180 EXPERIMENT STATION RECORD. 



The physiological function of potash in plants, J. Stoklasa {Ztschr. Lnndw. 

 Versuch.sw. Ostcrr., Jl (JDOH), Xo. 1, pp. 52-61). — A preliiuinary account is 

 given of experiments whicli were conducted with sugar beets and barley, to 

 determine the physiological importance of potash for the growth and develop- 

 ment of those plants. A lack of potash was found to interfere seriously with 

 the photosynthesis of the plants. Where plants were grown under control con- 

 ditions those receiving potash had a much higher content of starch and sugar 

 than those where it was wanting or where the amount was deficient. In both 

 barley and beets the ash from the above-ground or green parts of the plants 

 was nuich richer in jiotash than was the ash of the roots. There ai)i»ears to 

 be an intimate connection between the assimilable potash present and the carbon 

 dioxid assimilation of jilants. 



The influence of lig'ht and of copper on fermentation, .1. E. Purvis and 

 W. A. K. WiLKs (Proc. Camhridge Phil. Soc, Uf (1907), No. .). pp. 361~S7.i; 

 Chem. News, 97 (1908), Nos. 2516, pp. 79-81; 2517, pp. 87-89).— TXw results are 

 given of a comparative study of the influence of light and various colors upon 

 fermentation when conducted in unsterilized copper vessels, in sterilized ghiss 

 vessels, and in unsterilized glass and copper vessels. The effects of the intiu- 

 ence were traced in determinations of the optical activity, copper <^)xid reducing 

 power, nitrogen content, acidity, and specific gravity of the distilled fermented 

 solutions. 



It was found that fermentation when carried on under sterilized and unsteril- 

 ized conditions in glass vessels and under the influence of various colors, as 

 well as of white light and also in darkness, was not seriously affected, as shown 

 by determinations of the optical activities of the fermented solutions. 



Fermentation when conducted in copper vessels, but otherwise under the 

 same conditions, was found to be influenced very markedly, as shown by differ- 

 ences in the acidity, optical activity, etc., of the solutions. The light of different 

 colors influenced the changes indirectly. It appears that copper dissolved from 

 fermenting vessels very largely determined the course of fermentation. The 

 I'esults obtained under the influence of blue light proved that the inhibitory 

 effect of this light on the development of acidifying bacteria decreased the 

 amount of acid produced and therefore lessened the amount of copper dissolved. 

 On the other hand, the fermentations under the influence of red light and in 

 darkness gave better facilities for a more vigoi-ous growth of the bacteria. The 

 acid produced under these conditions dissolved a little of the copper, and its 

 inhibitory eft'ect on a normal growth of the yeast and a regular fermentation 

 is evident from the results obtained in the different determinations. 



Various contributory causes were noted, among them the influence of temper- 

 ature, which varied under the different colored lights. It was further found 

 that the original composition of the wort exercises an effect upon the resulting 

 fermentation, a good yeast appearing to resist the action of copper better than 

 a poor one. 



On the variation of peroxidase in seeds, Brocq-Rousseu and E. Gain ( Compt. 

 Rend. Acad. Sci. [Paris], 1J,6 (1908), No. 10, pp. 54o-5//8).— In a previous note 

 (E. S. R., 19, p. 931) the authors report the discovery of the fact that perox- 

 idases do not persist indefinitely in seeds. In the present paper an account is 

 given of an attempt made to determine the length of time that peroxidase could 

 be recognized in seed, the specimens examined varying from 2 to 2,000 years 

 in age. 



The oldest seeds to show the presence of peroxidase were Tritimim hyhernnm 

 and T. monococciim, which were about 208 years old. The seeds of a few other 

 species of plants that were more than 100 years old showed the reaction for 



