ANIMAL DOCTOR <P>Tuesday, January 14, 2003; Page C09 <P>Dear Dr. Fox: <P>We adopted our cat, Barcelona, from the<BR>humane society 10 years ago. Although<BR>initially cowering and shy, he has become a<BR>sweet, chatty member of the household.<BR>Once that happened, we attempted (about<BR>eight years ago) to bring a spayed female in<BR>to provide him with companionship. <P>Their start was rocky, but they got along<BR>fairly well after the first month or so. After that they became territorial about the litter box, and it became their battleground.<BR>Eventually their hissing and going to the<BR>bathroom throughout the house became<BR>intolerable, and we returned the sweet but<BR>feisty female to the Humane Society,<BR>knowing that since she was gorgeous and<BR>young, she'd soon be adopted. <P>Now we would like to try again to find a<BR>companion for Barcelona, thinking that<BR>perhaps now that he's older he might<BR>tolerate and get pleasure from a young cat. However, with our past experience and his current fussiness about his litter box (since his attack of and recovery from cystitis), we wonder if this plan would work. We'd appreciate your advice. <P>P.J.H., Silver Spring <P>One of the tricks in keeping the peace in a home where there are two or more cats is to make sure there are places where the cats can get out of each other's sight when they need "visual space." <P>This is especially critical for some cats around eating, sleeping and toilet areas. So putting up a small screen or panel between two or more litter boxes and food bowls can be of great help in avoiding feline conflict.<P>You must also constantly supervise the cats when they first come together, ideally keeping the new cat in a separate room for a few days (with brief periods of supervised interaction) so that they get used to each<BR>other's scents and sounds.<P>If possible, put a cat gymnasium or well-secured long tree branch in the corner of one room for one or both cats to be able to "go vertical." Cats often feel more secure when they are off the ground and able to<BR>look down on the world.<P>With patience and vigilance your success in bringing in a feline companion for Barcelona will surely be rewarded by a happier and healthier cat. Also, Barcelona might lose some weight chasing his new playmate through the house -- which, generally, is not a bad thing.