Buttling

What is Pop Glossop doing here as the butler? [...] Are you asking me to believe that Sir Roderick Glossop got up one morning, gazed at himself in the mirror, thought he was looking a little pale and said to himself, "I need a change. I think I'll try being a butler for awhile"? [...] One sees now why Glossop is at Brinkley Court. What one doesn't see is why one finds him buttling.