I was thinking just now of different ways society used to think, versus what people in general know now.

What reminded me is that I'm currently down with a virus, and I'm running a slight temperature. It brought to mind how during my childhood, people tended to think a "normal" body temperature was a constant, exact 98.6 degrees Fahrenheit. (37 Celsius.) There was even an arrow marking that point on the old glass tube thermometers. The mercury going past the arrow was the *only* acceptable proof that you're actually sick, and not just trying to weasel out of school. Say you're a kid in the 1970's, and you tell your parent, "I don't feel good." Parent touches your forehead and is instantly skeptical. "Well, you're not warm." In goes the thermometer. The mercury is right at the arrow. Anything else you've got going on--stuffy nose, sore throat, nausea, whatever--it doesn't matter. No fever, no sick day.

This worked in the other direction too. You're a kid in the 1970's. You've been down with the flu, but you feel better now, and you want to get out of bed. Parent checks your temperature. It's 99. "Nope. You're still sick." Nowadays more people undestand that it's not the only indicator, and that "normal" is a range, rather than a point. Some people run warmer than others, and everybody fluctuates. A person running 99.5 (37.5) may be fine. Another person running 98.6 may be very ill.

Also along these lines, when our parents made us wait an hour after eating lunch before we could get back in the pool. Not necessary, medical science now knows.

Can you think of any others?