Kill a normal guinea-pig with chloroform vapour.

Open the thorax with all aseptic precautions, and collect as
much blood as possible from the heart with a sterile Pasteur
pipette.

Transfer it to a sterile centrifuge tube and place the tube
in the incubator at 37 deg. C. Two hours later separate the clot
from the sides of the tube, and centrifugalise thoroughly.

Pipette off the clear serum to a clean sterilised test-tube.

4. Erythrocyte solution, in test-tube labelled E.

Collect and wash human red blood cells (see page 388, 1-8).
Measure the volume of red cells available and prepare a 2
per cent. suspension in normal saline solution.

METHOD.--

1. Take two test-tubes and number them 1 and 2, and pipette into each 9
c.c. of normal saline solution.

2. Add 1 c.c. of haemolytic rabbit serum to tube No. 1 and mix
thoroughly: take up 1 c.c. of the mixture and add it to tube No. 2; mix
thoroughly.

3. Set up ten small test-tubes in test-tube rack or in roll of
plasticine, and number 1 to 10.

4. Pipette into tube No. 1 0.5 c.c. = 0.5 c.c.}
haemolytic serum } From tube
Pipette into tube No. 2 0.1 c.c. = 0.1 c.c. } H. S.
haemolytic serum }

Pipette into tube No. 3 0.5 c.c. = 0.05 c.c. }
haemolytic serum }
Pipette into tube No. 4 0.3 c.c. = 0.03 c.c. }
haemolytic serum } From
Pipette into tube No. 5 0.2 c.c. = 0.02 c.c. } tube 1.
haemolytic serum }
pipette into tube No. 6 0.1 c.c. = 0.01 c.c. }
haemolytic serum }

Pipette into tube No. 7 0.5 c.c. = 0.005 c.c. }
haemolytic serum }
Pipette into tube No. 8 0.3 c.c. = 0.003 c.c. }
haemolytic serum } From
Pipette into tube No. 9 0.2 c.c. = 0.002 c.c. } tube 2.
haemolytic serum }
Pipette into tube No. 10 0.1 c.c. = 0.001 c.c. }
haemolytic serum }

5. To each tube add 1 c.c. of erythrocyte solution.

6. When necessary (that is to say in tubes 2, 4, 5, 6, 8, 9 and 10) add
normal saline solution to the mixture in the test-tubes till the column
of fluid in each reaches to the same level.

7. Shake each tube in turn, so