"Anatomy has its uses even in a midnight scuffle.
"The suddenness of my appearance and the promptness of my action paralyzed him completely. He stared at me in abject terror and gibbered inarticulately. Only for a few moments, however. Then he turned and darted towards the street door.
"But I did not mean to let him escape. In a twinkling I was after him and had him by the collar. He uttered a savage snarl and dropped the lamp on the mat to free his hands; and, as the spring switch was released, the light went out, leaving us in total darkness. Now that he was at bay, he struggled furiously, and I could hear him snorting and cursing as he wriggled in my grasp. I had to drop the concussor that I might hold him with both hands, and it was well that I did, for he suddenly got one hand free and struck. It was a vicious blow and had it not been partly stopped by my elbow the adventure would have ended very differently, for I felt the point of a knife sweep across my chest, ripping open my pajama jacket and making a quite unpleasant little flesh-wound. On this I gripped him round the chest, pinioning both his arms as well as I could and trying to get possession of the knife, while he made frantic struggles to aim another blow.
"So, for awhile we remained locked in a deadly embrace, swaying to and fro, and each straining for the momentary advantage that would have brought the affair to a finish. The end came unexpectedly.
"One of us tripped on the edge of the mat and we both came down with a crash, he underneath and face downwards. As we fell, he uttered a sharp cry and began to struggle in a curious, convulsive fashion; but after a time he grew quieter and at last lay quite still and silent.
"At first I took this for a ruse to put me off my guard, and held on more firmly than ever; but presently a characteristic limpness of his limbs suggested a new idea. Gradually and cautiously I relaxed my hold, and, as he still did not move, I felt about on the mat for the lamp; and when I had found it and pushed over the switch I threw its light on him.
"He was perfectly motionless and did not appear to be breathing. I turned him over and then saw that it was as I had suspected. He had held the knife ready for a second blow when I had pinioned him. He was still grasping it so when we fell, and the point had entered his own chest near the middle line, between the fourth and fifth ribs, and had been driven in up to the very haft by the force of the fall. He must have died almost instantaneously.