adding to the family

Question
I have an 8 year old Maine Coon mix that I adopted about 4 years ago.  Recently, we added a 6 1/2 month old Siamese mix to the family (both are female).  You probably won't be surprised to hear that my big baby and my little baby don't get along.  The kitten has been around for about 3 months, though we have only all lived alone together for about a week.  The cat and the kitten hiss pretty much every time they catch sight of each other.  They glare and they growl, they threaten and they pace.  If this was all they did, I could deal with that.  However, the cat has started attacking the kitten. She has attacked 4 times in the last 24 hours.  If I am in the room and awake, it doesn't go beyond hissing and growling, but as soon as I walk out of the room someone loses some fur.  It is rapidly getting to the point where I am afraid to leave them alone.  What can I do to help them tolerate each other, if not become friends?

Answer
Hi Amy!
Cats do not like change and this is a major change.
Your Maine Coon mix needs more time to get used to having another cat around.  I would separate them, let them sniff each other under the door for awhile.  Put one of them in a room with litter box and food,  then after a few days, switch them. This works good for when you are not at home.  They can get used to each other's smell this way.  You don't need to leave the kitten alone with your adult cat. It sounds to me like the Maine Coon is jealous.  This will take some time, but if you take it slow... they will probably eventually be best of friends.  The siamese is seen as an intruder right now, so be very careful to give your adult cat lots of love and attention.   After each of them have had a few days in the room, slowly... slowly... start letting them out together for awhile, makeing it a little bit longer each time.   If you are patient I think you will see some results.

God Bless,
Becky