Transparent rats

Flesh has been made invisible. By injecting glycerol into the skin of rats
and hamsters, Ashley Welch of the University of Texas and his colleagues made
small areas of flesh nearly transparent. Glycerol’s refractive index closely
matches that of collagen, so light isn’t scattered nearly so much. “It’s amazing
how well it works,” Welch says. The method only allows you to see 4 or 5
millimetres into the body. But this could be enough to make laser treatments
easier.