Amalgámové plomby

06.10.2014 09:39
fuer angewandte Chemie, 29. Jahrgang, 15. April 1926, Nr. 15, S.
Gefaehrlichkeit des Quecksilberdampfes
von Alfred Stock (1926)

Dangerousness of Mercury Vapor

By Alfred Stock, Berlin-Dahlem
Kaiser-Wilhelm-Institut fuer
(Eingeg. Febr. 9, 1926)
Translated by Birgit Calhoun

When I am making the
decision to report without hesitation to a wider circle about my
personal problems, which ordinarily wouldn't concern others and would
not be worthy of publication, I am driven by the intense desire to
warn emphatically all those who have to deal with metallic mercury
about the dangers of this unstable metal, and to save them from the
horrible experiences which have spoiled a great part of my life.
Today I can speak about them freely because luckily they have been
concluded, and they are behind me with sufficient distance.

The insidious horror
of mercury is not nearly sufficiently well known and is being taken
note of too little in those places where one is particularly
threatened by it, in chemical and physical laboratories.

For nearly 25 years
I have suffered from ailments, which, in the beginning, arose only
occasionally, then gradually got worse and worse and finally
increased to unbearable proportions so that I disparingly doubted my
ability to continue to work scientifically. The cause was understood
neither by me nor many outstanding physicians. They thought that it
was possible that it could be found in the especially narrow built of
the nasal passages and an unusual irritability of the nasal mucosa.
Because of this, I underwent decades of treatments of the nose with
cauterizations, burnings, massages, electrification, and bloody
operations. Without success. Two years ago--a few of my colleagues
fell ill with similar symptoms--it was accidentally discovered that
it had to do with an insidious poisoning by mercury vapor. In my
chemical work, which involves testing of volatile substances by the
"vacuum method," which uses mercury-tubs, -pumps,
-manometers, and -valves
I had been in constant contact with mercury for 25 years.

Today there is no
doubt about the diagnosis any more because all my symptoms, although
not gone completely, have more or less been diminished
after having avoided inhaling mercury vapors for the last two years
without the use of any other healing methods.

First I am
describing the difficulties as they developed in me over time. They
are identical to an insidious mercury poisoning in every detail. I
was able to convince myself of this through my colleagues and other
peers, who suffered and still suffer from mercury vapor poisoning.
Some of them, it is noted, were not cognizant of the origin of their
difficulties. Many pertinent symptoms have, up to now, been
insufficiently described. At any rate, insidious mercury vapor
poisoning has not received the attention it deserves.

With me the
situation began with slight intermittent headaches and mild
drowsiness, which increased gradually, over the years, to constant
nervous restlessness and "jitteriness." Head-pressure
impaired the ability to think. It worsened and finally became an
almost uninterrupted vexing headache (sits mostly over the eyes). I
had strong vertigo, which was occasionally connected with visual
disturbances (unclear and double vision). Soon the upper air passages
were involved as well. This started with a slight transient nose
cold. This was followed by a constant "stuffy nose," which
later turned into severe nose, throat and sinus infections. They were
followed, one by one, almost without interruption, by pussy, often
bloody, mucosal discharge and scabbing, frequent sore throats and ear
aches connected to auditory loss and loss of smell (some sense of
smell remained; e.g. cyanic acid). There was a distaste for tobacco
smoke. During the last years prior to recognition of the poisoning,
there were added signs: a strong flow of saliva, a sour, insipid
taste in the mouth, infections of the eyes and oral mucosa. There
were little blisters, sensitive and sore areas on the tongue, the
palate, the gums and the insides of the lips and cheeks. There was
reddening of the gums and slight bleeding while brushing the teeth.
There were toothaches, receding of the gums and formation of
"pockets" and temporary loosening of individual teeth. The
mouth and tooth signs revealed themselves only (in part they only
reached their peak months after recognition of the poisoning)
because, since my youth, I have been taking good care of my teeth
(among other things nightly long rinses with 1 and 1/2% hydrogen
peroxyde solution and sodium bicarbonate). If this hadn't been the
case, I might possibly have become aware of the cause of my problems
through mouth infections.

Other signs were:
Mental weariness and exhaustion, lack of inclination and inability to
perform any, particularly mental, work, and increased need for sleep.
There were tremors of the spread-out fingers and also sometimes the
eyelids. There was pain in various locations of the body, tearing in
the back and limbs, and pressure in the liver area. At times, there
were disturbances of stomach and intestinal activity, loss of
appetite, sudden bladder pressure, isolated bouts of diarrhea, which
occurred without other possible causes. There were sudden blistery
rashes, e.g. on the insides of the arms and thighs.

