Abstract
The synthetic media described in our earlier papers1,2 have been used for testing the value of various substances as nutrients. The studies in this paper are concerned with the effect on the growth and viability of streptococci, of the addition of various carbon compounds to the media. These compounds include dextrose, galactose, mannite, lactose, maltose, sucrose, raffinose, glycerol, lactic, tartaric, malic and citric acids.
The experiments show: (1) In most cases dextrose shortens the period of viability markedly. Apparent increases in viability due to the addition of dextrose have been obtained but they were too small to be taken into account. (2) A comparison of dextrose with other sugars in reference to their availability for growth gives series such as sucrose > lactose, maltose > raffinose > mannite, dextrose.
There are several references in the literature to the growth value of dextrose. Samkow 3 and Waksman and Joffe 4 found that although dextrose did no harm, it did not aid materially. Frankel and Pyle 5 showed that dextrose retarded growth slightly. Koser and Rettger 6 reported glycerol better for growth than dextrose because less acid is formed and the organism is therefore “freer to develop”. None of these investigations refer specifically to the streptococci.
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