Thanks for the replies. In answer to some
questions - I do know the breeder very well and in fact have bought to other Siamese cats from her that I've had no trouble with.
The hair ball thing I will look into. I usually don't treat by kitties for hair balls but I do have a hair ball remedy on hand that I will try on Spence. As far as the vet goes - I have changed vets recently and haven't yet had Spence seen by the new vet. When my previous vet pulled out all of Spences teeth (without notifying me first) I was livid, but after it was all over he gained back the weight he lost and was doing really well until this vomit thing go worse. I suppose I wont worry too much as long as he doesn't lose weight or get dehydrated - just clean up the messes almost every day.