386 M. R. SMIRNOW 



ham, Herter, Penfold, Twort, Manfredi and others. The work 

 of the first of these investigators will be mentioned below, in 

 conjunction with the experiments of the writer. 



Herter (1910) has shown that sodium benzoate in weak glu- 

 cose broth considerably inhibits the fermentative activities 

 of B. coli, whereas other biological features are but shghtly 

 affected. Such action is entirely prevented by the addition 

 of calcium carbonate. He has also shown that there are no 

 gas producers in food stuffs preserved with sodium benzoate, 

 though 22 of 28 samples contained bacteria of some sort. Pen- 

 fold (1911) has shown similar action in the case of sodium ace- 

 tate on B. coli, B. enteritidis and B. paratyphi with diminishing 

 and total disappearance of gas formation in the sugars, though 

 the organisms were still capable of producing gas from the cor- 

 responding alcohols. This indicated an inhibition or destruc- 

 tion of the enzyme, invertase, without effect upon the gas pro- 

 ducing power. Twort (1907) has shown that B. typhi, B. para- 

 typhi and B. dysenteriae when continuously grown in saccha- 

 rose media will ultimately ferment saccharose. Manfredi (1889) 

 states that fat-containing media impair the vegetative energy 

 of bacteria. 



The observations here reported were undertaken in connection 

 with a series of experiments on the biological variations of bac- 

 teria, which the writer intends pubhshing in sections whenever 

 a sufficient amount of interesting material is accumulated to 

 warrant it. Twenty-one different strains of the various bacilli 

 of the colon-typhoid group were used, in the study but this 

 report is confined only to the B. coli, of which seven different 

 strains were experimented on. All of these strains were ob- 

 tained from the American Museum of Natural History, New 

 York, through the kindness of Prof. C.-E. A. Winslow, and 

 were the stock nos. 19, 44, 45, 46, 52, 57, and 95. The bacteria 

 were subjected to continuous growth at 37.5°C. in 3 per cent 

 glucose, 4 per cent sodium chloride and 1.5 per cent sodium sul- 

 phate broth. They were also grown in plain broth and then 

 exposed to he action of phenol in the following manner. The 

 culture was first inoculated into 9 cc. of plain nutrient broth 



