pus vs secretion

pus

noun
  • A whitish-yellow or yellow substance composed primarily of dead white blood cells and dead pyogenic bacteria; normally found in regions of bacterial infection. 

verb
  • To emit pus. 

secretion

noun
  • any substance that is secreted by an organism 

  • the act of secreting a substance, especially from a gland 

  • the act of hiding something 

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