I have heard three theories as to why they were blue.  First was they had 
argyria
from drinking acid drinks and eating with silver goblets and flatwear.

Second that they had a genetic disorder due to inbreeding, either the same
disorder as the blue people of Kentucky have, or the one where the heart is
hooked up backwards and pumps into the veins instead of the arteries.

And third, the original royalty was from another planet and they had copper
instead of iron in their blood, like some of the insects do, which gives a 
bluish
green blood. (I believe this one came from http://zetatalk.com but arn't sure)

Marshall

Terry Dickinson wrote:

> Always been my understanding.  Also known as "blue bloods" for the same
> (supposed) reason.
>
> Cheers   Terry
>
> Marsha Hallett wrote:
> >
> > > Subj:   Update on the Solubility of Silver and Selected Silver Alloys in
> > DW
> >
> > Dear Roger,
> > You know, I`d be interested to know if silver really is soluble in wine, as
> > it seems that most of the folks who survived the Black Plague were the
> > Royals and the Nobility, who by and large drank from silver vessels. Be
> > interesting to find that out...
> > Marsha
> >
>
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