How do you tell when your cat is ill?

I've heard that if your cat haunch sits and the haws sp??? appear in the corner of their eyes (that being the third eyelid) then it's a good indication that your kitty is ill and should see a vet. Are there any other ways you can detect when your cat is ill, other than the obvious, vomit, lameness etc?

Purrley; Other than obvious symptoms, an ill kitty will also not be as playfuls as they should be, or once were. My Snow cat was ill, but I didn't recognize the extent of it until I took him to the vet for a check up. He sounded like he had bronchial congestion, and difficulty in breathing. She gave me some antibiotics which I gave him for 3 days, and then he came out of it. Now he plays with the other kittens (being about 4 months old) in a much more vigoruous manner than before.

Wayne

Cats also hide when they are not feeling well. Even a cat that is normally friendly will hide somewhere, like under the bed, and will not want anything to do with you.