If the peoples of today are a confused mix of what was once a series of pure races, it might still be possible to identify perfect specimens of the original groups. That unproven idea led human biology round in circles for centuries in a futile attempt to find divisions into which people could be classified. Its early days were spent in a useless search for homelands and migration routes. Harvard University was at the centre of the search for the archetype. Two suitably discreet nude statues once stood in the Pea-body Museum of Anthropology. They were based on measurements made in the 1930s on dozens of male and female students. Average these out, the argument went, and one would produce an image of the ideal Harvard undergraduate — the highest form of human being. A remnant of this philosophy survives in the Miss World Contest whose judges try, and fail, to find an objective definition of the perfect woman.

Racial types were usually identified from skulls. The word 'Caucasian' reflects a claim that the skull which best represented white-skinned people came from the Caucasus Mountains so that — perhaps — the white race had spread from those remote fastnesses. Years were wasted in measuring skulls rather than thinking about what might make them different. The most popular yardstick was the cephalic index, the ratio of the length and breadth of the head. Tens of thousands of crania from different parts of the world were measured in an attempt to sort out their ancestral stocks.

The work was futile. There is no evidence at all that there are, or ever have been, populations whose members all share the same cephalic index. Even worse tor the poor craniometers, the skull shape of the children of immigrants to America shifted away from that of their parents towards that of people already there. Its shape is in any case affected by natural selection. Populations from hot places as far apart as Africa and Malaya have similar skull form, which differs from that of Scandinavians or Eskimos. Even if they have different ancestry, they have converged to about the same shape. Natural selection means that shared heads do not prove common homelands.

So obvious seemed the differences between groups that scientists were blinded to their own results. Samuel George Morton in his Crania Americana of 1830 measured hundreds of skulls. The differences were, he thought, clear: Caucasians had larger brain cases than Mongolians and Malays, who in their turn were better endowed than Africans and Europeans. When the same specimens were re-measured with modern instruments the differences disappeared. Morton's results were due to the omission of some groups which did not fit his ideas, confusion of males and females, and a failure to correct skull size for differences in body size.

Even so, early workers had enormous confidence in the value of skull shape. Such measurements were used by the Nazis in an attempt to sort out those with Jewish ancestry. The Frenchman Georges Vacher de Lapouge who wrote in 1887 ^lI am convinced that in the next century millions will cut each others* throats because of one or two degrees  more or less of cephalic index' was more correct than he feared.

Races could also be classified by language. The term 'Aryan', which gained such sinister overtones, came from the idea of a talented people, the Arya, who migrated from a homeland somewhere in the east, bringing their inheritance and their language with them. The French writer Joseph Gobineau, the father of modern racist ideology, in his 1854 'Essay on the Inequality of Human Races' wrote that 'Everything great, fruitful and noble in the work of man on this earth springs from the great Aryan family'. He persuaded himself that the Aryans had spread to found the cultures of ancient Egypt, Rome, China and even Peru and that 'all civilisations derive from the white race'.

Thor Heyerdahl's famous voyage across the Pacific in search of the founders of the civilisations of Polynesia can be traced back to Gobineau. They gave rise to a long series of attempts to trace historical links among cultures (such as those of the Celts and the Incas) which share sun-worship, massive stone monuments, and mummies. All were supposed to descend from the Aryans, who were often equated with the ancient Egyptians.

Anthropology is the study of the movement of peoples, genes and cultures. These were once all assumed to be the same thing. To observe one's fellow citizens makes it obvious even to an anthropologist that everyone does not belong to a single racial type: people look different. Difference usually means classification and from there it is a riny step to judgement. The early evolutionists did not hesitate. Blumenbach, who coined the term 'Caucasian', was glad to show where his sympathies lay. Part of his definition was '. the most beautiful race of men.. Nature has lavished upon the women beauties which are not to be seen elsewhere. I consider it impossible to look at them without loving them.. ' Even Rousseau never suggested that the noble savage was black.

Ninety per cent of the names given to themselves by tribal peoples mean 'men', 'the only men', or 'the best men'; that is, we are human, others less so. The Sioux Indians of North America seem to he an exception. The literal translation of 'Sioux'¹ is snake, or enemy. In fact, this name was given to them by an adjacent tribe (and picked up by the first French settlers). The Sioux themselves call their tribe the 'Lakota' — the humans.

The idea that humanity was divided into distinct lineages of different quality had a disastrous impact. The tie of the philosophy and policies of the Nazis to anthropology, and the desire to return to a lost time of pure races, is clear. The Gesellschaft fur Rassenhygien (Society for Race Hygiene) was founded in 1905. By 1908 all mixed marriages in German South-West Africa (now Namibia) were annulled and those involved in them deprived of their citizenship. Haeckel himself, the champion of The Origin of Species., wrote that 'The morphological differences between two generally recognised species — for example between sheep and goats — are much less important than those between a Hottentot and a man of the Teutonic race.¹ His philosophy ended in disaster.

The ties between biology and the politics of difference that began before Hitler were not broken until many years after his death. Until 1913 the Statue of Liberty really did welcome, as its inscription says, the huddled masses, struggling to be free. In his 1916 book The Passing of the Great Race the euphonious American, Madison Grant, echoed many of his fellows when he complained that alien races were being grafted onto the nation's racial stock. With the advice of biologists, President Coolidge was moved to say that 'biological laws tell us that certain divergent peoples will not mix or blend. The Nordics propagate  themselves successfully. With other races, the outcome shows deterioration on both sides.'

After determined genctical lobbying, the first Immigration Act was passed in 1924. It set limits to ensure that the ethnic composition of the USA stayed at what it had been in the late nineteenth century. Each country was allowed quota of two per cent of the numbers of its citizens present in the United States in 1890 (when most of that nation's people were from the British Isles, Scandinavia and Germany). The law was very good at keeping Eastern Europeans out and left many to the mercies of the other experiment in race hygiene which soon began there. It was not repealed until 1966. The theory of pure races had cast a long shadow. Its spectre has not yet disappeared. A Hungarian political party campaigned against rights for gypsies in the nineteen-nineties as they were 'a disadvan-taged group, to whom the laws of natural selection have not been applied.'