Did you know that the person who discovers “color blindness” is actually a color blind person

John Dalton, is the British modern great physicist, chemist, modern atomic theory of the proposer, is also recognized as the father of modern chemistry, was rated as one of the world process of the 100 celebrities. Dalton has a wide range of interests in natural science, not only in the chemistry of this subject has made great achievements, but also in meteorology, physics, mathematics and other disciplines have obtained a lot of research results.

He published more than 100 papers in all, but his first formal paper was on color blindness, and it was on himself, not small animals or anyone else.

约翰·道尔顿,英国伟大的化学家、物理学家,也是世界上首个对色盲这种视觉缺陷进行详尽描述的科学家
John Dalton, the great British chemist and physicist, was also the first scientist in the world to describe in detail this visual defect, color blindness

John Dalton was born in Eaglesfield, Cumberland, England in 1766. His father was a farmer, and his mother was a peddler of ink, quills and paper. Although the family is poor, Dalton is smart and hard working since childhood. He is highly regarded by his teacher Robinson, who provides a lot of support for Dalton. At the age of 12, Dalton became a junior teacher, from which he could earn a small income to support the family.

In 1793, at the age of 27, he began a job as professor of mathematics and natural philosophy at New College, Manchester. In October 1794, he became a member of Manchester Society of Literature and Philosophy. At the same time, he published his first formal paper: Extraordinary Facts relating to the Vision of Colours in the seminar of the Society. With obsevations “.

It was the first paper ever to describe and discuss color blindness in detail, and it was Dalton himself who was the subject of his research. How did Dalton find out he had color blindness?

Extraordinary facts relating to the vision of colours | Association des  amis de la Bibliothèque nationale de France
The paper, published in 1798 in the Memorial Journal of the Manchester Literary and Philosophical Society, was the first detailed description of color blindness

The day I discovered color blindness

There are many different accounts of how Dalton discovered he was colorblind, but one of the most popular stories is that Dalton bought socks for his mother. Once, Dalton’s mother’s birthday, Dalton decided to choose a socks for his mother as a gift. Dalton picked out a dark gray pair of socks for his mother, but when he gave them away, she was surprised that Dalton had given her a pair of bright red socks.

Dalton came from a Quaker family and was strictly observant of religious rules and doctrines, believers who thought it inappropriate to wear bright red socks. Everyone thought Dalton was joking, but Dalton was confused. He discovered that his vision was different from other people’s, and set out to study his color blindness.

This version of the story is widely circulated, but it is not, in fact, how Dalton discovered that he was colorblind. In his essay, Dalton described his accidental discovery that he was color-blind.

For a long time Dalton had been vaguely aware that the colors he was seeing were different, but he had not bothered too much about it. After all, our Mr. Dalton doesn’t wear lipstick. He doesn’t need to know the difference between red, saffron, crimson and brown.

But starting in 1970, Dalton began to study botany. Yes, these high-achieving students have a wide range of interests. After studying botany, Dalton had to work with color frequently. At this point, he clearly sensed that he was having some problems with color discrimination. He used to ask people seriously whether a flower was pink or blue, but the question was often confused and thought it was just a joke on Dalton’s part, and no one ever answered his question directly.

Then, one night in 1972, he was surprised to discover that there was something wrong with his vision.

‘The geranium is a pink flower. During the day it looked sky blue to me, but by candlelight I was surprised to see that it turned yellow to my eyes. I was sure there was something wrong with my vision.

That’s amazing. He also discovered that one of his brothers had the same problem — they would see the same object as two different colors when it was in daylight and when it was in candlelight at night.

Dalton’s scientific soul was instantly ablaze, and he realized that there was a lot to be said for this question.

Dalton then began to focus on the study of this strange phenomenon. He asked his relatives, friends and students to identify the spectrum of the sun. Dalton found that normal people can distinguish between six colours — red, orange, yellow, green, blue and purple. But for himself he could only see three colours — yellow, blue and purple.

In his paper, Dalton also described in detail how he felt about different colors during the day and by candlelight. He found himself confused about red and green. During the day, crimson, crimson, and crimson were dark blue or dark brown in his eyes; At night, red is like a shadow. But the blue and purple he saw were the same as normal people.

He also found that two of his students had the same problem, and noted in his paper that he had never heard of such problems in women. In fact, the incidence of color blindness in men is indeed much higher than that in women (about 5%~8% in men and less than 1% in women).

Dalton speculated that the cause of the disease might be in the eyeball, which he thought might be unable to see red and green light, causing him to be unable to perceive those colors. Therefore, he made a will in his lifetime, after his death to donate his eyes to the medical school, for the study of the cause of color blindness. After his death, his good friend and pupil, Dr Ransome, performed an autopsy on one of his eyeballs. But unfortunately, given the medical skills of the time, Dr. Ransome could not find anything unusual in Dalton’s eye. It wasn’t until 1995 that scientists extracted DNA from Dalton’s other surviving eye, which, after genetic analysis, proved that Dalton had red-green blindness.

