I just want to step in here for a moment to say how glad I am for having started this thread, because it has turned out to be so informative. And another reason is that, by means of links that have been posted, I learned about these two other very informative threads that deal with this same subject--both of which were started by Cofty.
I want to express a hearty thanks to Cofty for posting (sharing) the results of the research you have done. It is apparent that you devoted a lot of time, thought, and effort in pursuit of an accurate understanding of the blood issue.
I also want to thank all of you others who are participating in this thread, for sharing your thoughts and knowledge.