Martin Flack

{{Short description|English doctor and physiologist}}

{{Use dmy dates|date=April 2022}}

File:Portrait of Martin William Flack Wellcome L0011820.jpgMartin William Flack {{post-nominals|country=GBR|CBE}} (20 March 1882 – 16 August 1931) was a British physiologist who co-discovered the sinoatrial node with Sir Arthur Keith in 1907.{{cite journal|last1=Silverman|first1=M. E|last2=Hollman|first2=A.|title=Discovery of the sinus node by Keith and Flack: on the centennial of their 1907 publication|journal=Heart|date=1 October 2007|volume=93|issue=10|pages=1184–1187|doi=10.1136/hrt.2006.105049|pmc=2000948|pmid=17890694}}

Flack later became demonstrator of physiology at the London Hospital and later a lecturer. He served on the Medical Research Council and became the director of medical research for the Royal Air Force. He was appointed a Commander of the Order of the British Empire in the 1919 New Year Honours.{{London Gazette |issue=31098 |supp=y |page=92|date= 1 January 1919}}