The most depressing
accompanying sign relating to mental work was the diminshment of
memory. My memory, which had previously been excellent, left more and
more to be desired and became worse and worse until, two years ago, I
suffered from nearly complete memory loss.

Only with the help
of extensive notes and great effort was I able to put together a
scientific paper or deliver a lecture. I forgot the telephone number
on the way from the telephone book to the telephone. I forgot
everything that I had once learned by heart. I forgot the content of
the book or theater play I had just read or seen as well as my own
work, which had been published. It was impossible for me to remember
numbers and names. Often even the names of good acquaintances were
lost. Specifically, I lost the ability for arithmetic and
mathematical figuring. Also my chess playing ability suffered. The
impairment of memory, particularly that of people memory and the
worsening ability to do arithmetic, seem to be signs peculiar to
insidious mercury vapor poisoning. This showed itself in blatant form
in my co-workers and other people whom I got to know who had been
under the influence of mercury for a longer period of time. Soon
after all of us in the laboratory had found out what was wrong with
us, we sat down together to put down on paper a completed piece of
work where we had to do a lot of mathematics. None of us was able to
add up columns of ten to twenty multi-digit numbers without making

While my physical
ability, e.g. mountain climbing, did not seem to have been weakened,
the ability to work mentally suffered a little, although not in as
devastating a fashion as had been the case with memory. Added to that
were depression, and a vexing inner restlessness, which later also
caused restless sleep. By nature companionable and loving life, I
withdrew moodily into myself, shied away from the public, stayed away
from people and social activity, and unlearned the joy in art and
nature. Humor became rusty. Obstacles, which formerly I would have
overlooked smilingly (and am overlooking again today), seemed
insurmountable. Scientific work caused great effort. I forced myself
to go to the laboratory without being able to get anything useful
accomplished in spite of all efforts. Thought came laboriously and
pedantically. I had to deny myself working on solutions to questions
beyond the nearest tasks at hand. The lecture that used to be a
pleasure became a torture. The preparations for a lecture, the
writing of a dissertation, or merely a simple letter caused unending
effort in styling the material and wrestling with the language. Not
seldom did it happen that I misspelled words or left out letters. It
was not nice to be aware of these shortcomings, not to know their
cause, not to know a way to their elimination, and to have to fear
further deterioration.

All attempts to
improve the situation went awry. Staying in the mountains for many
weeks did not help. I felt hardly less ill than in Berlin. The nose
treatments and operations sometimes brought short-lived, yet never
lasting relief. It was peculiar that all mental difficulties
disappeared for hours when the physician treated certain areas of the
mucosa of the upper nose with cocaine. When the right spot was hit,
headache and vertigo disappeared sometimes in a few minutes; memory,
inclination to work, and good mood reappeared, but, sadly, only as
fleeting guests. Sometimes I made use of this possibility to call
them up before a lecture, an important meeting etc.

As already
indicated, my colleagues in the laboratory, my assistants, doctorants
[PhD Candidates], and female lab workers had already suffered for
some time from all kinds of problems: Fatigue without recognizable
cause, worsened memory, mild headaches and drowsiness, occasional
digestive disturbances, limb aches, slight mouth inflammation, nose
colds [runny nose], sinusitis etc. The difficulties expressed
themselves differently from person to person, whereby they came to
light foremost in the areas of lowest resistance. All of them showed
fatigue and diminished ability to perform mental tasks [work]. But
nobody had the idea that the cause of it could be the same for all of
us. Only the convergence of several lucky/unlucky circumstances
finally opened our eyes.

