midnight
`` A great vacation day it proved , '' he yawned . `` Bless me , it has been the busiest day I ever lived ! And yet , I 'm glad that I am a doctor-mouse . '' -LSB- Illustration : It was long past midnight when tired old Grand-daddy pulled off his boots . -RSB- The woodland folk were all busy making Neighbor Field-Mouse 's new house when Dr. Whiskers strolled over next morning . `` Good-morning to you all ! '' he cried , waving his cap .