Sentence:  The evacuation of the rectum and bladder being completed, immediately the <WSD>nisus</WSD> ceases, the rectum and the sphincters return to their former state of contraction, the diaphragm reascends, carrying with it and restoring to their proper situations the liver, the stomach, the spleen, the small intestines, the cæcum, and the ascending, tranverse and descending portions of the colon. 
Meaning of the word marked with <WSD> tags:  A mental or physical effort to attain a specific goal; a striving.