100 deg. C. (without
pressure) for twenty minutes on each of three successive days for all
fluid media, and thirty minutes on each of three successive days for all
liquefiable or solid media must be carried out; and only when these
general rules are to be departed from are further details given.

_Media for the Study of the Chemical Composition of Bacteria._

~Asparagin Medium (Uschinsky).~--

1. Weigh out and mix
Asparagin 3.4 grammes
Ammonium lactate 10.0 grammes
Sodium chloride 5.0 grammes
Magnesium sulphate 0.2 gramme
Calcium chloride 0.1 gramme
Acid potassium phosphate (KH_{2}PO_{4}) 1.0 gramme

2. Dissolve the mixture in distilled water 1000 c.c.

3. Add glycerine, 40 c.c.

4. Tube, and sterilise as for nutrient bouillon.

~Asparagin Medium (Frankel and Voges).~--

1. Weigh out and mix
Asparagin 4 grammes
Sodium phosphate, (Na_{2}HPO_{4}) 12OH 2 grammes
Ammonium lactate 6 grammes
Sodium chloride 5 grammes
and dissolve in
Distilled water 1000 c.c.

2. Tube, and sterilise as for nutrient bouillon.

NOTE.--Either of the above asparagin media, after the
addition of 10 per cent. gelatine or 1.5 per cent. agar, may
be advantageously employed in the solid condition.

~Proteid Free Broth (Uschinsky).~--

1. Weigh out and mix
Calcium chloride 0.1 gramme
Magnesium sulphate 0.2 gramme
Acid potassium phosphate (KH_{2}PO_{4}) 2.0 grammes
Potassium aspartate 3.0 grammes
Sodium chloride 5.0 grammes
Ammonium lactate 6.0 grammes

2. Dissolve the mixture in distilled water 1000 c.c.

3. Add glycerine 30 c.c.

4. Tube and sterilise as for nutrient broth.

_Media for the Study of Biochemical Reaction._

~Inosite-free Media--Bouillon (Durham).~--

1. Prepare meat extract, 1000 c.c. (_vide_ page 148), from bullock's
heart which has been "hung" for a couple of days.

2. Prepare nutrient bouillon (+10), 1000 c.c. (_vide_, page 161), from
the meat extract, and store in 1-litre flask.

3. Inoculate the bouillon from a pure cultivation of the B. lactis
aerogene