Origin of "Grasping/Clutching at Straw"

Factual Questions
1

I’ve googled, word detectived, and SDMB searched.

Isn’t there an entire sentence that this phrase comes from?

Whence this saying?

2

First off, the entire sentence reads: “A drowning man will clutch at straws.” Originally from Thomas More. The desperation is a little more apparent when you get the whole picture.

3

Sorry. Forgot to note:
Thomas More’s book is “Dialogue of Comfort Against Tribulation” (1534)