.

4. Filter through Swedish filter paper into a sterile flask.

5. Add sterile litmus solution sufficient to colour the
medium to a deep purple, usually 13 per cent. required.

6. Fill, in quantities of 10 c.c., into tubes containing
small gas tubes (_vide_ Fig. 104, page 161). Sterilise in
the steamer at 100 deg. C. for twenty minutes on each of three
consecutive days.

~Glucose Formate Bouillon (Kitasato).~--

1. Measure out nutrient bouillon, 1000 c.c. (_vide_ page
163, sections 1 to 6).

2. Weigh out glucose, 20 grammes (= 2 per cent.), sodium
formate, 4 grammes (= 0.4 per cent.), and dissolve in the
fluid.

3. Tube, and sterilise as for bouillon.

~Glucose Formate Gelatine (Kitasato).~--

1. Prepare nutrient gelatine (_vide_ page 164, sections 1 to
7) and measure out 1000 c.c.

2. Weigh out glucose, 20 grammes (= 2 per cent.), and sodium
formate, 4 grammes (= 0.4 per cent.), and dissolve in the
hot gelatine.

3. Filter through papier Chardin.

4. Tube, and sterilise as for nutrient gelatine.

~Glucose Formate Agar (Kitasato).~--

1. Prepare nutrient agar (_vide_ page 167, sections 1 to 8).
Measure out 1000 c.c.

2. Weigh out glucose, 20 grammes (= 2 per cent.), sodium
formate, 4 grammes (= 0.4 per cent.), and dissolve in the
agar.

3. Tube, and sterilise as for nutrient agar.

~Sulphindigotate Bouillon (Weyl).~--

1. Measure out nutrient bouillon (_vide_ page 163, sections
1 to 6 1000 c.c.).

2. Weigh out glucose, 20 grammes (= 2 per cent.), sodium
sulphindigotate, 1 gramme (= 0.1 per cent.), and dissolve in
the fluid.

3. Tube, and sterilise as for bouillon.

~Sulphindigotate Gelatine (Weyl).~--

1. Prepare nutrient gelatine (_vide_ page 164, sections 1 to
7). Measure out 1000 c.c.

2. Weigh out glucose, 20 grammes (= 2 per cent.), and sodium
sulphindigotate, 1 gramme (= 0.1 per cent.), and dissolve in
the hot gelatine.

3. Filter through papier Chardin.

4. Tube, and sterilise as for nutrient gelatine.

~Sulphindigotate Agar.~--

1. Prepare nutrient agar (_vide_ page 167, sections 1 to 8).
Measure out 1000 c.c.

2. Weigh out glucose, 20 grammes (= 2 per cent.), sodium
sulphindigotate, 1 gramme (= 0.1 per cent.), and dissolve in