John Dalton’s Anomalous Color Vision

John Dalton is far more famous for his work in atomic theory. But he wrote one of the first thorough descriptions of what he called “anomalous vision” – meaning that he realized he wasn’t perceiving color the same way as other people. 

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Episode Transcript

Speaker 1 (00:01):
Welcome to Stuff You Missed in History Class, a production
of I Heart Radio. Hello, and welcome to the podcast.
I'm Holly Fry, and I'm Tracy Vie Wilson. Tracy, I
bet this happened to you. I know it happened to me.
Like you must have had those moments as a child

(00:23):
where you thought you were being very insightful. I know
I certainly did where I was like, how do I
know that what I see is the same thing as
other people see? I had this exact Yes. Yes, I
also asked my mom one time. I was like, Mom,
how do how do we know that what I see
as green is the same thing as what you see
as green? Uh? And my mom, stay at home mom

(00:47):
with two little children, did not always have a lot
of patients for weird questions. And she was like, it's
the same. I'm not trying to drag my mom in
any way. I'm know of our creativity and attentive to
our but yeah, this was a case where I liked
I just asked her a question she was not prepared

(01:08):
for question time. Here is the thing. I asked the
same question of my father, who I did not know,
and I don't know that he knew at the time
did not see color the way, so so he was
trying to describe things, and I just remember, I mean,

(01:31):
I was probably like seven or eight, already kind of
a smart alic, and I was just like, okay, this
is going nowhere. I'm out. So maybe just saying green
is green was a really a better route because that
led to a lot of confusion in our lives, um
for a moment, until we finally put the pieces together right.
And really what happened was that. And I don't mean
to drag my father, but like he was career military,

(01:51):
so um, he's now retired, but his clothes were like
sort of prescribed for sure. When he stopped up being
constantly on active duty and started picking out his own clothes,
some things became readily apparent, which is that that does
not go together. My dude, Yes, they look they're practically

(02:12):
the same color. Oh, we should address this, right. That's
we never knew for years, when you're wearing like jeans
and a plaid shirt in your off time and then
a uniform the rest of the time, it would never
come up. Now we learned. But this curiosity about whether
other people see the way that you see is really

(02:32):
what drives a lot of scientific discovery. Uh And we
are talking about somebody who was curious and did a
lot of scientific discovery. But in the case of this subject,
who was very well known and respected in his day,
he just didn't think about how he or anyone else
saw color until he kind of stumbled into it while
studying plants and realizing that his vision might be different

(02:55):
from other people. And that's John Dalton. And really John
Dalton is far more famous for his work in atomic
theory and which builds the foundations of organic chemistry, but
he also wrote one of the first really thorough descriptions
of what he called anomalous vision, meaning that he realized
he was not perceiving color in the same way as
other people. And his descriptions are very entertaining. We're going

(03:19):
to read some of them. Uh So today we will
talk a little bit about his life, but mostly about
this sort of pocket in his scientific work, where he
made a brief foray into exploring the world of photoreceptors
and color perception, although he didn't use those words for it.
Color blindness is a term that's falling out of favor
because it's not really accurate color blind suggests that somebody

(03:42):
can't see color at all. But most people who have
historically been diagnosed with color blindness can see colors, they
just see them differently. So defective color vision or color
vision deficiency are becoming more preferred terms. I feel like
I see people describing them selves as color blind still
quite a lot, So this is something that's evolving. We're

(04:05):
still kind of at the beginning of the scientific community
shifting to these different terms just and it's really about
clarity more than anything else, right, Like, now you do
see color. We'll talk about one exception, but just differently.
So we need to make a clearer term for it
that's not misleading. And color vision deficiency is the inability

(04:26):
to distinguish specific colors red, green, and blue, and to
be diagnosed as color blind historically or color vision deficient. Now,
a person only needs to have an inability to distinguish
one of these colors, but it is possible for someone
who has color vision deficiency to be unable to distinguish
all three. So in your retina, you have cells called rods,

