‘I should be greatly obliged.’

A walk of a few yards brought them to the chemist’s shop. M. Pascot was a large, bald-headed man, with a high colour and a consequential manner.

‘Good-day, M. Pascot,’ the waiter greeted him deferentially. ‘This gentleman is a friend of mine, a detective, and he is engaged on an inquiry of much importance. You remember the man with the black beard who was lunching in the café the last day you were in? He was sitting at the little table in the alcove and then he began telephoning. You remember? You asked me who he was.’

‘I remember,’ rumbled the apothecary in a deep bass voice, ‘and what of him?’

‘My friend here wants to find out what day he was at the café, and I thought perhaps you would be able to tell him?’

‘And how should I be able to tell him?’

‘Well, M. Pascot, you see it was on the same day that you were with us, and I thought maybe you would be able to fix that date, the day Madame was in Paris—you told me that.’

The pompous man seemed slightly annoyed, as if the waiter was taking a liberty in mentioning his personal concerns before a stranger. La Touche broke in with his smooth suavity.

‘If, M. Pascot, you could do anything to help me, I should be more than grateful. I should explain to you that I am acting on behalf of an innocent man,’ and he drew a pathetic picture of the evil case in which Felix found himself, ending up by delicately insinuating that a reward for suitable information was not out of the reckoning.

M. Pascot thawed.