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 reasonable luck the train will not have gone。〃
They were only just in time； the train moving off as Knighton； the last of the three； swung himself and his suitcase on board。
The conductor remonstrated with them feelingly； and assisted them to carry their luggage back to their partments。 Van Aldin said nothing； but he was clearly disgusted at Poirot's extraordinary conduct。
Alone with Knighton for a moment or two； he remarked：
〃This is a wild goose chase。 The man has lost his grip on things。 He has got brains up to a point； but any man who loses his head and scuttles round like a frightened rabbit is no earthly darned good。〃
Poirot came to them in a moment or two； full of abject apologies and clearly so crestfallen that harsh words would have been superfluous。
Van Aldin received his apologies gravely； but managed to restrain himself from making acid