The issue focused on low concentration hydrogen ions (HCI) from plasma sources as high heat storage devices for plasma oxygen (PO 2 ). Consistent with previous claims that plasma oxygen has important biological functions in tissue oxygenation and hemoglobin synthesis, both plasma oxygen levels and plasma HCI concentrations were observed in tissue oxygenation experiments ( Fehr et al., 1999 ). Most importantly, plasma HCI concentrations were observed in tissue oxygenation experiments which clearly demonstrate that plasma HCI increases both within and without tissue oxygenation ( Lind