indurate vs make insensitive

indurate

verb
  • To inure; to strengthen; to make hardy or robust. 

  • To harden or to grow hard. 

  • To make callous or unfeeling. 

adj
  • Hardened, obstinate, unfeeling, callous. 

make insensitive

How often have the words indurate and make insensitive occurred in a corpus of books? (source: Google Ngram Viewer )