froth at the mouth vs spurge

froth at the mouth

verb
  • To spew saliva as froth. 

  • To rage, to vent one's anger. 

spurge

verb
  • To emit foam; to froth; said of the emission of yeast from beer during fermentation. 

noun
  • Any plant of the genus Euphorbia, a diverse genus of over 2,000 species. 

How often have the words froth at the mouth and spurge occurred in a corpus of books? (source: Google Ngram Viewer )