INGREDIENTS OF CULTURE MEDIA 259 



A typical quantitative analysis of Proteose Peptone, Difco is given on page 265. 



lAbst. Bact., 1:31:1917. 1^ J. Immunol., 22:283:1932. 



2 Abst. Bact., 2:10:1918. 18 J. Bact., 33:533: i937- 



8 Abst. Bact., 4:106:1919. 20 J, Immunol., 35:13:1938. 



* J. Med. Research, 36:357:1917. 21 Am. J. Pub. Health, 26:506:1936. 



^ J. Immunol., 13:323:1927. 22 j. Bact., 15:105:1928. 



« J. Bact., 23:195:1932. 23 J, Bact., 20:9:1930. 



'^ Brit. J. Exp. Path., 13:218:1932. ^Standard Methods for the Examination of 



8 Bayne- Jones : A Textbook of Bacteriology, Water and Sewage, 9th Edition: 230: 1946. 



1066:1934. 25 Pure Culture Study of Bacteria, 2:No. 4:1934. 



8 J. Immunol., 21:1:1931. 28 j, Bact., 23:135:1932. 



10 J, Infectious Diseases, 55:123:1934. 27 j, Bact., 29:223:1935. 



11 Biochem. J., 24:983:1930. 28 Brit. Med. J., 1:493:1948. 



12 J. Immunol., 20:71:1930. 29 Am. J. Pub. Health, 39:1314:1949- 

 ^ J. Infectious Diseases, 52:246:1933. ^ Am. J. Pub. Health, 40:704:1950. 

 "J. Immunol., 11:477:1926. si Am. J. CHn. Path., 21:282:1951 



15 Public Health Reports, 53:909:1938. ^^ J. Hygiene, 47:102:1949. 



i« J. Infectious Diseases, 41:9:1927. ^J. Bact., 62:137:1951. 

 "J. Exp. Med., 55:735:1932- 



PROTEOSE PEPTONE NO. 2, DIFCO (B121) 



The development of new peptones designed for specific purposes frequently 

 leads to their use in new fields of investigation. Thus, Proteose Peptone No. 2, 

 which is similar in type to Proteose Peptone, was originally developed in our 

 studies on peptones for use in production of diphtheria toxin. Although well 

 adapted for this purpose, it was never used extensively because Proteose Peptone, 

 either in a semi-synthetic medium or in a veal infusion base, became established 

 as a superior peptone in media used for diphtheria toxin production. 



Interest in Proteose Peptone No. 2 was revived by the work of Bunney and 

 Thomas^ in their study of diphtheria toxin production in semi-synthetic media. 

 These workers describe the preparation of a uniformly constant, infusion-free 

 medium composed of Proteose Peptone, Proteose Peptone No. 2, dextrose, maltose 

 and sodium acetate. This medium was reported as supporting a consistently good 

 yield of toxin. The work of Bunney and Thomas followed soon after that of 

 Marbe and Olariu^ who used Bacto-Peptone and Proteose Peptone for a similar 

 purpose. 



1 J. Immunol., 31:95:1936. 2 Compt. rend. soc. biol., 118:1673:1935. 



PROTEOSE PEPTONE NO. 3, DIFCO (B122) 



Investigating Proteose Peptone No. 2 for various purposes we developed an- 

 other modification of Proteose Peptone that proved to be excellent for the culti- 

 vation of many organisms. This peptone was designated as Proteose Peptone No. 

 3. Studies of the nutritive requirements of fastidious organisms have demonstrated 

 that a 2 per cent solution of Proteose Peptone No. 3 with 0.05 per cent dextrose 

 satisfactorily replaces the meat infusion-peptone portion of culture media. The 

 dextrose is added to supply a uniform amount of utilizable carbohydrate to 

 replace the variable amount of muscle sugars present in infusions from meat. 

 The use of Proteose Peptone No. 3 in this manner eliminates all of the laborious 

 processes of trimming, chopping and infusing meat. For example, a medium 

 superior to Douglas Agar enriched with whole blood as employed by Carpenter,^'^ 

 is prepared by mixing equal volumes of an autoclaved 2 per cent solution of 

 Bacto-Hemoglobin with an autoclaved agar medium composed of 4 per cent 

 Proteose Peptone No. 3, 0.1 per cent dextrose, 1 per cent sodium chloride, 1 per 

 cent disodium phosphate and 3 per cent agar. Chocolate Agar prepared according 



