:That's a trick question, right? They're too small to see. P Actually, if you centrifuge a tube of blood, you'll see a thick layer of red cells at the bottom and yellow plasma on top. In between, there's a small white layer, which is where the white blood cells reside and why they're called "white". Similarly, pus (which is made up largely of dead white blood cells) is white(-ish). So maybe they are white - if you clump a lot of them together, they certainly look that way. When you view them under a microscope, they look more or less clear/transparent, unless of course they've been stained. ''''''