Early in the short, the narrator states, "Joe and Alice have been feeling the rubber shortage ever since the game started." Rubber bridge is the card game the couples are playing. Additionally, the sentence also refers to the war-time shortage and rationing of rubber.
This short can be found in "The Bette Davis Collection Vo. 2" on the same disc as The Man Who Came to Dinner (1941).
The book Joe is trying to read is the 1941 novel "The Keys of the Kingdom" by A.J. Cronin. It would be made into a feature film of the same title in 1944 starring Gregory Peck and Vincent Price.
The couples are playing bridge.