In 1921, out of
frugality, we had switched off the much more expensive power
consuming electrical ventilation system of the
Kaiser-Wilhelm-Institute for Chemistry. Since the middle of 1923, two
of my colleagues, an assistant and a Spanish guest, were working on
gas density measurements, which required maintaining a constant
temperature, and for this reason kept the windows and doors closed if
possible. The work had to be done by the spring of 1924 because my
assistant wanted to go into industry, and the Spanish colleague
wanted to return home. The work was performed hastily so that our
ordinarily scrupulous cleanliness suffered in every room. Spilled
mercury remained unattended, and much of it lay under tripods, in
cracks and slits between the floor boards and on tables. Thus the
conditions presented themselves that, instead of the slow insidious
mercury poisoning, the more easily recognizable acute mercury
poisoning became apparent. The assistant fell ill more seriously, not
only with headaches, mental fatigue etc., but also with stronger
bodily deterioration; with tooth abscesses and such. His brother, a
physician, suspected that the symptom complex pointed to mercury
poisoning. The experienced poison researcher L. Lewin [Louis Lewin,
1850-1929] whom we consulted checked out all laboratory personnel and
declared that, based on his experience, he was certain that all of us
were suffering from mercury poisoning. Indeed the test showed
(according to the procedure described in the following memorandum)
mercury in the air of the workrooms as well as in the urine of all
involved. The mercury content of the air in the individual rooms was
quite varied: Depending on the results of the specimens it showed
thousandth or hundredth of mg, i.e. only a small fraction of what the
air under saturation with mercury vapor can accomodate. At room
temperature, taking .001 mm mercury saturation pressure as its base
value, this figures to be about 12 mg per cubic meter. Since man
breathes in about 1/2 cubic meter air per hour, and the inhaled
mercury apparently
is retained for the most part in the lungs, it would require a very
extended period of time in mercury saturated air to suffer from acute
mercury poisoning. However it takes a long time after inhaling
mercury containing air before the poisoning becomes obvious. For one
or more years the signs may be limited to fatigue and slow
diminuition of mental performance and memory. Thus the already
mentioned Spanish colleague, for example, showed outward signs of
inflammation of the oral cavity only at the very end of the year he
stayed in our laboratory. The symptoms reached their climax months
after he had left us, and after he was removed from the influence of
mercury. He had noticed the mental effects much earlier without being
able to explain the cause. "For me, it was," he said, "as
if I was getting dumber and dumber in Germany." And I had to
make similar observations with my remaining co-workers. Thus all my
PhD candidates had difficulty withstanding the rigors of the doctor's
exams. The PhD candidates and assistants recovered after a few years,
once they had left the laboratory without being aware of the mercury
poisoning. As for me, the effects of the minute amounts of mercury
increased over the course of decades as described in the following

significant for insidious mercury poisoning is a noticeable coming
and going of symptoms. Following a few days or weeks of improved
well-being comes, sometimes setting in suddenly, a time of increased
ill health. This also happens in the form of frequent relapses during
the recovery period. As soon as my illness had reached its pinnacle,
there were, as a rule, one or two tolerable days. Then the saliva
flow, runny nose, and sinusitis, starting from the nose down to the
throat and sliding down to the bronchi, increased again. There were
tooth inflammations, highest fatigability and drowsiness, vexing
headache, often also tearing and diarrhea. Headache, drowsiness and
memory loss are connected to the irritation of the nerves leading to
the upper part of the nose seen in the already mentioned effect of
cocaine application on the nasal mucosa.

Apparently there are
many similarities between insidious mercury poisoning and the better
known lead poisoning. The [latter] is more thoroughly researched
because it happens more often in industry. It, too, concerns mainly
the nervous system and shows the same waxing and waning of the
symptom complex
"After a period of health the poison can suddenly, without
cause, display its effects again by evoking an attack of lead colic
or other symptoms. This phenomenon can only be explained by the
poison having been encapsulated for a long time in a place in the
body to which, suddenly, the circulation has access again..."
According to F. Schuetz and H. Bernhardt
lead deposits itself preferably in the spleen, gall bladder, and
brain, and is primarily excreted with the bile, possibly also through
the colon wall. The kidneys, in this case, are less involved in the
acute and chronic course of poisoning. Mercury seems to act
similarly. After one year of excluding mercury as the cause of
mercury poisoning, it could not be detected in my urine, in spite of
the fact that there were still very strong signs of illness. The
saliva, however, still contained mercury

