He’d coloured in a patch of the white mouse’s fur with a black felt-tip pen

From Science Fictions by Stuart Ritchie.  Page 54.

One of the best-known, and most absurd, scientific fraud cases of the twentieth century also concerned transplants – in this case, skin grafts. While working at the prestigious Sloan-Kettering Cancer Institute in New York City in 1974, the dermatologist William Summerlin presaged Macchiarini by claiming to have solved the transplant-rejection problem that we encountered above. Using a disarmingly straightforward new technique in which the donor skin was incubated and marinated in special nutrients prior to the operation, Summerlin had apparently grafted a section of the skin of a black mouse onto a white one, with no immune rejection. Except he hadn’t. On the way to show the head of his lab his exciting new findings, he’d coloured in a patch of the white mouse’s fur with a black felt-tip pen, a deception later revealed by a lab technician who, smelling a rat (or perhaps, in this case, a mouse), proceeded to use alcohol to rub off the ink. There never were any successful grafts on the mice, and Summerlin was quickly fired.