340 BOTANICAL GAZETTE [October 



determined and its rotation measured. In the experiments with fungi killed 

 by acetone, methyl alcohol, or other means, the powdered fungus material 

 was added to flasks containing solutions of the acids. The carbon dioxide 

 products and residual acid were determined as before. 



In the first experiments reported by Herzog and Meier 3 it was found that 

 the addition of lactic, tartaric, malic, mandelic, and /?-oxybutyric acids to 

 cultures of Penicillium glaucum, in which the carbon dioxide production had 

 become fairly constant, resulted in a great increase of the carbon dioxide 

 output. In every case the excess of carbon dioxide over the normal was much 

 greater than that calculated on the assumption that all of the acid used up 

 had been completely oxidized to carbon dioxide and water. Under the same 

 conditions glycollic, citric, pyrotartaric, and oxybutyric acids gave no increase 

 in the carbon dioxide production. The authors suggest that these experi- 

 ments indicate that the biological splitting of substances containing an asym- 

 metric carbon atom depends on a process of oxidation. Only the acids having 

 an asymmetric carbon atom were oxidized. 



To test this hypothesis further, experiments were carried out with fungous 

 material killed with acetone and methyl alcohol and finely pulverized. Defi- 

 nite quantities of the material were added to flasks containing solutions of 

 lactic acid or sodium lactate, and also to control flasks containing distilled 

 water. It was found that the carbon dioxide production in the flasks con- 

 taining the acid or its salt was slightly greater than in the controls. 



In a second paper* the method of experimentation with killed mycelia 

 is applied to the study of a number of other acids. The mycelia in these 

 experiments were immersed in liquid air, by which, it was assumed, the cells 

 were killed, although the spores were subsequently found to be alive. In these 

 experiments it was found that d-tartaric acid, /-tartaric acid, and (/-/-tartaric 

 acid were oxidized, while mesotartaric acid, which is not separable into optically 

 active components, was left intact. The dextro-rotatory form was oxidized 

 most rapidly. The optically active isomers of lactic acid showed scarcely 

 any difference in the rate of oxidation, while /-mandelic acid was oxidized 

 more rapidly than its antipode. Glycollic acid, having no asymmetric carbon 

 atom, was not attacked. The authors conclude that the preferential oxidation 

 of one component of a racemic mixture, which has heretofore been regarded 

 as biological selections of food substances, is merely the result of differences 

 in the reaction velocities of the antipodes with the substances of the 

 organisms. 



In continuation of the foregoing work, Herzog and Ripke* have studied 



* Herzog, R. O., und Meier, A., Ueber Oxydation durch Schimmelpilze. Zeitschr. 

 Physiol. Chem. 57: 35-42. 1908; also Meier, A., Dissertation under the same title. 

 Karlsruhe. 1909. 



ZWtf. 59:57-62. 1909. 



5 Herzog, R. O., und Ripke, O., Ueber das Verhalten einger Pilze zu organischen 

 Sauren. Ibid. 73-284-289. 1911. 