(04:49):
which perceive light, and then three types of cells called cones.
Cones are really the important factor. Here. They are the
photoreceptive cells that enable us to perceive color. The human
retina contains six million cones. Red sensing cones make up
sixty of the total number of cone cells, green sensing

(05:11):
cones make up and blue sensing tones make up the
remaining ten. So if all of your cone cells are
functioning normally, you are said to have trichromacy, meaning you
can see three try of these colors and they combine
to create standard vision. But it is also possible to
have dichromacy with only two types of cone cells present

(05:32):
or functioning, or even monochromacy where only one type of
cone is functioning. Monochromacy is a little bit tricky because
it can also be used to describe a scenario where
none of a person's cones are functioning, and a person
who has monochromacy may have other vision issues as well,
And monochromacy that we just talked about with no cone
function is kind of the one variation in all of

(05:54):
this where the color blind label would be actually pretty accurate,
because everything to them appears not in the rainbow of colors,
but as a shade of gray most of the time.
Dichromacy manifests itself in a way that a person can't
see a difference between red and green, and dichromacy of
this nature is broken down into separate classifications based on

(06:16):
which types of cones do and don't work in a
person's retina. Protnopia describes a state of not being able
to see red, and due to anopia is a case
where the red cones functioned but the green cones do not.
Blue yellow color deficiency, which is a little rarer, is
similarly broken down into classifications based on its specific nature

(06:37):
in a given person. So someone with a lack of
blue cones is said to have tritenopia, and if they
have blue cones but reduced sensitivity to that color, it
is actually described as trite Anomally, and all color vision
deficiency can fall on a spectrum. Some people have a
diminished ability to distinguish red from green, for example, but

(06:58):
they're able to see difference then specific shades of these colors. Yeah,
sometimes you know, people can't hit the lighter tones of
the darker tones get real muddy, but they can see
different shades. It's it's all. It manifests in many different
ways and in the United States and estimated five to
ten of the population have some form of color vision deficiency.

(07:20):
Usually this gets tested for when people are kids, and
more boys than girls have colored vision deficiency, and the
percentage shifts based on race. So there was a twenty
fourteen study that gets cited a lot uh. This was
published in the journal Optimology, and it had taken studies
of the color vision of four thousand California children ranging

(07:41):
in age from three to six. And in this study
it was found that among the girls, less than half
a percent of them exhibited signs of color vision deficiency
regardless of race, but in boys the numbers were different.
Six percent of the white boys in the study were
diagnosed with color vision deficiency, three percent of the Asian
boy had some form of color vision deficiency. It was

(08:02):
found in fewer than three percent of the Latino boys
and less than two percent of black boys. Genetically, boys
are more likely to have red green color vision deficiency
because they only need to inherit it from their mother.
It is a recessive characteristic that's associated with the X chromosome.

(08:23):
So if a female inherits the trait from her mother
but not her father, she'll generally have normal color vision.
She only has that one X chromosome, but then she
could pass a trait onto her own children. And this
is different from blue yellow color vision deficiency, which is
a dominant characteristic, and so that only needs to be

(08:45):
inherited from one parent, and it is not linked to
a person's sex. I'm just gonna say these are related
to sex and not to gender. That's the different thing. Yeah,
we're going with kind of that twenty fourteen studies separation
of boys and girls, which simplifies the whole discussion, and
is sex assigned at birth not necessarily? How if they

(09:09):
did that, I would be fascinated if they did the
same exact test today and how they would break it out,
because it's things have shifted a bit um. So if
anybody knows of any studies similar to that going on today,
I'm very curious. But here's the thing. You're probably wondering,
how we figured all of this out? Uh. And in
the late eighteenth century, this idea of people perceiving color

(09:30):
differently than most humans was certainly not unknown. King George
the Third, for example, reportedly discussed this with an English novelist,
Fannie Bernie at court in seventeen eighty five, and there
were some theories about what caused color vision anomalies published
in Germany in the late seventeen hundreds, but the first
systematic analysis of color vision deficiency appears in seventeen at

