Thursday, September 15th:   PARIS (AFP) - Algerian President Abdelaziz Bouteflika, who has been hospitalised in Paris for over a fortnight, "likely" has stomach cancer, a leading French doctor said based on a description of his symptons.   "It is very hard to make a diagnosis. If it is true that he first suffered gastrointestinal blood loss, then it is likely to be stomach cancer," Bernard Debre, head of the urology department at Paris's Cochin hospital, siad Thursday.   "I say likely, because I cannot see what else it could be," the doctor, who did not personally examine Bouteflika, told France Inter radio.   The 68-year-old Algerian leader was operated for a "bleeding stomach ulcer", according to a medical statement issued on December 5 -- the only official information about his condition since he was hospitalised on November 26.   Algerian officials have since said Bouteflika was recovering normally in hospital, but there has been worried speculation that his condition may be more serious than publicly admitted.