I recently ran across a great video showing the compatibility of cats and dogs provided the atmosphere is right. In an article on petuniversity.com conditions play an important role in harmony between the two. Puppies and kittens being raised together will break those barriers most times. However many of us get adult dogs or cats and then try to introduce them to each other.

This site advises to go slow, and have a firm grip on each. If it doesn't work, try later. I like that advice. I just don't think you should force animals to get along. Sometimes personalities just don't mesh. However it CAN work. Here's proof in this really sweet video. The two cats are obviously instant caregivers of their new baby.