Looking at it more intently, he saw a black object turning in the water like a porpoise, and then the unmistakable uplifting of a black arm in an unskillful swimmer's overhand stroke.

It was a struggling man.

But it was quickly evident that the current was too strong and the turbulence of the shallow water too great for his efforts.

Without a moment's hesitation, clad as he was in only his shirt and trousers, Morse strode into the reeds, and the next moment, with a call of warning, was swimming toward the now wildly struggling figure.

But, from some unknown reason, as Morse approached him nearer the man uttered some incoherent protest and desperately turned away, throwing off Morse's extended arm.
Attributing this only to the vague convulsions of a drowning man, Morse, a skilled swimmer, managed to clutch his shoulder, and propelled him at arm's length, still struggling, apparently with as much reluctance as incapacity, toward the bank.