A lab test and a cat scan

A MAN TAKES HIS SICK CHIHUAHUA TO THE VET. A Labrador retriever comes in, sniffs the dog and leaves. Then a cat enters, stares at it for a while and leaves. The vet returns and hands over a $250 bill.

The man says, “$250? I was here only 20 minutes!”

“That’s right,” says the vet. “$100 for the lab test and $150 for the cat scan.”