And his sorrowful eyes took on a deeper woe.

By the way, if there is anything more sorrowful than the eyes of a collie pup that has never known sorrow, I have yet to see it.
No, Lad could not howl.

And he could not hunt for squirrels.

For these enemies of his were not content with the unsportsmanliness of climbing out of his reach in the daytime, when he chased them; but they added to their sins by joining the rest of the world,--except Lad,--in sleeping all night.

Even the lake that was so friendly by day was a chilly and forbidding playfellow on the cool North Jersey nights.
There was nothing for a poor lonely pup to do but stretch out on his rug and stare in unhappy silence up the driveway, in the impossible hope that someone might happen along through the darkness to play with him.
At such an hour and in such lonesomeness, Lad would gladly have tossed aside all prejudices of caste,--and all his natural dislikes, and would have frolicked in mad joy with the veriest stranger.