That’s…sort of a weird reason to ask? But okay, whatever.
Green eyes are a lot like blue or grey eyes - the color doesn’t come from simple pigmentation of the iris, like it does in brown eyes.
Green eyes come from a light brown or amber pigmentation of the iris stroma (right underneath the iris pigmentary layer), combined with the blue tone imparted by the Rayleigh effect (i.e. the elastic polarization of photons, and why the sky is blue).
So there’s no true “green” involved, just light brown/dark yellow or amber pigmentation combined with scattered light above it.
In Iceland, 87% of people have either blue or green eyes, and in European Americans, about 16% of people recent (within 2 generations) German or Irish ancestry have strongly green eyes. It’s also present in most other European and Central Asian genotypes, though not as common.
My cats also have green eyes.
Look at my cats.
Cats cats cats.
An eponym is a word derived from the name of a person, real or fictional. They can be found in every discipline of academia, but are particularly prevalent in medicine and physiology.
There are signs, reflexes, diseases, syndromes, medical instruments, and almost everything else you can think of, named after the discoverer, inventor, or someone else significant in the term’s development. Often the names become so associated with what they refer to that the historical figure is completely forgotten, even among those who use the term every day.
In light of that, let’s check out a few of the real people who have their legacy preserved in the parts of the body associated with their name -
Anatomical Eponyms -
Eustachian tube: Named after Bartolomeo Eustachi, a 16th-century Italian anatomist. Though very little is known about his life in general, he was physician to nobility and religious figures, and was unusually open (for the age) to new “innovative” ideas about anatomy not put forth by Galen, something his contemporaries actively fought. The Eustachian tube is a 3-4 cm canal that connects the middle ear to the nose, which maintains equal atmospheric pressure on either side of the eardrum. Admirer of Eustachi Antonio Maria Valsalva first coined the term “Eustachian tube” around 100 years after Eustachi’s death.
Fallopian tubes: Named after Gabriele Falloppio, one of the most important anatomists of the 16th century, and a contemporary of other notables such as Eustachi and Vesalius. He corrected many of Vesalius’ mistakes in myology, and wrote some of the most detailed works on the inner ear and sexual organs to date. The Fallopian tubes are two fine ciliated tubules in females, leading from the ovaries to the uterus, which carry mature ova away from the ovary during ovulation.
Organ of Corti: Named after Alfonso Giacomo Gaspare Corti, an Italian anatomist who performed some of the first microscopic studies on mammalian hearing in the mid-19th century. His methods of preserving the cochlea were able to effectively allow him to discover some of the tiny mechanisms of hearing that hadn’t been previously understood. The organ of Corti is the organ in the inner ear that has the auditory sensory cells, or “hair cells” - those things your doctor warns you can’t re-grow if you listen to music too loudly!
Cowper’s Glands: Named after William Cowper, the late-17th-century English anatomist, who was the first to describe these glands. Though considered a great surgeon and anatomist in his own right, there was an unfortunate incident where he published several plates of Govard Bidloo’s musculature works under his own name (with no mention of Bidloo), and there was a very heated exchange between the two men and their supporters. The Cowper’s glands are small glands in the male, on either side of the prostate gland, and release pre-seminal fluid. This fluid neutralizes the acidic traces of urine in the urethra, which has the potential to kill the spermatozoa.
Haversian Canal: Named after 17th-century (I sense a bit of a trend here…) English anatomist Clopton Havers. He was a physician with a keen interest in microscopy and bones, and was the first to document several unique substructures in both compact and spongy bone. The Haversian canals are small hollow canals that run within the longitudinal axis of compact bones, which generally contain one or two capillaries and a nerve. They deliver nutrients to the living bone cells.
Bundle of His: Named after Wilhelm His Jr., the late-19th-century Swiss cardiologist and anatomist. He practiced and taught medicine in Berlin, Germany, and only became a cardiologist later in life. His earlier work on diseases led to his name being used as one of the eponyms for trench fever, which is a pretty horrendous disease of war. The bundle of His is also known as the atrioventricular (AV) bundle, and is a collection of cardiac muscle cells specialized for electrical conduction, essential for a rhythmic heartbeat.
