Recording the fine property happening inside neuron. Want to develop hypothesis and test it by manipulating system. Observe what is happening in undisturbed system. And after manipulation want to see what type of consequences you generate can do in human. To test hypothesis you manipulate system and animal. And the layers and nuclei what do all the strucutures look like and how components connected with each other. Without staining see big mess not tell you anything of fine strcuutrue need to prepare tissue with stain and key to understanding the strucuture of neurons and brain and gernal is how you treat specimen. Use to visualize cells and connectivity in different levels. Method by german neurologists francis nissl in late 1980s and basically a die use blue or violet and incubate tissue in die solution penetrate ans stain cell body. Also look in middle see cluster in middle. Golgi by neuranatomist staining method two chem.