he traditional professions open to college graduates—law, the church, business, medicine—failed to interest Thoreau,:25 so in 1835 he took a leave of absence from Harvard, during which he taught school in Canton, Massachusetts. After he graduated in 1837, he joined the faculty of the Concord public school, but resigned after a few weeks rather than administer corporal punishment.:25 He and his brother John then opened a grammar school in Concord in 1838 called Concord Academy.:25 They introduced several progressive concepts, including nature walks and visits to local shops and businesses. The school ended when John became fatally ill from tetanus in 1842 after cutting himself while shaving. He died in his brother Henry's arms.
Upon graduation Thoreau returned home to Concord, where he met Ralph Waldo Emerson through a mutual friend. Emerson took a paternal and at times patronizing interest in Thoreau, advising the young man and introducing him to a circle of local writers and thinkers, including Ellery Channing, Margaret Fuller, Bronson Alcott, Nathaniel Hawthorne and his son Julian Hawthorne, who was a boy at the time.
Emerson urged Thoreau to contribute essays and poems to a quarterly periodical, The Dial, and Emerson lobbied editor Margaret Fuller to publish those writings. Thoreau's first essay published there was Aulus Persius Flaccus, an essay on the playwright of the same name, published in The Dial in July 1840. It consisted of revised passages from his journal, which he had begun keeping at Emerson's suggestion. The first journal entry on October 22, 1837, reads, "'What are you doing now?' he asked. 'Do you keep a journal?' So I make my first entry to-day."