Student or Learner
"...,but the boy must take himself by the collar and make himself..." What does "take oneself by the collar" mean? Is it an idiom?
A Word A Day:
Yes; it is an idiom, albeit an old-fashioned, one in BrE. To "take someone by the collar" is to stop them doing something bad or inadequate, and start them off doing something better. In other words, to make someone change his or her ways. This boy must do that for himself. It's also expressed more forcefully as taking someone "by the scruff of the neck".
I'm not a teacher of English, but I have spoken it for (almost) all of my life....