318 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



[Vol. 10 



Raistriek and Clark ('19) determined the relation of various 

 carbon sources (organic acids) to oxalic acid formation by 

 Aspergillus niger. Oxalic acid was determined by precipitation 

 as calcium oxalate and titration with permanganate. The 

 results are summarized: 



1. Four carbon, dibasic acids gave good growth and a good 

 yield of (COOH) 2 . 



2. Four carbon, monobasic acids gave almost no growth and 

 (COOH),. 



3. Three carbon acids gave very good growth, but little or no 

 (COOH) ,. 



4. Two carbon acids, as acetic, gave good growth and yield of 

 (COOH) 2 , while glycollic and gly oxalic gave but fair growth and 

 no (COOH),. 



5. The one carbon acid, HCOOH, gave but fair growth and no 

 oxalic acid. 



A theory was given to account for the formation of (COOH) ,, 

 citric, and fumaric acids from sugars from other organic acids. 

 In the case of (COOH) , production from sugar, diketo adipic 

 acid is formed which is hydrolyzed to acetic and oxalic acids, 

 the CH.COOH then being also oxidized to (COOH) ,. With the 

 organic acids as C sources, oxalacetic acid is formed by hydrolysis 

 or oxidation or both, depending upon the organic acid used, and 

 this breaks to form (COOH) , and CH s COOH. The production 

 of citric and fumaric acids from sugar was supposed to proceed 

 through oxalacetic acid. The sources of the inorganic N (NH« 

 or NO, ions) were found to have no influence on the quantity 

 of (COOH), formed. 



Lampitt ('19) presented data relative to the N metabolism of 

 bread yeast. He determined total N by Kjeldahlization, NH 3 

 by distillation with MgO in vacuo, and sugar by Bertrand's 

 method. Deamidization of amino acids was not studied by de- 

 terminations of amino nitrogen but by the ammonia produced. 

 It was found that the removal of N from the nutrient was pro- 

 portional to the yeast present; and, as determined by counts and 

 N determinations, the greater the rapidity of budding during 

 active fermentation the greater the amount of N assimilated by 

 each cell. However, active reproduction was found in some 



