Many people in the 1940s and 1950s used drugs such as benzedrine, to help them stay alert. Jazz music was also popular, and some jazz musicians and listeners smoked marijuana. Kerouac was influenced by both drugs, and they changed the way he wrote. He began to write what he called " prose", jotting down words in much the same way a musician a solo in a song. (Kerouac played no musical instruments, but could well, and had many of the same instincts as a musician.) His new writing style was strange to many people, and even seen as bad by some older authors and critics. It was six years before Kerouac published his second novel.