The inefficient are weeded out and flung downward.

Various things constitute inefficiency.

The engineer who is irregular or irresponsible will sink down until he finds his place, say as a casual labourer, an occupation irregular in its very nature and in which there is little or no responsibility.

Those who are slow and clumsy, who suffer from weakness of body or mind, or who lack nervous, mental, and physical stamina, must sink down, sometimes rapidly, sometimes step by step, to the bottom.

Accident, by disabling an efficient worker, will make him inefficient, and down he must go.