Emil adolf von behring was not defeated by repeated failures. If he stops insisting when he encounters difficulties, there may not be serum therapy yet. Just like a well digger, if he persists, he may find a well water, but if he loses patience and finally gives up, he will only get lifelong regret.

This rejection is the next approval; This persistence is the beginning of the next achievement; Today's misfortune often indicates tomorrow's good luck, and failure may be the best beginning of success.