532 Chaudhuri.—A Study of the Growth in 
end of the second week, and that in the following two weeks there was very- 
little growth. 
A second set of experiments was then started in which air was gently 
bubbled continuously through the liquid in the flasks, and a set of eight 
flasks from the aerated ones and another set of eight from the non-aerated 
ones were taken away every five days for dry-weight determination for 
a period of fifteen days. The result was very striking ; after the first 
five days the dry weight was nearly double that of the non-aerated ones. 
After ten days the difference was still very great ; after fifteen days, how- 
Days 5 10 15 
Fig. 9. Dry-weight production of V. albo-atmm in aerated and non-aerated 
cultures in Coon’s medium. 
ever, the ratio was falling. These results are represented graphically in 
Fig. 9. At the end of five days the aerated cultures weighed on an average 
°-°659 + °-°°27 grm., whereas the non-aerated onesgave only00381 + 0-0028 
grm. After ten days the aerated gave 0-1942 + o-oo6grm. and the non-aerated 
o* 1107 + 0-0056 grm. ; and after fifteen days 0*3239+ 0-0114 grm., and 
0-2099 + 0-0058 grm. respectively. These figures, which are in all cases the 
mean of eight samples, show that the differences are very significant. 
In this experiment all the media, viz. Coon’s, pea broth, tomato juice, 
prune juice, potato extract, Richard’s synthetic, &c., in which the fungus 
grew were rendered alkaline. The highest degree of alkalinity reached 
in Coon’s medium was pH 8-2 after six months, the normal pH of the 
