A guy goes to the doctor with tennis elbow. Instead of examining him, the doctor asks for a urine specimen and makes his diagnosis from that. The man is confused so the doctor explains that he has a new machine that can diagnose any physical condition from a single specimen. The doctor prescribes medication and tells the man to come back in a week with another specimen. The man doesn't believe the doctor's machine is for real so he decides to test it. To confuse the doctor, he has his wife and teenage daughter provide the specimen. Then, to confuse things more he masturbates into the bottle. On his way to the doctor he has the brilliant idea of adding a drop of motor oil from his car's dipstick.
The doctor analyzed odd looking specimen and called the man into his office. The doctor delivers the grim news to the patient: "your daughter is pregnant, your wife has herpes, your car is about to throw a rod and if you don't stop beating off, that tennis elbow will never heal!"
Universities are full of knowledge. The freshmen bring a little in and the seniors take none away and knowledge accumulates.