differentialize vs secern

differentialize

verb
  • Synonym of differentiate 

secern

verb
  • To separate (something from other things) in the mind; to discriminate, to distinguish. 

  • Of a person or thing: to become separated from others. 

  • To secrete a substance. 

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