1924] 
WOLPERT—FUNGI AND H-ION CONCENTRATION OF MEDIA 55 
dent that the actual acid limit for appreciable growth lies closer 
to Pa 4.0 than to 3.5. The best growth is obtained at Pa 6.0 
with à mat weighing 54 mgs. At 25? C., although growth is 
better than at 15? C., it has about the same range of Py while 
the optimum lies at 6.5 with 72 mgs. of felt. At 35° C. the fungus 
grows better than at either of the other temperatures and pro- 
duces а mat weighing 94 mgs. at Рн 6.7. At this temperature, 
however, there is no indication of increased tolerance to either 
alkalinity or acidity. In fact, Py 6.8 does not support growth as it 
does at 15° C. and 25° C., while the acid limit remains the same as 
at the lower temperatures. 
TABLE IV 
THE GROWTH OF LENZITES SEPIARIA AND THE CHANGES IN THE ACTIVE 
ACIDITY IN BOTH THE RICHARDS’ AND THE PEPTONE SOLU- 
TIONS AT DIFFERENT INITIAL Pu AND TEMPERATURES 
15? C. 25? C. 35? C. 
Рн Wt. of Рн Wt. of Рн Wt. of 
mat in mat in mat in 
Initial| Final mgs Initial| Final mgs Initial | Final mgs 
25125 2-134 0 55 1°35 0 
„кыр рат {тасе 221 97 44 4&2 | 3.5 67 
2| 4.5 | 3.7 39. 4.5 | 36 43 4451 38 54 
~| 5.0 | 3.6 42 5.0 | 3.6 38 $9137 61 
*| 55 | 44 47 55 | 3.6 37 54 | 3.9 88 
S| 6.0 | 5.0 54 co 47 48 E91] 39 89 
S| 6.5 | 5.8 39 6.5 | 5.0 72 k | 38 76 
®| 6.9 6.4 41 6.8 4.9 68 6.7 7.4 94 
та 127% 0 TI | Ll 0 6.9 | 6.9 0 
28 | 2.8 0 2.8 | 2.8 0 2.8 | 2.8 0 
85 124 71 3.5] 31 95 3.551 332 98 
2-401 8.8 146 23.8 | 84 139 46 123 98 
$1 44 | 3.3 137 4.6 | 3.4 99 4.6 | 3.8 78 
e| 5.0 | 3.3 141 831834 99 £3 1.5.8 85 
SEBET 3.2 141 5.7 | 3.5 101 es 1 9.3 | 10 
& 6.0 | 34 130 6.0 | 3.0 153 80138 | HT 
&| 6.5 | 3.8 120 6:41 S. 133 841 5858 |] 141 
7.0 | 4.5 115 7.0 | 4.0 76 6.8 | 3.8 99 
TA | 73 0 7.6 | 7.6 0 T6 75 0 
In the peptone solution (fig. 2) this fungus grows much better 
than in the Richards’ solution. Growth at 15^ C. is as good, if not 
slightly better, than that at either 25° С. or 35° С. The inhibiting 
reactions are P4 2.8 and 7.4. Maximum growth is obtained be- 
tween P4 4.0 and 5.7. Although growth is less pronounced at 
25° C. than at 15? C., the acid limit is not materially altered. А 
