HOME

TheInfoList



OR:

Erethism, also known as erethismus mercurialis, mad hatter disease, or mad hatter syndrome, is a
neurological disorder A neurological disorder is any disorder of the nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakn ...
which affects the whole central nervous system, as well as a symptom complex, derived from
mercury poisoning Mercury poisoning is a type of metal poisoning due to exposure to mercury. Symptoms depend upon the type, dose, method, and duration of exposure. They may include muscle weakness, poor coordination, numbness in the hands and feet, skin rashes ...
. Erethism is characterized by behavioral changes such as irritability, low self-confidence, depression, apathy,
shyness Shyness (also called diffidence) is the feeling of apprehension, lack of comfort, or awkwardness especially when a person is around other people. This commonly occurs in new situations or with unfamiliar people; a shy person may simply opt ...
and timidity, and in some extreme cases with prolonged exposure to mercury vapors, by
delirium Delirium (also known as acute confusional state) is an organically caused decline from a previous baseline of mental function that develops over a short period of time, typically hours to days. Delirium is a syndrome encompassing disturbances ...
, personality changes and memory loss. People with erethism often have difficulty with social interactions. Associated physical problems may include a decrease in physical strength, headaches, general pain, and tremors, as well as an
irregular heartbeat Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults ...
. Mercury is an element that is found worldwide in soil, rocks, and water. People who get erethism are often exposed to mercury through their jobs. Some of the higher risk jobs that can lead to occupational exposure of workers to mercury are working in a
chlor-alkali The chloralkali process (also chlor-alkali and chlor alkali) is an industrial process for the electrolysis of sodium chloride (NaCl) solutions. It is the technology used to produce chlorine and sodium hydroxide (caustic soda), which are commodit ...
,
thermometer A thermometer is a device that measures temperature or a temperature gradient (the degree of hotness or coldness of an object). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb of a mercury-in-glass thermometer ...
,
glassblowing Glassblowing is a glassforming technique that involves inflating molten glass into a bubble (or parison) with the aid of a blowpipe (or blow tube). A person who blows glass is called a ''glassblower'', ''glassmith'', or ''gaffer''. A '' lampworke ...
, or
fluorescent light A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet ligh ...
bulb factory, and working in
construction Construction is a general term meaning the art and science to form objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009 and ...
,
dental clinic Dentistry, also known as dental medicine and oral medicine, is the branch of medicine focused on the teeth, gums, and mouth. It consists of the study, diagnosis, prevention, management, and treatment of diseases, disorders, and conditions of ...
s, or in
gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile ...
and
silver mines Silver mining is the extraction of silver from minerals, starting with mining. Because silver is often found in intimate combination with other metals, its extraction requires elaborate technologies. In 2008, ca.25,900 metric tons were consumed ...
. In factories, workers are exposed to mercury primarily through the base products and processes involved in making the final end consumer product. In dental clinics it is primarily through their interaction and installation of dental amalgams to treat dental
caries Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicati ...
. In the case of mining, mercury is used in the process to purify and completely extract the precious metals. Some elemental and chemical forms of mercury (vapor,
methylmercury Methylmercury (sometimes methyl mercury) is an organometallic cation with the formula . It is the simplest organomercury compound. Methylmercury is extremely toxic, and its derivatives are the major source of organic mercury for humans. It i ...
, inorganic mercury) are more toxic than other forms. The human
fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal dev ...
and medically compromised people (for example, patients with lung or kidney problems) are the most susceptible to the toxic effects of mercury. Mercury poisoning can also occur outside of occupational exposures including in the home. Inhalation of mercury vapor may stem from cultural and religious rituals where mercury is sprinkled on the floor of a home or car, burned in a candle, or mixed with perfume. Due to widespread use and popular concern, the risk of toxicity from dental amalgam has been exhaustively investigated. It has conclusively been shown to be safe although in 2020 the FDA issued new guidance for at-risk populations who should avoid mercury amalgam. Historically, this was common among old England felt-hatmakers who had long-term exposure to vapors from the mercury they used to stabilize the wool in a process called felting, where hair was cut from a pelt of an animal such as a rabbit. The industrial workers were exposed to the mercury vapors, giving rise to the expression "mad as a hatter". Some believe that the character
the Mad Hatter The Hatter is a fictional character in Lewis Carroll's 1865 book ''Alice's Adventures in Wonderland'' and its 1871 sequel ''Through the Looking-Glass''. He is very often referred to as the Mad Hatter, though this term was never used by Car ...
in
Lewis Carroll Charles Lutwidge Dodgson (; 27 January 1832 – 14 January 1898), better known by his pen name Lewis Carroll, was an English author, poet and mathematician. His most notable works are '' Alice's Adventures in Wonderland'' (1865) and its sequ ...
's ''
Alice in Wonderland ''Alice's Adventures in Wonderland'' (commonly ''Alice in Wonderland'') is an 1865 English novel by Lewis Carroll. It details the story of a young girl named Alice who falls through a rabbit hole into a fantasy world of anthropomorphic creatur ...
'' is an example of someone with erethism, but the origin of this account is unclear. The character was almost certainly based on Theophilus Carter, an eccentric furniture dealer who was well known to Carroll.


