1. What’s past is prologue1
Walter H. Merrill, MD 
The Annals of Thoracic Surgery 
Volume 68, Issue 6, Pages (December 1999)
DOI: /S (99)

2. Fig 1 Doctor Alfred Blalock about 1950. ©Yousuf Karsh.
The Annals of Thoracic Surgery  , DOI: ( /S (99) )

3. Fig 2
Alfred Blalock’s letter to W. S. Halsted, MD, dated December 1, 1921.
The Annals of Thoracic Surgery  , DOI: ( /S (99) )

4. Fig 3 The Vanderbilt University Hospital, 1925.
The Annals of Thoracic Surgery  , DOI: ( /S (99) )

5. Fig 4
Subsequent locations of residents who completed their training under Blalock and held positions of Department Chair or Division Chief.
The Annals of Thoracic Surgery  , DOI: ( /S (99) )