(09:53):
least the first that we know of, and that brings
us to the person we mentioned at the top of
the show, John Dalton. John Dalton was born in early
September seventeen sixty six. His actual date of birth is
either September five or September six. His parents, Joseph Dalton
and Deborah green Up Dalton, were Quakers. His father made
a living as a weaver. The Dalton's had three children

(10:16):
who lived to adulthood, and John was the youngest of them.
And as a child, John attended a Quaker school, and
that school changed hands when John was twelve. John Fletcher,
the man who had been running it, gave it to
John Dalton's older brother, Jonathan Dalton, and then Jonathan enlisted
John's assistance in this new role, and this set John

(10:36):
on a path as an educator. Just kind of delights
me that they had a John and a Jonathan. It
makes me giggle as well. John and Jonathan expanded their
new careers by taking over a school in Kendall, England,
when John was just fourteen. This is a larger operation
than the Quaker grammar school they had been running, and

(10:57):
it included students who boarded as well as students. Has
totaled about five dozen students in all, and John was
sort of learning on a job. He was studying with
scholars to learn math, Latin, Greek and science to stay
ahead of his students and to be able to speak
on the subjects of their curriculum. And keep in mind,
again he's like fourteen fifteen at this fight, uh, so

(11:21):
he is taking in a lot of information. And he
stayed in that job for a dozen years and then
at the age of twenty seven, John moved on to
a new professional post as a mathematics teacher at New College,
and this was in Manchester. And he found all this
a little bit frustrating though, because his workload in that
job prevented him from having time to pursue his own
scientific study. So he switched gears and decided that he

(11:44):
would become a private tutor so that he could manage
his own time in a way that would enable him
to carry on with his side work. At this point,
his work outside of his daily teaching task was focused
largely on meteorology. He had been publishing articles in the
subject for several years, but he kept studying other sciences
as well and all and it was through these studies

(12:06):
that he wound up writing a paper that expounded on
the idea that not everyone saw colors in the same way.
So this was not the first time the mention of
non standard color vision appeared in print. As we said earlier, surely,
color vision divisiency has been in play almost as long
as humans have existed, and even before Dalton there had

(12:27):
been some mentions of it, including a write up of
a man named Thomas Harris that was published in Philosophical
Transactions and that described Harris's inability to distinguish colors, which
was published in seventeen seventy seven. We're gonna come back
to Harris, and we'll talk first more about John Dalton,
but before we do all of that, we're going to
pause for a brief sponsor break. John Dalton presented his paper,

(12:57):
which was titled Extraordinary Facts relating to the s of
Colors with Observations by Mr John Dalton, at Manchester's Literary
and Philosophical Society on October. He had joined the society
upon moving to Manchester. And as scientific papers go, this
one is kind of unique in that Dalton himself is
really the subject of the paper, or at least his

(13:19):
vision was. That text opens with quote, it has been
observed that our ideas of colors sounds, tastes, et cetera,
excited by the same object, may be very different in
themselves without our being aware of it. He goes on,
quote I was always of the opinion, though I might
not often mention it, that several colors were injudiciously named.

(13:44):
The term pink, in reference to the flower of that name,
seemed proper enough. But when the term red was substituted
for pink, I thought it highly improper. It should have
been blue in my apprehension, as pink and blue appear
to me very nearly allied, whilst pink and red have
scarcely any relation. He goes on in his introduction to

(14:09):
mention how he had learned about light and optics in
his scientific studies, but he hadn't really thought about applying
any of that information to colors, because that entire area
the idea of color seemed kind of confused, And on
to them like he really was, like, why would people
group these colors together? Doesn't make any sense, But I
guess that's how we've always done it. Uh. It was
not until he turned his scientific work to botany that

(14:32):
he really started thinking about why some color groupings just
made no sense. And this study prompted him to ask
other people questions about colors. He actually uses the example
in this paper of asking a person whether a flower
was blue or pink. But they always just thought he
must be joking because the queries came off as so
completely absurd to them. So he just thought everybody had

(14:54):
this weird relationship with color. Even though he thought colors
made no sense, it didn't really occur to him to
wonder if there was something unusual about the way he
was perceiving colors. It was a moment in seventeen ninety two,
two years before he presented his paper, that really gave
him this moment of pause. That moment happened when he

