1924] 
WOLPERT—FUNGI AND H-ION CONCENTRATION OF MEDIA 57 
in neither case does the fungus grow in & slightly alkaline solution. 
Although 35° C. is the optimum temperature for growth in the 
Richards' solution, in the peptone it shows no advantage over the 
other two. Тһе optima Pg ranges do not vary materially in 
either case except for the secondary maxima found in the peptone 
solution at 15° C. and 35? C. In both cases the active acidity 
of the medium is slightly increased. In the majority of instances 
the final Рн is close to the hydrogen-ion concentration which 
inhibits the mycelial growth of this fungus. 
In the Richards' solution at 15? C. the mycelium of Daedalea 
confragosa (table v, fig. 3) shows a very narrow range of growth, 
between Рн 4.0 and 5.5. At 25° C. and 35° C. the Ри limit on 
the acid side is 3.5, but on the alkaline side it is 7.0 at 35? C. 
and 7.2 for 25? С. Тһе optimum range for the two higher tem- 
peratures lies between Pg 5.5 and 7.0, with a slow decrease in 
growth as the solutions become more acid, and a sharp drop 
to 0 after passing the neutral point. 
TABLE V 
THE GROWTH OF DAEDALEA созго AND THE CHANGES IN THE 
ACTIVE ACIDITY UPON BOTH CHARDS' AND PEPTONE 
SOLUTIONS AT DIFFERENT SEP S AND TEMPERATURES 
15° C. 25° C. 35° C. 
Рн Wt. of Рн | Wt. of Ри Wt. of 
mat in mat in mat in 
Initial| Final mgs. Initial | Final mgs. Initia] | Final 
3.5 | 3.5 0 £xsi ss 0 
| 4.0 3.9 4.0 3.6 trace 4.0 8.7 86 
8-45 1 92.2 15 £35 115 28 45 1 39 Г 48 
“| 5.0 | 4.7 27 5.0 | 3.5 37 49 | 3.9 | 48 
5.5 | 5.5 0 5.4 | 3.8 41 6.4138 | 44 
5.9 | 4.4 51 E GEM WIS 
E 6.5 5.9 48 6.6 + 67 48 
= 71 | 6.3 47 6Е 1 6.5 | 57 
79 1 72 0 70 | 7.0 0 
28 | 2.8 0 28 | 2.8 0 
3.3 | 33 0 8.5 | 6.5 332 3.6 | 6.5 | 210 
al 4.0 | 4.7 166 4.0 | 6.4 267 4.0 | 6.6 | 188 
&| 45 | 57 197 43 | 6.7 213 42 | 5.7 | 128 
8| 4.9 | 6.0 198 5.0 | 6.6 212 $01 83 м 
S$} 55 | 55 150 £6 1 63 330 5.4 | 5.5 | 99 
& 6.0 | 5.8 138 6.0 | 6.3 333 5.9 | 6.2 | 110 
&| 66 | 62 142 6.4 | 6.6 197 6.5 | 5.6 | 82 
T0 1-59 100 TD | 6:9 71 пе 147313] 9t 
7.6 FT 0 7.5 | 7.5 0 7.5 | 7.5 0 
