Many years ago, when I was a platoon leader in an Army medical company, I was kibitzing while one of the senior NCOs was teaching the junior medics a class on how to run labs — specifically how to check for sugar content in urine. Unbeknownst to the young troops, before the class started (and while I was watching) the NCO had filled a sample container with apple juice.
“With some experience,” the NCO told the class, “you can even tell the sugar content of urine by tasting it.” He took a sip of the juice from the sample container, swirled it around in his mouth, and swallowed. “Yep,” he said, “Too much sugar – this guy’s diabetic.”
The class of young medics exclaimed in horror. Then the NCO said, “No, you dummies, this is apple juice,” and had a couple of them smell it. Then he said to one of them, “OK, Private Snuffy, go out in the company area, find someone else. I’ll let you…