was prepared by the author in partial fulfillment of the requirements for qualification as a Submarine Medical Officer. It has been selected by the Board of Examiners for publication at this time, in order to make the information available as reference material in the School of Submarine Medicine, and in the Technical Library, Submarine Medical Center, as well as to all qualified Submarine Medical Officers serving throughout the Submarine Force. It has been designated as Submarine Medical Research Laboratory Report No. 582. This document has been approved for'public release and sale; its distribution is unlimited.