Light micrograph of a cross-section through the spinal cord, part of the central nervous system which carries motor and sensory information between the brain and the rest of the body. The central nervous system is composed of two different types of tissue; grey matter (consisting of neurone cell bodies, branching dendrites and glial cells) and white matter (consisting of tracts of nerve fibres). The spinal cord consists of a central butterfly-shaped region of grey matter (one brown-stained 'wing' of which is seen here) embedded within a layer of white matter (white). Magnification: x25 at 6x7cm size.