Crouching low, he wagged his tail in ardent invitation to the stranger to chase him and get back the satchel.

Thus did the Master romp with Lad, when the flannel doll was the prize of their game.

And Lad loved such races.
Yes, the stranger was accepting the invitation.

The moment he had crawled out on the veranda he reached down for the bag.

As it was not where he thought he had left it, he swung his groping hand forward in a half-circle, his fingers sweeping the floor.
Make that enticing motion, directly in front of a playful collie pup; specially if he has something he doesn't want you to take from him;--and watch the effect.
Instantly, Lad was athrill with the spirit of the game.