In a histology lab, an automated system immerses tissue samples mounted on microscope slides in multiple chemical stains. These stains make the tissues and cell structures more visible under a microscope. The standard or "routine stain" is the hematoxylin and eosin stain, better known as the "H&E" stain. With rare exceptions, every specimen being examined will first receive an H&E stain to give the pathologist a look at the nucleus of the cells and their present state of activity.