gnizing her husband with surprise and a trace of anxiety； and Derek Kettering discovering that his wife was travelling on the train。 He tested various possibilities； such as the best way for a person to conceal himself in the second partment。
Then suddenly an idea seemed to strike him。 He clutched at Van Aldin's arm。
〃Mon Dieu； but that is something I have not thought of！ We must break our journey in Paris。 Quick； quick； let us alight at once。〃
Seizing suitcases he hurried from the train。 Van Aldin and Knighton； bewildered but obedient； followed him。 Van Aldin having once formed his opinion of Poirot's ability was slow to part from it。 At the barrier they were held up。 Their tickets were in charge of the conductor of the train； a fact which all three of them had forgotten。
Poirot's explanations were rapid； fluent； and impassioned； but they produced no effect upon the stolid…faced official。
〃Let us get quit of this；〃 said Van Aldin abruptly。 〃I gather you are in a hurry； Monsieur Poirot。 For God's sake pay the fares from Calais and let us get right on with whatever you have got in your mind。〃
But Poirot's flood of language had suddenly stopped dead； and he had the appearance of a man turned to stone。 His arm still outflung in an impassioned gesture； remained there as though stricken with paralysis。
〃I have been an imbecile；〃 he said simply。 〃Ma foi； I lose my head nowadays。 Let us return and continue our journey quietly。 With re