Physiology of the Genus Eidamia. 41 1 
are concerned, and hence the respective limits obtained for the species, viz. 
E. catenulata and E. viridescens , pH 8-2, and E. acremoniodes , pH 8, 
should be regarded as very approximate. 
C. Utilization of A cid. 
Since it was found that both E. catenulata and E. viridescens were 
capable of growth in solutions of acids made up in distilled water, in the 
absence of other source of nutrient, several experiments were made by titra¬ 
tion with standard alkali, with a view to ascertaining whether the acid was 
actually utilized. For the purpose of the experiments flasks containing 
50 c.c. of 1 per cent, solution of acid in distilled water were prepared. 
The flasks were set up in duplicate series and inoculated with E. catenulata 
and E. viridescens respectively. Control flasks were prepared, and flasks 
inoculated with Penicillium glaucum set up for comparison. In a particular 
experiment tartaric (pH 1-9), malic (pH 2-2), and citric (pH 2*i) acids were 
used. The cultures were kept at 25 0 C. for three months. At the end of 
this period the original volume of the liquid in the flasks had been some¬ 
what reduced owing to evaporation ; accordingly in the case of each acid 
the volume in the inoculated flasks was made up to those of its respective 
control, using conductivity water (neutral). The results are given below in 
terms of c.c. N/5 NaOH required to neutralize 10 c.c. of acid solution. 
Amount of growth and acid utilized in 1 per cent, solutions 
of certain organic acids. 
Acid. 
c.c. N/ 5 NaOH 
Growth. 
Tartaric control 
8-15 
— 
E. catenulata 
7‘7 
poor 
E. viridescens 
7*5 
poor 
P. glaucum 
8-i 
nil 
Malic control 
8-975 
— 
E. catemilata 
7-95 
moderate 
E. viridescens 
8-05 
moderate 
P. glaucum 
8.0 
moderate 
Citric control 
8.65 
— 
E. catenulata 
7-95 
poor 
E. viridescens 
8.3 
poor 
P. glaucum 
8-6 
nil 
The amount of growth corresponded fairly closely to the quantity of 
acid used in each case. 
P. glaucum differed from the species of Eidamia in producing no growth 
in 1 per cent, tartaric and citric acids. \t was at first thought that the 
action upon acid might be due to an avidity for one or other of the stereo- 
isomeric modifications of the organic acids employed. Accordingly, flasks, 
containing 2 per cent, racemic acid obtained from Kahlbaum made up with 
distilled water, were inoculated with Eidamia catenulata and E. viridescens 
respectively. The flasks were kept at 20° C. for one month. The solutions 
were then tested in the polarimeter, but there was no deviation from zero in 
