A Frog proclaimed himself a physician. A Fox asked the Frog how he can cure others when he can’t cure his own wrinkled appearance. Physician, heal thyself.
A Cobbler’s business had a downturn. The Cobbler decided to try doctoring with a cure-all potion. When he was sick he was asked to drink the potion. No way! Beware of those not trained in their craft.
A Doctor tends a dying patient telling him that all his symptoms are natural and normal. The patient complains that he is ready to die of good symptoms. A death-bed flattery is the worst of treacheries.
A physician comes to cure blindness. On each visit an item is stolen. When he demands payment he gets nothing. Few things are done except for profit.