Opinion  

Too much and you are a foolish tourist, object of gentle scorn. Too little and you are a selfish product of the colonial west, jetting in with your pounds sterling and your suntan oil, expecting the best of Kenya for the change in your pocket.

The right price is reached with a double handshake - a firm grip and then another, saying not just that you mean this business, but that you really mean it.

Tourists are scarce this year so Ali is delighted to strike a deal, even though he is condemning himself to three hours in the company of four Selby girls who think that sharks spend their days plotting to jump over reefs with the express intent of landing in glass-bottomed boats and eating the contents thereof.

We enjoyed the bartering. We will also enjoy, after the trip, giving Ali what he first asked, for the difference between the two means so much more to him. It isn't just the relative economics of the situation, but the true meaning of the money. For Ali is too thin and has a very large lump in his neck. He has seen someone. The government doctor gave the lump a name but Ali can't remember it, nor the name of the medicine, but it costs £35 so he has to save the money before he can have it. Hence his new venture renting his brother's boat.

The difference between our saving face and looking foolish could mean survival for Ali, but he only mentions when we ask. It's just life, he says. I reflect on Mrs Ill, who seeks me out repeatedly to discuss the difference between her certainty that she has a weak immune system and my certainty that she doesn't - a well woman determined to be ill.

Ali, on the other hand, is determined to be well, although he doesn't need to say immunity for us to guess where the problem lies. Perhaps if he had been more like Mrs Ill, he wouldn't be in this position. And we would never have seen the reef in his boat. Strange old world.

• Dr Selby is a GP from Suffolk. Email her at GPcolumnists@haymarket.com