562 



J. HOWARD BROWN 



TABLE 1— Continued 



The buffer index, reserve acidity and reserve alkalinity are expressed in terms 

 of per cent normal alkali or acid. Note that the buffer index equals the reserve 

 acidity plus the reserve alkalinity. 



results tabulated in table 1. Each sample represents a different 

 lot of bouillon. The buffer indices of the samples of plain meat 

 infusion bouillon varied from 1.7 to 5.95. Samples from our 

 own laboratory (A) , made at different times but under supposedly- 

 uniform conditions, varied from BI 3.45 to 5.25. Of the two 

 samples from laboratory D one had a buffer index of 1.7 and the 

 other 3.5. Four lots of bouillon, A8a, A8b, A8c and ASd were 

 made from the same veal infusion but with different brands 

 of pepton. Their buffer indices were fairly uniform but not 

 very high. Somewhat less variation was shown by the samples 

 of fermented bouillon titrated. Samples of bouillon made 

 from Liebig' s beef extract had low buffer indices except sample 

 C3 which titrated BI (pH 8 - 5) = 4.25. This sample was 

 found contaminated by a mixed culture when received. The 

 lowest index was that of sample A20, made of Bacto Nutrient 

 Broth (dehydrated) according to the manufacturer's directions 

 printed on the bottle. 



The association of contamination with the high buffer index of 

 extract bouillon C3 suggested that the growth of the culture 

 might have altered the buffer index. Two samples of bouillon 



