It is recounted that at King's College in the Strand around the time of the
war, the Chief of Services would inevitably begin the year's rounds by
teaching "a singularly important principle of medicine." He asked a nurse
to fetch him a sample of urine. He then talked at length about Diabetes
mellitus. "Diabetes," he said, "is a greek name; but the Romans noticed that
the bees like the urine of diabetics, so they added the word mellitus which
means sweet as honey. Well, as you know, you may find sugar in the urine
of a diabetic ..."
By now the nurse had returned with a sample of urine which the
registrar promptly held up like a trophy. We stared at that straw-colored
fluid as if we had never seen such a thing before. The registrar then
startled us. He dipped a finger boldly into the urine, then licked his
finger with the tip of his tongue. As if tasting wine, he opened and closed
his lips rapidly. Could he perhaps detect a faint taste of sugar? The sample
was passed on to us for an opinion. We all dipped a finger into the fluid,
all of us foolishly licked that finger.
"Now," said the Registrar grinning, "You have learnt the first
principle of diagnosis. I mean the power of observation." We were baffled.
We stood near the sluice room outside the ward, and in the distance, some
anonymous patient was explosively coughing. "You see," the registrar said
continuing triumphantly, "I dipped my MIDDLE finger into the urine, but
licked my INDEX finger -- not like all you chaps.