In the dedication of The Harvester (1911) Porter wrote, "This portion of the life of a man of to-day is offered in the hope that in cleanliness, poetic temperament, and mental force, a likeness will be seen to Henry David Thoreau." Thus she identified the novel's primary social concerns: purity of life and appreciation of nature. David Langston's character is the product of his mother's moral teachings and his life in the woods; so his message to the medical convention concerns both his new medicine and the role of immorality in causing disease.

Because it helps to develop morality, nature should be cherished. Although David will destroy a plant to save a human life, he attempts to preserve endangered species, and he harvests wild plants sparingly. He is essentially a conservationist; but, more than Thoreau, he resembles Porter's friend, Theodore Roosevelt.

A major theme of The Harvester...