[2] After several years in private practice, Barrus took a job at the Middletown State Homeopathic Hospital for the Insane in 1893.

[5] Sources describe Barrus' and John Burroughs' relationship in a variety of ways, ranging from "devoted follower",[6] "friend, secretary, biographer, and almost constant traveling companion",[7] to "the great love of his life".

[5] When Ursula North Burroughs died in 1917 Barrus moved into his home Riverby in Ulster County, New York.

[8] During his lifetime, and after his death, Barrus wrote brochures, pamphlets, and books about Burroughs.

An early work was a brochure entitled "The Retreat of a Poet Naturalist" published in 1905.