ll cylinder containing 2 per cent. lysol solution.
Bunsen burner.
Grease pencil.
Water-bath regulated at 42 deg. C.

METHOD.--

1. Arrange the plate-levelling platform with its water compartment
filled with water, at 45 deg. C.

2. Number the agar tubes, consecutively, 1 to 6; the gelatine tubes,
consecutively, 1 to 6, and the wort tubes, 1, 2, and 3. Flame the plugs
and see that they are not adherent to the lips of the tubes.

3. Place the agar tubes in boiling water until the medium is melted,
then transfer them to the water-bath regulated at 42 deg. C. Liquefy the
nutrient gelatine and wort gelatine tubes by immersing them in the same
water-bath.

4. Remove the bottle containing the water sample from the ice-box,
distribute the bacterial contents evenly throughout the water by
shaking, cut the string securing the stopper, and loosen the stopper,
but do not take it out.

[Illustration: FIG. 206.--Withdrawing water from water sample bottle.]

5. Remove one of the 1 c.c. pipettes from the case, holding it by the
plain portion of the tube. Pass the graduated portion twice through the
Bunsen flame. Tilt the bottle containing the water sample on the bench
holding the neck between the middle and ring fingers of the left hand;
grasp the head of the stopper between the forefinger and thumb, and
remove it from the bottle.

6. Pass the pipette into the mouth of the bottle, holding its point well
below the surface of the water (Fig. 206). Suck up rather more than 1
c.c. into the pipette and allow the pipette to empty; this moistens the
interior of the pipette and renders accurate measurement possible. Now
draw up exactly 1 c.c. into the pipette. Withdraw the pipette from the
bottle, replace the stopper, and stand the bottle upright.

7. Take the first melted agar tube in the left hand, remove the
cotton-wool plug, and add to its contents 0.5 c.c. of the water sample
from the pipette; replug the tube and replace it in the water-bath. In a
similar manner add 0.3 c.c. water to the contents of the second tube,
and 0.2 c.c. to the contents of the third.

8. In a similar manner add 1 c.c. of the sample to the contents of the
fourth tube.

9. Similarly, add 0.5 c.c. and 0.1 c.c. respectively to the contents of
the fifth and sixth tubes.

10. Drop the pipette into the cylinder containing lysol solution.

11. Mix the water sample with the medium in each tube in the manner
described under plate cultivations;