/l/ According to E. G. Pringsheim, the organism used in these studies was E. geniculate. /2/ According to E. G. Pring- 

 sheim, the organism used in these studies was E. mutabilis. /3/ Syn. A. chattoni (A. Lwoff, 1936) or A. klebsii (H. von 

 Dach, 19*^0). /l^/ The average range of concentration in mg, per 100 ml of media, at which fatty acids are utilized and 

 non-toxic is the following: acetic, propionic, butyric and isobutyric acids, 0.1-0,2; valeric and isovaleric acids, 

 0.05-0.1; caproic, isocaproic, heptylic and octylic acids, 0.01-0.03; nonylic acid, O.Ol; decylic acid, 0.005-0.008. 

 Some of the negative results tabulated may be incorrect if toxic concentrations were employed. In general, toxicity 

 Increases with the length of the chain of carbon atoms and with the decrease in the pH of the medium. /l5/ Acid em- 

 ployed at toxic concentrations, /it/ Colorless forms utilize the same nitrogen sources in light as in darkness. For 

 photosynthetic forms, data pertain to utilization in light; the same nitrogen sources which are utilized in darkness are 

 indicated by Fn 18. Some of the amino acids listed may, where utilized, also serve as a carbon source for some organ- 

 isms, /it/ Also utilized in darkness. /l8/ Negative results may not be valid because tests were conducted in a medium 

 lacking thiamine. /19/ Growth is obtained only if thiamine is present. /20/ When utilized, it is a good carbon source. 



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