Doctor house calls on pets?

[lisa4]

I am new to the medical profession and I am trying to make a house call, but the patient is apparently a cat. Can cats be patients or is this a glitch? I make the call and it says to go to "Evilgenius's  [name of the cat] house". I go there and then a notice with the cat's face comes up and he says: "Hi, I'm Evilgenius. Thanks for checking up on me...ect." Then I ring the door bell and nothing happens. (I suppose a cat can't really open the door) then I try to make another house call and it says no one needs checking up. This happened twice already.