Signs and symptoms

Acute mercury exposure has given rise to psychotic reactions such as delirium, hallucinations, and suicidal tendency. Occupational exposure has resulted in erethism, with irritability, excitability, excessive shyness, and insomnia as the principal features of a broad-ranging functional disturbance. With continuing exposure, a fine tremor develops, initially involving the hands and later spreading to the eyelids, lips, and tongue, causing violent muscular spasms in the most severe cases. The tremor is reflected in the handwriting which has a characteristic appearance. In milder cases, erethism and tremor regress slowly over a period of years following removal from exposure. Decreased nerve conduction velocity in mercury-exposed workers has been demonstrated. Long-term, low-level exposure has been found to be associated with less pronounced symptoms of erethism, characterized by fatigue, irritability, loss of memory, vivid dreams, and depression (WHO, 1976). Effects of chronic occupational exposure to mercury, such as that commonly experienced by affected hatters, include mental confusion, emotional disturbances, and muscular weakness. Severe neurological damage and kidney damage can also occur. Signs and symptoms can include red fingers, red toes, red cheeks, sweating, loss of hearing, bleeding from the ears and mouth, loss of appendages such as teeth, hair, and nails, lack of coordination, poor memory, shyness, insomnia, nervousness, tremors, and dizziness. A survey of exposed U.S. hatters revealed predominantly neurological symptomatology, including intention tremor. After chronic exposure to the mercury vapours, hatters tended to develop characteristic psychological traits, such as pathological shyness and marked irritability (see box). Such manifestations among hatters prompted several popular names for erethism, including "mad hatter disease", "mad hatter syndrome", "hatter's shakes" and "
Danbury Danbury is a city in Fairfield County, Connecticut, United States, located approximately northeast of New York City. Danbury's population as of 2022 was 87,642. It is the seventh largest city in Connecticut. Danbury is nicknamed the "Hat City ...
shakes".


Biomarkers of exposure

While hatters in the past were diagnosed with erethism through their symptoms, it was sometimes harder to prove that erethism was the result of mercury exposure, as seen in the case of the hatters of New Jersey below. Today, although erethism from the hat making industry is no longer an issue, it persists in other high-risk occupations. As a result, methods have been established to measure the mercury exposure of workers more accurately. They include the collection and testing of mercury levels in blood, hair, nails, and urine. Most of these
biomarker In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, p ...
s have a shorter half-life for mercury (e.g. in blood the half-life is usually only around 2–4 days), which makes some of them better for testing acute, high doses of mercury exposure. However, mercury in urine has a much longer half-life (measured in weeks to months), and unlike the other biomarkers is more representative of the total body burden of inorganic and elemental mercury. This makes it the ideal biomarker for measuring occupational exposure to mercury because it is suitable to measuring low, chronic exposure, and specifically exposure to inorganic and elemental mercury (i.e. mercury vapor), which are the two types most likely to be encountered in a higher risk occupation.


