I think the concept of staining is a powerful idea. On the left you see a photograph of a silver chromate stained piece of the cerebellum. The staining process was developed by Golgi. As most of you probably know, the key to the Golgi staining process is that it randomly stains cells. If all the cells were stained, this would not be a useful picture.
Golgi believed that neurons were all directly interconnected in a single large web.?The competing theory was due to Cajal, who believed that neurons were individual components connected through synapses.?Cajal proved his theory through years of careful observation. Cajal and Golgi were bitter rivals and it must have annoyed Golgi to no end that Cajal used Golgi?s staining technique to prove his theory. Fortunately, they both shared the Nobel Prize in 1906.
On the right is a drawing by Cajal. Note his beautiful depictions of the bushy Purkinje cells on the top and the interconnecting granular cells on the bottom. Cajal had amazing skills of observation. Careful observers are often great illustrators.
Reference:
[1] http://cti.itc.virginia.edu/~psyc220/
[2] http://www.psu.edu/nasa/cajal2.htm