See here, this is where he gripped him, and tried to get the knife in.

They fell over together there.
Harry was played out and bleeding hard, or that man would never have got away when he once had his hands on him." Seaforth stared at the rent-down undergrowth, and had no great difficulty in reconstructing the scene.

Smashed fern and scattered leaves as well as the red smears on the snow bore plain testimony to the fierceness of that struggle, and he pictured his comrade grappling with his adversary while his strength flowed from him with that horrible red trickle.

The light that came down between towering trunks showed that his face was grey and stern, and Okanagan, who looked at him, nodded as it were approvingly.
"I've seen enough," said the former.

"If I can find that man he will not get away from me." "Well," said Okanagan simply, "we're short of the bullet now, and I'll know better what to do with Harry when we find it.