Doctors on Wednesday implanted a feeding tube in Israeli Prime Minister Ariel Sharon's stomach, said a statement from Jerusalem's Hadassah Hospital, where he is being treated for a massive stroke. Since he was stricken on Jan. 4, Sharon has been in a coma. Experts in long-term care and a US authority on comatose patients have examined Sharon in recent days. "Tonight Prime Minister Ariel Sharon underwent a gastrostomy, a process in which a tube is inserted into the stomach for feeding," the statement said. "The procedure was carried out under anesthetic and was successful. The prime minister's condition continues to be critical and stable."