"First off,there is the infectious disease risk because if you use human blood there's a lot of transmissible diseases.

VOA: special.2009.08.03

First, hopefully your blood clots and so that stops you from dying from loss of blood there, but your body tries to heal this wound that's created.

首先,顺利的话血液会形成凝块,使你不至于流血而死,进而身体尝试着去愈合创口

耶鲁公开课 - 生物医学工程探索课程节选

The first involves sheep. Researchers have found that hair sheep are a good source of blood for use in tests to diagnose infectious diseases in people.

VOA: special.2009.08.03