The central portion comprises the brain or encephalon and the spinal cord.
"Common Diseases of Farm Animals"
R. A. Craig, D. V. M.
The physiological experimenter has also made it evident that the decussation of the conductors of sensitive impressions has its seat in the spinal core, and not in the encephalon, as had been supposed.
"The Complete PG Works of Oliver Wendell Holmes, Sr."
Oliver Wendell Holmes, Sr. (The Physician and Poet not the Jurist)