I had about made up my mind to go and speak to Goodenough in English, when Grim appeared.

Not even Goodenough recognized him, his Syrian stride was so well acted.

He saluted, and the salute was returned punctiliously but with that reserve toward a foreigner that the Englishman puts on unconsciously.

When Grim spoke to him in Arabic Goodenough answered in the same language.
I did not hear what was said at first, but as I drew closer I heard the sequel, for Grim changed suddenly to English.
"If you can't recognize me through that magnifying-glass of yours, colonel, I must be one leopard who can really change his spots.

I'm Grim.