Abstract
Avery and Morgan 1 have recently demonstrated that fresh potato tissue, which was shown to contain a powerful peroxidase as well as certain food accessory substances, is able to promote the growth of pneumococcus in culture media. In these studies they noticed that a piece of potato when added to a broth culture of pneumococcus is able to abolish the lag period in the growth of this micro-organism, which enters, immediately after inoculation, into the logarithmic prase of growth.
In the author's experiments, the influence of tomato extract on the lag period in B. Shiga cultures was studied. It was found that this extract is able to shorten the lag period in cultures of this micro-organism if the original inoculum is sufficiently large.
The object of this investigation was to find an explanation of the mechanism of the shortening of the lag period by tomato extract. For this purpose a clear understanding of the function of the lag period in general is required. This seems to have been given by Sherman and Albus. 2 These authors believe that during the lag period the old cells of the inoculum undergo a biological rejuvenescence which fits them for reproduction. As a matter of fact, they showed that, just before the end of the lag period when no measureable increase in growth had as yet taken place, the inoculated old bacterial cells assumed certain characteristics which belong to young and actively multiplying bacteria.
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