英语寓言故事-The Serpent and the File

A Serpent in the course of its wanderings came into an
armourer's shop.  As he glided over the floor he felt his skin
pricked by a file lying there.  In a rage he turned round upon it
and tried to dart his fangs into it; but he could do no harm to
heavy iron and had soon to give over his wrath.


It is useless attacking the insensible.