Another famous example: The magic of the Golgi stain, which first produced pictures of neurons, was that it stained only a tiny fraction of the cells. That's wh

Another famous example: The magic of the Golgi stain, which first produced pictures of neurons, was that it stained only a tiny fraction of the cells. That's why you can obtain a picture with cells reaching out and occasionally connecting. Whereas in reality all that empty space is other cells, doing the same thing. More modern pictures are like so: http://www.conte.harvard.edu/news/2015/8/18/imaging-the-brains-jungles-a-miniscule-yet-monumental-leap-forward http://www.conte.harvard.edu/news/2015/8/18/imaging-the-brai...