While there were many sensational stories in the "World", they were by no means the only pieces, or even the dominant ones. Pulitzer believed that newspapers were public institutions with a duty to improve society, and he put the "World" in the service of social reform. During a heat wave in 1883, "World" reporters went into the Manhattan's tenements, writing stories about the appalling living conditions of immigrants and the toll the heat took on the children. Stories headlined "How Babies Are Baked" and "Lines of Little Hearses" spurred reform and drove up circulation.