The only issue I have with this is there's a British gallon (that is DIFFERENT from the American gallon) that is used to measure milk. :D. That was the only place I saw gallon being used.
Still british units :D. In 1826 Britain decided to redefine gallon to mean "10 pounds of water". The earlier standard was 231 cublic inches (potentially meant to be 8 pounds of water). The US never adopted the new gallon.
Actually, as much as I dislike imperial units, when it comes to body temperature I do think in Fahrenheit. Mostly because that's how my mum would tell if we were too sick to go to school. 99 - just a little ill, but you can have the day off. 100 - pretty ill, probably at least 3 days off. 101+ - super mega ill, off all week.