412 
Horne and Williamson .— The Morphology and 
each case. Since the specific rotation of tartaric is 15-06, the rotation for 
a 2 per cent, solution would be only 0-30 approximately— 
/ . rotation per decimetre length\ 
( specific rotation =-:- ); 
V cone, in grm. per 1 c.c. / 
therefore when small amounts of acid are utilized it would be difficult to 
obtain a polarimeter reading which would fall outside the limits of probable 
error. For this reason this method was abandoned. It was also found 
impractical to work with synthetic nutrient media, such as Coon’s, with 
racemic acid added, since the angle of rotation is often greatly affected by 
the presence of the optically active carbohydrate or protein which these 
media contain. Pasteur ( 13 ) found that when some pure ammonium 
racemate is dissolved in water containing a small quantity of phosphates 
and inoculated with Penicillium glaucum this fungus is able to grow 
and sporulate : correlated with this growth the dextrorotatory modi¬ 
fication of racemic acid disappears, leaving only levorotatory acid. 
Accordingly some ammonium racemate was prepared by taking 100 c.c. 
of 5 per cent, racemic acid and adding to it 18-4 c.c. of ammonia of strength 
o -22 N. This amount of ammonia should neutralize the racemic acid. To 
this solution 0-148 grm. K 3 P 0 4 were added. This medium was then auto¬ 
claved, and flasks, containing 25 c.c. of solution each, were inoculated with 
Eidamia catemdata , E. viridescens , and Penicillium glaucum. The usual 
controls were set up. At the end of three months P. glaucum had pro¬ 
duced numerous colonies, but no growth had taken place in the flasks 
containing E. catemdata and E. viridescens. This result was the opposite 
to that obtained when the fungi were grown in tartaric acid without other 
source of nutrient. Hence, from the evidence, neither E. catemdata nor 
E. viridescens appears to resemble Penicillium glaucum in its behaviour 
towards organic acids exhibiting stereo-isomerism. Where growth in 
these acids occurs it seems probably due to a reaction analogous to certain 
bacterial acid fermentations, such as the fermentation of malic acid by 
B. lactis aerogenes and citric acid by B. cloacae . 
D. Growth on Agar with Organic Acid in Various Concentrations. 
The general method adopted for these experiments was to prepare a 
number of flasks, containing a known quantity each of neutralized agar 
solution made up with distilled water, and an equal number of test-tubes, 
containing small measured quantities of acid of different known concentra¬ 
tions, devised with a view to obtaining, upon adding the acid to the agar, 
a series of media containing definite percentage concentrations of each acid. 
The flasks and tubes were autoclaved and the acids rapidly added to 
the flasks after autoclaving and before the agar had commenced to solidify. 
In the case of malic, citric, and tartaric acids, 1, 0-5, 0-25, o-i, and 0-05 
f 
