[Vor. 7 
250 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
LITERATURE 
The literature on the subject of the inhibition of bacteria in 
culture by their own metabolic products is widely scattered, 
and the investigational work in this phase of growth studies 
is very meager. The entire subject is often dismissed with 
some such statement as “the organisms are finally killed by 
their own products.” 
From time to time different investigators have sought to 
determine if there is a special metabolic product, enzymatic in 
nature, which inhibits the growth of the organism producing 
it. One of the earliest publications on this subject appeared by 
Eijkmann (004) He grew Bacillus coli in gelatin at 37° C., 
treated it in different ways, and then solidified and reinoculated 
the gelatin. He concluded that Bacillus coli in gelatin pro- 
duced a diffusible, thermolabile substance which would not pass 
through a porcelain filter and which inhibited growth of Bacillus 
coli and other organisms, for treatment with ether, subjection 
to heat, or filtration through a porcelain filter removed some 
inhibiting substance and permitted a streak growth on the 
solidified gelatin. 
The following year Conradi and Kurpjuweit ('05,'05*) extended 
the work of Eijkmann, finding the same action in bouillon. 
They called the substance “autotoxin” and applied the theory 
to the germicidal action found in feces. "They reported that 
the “autotoxin” of Bacillus coli was killed by boiling but was 
virulent up to a dilution of 1:3200 in a 10-hour culture, and 
that the heated stool filtrate from a paratyphoid patient would 
support growth of the same Bacillus paratyphosis in a 1:50 dilu- 
tion, but the unheated filtrate only in a 1:400 dilution. Rolly 
(06), Passini (06), and Manteufel ('07) disputed the findings 
of Eijkmann, also those of Conradi and Kurpjuweit, and held 
that the existence of inhibitory substances had not yet been 
proved. Rolly could not repeat the work of Conradi and Kurp- 
juweit with the same results but found that the filtered half 
of a 20-hour bouillon culture gave better growth than the cooked 
half. Manteufel claimed that the loss of necessary food ma- 
terial from the media explained some of the results attributed 
to “autotoxin.” Kruse (10) summarized these reports and 
