Already reproduced, no gloves needed

A neuroscientist visiting a longtime collaborator's lab found him injecting dye. The method was standard: put a little crystal in a piece of fixed tissue, put the tissue in the fridge, and the fluorescent dye labels a set of neurons in a pathway. He wasn't wearing any gloves.

The dyes were carbocyanide dyes, so the visitor asked whether he wanted to put some on. He looked up from the microscope, announced he had already successfully reproduced, and went back to the tissue.

Everyone else in the lab was following safety protocol. It was his lab.