The Nazis' extermination programme was carried out in the name of eugenics - but they were by no means the only advocates of racial purification. In this extract from his extraordinary new book, Edwin Black describes how Adolf Hitler's race hatred was underpinned by the work of American eugenicists

At 4am on November 12 1915, a woman named Anna Bollinger gave birth at the German-American Hospital in Chicago. The baby was somewhat deformed and suffered from extreme intestinal and rectal abnormalities, as well as other complications. The delivering physicians awakened Dr Harry Haiselden, the hospital's chief of staff. Haiselden came in at once. He consulted with colleagues. There was great disagreement over whether the child could be saved. But Haiselden decided the baby was too afflicted and fundamentally not worth saving. It would be killed. The method: denial of treatment.

Catherine Walsh, probably a friend of Bollinger's, heard the news and sped to the hospital to help. She found the baby, who had been named Allan, alone in a bare room. Walsh pleaded with Haiselden not to kill the baby by withholding treatment. "It was not a monster - that child," Walsh later told an inquest. "It was a beautiful baby. I saw no deformities." Walsh had patted the infant lightly. Allan's eyes were open, and he waved his tiny fists at her. Begging the doctor once more, Walsh tried an appeal to his humanity. "If the poor little darling has one chance in a thousand," she pleaded, "won't you operate to save it?"

Haiselden laughed at Walsh, retorting, "I'm afraid it might get well." He was a skilled and experienced surgeon, trained by the best doctors in Chicago. He was also an ardent eugenicist. Allan Bollinger duly died. An inquest was convened a few days later. Haiselden defiantly declared, "I should have been guilty of a graver crime if I had saved this child's life. My crime would have been keeping in existence one of nature's cruellest blunders." A juror shot back, "What do you mean by that?" Haiselden responded, "Exactly that. I do not think this child would have grown up to be a mental defective. I know it."

After tempestuous proceedings, the inquest ruled: "We believe that a prompt operation would have prolonged and perhaps saved the life of the child. We find no evidence from the physical defects that the child would have become mentally or morally defective." But they also decided that Haiselden was within his professional rights to decline treatment. No law compelled him to operate on the child. He was released unpunished, and efforts by the Illinois attorney general to indict him for murder were blocked by the local prosecutor. The doctor considered his legal vindication a powerful victory for eugenics. "Eugenics? Of course it's eugenics," he told one reporter.

Haiselden became an overnight celebrity, known for his many newspaper articles, his speaking tours and outrageous diatribes. In 1917, Hollywood came calling. The film was called The Black Stork. Written by Jack Lait, a reporter on the Chicago American, it was produced in Hollywood and given a massive national distribution and promotion campaign. Haiselden played himself in a fictionalised account of a eugenically mismatched couple whom he advises not to have children because they are likely to be defective. Eventually, the woman does give birth to a defective child, whom she then allows to die. The dead child levitates into the waiting arms of Jesus Christ. It was unbridled cinematic propaganda for the eugenics movement; the film played at movie theatres around the country for more than a decade.

National publicity advertised it as a "eugenic love story". One advertisement quoted Swiss eugenicist Auguste Forel's warning: "The law of heredity winds like a red thread through the family history of every criminal, of every epileptic, eccentric and insane person. Shall we sit still ... without applying the remedy?" In 1917, a display advertisement for The Black Stork read: "Kill Defectives, Save the Nation and See 'The Black Stork'." Various methods of eugenic euthanasia - including gassing the unwanted in lethal chambers - were a part of everyday American parlance and ethical debate some two decades before Nevada approved the first such chamber for criminal executions in 1921.

As America's eugenics movement gathered pace, it inspired a host of imitators. In France, Belgium, Sweden, England and elsewhere in Europe, cliques of eugenicists did their best to introduce eugenic principles into national life; they could always point to recent precedents established in the United States.

Germany was no exception. From the turn of the century, German eugenicists formed academic and personal relationships with the American eugenics establishment, in particular with Charles Davenport, the pioneering founder of the Eugenics Record Office on Long Island, New York, which was backed by the Harriman railway fortune. A number of other charitable American bodies generously funded German race biology with hundreds of thousands of dollars, even after the depression had taken hold.

Germany had certainly developed its own body of eugenic knowledge and library of publications. Yet German readers still closely followed American eugenic accomplishments as the model: biological courts, forced sterilisation, detention for the socially inadequate, debates on euthanasia. As America's elite were describing the socially worthless and the ancestrally unfit as "bacteria," "vermin," "mongrels" and "subhuman", a superior race of Nordics was increasingly seen as the answer to the globe's eugenic problems. US laws, eugenic investigations and ideology became blueprints for Germany's rising tide of race biologists and race-based hatemongers.

One such agitator was a disgruntled corporal in the German army. In 1924, he was serving time in prison for mob action. While there, he spent his time poring over eugenic textbooks, which extensively quoted Davenport, Popenoe and other American ethnological stalwarts. And he closely followed the writings of Leon Whitney, president of the American Eugenics Society, and Madison Grant, who extolled the Nordic race and bemoaned its "corruption" by Jews, Negroes, Slavs and others who did not possess blond hair and blue eyes. The young German corporal even wrote one of them fan mail.

