Last night Tilla ran into the house from the furthest corner of the yard at full speed.  I was thrilled.  Saturday I brought him to the vet.  He was not putting any weight on his left front paw.  The vet gave us an anti-inflammatory pill and three pills later he was back running at full speed.  The vet said the pill would work fast.  And it did.  He is back to running and is no longer limping.