It can be shown that what we breathe in and out is gas. You'd have a tougher job proving it's the "spirit."
Boy did YOU miss the point.. What is spirit or even Spirit?..
I mean what is it?.. Is it a substance, is it "thingly" ?..
Is "it" a personality, a him or her, or even an "it" ?...
Do you have a spirit?.. If so what is it?..