One hundred years ago, Sigmund Freud arrived in the United States on his first and only visit. As the George Washington pulled into New York Harbor, he supposedly remarked to Carl Jung, who accompanied him, "They don't realize that we are bringing them the plague." His more vociferous contemporary critics would probably agree.

Freud came to deliver five lectures over five days in September 1909 at Clark University. Its president, G. Stanley Hall, had invited a number of leading thinkers to celebrate the 20th anniversary of Clark. Clark? For our rank-obsessed society, that might seem surprising. Not Chicago or Princeton or Columbia but a small Massachusetts university with just 16 faculty members had invited one of the pivotal thinkers of the 20th century. Indeed, William James came over from Harvard to listen to the lectures. Perhaps we overlook the role of the smaller and less flashy schools in American cultural life. Twenty-four years later a small outfit on West 12th Street in Manhattan hired many more refugees from Nazism than more celebrated institutions. In its housing of exiled scholars, the New School far eclipsed grander universities.

Perhaps the balance of wealth in the early part of the century was not as skewed as it is nowadays; or at least Hall's invitation to Freud opens a small window into a neglected question of the economics of writing and lecturing. Hall first offered Freud an "honorarium" of $400 to cover expenses to lecture in July. Freud declined because he would lose too much income by canceling three weeks of private consultations. Hall upped the honorarium to $750, and the lectures were shifted to September, when Freud had no appointments.

An honorarium of $750 is roughly in the league of what might be paid a professor nowadays to fly across the country and give a lecture, if he or she is lucky. Of course a 1909 greenback is not a 2009 greenback. Various indexes exist to update past prices. Readjusted in current dollars, $750 in 1909 computes out to something between $18,000 and $36,000 in 2009—not a bad piece of change! Few writers or professors would turn down an offer nowadays to give some lectures if the invitation came with a $20,000 honorarium. The amount not only suggests the relative wealth of Clark—Hall had $10,000, or half a million in current dollars, to spend on the anniversary—but the generous remuneration for independent lectures in the early part of the 20th century.

Freud spoke off the cuff from notes to a good crowd. Yet contemporary observers of the Clark lectures did not mention what today would be extraordinary. Freud spoke in German with no translation provided. Today if Jürgen Habermas lectured in German at an American university, the audience could comfortably sit around a small table. But a century ago, a series of lectures in German neither diminished the audience nor elicited disapproval. In 1909 advanced study usually meant study in Germany. It was assumed the professoriate knew German. Today the opposite is true. That might not be a reason for dismay, if other languages have replaced German, but that has not happened. The din about globalization evades the reality of the decline of serious language study among American students. Globalization spells "English Spoken Here."

Freud suspected that American prudishness would curtail the reception of his ideas. I think, he wrote to Jung before they departed, that once the Americans "discover the sexual core of our psychological theories they will drop us." Later critics of Freud, especially feminist critics, forget to what extent he showed up as a militant sexual reformer. He wanted to be able to talk about sexual desire and liberalize sexual practices. He made no effort to mute that message. Freud's five lectures closed with a call to allow greater sexual freedom. He said civilization demands "excessive" sexual repression. "We ought not to aim so high that we completely neglect the original animality of our nature." He cautioned that it was not possible to "sublimate" all sexual impulses into cultural accomplishments.

To drive his point home, Freud closed with an analogy and recounted a folk tale about the foolish residents of Schilda.

They owned a strong and productive horse with one flaw, its need for expensive oats. The thrifty citizens decided to gradually cut down its ration until the horse grew accustomed to "complete abstinence." The plan of action went well until one day the townspeople woke up and found the horse had died. This perplexed them. Freud closed his last lecture and formal visit to the United States with the following sentence: "We are inclined to believe that the horse had died of starvation and that without a certain ration of oats, no work can indeed be expected from an animal."

In the first rows of the audience sat Emma Goldman, the anarchist and sexual reformer, with her lover Ben Reitman.

She was "deeply impressed" by Freud's "lucidity" and "the simplicity of his delivery." (She did not comment that he lectured in German.) She also attended the ceremony where Freud received an honorary degree. The other professors appeared "stiff and important in their university caps and gowns," but Freud looked "unassuming" in his ordinary attire.

She called him a "giant among pygmies."

If he needed it, a reference from Emma Goldman could burnish Freud's credentials as a sexual reformer. Yet an opening and incidental sentence to his five lectures may prove more prescient than his last: "I have discovered with satisfaction that the majority of my audience are not of the medical profession." The observation seems trivial, but much turned on it. With virtually no success in the United States, Freud fought what might be called the monopolization of psychoanalysis by medical doctors. He wanted nonmedical or lay people to practice psychoanalysis, if they were properly trained. This was no minor issue to Freud. He distrusted the medical profession. He feared that doctors would turn psychoanalysis into a subfield, a narrow therapy. I do not "consider it at all desirable for psychoanalysis to be swallowed up by medicine," he wrote, "and to find its last resting place in a textbook of psychiatry under the heading, 'Methods of Treatment.'"

In fact, that more or less happened. American doctors banished lay practition-ers and made psychoanalysis into a medical speciality. For decades psychoanalysis prospered as psychiatrists embraced it, but more recently the doctors have moved on. Psychoanalysis was too slow, too expensive, too uncertain, and too unscientific. Along with academic psychologists, psychiatrists adopted chemical, behavioral, and pharmaceutical approaches.

But Freud did not defend psychoanalysis on the basis of its therapeutic effectiveness; he had other, perhaps more imperial ambitions. ("Somewhere in my soul," he admitted, "I am a fanatical Jew.") He wanted psychoanalysis to contribute to literature and culture, even reform society. He invoked the possibility of "combating the neuroses of civilization." He wrote smaller and smaller books on bigger and bigger subjects, such as The Future of an Illusion (on religion) and Civilization and Its Discontents (on happiness and aggression).

This may be the "plague" that Freud brought to the New World: uninhibited thinking. To be sure, the molecular, genetic, or chemical perspective may be perfectly suitable for treating many ailments or behaviors. Yet the clamorous effort to rid the world of Freud is misguided. Psychology departments may relegate psychoanalysis to phrenology and other quackeries as they seek testable results, but Freud's thought lives on in the humanities—or wherever scholars and students contemplate the vagaries of desire, morality, and religion. In the name of reason, Freud challenged the veneer of reason. He dug to uncover the forces that make us not only loving but also odd, hateful, and violent. Even when he was wrong, a boldness infused his thinking. He remains a tonic for a cautious age. The epigram that Freud chose for The Interpretation of Dreams—a line from Virgil—has not lost its appeal: "If I cannot bend the higher powers, I shall stir up hell."

Russell Jacoby is a professor in residence in the history department at the University of California at Los Angeles. A columnist for The Chronicle Review, he is author, most recently, of Picture Imperfect: Utopian Thought for an Anti-Utopian Age (Columbia University Press, 2005).