The 50 years that have passed since Secretariat's Herculean victory in the Belmont Stakes have taken a toll on the number of the 67,605 souls who came to witness history and saw a day sanctified by the racing gods. But then, unlike Secretariat, we are mere mortals. I am one of the dwindling number of those who were present on that sweltering day in June 1973. The memory of that magnificent day remains, intensely vibrant and charged with emotion, but it is now more a mosaic than a painting, with...