(15:17):
was looking at a geranium by candle light. So he
had frequently seen these flowers, this particular variety he was
looking at were in fact pink in daylight, and to him,
in daylight he perceived them as sky blue, but by
candle light, he saw this flower as a vibrant red,
and this significant shift in their color due to lighting

(15:38):
changes startled him and led him to make a quick
study by asking a number of friends to look at
these same flowers in both daylight and candle light. All
the people he initially asked about it saw them as
pink in both lighting conditions, except for his brother, who
perceived that same shift of them being sky blue in
the day and red in candle light. This experience caused

(16:01):
him to start a more structured study of light and color,
which he did with an assistant who had quote normal
color vision. First, he used a prism to project sunlight
into a dark room and then recorded the number of
colors that various people saw in that band of light.
Most of them saw six red, orange, yellow, green, blue,

(16:22):
and purple. He does mention that purple is separated into
indigo in violet and Newton's writings on color for the
purposes of a person simply looking at a band of light,
that distinction is really nominal. I think we talked about
this in one of our episodes that touched on Newton. Previously.
He put the indigo and violet in their separately because
he wanted there to be seven. So that's why people

(16:46):
typically don't actually see them. As to the state shades
in light from a prism, yeah, or you'll see what
you think is maybe a slight difference, but it's hard
to be sure. So for for Dalton, he just called
that one thing, it's purple. Uh. When Dalton looked at
the prismatic light, though, he could only make out two
or sometimes three colors, so generally he just saw yellow

(17:10):
and blue, or sometimes he would see yellow, blue, and
a little bit of purple. And through his work he
identified that the band that he saw is yellow was
where other people were seeing red, orange, yellow, and green,
and he wrote quote that part of the image, which
others call red, appears to me little more than a
shade or a defective light. After that, the orange, yellow,

(17:32):
and green seemed one color which descends pretty uniformly from
an intense to a rare yellow, making what I should
call different shades of yellow. Dalton's perception of blue and
purple aligned with what other people were seeing, and the
contrast between the end of his band of yellow and
the adjacent blue was really sharp. So next he did

(17:53):
the same collecting of perceptions from himself and others when
looking at candle light projected through a prism, and these
results were mostly the same. The only exception that Dalton
calls out is that for him, the red edge of
the image looks more vivid in candle light than it
did looking at some light under the same conditions of
being put through a prism. Dalton's paper next breaks out

(18:16):
studies of specific colors as he had always perceived them.
He starts out by describing colors grouped with red as
they appear in the daylight versus candle light. His description
of crimson is pretty charming quote Crimson has a grave appearance,
being the reverse of every showy and splendid color. A

(18:37):
similarly quaint description this is a description of pink. He
breaks that down as nine parts light blue and one
part red quote or some other color which has no
other effect than to make the light blue appear dull
and faded a little. He also lists out all the
flowers that to him look blue to give the reader

(18:57):
a sense of context. When he says he says pinks
and reds as blue. Blood, he says appears to him
as the color most people call bottle green, and he
mentions that if he saw a light colored stocking that
was spattered with either fresh blood or dirt, he would
not be able to tell the difference visually. I love

(19:18):
this entire paper so much. It's exactly like this. The
way through his his turn of phrases, quite quite charming
and endearing, He goes on to describe the significant change
that red undergoes for him when viewed in candle light.
He describes it as much more vivid, and the blue
no longer being present and instead replaced by yellow tones.

(19:40):
While he found most reds and pinks quite drabbed by daylight,
in kindle light they became really vivid and even exciting.
Orange and yellow, he says, are not too different for
him than anyone else. When he moves on to discussing green,
he writes, quote, I take my standard idea from grass.
This appear is to me very little different from red.

