The History of Iodine
The discovery of iodine, like most discoveries, was a fortuitous
accident. The most fortuitous accident in the history of medicine, is
one story many of us are familiar with: the discovery of penicillin.
We've all heard the stories of the mold ruining the cultures and how
suddenly, a mind shift occurred and bingo, the birth of antibiotics. Few
realize that penicillin had been discovered a lot earlier, back in the
late 1800's by a medical student. But, sadly, the world wasn't ready for
it and, the haughtiness of physicians at that time would not allow them
to look upon a mere student's discovery with more than condescending
curiosity. Even fewer are aware that Pasteur discovered and wrote up the
first antibiotic experiment, in which he watched a substance gobble up
his bacteria specimens. That "substance" was garlic.
In 1811 when Bernard Courtois (1777-1838) discovered
iodine, he was not searching for a way to heal his fellow humans. On the
contrary; he was looking for a way to kill his fellow humans.
Napoleon's army at the time required huge quantities of gunpowder and
supplies were running short. Saltpeter (potassium nitrate—KNO3—sometimes
spelled saltpeter) is a major component in gunpowder and requires an
abundant source of sodium carbonate to be manufactured. Sodium carbonate
is extracted from wood ashes, but the war had gone on so long that
they'd run out of willow wood, the preferred source. Someone suggested
using dried seaweed (burnt to ash), which seemed to be abundant off the
coasts of Normandy and Brittany. The suggestion worked and the French
were back in business, making gunpowder and killing people.
However, in the process of making saltpeter, excess
sulfur compounds were created and they had to add sulfuric acid to the
mixture to get rid of them. Courtois accidentally added a bit too much
acid one day, and poof, a violet vapor cloud appeared and condensed onto
the colder, metal objects and formed lustrous crystals. Courtois, a
working chemist, realized he'd created something new. He performed a few
minor experiments with this new substance and noted that it combined
well with phosphorous, hydrogen, and a few metals, but did not combine
easily with oxygen or carbon. Furthermore, he discovered that it was
quite explosive when mixed with ammonia and did not decompose when
He suspected he'd discovered a new element, but the war
(Napoleon having stretched the government's coffers to the point of
bankruptcy) was the focus of France's spending at the time, and without
funding, he could experiment no further. Besides, there was a war to
fight. So he turned his discovery over to the French chemist (and
physicist) Charles-Bernard Désormes (1777-1862), who, with the help of
his son-in-law Nicolas Clément (1779-1841) performed the scientific
investigation into this new element.
Courtous, for some reason, also gave samples to Louis-Joseph Gay-Lussac (1778-1850) and André M. Ampère (1775–1836).
Both teams went to work investigating this new
substance and in November of 1813, at a meeting of the Imperial
Institute of France, Désormes and Clément announced their discovery. A
few days later Gay-Lussac and André M. Ampère published that this was
either an element or a compound of oxygen. No one yet, knew for sure
exactly what it was, until the English chemist Sir Humphry Davy got into
the picture and did some experiments with samples given him by Ampère.
Davy published, on the 10th of December, 1813, a little
piece in which he described this substance's qualities as being similar
to chlorine, and that it was quite analogous to both Fluorine and
Chlorine. He named it Iodine from a Greek word for "violet colored" but
the hubbub did not stop there. Suddenly the priority rights over the
substance were in dispute (who did what first and so on) while both
Gay-Lussac and Davy acknowledged that Courtois was the discoverer.
Later, Jean Lugol discovered that bonding iodine to a
mineral (potassium) made it water soluble, and allowed for the later
discovery of iodine's antiseptic qualities. Iodine naturally dissolves
in alcohol, but not in water until it is first bonded to the elements
potassium or chlorine.
The use of antiseptics, the general use of antiseptics
and acceptance of the theory of germs, was far off. Iodine made it's
leap into medical history when a Swiss physician, Dr Jean François
Condet announced that iodine could reduce goiters (enlarged thyroids).
At this moment, modern medical science is born. For the
first time in history we have a specific disorder that is relieved by a
specific treatment, which was discovered through empirical reasoning
(experimentation based upon trial and error).
Linus Paulding's Research on Iodine
Iodine is an essential component of the thyroid hormones,
triiodothyronine (T3) and thyroxine (T4), and is therefore essential for
normal thyroid function. To meet the body's demand for thyroid
hormones, the thyroid gland traps iodine from the blood and incorporates
it into thyroid hormones that are stored and released into the
circulation when needed. In target tissues, such as the liver and the
brain, T3, the physiologically active thyroid hormone, can bind to
thyroid receptors in the nuclei of cells and regulate gene expression.
In target tissues, T4, the most abundant circulating thyroid hormone,
can be converted to T3 by selenium-containing enzymes known as
deiodinases. In this manner, thyroid hormones regulate a number of
physiologic processes, including growth, development, metabolism, and
The regulation of thyroid function is a complex process that involves
the brain (hypothalamus) and pituitary gland. In response to
thyrotropin-releasing hormone (TRH) secretion by the hypothalamus, the
pituitary gland secretes thyroid-stimulating hormone (TSH), which
stimulates iodine trapping, thyroid hormone synthesis, and release of T3
and T4 by the thyroid gland. The presence of adequate circulating T4
and T3 feeds back at the level of both the hypothalamus and pituitary,
decreasing TRH and TSH production (diagram). When circulating T4 levels
decrease, the pituitary increases its secretion of TSH, resulting in
increased iodine trapping as well as increased production and release of
both T3 and T4. Iodine deficiency results in inadequate production of
T4. In response to decreased blood levels of T4, the pituitary gland
increases its output of TSH. Persistently elevated TSH levels may lead