In May 1840, Harriet gave birth to another son, Frederick William. Two years later, in 1842, her first short story collection was published by Harper under the name The Mayflower. In 1843, Harriet's brother George accidentally shot and killed himself while shooting at birds in the fruit trees in his backyard. To make matters worse, Lane Theological Seminary was on the verge of collapse, and Calvin was rarely getting paid. Harriet continued to write to support the family, and she was finding that she returned again and again to the topic of slavery, both in her essays and articles and in her short stories.
Her short story "Immediate Emancipation," which appeared in the January 1845 issue of New York Evangelist, found its inspiration in a horrific scene Harriet had witnessed a few months before. She had watched as a slave family was split apart by an auction on a Kentucky plantation. The father was sold to one plantation owner, the mother to another. The child, suddenly an orphan, was sobbing. Harriet was so distressed by the scene that she collected enough money–by digging into her family's meager savings and by borrowing the rest from friends–to buy the child and reunite her with her mother.
Around this time, a rift appeared in the Presbyterian Church regarding slavery. Lyman Beecher was in the middle of the controversy. The conservative Presbyterian faction was more tolerant of slavery, and even made excuses for its continued existence. They wanted Lyman Beecher out of the church because he was, in their view, too liberal on this question. Harriet, who had recently given birth to a daughter, Georgiana May, was greatly distressed by this turn of events. The Beechers' outspoken opposition to slavery was costing them friends, status, and jobs.
Harriet began teaching the children of her maid, an ex-slave named Eliza Buck. She was shocked to learn that all of them had been fathered by Eliza's former master. Eliza's stories of brutal beatings, of inhuman living conditions, and of the nightly visits to her cabin by the master were horrifying to Harriet. Her belief in moderate abolitionism wavered under her great rage.
In the summer of 1845, Harriet was struck with cholera. Her case was so bad that she was expected to die. Calvin held vigil at her bedside for weeks. She barely recovered, and was certain she'd be an invalid for the rest of her life. As the months wore on, however, she regained strength and began writing again. Three years later, she gave birth to a boy she named Samuel Charles. When Calvin Stowe fell ill the next year, Harriet assumed even more of the family's financial burden, and worked endlessly, churning out article after article and story after story. As always, she considered her writing a business rather than an act of art. Although Calvin recovered, her infant son Samuel died of cholera in 1849.
Calvin Stowe was offered a job at Bowdoin College in Maine. Although rooted in the Cincinnati community, Harriet was inclined to leave for the east again as many of the Beechers had, in the intervening years, moved back to New England. In July, while Calvin and Harriet were pondering the move, Harriet gave birth to another boy, named Charles. Although the 1840's and 1850's were a time in which great political, economic and social questions were hanging in the air, Harriet seemed to ignore all of them save one very specific issue: the abolition of slavery. Even tangential political developments go unmentioned in her many lengthy letters. There is little evidence, for example, that she was keeping abreast of developments like the Mexican War. However, the 1850 Compromise, which made it mandatory for Northerners to return escaped slaves to Southern slave owners had Harriet and the other Beechers up in arms. In reaction, they became active members of the Underground Railroad. During the mid-nineteenth century, harboring a runaway slave was a federal offense, and the Underground Railroad was a subversive organization.