(20:02):
The face of a laurel leaf is a good match
to a stick of ceiling wax, and so it will
be immediately concluded that I see either red or green,
or both different from other people. The fact is, I
believe that they both appear different to me from what
they do to others. He concludes that blues he generally

(20:23):
sees the same as other people, and purple is just
a little bit different from blue. He described brown in
the same creative way that he does other colors, writing quote,
my idea of brown I obtained from a piece of
white paper heated almost to ignition. He also notes that
seeing colors in moonlight presents the same or near same

(20:44):
results for him as seeing them in candlelight. Lightning gives
the same effect as daylight. It doesn't matter whether the
sun is rising or setting when it comes to color,
and any kind of combustible substance creates the same color
perception as any other flame. He concludes the section of
the paper with quote, my vision has always been as

(21:05):
it is now. His next section breaks out the information
that he's collected from other people and their perceptions of color,
starting with people he has found who have vision that
seems similar to his own, and Dalton mentions Mr Harris
of Maryport and his alternate perceptions of color. Dalton thought that,
based on the description, Harris's anomalous vision might have been

(21:29):
different from his own. He discovered that one of Harris's
brothers was still alive, so he made contact and went
to visit. Upon questioning this brother and testing his vision,
Dalton found that the Harris family seemed to have the
same genetic variable that he and his brother had when
it came to how they perceived the colors of the
world around them. This led to a general line of

(21:51):
questioning of the students and colleagues that Dalton regularly came
in contact with, kind of as a subject group, and
he found a small proportion of them share his specific
experience regarding pink and light blue looking similar by daylight
and different by candle light. Dalton also found just a
couple of examples of people who quote differ from the
generality and from us, also meaning that they seem to

(22:14):
have a different type of color vision deficiency. He also
mentioned a shared experience among all of these people that
justice with him it had not occurred to them that
they were seeing things differently from the majority of people,
but that they too found the names and groupings of
colors perplexing at times. Though his paper was really the
beginning of sciences study of color vision deficiency, even in

(22:38):
his really relatively small data set, Dalton was already capturing
information that showed a difference in instances of color vision
deficiency in regards to people's sex. He noted that in
the Harris family, four of six sons in the family
had what would come to be known as color vision deficiency,
sometimes also called dalton is um for obvious reason, but

(23:00):
their sister didn't. Similarly, Dalton and his brother Jonathan had
the same color experience, but their sister did not. He wrote, quote,
it is remarkable, but I have not heard of one
female subject to this peculiarity. He also included the line
quote I did not find that the parents or children
in any of these instances have been so unless in

(23:22):
one case. So, even though he didn't really realize it,
he was gathering information on the recessive genetic nature of
red green color vision deficiency. Next up, we'll talk about
what Dalton thought was causing his anomalous vision, but first
we will take a break for a word from our sponsors.

(23:46):
The third section of Dalton's paper tries to unravel the
cause of what he was referring to as quote our
anomalous vision. One of the ways that he worked out
his theory here was to work with transparent colored liquids,
and then he would have various people look at objects
through those transparent colored liquids to record their perception of color.

(24:07):
So he would hold up a thing behind, like a
tank of blue water, whatever um and ask them what
they saw. And because people with you know, quote unquote
normal vision described color similar to what he saw in
his normal day to day life when they looked through
a tank of blue water, he came to this incorrect
conclusion that quote, one of the humors of my eye

(24:29):
must be a transparent but colored medium, so constituted as
to absorb red and green rays principally because I obtain
no proper idea of these in the solar spectrum, and
to transmit blue and other colors more perfectly. Honestly, this
is a totally reasonable conclusion based on understanding. Right. He

(24:53):
outlined how this would impact the perception of various colors,
and then addressed why the colors changed so dressed for
him and other others like him. In candlelight, writing quote,
when any kind of light is less abundant in blue,
as is the case with candle light compared to daylight,
our eyes serve in some degree to temper that light

(25:14):
so as to reduce it nearly to the common standard.
The Earth's atmosphere, he believed was a blue fluid that
quote modifies the Sun's light so as to occasion the
commonly perceived difference. So this paper was met with some curiosity,
and his very detailed comparisons of his vision to that

(25:34):
of other people who saw color normally offered a lot
of insights. But this idea of a blue humor in
his eye that was causing his anomalous color vision was
kind of dismissed by the scientific community, and in response, Dalton,
who really thought he was onto something with it, donated
his eyes to science. He wrote up a document that

