With the affairs of active human beings it is different. Here knowledge of truth alone does not suffice; on the contrary this knowledge must continually be renewed by ceaseless effort, if it is not to be lost. It resembles a statue of marble which stan ds in the desert and is continuously threatened with burial by the shifting sands. The hands of science must ever be at work in order that the marble column continue everlastingly to shine in the sun. To those serving hands mine also belong