History among hatters

Especially in the 19th century, inorganic mercury in the form of
mercuric nitrate Mercury(II) nitrate is an inorganic compound with the formula Hg(NO3)2.xH2O. These colorless or white soluble crystalline salts are occasionally used as a reagent. It is made by treating mercury with hot concentrated nitric acid. Neither anhyd ...
was commonly used in the production of
felt Felt is a textile material that is produced by matting, condensing and pressing fibers together. Felt can be made of natural fibers such as wool or animal fur, or from synthetic fibers such as petroleum-based acrylic or acrylonitrile or wood ...
for hats. During a process called carroting, in which furs from small animals such as rabbits, hares or beavers were separated from their skins and matted together, an orange-colored solution containing mercuric nitrate was used as a smoothing agent. The resulting felt was then repeatedly shaped into large cones, shrunk in boiling water and dried. In treated felts, a slow reaction released volatile free mercury. Hatters (or
milliner Hat-making or millinery is the design, manufacture and sale of hats and other headwear. A person engaged in this trade is called a milliner or hatter. Historically, milliners, typically women shopkeepers, produced or imported an inventory of ...
s) who came into contact with vapours from the impregnated felt often worked in confined areas. Use of mercury in hatmaking is thought to have been adopted by the
Huguenot The Huguenots ( , also , ) were a religious group of French Protestants who held to the Reformed, or Calvinist, tradition of Protestantism. The term, which may be derived from the name of a Swiss political leader, the Genevan burgomaster Be ...
s in 17th-century France, at a time when the dangers of mercury exposure were already known. This process was initially kept a
trade secret Trade secrets are a type of intellectual property that includes formulas, practices, processes, designs, instruments, patterns, or compilations of information that have inherent economic value because they are not generally known or readily ...
in France, where hatmaking rapidly became a hazardous occupation. At the end of the 17th century the Huguenots carried the secret to England, following the
revocation of the Edict of Nantes The Edict of Fontainebleau (22 October 1685) was an edict issued by French King Louis XIV and is also known as the Revocation of the Edict of Nantes. The Edict of Nantes (1598) had granted Huguenots the right to practice their religion without s ...
. During the
Victorian era In the history of the United Kingdom and the British Empire, the Victorian era was the period of Queen Victoria's reign, from 20 June 1837 until her death on 22 January 1901. The era followed the Georgian period and preceded the Edwa ...
the hatters' malaise became proverbial, as reflected in popular expressions like " mad as a hatter" (see
below Below may refer to: *Earth *Ground (disambiguation) *Soil *Floor *Bottom (disambiguation) *Less than *Temperatures below freezing *Hell or underworld People with the surname *Ernst von Below (1863–1955), German World War I general *Fred Below ( ...
) and "the hatters' shakes". The first description of symptoms of mercury poisoning among hatters appears to have been made in
St Petersburg Saint Petersburg ( rus, links=no, Санкт-Петербург, a=Ru-Sankt Peterburg Leningrad Petrograd Piter.ogg, r=Sankt-Peterburg, p=ˈsankt pʲɪtʲɪrˈburk), formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991), i ...
, Russia, in 1829. In the United States, a thorough occupational description of mercury poisoning among New Jersey hatters was published locally by Addison Freeman in 1860.
Adolph Kussmaul Adolph Kußmaul (german: Carl Philipp Adolf Konrad Kußmaul; 22 February 1822 – 28 May 1902) was a German physician and a leading clinician of his time. He was born as the son and grandson of physicians at Graben near Karlsruhe and studied at He ...
's definitive clinical description of mercury poisoning published in 1861 contained only passing references to hatmakers, including a case originally reported in 1845 of a 15-year-old Parisian girl, the severity of whose tremors following two years of carroting prompted opium treatment. In Britain, the toxicologist
Alfred Swaine Taylor Alfred Swaine Taylor (11 December 1806 in Northfleet, Kent – 27 May 1880 in London) was an English toxicologist and medical writer, who has been called the "father of British forensic medicine". He was also an early experimenter in photography ...
reported the disease in a hatmaker in 1864. In 1869, the
French Academy of Medicine French (french: français(e), link=no) may refer to: * Something of, from, or related to France ** French language, which originated in France, and its various dialects and accents ** French people, a nation and ethnic group identified with Franc ...
demonstrated the health hazards posed to hatmakers. Alternatives to mercury use in hatmaking became available by 1874. In the United States, a
hydrochloride In chemistry, a hydrochloride is an acid salt resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base (e.g. an amine). An alternative name is chlorhydrate, which comes from French. An archaic alternative n ...
-based process was patented in 1888 to obviate the use of mercury, but was ignored. In 1898, legislation was passed in France to protect hatmakers from the risks of mercury exposure. By the turn of the 20th century, mercury poisoning among British hatters had become a rarity. In the United States, the mercury-based process continued to be adopted until as late as 1941, when it was abandoned mainly due to the wartime need for the heavy metal in the manufacture of detonators. Thus, for much of the 20th century mercury poisoning remained common in the U.S. hatmaking industries, including those located in
Danbury, Connecticut Danbury is a city in Fairfield County, Connecticut, United States, located approximately northeast of New York City. Danbury's population as of 2022 was 87,642. It is the seventh largest city in Connecticut. Danbury is nicknamed the "Hat Cit ...
(giving rise to the expression the "Danbury shakes"). Another 20th-century cohort of affected hatmakers has been studied in
Tuscany it, Toscano (man) it, Toscana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Citizenship , demographics1_footnotes = , demographics1_title1 = Italian , demogra ...
, Italy.


