Lettre à la rédaction : Les cheveux de Napoléon, source externe ou ingestion d'arsenic ?

We do not agree that Kintz et al( l) have confirmed that the arsenic in Napoleon's hair was derived from oral ingestion. They showed that an acetone-water wash removed from human hair the arsenic derived from 4 hours suspension in an A s 2 0 3 solution. Perhaps if they had exposed the hair to arsenic for longer it would not have been removed. Smith and Henry(2) were only able to remove 40 % of arsenic derived from 10 days soaking of human hair in a sodium arsenite solution, by washing in water and sodium hydroxide. Also Young and Rice(3) were unable to distinguish between 'internal ' and 'external ' arsenic in guinea-pig hair by washing in acid, alkali, ethanol, or ether. Atalla(4) concluded the same using human hair. We have shown(5) that externally applied arsenic can sometimes be found in the core of human hair and it is difficult to imagine how this could be accessible to cleansing solutions.