He was a dog of long and enlightening experience; and he made it clear that the conjunction of Penrod and Sam portended events which, from his point of view, might be unfortunate.
Duke had a forgiving disposition, but he also possessed a melancholy wisdom.

In the company of either Penrod or Sam, alone, affection often caused him to linger, albeit with a little pessimism, but when he saw them together, he invariably withdrew in as unobtrusive a manner as haste would allow.
"What you doin' ?" Sam asked.
"Nothin'.

What you ?" "I'll show you if you'll come over to our house," said Sam, who was wearing an important and secretive expression.
"What for ?" Penrod showed little interest.
"Well, I said I'd show you if you came on over, didn't I ?" "But you haven't got anything I haven't got," said Penrod indifferently.
"I know everything that's in your yard and in your stable, and there isn't a thing--" "I didn't say it was in the yard or in the stable, did I ?" "Well, there ain't anything in your house," returned Penrod frankly, "that I'd walk two feet to look at--not a thing!" "Oh, no!" Sam assumed mockery.

"Oh, no, you wouldn't! You know what it is, don't you?
Yes, you do!" Penrod's curiosity stirred somewhat.

"Well, all right," he said, "I got nothin' to do.