STREPTOCOCCUS HEMOLYTICUS 



181 



Experiment VI. The influence of the amount of inoculum upon 

 the rate of acid formation in glucose broth 



Twenty cubic centimeters of 1 per cent glucose broth, Ph 

 7.10, were inoculated with varying amounts of an active, eighteen 

 hour culture of Streptococcus hemolyticus in 1 per cent glucose 

 broth and incubated. At two-hour intervals Ph determinations 

 were made on 1 cc. samples removed from. the cultures with 

 aseptic precautions. All cultures remained uncontaminated 

 throughout the entire period of the experiment. The results of 

 the experiment are to be found in table 5 and figure 3. 



TABLE 5 

 (Experiment VI) 



Reference to the curves (fig. 3) shows that the rates of acid 

 formation are at least roughly proportional to the quantities of 

 inoculum used. It is interesting to find that the hourly rate 

 (table 5) during the maximum period is least in the case of (5) 

 notwithstanding the fact that this contained the largest inoculum. 

 In other words, cultures (4), (3), and (2) though showing more 

 prolonged lag periods than (5), are able to proceed with acid 

 formation at more rapid rates, once the maximum period is 

 initated. No Ph determinations were made within the initial 

 two-hour interval, hence it is not possible to assume that any 

 of the cultures showed an entire absence of the stationary period. 

 In (4) and (5), however, the stationary period, if present, was 

 probably of very short duration. 



