vent one's gall vs vent one's spleen

vent one's gall

verb
  • To openly express anger or frustration. 

vent one's spleen

verb
  • To openly express pent-up anger, often on an unrelated matter or person. 

How often have the words vent one's gall and vent one's spleen occurred in a corpus of books? (source: Google Ngram Viewer )