"i: 



INGREDIENTS OF CULTURE MEDIA 257 



In a study by Morton, Smith and Leberman*^ Bacto-Peptone was reported to 

 be superior to other peptones in a medium recommended for the isolation and 

 cultivation of pleuropneumonia-like organisms. 



This list is by no means complete or exhaustive but it suffices to indicate the 

 wide range of usefulness of Bacto-Peptone. In addition to the references men- 

 tioned many other citations are to be found in the literature. 



Bacto-Peptone contains nitrogen in a form which is readily available for bac- 

 terial growth requirements. It has a high peptone and amino acid content and 

 only a negligible quantity of proteoses and more complex nitrogenous constituents. 

 Bacto-Peptone is completely soluble in water and yields sparklingly clear solu- 

 tions in the concentrations usually employed for culture media. From the very 

 first, Bacto-Peptone has been standardized to a definite hydrogen ion concentra- 

 tion of pH 7.0 in a one per cent solution, as generally employed in culture media. 



A typical quantitative analysis of Bacto-Peptone is given on page 265. 



1 Standard Methods for the Examination of 22 Sixth Annual Year Book (1935-1936) p. 159. 

 Water and Sewage, 9th Edition: 184: 1946. Suppl., Am. J. Pub. HeaUh, 26: No. 3:1936. 



2 Bull. 524, N. Y. Agr. Exp. Sta., 1924. ^^ J. Infectious Diseases, 63:122:1938. 



3 J. Dairy Science, 16:277:1933. ^ J. Infectious Diseases, 62:138:1938. 

 * Standard Methods, Div. Labs. Res. N. Y. 25 j_ Path. Bact., 39:323:1934. 



Dept. Health, 1927. 26 Am. J. Pub. Health 28:759:1938. 



^ Compt. rend. soc. biol., 118:1673:1935. ^^ Proc. Soc. Exp. Biol. Med., 26:88:1928-29. 



^ Public Health Reports, 53:909:1938. 28 j Bact., 20:85:1930. 



' J. Infectious Diseases, 24:260:1919. 29 j, Immunol., 18:141:1930. 



^ J. Infectious Diseases, 28:384:1921. so j_ Infectious Diseases, 54:35:1934. 



^ J. Bact., II :359: 1926. ^Phytopathology, 24:1153:1934. 



10 Abst. Bact., 6:34:1922. S2 Sixth Annual Year Book (1935-1936) p. 118. 

 Bact., 29:349:1935. Suppl. Am. J. Pub. Health, 26:No. 3:1936. 



Bact., 32:329:1936. 83 Sixth Annual Year Book (1935-1936) p. 193. 

 J. Infectious Diseases, 58:225:1936. Suppl., Am. J. Pub. Health, 26:No. 3:1936. 



^* J. Am. Water Works Assoc, 30:808:1938. ^ J. Infectious Diseases, 15:417:1914. 



1^ J. Am. Water Works Assoc, 30:1821:1938. ^5 ^.m. J. Pub. Health, 14:1043:1924. 



"J. Bact., 7:449:1922. 3«J. Gen. Physiol., 8:89:1925. 



1'^ J. Infectious Diseases, 39:186:1926. ^ J. Bact., 19:261:1930. 



^^ J. Lab. Clin. Med., 17:530:1931-32. ^ J. Bact., 9:235:1924. 



^^ J. Lab. Clin. Med., 15:662:1929-30. 89 BJochem. J., 30:1323:1936. 



""^ J. Exp. Med., 50:617:1929. ^ J. Bact., 32:533:1936. 



"1 J. Bact., 25:527:1938. *i Am. J. Syphilis Gonorrh. Venereal Diseases, 



35:361:1951. 



PROTEOSE PEPTONE, DIFGO (B120) 



Proteose Peptone is particularly adapted for use in culture media for the 

 production of various bacterial toxins. This peptone is the result of extensive 

 investigations which had their inception in the fact, developed by practical ex- 

 perience, that no one peptone was equally useful for all the varied phenomena 

 included in the biological and biochemical reactions produced by bacteria. As an 

 illustration of this fact the work carried out on the production of diphtheria toxin 

 may be cited. Excellent, and indeed luxuriant, growth of Corynebacterium 

 diphtheriae may be obtained in the usual Veal Infusion Medium containing 

 Bacto-Peptone, but toxin production is exceedingly slight. Accordingly, over a 

 period of six years the full time of bacteriologists and chemists in our laboratoriei 

 was devoted to a study of all phases of diphtheria toxin production before Pro 

 teose Peptone was selected as the most satisfactory peptone for this purpose. 



While the exact chemical composition of diphtheria toxin is still unknowi\ 

 many factors influencing its production have been established. During the early 

 work on the development of Proteose Peptone and while studying the production 

 of diphtheria toxin, Bunker^'^.s recognized the importance of a correctly buffered 

 peptone, the necessity of the optimum initial reaction of the toxin broth, and the 

 limiting hydrogen ion concentration within which potent toxin could be harvested 



