In Chapter 3 of Call of the Wild, what did Francois make for Buck, out of what, and why?

Following the attack by the starving huskies that injured
many of the sled dogs and reduced their rations, Perrault and Francois pushed on toward
Dawson, still four hundred miles away. The dogs broke through the thin ice repeatedly,
and Buck's paws--still not used to the intense cold of the frozen ice--were in bad
shape. He whimpered in agony and could not rise to eat his food, so Francois cut away
part of his own moccasins and fashioned four small moccasins for Buck's feet. Francois
also massaged Buck's feet for 30 minutes each evening, and soon Buck was feeling
better.