Merrol studied the patterns of waves and lines and splotches. "What is it?"
"Mass-cell radiographs. One was loaned by your employer. The other was taken just after your last operation. Both were corrected according to standard methods. One cell won't do it, ten yield an uncertain identity—but as few as a hundred cells from any part of the original body, excepting the blood, constitute proof more positive than fingerprints before the surgical exchange of limbs. Don't ask me why—no one knows. But it is true that cells differ from one body to the next, and this test detects the difference."
The mass-cell radiographs did seem identical and Dr. Crander seemed certain. Taken altogether, the evidence was overwhelming. There had been no mistake—he was Dan Merrol, though it was not difficult to understand why Erica couldn't believe he was her husband.
"You did a fine job," he said. Recalling the picture of the wreckage, he knew they had. "But couldn't you have done just a little better?"
Crander's eyebrows bounced up. "We're amazed at how well we have done. You can search case histories and find nothing comparable." His eyebrows dropped back into place. "Of course, if you have a specific complaint...."
"Nothing specific. But look at this hand...."