Instrumentation: Pen-line Diagnosis

The visiting doctor at the A.M.A. meeting had just had a little blood drawn from his arm. He watched while a technician dropped the specimen into the machine. Within a minute, he saw pastel-colored samples of his diluted serum being pumped through a dozen spaghetti-thin plastic tubes. Lights began to flash on and off, and a mechanical pen started to trace a red line on a chart. The doctor noted with equanimity that the thin red line passing through the columns of the chart was reporting normal amounts of calcium, albumin and...