Starting on postnatal day 10 mice received daily injections of either E. coli (O55:B5) lipopolysaccharide (LPS, solid squares, n=6) 0.2 mg/kg in 0.9% NaCl i.p. daily for 3 days, then 0.1 mg/kg for 2 days, or 0.9% NaCl (NS, open circles, n=5) 0.1 ml i.p. daily for 3 days, then 0.05 ml for 2 days. Esophageal temperature was measured to the nearest 0.5 °C with an analog telethermometer (see Methods) immediately prior to injection on day 1 (d1) of the injection course (e.g. pre d1 on x-axis), and 2 and 4 hours post-injection (e.g. 2h d1 and 4h d1, respectively), daily throughout the 5-day injection course. Error bars are ± 1 standard deviation about the mean values.