De Gaulle trained his men hard (a river crossing exercise of the freezing Moselle River at night was vetoed by his commanding general). He imprisoned a soldier for appealing to his deputy (member of parliament) for a transfer to a cushier unit, and when investigated initially tried to invoke his status as a member of the "Maison Pétain", eventually appealing to Pétain to protect himself from a reprimand for interfering with the soldier's political rights. An observer wrote of de Gaulle at this time that although he encouraged young officers, "his ego...glowed from far off". In the winter of 1928–1929, thirty soldiers ("not counting Annamese") died from so-called "German flu", seven of them from de Gaulle's battalion. After an investigation, he was singled out for praise in the ensuing parliamentary debate as an exceptionally capable commanding officer, and mention of how he had worn a mourning band for a private soldier who was an orphan earned an exclamation of praise from the Prime Minister Raymond Poincaré.