STEINBERG: ZINC SULPHATE AND ASPERGILLUS NIGER 291 
7Н.О (Kahlbaum). Room temperature (18-23? C.). Period of 
growth ten days. 
Jena Kavalier Bohemian | Pyrex 
No zinc 1o mg. Zn/L No zinc | 1o mg, Zn/L | No zinc 1o mg. Zn/L 
0.989 gr. 0.980 gr. 0.270 gr. | о. 9024 gr. | O.3I9 gr. 0.940 gr. 
а" 0.940 “ бада”! -943 | 0.248 “ 0.980 '' 
0.919 “ 1005. 0.285 “| 0.886 И Ви 0:017: " 
қоза” 0.988 '' 0.300: "7 0:047 С 3- 7094252 ^ 0.053 ~” 
0.053 '' 1.022 “ рі И onem" ЫЗ " 1 ep ^ 
0.950 '' 0.987 “ 6.301 “ | 0.943 “ | 0.287 " · | 0.957 de 
1 | 
With nutrient solutions to which no zinc has been added а 
distinct difference is displayed, as concerns the yield, between 
the Jena flasks, on the one hand, and the Kavalier and Pyrex 
on theother. The low yields characteristic of the zinc-free culture 
are obtained only in the latter two glasses. 
Cultures grown in the presence of 10 mg. zinc (calculated as 
metal) per liter attained a dry weight of approximately one gram 
irrespective of the kind of flask used. 
Additional experiments bringing out the increased growth 
taking place in a culture medium to which no zinc has been inten- 
tionally added when in Jena glass are as follows: 
4. THE INFLUENCE OF A ZINC GLASS (JENA) ON THE YIELD 
Pfeffer solution: water redistilled through glass; “Crystal 
Domino" sucrose; NH4,NO; (Merck); KH;PO, (Baker); MgSOx.- 
7Н.О (Kahlbaum). Temperature 30-31? C. Period of growth 
seven days. No zinc added. 
Pyrex Jena 
0.247 p RIEN. ЖОК NET ди Chere sr E ҮН 0.948 еи 
Ие о иеа VEI NN Mfr 0.896 
боза du EL 2а қоза төсе rte pe napi 3 
Ла ara ep ueris 0.904 “ 
GER УЖ оа тие heat e REESE 0.904 “ 
МӘННЕН ы а en c +? 0.909 “ 
6.336 ата ое аа нена мотае 0.915 grams 
ee ieee bee ет eee ++: 0.849 
934965 Се pee ones sud 0,881 7“ 
9.332 “ o.872 “ 
О qo ыр. ыы анык T E ES o.864 “ 
(е 0.876-“ 