So what causes color blindness? Is it really the eyeball problem that Dalton thinks it is?

Dalton’s disease — color blindness

Now, medical scientists have found the cause of color blindness. Color blindness is not related to the light transmittance of the eyeball. The cause of color blindness is actually located in the retina at the back of the eyeball. In our retinas, there are two different types of visual cells, called rods and cones. The rods, whose main job is to sense light, and the cones, whose main job is to distinguish color, are the cells that make our world so colorful.

Functional anatomy of the retina. Metabolic interactions in the retina... |  Download Scientific Diagram
Retinal anatomy and stratification

Rod and cone cells are two important types of cells in the retina. They are so named because the former is columnar and the latter is cone-shaped. The two types of cells perform different functions in visual imaging

Cones are divided into several subtypes, depending on how sensitive they are to different wavelengths of light. There are three main subtypes of cones in humans that are sensitive to long-wave (red), medium-wave (green) and short-wave (blue) light. Just as in painting, the three cones work together to create a colorful world by changing the ratio of red, blue and green pigments to produce different colors.

CONE CELLS- Cone cells are at the heart of our color perception; they  selectively respond to specific colors. There are three type… | Cone cell,  Color theory, Color
Three different subtypes of cones

In color-blindness, one or more of the cones has a problem, which prevents the sufferer from seeing some or all colors.

After the invention of modern gene technology, scientists through genetic testing, found that color blindness is a genetic disease associated with sex. It is generally believed that red-green color blindness is determined by two pairs of genes on the X chromosome, namely the red-color blindness gene and the green-color blindness gene. Red-green color blindness is inherited with X chromosome recessive inheritance. Based on this genetic pattern, there are far more men than women with color blindness. In China, the prevalence of color blindness is as high as 8% in men and about 0.5% in women.

Although the disorder had been written about before Dalton, Dalton was the first to describe it in detail and to study it scientifically, so color blindness is also called Dalton’s disease in honor of Dalton’s work. After the invention of modern gene technology, scientists through genetic testing, found that color blindness is a genetic disease associated with sex. It is generally believed that red-green color blindness is determined by two pairs of genes on the X chromosome, namely the red-color blindness gene and the green-color blindness gene. Red-green color blindness is inherited with X chromosome recessive inheritance. Based on this genetic pattern, there are far more men than women with color blindness. In China, the prevalence of color blindness is as high as 8% in men and about 0.5% in women.

So how did color blindness affect Dalton on his scientific path?

Color-blind and Dalton

Now, many professions have certain restrictions on patients with color blindness and color weakness. For example, according to the regulations, patients with color blindness and color weakness can not apply for painting, art, chemical engineering and other majors in the college entrance examination. Dalton, the father of modern chemistry, would not have been able to study chemistry at university. Thankfully, color blindness was unknown at the time, or modern chemistry would have missed one of its great founders.

As a young man, Dalton met a mentor who was crucial to his scientific career — the blind scientist and philosopher Hauff. Hauff lost his sight due to smallpox when he was young, but he still mastered a wealth of scientific knowledge through hard work and was even able to complete many scientific experiments on his own. Hauff had a profound influence on Dalton. On the one hand, he taught Dalton a great deal of scientific knowledge. Under Hauff’s guidance, Dalton studied French, Latin, mathematics, natural sciences and philosophy. More importantly, Hauff, who also had eye problems, imbued Dalton with tenacity and perseverance.

Apart from his first paper, Dalton has hardly complained about the effects of color blindness on his scientific work. Fourteenyears after he discovered he was colorblind, his magnum opus on chemistry, The New System of Chemical Philosophy, was published. In it, he detailed the main theories and experiments of atomism. Dalton’s theory of atoms opened the door to modern chemistry.

Manchester public art: John Dalton outside Manchester Metropolitan  University - Manchester Evening News
A statue of Dalton stands in Manchester City Hall

In Dalton’s youth, color blindness, a physical defect, had instead inspired his scientific passion, which led to meticulous research and his first paper; In his later years, however, Dalton became rigid and extremely opinionated, rejecting Gay-Lussac’s partial volume law for gases, insisting on his own atomic weight rather than data that had already been measured accurately, and opposing the simple system of chemical symbols proposed by Yonse Jacob Berzelius. By refusing to accept new scientific advances, Bolton wrongly denied the scientific achievements of others and missed the opportunity to achieve greater achievements.

Obviously, it is not physical defects that prevent one from achieving great achievements in scientific research, but rigid thinking that is the greatest enemy of scientific progress.