After we had
recognized the source of our illness, our first worry was how to
protect ourselves from mercury in the future. The first thing, of
course, was to remove carefully everything on tables, in drawers,
slits, cracks and joints, and under damaged areas of the linoleum
flooring, whereby a modified "vacuum cleaner" (consisting
of suction connection, suction bottle with a long rubber hose in
front of which was attached a cut-burner type widened glass nozzle)
served us well. We had the linoleum repaired. All cracks in the work
tables were eliminated. The dangerous corners between floors and the
so-called scrub molding were rounded off (putty, painted with oil
paint) so that they were more easily accessible for cleaning.
Wherever tripods stood for a longer period of time, the joints
between tripod and table tops were also closed off with putty. All
open mercury surfaces on tubs, manometer holders etc. were covered as
completely as possible with fit-cut cellon plates. We avoided eating
in the work rooms or saving food and took especially good care
cleaning our hands (particularly brushing our finger nails) after
handling mercury. We also paid good attention so that no mercury fell
into pockets and folds of the work coats. Moreover we gave full
attention to the airing out of the work rooms by testing the success
with air analyses (Compare the following memorandum). It was soon
apparent that the reinstallation of the strong house ventilation
system (very strong ventilators in the attic suck the air out through
hoods; fresh air enters from channels through flaps above the doors)
was not nearly sufficient enough to make the air mercury free. The
situation in our laboratory is inopportune in that we are working
with particularly many mercury apparatuses whereby open mercury
surfaces and occasional sprinkling of mercury is not altogether
avoidable. An added factor is that the work rooms in the very modern
and well-built and furnished Kaiser-Wilhelm-Institut for Chemistry
are so large (several hundred cubic meters air space) that the air
does not get renewed fast enough by the ventilation system. In this
regard smaller rooms may be advantageous because, naturally, the same
ventilation works better and causes faster replacement of the air
Sufficiently airing ventilation, in this case, as it turned out, is
obtainable only through constantly opening windows and creating a
draft (regulated by temperature, windspeed, and -direction). At the
same time the ventilation system is at work. Because it rests at
night, the laboratory is being supplied with fesh air through opening
the windows wide. This measure is repeated at noon. Thus we have
succeded in keeping the laboratory air so clean that traces are
detectable only in small quantities, and we can continue working with
our mercury apparatuses without having to fear new health problems.

Whenever one deals
with mercury one should devote great care to the testing and
cleanliness of the air. One should check the airstream situation in
the work space
provide for as much fresh air as possible. It goes without saying
that all work with mercury, if at all possible, should be performed
under hoods
That is the only way that protects from damage with certainty. These
precautions are necessary even if one has to choose the path through
the Scylla of mercury poisoning and the Charybdis of a cold. A
chemical removal of mercury cannot be obtained according to our
experiences. It had been suggested to distribute sulfur powder or
zinc dust in the work place. We also tried large foil flags that were
hung in long rows from the ceiling. Although tin foil amalgamates
quickly if you put it into a closed container next to mercury, it
failed in this case: The mercury content in the air did not lessen
noticeably; one tin flag (33 X 100cm area; weighing 57g), which had
hung for 11 months over a mercury apparatus, was weighed afterwards.
It contained only .005 mg mercury.

The recovery from
insidious mercury poisoning, after the removal of the poison source,
takes place very slowly. Professor Lewin predicted this, and the
development of our wellbeing confirmed this. The time period is
visibly connected to the duration of the poisoning, and possibly also
to how old you are. My co-workers who had left the laboratory were,
thankfully, rid of their problems in the course of 1 - 2 years and
have fully recovered the freshness of their thinking ability and
memory. Nevertheless, even they had to suffer for a long time from
relapses not only of mental but also of physical nature (particularly
mouth inflammation). Some assistants and female lab workers continued
to work here where they, unfortunately, cannot operate without
mercury. Even today, after two years, they are still suffering from
clearly visible, but steadily diminishing, after-effects of the
poisoning. As for me, who was exposed to the damaging influences for
over 20 years, the recovery apparently is taking the longest. All in
all, I recovered the ability to work. I had only occasional relapses
(headaches, drowsiness and mild mouth inflammation). Considering the
course of the recovery up to now, I do not doubt, however, that my
last co-workers and I will lose our symptoms completely. It seems
that you have to count on it to take years to excrete the mercury
again that took years to build up in the body. In this regard the
following case has been educational to me recently, which at the same
time proves that it is irrelevant for the course of insidious mercury
poisoning whether the poison gets into the body via the lungs or
through the skin

A medical assistant
who had applied mercury salve therapy on his patients fell ill in
1905 with those symptoms (moodiness, headache, vertigo), which
gradually got worse (fatigue, unbearable headache, oral inflammation,
loosening and loss of teeth, constant runny nose, sinusitis, sore
throat, ringing in the ears, hearing and vision disturbances). Only
in 1911 was the situation recognized as mercury poisoning. The man
stopped applying the salve therapy, but still needed many years
before he lost his symptoms. After 1914, when he went to war he
suffered from headaches and drowsiness. Today as a
fifty-five-year-old he is again the picture of health and quite

It seems that an
existing mercury intoxication preconditions a special sensitivity
vis-a-vis renewed exposure from mercury vapor. Some of us who, at our
work, and also during occasional mistakes with ventilation, had come
in contact again with more mercury, noticed this soon because of the
stronger symptomatology after the relapses. That is not surprising
because, as the long development period of the insidious illness
shows, a certain borderline value has to be reached before noticeable
symptoms appear. The borderline value is certainly exceded for a long
time, even during recovery, so that each added amount of mercury
worsens your wellbeing at once.

