palliation vs soothing

palliation

noun
  • The alleviation of a disease's symptoms without a cure; temporary relief. 

  • Extenuation; mitigation. 

soothing

noun
  • The act by which somebody is soothed. 

adj
  • Giving relief. 

  • Freeing from fear or anxiety. 

  • Tending to soothe. 

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