Once upon a time this observant man went traveling on a train. He was sitting alone in his compartment for a while, but then two people entered; a lady and a gentleman. Soon the gentleman started to behave very ungentelmanish, putting his feet up on the chairs and later lying down to occupy half the places in the compartment and sneezing and so on. Apparently he was sick. The lady was filled with compassion and asked the man about his ailments and, step by step, revealed that she was also suffering from a series of conditions. Now a very lively exchange started. The lady knew all the medicines and sanatoriums where the man could find a cure. The man knew several things he proposed that could help the lady. They took out their notebooks and each of them started to note down the advice of the other for his ailments and giving his advice in turn to the other.
Strangely enough they knew all that could cure the other but nothing that would help themselves.
(I read this story either from Steiner or somewhere in info3.)