Blue Blood

General Questions
#1

What’s the deal with the blue cast to veins that are visible underneath the skin? I think I know the answer to this already, but I want someone to explain because I have a follow-on question once someone gives a credible answer.

#2

For a credible answer, go the Archives and search on blood AND color … you will find the following Mailbag item on why veins appear to be blue:

http://www.straightdope.com/cgi-bin/ubbcgi/postings.cgi?action=reply&forum=General+Questions&number=3&topic=001243.ubb&TopicSubject=Blu e+Blood