Fig. 1. The relationship between blood oxygen affinity calculated at a pH of 7.6, expressed as logP₅₀, and (A) red blood cell haemoglobin content ([Hb]_RBC) as an indicator of cell volume and (B) the relationship between the concentrations of organic phosphates and total haemoglobin ([NTP]/[Hb₄] ratio) within the red blood cells. Open symbols represent data from unfed control snakes measured at 0 h and 48 h, while closed symbols represent data obtained from snakes before (0 h) and after (48 h) feeding. Data are presented as means ± 1 S.E.M. (N=9 for postprandial animals and N=4 or 5 for fasting controls).