any other use of the word IF?

[jasmineyue]

There is a sentense: And if, with the decay of vitality, weariness increases, the thought of rest will be not unwelcome.







Who can tell me what the word if in the sentence means???thank you very much.

 

[heidita]

Hi jasmine, it's a simple conditional sentence: if in the sense of

should weariness increase....