物质不灭定律又名物质守恒定律,是自然界最重要的定律之一。在任何与周围隔绝的物质系统(孤立系统)中不论发生何种变化或过程,其总质量始终保持不变。比利时的范·海尔孟(Van Helmont,1579～1644)在他的《医学入门》(Ortus Medicinae,1648)中写道当银或铜溶解在硝酸中,它并没有消灭,而是藏 The law of material immortality, also known as the law of conservation of matter, is one of the most important laws in nature. The total mass remains the same regardless of any changes or processes in any physical system isolated from the surroundings (orphaned systems). Van Helmont (1579-1644) of Belgium wrote in his book, Ortus Medicinae (1648) that when silver or copper was dissolved in nitric acid, it did not disappear,