.

Take 1½ grams of dried lettuce to 1 litre of distilled water.

Method

Boil 4½ grams of lettuce in 2 litres of distilled water, strain and allow to cool. When cool add the other litre and 5 grains of rice for each 200cc of water, i.e. 25 grains per litre - 75 grains for the three litres. This will feed the bacteria that the protozoa will in turn feed off. The infusion can either be seeded immediately with protazoa culture or left to stand for a few days in an open-topped container with a net over it. The culture will than live for 2 weeks before dying off. The advantage of this culture is that there is no smell.

EUGLENA

The protazoa Euglena is for feeding small delicate fry

For culturing Euglena bring about ½pint of water to the boil in a saucepan and place 4 grams (62grains) of wheat in it. Continue to boil briskly for approx 10mins and then drain off the water. Place the wheat grains in clean sterilized (by boiling) chemical flask, or a pint bottle. Now place about 3½fluid ozs of water straight from the cold tap, into this bottle and cork it with a wad of cotton wool. Keep the bottle in a dark place for about 2 weeks. Shake the contents daily to break up the scum, which forms on the surface of the fluid, but do not wet the bung. Occasionally lift the cotton wool bung out for a few seconds and replace it again. At the end of the 2 weeks the culture medium is ready and must be seeded with euglena.

The organisms can be obtained from the biology department of the University.

Place in a fairly warm bright spot 50-70 deg not in direct sunlight. After about one month the culture should be quite thick and a single drop may contain 250,000 or more individuals. If wheat is difficult to obtain then rice one quarter the quantity or barley may be used but the result with this is very unreliable