Each mouse was weighed on Day 1 before the lights went out. On the same day, starting at 3 hours after lights off, the single water bottle was removed from the cage of each mouse and replaced with a single tube containing 20% ethanol in tap water (v/v). Tubes were read again at 2 hours, the volume change recorded, and each tube was replaced by the standard water bottle. On Day 2, the procedure was repeated exactly, but tubes were left in place at the 2 hours reading for an additional 2 hours. At 4 hours, a 20-µL blood sample was drawn from the periorbital sinus with a capillary tube. Care was taken to be as quiet as possible and to disturb the mice minimally.
