Spinal cord. Mallory stain. Meninges (in right upper corner), white matter and grey matter. The strands of collagen fibers from the pia into the white matter accompany thin walled (collapsed) blood vessels. Note the extracted myelin "doughnuts" around axon cross sections in the white matter and the different sized multipolar perikarya of the grey matter. Red blobs are stain artifact. What is the neuropil composed of? ANSWER: Cell processes, glia and blood vessels.