782 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 1.10 Sabouraud Liquid Medium Pancreatic digest of casein (Oxoid L42) 5 g Peptic digest of fresh meat (Oxoid L49) 5 g Dextrose 20 g Water to 1 000 ml Dissolve in a steamer and adjust pH to 5.7. Autoclave at 115 ø for 15 min. Commercial form: Oxoid Granules CM 147 or Tablets CM 148. 1.11 Malt Extract Agar Malt extract 30 g Mycological Peptone 5 g Agar 15 g Water to 1 000 ml (p}• 5.4) Add all the ingredients to the distilled water and heat in a steamer until dissolved. Distribute as required and sterilize at 121 ø for 15 min. In order to inhibit the growth of bacteria, the medium may be acidified to pH 3.5. This is done by adding a sterile 10% lactic acid solution (or a sterile 10% citric acid solution) to the liquefied medium immediately before pouring the plates. The exact amount of acid to be added to adjust the medium to pH 3.5 will depend upon the make or batch of constituents used. Commercial form: Oxoid Granules CM59 or Tablets CM60. 1.12 Malt Extract Broth Malt extract (Oxoid L39) 17 g Mycological Peptone (Oxoid L40) 3 g Water to 1 000 ml (pH 5.4 approx.) Prepare medium according to the manufacturer's directions. Commercial form: Oxoid Granules CM57 or Tablets CM58. 1.13 Salt Meat Broth Peptone (Oxoid L$7) Lab-Lemco beef extract Neutral ox-heart tissue 10 g 10 g 3O g

HYGIENIC MANUFACTURE AND PRESERVATION 783 Sodium chloride 100 g Water to 1 000 ml (pH 7.6 approx.) Commercial form: Oxoid Granules CM93 or Tablets CM94. 1.14 Selenite F. Broth The selenite in this medium serves the same purpose as tetrathionate in tetrathionate broth and has been preferred to it. Sodium acid selenite (NaHSeO 3) 4 g Peptone 5 g Lactose 4 g Disodium hydrogen phosphate (Na 2HPO 4.12H 20) 9.5 g Sodium dihydrogen phosphate (NaH2PO4.2H20) 0.5 g Sterile water 1 000 ml Dissolve the ingredients with aseptic precautions, and distribute the yellowish solution in 10 ml amounts in sterile screw-capped bottles, steam at 100 o for 30 min. Excessive heat is detrimental to the medium and auto- claving must not be used to sterilize it. A slight amount of red precipitate may form but this does not interfere with the properties of the medium. The pH of the medium should be 7.1 and the phosphates may be varied slightly if necessary to attain this. Salts of selenium are very toxic to animals and man, and must be handled xvith care. Some organic compounds of selenium and hydrogen selenide are volatile and toxic if inhaled. Commercial form: Oxoid Granules CM39 or Tablets CM40 (Modified). 1.15 Bacto-brilliant Green Agar. Difco Dehydrated Medium. Bacto-Yeast extract 3 g Proteose peptone no. 3, Difco 10 g Sodium chloride 5 g Bacto-lactose 10 g Saccharose, Difco 10 g Bacto-phenol red 0.08 g Bacto-brilliant green 0.0125 g Bacto-agar 20 g Bacto-Brilliant Green Agar is a selective medium recommended for the isolation of Salmonella, other than typhosa, either directly or after prelim- inary enrichment.