congeal vs ossify

congeal

verb
  • To become congealed, solidify. 

  • To change from a liquid to solid state, perhaps due to cold; called to freeze in nontechnical usage. 

  • To coagulate, make curdled or semi-solid such as gel or jelly. 

  • To make rigid or immobile. 

ossify

verb
  • To grow (or cause to grow) formulaic and permanent. 

  • To transform (or cause to transform) from a softer animal substance into bone; particularly the processes of growth in humans and animals. 

  • To become (or cause to become) inflexible and rigid in habits or opinions. 

  • To calcify. 

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