They maintained that the potassium tartrate used in his treatment prevented his stomach from expelling these compounds and that his thirst was a symptom of the poison. Their hypothesis was that the calomel given to Napoleon became an overdose, which killed him and left extensive tissue damage behind. According to a 2007 article, the type of arsenic found in Napoleon's hair shafts was mineral, the most toxic, and according to toxicologist Patrick Kintz, this supported the conclusion that he was murdered.