Olfaction is to know the smell of the patient's body, the secretion and excreta by means of osphresis (smelling).听声音是凭听觉以诊察病人的语言、呼吸、咳嗽等声音的异常；嗅气味是凭嗅觉诊察病人体内产生的气味，以及分泌物、排泄物的气味变化。