With the beginning of cold weather little Tim’s health rapidly improved. Soon he was strong enough to go sliding on the ice; and when Barker had a blacksmith at the landing make a pair of skates for each of the boys the joy of the lads was unbounded.
They skimmed lightly over the frozen sloughs, where the trees and banks sheltered them from the wind. From these trips they returned with flushed cheeks and ravenous appetites and many stories of what they had seen.
They had chased pickerel and other fish under the clear ice, they had seen a muskrat swim along with an air bubble attached to his nose, and they had watched clams slowly plowing their furrow in the sand as they withdrew from the shallower banks into deep water.
The Mississippi and its tributaries harbor a large variety of clams whose shells are now used for pearl buttons. The boys were curious about the habits and life of these quiet creatures that were always nearly buried in mud and sand and moved about by queer little jerks. When Tim was still too weak to move about much, he had amused himself for hours dropping clams, which Bill had caught, back into the water, and watching how each shell, slowly opening, put out a sort of white, fleshy foot; slowly righted itself, and crawled away into deep water.
“What do clams eat and how do they spawn?” the boys wanted to know, but on these questions neither trapper nor Indian had any information.
Clams do indeed lead a strange life. They cannot run after their food, so they just open their shells a bit to allow the water to run through, in order to catch any small particles of food the water may contain.
The young clams just hatched are so small that the naked eye can scarcely see them. They have no shell at all and swim about very actively. As soon as possible they attach themselves to the gills of several kinds of fish. The fish do not like it, but they have no way of escaping from the very minute creatures. Embedded in the gills of fish the young clams live for some weeks looking like small pimples. When they have grown a tiny shell they drop to the bottom of the river or lake and begin to live in the usual way of clams. That is the curious life-history of the river clam.
While the skating lasted the boys were well occupied. The camp was run on the plan of two meals a day. Barker and the Indian set a few traps for muskrats and minks, tidied up the cabin, cooked the meals, washed dishes, and cut wood. In all these occupations the lads gladly took a hand. At times they went the round of the traps with the men. When the weather was fine they went on skating trips up and down the glassy ice of the sloughs, which reflected like a mirror the boys at play and the trees on shore.
One who has skated only on artificial rinks and ponds does not know the thrill of traveling on a smooth winding river or on the transparent expanse of a frozen lake.
Tim tired very easily, but he grew visibly stronger every day. His fever had entirely disappeared.