Islets of Langerhans: Named after Paul Langerhans, a 19th-century German physiologist, pathologist, and biologist. He was the son of a physician and was keenly interested in anatomy from an early age, and many of his most important discoveries were before he turned 30. He was also keen on biology, and did work on the fauna of Syria and the surrounding areas. The islets of Langerhans are the regions of the pancreas that contain the endocrine cells. They’re most well-known for producing insulin.
Circle of Willis: Named after Thomas Willis, a 17th-century English physician and founding member of the Royal Society of London. He also belonged to the circles that the many notable contemporary Oxford scientists comprised. Though he had a very well-off medical practice, his association with the Oxford experimenters led to significant time spent in the dissection room and trading ideas. Willis wrote about rudimentary psychological principles, neurology, and the anatomy of the brain. The Circle of Willis is a circle of arteries at the base of the brain. It creates a level of redundancy for the brain’s blood supply, meaning that if one part of it gets blocked or narrowed, the brain can stay fully oxygenated by getting blood from another artery that connects to the Circle.
Of course, this is only a few of the many medical and anatomical eponyms out there, but they’re some of the ones you tend to hear about a lot but might not know the origin of.
Next time I’ll cover Purkinje fibers, the Node of Ranvier, the Loop of Henle, Malpighian bodies, Meissner's corpuscles, Volkmann’s canals, Sharpey’s fibers, and Herring bodies (which are not fish).
Sources and Further Reading:
The origins of medical terms are interesting enough, but Greek and Latin roots are used throughout the sciences, and around here, you’ll see them a lot when it comes to species names. There are some interesting ones out there, with some bizarre (and sometimes humorous) meanings…
But first! Some taxonomy basics:
Setting aside phylogeny-specific nomenclature and cladistics for now, Linnaean taxonomy is the system of naming species that has been used since, well, Carl Linnaeus. A “taxon" (plural taxa) is simply a grouping of one or more organisms, judged to belong to the same unit based on any number of qualifications.
Though current “Linnaean taxonomy" (which is what’s commonly used in schools and in general literature) differs significantly from Linnaeus’ original three-kingdom, five-level, ranked classifications, it’s still known by that name and takes many of the concepts from it, such as hierarchical classification. Thanks to the popularity of Linnaeus’ 1735 work, Systema Naturae, a solid foundation for modern taxonomy was put in place, with an organized system, and short, understandable, scientific names.
Currently, animal species are organized according to rules set down by the International Code of Zoological Nomenclature, to ensure uniformity across the zoological community. Plants and bacteria follow different naming codes, but those are less relevant here.
This is a basic schematic demonstrating the hierarchical system that’s used when we classify a species:
According to the ICZN, the basic rank is that of species. The next most important rank is that of genus: when an organism is given a species name it is assigned to a genus, and the genus name is part of the species name. Species and genus were both seen by Linnaeus as “God-given”/”natural”. Anything above genus was considered a construct made by man to more easily classify the world around him.
The third-most important rank, although it was not used by Linnaeus, is that of family. Even though family is important in understanding the classification of an animal, it is not used in the “scientific name”, nor are any of the higher levels in its classification.
So what’s a “scientific name?”
The italicized names that you see in scientific literature (and around here) refer to the specific species of a creature, and are called the binomen; that is, “two names”. Those two names are the genus (first, and capitalized) and the species (second, never capitalized, even when named after a proper noun). An example of a binomen would be Choloepus hoffmanni - the genus is Choloepus, the two-toed sloths, and the species is Choloepus hoffmanni, Hoffmann’s two-toed sloth.
