What is means by past consideration?

past consideration is of no effect to consideration at all. It is where the defendant's promise is subsequent to the plaintiff's act and independent of it. for example, where P saves D from drowning; Das an expression pf gratitude, later promises to pay P a sum of money as a reward. Here P cannot sue D on his promise since P's consideration is past in time, D's promise being subsequent abd independent of A's act. The case of Re McArddle illustrates the concept of past consideration