“What you see in this row of baths are kidneys that have been created from stem cells derived from fibroblasts—connective tissue cells—of specific mice.” Yamamoto tried to interrupt to say that Rothman was covering material that had already been mentioned, but he couldn’t get Rothman’s attention. Rothman was on a roll. “I wear these magnifying lenses so I can work with the lines, but take my word for it, each organ is hooked up to a pump that circulates a blood-like solution into the kidney’s main artery and out its main vein. It’s connected by a cannula, or thin tube, from its ureter to a port where its urine output can be sampled. That’s one of the functions performed by the monitoring unit beneath the bath. All the data is collected in the mainframe so we can see how tiny fluctuations in conditions affect the kidney and its development.

“Each kidney will soon be implanted back into the same mouse that supplied the original fibroblasts. We’ve already done this twice with no rejection phenomena whatsoever.” With his hand, Rothman gestured toward another group of baths. “These vessels contain pancreases, which have quite different needs than kidneys. Initially we had more difficulty getting the organogenesis process to start than we had with the kidneys, but those initial reverses have been solved, and we are now doing equally well. With the pancreases, we have had to be very careful about the integrity of the connections with the pancreatic duct since the pancreatic secretions contain digestive enzymes. Initially some of our preparations digested themselves.”

“Have there been any problems with teratomas?” Pia asked. In contrast to the others, she did not feel intimidated by Rothman. She knew that teratomas, a kind of developmental tumor, were something feared by stem cell biologists.

For a moment Rothman faltered. He had not been expecting to be interrupted in his prepared remarks. Except for the sound of moving fluid emanating from all the organ baths, a brief silence reigned.

“No teratomas at all,” Yamamoto said, coming to his boss’s aid. He was well aware of his boss’s quirky personality.

As if he had forgotten the students’ and Yamamoto’s presence, Rothman’s attention diverted to the appearance of a small blinking light accompanied by a pinging noise coming from the control panel of one of the baths. Without a second’s thought or explanation, Rothman headed in its direction, slipping his goggles back on as he walked.

“That’s an alarm that some aspect of the bath’s parameters has started to change,” Yamamoto explained.

The students watched him go. Lesley and Will were awed at having been in the famous researcher’s presence and having survived without being belittled. Pia was impressed by the alarm: “What would have happened if no one had been in here to hear the alarm?”

“Not a problem,” Yamamoto said. “All information is followed in real time by the university’s mainframe, and Dr. Rothman and I have apps on our iPhones such that we would have been instantly alerted.”