“One of the things that I didn’t do,” continued Boitelo, “was to take the blood pressure of patients. All nurses can do that. There is an instrument which you wind round the patient’s arm and then you pump a bulb. You will have had your blood pressure taken, Mma? You will know what I am talking about.”

Mma Ramotswe did. Her blood pressure had been taken and had caused her doctor to say something to her about trying to keep her weight down. She had tried for a short time, and somehow had failed. It was difficult. Sometimes doctors did not know how difficult it was. Traditionally built doctors did, of course, but not those young thin doctors, who had no feeling for tradition.

“My blood pressure was a bit high,” said Mma Ramotswe.

“Then you should lose weight,” said Boitelo. “You should go on a diet, Mma Ramotswe. That is what I have to say to many of the ladies who come to the clinic. Many of them are … are the same shape as you. Go on a diet and reduce your salt intake. No biltong or other things with lots of salt in them.”

Mma Ramotswe thought that she heard Mma Makutsi snigger at this, but she did not look in her assistant’s direction. She had never been told before by a client to go on a diet, and she wondered what Clovis Andersen would make of such a situation. He was always stressing the need to be courteous to the client—indeed, there was a whole chapter on the subject in The Principles of Private Detection—but it said nothing, she thought, on the subject of clients who told one to go on a diet.

“I will think about that, Mma,” she said politely. “Thank you for the advice. But let us get back to this thing that you found out. What has it got to do with blood pressure?”

“Well,” said Boitelo, “I was rather surprised that I was never asked to take the patients’ blood pressure. The doctor always did that, and he kept the sphygmomanometer in his room, in a desk drawer. I saw him using it if I came into the room to give him something, but he never let me use it. I thought that maybe it was because he liked pumping up the instrument—you know how men are sometimes a bit like boys in that way—and I did not think too much about it after that. But then one day I used the instrument myself, and that was when I had a big surprise.