2. On the bottom of each dish draw two lines dividing the dish into 4 quadrants.
      Label the quadrants #1 through #4. (Remember to do all labeling backwards
           since the plate is upside down.)
      To one dish add the label; "Antiseptics", and your name.
      To the second dish add the label; "Antibiotics", and your name.

3. Carry the dishes to where the liquid agar is located and carefully pour agar
      in. (Remember to lift only one corner of the dish). Swirl the dishes to spread
      the agar evenly over the bottom. Allow 5 to 15 minutes for the agar to cool
      and solidify.

4. Once the dishes are solid carry them to where the E. coli culture is. Use a
      pipette to draw out .2 milliliter of culture. Lift one corner of the agar
      dish, and expel the culture onto the middle of the dish. Sterilize a
      bacterial spreader with alcohol and a flame, and use it to spread the
      E. coli culture evenly across the surface of your dish.

5. Once the bacteria is spread evenly, go to where the antiseptic disks are.
      The disks will be soaking in culture dishes filled with the desired antiseptic.
      Use the forceps provided to remove one disk from each dish and place it in
      the quadrant desired. (NOTE - The "Data Sheet" provides a place to list
      which antiseptics were placed in each quadrant.) It is often helpful to gently
      push each disk slightly into the agar using the appropriate forceps to assure
      that they will not fall off when the agar dish is inverted for incubation.

6. Carry the other agar dish to where the antibiotic disks are. These disks are
      located in plastic dispensers with their names on the sides. A disk should be
      removed from each dispenser and placed onto the desired quadrant. Some
      dispensers use an L-shaped arm to push the disk out, while others require
      a forceps to remove the disks.
      (NOTE – The "Data Sheet" provides a place to list which antibiotics were
      placed in each quadrant.) Again give each disk a gentle push with the
      forceps so that it is slightly embedded into the agar
.
7. Tape the two agar dishes together and place them in the incubator in an
      inverted position for 24 to 48 hours.

8. Obtain your incubated dishes and a small plastic ruler. Use the ruler to
      measure the DIAMETER of each zone of inhibition to the nearest millimeter,
      (NOTE - It is often much easier to measure the zone of inhibition through the
      bottom of the dish if it is well defined.) If the zone of inhibition is an incomplete
      or irregular circle, measure the "average" diameter. Record these Zones of
      Inhibition on the Data Sheet.

9. In the table for Antibiotics ONLY also indicate the sensitivity of each antibiotic for
      each bacteria. This can be done by comparing the Zone of Inhibition
      measured for each antibiotic and each bacteria with the chart provided in the
      Introduction to this lab.

10. When done with the plates dispose of them safely by spraying them with a bleach
      solution or by placing them in a container filled with a bleach solution.