[quote=@ADamnFiddle]
<Snipped quote by ConstantlyComic>

>Not just using chalk like a civilized hyuman bean 
[/quote]

You might've already figured this out, but Bailey, while he's not a total idiot, has a lot of dumb moments.
(Also, he's working with some pretty dated information, so he probably just thought that blood would be the easiest thing for him to use).