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