30 
North Carolina Agricultural Experiment Station 
(15) and Streptococcus liemolyticus (12). Tlie investigations involving these 
two organisms explain this phenomenon on the basis of a selective action by 
the organism on the carbohydrate* radical of the protein molecule. After the 
carbohydrate is exhausted there is a reversal of reaction since the organism 
must then attack the protein for its supply of structural and fuel materials. 
Experiment IV—Changes in Hydrogen Ion Concentration in Plain 
Bouillon 
After determining the nature of the changes in reaction in beef extract 
broth and peptone broth, it seemed logical to employ plain bouillon in similar 
tests. Further, since this plain bouillon was to serve as a stock to which the 
carbohydrates were to be added in the fermentation tests to be next reported, 
it seemed desirable to know of the changes in reaction produced in plain bouil¬ 
lon alone. Accordingly, each of the organisms was cultured with the results 
summarized in Table 5. 
Table 5.—Changes in Reaction in Plain Bouillon, 1 Per Cent Peptone, 
0.3 Beef Extract, 0.5 NaCl. Initial pH 7.2 
Organism 
Age of Cultures in Days and pH Concentrations 
Days 
1 
2 
4 
6 
8 
10 
12 
pH 
pH 
pH 
pH 
pH 
pH 
pH 
Bacterium tabacum. -- -- 
7.2 
7.2 
7.4 
7.6 
8.2 
8.2 
8.4 
Bacterium angulatum- 
7.2 
7.2 
7.4 
7.6 
8.0 
8.2 
8.4 
Bacillus carotovorus - 
6.8 
6.6 
6.8 
7.4 
8.0 
8.2 
8.4 
Bacterium glycineum- 
7.2 
7.2 
7.4 
7.6 
8.0 
8.2 
8.4 
Bacterium sojae- 
7.2 
7.2 
7.4 
7.4 
7.8 
8.2 
8.4 
Bacterium campestre- - 
7.2 
7.2 
7.4 
7.8 
8.0 
8.2 
8.2 
All except B. carotovorus are seen to cause a progressive increase in alka¬ 
linity. This change proceeds until the point of inhibition by OH ions is ap¬ 
proximated. Whether or not other factors than concentration of hydroxyl ions 
influence inhibition is not known since no effort has been made to determine 
the presence or absence of such products of metabolism as are usually desig¬ 
nated “autotoxins.” In the case of B. carotovorus, there is at first, as pointed 
out in Table 4, an increase in acidity which is followed by a reversal of reac¬ 
tion and a gradual change toward the point of the OH limit of tolerance. 
*The occurrence of protein substances which contain a carbohydrate gioup 
has been known for a long time. The nature of this carbohydrate which can be 
split off by acid and which may amount to as much as 35 per cent in some pro¬ 
teins has been explained chiefly by the investigations of Friedrich Muller. 
(See Hammarsten and Hedin, Textbook of Physiological Chemistry, 7th edition, 
1914. p. 84). This carbohydrate is always an amino-sugar, and generally gluco¬ 
samine All proteins do not contain a carbohydrate group and future investi¬ 
gators must decide whether the carbohydrate groups belong positively to the 
protein complex or whether they are united with the proteins only as impuri¬ 
ties. 
