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The element thallium
is not as well known as arsenic but it
is very, very toxic.
It also used to be very widely available
because it used to be the standard rat
poison,
and in some countries around the world,
you can
still buy thallium compounds to use as rat
poisoning.
And you can see from this picture,
it says, "Thallium, rough on rats".
Well, it's not just rough on rats,
it's also very rough on people.
The lethal dose is about 12 milligrams per
kilogram body weight.
And it works by interfering with the
nervous system,
and this is due to a chemical similarity
with the element potassium.
Unlike arsenic, however, thallium has a
particular symptom that is very, very
characteristic.
And that is, if you're poisoned with
thallium,
one of the things that will happen is that
all of your hair will fall out.
This is very characteristic of thallium.
One poisoner who used thallium was Graham
Young, a very disturbed individual.
Graham started his career of poisoning
even at the age of 14, when he murdered
his stepmother.
He was sent not to prison, but to
Broadmoor Psychiatric Hospital.
This is a secure hospital and the people
there are treated as well as detained.
There are rumours that he may have poisoned
another inmate while he was in Broadmoor,
but in 1971, he was considered to be cured
and so he was released back into the
community.
When he was released, he was able to get a
job and he got a job working in a
warehouse.
By an unfortunate coincidence, one of the
duties that
he had in this warehouse was to make the
tea.
So it's the perfect job for a would-be
poisoner.
So, it's believed that he attempted to
poison eight of his co-workers
using either thallium or antimony.
Now, Graham Young doesn't seem to have
been interested
in killing a lot of people as fast as
possible, because he would give relatively
low doses for
a long time so he could watch the effects
and then, presumably, give a higher dose
later.
The result was that while eight of his
co-workers became ill, two of them died.
Bob Egle was the first to die and he as
cremated.
When the second worker died, Fred Biggs,
then there was a very serious
investigation.
It was suggested, in fact it was suggested
by
Graham Young himself, that this looked
like a thallium poisoning.
So, the investigators went back and
re-investigated Bob Egle's death.
Now, remember, he's been cremated.
But, we're talking about thallium.
Thallium is an element, so thallium cannot
be destroyed.
So they went back to the ashes of the
victim.
They were able to analyze the ashes and
prove the presence of thallium in the
ashes.
Not only could they show that thallium was
present, they could also measure the
level of thallium
and make a very good estimate of the
amount of
thallium present and show that it exceeded
the legal dose.
Well, with this evidence, it led to Graham
Young's conviction of the murders.
This time, he didn't go to a psychiatric
hospital,
he was sentenced to life in prison
and he died in prison some years later.
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Rather bizarrely, Graham Young does still
have his fans.
This is a story from Shizuoka, in Japan, a
few years ago,
where a 17 year old girl fed thallium to
her mother.
The lady didn't die, but she was extremely
ill.
Thalium has some very, very nasty effects.
But the judge realized that this girl did
not hold a grudge against her mother.
She just wanted to do an experiment.
But of course, there's a big difference in
doing an experiment
in a test tube and doing it on a human
being.

