Holmes’ assistant, Dr. Watson, was quite upset and fretted to Holmes that now they would never be free of Moriarity’s evil, harrassing schemes. Holmes was unfazed, however, quietly puffing on his pipe.
Watson demanded to know how Holmes could remain so calm. Holmes replied that he would indeed have the sought-after key in his possession in rather short order.
In desperation, Dr. Watson asked how Holmes could be so sure of recovering the ingested key. Taking a long draught on his pipe and blowing a satisfying cloud of smoke, Holmes smiled and replied,
“It’s alimentary, my dear Watson… alimentary!”