(25:54):
requested that his eyes be dissected upon his death to
see if he had been correct and whether there was
any other physical evidence to explain the way he perceived color.
A little less than a decade after Dalton's writing on
his anomalous vision, scientist Thomas Young published on the theory
of light and colors, and this put forth the idea

(26:15):
that there were receptors in the eye for each of
the colors red, green, and blue. So he was totally
onto it, and Young addressed Dalton's work and his anomalous
color vision with a different theory that there was a
quote absence or paralysis of those fibers of the retina
which are calculated to perceive red. He was so completely

(26:37):
on the right track that you would think that this
would have just broken eye science wide open. But no, no,
it advancement slowed down after this and studying the eye
and that went on for decades. Yeah, it was like
people are like neat idea and they moved on to
other stuff. Um Beyond the study of color vision deficiency.
John Dalton of course continued to make important contributions to

(27:00):
the scientific world. Concurrently, while working on figuring out why
he couldn't see flowers the same way as other people,
he also published a work titled Meteorological Observation and Essays.
He published additional work in meteorology as well, and his
work in this field led to some fellow scientists considering
him the father of meteorology, although his work. Anytime somebody

(27:22):
gets called the father of something, I always have to
go because his work was of course building on that
of his mentors on this subject. He had particularly had
a really good mentor in meteorology when he was studying
as a teacher. Dalton also did a lot of work
in chemistry, specifically atomic theory. His work in this area
came to some incorrect conclusions, but it was also instrumental

(27:46):
in moving the scientific community away from the long held
idea that matter was at the basic level all the
same and just configured differently to form different things. Dalton
championed the idea that there were all kinds of different
atoms with different sizes and weights, and that they behaved differently.
He started a project to measure the masses of different

(28:08):
atomic particles to begin cataloging all of the different atoms
that could be found. He presented the first table of
atomic weights in eighteen o three, and his work in
this area propelled organic chemistry forward. He is also sometimes
called the Father of chemistry. Dalton had joined the Manchester
Literary and Philosophical Society in seventee when he was still

(28:30):
in his twenties. In eighteen seventeen, as a man in
his early fifties, he became its president. He held this
position for the rest of his life. His scientific career
slowed down quite a bit. Yeah, there were some other
issues where his He had some papers that were denied
for publication, and it just wasn't like the heyday he
had had when he was a little younger. He had

(28:52):
a unique distinction though, of seeing for example, his own
statue erected in Manchester during his lifetime for his accomplishments,
and while he had been barred from an education at
Oxford or Cambridge as a young man because he was
a Quaker not an Anglican, he received honorary degrees from
both later in life. He also served as a foreign
Associate of the French Academy of Sciences. On April eighteenth,

(29:15):
eighteen thirty seven, Dalton, who was seventy at the time,
had a stroke that resulted in a partial paralysis, and
then he had another small stroke or possibly a seizure
several days later. Being pretty pragmatic, he set his affairs
in order as soon as he was recovered enough to
do so. But then he lived another seven years. He

(29:36):
continued as president of the Literary and Philosophical Society. He
made visits to Lake Country. That's something that he had
been doing throughout his life. Yeah, it was a very
close call, and then he kind of was like, well,
I'm still alive. I'm gonna keep doing my living stuff. Uh.
John Dalton died finally on July forty four. He was

(29:56):
really really beloved in Manchester by this point, and he
was given a public funeral all by the city on
August twelfth, eighteen forty four, and estimated forty people paid
their respects before Dalton was interred. The day after Dalton's death,
on July eighteen forty four, his wishes were carried out
his eyes were dissected. This was done by Dr Joseph

(30:17):
Bransom to determine whether this idea about having a blue
humor in his eye was correct. Of course it was not.
Ransom described what he found in Dalton's eye as quote
perfectly pellucid and some also sliced off a section of
the posterior pole of the eye and used it as
a lens to see if colors that were viewed through it,

