The vet goes into the back room and comes out with a cat and puts the cat down next to the dog's body. The cat sniffs the body, walks from head to tail, poking and sniffing the dog's body and finally looks at the vet and meows.
The vet looks at the man and says, "I'm sorry, but the cat thinks that your dog is dead, too."
The man, finally resigned to the diagnosis, thanks the vet and asks how much he owes. The vet answers, "$350."
"$350 to tell me my dog is dead?!" exclaims the man.
"Well," the vet replies, "I would only have charged you $50 for my initial diagnosis. The additional $300 was for the cat scan."