientific certainty of the former statement. All so-called revealed truth is falsehood; experimental truth alone is accurate--one, entire, eternal. Marc therefore at the outset found it necessary to rebut the Catholic catechism by the scientific catechism. He took the world and mankind as they were explained by science, and set them forth in their living reality and their march towards a continual and ever more and more perfect future. There was no possibility of real amelioration, liberation, and happiness otherwise than by truth--that is, by knowledge of the conditions in which mankind exists and progresses. All the craving for knowledge as a means for rapid attainment to health and peace bore within itself its method of free expansion, science ceasing to be a dead letter, and becoming a source of life, an excitant of temperament and character. Marc, as far as possible, left books upon one side, in order to compel his pupils to judge things for themselves. They only knew things well when they had seen or touched them. He never asked them to believe in a phenomenon until he had proved its reality by experiment. The whole domain of unproven facts was set aside, in reserve, for future investigation. But he demonstrated that with the help of the acquired truths mankind might already rear for itself a large and splendid home of security and brotherliness. To see things for oneself, to convince oneself of what one ought to believe, to develop one's reasoning powers and one's individuality in accordance with the reasons of existence and action, such were the principles which governed Marc's teaching method, the only one by which true men might be created.