Summary

The New International Encyclopædia…

These philosophers were wont to be so absorbed in their speculations that they neither spoke, nor attended to what was said by others, until gently reminded by servants, who were supplied with blown bladders fastened like flails to the end of a sharp stick. With the bladders it was the duty of the servants to strike gently the mouths or ears of their masters in order to arouse them from their abstracted state of mind to answer questions.
Source: Wikisource

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