⑧ Paraffin embedding

Cool and solidify the tissue in paraffin.


  • Remove paraffin bath IV from the incubator and place it on a hotplate set to 70 °C.
  • Place the paraffin pouring dish (i.e., embedding dish) on the hotplate.
  • Prepare a device (e.g., alcohol lamp) to heat the tweezer tips used for tissue grasping.
  • Fill the embedding dish with paraffin.
  • For this process, use clean paraffin containing no intermediate solvent.
  • Always heat the tweezer tips before grasping the tissue.
  • Grasp the tissue after letting the heated tweezers slightly cool in the embedding dish paraffin.
  • Remove the tissue from paraffin bath IV, and place the tissue on the embedding dish with the cut side down.
  • Arrange the tissue with appropriate spaces between each tissue.
  • Transfer the embedding dish from the hotplate to the laboratory bench.
  • In order to achieve a flat surface for cutting press the tissue down gently with tweezers.
  • Embed a slip of paper containing the required information about the specimen (e.g., the tissue number) at the edge of the embedding dish.
  • Once the paraffin at the base of the embedding dish has turned slightly white and hardened, float the embedding dish in a tub filled with tap water.
  • Blow on the embedding dish. Once the paraffin on the embedding dish surface has hardened and formed a faint membrane, spray the embedding dish with tap water.
  • Once the paraffin on the surface of the embedding dish has further hardened and formed a skin, immerse the embedding dish in water.
  • Run weakly flowing tap water into the tub to harden the paraffin.
  • When the paraffin hardens and contracts it will separate from the embedding dish.