in the center of the next ward , a tall , gangly man in a dark frock coat was carrying out what appeared to be the skillful amputation of a leg ; particularly skillful in that the patient was not sedated in any visible way , and was being restrained at the moment by the efforts of two husky orderlies and a solidly built nun who was sitting upon the patient 's chest , her flowing draperies fortunately obscuring the man 's face .