(30:39):
especially red and green, took on a different hue, which
they did not. But Dalton's eyes were not discarded after that,
so for clarity he did the full dissection on one eye.
That little part he sliced off was from the second eye,
um so he had only taken the primary samples from one.
The other was mostly intact, and the remains of Dalton's
eyes were preserved and were even actually given to the

(31:00):
Manchester Literary and Philosophical Society. That was not the end
of their story. A hundred years after Dalton died in
a DNA analysis was conducted on his preserved eyes, and
this examination determined that he had due to anopia, conclusively
proving that he had red green color vision deficiency. Two

(31:21):
years after those findings were published in seven the eyes
were donated to the Science and Industry Museum in Manchester
and they remain in the collection there to this day. Yeah,
you can find pictures of him online. Uh. In the
eighteen seventies, German anatomis Max Schultz identified the rods and
cones of the retina and deduced that rods were dedicated

(31:43):
to night vision and cones to daylight vision. Then later
in the eighteen seventies, Wilhelm kun laid the groundwork for
a concept of photochemical basis for vision. In the nineties,
Spanish neuroscientists Santiago Ramonica how studied the retina and drew
detailed diagrams of the cells within it. How scientific drawings

(32:04):
are incredibly intricate and very beautiful, and they were part
of an art exhibit at n y U. Yeah. So
you know, all of the things that would have explained
to Dalton what was going on came a little too late.
There was also a cool discovery so fairly recently, a
new kind of photo receptor was discovered, the ganglion cell,

(32:26):
and that once again refined our knowledge of how the
human eye takes in and processes visual information. Always learning. UM,
I really really really love John dalton story, and I
love this part of it. Um. I knew a little
bit more about you know, his work in in establishing

(32:49):
the basis of a lot of the chemistry we use,
but I didn't. I had never read this paper before,
and I honestly it's the most fun reading. It's very sweet.
I will switch gears completely form our listener mail though
okay one I won't read his mail because it's pretty short,

(33:12):
but I'll sum it up. I wanted to say hi
to Todd who wrote us he was listening to our
transfusion episodes while he donated platelets. So thank you Todd
for donating platelets. We have had several people right in
to make sure that we uh let people know that
donating blood is very important and it is. So this
is your p s A again and again, thank you Todd.
But my actual email that I'm gonna read is from

(33:34):
our listener, Larissa. I think that's probably how she pronounces it.
Who writes Hi, Holley and Tracy. I've been a fan
since sixteen and I always look forward to new episodes
each week. It helps keep my brain limber while at
home with the kids during lockdown, which we are currently
experiencing here in Ontario. Recently, I have been thrilled to
make connections between your podcast in my library. I just

(33:54):
finished reading Scherie Demelin's Empire of Wild, which is a
novel set within the Matti community of Georgian Bay, Canada,
in which a rugarou plays a major part. The moment
of the novel that answered the niggling part of my
brain that said, Ruguru, Where have I heard that before?
Was when one of the characters leaves thirteen objects on
her porch to protect herself because the rugarou can only

(34:15):
count to twelve. I'm so curious about how the creature
became part of both culture. Surely the link must be
the French. This may have set off the great rugaru
investigation of one on my part, invest which is yes,
we mentioned in that episode, although we didn't go super
deep because there's not really documentation of it that Since
Ruguru is kind of a shift from Lugaru, which is

(34:38):
French for werewolf, it seems to have traveled over with
French colonists, uh, and French fur trappers kind of became
pretty standard in in that area in the north and
then migrated south into Louisiana. That is the best guess
how it traveled since we don't have, like I said,

(34:59):
hard documentation him. But I love that the Rugaru and
his inability to count beyond a dozen is still delighting
people and making us all laugh because we need it
right now. Uh. If you would like to write to us,
you can do so at History podcast at iHeart radio
dot com. You can also find us as Missed in
History everywhere on social media. If you have not subscribed
to the show, why not, You can do it right now.

(35:20):
It's super easy, and you can do that on the
I heart Radio app, at Apple podcasts, or wherever you
listen to your favorite podcasts. Stuff you Missed in History
Class is a production of I heart Radio. For more
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