Further, it must not only constantly receive stimulus from without, but
must also give out something from within, and the healthy life of the
organism will depend on these two fold activities of inflow and
outflow. When there is any interference with these activities, then
morbid symptoms appear, which ultimately must end in disaster and death.
This is equally true of the intellectual life of a Nation. When through
narrow conceit a Nation regards itself self-sufficient and cuts itself
from the stimulus of the outside world, then intellectual decay must
inevitably follow.