Preparing the bone marrow smear. (A) When the bone marrow aspiration needle is in place, use a 20 ml syringe to draw 1 ml of aspirate. (B) Place a few drops of aspirate on a slide held vertically to facilitate visualisation of the bone marrow spicules. (C) Using the edge of a second slide, separate and isolate a few bone marrow spicules from the rest of the sample. (D) Transfer these to a third slide. (E) Without applying pressure, distribute the spicules in the centre of the slide. (F) Place the second slide across the third slide to form a cross with the spicules in the centre. (G) Gently but quickly slide the second slide over the third slide to extend the spicules along its length. (H) Make sure the aspirate is spread evenly over the entire slide. (I) Allow to dry for 5 min, and then send it to the lab for tincture.