“Now, Mma, that was not a busy afternoon and I was able to catch up on the filing of the patient records. Every so often I go through the files just to check up that all the records are in the right order. The doctor gets very cross if he cannot have the records on his desk when a patient comes in to see him. Well, I was sorting out the records and I came across the record of the man who had come for the three o’clock appointment. And I noticed that the latest entry was about the consultation that this man had just had.”

Boitelo paused. Mma Ramotswe was sitting quite still, as was Mma Makutsi. The nurse had a simple, direct way of talking, and the two women had been caught up in her narrative.

“I see,” said Mma Ramotswe. “The record. Yes. Please go on, Mma. This is a very interesting story.”

Boitelo looked down at her hands. “The doctor had taken his blood pressure and had entered the reading. It was very high.”

Mma Ramotswe frowned. “Does blood pressure go up and down?”

The nurse shrugged. “It can do. If you are very excited your blood pressure can go right up, but it doesn’t seem very likely, does it?”

Mma Makutsi now intervened. “Perhaps there was something wrong with the instrument. Things go wrong, you know, with these complicated machines.”

Boitelo half-turned to stare at Mma Makutsi. “These instruments are very simple,” she said quietly. “They are not complicated machines.”

“Then it must have been a mistake,” said Mma Ramotswe. “Does the doctor drink over lunch?”

“He never drinks,” said Boitelo. “He says that he does not like the taste of alcohol, and he also says that it is far too expensive. Water is cheaper, he says.”

There was a brief silence as Mma Ramotswe and Mma Makutsi contemplated the possibilities. Neither was sure about the significance of the misreading—if that was what it was. It sounded important, but what did it mean? Doctors made mistakes all the time—as everybody did—and why should this make the nurse so anxious? It seemed that an important part of the story was yet to come, and this was what Boitelo now provided.