Hatters of New Jersey

The experience of hatmakers in
New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delawa ...
is well documented and has been reviewed by Richard Wedeen. In 1860, at a time when the hatmaking industry in towns such as Newark, Orange and Bloomfield was growing rapidly, a physician from Orange called J. Addison Freeman published an article titled "Mercurial Disease Among Hatters" in the ''Transactions of the Medical Society of New Jersey''. This groundbreaking paper provided a clinical account of the effects of chronic mercury poisoning among the workforce, coupled with an occupational description of the use of mercuric nitrate during carroting and inhalation of mercury vapour later in the process (during finishing, forming and sizing). Freeman concluded that "A proper regard for the health of this class of citizens demands that mercury should not be used so extensively in the manufacture of hats, and that if its use is essential, that the hat finishers' room should be large, with a high ceiling, and well ventilated." (Cited in ) Freeman's call for prevention went unheeded. In 1878, an inspection of 25 firms around Newark conducted by Dr L. Dennis on behalf of the Essex County Medical Society revealed "mercurial disease" in 25% of 1,589 hatters. Dennis recognized that this prevalence figure was probably an underestimate, given the workers' fear of being fired if they admitted to being diseased. Although Dennis did recommend the use of fans in the workplace he attributed most of the hatters' health problems to excessive alcohol use (thus using the stigma of drunkenness in a mainly immigrant workforce to justify the unsanitary working conditions provided by employers). (Cited in ) Some voluntary reductions in mercury exposure were implemented after Lawrence T. Fell, a former
journeyman A journeyman, journeywoman, or journeyperson is a worker, skilled in a given building trade or craft, who has successfully completed an official apprenticeship qualification. Journeymen are considered competent and authorized to work in that fie ...
hatter from Orange who had become a successful manufacturer, was appointed Inspector of Factories in 1883. In the late nineteenth century, a pressing health issue among hatters was
tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, ...
. This deadly communicable disease was rife in the extremely unhygienic wet and steamy enclosed spaces in which the hatters were expected to work (in its annual report for 1889, the New Jersey Bureau of Labor and Industries expressed incredulity at the conditions—see box). Two-thirds of the recorded deaths of hatters in Newark and Orange between 1873 and 1876 were caused by pulmonary disease, most often in men under 30 years of age, and elevated death rates from tuberculosis persisted into the twentieth century. Consequently,
public health Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...
campaigns to prevent tuberculosis spreading from the hatters into the wider community tended to eclipse the issue of mercury poisoning. For instance, in 1886 J. W. Stickler, working on behalf of the New Jersey Board of Health, promoted prevention of tuberculosis among hatters, but deemed mercurialism "uncommon", despite having reported tremors in 15–50% of the workers he had surveyed. (Cited in ) (Cited in ) While hatters seemed to regard the shakes as an inevitable price to pay for their work rather than a readily preventable disease, their employers professed ignorance of the problem. In a 1901 survey of 11 employers of over a thousand hatters in Newark and Orange, the head of the Bureau of Statistics of New Jersey, William Stainsby, found a lack of awareness of any disease peculiar to hatters apart from tuberculosis and rheumatism (though one employer remarked that "work at the trade develops an inordinate craving for strong drink"). (Cited in ) By 1934 the U.S. Public Health Service estimated that 80% of American felt makers had mercurial tremors. Nevertheless,
trade union A trade union (labor union in American English), often simply referred to as a union, is an organization of workers intent on "maintaining or improving the conditions of their employment", ch. I such as attaining better wages and benefits ...
campaigns (led by the United States Hat Finishers Association, originally formed in 1854) never addressed the issue and, unlike in France, no relevant legislation was ever adopted in the United States. Instead, it seems to have been the need for mercury in the
war effort In politics and military planning, a war effort is a coordinated mobilization of society's resources—both industrial and human—towards the support of a military force. Depending on the militarization of the culture, the relative si ...
that eventually brought to an end the use of mercuric nitrate in U.S. hatmaking; in a meeting convened by the U.S. Public Health Service in 1941, the manufacturers voluntarily agreed to adopt a readily available alternative process using
hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3 ...
.


