280 Studies in Fat Metabolism of Timothy Grass Bacillus. 



A comparison of the composition of the growth on these media showed that 

 the acetic acid utilised in the presence of lactic acid or glucose served, not to 

 increase the general growth of the organism, but to increase the proportion 

 of lipoid material formed. This was shown to be a specific effect of the acetic 

 acid, and was not merely due to greater concentration of carbonaceous food 

 material. 



Experiments were made to ascertain whether the behaviour of the bacillus 

 on other straight-chain fatty acids resembled that on lactic acid (and glucose) 

 or that on acetic acid. Growth on propionic acid and on butyric acid was 

 like that on lactic acid, i.e., the organism was able to grow on these com- 

 pounds without the addition of other carbon compounds, and to synthesise 

 both nitrogenous and fatty material. 



The authors' thanks are due to Dr. Graham Smith for kindly providing a 

 strain of the Timothy grass bacillus. They gladly take this opportunity of 

 expressing their gratitude for the stimulating and encouraging criticism 

 afforded by Prof. F. G. Hopkins during the progress of this research. 



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(2) Hopkins and Fletcher, " Lactic Acid in Amphibian Muscle," ' J. of Physiology,' 



vol. 35, p. 247 (1907). 



(3) Van Slyke, " The Analysis of Proteins, etc.," 1 J. Biol. Chem.,' vol. 10, p. 15 (1911). 



(4) Wood and Berry, "A Bapid Method of Estimating Sugar," ' Proc. of the Cambridge 



Philosophical Society,' vol. 12, p. 97 (1903). 



