Leeches
The word leech is derived from the Old English word “laece,” or doctor, and Syrian physicians reportedly first used leeches for bleeding as early as 100 B.C. This was a painless and efficient way of drawing blood since the leech excretes several hormones including one to anesthetize the bite, one to dilate vessels to insure flow, and a third, hirudin, to act as an anticoagulant.