If you could prevent the normal scattering at the interface, you could reveal the structures underneath, effectively rendering skin transparent. [Zihao Uo] and others demonstrate this in a paper ...

Researchers have found that common food dye can be used to make skin, muscle and connective tissues temporarily transparent, suggesting that the procedure could be used in future to locate cancer ...

This is largely why even thin layers of tissue and their surrounding fluids, such as those making up an animal's skin, aren't ...