Sometimes there are three names, or the trinomen of a creature. These tell you, first, the genus, second, the species, and third, the subspecies. Take the trinomen Choloepus hoffmanni pallescens. The genus is Choloepus, the species is Choloepus hoffmanni, and the subspecies is Choloepus hoffmanni pallescens, the Peruvian two-toed sloth.
Though you only are told the two (or three) most specific taxonomic groupings for a creature, you can use those (and a phylogenetic tree) to figure out all of the less-specific (Linnaean) taxa it belongs to, such as its Family, Order, Class, and Phylum.
What does the scientific name actually mean, though?
Often, the scientific name describes notable or distinguishing characteristics about a species, that you can decode (scientific terminology time!). Let’s take the species Cyclopes didactylus. The first name given tells us that this creature belongs to the genus Cyclopes - “Circle-foot”. Within that genus, the species name is Cyclopes didactylus (abbreviated C. didactylus after the first use), and yes, you do repeat the genus name in the species name, by ICZN guidelines. On its own, “didactylus" can be broken down to the roots of di-, dactyl, -(o)us. “Having two fingers.” So the binominal can be deciphered as “Circle-foot having two fingers.”
Circle-foot two-fingers! (aka the Silky or Pygmy Anteater)
This descriptive-type species name is not the only way scientists assign taxa, though.
For everything above genus, the taxa are fairly regulated/already-determined, are not easy to add and subtract from, and have strict naming guidelines. From genus on down, though, so long as what you’ve discovered is verified as a new species (or group of species falling together as a genus), congratulations! You have the honor of naming it. Well, assuming it’s not patently offensive, vulgar, or unpronounceable. The ICZN approval board or the equivalent for your field has final say on whether or not a species can be given a submitted name.
Still, there are many ways to name a new species. You can name it in reference to physical characteristics, location found, a specific person or group, or even an ironic joke or pun. Look at the name Linnaeus gave the Blue Whale:
Balaenoptera musculis. Balaenoptera = “Baleen-winged”, ok, they have huge fins and baleen, so that makes sense. Musculis = "little mouse". Har har har.
“Musculis" can also refer to "muscle," but given that Linnaeus was given to puns and double-meanings, he was well aware of the "little mouse" definition.
**Though the specific epithet for a species can be used in more than one genus, genus names must remain absolutely unique, in accordance with ICZN rules. Ex. Since you can have more than one species with the didactylus epithet, Cyclopes didactylus and Inimicus didactylus are both valid names - though you really don’t want to mix up the silky anteater with the "devil stinger"/lumpfish.
**When the specific species is not known, the abbreviation “sp.” is used after the genus name. Ex. Lutra sp. refers to either Lutra lutra OR Lutra sumatrana, but it’s unknown as to which one. When multiple species within a genus are being referred to (or the specific species is unimportant), the abbreviation “spp.” is used after the genus name. Ex. Lutra spp. refers to BOTH Lutra lutra AND Lutra sumatrana.
-one modern bathtub holds approximately 80 gallons of water when completely full
-a human displaces one gallon of water for every ~8.3 lbs of weight at 4 C/39.2 F
-at 150 lbs, one human would displace ~18 gallons
-assuming you don’t want to cause the tub to overflow but to be near the top, you need about 60 gallons of liquid
-one human contains ~5 quarts of blood (1.25 gallons)
Assuming full exsanguination (optimistic, I know), you would need 48 humans in order to bathe in blood.
You’d probably want 50, just to be certain you have enough blood. Up that amount to 75 or so if you’re looking to bathe in the blood of virgins or you have one of those old-style claw tubs.
I TEACH YOU ALL VALUABLE LESSONS
Báthory Erzsébet (the Countess of Bathory) tortured and exsanguinated between 200 and 650 girls and young women between the years of 1585 and 1610, in an effort to preserve her youth, with virginal blood.
- Bald’s Leechbook, Vol. III : ca. 850 C.E.
Retrieved from Extra-Medical Elements in Anglo-Saxon Medicine, by Audrey L. Meaney, in the Social History of Medicine, Vol. 24 No. 1.