Nutrient agar 1000 c.c.

2. Weigh out: lactose 10 grammes and dissolve in the fluid agar.

3. Adjust the reaction to -5 and filter.

4. Measure out and mix thoroughly with agar:

Fuchsin, alcoholic solution 5 c.c.

The fuchsin solution is prepared by mixing:

Fuchsin (basic) 3 grammes.

Absolute alcohol 60 c.c.

Allow to stand twenty-four hours, then centrifugalise thoroughly and decant the supernatant fluid into a well-stoppered bottle.

5. Measure out and add to the nutrient agar, sodium sulphite, 10 per cent. aqueous solution, freshly prepared 25 c.c.

6. Tube and sterilise as for nutrient agar.

7. Store in a dark cupboard.

~Fuchsin Sulphite Agar (Endo).~--

1. Liquefy and measure out into a sterile flask:

Nutrient agar 1000 c.c.

2. Weigh out

Lactose 10 grammes.

and dissolve in the fluid agar.

3. Adjust the reaction to +3 and filter.

4. Measure out and mix thoroughly with the fluid agar.

Fuchsin, alcoholic solution (_vide supra_) 5 c.c.

5. Measure out and add to the medium

Sodium sulphite, 10 per cent. aqueous solution 25 c.c.

6. Tube and sterilise as for nutrient agar.

~Brilliant Green Agar (Conradi).~--

1. Liquefy and measure out into a sterile flask

Nutrient agar 1000 c.c.

2. Adjust reaction to +30 by the addition of normal phosphoric acid; and filter.

3. Measure out and mix thoroughly with the fluid medium

Brilliant green (Hoechst) 1 per thousand aqueous solution 6.5 c.c.

4. Measure out and add to the medium

Picric acid (Gruebler), 1 per cent. aqueous solution 6.5 c.c.

5. Tube and sterilise as for nutrient agar.

~Brilliant Green Bile Salt Agar (Fawcus).~--

1. Weigh out agar 20 grammes and emulsify in 100 c.c. cold distilled water.

2. Wash the emulsion into a "tared" 2-litre flask with 500 c.c.

distilled water.

3. Dissolve the agar by bubbling live steam through the flask.

4. Cool, clarify with egg and filter.

5. Weigh out

Sodium taurocholate 5 grammes Peptone 20 grammes

and add to the medium in the flask.

6. Weigh out

Lactose 5 grammes

and add to the medium in the flask.

7. Adjust reaction to +15 and filter if necessary.

8. Measure out

Brilliant green, 1 per thousand aqueous solution 20 c.c.

and mix thoroughly with the fluid agar.