"Mad as a hatter"

Although the expression "mad as a hatter" was associated with the syndrome, the origin of the phrase is uncertain.
Lewis Carroll Charles Lutwidge Dodgson (; 27 January 1832 – 14 January 1898), better known by his pen name Lewis Carroll, was an English author, poet and mathematician. His most notable works are '' Alice's Adventures in Wonderland'' (1865) and its sequ ...
's iconic Mad Hatter character in ''
Alice's Adventures in Wonderland ''Alice's Adventures in Wonderland'' (commonly ''Alice in Wonderland'') is an 1865 English novel by Lewis Carroll. It details the story of a young girl named Alice who falls through a rabbit hole into a fantasy world of anthropomorphic creature ...
'' displays markedly eccentric behavior, which includes taking a bite out of a teacup. Carroll would have been familiar with the phenomenon of dementia among hatters, but the literary character is thought to be directly inspired by Theophilus Carter, an eccentric furniture dealer who did not show signs of mercury poisoning. The actor
Johnny Depp John Christopher Depp II (born June 9, 1963) is an American actor and musician. He is the recipient of List of awards and nominations received by Johnny Depp, multiple accolades, including a Golden Globe Award and a Screen Actors Guild Awa ...
has said of his portrayal of a carrot-orange haired Mad Hatter in
Tim Burton Timothy Walter Burton (born August 25, 1958) is an American filmmaker and animator. He is known for his gothic fantasy and horror films such as '' Beetlejuice'' (1988), '' Edward Scissorhands'' (1990), '' The Nightmare Before Christmas'' (1993 ...
's 2010 film, ''Alice in Wonderland'' that the character "was poisoned ... and it was coming out through his hair, through his fingernails and eyes".


See also

* Danbury Hatters' case *
Minamata disease Minamata disease is a neurological disease caused by severe mercury poisoning. Signs and symptoms include ataxia, numbness in the hands and feet, general muscle weakness, loss of peripheral vision, and damage to hearing and speech. In extreme ...


Notes


References


Sources

* {{Occupational safety and health Industrial hygiene Mercury (element) Mercury poisoning Neurological disorders Occupational diseases Shyness Occupational safety and health