生物體各部活動能量的來源,是靠體內所燃燒養料的結果,而其養料所以能燃燒,有赖空氣中氧氣之參加:並把燃燒後產生的二氧化炭,排除體外。關於此種生物體內和外界環境间氣體交換過程,我們叫做呼吸。 The source of activity energy of each organism is the result of burning nutrients in the body, and its nutrients can burn, depending on the oxygen in the air to participate: and the combustion of carbon dioxide, excluding the body. We talk about breathing in the gas exchange process between this organism and the environment.