The Brush Capsule

Miri swallowed the capsule with a sip of water and waited for the clinic's magnetic arm to find it. The brush was no larger than a seed, but it could collect a sample from one short stretch of intestine instead of making her guess where the inflammation began. Her old stool tests showed that something was wrong; none could say where.

By 2042, the human version had entered an early trial after years of bench and animal testing. Miri's symptoms came and went between appointments, and the surgeon wanted one more sample before recommending an operation. The capsule would take only a few millimetres from the intestinal surface, but the magnetic controller could stop it at either of two regions. Her daughter had asked whether pain always had an address.

The external magnet drew the capsule toward the marked segment. The first region matched the place Miri had pointed to on the diagram; the second had never hurt. If she sampled only the painful site, the clinic would learn whether her symptoms matched the local bacteria. If she sampled both, the small brush might not hold enough material for sequencing. Miri selected the second region. A green marker appeared beside a place she had never felt.