(Vor. 11 
80 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
TABLE XII 
GROWTH AND CHANGES IN THE ACTIVE ACIDITY AT 25? C. AND AT DIF- 
FERENT INITIAL Рн IN A SOLUTION WITH PEPTONE AS THE 
ONLY SOURCE OF CARBON AND NITROGEN 
Fungi 
Schizophyllum Polyporus Lenzites Pleurotus 
commune ` adustus sepiaria ostreatus 
Wt. of Wt. of Wt. of Wt. of 
Рв mat іп Рн mat in Рн mat in Рн mat in 
mgs. mgs. mgs. mgs. 
8.0 | 3.0 47 8.0 |8.0 37 13.0 |8.0 24 8.0 |3.0 0 
4.1 | 5.6 84 4.1 | 6.6 99 |4.1 | 6.6 91 4.0 |7:8| 139 
5.0| 5.9 70 5.0 | 6.0 67 15.0 | 6.7 2 5.0 |7.2| 185 
6.0 | 6.0 62 6.0 | 6.6 75 6.0 | 7.3 8 6.0 | 7.9 89 
7.0 | 6.7 70 7.0 | 6.9 40-17.01 7.2 9 7.01|8.0 78 
Pholiota illaria Polystictus Daedalea 
adiposa nellea versicolor confra 
8.0 | 3.5 81 8.0 | 3.2 25 |3.0|3.1 31 3.0 | 3.0 0 
4.0 | 5.6 53 4.0} 6.6] 102 | 4.0 A 51 4.0|6.6| 127 
5.0 | 6.8 76 5.0 | 6.7 96 |5.0|5.5 89 5.0 | 6.8| 118 
6.0 | 7.0 53 6.0 | 7.4 95 | 6.0 | 5.4 33 6.0 | 6.9 89 
7.0 | 7.4 49 7.01 7.4 36 | 7.0 | 7.5 41 7.0 | 7.2 41 
In every case the active acidity of the solutions with the initial | | 
Рн 3.0 is not materially altered by growth, while іп the majority 
of cases in those solutions with an initial acidity of Рн 4.0, 5.0, 
and 6.0, the active acidity is reduced close to neutrality. Ехсер- | 
tions to this are: Polystictus versicolor at Py 6.0, Polyporus adustus 
at Py 7.0, and Schizophyllum commune at Рн 6.0 and 7.0. In 
these cases the active acidity is slightly increased. The acidity | 
is decreased less by Polystictus versicolor and more by Pleurotus 
ostreatus than by the other species, the final values ranging from | 
5.4 to 5.5 in the first case and from 7.2 to 8.0 in the second. 
The use of filter-paper strips and cellulose suspensions ib | 
cultures made it necessary to form some standard for measuring 
the amounts of growth other than by the dry weights of the mats. 
This was accomplished by comparing the growth in the cultures — 
with a definite scale ranging from 0 to 5, where 0 designates 10 | 
growth; 1, traces of submerged growth; 2,submerged growth more > 
than in 1 but less than 50 per cent of the surface covered; 3, 88 — 
in 2 but the surface more than 50 per cent and less than 100 рег | 
cent covered; 4, as in 2 but the surface entirely covered by а thin 2. 
film of mycelium; and 5, surface covered by а thicker mat than in- 