On doctor's orders
we tried to hasten the recovery in various ways through use of
diuretics and emetics, through hot baths and prolonged use of small
amounts of sodium iodide. I do not get the impression that healing
was particularly accelerated. The iodide has the reputation of
bringing the metal into soluble form from insoluble organic mercury
compounds. This is the form in which the mercury is probably anchored
in the body. As far as I am concerned, there was no proof that
significantly more mercury was excreted after addition of iodide. No
progress was to be expected from diuretics, as already mentioned,
since the mercury excretion in the urine had stopped relatively soon
altogether. The healing arts are sadly lacking in medicines that
detoxify mercury in the body

Exercize in fresh
air is still best suited to make the subjective symptoms less
noticeable. With milder headaches and vertigo Novalgin has been
proven worthwhile as a palliative. All in all, it has to be left to
time to become master over this destroyer of peace. For me even a
four-week long stay in the high mountains and an ocean voyage to
southerly latitudes brought hardly any progress, (which normally
occurs with unaffected people), although, naturally, the mental
relaxation helped the nerves.

Why were our
illnesses not recognized sooner as being mercury poisoning? I have
often asked myself this question, not without self-accusations. The
first signs, those that preceded the oral signs of slow mercury
poisoning, are hardly known by the medical profession.
They consist only of fatigue, lowering of thinking and memory skills,
slight headaches and drowsiness and rare occasional diarrhea. In the
same way, it was little known until now that the nose and remaining
breathing passages are being compromised in the form of a runny nose
and sinusitis. But exactly these symptoms brought me and the
physicians who treated me on the wrong track, and have been
misleading in other cases that I have come to know about. Thus one of
my assistants was treated for a long time for a sinus infection
before the true cause came to light. By the way, balanced judgment of
the bad situation becomes impaired in those who are affected exactly
because of the existing drowsiness: "Quem Mercurius perdere
vult, dementat prius!" [Whom Mercury wants to destroy, he first
robs of his mind!]

At this time I would
like to warn about a little known source of insidious mercury
poisoning: It is amalgam tooth fillings. Professor Lewin suggested to
me at once, when he noticed mercury poisoning in me, to replace all
amalgam fillings--of which I had a considerable number in my mouth
since early youth--with other fillings. Telling me this, he recalled
a case of a university colleague who was at the edge of mental and
physical collapse when the cause was found just in time. It was found
in the numerous amalgam fillings stemming from the time when he was
young. After their removal slow recovery followed.

Dentists used to
prefer copper and cadmium amalgams and now often use the so-called
silver amalgams for tooth fillings because these amalgams are easy to
work with and fill out the cavities well. Silver amalgam is superior
to the earlier named amalgams, which corode and rot over time.
However it, too, releases mercury at room temperature as the
following assays
proved to us:

We enclosed silver
amalgam samples in an evacuated glass tube, which was bent [in the
middle] at a ninety-degree angle with the ends melted shut. The
horizontal tube shank with the amalgam piece was kept warm at 30-35
degrees C; the other shank serving as a recepticle, was cooled with
ice or liquid air. We then measured the mercury that had sublimated
in the receptacle in all cases.

  • I. Amalgam piece
    carefully made for this purpose by dentist in the state-of-the-art
    method from metal powder and mercury: .801 g. Enclosed by melting
    into glass tube 24 hours after manufacture. Warmed [30-35 degrees]
    for 23 days. Receptacle in ice. Distilled mercury = 11.2 mg

  • II. Same as above:
    .810 g. Kept for three weeks to make hardening as complete as
    possible. Only after that period of time was it enclosed by melting
    into glass tube. Warmed [30-35 degrees] for 12 days. Receptacle in
    liquid air. Distilled mercury = 15.3 mg

  • III. Amalgam piece
    made by taking care using as little mercury as possible: 1.000 g. As
    in II. was kept in the open for three weeks. Warmed [30-35 degrees]
    for 9 days. Receptacle in ice. Distilled mercury = 8.2 mg

  • IV. Amalgam
    filling, which had been in a tooth for years and had fallen out:
    .894 g. Warmed [30-35 degrees] for 14 days. Receptacle in liquid
    air. Distilled mercury = 29.4 mg

Without doubt, the
fillings that were used here in the laboratory would have allowed
mercury to evaporate from the mouth as well and supplied the inhaled
air with a small amount of mercury, which, in the long run, has to be
harmful. The old copper and cadmium amalgams are likely to be even
more harmful.

