[Vol. 10 



40 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



additional data for comparison if need should arise. All 3 sugar 

 broths employed were found to have a buffer index of 1.5 where 

 "BI" is the sum of the reserve alkalinity and the reserve acidity, 

 each value being expressed in per cent normal alkali or acid. 



TABLE VII 



AND TITRATABLE 





Cultures 



Medium 



Controls 



1 day 



2 days 



5 days 



11 days 



Ph 



Titr. 

 acid. 



Ph 



Titr. 



acid. 



Ph 



Titr. 

 acid. 



Ph 



Titr. 

 acid. 



Ph 



Titr. 

 acid. 



Glucose 



Sucrose.. 

 Lactose 



6.0 



6.0 

 6.0 



+16 

 +16 

 +16 



5.4 

 6.4 

 5.6 



+20 

 +21 

 +20 



5.2 

 5.0 

 5.2 



+22 

 +24 

 +21 



5.0 

 5.0 

 5.2 



+25 

 +25 

 +25 



5.0 

 5.0 

 5.1 



Not determined 

 Not determined 

 Not determined 



From table vii it may be noted at a glance that (1) some acid 



developed by 



and (2) essentiallv equivalent amounts 



acid are developed in the presence of all 3 sugars employed. 



Attention is also directed to the fact that the major increase 

 in H-ion concentration took place during the first 2 days, and it 

 is believed (see Chambers, '20) that a true acidity of about -Ph 5 

 inhibits further growth and reproduction of the organism. 



SUMMARY OF COMPARATIVE STUDIES OF CAUSAL, ORGANISMS 



The salient characteristics of the several strains of the black- 

 l bacillus studied by the writer are brought together in com- 

 LCt form below. The scheme adopted is based upon the De- 

 riptive Chart indorsed by the American Society of Bacteriol- 

 ;ists in December, 1920. The digits used to designate the several 



and "secondary" characteristics of the strains in 

 l may be translated in detail by reference to the foregoing 

 d to the "brief characterization" column upon the de- 



"primary" 



above mentioned 



below indicate 



that there is verv little, if anv, difference between the 



beir 



ed by the writer, except No. 191, which aside from 



thoc-onin to t.lio notato. differs from the others in 



many nn 



