INGREDIENTS OF CULTURE MEDIA 265 



secondary proteoses are available Bacto-Protone forms the nearest and most 

 useful substitute. 



Being low in readily utilizable nitrogen Bacto-Protone does not, by itself, 

 support good growth of bacteria. Its usefulness lies in combination with more 

 readily available forms of nitrogen. W. E. Bunney has suggested its use as a 

 diluent for maintaining the potency of diluted diphtheria toxin for use in the 

 Schick test. Studies undertaken by the New York State Health Department^ 

 indicate that marked stability of the toxin dilutions was secured when Bacto- 

 Protone was used. 



A typical quantitative analysis of Bacto-Protone is given below. 



IN. Y. State Health Dept., 54th Annual Report: 72: 1933. 



Typical Analyses of Peptones 



Peptone , c 



S2 



u O. 



Per Cent 



Total Nitrogen 16.16 



Primary Proteose N . . 0.06 



Secondary Proteose N 0.68 



Peptone N 15.38 



Ammonia N 0.04 



Free Amino N (Van 



Slyke) 3.20 



Amide N 0.49 



Mono-amino N 9.42 



Di-amino N 4.07 



Tryptophane 0.29 



Tyrosine 0.98 



Cystine (Sullivan) . . . 0.22 



Organic Sulfur 0.33 



Inorganic Sulfur 0.29 



Phosphorus 0.22 



Chlorine 0.27 



Sodium 1.08 



Potassium 0.22 



Calcium 0.058 



Magnesium 0.056 



Manganese nil 



Iron 0.0033 



Ash 3.53 



Ether Soluble Extract 0.37 



Reaction, pH 7.0 



pH I per cent solution in dis- 

 tilled water after autoclaving 15 

 minutes at 121 oC. 



HYDROLYSATES, ACID 



BAGTO-G AS AMINO AGIDS (B230) 



Bacto-Casamino Acids is acid hydrolyzed casein recommended for use in the 

 production of diphtherial toxin and other biological products. Hydrolysis is car- 



