permeate vs transudation

permeate

noun
  • Liquid that has passed through a filtration system. 

  • A watery by-product of milk production. 

verb
  • To pass through the pores or interstices of; to penetrate and pass through without causing rupture or displacement; applied especially to fluids which pass through substances of loose texture 

  • To enter and spread through; to pervade. 

transudation

noun
  • the process of passing through a membrane, pore or interstice 

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