medulla vs myeline

medulla

noun
  • The medulla oblongata. 

  • The soft inner part of something, especially the pith of a fruit. 

  • The internal tissue of a plant. 

  • The inner substance of various organs and structures, especially the marrow of bones. 

myeline

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