In The Passing of the Great Race, Grant wrote: "Mistaken regard for what are believed to be divine laws and a sentimental belief in the sanctity of human life tend to prevent both the elimination of defective infants and the sterilisation of such adults as are themselves of no value to the community. The laws of nature require the obliteration of the unfit and human life is valuable only when it is of use to the community or race."

One day in the early 1930s, Whitney visited Grant to show off a letter he had just received from Germany, written by the corporal, now out of prison and rising in the German political scene. Grant could only smile. He pulled out his own letter. It was from the same German, thanking Grant for writing The Passing of the Great Race. The fan letter called Grant's book "his Bible". The man who sent those letters was Adolf Hitler.

Hitler displayed his knowledge of American eugenics in much of his writing and conversation. In Mein Kampf, for example, he declared: "The demand that defective people be prevented from propagating equally defective offspring is a demand of clearest reason and, if systematically executed, represents the most humane act of mankind. It will spare millions of unfortunates undeserved sufferings, and consequently will lead to a rising improvement of health as a whole."

Mein Kampf also displayed a familiarity with the recently passed US National Origins Act, which called for eugenic quotas. "There is today one state in which at least weak beginnings toward a better conception [of immigration] are noticeable. Of course, it is not our model German Republic, but [the US], in which an effort is made to consult reason at least partially. By refusing immigrants on principle to elements in poor health, by simply excluding certain races from naturalisation, it professes in slow beginnings a view that is peculiar to the People's State."

Hitler proudly told his comrades how closely he followed American eugenic legislation. "Now that we know the laws of heredity," he told a fellow Nazi, "it is possible to a large extent to prevent unhealthy and severely handicapped beings from coming into the world. I have studied with interest the laws of several American states concerning prevention of reproduction by people whose progeny would, in all probability, be of no value or be injurious to the racial stock."

Nor did Hitler fail to grasp the eugenic potential of gas and the lethal chamber, a topic that was already being discussed in German eugenic circles before Mein Kampf was published. Hitler, who had himself been hospitalised for battlefield gas injuries, wrote: "If at the beginning of the war and during the war 12,000 or 15,000 of these Hebrew corrupters of the people had been held under poison gas, as happened to hundreds of thousands of our best German workers in the field, the sacrifices of millions at the front would not have been in vain. On the contrary: 12,000 scoundrels eliminated in time might have saved the lives of a million real Germans, valuable for the future."

On January 30 1933, Hitler seized power. During the 12-year Reich, he never varied from the eugenic doctrines of identification, segregation, sterilisation, euthanasia, eugenic courts and eventually mass termination in lethal chambers. During the Reich's first 10 years, eugenicists across America welcomed Hitler's plans as the logical fulfilment of their own decades of research and effort. Indeed, they were envious as Hitler rapidly began sterilising hundreds of thousands and systematically eliminating non-Aryans from German society. This included the Jews. Ten years after Virginia passed its 1924 sterilisation act, Joseph Dejarnette, superintendent of Virginia's Western State Hospital, complained in the Richmond Times-Dispatch: "The Germans are beating us at our own game."

Most of all, American raceologists were proud to have inspired the strictly eugenic state the Nazis were constructing. In those early years of the Third Reich, Hitler and his race hygienists carefully crafted eugenic legislation modelled on laws already introduced across America and upheld by the supreme court. Nazi doctors, and even Hitler himself, regularly communicated with American eugenicists from New York to California, ensuring that Germany would scrupulously follow the path blazed by the US. American eugenicists were eager to assist.

This was particularly true of California's eugenicists, who led the nation in sterilisation and provided the most scientific support for Hitler's regime. In 1934, as Germany's sterilisations were accelerating beyond 5,000 per month, the California eugenic leader and immigration activist CM Goethe was ebullient in congratulating ES Gosney of the San Diego-based Human Betterment Foundation for his impact on Hitler's work. Upon his return in 1934 from a eugenic fact-finding mission in Germany, Goethe wrote Gosney a letter of praise. The foundation was so proud of Goethe's letter that they reprinted it in their 1935 annual report.

"You will be interested to know," Goethe's letter proclaimed, "that your work has played a powerful part in shaping the opinions of the intellectuals behind Hitler in this epoch-making program. Everywhere I sensed that their opinions have been tremendously stimulated by American thought, and particularly by the work of the Human Betterment Foundation.

"I want you, my dear friend, to carry this thought with you for the rest of your life, that you have really jolted into action a great government of 60 million people."



· Extracted from War Against the Weak: Eugenics and America's Campaign to Create a Master Race, by Edwin Black, published by Turnaround, price £17.99. To order a copy for £15.99 plus p&p, call the Guardian book service on 0870 066 7979. Edwin Black is also the author of the New York Times bestseller, IBM and the Holocaust.