With what two men does marlow meet in Brussels?

Marlowe goes to Brussels to meet his employers and to visit the doctor. Neither one of the men are addressed by name.

"From behind that structure came out an impression of pale plumpness in a frock-coat. The great man himself. He was five feet six, I should judge, and had his

grip on the handle-end of ever so many millions. He shook hands, I fancy, murmured vaguely, was satisfied with my French. BON VOYAGE."

"‘There was yet a visit to the doctor. ‘A simple formality,’ assured me the secretary, with an air of taking an immense part in all my sorrows."