The blood smear is stained with Wright's stain, allowing students to easily distinguish between red and white blood cells. Erythrocytes (red blood cells) are the plentiful, pink cells in the smear. Leukocytes (white blood cells) are larger cells with a purple nucleus. Based on the shape and size of the nucleus in the white blood cells, students can classify them as neutrophils, eosinophils, basophils, lymphocytes, or monocytes. In addition, students can identify platelets in the smear; these are also pink cells but are much smaller than the numerous red blood cells.