maturate vs milden

maturate

verb
  • To bring to ripeness or maturity; to ripen. 

  • To undergo perfect suppuration. 

  • To promote the perfect suppuration of (an abscess). 

milden

verb
  • To make or become mild or milder. 

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