hemoglobin vs plasma

hemoglobin

noun
  • The iron-containing substance in red blood cells that transports oxygen from the lungs to the rest of the body; it consists of a protein (globulin), and haem (a porphyrin ring with an atom of iron at its centre). 

plasma

noun
  • Blood plasma, free of suspended cells, used in transfusions. 

  • A clear component of blood or lymph containing fibrin. 

  • A state of matter consisting of partially ionized gas and electrons. 

  • A visual effect in which cycles of changing colours are warped in various ways to give the illusion of liquid organic movement. 

  • A variety of green quartz, used in ancient times for making engraved ornaments. 

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