aphaeresis vs apheresis

aphaeresis

apheresis

noun
  • Elision, suppression, or complete loss of a letter or sound (syllable) from the beginning of a word, such as the development of special from especial; procope. 

  • The removal of blood from a patient, and the removal of certain components (such as platelets) from that blood, followed by the transfusion of the filtered blood back to the donor (patient). 

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