Annals 
Missouri Botanical Garden 
Vol. 7 NOVEMBER, 1920 No. 4 
STUDIES IN THE PHYSIOLOGY OF THE FUNGI 
XI. BACTERIAL INHIBITION BY METABOLIC Propucts 
WILLIAM H. CHAMBERS +. 
Formerly Rufus J. Lackland Fellow in the Henry Shaw School of Botany of 
Washington University 
Considerable work has been done on the early phases of 
growth of bacteria in liquid media. Rahn (’06), Coplans (707), 
Penfold (14), Chesney (716), Salter (19), and others have 
shown quite definitely the factors involved in the lag phase 
of growth preceding the phase of logarithmic increase. They 
have demonstrated that the lag can be eliminated if the trans- 
fers are made during the period of logarithmie increase, but 
that certain factors such as difference in temperature, composi- 
tion of the medium, or the age of the culture will produce a 
latent period immediately following the transfer. 
Data on the later growth periods of bacteria are less extensive. 
Based on the total number of viable bacteria in the culture, the 
growth curve can be traced roughly as follows: It rises abruptly 
at first, which is the phase of logarithmic increase, then ascends 
more gradually until the peak is reached, and finally descends 
until the culture is sterile. The influence of inhibitory factors 
is most clearly seen in the later periods, those following the phase 
of logarithmie inerease, the study of which is of fundamental 
and practical importance both in killing pathogenic bacteria, 
that is, hastening the decline in the growth curve, and in pro- 
longing the life of useful cultures, suspending this decline. In 
the work presented here, emphasis is placed on the later periods 
of growth and on the influence of the products of a growing cul- 
ture on the path of the growth curve. 
ANN. Mo. Bor. Garp., Vor. 7, 1920 (249) 
