Physiology of the Genus Eidamia . 413 
percentage concentrations were employed. Experiments were made on 
several occasions' using different batches of similarly prepared media, and 
the cultures were kept at various temperatures, approximately constant for 
each experiment. In a particular experiment (16*5° to 18*2° C.) using 
E. catenulata the total growth at the end of ten days was as follows : 
Growth in diameter (cm.) of E. catenulata on agar containing organic 
acid in different concentrations. 
Acid. 
1*0 
o -5 
0.25 
0-1 
0-05 % 
Control. 
Malic 
3*9 
4.1 
4-0 
4.4 
4.2 
) 
Citric 
4.1 
4 *o 
3-9 
3‘9 
4.2 
■"v— 
to 
CO 
Tartaric 
4.1 
4.0 
3*9 
4*2 
3-9 
J 
At these relatively low acid concentrations the rate of growth is very 
similar throughout a given series, and in each case there is more growth than in 
the control plates. Although the rate of growth in tartaric is nearly equal to 
that in malic and citric acids, the fungus forms growth of a more meagre 
character and produces fewer spore masses, hence it is not surprising that the 
amount of tartaric acid utilized by the fungus after a long period (see section 
relating to utilization of acid) is less than that of malic or citric acid. 
Somewhat similar results were obtained for E. viridescens, but in the case of 
E. acremonioides no growth.was obtained in the malic, citric, and tannic acid 
series, with the exception of 0-05 per cent, citric, where growth was of a very 
meagre character. 
Growth in diameter (cm.) of E. catenulata on agar containing 
tannic acid in different concentrations. 
Concentration. 
4 
5 
Interval in days. 
6 7 
9 
10 
2-0 
— 
— 
— 
— 
— 
2.5 x 1 
i -5 
o -35 
0.7 
1.05 
i -35 
2*0 
2-3 
1-0 
o-6 
°-95 
i-8 
2*S 
3-2 
o *5 
0.65 
1.1 
i-6 
2-0 
3 -o 
3‘45 
0.25 
0.7 
1-2 
W 
2-1 
3*15 
3-55 
0-1 
0.8 
‘ i *3 
i-7 
2.25 
3-3 
3-3 
C. 1 
0-55 
1 -05 
x *45 
I.9 
2, 55 
3-°5 
C. 2 
o-6 
1.1 
1.4 
i*8 
2.5 
2-95 
At the end of ten days, growth in all concentrations except 1-5 and 2 
is greater than that in the controls. 
Growth was considerably checked in the 2 per cent, series; slight 
growth of an irregular character was observed on the seventh day. 
The growth-rate increased very slightly, passing from the 1-5 to o-i con¬ 
centrations although the hydrogen-ion concentration exhibits little change 
(2 per cent. — pH 4-4 ; 1 per cent. = pH 4-4). 
