In pursuit of platelets--the third blood element.
D001792:Blood Platelets / Q000502:physiology*; D005060:Europe; D006405:Hematology / Q000266:history; D049670:History, 17th Century; D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D049690:History, Ancient; D006801:Humans