This hematoxylin ­ eosin ­ stained preparation is also from the spinal cord. You should be able to pick out the large neurons with their Nissl bodies and the tiny nuclei of the supporting cells. The vacuoles around the neurons are tissue shrinkage artifacts, which are indicative of poor tissue fixation. The matrix around the somas is made up of delicate parts of neurons (dendrites, axons and synaptic endings) and supporting cells that can only be resolved by the electron microscope. This matrix is often referred to as the neuropil. Running through it are some long pale streaks that represent the dendrites and myelinated axons of the large neurons. Since they contain only a little nucleoprotein, they do not stain very intensely with the basic dye, which in this case is hematoxylin.