"Quick Diagnosis" joke

A young doctor moved to a small, remote town to replace the elderly doctor who was preparing to retire. When he was making his rounds, the older doctor suggested that the younger one accompany him so the residents could meet him and get used to having a new doctor.
The woman at the first house they visited complained of feeling sick to her stomach.
The older doctor said, "Perhaps you've been overdoing it with the candy and sweets. Why not cut back on the amount you've been eating and see if that does the trick?"
As they left, the younger doctor said, "How on earth did you come to your diagnosis so quickly? You didn't even examine that woman."
"I didn't have to examine her," explained the older doctor. "You noticed I dropped my stethoscope on the floor in there? Well, when I bent over to pick it up, I noticed a lot of candy wrappers in the trash. Most likely, that was what was causing her to feel sick."
"Pretty sneaky," replied the younger doctor. "I think I'll try that at the next house."
At the next house they visited, they spent a few minutes talking with an elderly woman. She complained that she didn't seem to have as much energy as she used to have.
"I don't know what's wrong, doctor, but I've been feeling very tired and run down lately," she said.
"You've probably been doing too much work for the church," the younger doctor said. "Maybe you should cut back a bit and see if that helps."
When they left, the older doctor said, "Your diagnosis is probably right, but how did you arrive at it?"
"Well, just as you did at the last house, I dropped my stethoscope," the younger doctor explained. "When I bent down to pick it up, I caught sight of the preacher under the bed."