In the early 1920's, around 1922 or so, Sinclair Lewis met a man named Paul De Kruif who had worked for the Rockefeller Institute and who had published a series of articles in Century magazine attacking the practices of modern American medicine. Lewis, in his novel Arrowsmith takes the torch carried by De Kruif who had to leave the Rockefeller Institute because of his critique.
It was the early twenties, and America was living through an economic boom from the war, where everything was becoming more commercial—American businesses were booming. And, further, even practices like medicine were becoming "businesses." The consequences of medicine becoming a business is what Lewis criticizes, specifically the commercialism and competition that exist within the profession and which seem to contradict its nature. Instead of being a practice of altruism, discovery, and healing, medicine had become something institutions needed to sell. Lewis uses the Rouncefield Institute, the Public Health Department of Nautilus, and the McGurk institute as vehicles of satire in order to criticize the real institutions that existed in America at this time. In many ways the novel was educating the American public about the maladies of medicine in the early twentieth century.
Martin Arrowsmith is a laboratory man, not a physician. The juxtaposition of the laboratory man and the physician are present throughout and are epitomized in the characters of Gottlieb and Dean Silva, respectively. The physician is a public figure and, depending on where he practices, is often trusted and a minor celebrity. The doctor because he heals is therefore generally admired (when he is a good doctor). The scientist, however, is a solitary person, a lonely person. The scientist must work alone in the laboratory, and when he makes discoveries usually only a small sector of the world is aware of it. Sometimes the scientist goes unrecognized for years, as Gottlieb had gone. Further still, if we are to surmise that Gottlieb is to represent "the scientist," then we come to the conclusion that the scientist has a solitary, exhausted, and unhappy end. The plight of the scientist is therefore a difficult one.
And yet, Martin seems, to be able to accept the "failures" that exist in his profession, where he will always be an outsider and never a "success." In fact, he seems almost able to embrace the likelihood of "failure," and it is in the acceptance of the romanticized "plight of the scientist" that the book ends in an ironically optimistic fashion.
Throughout the novel Martin finds his peace, his happiness, and his adventurous thrills while he is alone in the laboratory. Solitude and retreat become his true companions, aside from Leora whom Martin knows so well that he can be alone even while with her. As soon as Martin becomes a social being, as soon as he accepts luxury and the idea of "success," he begins to stray from his path and eventually becomes unhappy without the solitude of his laboratory work.
Many of the characters we come to like, moreover, are lonely figures: Martin, Terry, and Gottlieb, for instance. Many of the characters we are meant to dislike are very social beings: Tubbs and Holabird, for instance. Moreover, this solitude and retreat is romanticized and even elevated in a Thoreau-like fashion by the time we reach the end. In the end, Martin moves to the woods with Terry Wickett, where they will create a laboratory all their own. There is a "salvation" in this "retreat," for Martin has finally accepted the power of independence. This retreat is what makes the novel optimistic; Martin is finally able to flee form the social and commercial department heads that hinder his true work.