For some time, one
of my faculty colleagues had been suffering from occasional headaches
and drowsiness the cause of which he couldn't explain. After he had
an old amalgam filling removed, which had caused a slight infection
near the tooth in question, his symptoms disappeared gradually. After
its removal the filling showed itself as crumbly and laced with
mercury droplets, throughout.

Dental medicine
should do without the application of amalgam as means for filling
teeth altogether or, at least, wherever at all possible. There is no
doubt that many complaints such as fatigue, memory weakness, oral
inflammation, diarrhea, lack of appetite, chronic runny nose and
sinusitis are sometimes caused by mercury that has been directed to
the body from amalgam fillings, maybe only in small quantities, but
constantly. The physicians should give this fact the most serious
attention. Then it will probably become apparent that the frivolous
introduction of amalgams as tooth filling device was a nasty sin
against humanity.

Insidious mercury
poisonings are certainly much more common than ordinarily thought.
This is true particularly for chemists and physicists who so often
have to work with it. The great danger here is being noted much too
little, and the true cause of symptoms and illness is often not
recognized. In literature you find almost nothing about this.
Since the discovery of our misfortune I have found out about a dozen
certain cases of insidious mercury poisoning, just in the circle of
my acquaintances. They almost always have the same symptoms. Often
the correct cause was missed and therefore the correct treatment was
missed as well. An important example is that of a foreign colleague
who had been working with mercury apparatus' for a long time. When he
visited me and I asked him whether he had ever felt any mercury
poisoning, he decidedly said that he had not. Upon further
questioning about his health he then admitted: "I am in bad
shape. For years I have been suffering from neurasthenia and had to
stay away from the laboratory from time to time." The doctors
had tried all kinds of things with him. They had treated him for
stomach, intestinal, and ribcage disease with a special diet etc. In
reality what he had been dealing with was full-blown mercury
poisoning without doubt.

One unknowing victim
of mercury poisoning has probably been Faraday. In the last two to
three decades of his life, which came to an end in his late
seventies, he was bothered increasingly by health problems, which
made his scientific work more and more difficult, and which played a
significant role in his letters and descriptions of his life. They
were diagnosed by physicians as neurasthenia and early onset
arteriosclerosis. They consisted of, at times, strong mental and
physical fatigue, "irritable weakness," headaches, vertigo,
"rheumatism" and, more than anything else, constant
increasing memory loss.

Faraday, being
spared serious "bodily" illnesses, was even in old age a
strong hiker and swimmer. But he avoided people for the last third of
his life. Scientific work, including his lectures, were continued
with long interruptions into the last decade of his life. It is heart
rending to read in the great researcher's letters that he went to see
his physician friend so often to complain to him about vertigo and
headache, that he couldn't remember names, that he was losing the
connections with his colleagues, that he was forgetting his own work
and notes, that he was forgetting his letter writing, and that he
didn't know any more how to write words. "The affected organ is
my head. The result is loss of memory and clarity and vertigo."
All these symptoms make it most likely that Faraday suffered from an
insidious mercury poisoning from the vapors used in the laboratory.
It makes you shudder to think how, in all likelihood, this rich
intellect could have been freed from this suffering, and what gifts
he could have given to science if the cause of his illness could have
been recognized and remedied.

Jaensch (Marburg) brings this to my attention--the mysterious
sickness the mathematician, physicist, and philosopher, Blaise Pascal
(1623-1661), succumbed to when he was still young was mercury
poisoning. Pascal worked with mercury in his well-known barometer
research. His suffering from sustained headaches, vertigo, toothache,
loss of appetite, and lasting bad colic complete the picture of
advanced slow mercury poisoning.

No doubt mercury,
the use of which sadly cannot be done away with in research, has done
heavy damage to science in the past as it still does today in the way
it curtailed the output of many a researcher. May this present-day
warning help us pay better attention and avoid the dangers of this
insidious metal.

view the bibliography in the original article:
Gefaehrlichkeit des Quecksilberdampfes, von Alfred Stock (1926)