The photos that reveal the horror of eugenics: Disturbing images document a time when those with undesirable genetic traits were sterilised or killed in order to 'cleanse' society.

The photos that reveal the horror of eugenics: Disturbing images document a time when those with undesirable genetic traits were sterilised or killed in order to 'cleanse' society.

These are the horrifying photos from the heyday of the Eugenics movement that the world wants to forget.

Before the atrocities of Nazi Germany, eugenics - the system of measuring human traits, seeking out the desirable ones and cutting out the undesirable ones - was once practised the world over.

In the decades following the 1859 publication of Charles Darwin's 'On the Origin of Species', a veritable craze for eugenics spread through Britain, the United States and Europe.

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In the decades following the 1859 publication of Charles Darwin's 'On the Origin of Species', a veritable craze for eugenics spread through Britain, the United States and Europe.

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Bruno Beger was a German racial anthropologist who worked for the Ahnenerbe, a project in Nazi Germany to research the archaeological and cultural history of the Aryan race. In this image taken in 1938, Dr Beger is measuring a Tibetan woman's head to demonstrate what he believed were the 'inferior' characteristics of her race

Bruno Beger was a German racial anthropologist who worked for the Ahnenerbe, a project in Nazi Germany to research the archaeological and cultural history of the Aryan race. In this image taken in 1938, Dr Beger is measuring a Tibetan woman's head to demonstrate what he believed were the 'inferior' characteristics of her race

These images have been released today from the the Library of Congress archive. 

Advocates of eugenics made significant advances during the early twentieth century - and claimed that 'undesirable' genetic traits such as dwarfism, deafness and even minor defects like a cleft palate needed to be wiped out of the gene pool.

Scientists would measure the human skulls of felons in an effort to eradicate criminality - whilst other eugenic proponents suggested simply cutting out entire groups of people because of the colour of their skin.

The first sterilisation law - which stopped certain categories of disabled people from having children - was passed in Indiana, USA in 1907. 

This was twenty-six years before a similar law was introduced by the Nazis in Germany in 1933. 

In fact, in their sterilisation propaganda, the Nazis pointed to the precedent set by America.

In one haunting image from 1912, a British family of children born with rickets is photographed by the Eugenics Society to demonstrate that their condition is hereditary and could be controlled through selective breeding.

British Sir Francis Galton - a cousin of Charles Darwin -became obsessed with Origin of Species and coined the term 'Eugenics' in 1883. 

He believed that breeding humans with superior mental and physical traits was essential to the well-being of society as a whole, writing 'Eugenics is the science which deals with all influences which improve the inborn qualities of a race; also with those which develop them to the utmost advantage.'

Galton was knighted for his scientific contributions and his writings played a key role in launching the eugenics movement in the UK and America.

In 1907, the eugenics Education Society was founded in Britain to campaign for sterilisation and marriage restrictions for the weak to prevent the degeneration of Britain's population.  

In 1931, Labour MP Archibald Church proposed a bill for the compulsory sterilisation of certain categories of 'mental patient' in Parliament.  

Meanwhile from 1907 in the United States, men, women and children who were deemed 'insane, idiotic, imbecile, feebleminded or epileptic' were forcibly sterilised, often without being informed of what was being done to them.

By 1938, 33 American states permitted the forced sterilisation of women with learning disabilities and 29 American states had passed compulsory sterilisation laws covering people who were thought to have genetic conditions.

All legislation was eventually repealed in the 1940s.

The New York City Police Department demonstrates how to measure a criminal's cranium in New York City, New York in 1908. From 1907 in the United States, men, women and children who were deemed 'insane, idiotic, imbecile, feebleminded or epileptic' were forcibly sterilised, often without being informed of what was being done to them

Researchers measure the capacity of a human skull by filling it with water in the National Academy of Sciences in 1885

Pictured is an image of a human skull taken from the same year. After the publication of Charles Darwin's 'On the Origin of Species', a veritable craze for eugenics spread through Britain, the United States and Europe

In 1907, the Eugenics Education Society was founded in Britain to campaign for sterilisation and marriage restrictions for the weak to prevent the degeneration of Britain's population. 

A year later, Sir James Crichton-Brown, giving evidence before the 1908 Royal Commission on the Care and Control of the Feeble-Minded, recommended the compulsory sterilisation of those with learning disabilities and mental illness - an act that Sir Winston Churchill supported.

Although such legislation was never actually passed in Britain, this did not prevent many sterilisations being carried out under various forms of coercion.

Meanwhile from 1907 in the United States, men, women and children who were deemed 'insane, idiotic, imbecile, feebleminded or epileptic' were forcibly sterilised, often without being informed of what was being done to them.

By 1938, 33 American states permitted the forced sterilisation of women with learning disabilities and 29 American states had passed compulsory sterilisation laws covering people who were thought to have genetic conditions. Laws in America also restricted the right of certain disabled people to marry.

Sometimes, however, things went even further. 

A mental institution in Illinois euthanized its patients by deliberately infecting them with tuberculosis, an act they justified as a mercy killing that cut the weak link in the human race. 

Other countries which passed similar sterilisation laws in the 1920s and 30s included Sweden, Denmark, Norway and Finland.

After these kinds of ideas took root in Nazi Germany and sparked the horrors of the Holocaust, eugenics turned into a dirty word. 

With the dark conclusion of its philosophy exposed before the world, it became difficult to justify forced sterilization as a tool for the greater good.

All legislation was eventually repealed in the 1940s - and history was then subtly rewritten, with eugenics discussed as something that the Germans did and from which the rest of the world could wash its hands clean.