On July 7, 1962, after dropping the first game of a doubleheader to the Mets at the Polo Grounds in New York, Stan Musial picked the Cardinals up with a solo shot in the eighth inning of the second game to lead the team to a 3-2 victory. The next day Musial picked up three home runs in his first three at bats as he tied a major league record with four consecutive home runs in the 15-1 pummeling of the Mets. Bill White, Fred Whitfield, and Bob Gibson all joined Stan with a homer apiece in that contest. Stan was the only Cardinal to hit a homer in four consecutive at bats until Albert Pujols joined him in 2006. At the age of 41, Musial is the oldest player to hit three and four home runs in consecutive at bats.
Here's the box score: http://www.baseball-reference.com/boxes/NYN/NYN196207072.shtml
Here's the box score for the three home run game: