924] 
WOLPERT—FUNGI AND H-ION CONCENTRATION OF MEDIA 67 
In the peptone solution (fig. 10) the Py limits at 15? C. are 3.0 
and 7.5, while at 25? C. and 35? C. they are 2.8 and 7.5. Here 
the differences in Ру are slight and point to no marked optimum 
temperature. On the other hand, growth is much more pro- 
nounced at 25? C. and 35? C. than at 15? C., and of these 2, 25? 
C. is the best. In this solution there is no outstanding Pg 
indicating an optimum hydrogen-ion concentration, for at 15° 
C. growth varies very little between Pg 3.5 and 6.5 and at 25° C. 
and 35° C. between 4.0 and 6.5. In solutions either more acid 
or more alkaline than the above values, Pholiota adiposa shows, 
by a sharp drop in growth, that it is not on a favorable medium 
with respect to hydrogen-ion concentration. 
TABLE VIII 
THE GROWTH OF E M mds е AND THE CHANGES d уб ие тобы 
ACIDITY UPO OTH E RICHARDS' AND РЕРТОМ 
TIONS AT Pico Bi S rea Рн AND СӘГ 
15° С. 25° С. 35° С. 
Рн Wt. of Ри Wt. of Рн Wt. of 
mat in mat in 7 mat in 
Initial | Final mgs. | Initial | Final mgs. | Initial | Final | mgs. 
2.8 | 2.8 0 
: $1133 15 3:0 1 3.0 0 
4 54 | 34 0 35 | $3 17 $5.1 %2 31 
S 3.6 24 3.8 3.6 25 3.8 3.4 39 
5| 41 | 4.0 30 Gic es 32 411 97 18 
8| 5.0 | 5.0 21 55.41 45 5.0 | 5.0 23 
8| 5.5 | 5.5 34 5.5 | 4.8 63 5.5 | 53 35 
&| 6.0 | 6.0 49 6.0 | 5.4 78 6.0 | 5.6 51 
6.5 | 6.4 28 6.4 | 6.0 36 6.5 | 6.0 44 
6.9 | 6.9 0 70179 0 6.9 | 6.9 0 
$51 860 0 28 1:34 0 2.8 | 2.8 0 
£5 1-24 154 2-6 | 43 169 3.5 | 48 | 122 
21 49 | 4.9 93 4.0 | 4.0 268 4.0 | 6.0 | 214 
&| 4.4 | 5.3 135 ås | 41 258 43 | 6.0 | 221 
2| 5.0 | 6.4 146 49 |] 41 253 29.1] 84 | 228 
S| 5.5 | 6.9 155 5A | 44 275 E3104 | 222 
ы 6.1 | 7.0 133 6.0 | 4.6 275 6.0 | 6.3 | 247 
Bl 6.5 7.8 142 6.5 4.6 241 6.5 4.6 244 
TU | 713 74 7.0 | 6.6 44 7.0 | 6.0 | 106 
LEES S 0 76 | 7.5 0 ТБ | 7.5 0 
In the Richards’ solution the growth of this fungus tends to 
increase slightly the active acidity (table уш). However, in no 
сазе does this increase amount to more than 1 whole Pg unit 
while in the majority of cases it is less than one-half of a unit. 
