Carbon dioxide tension and pH of the blood of the lizard Sauromalus obesus at different temperatures

1. 1. In Sauromalus obesus the relationship between pH of carotid blood and body temperature was pH = 7.81−0.017 ( T b ). The blood pH was about 0.2 pH unit less than that of other poikilothermic vertebrates. 2. 2. The pCO 2 at 16, 27 and 40°C was 11, 26 and 40 mm Hg respectively and the plasma HCO − 3 concentration was about 14 mM/l. 3. 3. The OH −/H+ ratio was 6. 4. 4. Either Sauromalus regulates at the lowest OH −/H + ratio of any poikilotherm thus far investigated or these experimental animals suffered a starvation acidosis accompanied by respiratory compensation.